[v3,2/4] drm: Add support for ARM's HDLCD controller.

The HDLCD controller is a display controller that supports resolutions
up to 4096x4096 pixels. It is present on various development boards
produced by ARM Ltd and emulated by the latest Fast Models from the
company.

Cc: David Airlie <airlied@linux.ie>
Cc: Robin Murphy <robin.murphy@arm.com>

Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>
---
 drivers/gpu/drm/Kconfig          |   2 +
 drivers/gpu/drm/Makefile         |   1 +
 drivers/gpu/drm/arm/Kconfig      |  29 ++
 drivers/gpu/drm/arm/Makefile     |   2 +
 drivers/gpu/drm/arm/hdlcd_crtc.c | 334 +++++++++++++++++++++++
 drivers/gpu/drm/arm/hdlcd_drv.c  | 555 +++++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/arm/hdlcd_drv.h  |  42 +++
 drivers/gpu/drm/arm/hdlcd_regs.h |  87 ++++++
 8 files changed, 1052 insertions(+)
 create mode 100644 drivers/gpu/drm/arm/Kconfig
 create mode 100644 drivers/gpu/drm/arm/Makefile
 create mode 100644 drivers/gpu/drm/arm/hdlcd_crtc.c
 create mode 100644 drivers/gpu/drm/arm/hdlcd_drv.c
 create mode 100644 drivers/gpu/drm/arm/hdlcd_drv.h
 create mode 100644 drivers/gpu/drm/arm/hdlcd_regs.h

On Wed, Dec 02, 2015 at 04:33:31PM +0100, Daniel Vetter wrote:
> On Wed, Dec 02, 2015 at 04:24:19PM +0100, Daniel Vetter wrote:
> > On Wed, Dec 02, 2015 at 12:23:00PM +0000, Liviu Dudau wrote:
> > > The HDLCD controller is a display controller that supports resolutions
> > > up to 4096x4096 pixels. It is present on various development boards
> > > produced by ARM Ltd and emulated by the latest Fast Models from the
> > > company.
> > > 
> > > Cc: David Airlie <airlied@linux.ie>
> > > Cc: Robin Murphy <robin.murphy@arm.com>
> > > 
> > > Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>
> > 
> > A few small nitpicks below.
> 
> I've forgotten to add Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> with these all addressed.

Thanks! I'll make the changes and post them lately.

Best regards,
Liviu

> -Daniel
> 
> > 
> > > ---
> > >  drivers/gpu/drm/Kconfig          |   2 +
> > >  drivers/gpu/drm/Makefile         |   1 +
> > >  drivers/gpu/drm/arm/Kconfig      |  29 ++
> > >  drivers/gpu/drm/arm/Makefile     |   2 +
> > >  drivers/gpu/drm/arm/hdlcd_crtc.c | 334 +++++++++++++++++++++++
> > >  drivers/gpu/drm/arm/hdlcd_drv.c  | 555 +++++++++++++++++++++++++++++++++++++++
> > >  drivers/gpu/drm/arm/hdlcd_drv.h  |  42 +++
> > >  drivers/gpu/drm/arm/hdlcd_regs.h |  87 ++++++
> > >  8 files changed, 1052 insertions(+)
> > >  create mode 100644 drivers/gpu/drm/arm/Kconfig
> > >  create mode 100644 drivers/gpu/drm/arm/Makefile
> > >  create mode 100644 drivers/gpu/drm/arm/hdlcd_crtc.c
> > >  create mode 100644 drivers/gpu/drm/arm/hdlcd_drv.c
> > >  create mode 100644 drivers/gpu/drm/arm/hdlcd_drv.h
> > >  create mode 100644 drivers/gpu/drm/arm/hdlcd_regs.h
> > > 
> > > diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
> > > index c4bf9a1..3fd9124 100644
> > > --- a/drivers/gpu/drm/Kconfig
> > > +++ b/drivers/gpu/drm/Kconfig
> > > @@ -106,6 +106,8 @@ config DRM_TDFX
> > >  	  Choose this option if you have a 3dfx Banshee or Voodoo3 (or later),
> > >  	  graphics card.  If M is selected, the module will be called tdfx.
> > >  
> > > +source "drivers/gpu/drm/arm/Kconfig"
> > > +
> > >  config DRM_R128
> > >  	tristate "ATI Rage 128"
> > >  	depends on DRM && PCI
> > > diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
> > > index 1e9ff4c..6b42d75 100644
> > > --- a/drivers/gpu/drm/Makefile
> > > +++ b/drivers/gpu/drm/Makefile
> > > @@ -35,6 +35,7 @@ CFLAGS_drm_trace_points.o := -I$(src)
> > >  
> > >  obj-$(CONFIG_DRM)	+= drm.o
> > >  obj-$(CONFIG_DRM_MIPI_DSI) += drm_mipi_dsi.o
> > > +obj-$(CONFIG_DRM_ARM)	+= arm/
> > >  obj-$(CONFIG_DRM_TTM)	+= ttm/
> > >  obj-$(CONFIG_DRM_TDFX)	+= tdfx/
> > >  obj-$(CONFIG_DRM_R128)	+= r128/
> > > diff --git a/drivers/gpu/drm/arm/Kconfig b/drivers/gpu/drm/arm/Kconfig
> > > new file mode 100644
> > > index 0000000..5e8c8a8
> > > --- /dev/null
> > > +++ b/drivers/gpu/drm/arm/Kconfig
> > > @@ -0,0 +1,29 @@
> > > +config DRM_ARM
> > > +	bool "ARM Ltd. drivers"
> > > +	depends on DRM && OF && (ARM || ARM64)
> > > +	select DRM_KMS_HELPER
> > > +	help
> > > +	  Choose this option to select drivers for ARM's devices
> > > +
> > > +config DRM_HDLCD
> > > +	tristate "ARM HDLCD"
> > > +	depends on DRM_ARM
> > > +	depends on COMMON_CLK
> > > +	select COMMON_CLK_SCPI
> > > +	select DMA_CMA
> > > +	select DRM_KMS_CMA_HELPER
> > > +	select DRM_GEM_CMA_HELPER
> > > +	help
> > > +	  Choose this option if you have an ARM High Definition Colour LCD
> > > +	  controller.
> > > +
> > > +	  If M is selected the module will be called hdlcd.
> > > +
> > > +config DRM_HDLCD_SHOW_UNDERRUN
> > > +	bool "Show underrun conditions"
> > > +	depends on DRM_HDLCD
> > > +	default n
> > > +	help
> > > +	  Enable this option to show in red colour the pixels that the
> > > +	  HDLCD device did not fetch from framebuffer due to underrun
> > > +	  conditions.
> > > diff --git a/drivers/gpu/drm/arm/Makefile b/drivers/gpu/drm/arm/Makefile
> > > new file mode 100644
> > > index 0000000..89dcb7b
> > > --- /dev/null
> > > +++ b/drivers/gpu/drm/arm/Makefile
> > > @@ -0,0 +1,2 @@
> > > +hdlcd-y := hdlcd_drv.o hdlcd_crtc.o
> > > +obj-$(CONFIG_DRM_HDLCD)	+= hdlcd.o
> > > diff --git a/drivers/gpu/drm/arm/hdlcd_crtc.c b/drivers/gpu/drm/arm/hdlcd_crtc.c
> > > new file mode 100644
> > > index 0000000..350c1fe
> > > --- /dev/null
> > > +++ b/drivers/gpu/drm/arm/hdlcd_crtc.c
> > > @@ -0,0 +1,334 @@
> > > +/*
> > > + * Copyright (C) 2013-2015 ARM Limited
> > > + * Author: Liviu Dudau <Liviu.Dudau@arm.com>
> > > + *
> > > + * This file is subject to the terms and conditions of the GNU General Public
> > > + * License.  See the file COPYING in the main directory of this archive
> > > + * for more details.
> > > + *
> > > + *  Implementation of a CRTC class for the HDLCD driver.
> > > + */
> > > +
> > > +#include <drm/drmP.h>
> > > +#include <drm/drm_atomic_helper.h>
> > > +#include <drm/drm_crtc.h>
> > > +#include <drm/drm_crtc_helper.h>
> > > +#include <drm/drm_fb_helper.h>
> > > +#include <drm/drm_fb_cma_helper.h>
> > > +#include <drm/drm_gem_cma_helper.h>
> > > +#include <drm/drm_of.h>
> > > +#include <drm/drm_plane_helper.h>
> > > +#include <linux/clk.h>
> > > +#include <linux/of_graph.h>
> > > +#include <linux/platform_data/simplefb.h>
> > > +#include <video/videomode.h>
> > > +
> > > +#include "hdlcd_drv.h"
> > > +#include "hdlcd_regs.h"
> > > +
> > > +/*
> > > + * The HDLCD controller is a dumb RGB streamer that gets connected to
> > > + * a single HDMI transmitter or in the case of the ARM Models it gets
> > > + * emulated by the software that does the actual rendering.
> > > + *
> > > + */
> > > +
> > > +static const struct drm_crtc_funcs hdlcd_crtc_funcs = {
> > > +	.destroy = drm_crtc_cleanup,
> > > +	.set_config = drm_atomic_helper_set_config,
> > > +	.page_flip = drm_atomic_helper_page_flip,
> > > +	.reset = drm_atomic_helper_crtc_reset,
> > > +	.atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
> > > +	.atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
> > > +};
> > > +
> > > +static struct simplefb_format supported_formats[] = SIMPLEFB_FORMATS;
> > > +
> > > +/*
> > > + * Setup the HDLCD registers for decoding the pixels out of the framebuffer
> > > + */
> > > +static int hdlcd_set_pxl_fmt(struct drm_crtc *crtc)
> > > +{
> > > +	unsigned int btpp, default_color = 0x00000000;
> > > +	struct hdlcd_drm_private *hdlcd = crtc_to_hdlcd_priv(crtc);
> > > +	uint32_t pixel_format;
> > > +	struct simplefb_format *format = NULL;
> > > +	int i;
> > > +
> > > +#ifdef CONFIG_DRM_HDLCD_SHOW_UNDERRUN
> > > +	default_color = 0x00ff0000;	/* show underruns in red */
> > > +#endif
> > > +
> > > +	if (!crtc->primary->state->fb) {
> > > +		DRM_ERROR("No fb associated with state %p\n",
> > > +			  crtc->primary->state);
> > > +		return -EINVAL;
> > 
> > The higher-level ->mode_set_nofb can't fail and you're violating this
> > here. Correct fix in atomic is to check in your crtc->atomic_check that
> > there's always a primary fb set. Since that's a small dance (you need to
> > grab the primary plane state first) might be good to extract it into a
> > small helper, but not really needed.
> > 
> > Here you should WARN_ON if this ever happens and just return (without
> > trying to track an error code), since it's too late already.
> > 
> > > +	}
> > > +
> > > +	pixel_format = crtc->primary->state->fb->pixel_format;
> > > +
> > > +	for (i = 0; i < ARRAY_SIZE(supported_formats); i++) {
> > > +		if (supported_formats[i].fourcc == pixel_format)
> > > +			format = &supported_formats[i];
> > > +	}
> > > +
> > > +	if (!format) {
> > > +		DRM_ERROR("Format not supported: 0x%x\n", pixel_format);
> > > +		return -EINVAL;
> > > +	}
> > 
> > Same here. Although this should be impossible, with atomic the
> > core/helpers pre-check the pixel format against the format table you
> > register on the (primary) plane already. So just WARN_ON + bailing out.
> > 
> > > +
> > > +	/* HDLCD uses 'bytes per pixel', zero means 1 byte */
> > > +	btpp = (format->bits_per_pixel + 7) / 8;
> > > +	hdlcd_write(hdlcd, HDLCD_REG_PIXEL_FORMAT, (btpp - 1) << 3);
> > > +
> > > +	/*
> > > +	 * The format of the HDLCD_REG_<color>_SELECT register is:
> > > +	 *   - bits[23:16] - default value for that color component
> > > +	 *   - bits[11:8]  - number of bits to extract for each color component
> > > +	 *   - bits[4:0]   - index of the lowest bit to extract
> > > +	 *
> > > +	 * The default color value is used when bits[11:8] are zero, when the
> > > +	 * pixel is outside the visible frame area or when there is a
> > > +	 * buffer underrun.
> > > +	 */
> > > +	hdlcd_write(hdlcd, HDLCD_REG_RED_SELECT, default_color |
> > > +		format->red.offset | (format->red.length & 0xf) << 8);
> > > +	hdlcd_write(hdlcd, HDLCD_REG_GREEN_SELECT, default_color |
> > > +		format->green.offset | (format->green.length & 0xf) << 8);
> > > +	hdlcd_write(hdlcd, HDLCD_REG_BLUE_SELECT, default_color |
> > > +		format->blue.offset | (format->blue.length & 0xf) << 8);
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static void hdlcd_crtc_mode_set_nofb(struct drm_crtc *crtc)
> > > +{
> > > +	struct hdlcd_drm_private *hdlcd = crtc_to_hdlcd_priv(crtc);
> > > +	struct drm_display_mode *m = &crtc->state->adjusted_mode;
> > > +	struct videomode vm;
> > > +	unsigned int polarities, line_length, err;
> > > +
> > > +	vm.vfront_porch = m->crtc_vsync_start - m->crtc_vdisplay;
> > > +	vm.vback_porch = m->crtc_vtotal - m->crtc_vsync_end;
> > > +	vm.vsync_len = m->crtc_vsync_end - m->crtc_vsync_start;
> > > +	vm.hfront_porch = m->crtc_hsync_start - m->crtc_hdisplay;
> > > +	vm.hback_porch = m->crtc_htotal - m->crtc_hsync_end;
> > > +	vm.hsync_len = m->crtc_hsync_end - m->crtc_hsync_start;
> > > +
> > > +	polarities = HDLCD_POLARITY_DATAEN | HDLCD_POLARITY_DATA;
> > > +
> > > +	if (m->flags & DRM_MODE_FLAG_PHSYNC)
> > > +		polarities |= HDLCD_POLARITY_HSYNC;
> > > +	if (m->flags & DRM_MODE_FLAG_PVSYNC)
> > > +		polarities |= HDLCD_POLARITY_VSYNC;
> > > +
> > > +	line_length = crtc->primary->state->fb->pitches[0];
> > > +
> > > +	/* Allow max number of outstanding requests and largest burst size */
> > > +	hdlcd_write(hdlcd, HDLCD_REG_BUS_OPTIONS,
> > > +		    HDLCD_BUS_MAX_OUTSTAND | HDLCD_BUS_BURST_16);
> > > +
> > > +	hdlcd_write(hdlcd, HDLCD_REG_FB_LINE_LENGTH, line_length);
> > > +	hdlcd_write(hdlcd, HDLCD_REG_FB_LINE_PITCH, line_length);
> > > +	hdlcd_write(hdlcd, HDLCD_REG_FB_LINE_COUNT, m->crtc_vdisplay - 1);
> > > +	hdlcd_write(hdlcd, HDLCD_REG_V_DATA, m->crtc_vdisplay - 1);
> > > +	hdlcd_write(hdlcd, HDLCD_REG_V_BACK_PORCH, vm.vback_porch - 1);
> > > +	hdlcd_write(hdlcd, HDLCD_REG_V_FRONT_PORCH, vm.vfront_porch - 1);
> > > +	hdlcd_write(hdlcd, HDLCD_REG_V_SYNC, vm.vsync_len - 1);
> > > +	hdlcd_write(hdlcd, HDLCD_REG_H_BACK_PORCH, vm.hback_porch - 1);
> > > +	hdlcd_write(hdlcd, HDLCD_REG_H_FRONT_PORCH, vm.hfront_porch - 1);
> > > +	hdlcd_write(hdlcd, HDLCD_REG_H_SYNC, vm.hsync_len - 1);
> > > +	hdlcd_write(hdlcd, HDLCD_REG_H_DATA, m->crtc_hdisplay - 1);
> > > +	hdlcd_write(hdlcd, HDLCD_REG_POLARITIES, polarities);
> > > +
> > > +	err = hdlcd_set_pxl_fmt(crtc);
> > > +	if (err)
> > > +		return;
> > > +
> > > +	clk_set_rate(hdlcd->clk, m->crtc_clock * 1000);
> > > +}
> > > +
> > > +static void hdlcd_crtc_enable(struct drm_crtc *crtc)
> > > +{
> > > +	struct hdlcd_drm_private *hdlcd = crtc_to_hdlcd_priv(crtc);
> > > +
> > > +	clk_prepare_enable(hdlcd->clk);
> > > +	hdlcd_write(hdlcd, HDLCD_REG_COMMAND, 1);
> > > +	drm_crtc_vblank_on(crtc);
> > > +}
> > > +
> > > +static void hdlcd_crtc_disable(struct drm_crtc *crtc)
> > > +{
> > > +	struct hdlcd_drm_private *hdlcd = crtc_to_hdlcd_priv(crtc);
> > > +
> > > +	if (!crtc->primary->fb)
> > > +		return;
> > > +
> > > +	clk_disable_unprepare(hdlcd->clk);
> > > +	hdlcd_write(hdlcd, HDLCD_REG_COMMAND, 0);
> > > +	drm_crtc_vblank_off(crtc);
> > > +}
> > > +
> > > +static int hdlcd_crtc_atomic_check(struct drm_crtc *crtc,
> > > +				   struct drm_crtc_state *state)
> > > +{
> > > +	struct hdlcd_drm_private *hdlcd = crtc_to_hdlcd_priv(crtc);
> > > +	struct drm_display_mode *mode = &state->adjusted_mode;
> > > +	long rate, clk_rate = mode->clock * 1000;
> > > +
> > > +	rate = clk_round_rate(hdlcd->clk, clk_rate);
> > > +	if (rate != clk_rate) {
> > > +		/* clock required by mode not supported by hardware */
> > > +		return -EINVAL;
> > > +	}
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static void hdlcd_crtc_atomic_begin(struct drm_crtc *crtc,
> > > +				    struct drm_crtc_state *state)
> > > +{
> > > +	struct hdlcd_drm_private *hdlcd = crtc_to_hdlcd_priv(crtc);
> > > +	unsigned long flags;
> > > +
> > > +	if (crtc->state->event) {
> > > +		crtc->state->event->pipe = drm_crtc_index(crtc);
> > > +
> > > +		WARN_ON(drm_crtc_vblank_get(crtc) != 0);
> > > +
> > > +		spin_lock_irqsave(&crtc->dev->event_lock, flags);
> > > +		hdlcd->event = crtc->state->event;
> > > +		spin_unlock_irqrestore(&crtc->dev->event_lock, flags);
> > > +		crtc->state->event = NULL;
> > > +	}
> > > +}
> > > +
> > > +static void hdlcd_crtc_atomic_flush(struct drm_crtc *crtc,
> > > +				    struct drm_crtc_state *state)
> > > +{
> > > +}
> > > +
> > > +static bool hdlcd_crtc_mode_fixup(struct drm_crtc *crtc,
> > > +			const struct drm_display_mode *mode,
> > > +			struct drm_display_mode *adjusted_mode)
> > > +{
> > > +	return true;
> > > +}
> > > +
> > > +static const struct drm_crtc_helper_funcs hdlcd_crtc_helper_funcs = {
> > > +	.mode_fixup	= hdlcd_crtc_mode_fixup,
> > > +	.mode_set	= drm_helper_crtc_mode_set,
> > > +	.mode_set_base	= drm_helper_crtc_mode_set_base,
> > > +	.mode_set_nofb	= hdlcd_crtc_mode_set_nofb,
> > > +	.enable		= hdlcd_crtc_enable,
> > > +	.disable	= hdlcd_crtc_disable,
> > > +	.prepare	= hdlcd_crtc_disable,
> > > +	.commit		= hdlcd_crtc_enable,
> > > +	.atomic_check	= hdlcd_crtc_atomic_check,
> > > +	.atomic_begin	= hdlcd_crtc_atomic_begin,
> > > +	.atomic_flush	= hdlcd_crtc_atomic_flush,
> > > +};
> > > +
> > > +static int hdlcd_plane_atomic_check(struct drm_plane *plane,
> > > +				    struct drm_plane_state *state)
> > > +{
> > > +	return 0;
> > > +}
> > > +
> > > +static void hdlcd_plane_atomic_update(struct drm_plane *plane,
> > > +				      struct drm_plane_state *state)
> > > +{
> > > +	struct hdlcd_drm_private *hdlcd;
> > > +	struct drm_gem_cma_object *gem;
> > > +	dma_addr_t scanout_start;
> > > +
> > > +	if (!plane->state->crtc || !plane->state->fb)
> > > +		return;
> > > +
> > > +	hdlcd = crtc_to_hdlcd_priv(plane->state->crtc);
> > > +	gem = drm_fb_cma_get_gem_obj(plane->state->fb, 0);
> > > +	scanout_start = gem->paddr;
> > > +	hdlcd_write(hdlcd, HDLCD_REG_FB_BASE, scanout_start);
> > > +}
> > > +
> > > +static const struct drm_plane_helper_funcs hdlcd_plane_helper_funcs = {
> > > +	.prepare_fb = NULL,
> > > +	.cleanup_fb = NULL,
> > > +	.atomic_check = hdlcd_plane_atomic_check,
> > > +	.atomic_update = hdlcd_plane_atomic_update,
> > > +};
> > > +
> > > +static void hdlcd_plane_destroy(struct drm_plane *plane)
> > > +{
> > > +	drm_plane_helper_disable(plane);
> > > +	drm_plane_cleanup(plane);
> > > +}
> > > +
> > > +static const struct drm_plane_funcs hdlcd_plane_funcs = {
> > > +	.update_plane		= drm_atomic_helper_update_plane,
> > > +	.disable_plane		= drm_atomic_helper_disable_plane,
> > > +	.destroy		= hdlcd_plane_destroy,
> > > +	.reset			= drm_atomic_helper_plane_reset,
> > > +	.atomic_duplicate_state = drm_atomic_helper_plane_duplicate_state,
> > > +	.atomic_destroy_state	= drm_atomic_helper_plane_destroy_state,
> > > +};
> > > +
> > > +static struct drm_plane *hdlcd_plane_init(struct drm_device *drm)
> > > +{
> > > +	struct hdlcd_drm_private *hdlcd = drm->dev_private;
> > > +	struct drm_plane *plane = NULL;
> > > +	u32 formats[ARRAY_SIZE(supported_formats)], i;
> > > +	int ret;
> > > +
> > > +	plane = devm_kzalloc(drm->dev, sizeof(*plane), GFP_KERNEL);
> > > +	if (!plane)
> > > +		return ERR_PTR(-ENOMEM);
> > > +
> > > +	for (i = 0; i < ARRAY_SIZE(supported_formats); i++)
> > > +		formats[i] = supported_formats[i].fourcc;
> > > +
> > > +	ret = drm_universal_plane_init(drm, plane, 0xff, &hdlcd_plane_funcs,
> > > +				       formats, ARRAY_SIZE(formats),
> > > +				       DRM_PLANE_TYPE_PRIMARY);
> > > +	if (ret) {
> > > +		devm_kfree(drm->dev, plane);
> > > +		return ERR_PTR(ret);
> > > +	}
> > > +
> > > +	drm_plane_helper_add(plane, &hdlcd_plane_helper_funcs);
> > > +	hdlcd->plane = plane;
> > > +
> > > +	return plane;
> > > +}
> > > +
> > > +void hdlcd_crtc_suspend(struct drm_crtc *crtc)
> > > +{
> > > +	hdlcd_crtc_disable(crtc);
> > > +}
> > > +
> > > +void hdlcd_crtc_resume(struct drm_crtc *crtc)
> > > +{
> > > +	hdlcd_crtc_enable(crtc);
> > > +}
> > > +
> > > +int hdlcd_setup_crtc(struct drm_device *drm)
> > > +{
> > > +	struct hdlcd_drm_private *hdlcd = drm->dev_private;
> > > +	struct drm_plane *primary;
> > > +	int ret;
> > > +
> > > +	primary = hdlcd_plane_init(drm);
> > > +	if (IS_ERR(primary))
> > > +		return PTR_ERR(primary);
> > > +
> > > +	ret = drm_crtc_init_with_planes(drm, &hdlcd->crtc, primary, NULL,
> > > +					&hdlcd_crtc_funcs);
> > > +	if (ret) {
> > > +		hdlcd_plane_destroy(primary);
> > > +		devm_kfree(drm->dev, primary);
> > > +		return ret;
> > > +	}
> > > +
> > > +	drm_crtc_helper_add(&hdlcd->crtc, &hdlcd_crtc_helper_funcs);
> > > +	return 0;
> > > +}
> > > diff --git a/drivers/gpu/drm/arm/hdlcd_drv.c b/drivers/gpu/drm/arm/hdlcd_drv.c
> > > new file mode 100644
> > > index 0000000..45440b1
> > > --- /dev/null
> > > +++ b/drivers/gpu/drm/arm/hdlcd_drv.c
> > > @@ -0,0 +1,555 @@
> > > +/*
> > > + * Copyright (C) 2013-2015 ARM Limited
> > > + * Author: Liviu Dudau <Liviu.Dudau@arm.com>
> > > + *
> > > + * This file is subject to the terms and conditions of the GNU General Public
> > > + * License.  See the file COPYING in the main directory of this archive
> > > + * for more details.
> > > + *
> > > + *  ARM HDLCD Driver
> > > + */
> > > +
> > > +#include <linux/module.h>
> > > +#include <linux/spinlock.h>
> > > +#include <linux/clk.h>
> > > +#include <linux/component.h>
> > > +#include <linux/of_graph.h>
> > > +#include <linux/of_reserved_mem.h>
> > > +#include <linux/pm_runtime.h>
> > > +
> > > +#include <drm/drmP.h>
> > > +#include <drm/drm_atomic_helper.h>
> > > +#include <drm/drm_crtc.h>
> > > +#include <drm/drm_crtc_helper.h>
> > > +#include <drm/drm_fb_helper.h>
> > > +#include <drm/drm_fb_cma_helper.h>
> > > +#include <drm/drm_gem_cma_helper.h>
> > > +#include <drm/drm_of.h>
> > > +
> > > +#include "hdlcd_drv.h"
> > > +#include "hdlcd_regs.h"
> > > +
> > > +static int compare_dev(struct device *dev, void *data)
> > > +{
> > > +	return dev->of_node == data;
> > > +}
> > > +
> > > +static int hdlcd_load(struct drm_device *drm, unsigned long flags)
> > > +{
> > > +	struct hdlcd_drm_private *hdlcd = drm->dev_private;
> > > +	struct platform_device *pdev = to_platform_device(drm->dev);
> > > +	struct resource *res;
> > > +	u32 version;
> > > +	int ret;
> > > +
> > > +	hdlcd->clk = devm_clk_get(drm->dev, "pxlclk");
> > > +	if (IS_ERR(hdlcd->clk))
> > > +		return PTR_ERR(hdlcd->clk);
> > > +
> > > +#ifdef CONFIG_DEBUG_FS
> > > +	atomic_set(&hdlcd->buffer_underrun_count, 0);
> > > +	atomic_set(&hdlcd->bus_error_count, 0);
> > > +	atomic_set(&hdlcd->vsync_count, 0);
> > > +	atomic_set(&hdlcd->dma_end_count, 0);
> > > +#endif
> > > +
> > > +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > > +	hdlcd->mmio = devm_ioremap_resource(drm->dev, res);
> > > +	if (IS_ERR(hdlcd->mmio)) {
> > > +		DRM_ERROR("failed to map control registers area\n");
> > > +		ret = PTR_ERR(hdlcd->mmio);
> > > +		hdlcd->mmio = NULL;
> > > +		goto fail;
> > > +	}
> > > +
> > > +	version = hdlcd_read(hdlcd, HDLCD_REG_VERSION);
> > > +	if ((version & HDLCD_PRODUCT_MASK) != HDLCD_PRODUCT_ID) {
> > > +		DRM_ERROR("unknown product id: 0x%x\n", version);
> > > +		ret = -EINVAL;
> > > +		goto fail;
> > > +	}
> > > +	DRM_INFO("found ARM HDLCD version r%dp%d\n",
> > > +		(version & HDLCD_VERSION_MAJOR_MASK) >> 8,
> > > +		version & HDLCD_VERSION_MINOR_MASK);
> > > +
> > > +	/* Get the optional framebuffer memory resource */
> > > +	ret = of_reserved_mem_device_init(drm->dev);
> > > +	if (ret && ret != -ENODEV)
> > > +		goto fail;
> > > +
> > > +	ret = dma_set_mask_and_coherent(drm->dev, DMA_BIT_MASK(32));
> > > +	if (ret)
> > > +		goto setup_fail;
> > > +
> > > +	ret = hdlcd_setup_crtc(drm);
> > > +	if (ret < 0) {
> > > +		DRM_ERROR("failed to create crtc\n");
> > > +		goto setup_fail;
> > > +	}
> > > +
> > > +	pm_runtime_enable(drm->dev);
> > > +
> > > +	pm_runtime_get_sync(drm->dev);
> > > +	ret = drm_irq_install(drm, platform_get_irq(pdev, 0));
> > > +	pm_runtime_put_sync(drm->dev);
> > > +	if (ret < 0) {
> > > +		DRM_ERROR("failed to install IRQ handler\n");
> > > +		goto irq_fail;
> > > +	}
> > > +
> > > +	return 0;
> > > +
> > > +irq_fail:
> > > +	drm_crtc_cleanup(&hdlcd->crtc);
> > > +setup_fail:
> > > +	of_reserved_mem_device_release(drm->dev);
> > > +fail:
> > > +	devm_clk_put(drm->dev, hdlcd->clk);
> > > +
> > > +	return ret;
> > > +}
> > > +
> > > +static void hdlcd_fb_output_poll_changed(struct drm_device *drm)
> > > +{
> > > +	struct hdlcd_drm_private *hdlcd = drm->dev_private;
> > > +
> > > +	if (hdlcd->fbdev) {
> > > +		drm_fbdev_cma_hotplug_event(hdlcd->fbdev);
> > > +	}
> > > +}
> > > +
> > > +static const struct drm_mode_config_funcs hdlcd_mode_config_funcs = {
> > > +	.fb_create = drm_fb_cma_create,
> > > +	.output_poll_changed = hdlcd_fb_output_poll_changed,
> > > +	.atomic_check = drm_atomic_helper_check,
> > > +	.atomic_commit = drm_atomic_helper_commit,
> > > +};
> > > +
> > > +static void hdlcd_setup_mode_config(struct drm_device *drm)
> > > +{
> > > +	drm_mode_config_init(drm);
> > > +	drm->mode_config.min_width = 0;
> > > +	drm->mode_config.min_height = 0;
> > > +	drm->mode_config.max_width = HDLCD_MAX_XRES;
> > > +	drm->mode_config.max_height = HDLCD_MAX_YRES;
> > > +	drm->mode_config.funcs = &hdlcd_mode_config_funcs;
> > > +}
> > > +
> > > +static void hdlcd_preclose(struct drm_device *drm, struct drm_file *file)
> > > +{
> > > +}
> > > +
> > > +static void hdlcd_lastclose(struct drm_device *drm)
> > > +{
> > > +	struct hdlcd_drm_private *hdlcd = drm->dev_private;
> > > +
> > > +	drm_fbdev_cma_restore_mode(hdlcd->fbdev);
> > > +}
> > > +
> > > +static irqreturn_t hdlcd_irq(int irq, void *arg)
> > > +{
> > > +	struct drm_device *drm = arg;
> > > +	struct hdlcd_drm_private *hdlcd = drm->dev_private;
> > > +	unsigned long irq_status;
> > > +
> > > +	irq_status = hdlcd_read(hdlcd, HDLCD_REG_INT_STATUS);
> > > +
> > > +#ifdef CONFIG_DEBUG_FS
> > > +	if (irq_status & HDLCD_INTERRUPT_UNDERRUN) {
> > > +		atomic_inc(&hdlcd->buffer_underrun_count);
> > > +	}
> > > +	if (irq_status & HDLCD_INTERRUPT_DMA_END) {
> > > +		atomic_inc(&hdlcd->dma_end_count);
> > > +	}
> > > +	if (irq_status & HDLCD_INTERRUPT_BUS_ERROR) {
> > > +		atomic_inc(&hdlcd->bus_error_count);
> > > +	}
> > > +	if (irq_status & HDLCD_INTERRUPT_VSYNC) {
> > > +		atomic_inc(&hdlcd->vsync_count);
> > > +	}
> > > +#endif
> > > +	if (irq_status & HDLCD_INTERRUPT_VSYNC) {
> > > +		unsigned long flags;
> > > +
> > > +		drm_handle_vblank(drm, 0);
> > 
> > We have drm_crtc_ versions for this one ...
> > > +
> > > +		spin_lock_irqsave(&drm->event_lock, flags);
> > > +		if (hdlcd->event) {
> > > +			drm_send_vblank_event(drm, hdlcd->event->pipe, hdlcd->event);
> > 
> > and this one now too. New drivers shouldn't need to deal with the opaque
> > int pipe stuff any more on the caller sides, and real soon (hopefully)
> > we'll have hooks for the vblank stuff that take struct drm_crtc * too.
> > 
> > I've quickly scrolled through the driver otherwise and didn't notice
> > anything else that should be updated to latest practices. Looks really
> > good.
> > -Daniel
> > 
> > > +			drm_crtc_vblank_put(&hdlcd->crtc);
> > > +			hdlcd->event = NULL;
> > > +		}
> > > +		spin_unlock_irqrestore(&drm->event_lock, flags);
> > > +	}
> > > +
> > > +	/* acknowledge interrupt(s) */
> > > +	hdlcd_write(hdlcd, HDLCD_REG_INT_CLEAR, irq_status);
> > > +
> > > +	return IRQ_HANDLED;
> > > +}
> > > +
> > > +static void hdlcd_irq_preinstall(struct drm_device *drm)
> > > +{
> > > +	struct hdlcd_drm_private *hdlcd = drm->dev_private;
> > > +	/* Ensure interrupts are disabled */
> > > +	hdlcd_write(hdlcd, HDLCD_REG_INT_MASK, 0);
> > > +	hdlcd_write(hdlcd, HDLCD_REG_INT_CLEAR, ~0);
> > > +}
> > > +
> > > +static int hdlcd_irq_postinstall(struct drm_device *drm)
> > > +{
> > > +#ifdef CONFIG_DEBUG_FS
> > > +	struct hdlcd_drm_private *hdlcd = drm->dev_private;
> > > +	unsigned long irq_mask = hdlcd_read(hdlcd, HDLCD_REG_INT_MASK);
> > > +
> > > +	/* enable debug interrupts */
> > > +	irq_mask |= HDLCD_DEBUG_INT_MASK;
> > > +
> > > +	hdlcd_write(hdlcd, HDLCD_REG_INT_MASK, irq_mask);
> > > +#endif
> > > +	return 0;
> > > +}
> > > +
> > > +static void hdlcd_irq_uninstall(struct drm_device *drm)
> > > +{
> > > +	struct hdlcd_drm_private *hdlcd = drm->dev_private;
> > > +	/* disable all the interrupts that we might have enabled */
> > > +	unsigned long irq_mask = hdlcd_read(hdlcd, HDLCD_REG_INT_MASK);
> > > +
> > > +#ifdef CONFIG_DEBUG_FS
> > > +	/* disable debug interrupts */
> > > +	irq_mask &= ~HDLCD_DEBUG_INT_MASK;
> > > +#endif
> > > +
> > > +	/* disable vsync interrupts */
> > > +	irq_mask &= ~HDLCD_INTERRUPT_VSYNC;
> > > +
> > > +	hdlcd_write(hdlcd, HDLCD_REG_INT_MASK, irq_mask);
> > > +}
> > > +
> > > +static int hdlcd_enable_vblank(struct drm_device *drm, unsigned int crtc)
> > > +{
> > > +	struct hdlcd_drm_private *hdlcd = drm->dev_private;
> > > +	unsigned int mask = hdlcd_read(hdlcd, HDLCD_REG_INT_MASK);
> > > +
> > > +	hdlcd_write(hdlcd, HDLCD_REG_INT_MASK, mask | HDLCD_INTERRUPT_VSYNC);
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static void hdlcd_disable_vblank(struct drm_device *drm, unsigned int crtc)
> > > +{
> > > +	struct hdlcd_drm_private *hdlcd = drm->dev_private;
> > > +	unsigned int mask = hdlcd_read(hdlcd, HDLCD_REG_INT_MASK);
> > > +
> > > +	hdlcd_write(hdlcd, HDLCD_REG_INT_MASK, mask & ~HDLCD_INTERRUPT_VSYNC);
> > > +}
> > > +
> > > +#ifdef CONFIG_DEBUG_FS
> > > +static int hdlcd_show_underrun_count(struct seq_file *m, void *arg)
> > > +{
> > > +	struct drm_info_node *node = (struct drm_info_node *)m->private;
> > > +	struct drm_device *drm = node->minor->dev;
> > > +	struct hdlcd_drm_private *hdlcd = drm->dev_private;
> > > +
> > > +	seq_printf(m, "underrun : %d\n", atomic_read(&hdlcd->buffer_underrun_count));
> > > +	seq_printf(m, "dma_end  : %d\n", atomic_read(&hdlcd->dma_end_count));
> > > +	seq_printf(m, "bus_error: %d\n", atomic_read(&hdlcd->bus_error_count));
> > > +	seq_printf(m, "vsync    : %d\n", atomic_read(&hdlcd->vsync_count));
> > > +	return 0;
> > > +}
> > > +
> > > +static int hdlcd_show_pxlclock(struct seq_file *m, void *arg)
> > > +{
> > > +	struct drm_info_node *node = (struct drm_info_node *)m->private;
> > > +	struct drm_device *drm = node->minor->dev;
> > > +	struct hdlcd_drm_private *hdlcd = drm->dev_private;
> > > +	unsigned long clkrate = clk_get_rate(hdlcd->clk);
> > > +	unsigned long mode_clock = hdlcd->crtc.mode.crtc_clock * 1000;
> > > +
> > > +	seq_printf(m, "hw  : %lu\n", clkrate);
> > > +	seq_printf(m, "mode: %lu\n", mode_clock);
> > > +	return 0;
> > > +}
> > > +
> > > +static struct drm_info_list hdlcd_debugfs_list[] = {
> > > +	{ "interrupt_count", hdlcd_show_underrun_count, 0 },
> > > +	{ "clocks", hdlcd_show_pxlclock, 0 },
> > > +};
> > > +
> > > +static int hdlcd_debugfs_init(struct drm_minor *minor)
> > > +{
> > > +	return drm_debugfs_create_files(hdlcd_debugfs_list,
> > > +		ARRAY_SIZE(hdlcd_debugfs_list),	minor->debugfs_root, minor);
> > > +}
> > > +
> > > +static void hdlcd_debugfs_cleanup(struct drm_minor *minor)
> > > +{
> > > +	drm_debugfs_remove_files(hdlcd_debugfs_list,
> > > +		ARRAY_SIZE(hdlcd_debugfs_list), minor);
> > > +}
> > > +#endif
> > > +
> > > +static const struct file_operations fops = {
> > > +	.owner		= THIS_MODULE,
> > > +	.open		= drm_open,
> > > +	.release	= drm_release,
> > > +	.unlocked_ioctl	= drm_ioctl,
> > > +#ifdef CONFIG_COMPAT
> > > +	.compat_ioctl	= drm_compat_ioctl,
> > > +#endif
> > > +	.poll		= drm_poll,
> > > +	.read		= drm_read,
> > > +	.llseek		= noop_llseek,
> > > +	.mmap		= drm_gem_cma_mmap,
> > > +};
> > > +
> > > +static struct drm_driver hdlcd_driver = {
> > > +	.driver_features = DRIVER_HAVE_IRQ | DRIVER_GEM |
> > > +			   DRIVER_MODESET | DRIVER_PRIME |
> > > +			   DRIVER_ATOMIC,
> > > +	.preclose = hdlcd_preclose,
> > > +	.lastclose = hdlcd_lastclose,
> > > +	.irq_handler = hdlcd_irq,
> > > +	.irq_preinstall = hdlcd_irq_preinstall,
> > > +	.irq_postinstall = hdlcd_irq_postinstall,
> > > +	.irq_uninstall = hdlcd_irq_uninstall,
> > > +	.get_vblank_counter = drm_vblank_no_hw_counter,
> > > +	.enable_vblank = hdlcd_enable_vblank,
> > > +	.disable_vblank = hdlcd_disable_vblank,
> > > +	.gem_free_object = drm_gem_cma_free_object,
> > > +	.gem_vm_ops = &drm_gem_cma_vm_ops,
> > > +	.dumb_create = drm_gem_cma_dumb_create,
> > > +	.dumb_map_offset = drm_gem_cma_dumb_map_offset,
> > > +	.dumb_destroy = drm_gem_dumb_destroy,
> > > +	.prime_handle_to_fd = drm_gem_prime_handle_to_fd,
> > > +	.prime_fd_to_handle = drm_gem_prime_fd_to_handle,
> > > +	.gem_prime_export = drm_gem_prime_export,
> > > +	.gem_prime_import = drm_gem_prime_import,
> > > +	.gem_prime_get_sg_table = drm_gem_cma_prime_get_sg_table,
> > > +	.gem_prime_import_sg_table = drm_gem_cma_prime_import_sg_table,
> > > +	.gem_prime_vmap = drm_gem_cma_prime_vmap,
> > > +	.gem_prime_vunmap = drm_gem_cma_prime_vunmap,
> > > +	.gem_prime_mmap = drm_gem_cma_prime_mmap,
> > > +#ifdef CONFIG_DEBUG_FS
> > > +	.debugfs_init = hdlcd_debugfs_init,
> > > +	.debugfs_cleanup = hdlcd_debugfs_cleanup,
> > > +#endif
> > > +	.fops = &fops,
> > > +	.name = "hdlcd",
> > > +	.desc = "ARM HDLCD Controller DRM",
> > > +	.date = "20151021",
> > > +	.major = 1,
> > > +	.minor = 0,
> > > +};
> > > +
> > > +static int hdlcd_add_components(struct device *dev, struct master *master)
> > > +{
> > > +	struct device_node *port, *ep = NULL;
> > > +	int ret = -ENXIO;
> > > +
> > > +	if (!dev->of_node)
> > > +		return -ENODEV;
> > > +
> > > +	do {
> > > +		ep = of_graph_get_next_endpoint(dev->of_node, ep);
> > > +		if (!ep)
> > > +			break;
> > > +
> > > +		if (!of_device_is_available(ep)) {
> > > +			of_node_put(ep);
> > > +			continue;
> > > +		}
> > > +
> > > +		port = of_graph_get_remote_port_parent(ep);
> > > +		of_node_put(ep);
> > > +		if (!port || !of_device_is_available(port)) {
> > > +			of_node_put(port);
> > > +			continue;
> > > +		}
> > > +
> > > +		ret = component_master_add_child(master, compare_dev, port);
> > > +		of_node_put(port);
> > > +	} while (1);
> > > +
> > > +	return ret;
> > > +}
> > > +
> > > +static int hdlcd_drm_bind(struct device *dev)
> > > +{
> > > +	struct drm_device *drm;
> > > +	struct hdlcd_drm_private *hdlcd;
> > > +	int ret;
> > > +
> > > +	hdlcd = devm_kzalloc(dev, sizeof(*hdlcd), GFP_KERNEL);
> > > +	if (!hdlcd)
> > > +		return -ENOMEM;
> > > +
> > > +	drm = drm_dev_alloc(&hdlcd_driver, dev);
> > > +	if (!drm)
> > > +		return -ENOMEM;
> > > +
> > > +	drm->dev_private = hdlcd;
> > > +
> > > +	ret = drm_dev_set_unique(drm, "%s", dev_name(dev));
> > > +	if (ret)
> > > +		goto err_free;
> > > +
> > > +	hdlcd_setup_mode_config(drm);
> > > +
> > > +	ret = hdlcd_load(drm, 0);
> > > +	if (ret)
> > > +		goto err_free;
> > > +
> > > +	ret = drm_dev_register(drm, 0);
> > > +	if (ret)
> > > +		goto err_unload;
> > > +
> > > +	dev_set_drvdata(dev, drm);
> > > +
> > > +	ret = component_bind_all(dev, drm);
> > > +	if (ret) {
> > > +		DRM_ERROR("Failed to bind all components\n");
> > > +		goto err_unregister;
> > > +	}
> > > +
> > > +	ret = drm_vblank_init(drm, drm->mode_config.num_crtc);
> > > +	if (ret < 0) {
> > > +		DRM_ERROR("failed to initialise vblank\n");
> > > +		goto err_vblank;
> > > +	}
> > > +	drm->vblank_disable_allowed = true;
> > > +
> > > +	drm_mode_config_reset(drm);
> > > +	drm_kms_helper_poll_init(drm);
> > > +
> > > +	hdlcd->fbdev = drm_fbdev_cma_init(drm, 32, drm->mode_config.num_crtc,
> > > +					  drm->mode_config.num_connector);
> > > +
> > > +	if (IS_ERR(hdlcd->fbdev)) {
> > > +		ret = PTR_ERR(hdlcd->fbdev);
> > > +		hdlcd->fbdev = NULL;
> > > +		goto err_fbdev;
> > > +	}
> > > +
> > > +	return 0;
> > > +
> > > +err_fbdev:
> > > +	drm_kms_helper_poll_fini(drm);
> > > +	drm_mode_config_cleanup(drm);
> > > +	drm_vblank_cleanup(drm);
> > > +err_vblank:
> > > +	component_unbind_all(dev, drm);
> > > +err_unregister:
> > > +	drm_dev_unregister(drm);
> > > +err_unload:
> > > +	pm_runtime_get_sync(drm->dev);
> > > +	drm_irq_uninstall(drm);
> > > +	pm_runtime_put_sync(drm->dev);
> > > +	pm_runtime_disable(drm->dev);
> > > +	of_reserved_mem_device_release(drm->dev);
> > > +	devm_clk_put(dev, hdlcd->clk);
> > > +err_free:
> > > +	drm_dev_unref(drm);
> > > +
> > > +	return ret;
> > > +}
> > > +
> > > +static void hdlcd_drm_unbind(struct device *dev)
> > > +{
> > > +	struct drm_device *drm = dev_get_drvdata(dev);
> > > +	struct hdlcd_drm_private *hdlcd = drm->dev_private;
> > > +
> > > +	if (hdlcd->fbdev) {
> > > +		drm_fbdev_cma_fini(hdlcd->fbdev);
> > > +		hdlcd->fbdev = NULL;
> > > +	}
> > > +	drm_kms_helper_poll_fini(drm);
> > > +	component_unbind_all(dev, drm);
> > > +	drm_vblank_cleanup(drm);
> > > +	pm_runtime_get_sync(drm->dev);
> > > +	drm_irq_uninstall(drm);
> > > +	pm_runtime_put_sync(drm->dev);
> > > +	pm_runtime_disable(drm->dev);
> > > +	of_reserved_mem_device_release(drm->dev);
> > > +	if (!IS_ERR(hdlcd->clk)) {
> > > +		devm_clk_put(drm->dev, hdlcd->clk);
> > > +		hdlcd->clk = NULL;
> > > +	}
> > > +	drm_mode_config_cleanup(drm);
> > > +	drm_dev_unregister(drm);
> > > +	drm_dev_unref(drm);
> > > +	drm->dev_private = NULL;
> > > +	dev_set_drvdata(dev, NULL);
> > > +}
> > > +
> > > +static const struct component_master_ops hdlcd_master_ops = {
> > > +	.add_components	= hdlcd_add_components,
> > > +	.bind		= hdlcd_drm_bind,
> > > +	.unbind		= hdlcd_drm_unbind,
> > > +};
> > > +
> > > +static int hdlcd_probe(struct platform_device *pdev)
> > > +{
> > > +	return component_master_add(&pdev->dev, &hdlcd_master_ops);
> > > +}
> > > +
> > > +static int hdlcd_remove(struct platform_device *pdev)
> > > +{
> > > +	component_master_del(&pdev->dev, &hdlcd_master_ops);
> > > +	return 0;
> > > +}
> > > +
> > > +static const struct of_device_id  hdlcd_of_match[] = {
> > > +	{ .compatible	= "arm,hdlcd" },
> > > +	{},
> > > +};
> > > +MODULE_DEVICE_TABLE(of, hdlcd_of_match);
> > > +
> > > +static int hdlcd_pm_suspend(struct device *dev)
> > > +{
> > > +	struct drm_device *drm = dev_get_drvdata(dev);
> > > +	struct drm_crtc *crtc;
> > > +
> > > +	if (pm_runtime_suspended(dev))
> > > +		return 0;
> > > +
> > > +	drm_modeset_lock_all(drm);
> > > +	list_for_each_entry(crtc, &drm->mode_config.crtc_list, head)
> > > +		hdlcd_crtc_suspend(crtc);
> > > +	drm_modeset_unlock_all(drm);
> > > +	return 0;
> > > +}
> > > +
> > > +static int hdlcd_pm_resume(struct device *dev)
> > > +{
> > > +	struct drm_device *drm = dev_get_drvdata(dev);
> > > +	struct drm_crtc *crtc;
> > > +
> > > +	if (!pm_runtime_suspended(dev))
> > > +		return 0;
> > > +
> > > +	drm_modeset_lock_all(drm);
> > > +	list_for_each_entry(crtc, &drm->mode_config.crtc_list, head)
> > > +		hdlcd_crtc_resume(crtc);
> > > +	drm_modeset_unlock_all(drm);
> > > +	return 0;
> > > +}
> > > +
> > > +static SIMPLE_DEV_PM_OPS(hdlcd_pm_ops, hdlcd_pm_suspend, hdlcd_pm_resume);
> > > +
> > > +static struct platform_driver hdlcd_platform_driver = {
> > > +	.probe		= hdlcd_probe,
> > > +	.remove		= hdlcd_remove,
> > > +	.driver	= {
> > > +		.name = "hdlcd",
> > > +		.pm = &hdlcd_pm_ops,
> > > +		.of_match_table	= hdlcd_of_match,
> > > +	},
> > > +};
> > > +
> > > +module_platform_driver(hdlcd_platform_driver);
> > > +
> > > +MODULE_AUTHOR("Liviu Dudau");
> > > +MODULE_DESCRIPTION("ARM HDLCD DRM driver");
> > > +MODULE_LICENSE("GPL v2");
> > > diff --git a/drivers/gpu/drm/arm/hdlcd_drv.h b/drivers/gpu/drm/arm/hdlcd_drv.h
> > > new file mode 100644
> > > index 0000000..f2eedfb
> > > --- /dev/null
> > > +++ b/drivers/gpu/drm/arm/hdlcd_drv.h
> > > @@ -0,0 +1,42 @@
> > > +/*
> > > + *  ARM HDLCD Controller register definition
> > > + */
> > > +
> > > +#ifndef __HDLCD_DRV_H__
> > > +#define __HDLCD_DRV_H__
> > > +
> > > +struct hdlcd_drm_private {
> > > +	void __iomem			*mmio;
> > > +	struct clk			*clk;
> > > +	struct drm_fbdev_cma		*fbdev;
> > > +	struct drm_framebuffer		*fb;
> > > +	struct drm_pending_vblank_event	*event;
> > > +	struct drm_crtc			crtc;
> > > +	struct drm_plane		*plane;
> > > +#ifdef CONFIG_DEBUG_FS
> > > +	atomic_t buffer_underrun_count;
> > > +	atomic_t bus_error_count;
> > > +	atomic_t vsync_count;
> > > +	atomic_t dma_end_count;
> > > +#endif
> > > +};
> > > +
> > > +#define crtc_to_hdlcd_priv(x)	container_of(x, struct hdlcd_drm_private, crtc)
> > > +
> > > +static inline void hdlcd_write(struct hdlcd_drm_private *hdlcd,
> > > +			       unsigned int reg, u32 value)
> > > +{
> > > +	writel(value, hdlcd->mmio + reg);
> > > +}
> > > +
> > > +static inline u32 hdlcd_read(struct hdlcd_drm_private *hdlcd, unsigned int reg)
> > > +{
> > > +	return readl(hdlcd->mmio + reg);
> > > +}
> > > +
> > > +int hdlcd_setup_crtc(struct drm_device *dev);
> > > +void hdlcd_set_scanout(struct hdlcd_drm_private *hdlcd);
> > > +void hdlcd_crtc_suspend(struct drm_crtc *crtc);
> > > +void hdlcd_crtc_resume(struct drm_crtc *crtc);
> > > +
> > > +#endif /* __HDLCD_DRV_H__ */
> > > diff --git a/drivers/gpu/drm/arm/hdlcd_regs.h b/drivers/gpu/drm/arm/hdlcd_regs.h
> > > new file mode 100644
> > > index 0000000..66799eb
> > > --- /dev/null
> > > +++ b/drivers/gpu/drm/arm/hdlcd_regs.h
> > > @@ -0,0 +1,87 @@
> > > +/*
> > > + * Copyright (C) 2013,2014 ARM Limited
> > > + *
> > > + * This file is subject to the terms and conditions of the GNU General Public
> > > + * License.  See the file COPYING in the main directory of this archive
> > > + * for more details.
> > > + *
> > > + *  ARM HDLCD Controller register definition
> > > + */
> > > +
> > > +#ifndef __HDLCD_REGS_H__
> > > +#define __HDLCD_REGS_H__
> > > +
> > > +/* register offsets */
> > > +#define HDLCD_REG_VERSION		0x0000	/* ro */
> > > +#define HDLCD_REG_INT_RAWSTAT		0x0010	/* rw */
> > > +#define HDLCD_REG_INT_CLEAR		0x0014	/* wo */
> > > +#define HDLCD_REG_INT_MASK		0x0018	/* rw */
> > > +#define HDLCD_REG_INT_STATUS		0x001c	/* ro */
> > > +#define HDLCD_REG_FB_BASE		0x0100	/* rw */
> > > +#define HDLCD_REG_FB_LINE_LENGTH	0x0104	/* rw */
> > > +#define HDLCD_REG_FB_LINE_COUNT		0x0108	/* rw */
> > > +#define HDLCD_REG_FB_LINE_PITCH		0x010c	/* rw */
> > > +#define HDLCD_REG_BUS_OPTIONS		0x0110	/* rw */
> > > +#define HDLCD_REG_V_SYNC		0x0200	/* rw */
> > > +#define HDLCD_REG_V_BACK_PORCH		0x0204	/* rw */
> > > +#define HDLCD_REG_V_DATA		0x0208	/* rw */
> > > +#define HDLCD_REG_V_FRONT_PORCH		0x020c	/* rw */
> > > +#define HDLCD_REG_H_SYNC		0x0210	/* rw */
> > > +#define HDLCD_REG_H_BACK_PORCH		0x0214	/* rw */
> > > +#define HDLCD_REG_H_DATA		0x0218	/* rw */
> > > +#define HDLCD_REG_H_FRONT_PORCH		0x021c	/* rw */
> > > +#define HDLCD_REG_POLARITIES		0x0220	/* rw */
> > > +#define HDLCD_REG_COMMAND		0x0230	/* rw */
> > > +#define HDLCD_REG_PIXEL_FORMAT		0x0240	/* rw */
> > > +#define HDLCD_REG_RED_SELECT		0x0244	/* rw */
> > > +#define HDLCD_REG_GREEN_SELECT		0x0248	/* rw */
> > > +#define HDLCD_REG_BLUE_SELECT		0x024c	/* rw */
> > > +
> > > +/* version */
> > > +#define HDLCD_PRODUCT_ID		0x1CDC0000
> > > +#define HDLCD_PRODUCT_MASK		0xFFFF0000
> > > +#define HDLCD_VERSION_MAJOR_MASK	0x0000FF00
> > > +#define HDLCD_VERSION_MINOR_MASK	0x000000FF
> > > +
> > > +/* interrupts */
> > > +#define HDLCD_INTERRUPT_DMA_END		(1 << 0)
> > > +#define HDLCD_INTERRUPT_BUS_ERROR	(1 << 1)
> > > +#define HDLCD_INTERRUPT_VSYNC		(1 << 2)
> > > +#define HDLCD_INTERRUPT_UNDERRUN	(1 << 3)
> > > +#define HDLCD_DEBUG_INT_MASK		(HDLCD_INTERRUPT_DMA_END |  \
> > > +					HDLCD_INTERRUPT_BUS_ERROR | \
> > > +					HDLCD_INTERRUPT_UNDERRUN)
> > > +
> > > +/* polarities */
> > > +#define HDLCD_POLARITY_VSYNC		(1 << 0)
> > > +#define HDLCD_POLARITY_HSYNC		(1 << 1)
> > > +#define HDLCD_POLARITY_DATAEN		(1 << 2)
> > > +#define HDLCD_POLARITY_DATA		(1 << 3)
> > > +#define HDLCD_POLARITY_PIXELCLK		(1 << 4)
> > > +
> > > +/* commands */
> > > +#define HDLCD_COMMAND_DISABLE		(0 << 0)
> > > +#define HDLCD_COMMAND_ENABLE		(1 << 0)
> > > +
> > > +/* pixel format */
> > > +#define HDLCD_PIXEL_FMT_LITTLE_ENDIAN	(0 << 31)
> > > +#define HDLCD_PIXEL_FMT_BIG_ENDIAN	(1 << 31)
> > > +#define HDLCD_BYTES_PER_PIXEL_MASK	(3 << 3)
> > > +
> > > +/* bus options */
> > > +#define HDLCD_BUS_BURST_MASK		0x01f
> > > +#define HDLCD_BUS_MAX_OUTSTAND		0xf00
> > > +#define HDLCD_BUS_BURST_NONE		(0 << 0)
> > > +#define HDLCD_BUS_BURST_1		(1 << 0)
> > > +#define HDLCD_BUS_BURST_2		(1 << 1)
> > > +#define HDLCD_BUS_BURST_4		(1 << 2)
> > > +#define HDLCD_BUS_BURST_8		(1 << 3)
> > > +#define HDLCD_BUS_BURST_16		(1 << 4)
> > > +
> > > +/* Max resolution supported is 4096x4096, 32bpp */
> > > +#define HDLCD_MAX_XRES			4096
> > > +#define HDLCD_MAX_YRES			4096
> > > +
> > > +#define NR_PALETTE			256
> > > +
> > > +#endif /* __HDLCD_REGS_H__ */
> > > -- 
> > > 2.6.2
> > > 
> > > _______________________________________________
> > > dri-devel mailing list
> > > dri-devel@lists.freedesktop.org
> > > http://lists.freedesktop.org/mailman/listinfo/dri-devel
> > 
> > -- 
> > Daniel Vetter
> > Software Engineer, Intel Corporation
> > http://blog.ffwll.ch
> 
> -- 
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/dri-devel

On Wed, Dec 02, 2015 at 04:24:19PM +0100, Daniel Vetter wrote:
> On Wed, Dec 02, 2015 at 12:23:00PM +0000, Liviu Dudau wrote:
> > The HDLCD controller is a display controller that supports resolutions
> > up to 4096x4096 pixels. It is present on various development boards
> > produced by ARM Ltd and emulated by the latest Fast Models from the
> > company.
> > 
> > Cc: David Airlie <airlied@linux.ie>
> > Cc: Robin Murphy <robin.murphy@arm.com>
> > 
> > Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>
> 
> A few small nitpicks below.
> 
> > ---
> >  drivers/gpu/drm/Kconfig          |   2 +
> >  drivers/gpu/drm/Makefile         |   1 +
> >  drivers/gpu/drm/arm/Kconfig      |  29 ++
> >  drivers/gpu/drm/arm/Makefile     |   2 +
> >  drivers/gpu/drm/arm/hdlcd_crtc.c | 334 +++++++++++++++++++++++
> >  drivers/gpu/drm/arm/hdlcd_drv.c  | 555 +++++++++++++++++++++++++++++++++++++++
> >  drivers/gpu/drm/arm/hdlcd_drv.h  |  42 +++
> >  drivers/gpu/drm/arm/hdlcd_regs.h |  87 ++++++
> >  8 files changed, 1052 insertions(+)
> >  create mode 100644 drivers/gpu/drm/arm/Kconfig
> >  create mode 100644 drivers/gpu/drm/arm/Makefile
> >  create mode 100644 drivers/gpu/drm/arm/hdlcd_crtc.c
> >  create mode 100644 drivers/gpu/drm/arm/hdlcd_drv.c
> >  create mode 100644 drivers/gpu/drm/arm/hdlcd_drv.h
> >  create mode 100644 drivers/gpu/drm/arm/hdlcd_regs.h
> > 
> > diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
> > index c4bf9a1..3fd9124 100644
> > --- a/drivers/gpu/drm/Kconfig
> > +++ b/drivers/gpu/drm/Kconfig
> > @@ -106,6 +106,8 @@ config DRM_TDFX
> >  	  Choose this option if you have a 3dfx Banshee or Voodoo3 (or later),
> >  	  graphics card.  If M is selected, the module will be called tdfx.
> >  
> > +source "drivers/gpu/drm/arm/Kconfig"
> > +
> >  config DRM_R128
> >  	tristate "ATI Rage 128"
> >  	depends on DRM && PCI
> > diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
> > index 1e9ff4c..6b42d75 100644
> > --- a/drivers/gpu/drm/Makefile
> > +++ b/drivers/gpu/drm/Makefile
> > @@ -35,6 +35,7 @@ CFLAGS_drm_trace_points.o := -I$(src)
> >  
> >  obj-$(CONFIG_DRM)	+= drm.o
> >  obj-$(CONFIG_DRM_MIPI_DSI) += drm_mipi_dsi.o
> > +obj-$(CONFIG_DRM_ARM)	+= arm/
> >  obj-$(CONFIG_DRM_TTM)	+= ttm/
> >  obj-$(CONFIG_DRM_TDFX)	+= tdfx/
> >  obj-$(CONFIG_DRM_R128)	+= r128/
> > diff --git a/drivers/gpu/drm/arm/Kconfig b/drivers/gpu/drm/arm/Kconfig
> > new file mode 100644
> > index 0000000..5e8c8a8
> > --- /dev/null
> > +++ b/drivers/gpu/drm/arm/Kconfig
> > @@ -0,0 +1,29 @@
> > +config DRM_ARM
> > +	bool "ARM Ltd. drivers"
> > +	depends on DRM && OF && (ARM || ARM64)
> > +	select DRM_KMS_HELPER
> > +	help
> > +	  Choose this option to select drivers for ARM's devices
> > +
> > +config DRM_HDLCD
> > +	tristate "ARM HDLCD"
> > +	depends on DRM_ARM
> > +	depends on COMMON_CLK
> > +	select COMMON_CLK_SCPI
> > +	select DMA_CMA
> > +	select DRM_KMS_CMA_HELPER
> > +	select DRM_GEM_CMA_HELPER
> > +	help
> > +	  Choose this option if you have an ARM High Definition Colour LCD
> > +	  controller.
> > +
> > +	  If M is selected the module will be called hdlcd.
> > +
> > +config DRM_HDLCD_SHOW_UNDERRUN
> > +	bool "Show underrun conditions"
> > +	depends on DRM_HDLCD
> > +	default n
> > +	help
> > +	  Enable this option to show in red colour the pixels that the
> > +	  HDLCD device did not fetch from framebuffer due to underrun
> > +	  conditions.
> > diff --git a/drivers/gpu/drm/arm/Makefile b/drivers/gpu/drm/arm/Makefile
> > new file mode 100644
> > index 0000000..89dcb7b
> > --- /dev/null
> > +++ b/drivers/gpu/drm/arm/Makefile
> > @@ -0,0 +1,2 @@
> > +hdlcd-y := hdlcd_drv.o hdlcd_crtc.o
> > +obj-$(CONFIG_DRM_HDLCD)	+= hdlcd.o
> > diff --git a/drivers/gpu/drm/arm/hdlcd_crtc.c b/drivers/gpu/drm/arm/hdlcd_crtc.c
> > new file mode 100644
> > index 0000000..350c1fe
> > --- /dev/null
> > +++ b/drivers/gpu/drm/arm/hdlcd_crtc.c
> > @@ -0,0 +1,334 @@
> > +/*
> > + * Copyright (C) 2013-2015 ARM Limited
> > + * Author: Liviu Dudau <Liviu.Dudau@arm.com>
> > + *
> > + * This file is subject to the terms and conditions of the GNU General Public
> > + * License.  See the file COPYING in the main directory of this archive
> > + * for more details.
> > + *
> > + *  Implementation of a CRTC class for the HDLCD driver.
> > + */
> > +
> > +#include <drm/drmP.h>
> > +#include <drm/drm_atomic_helper.h>
> > +#include <drm/drm_crtc.h>
> > +#include <drm/drm_crtc_helper.h>
> > +#include <drm/drm_fb_helper.h>
> > +#include <drm/drm_fb_cma_helper.h>
> > +#include <drm/drm_gem_cma_helper.h>
> > +#include <drm/drm_of.h>
> > +#include <drm/drm_plane_helper.h>
> > +#include <linux/clk.h>
> > +#include <linux/of_graph.h>
> > +#include <linux/platform_data/simplefb.h>
> > +#include <video/videomode.h>
> > +
> > +#include "hdlcd_drv.h"
> > +#include "hdlcd_regs.h"
> > +
> > +/*
> > + * The HDLCD controller is a dumb RGB streamer that gets connected to
> > + * a single HDMI transmitter or in the case of the ARM Models it gets
> > + * emulated by the software that does the actual rendering.
> > + *
> > + */
> > +
> > +static const struct drm_crtc_funcs hdlcd_crtc_funcs = {
> > +	.destroy = drm_crtc_cleanup,
> > +	.set_config = drm_atomic_helper_set_config,
> > +	.page_flip = drm_atomic_helper_page_flip,
> > +	.reset = drm_atomic_helper_crtc_reset,
> > +	.atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
> > +	.atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
> > +};
> > +
> > +static struct simplefb_format supported_formats[] = SIMPLEFB_FORMATS;
> > +
> > +/*
> > + * Setup the HDLCD registers for decoding the pixels out of the framebuffer
> > + */
> > +static int hdlcd_set_pxl_fmt(struct drm_crtc *crtc)
> > +{
> > +	unsigned int btpp, default_color = 0x00000000;
> > +	struct hdlcd_drm_private *hdlcd = crtc_to_hdlcd_priv(crtc);
> > +	uint32_t pixel_format;
> > +	struct simplefb_format *format = NULL;
> > +	int i;
> > +
> > +#ifdef CONFIG_DRM_HDLCD_SHOW_UNDERRUN
> > +	default_color = 0x00ff0000;	/* show underruns in red */
> > +#endif
> > +
> > +	if (!crtc->primary->state->fb) {
> > +		DRM_ERROR("No fb associated with state %p\n",
> > +			  crtc->primary->state);
> > +		return -EINVAL;
> 
> The higher-level ->mode_set_nofb can't fail and you're violating this
> here. Correct fix in atomic is to check in your crtc->atomic_check that
> there's always a primary fb set. Since that's a small dance (you need to
> grab the primary plane state first) might be good to extract it into a
> small helper, but not really needed.
> 
> Here you should WARN_ON if this ever happens and just return (without
> trying to track an error code), since it's too late already.

Just realised that this check serves no purpose. I added it for debugging
purpose while tracking the TDA19988 atomic support and forgot to remove it.
I will do so in v4.

Best regards,
Liviu

> 
> > +	}
> > +
> > +	pixel_format = crtc->primary->state->fb->pixel_format;
> > +
> > +	for (i = 0; i < ARRAY_SIZE(supported_formats); i++) {
> > +		if (supported_formats[i].fourcc == pixel_format)
> > +			format = &supported_formats[i];
> > +	}
> > +
> > +	if (!format) {
> > +		DRM_ERROR("Format not supported: 0x%x\n", pixel_format);
> > +		return -EINVAL;
> > +	}
> 
> Same here. Although this should be impossible, with atomic the
> core/helpers pre-check the pixel format against the format table you
> register on the (primary) plane already. So just WARN_ON + bailing out.
> 
> > +
> > +	/* HDLCD uses 'bytes per pixel', zero means 1 byte */
> > +	btpp = (format->bits_per_pixel + 7) / 8;
> > +	hdlcd_write(hdlcd, HDLCD_REG_PIXEL_FORMAT, (btpp - 1) << 3);
> > +
> > +	/*
> > +	 * The format of the HDLCD_REG_<color>_SELECT register is:
> > +	 *   - bits[23:16] - default value for that color component
> > +	 *   - bits[11:8]  - number of bits to extract for each color component
> > +	 *   - bits[4:0]   - index of the lowest bit to extract
> > +	 *
> > +	 * The default color value is used when bits[11:8] are zero, when the
> > +	 * pixel is outside the visible frame area or when there is a
> > +	 * buffer underrun.
> > +	 */
> > +	hdlcd_write(hdlcd, HDLCD_REG_RED_SELECT, default_color |
> > +		format->red.offset | (format->red.length & 0xf) << 8);
> > +	hdlcd_write(hdlcd, HDLCD_REG_GREEN_SELECT, default_color |
> > +		format->green.offset | (format->green.length & 0xf) << 8);
> > +	hdlcd_write(hdlcd, HDLCD_REG_BLUE_SELECT, default_color |
> > +		format->blue.offset | (format->blue.length & 0xf) << 8);
> > +
> > +	return 0;
> > +}
> > +
> > +static void hdlcd_crtc_mode_set_nofb(struct drm_crtc *crtc)
> > +{
> > +	struct hdlcd_drm_private *hdlcd = crtc_to_hdlcd_priv(crtc);
> > +	struct drm_display_mode *m = &crtc->state->adjusted_mode;
> > +	struct videomode vm;
> > +	unsigned int polarities, line_length, err;
> > +
> > +	vm.vfront_porch = m->crtc_vsync_start - m->crtc_vdisplay;
> > +	vm.vback_porch = m->crtc_vtotal - m->crtc_vsync_end;
> > +	vm.vsync_len = m->crtc_vsync_end - m->crtc_vsync_start;
> > +	vm.hfront_porch = m->crtc_hsync_start - m->crtc_hdisplay;
> > +	vm.hback_porch = m->crtc_htotal - m->crtc_hsync_end;
> > +	vm.hsync_len = m->crtc_hsync_end - m->crtc_hsync_start;
> > +
> > +	polarities = HDLCD_POLARITY_DATAEN | HDLCD_POLARITY_DATA;
> > +
> > +	if (m->flags & DRM_MODE_FLAG_PHSYNC)
> > +		polarities |= HDLCD_POLARITY_HSYNC;
> > +	if (m->flags & DRM_MODE_FLAG_PVSYNC)
> > +		polarities |= HDLCD_POLARITY_VSYNC;
> > +
> > +	line_length = crtc->primary->state->fb->pitches[0];
> > +
> > +	/* Allow max number of outstanding requests and largest burst size */
> > +	hdlcd_write(hdlcd, HDLCD_REG_BUS_OPTIONS,
> > +		    HDLCD_BUS_MAX_OUTSTAND | HDLCD_BUS_BURST_16);
> > +
> > +	hdlcd_write(hdlcd, HDLCD_REG_FB_LINE_LENGTH, line_length);
> > +	hdlcd_write(hdlcd, HDLCD_REG_FB_LINE_PITCH, line_length);
> > +	hdlcd_write(hdlcd, HDLCD_REG_FB_LINE_COUNT, m->crtc_vdisplay - 1);
> > +	hdlcd_write(hdlcd, HDLCD_REG_V_DATA, m->crtc_vdisplay - 1);
> > +	hdlcd_write(hdlcd, HDLCD_REG_V_BACK_PORCH, vm.vback_porch - 1);
> > +	hdlcd_write(hdlcd, HDLCD_REG_V_FRONT_PORCH, vm.vfront_porch - 1);
> > +	hdlcd_write(hdlcd, HDLCD_REG_V_SYNC, vm.vsync_len - 1);
> > +	hdlcd_write(hdlcd, HDLCD_REG_H_BACK_PORCH, vm.hback_porch - 1);
> > +	hdlcd_write(hdlcd, HDLCD_REG_H_FRONT_PORCH, vm.hfront_porch - 1);
> > +	hdlcd_write(hdlcd, HDLCD_REG_H_SYNC, vm.hsync_len - 1);
> > +	hdlcd_write(hdlcd, HDLCD_REG_H_DATA, m->crtc_hdisplay - 1);
> > +	hdlcd_write(hdlcd, HDLCD_REG_POLARITIES, polarities);
> > +
> > +	err = hdlcd_set_pxl_fmt(crtc);
> > +	if (err)
> > +		return;
> > +
> > +	clk_set_rate(hdlcd->clk, m->crtc_clock * 1000);
> > +}
> > +
> > +static void hdlcd_crtc_enable(struct drm_crtc *crtc)
> > +{
> > +	struct hdlcd_drm_private *hdlcd = crtc_to_hdlcd_priv(crtc);
> > +
> > +	clk_prepare_enable(hdlcd->clk);
> > +	hdlcd_write(hdlcd, HDLCD_REG_COMMAND, 1);
> > +	drm_crtc_vblank_on(crtc);
> > +}
> > +
> > +static void hdlcd_crtc_disable(struct drm_crtc *crtc)
> > +{
> > +	struct hdlcd_drm_private *hdlcd = crtc_to_hdlcd_priv(crtc);
> > +
> > +	if (!crtc->primary->fb)
> > +		return;
> > +
> > +	clk_disable_unprepare(hdlcd->clk);
> > +	hdlcd_write(hdlcd, HDLCD_REG_COMMAND, 0);
> > +	drm_crtc_vblank_off(crtc);
> > +}
> > +
> > +static int hdlcd_crtc_atomic_check(struct drm_crtc *crtc,
> > +				   struct drm_crtc_state *state)
> > +{
> > +	struct hdlcd_drm_private *hdlcd = crtc_to_hdlcd_priv(crtc);
> > +	struct drm_display_mode *mode = &state->adjusted_mode;
> > +	long rate, clk_rate = mode->clock * 1000;
> > +
> > +	rate = clk_round_rate(hdlcd->clk, clk_rate);
> > +	if (rate != clk_rate) {
> > +		/* clock required by mode not supported by hardware */
> > +		return -EINVAL;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static void hdlcd_crtc_atomic_begin(struct drm_crtc *crtc,
> > +				    struct drm_crtc_state *state)
> > +{
> > +	struct hdlcd_drm_private *hdlcd = crtc_to_hdlcd_priv(crtc);
> > +	unsigned long flags;
> > +
> > +	if (crtc->state->event) {
> > +		crtc->state->event->pipe = drm_crtc_index(crtc);
> > +
> > +		WARN_ON(drm_crtc_vblank_get(crtc) != 0);
> > +
> > +		spin_lock_irqsave(&crtc->dev->event_lock, flags);
> > +		hdlcd->event = crtc->state->event;
> > +		spin_unlock_irqrestore(&crtc->dev->event_lock, flags);
> > +		crtc->state->event = NULL;
> > +	}
> > +}
> > +
> > +static void hdlcd_crtc_atomic_flush(struct drm_crtc *crtc,
> > +				    struct drm_crtc_state *state)
> > +{
> > +}
> > +
> > +static bool hdlcd_crtc_mode_fixup(struct drm_crtc *crtc,
> > +			const struct drm_display_mode *mode,
> > +			struct drm_display_mode *adjusted_mode)
> > +{
> > +	return true;
> > +}
> > +
> > +static const struct drm_crtc_helper_funcs hdlcd_crtc_helper_funcs = {
> > +	.mode_fixup	= hdlcd_crtc_mode_fixup,
> > +	.mode_set	= drm_helper_crtc_mode_set,
> > +	.mode_set_base	= drm_helper_crtc_mode_set_base,
> > +	.mode_set_nofb	= hdlcd_crtc_mode_set_nofb,
> > +	.enable		= hdlcd_crtc_enable,
> > +	.disable	= hdlcd_crtc_disable,
> > +	.prepare	= hdlcd_crtc_disable,
> > +	.commit		= hdlcd_crtc_enable,
> > +	.atomic_check	= hdlcd_crtc_atomic_check,
> > +	.atomic_begin	= hdlcd_crtc_atomic_begin,
> > +	.atomic_flush	= hdlcd_crtc_atomic_flush,
> > +};
> > +
> > +static int hdlcd_plane_atomic_check(struct drm_plane *plane,
> > +				    struct drm_plane_state *state)
> > +{
> > +	return 0;
> > +}
> > +
> > +static void hdlcd_plane_atomic_update(struct drm_plane *plane,
> > +				      struct drm_plane_state *state)
> > +{
> > +	struct hdlcd_drm_private *hdlcd;
> > +	struct drm_gem_cma_object *gem;
> > +	dma_addr_t scanout_start;
> > +
> > +	if (!plane->state->crtc || !plane->state->fb)
> > +		return;
> > +
> > +	hdlcd = crtc_to_hdlcd_priv(plane->state->crtc);
> > +	gem = drm_fb_cma_get_gem_obj(plane->state->fb, 0);
> > +	scanout_start = gem->paddr;
> > +	hdlcd_write(hdlcd, HDLCD_REG_FB_BASE, scanout_start);
> > +}
> > +
> > +static const struct drm_plane_helper_funcs hdlcd_plane_helper_funcs = {
> > +	.prepare_fb = NULL,
> > +	.cleanup_fb = NULL,
> > +	.atomic_check = hdlcd_plane_atomic_check,
> > +	.atomic_update = hdlcd_plane_atomic_update,
> > +};
> > +
> > +static void hdlcd_plane_destroy(struct drm_plane *plane)
> > +{
> > +	drm_plane_helper_disable(plane);
> > +	drm_plane_cleanup(plane);
> > +}
> > +
> > +static const struct drm_plane_funcs hdlcd_plane_funcs = {
> > +	.update_plane		= drm_atomic_helper_update_plane,
> > +	.disable_plane		= drm_atomic_helper_disable_plane,
> > +	.destroy		= hdlcd_plane_destroy,
> > +	.reset			= drm_atomic_helper_plane_reset,
> > +	.atomic_duplicate_state = drm_atomic_helper_plane_duplicate_state,
> > +	.atomic_destroy_state	= drm_atomic_helper_plane_destroy_state,
> > +};
> > +
> > +static struct drm_plane *hdlcd_plane_init(struct drm_device *drm)
> > +{
> > +	struct hdlcd_drm_private *hdlcd = drm->dev_private;
> > +	struct drm_plane *plane = NULL;
> > +	u32 formats[ARRAY_SIZE(supported_formats)], i;
> > +	int ret;
> > +
> > +	plane = devm_kzalloc(drm->dev, sizeof(*plane), GFP_KERNEL);
> > +	if (!plane)
> > +		return ERR_PTR(-ENOMEM);
> > +
> > +	for (i = 0; i < ARRAY_SIZE(supported_formats); i++)
> > +		formats[i] = supported_formats[i].fourcc;
> > +
> > +	ret = drm_universal_plane_init(drm, plane, 0xff, &hdlcd_plane_funcs,
> > +				       formats, ARRAY_SIZE(formats),
> > +				       DRM_PLANE_TYPE_PRIMARY);
> > +	if (ret) {
> > +		devm_kfree(drm->dev, plane);
> > +		return ERR_PTR(ret);
> > +	}
> > +
> > +	drm_plane_helper_add(plane, &hdlcd_plane_helper_funcs);
> > +	hdlcd->plane = plane;
> > +
> > +	return plane;
> > +}
> > +
> > +void hdlcd_crtc_suspend(struct drm_crtc *crtc)
> > +{
> > +	hdlcd_crtc_disable(crtc);
> > +}
> > +
> > +void hdlcd_crtc_resume(struct drm_crtc *crtc)
> > +{
> > +	hdlcd_crtc_enable(crtc);
> > +}
> > +
> > +int hdlcd_setup_crtc(struct drm_device *drm)
> > +{
> > +	struct hdlcd_drm_private *hdlcd = drm->dev_private;
> > +	struct drm_plane *primary;
> > +	int ret;
> > +
> > +	primary = hdlcd_plane_init(drm);
> > +	if (IS_ERR(primary))
> > +		return PTR_ERR(primary);
> > +
> > +	ret = drm_crtc_init_with_planes(drm, &hdlcd->crtc, primary, NULL,
> > +					&hdlcd_crtc_funcs);
> > +	if (ret) {
> > +		hdlcd_plane_destroy(primary);
> > +		devm_kfree(drm->dev, primary);
> > +		return ret;
> > +	}
> > +
> > +	drm_crtc_helper_add(&hdlcd->crtc, &hdlcd_crtc_helper_funcs);
> > +	return 0;
> > +}
> > diff --git a/drivers/gpu/drm/arm/hdlcd_drv.c b/drivers/gpu/drm/arm/hdlcd_drv.c
> > new file mode 100644
> > index 0000000..45440b1
> > --- /dev/null
> > +++ b/drivers/gpu/drm/arm/hdlcd_drv.c
> > @@ -0,0 +1,555 @@
> > +/*
> > + * Copyright (C) 2013-2015 ARM Limited
> > + * Author: Liviu Dudau <Liviu.Dudau@arm.com>
> > + *
> > + * This file is subject to the terms and conditions of the GNU General Public
> > + * License.  See the file COPYING in the main directory of this archive
> > + * for more details.
> > + *
> > + *  ARM HDLCD Driver
> > + */
> > +
> > +#include <linux/module.h>
> > +#include <linux/spinlock.h>
> > +#include <linux/clk.h>
> > +#include <linux/component.h>
> > +#include <linux/of_graph.h>
> > +#include <linux/of_reserved_mem.h>
> > +#include <linux/pm_runtime.h>
> > +
> > +#include <drm/drmP.h>
> > +#include <drm/drm_atomic_helper.h>
> > +#include <drm/drm_crtc.h>
> > +#include <drm/drm_crtc_helper.h>
> > +#include <drm/drm_fb_helper.h>
> > +#include <drm/drm_fb_cma_helper.h>
> > +#include <drm/drm_gem_cma_helper.h>
> > +#include <drm/drm_of.h>
> > +
> > +#include "hdlcd_drv.h"
> > +#include "hdlcd_regs.h"
> > +
> > +static int compare_dev(struct device *dev, void *data)
> > +{
> > +	return dev->of_node == data;
> > +}
> > +
> > +static int hdlcd_load(struct drm_device *drm, unsigned long flags)
> > +{
> > +	struct hdlcd_drm_private *hdlcd = drm->dev_private;
> > +	struct platform_device *pdev = to_platform_device(drm->dev);
> > +	struct resource *res;
> > +	u32 version;
> > +	int ret;
> > +
> > +	hdlcd->clk = devm_clk_get(drm->dev, "pxlclk");
> > +	if (IS_ERR(hdlcd->clk))
> > +		return PTR_ERR(hdlcd->clk);
> > +
> > +#ifdef CONFIG_DEBUG_FS
> > +	atomic_set(&hdlcd->buffer_underrun_count, 0);
> > +	atomic_set(&hdlcd->bus_error_count, 0);
> > +	atomic_set(&hdlcd->vsync_count, 0);
> > +	atomic_set(&hdlcd->dma_end_count, 0);
> > +#endif
> > +
> > +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > +	hdlcd->mmio = devm_ioremap_resource(drm->dev, res);
> > +	if (IS_ERR(hdlcd->mmio)) {
> > +		DRM_ERROR("failed to map control registers area\n");
> > +		ret = PTR_ERR(hdlcd->mmio);
> > +		hdlcd->mmio = NULL;
> > +		goto fail;
> > +	}
> > +
> > +	version = hdlcd_read(hdlcd, HDLCD_REG_VERSION);
> > +	if ((version & HDLCD_PRODUCT_MASK) != HDLCD_PRODUCT_ID) {
> > +		DRM_ERROR("unknown product id: 0x%x\n", version);
> > +		ret = -EINVAL;
> > +		goto fail;
> > +	}
> > +	DRM_INFO("found ARM HDLCD version r%dp%d\n",
> > +		(version & HDLCD_VERSION_MAJOR_MASK) >> 8,
> > +		version & HDLCD_VERSION_MINOR_MASK);
> > +
> > +	/* Get the optional framebuffer memory resource */
> > +	ret = of_reserved_mem_device_init(drm->dev);
> > +	if (ret && ret != -ENODEV)
> > +		goto fail;
> > +
> > +	ret = dma_set_mask_and_coherent(drm->dev, DMA_BIT_MASK(32));
> > +	if (ret)
> > +		goto setup_fail;
> > +
> > +	ret = hdlcd_setup_crtc(drm);
> > +	if (ret < 0) {
> > +		DRM_ERROR("failed to create crtc\n");
> > +		goto setup_fail;
> > +	}
> > +
> > +	pm_runtime_enable(drm->dev);
> > +
> > +	pm_runtime_get_sync(drm->dev);
> > +	ret = drm_irq_install(drm, platform_get_irq(pdev, 0));
> > +	pm_runtime_put_sync(drm->dev);
> > +	if (ret < 0) {
> > +		DRM_ERROR("failed to install IRQ handler\n");
> > +		goto irq_fail;
> > +	}
> > +
> > +	return 0;
> > +
> > +irq_fail:
> > +	drm_crtc_cleanup(&hdlcd->crtc);
> > +setup_fail:
> > +	of_reserved_mem_device_release(drm->dev);
> > +fail:
> > +	devm_clk_put(drm->dev, hdlcd->clk);
> > +
> > +	return ret;
> > +}
> > +
> > +static void hdlcd_fb_output_poll_changed(struct drm_device *drm)
> > +{
> > +	struct hdlcd_drm_private *hdlcd = drm->dev_private;
> > +
> > +	if (hdlcd->fbdev) {
> > +		drm_fbdev_cma_hotplug_event(hdlcd->fbdev);
> > +	}
> > +}
> > +
> > +static const struct drm_mode_config_funcs hdlcd_mode_config_funcs = {
> > +	.fb_create = drm_fb_cma_create,
> > +	.output_poll_changed = hdlcd_fb_output_poll_changed,
> > +	.atomic_check = drm_atomic_helper_check,
> > +	.atomic_commit = drm_atomic_helper_commit,
> > +};
> > +
> > +static void hdlcd_setup_mode_config(struct drm_device *drm)
> > +{
> > +	drm_mode_config_init(drm);
> > +	drm->mode_config.min_width = 0;
> > +	drm->mode_config.min_height = 0;
> > +	drm->mode_config.max_width = HDLCD_MAX_XRES;
> > +	drm->mode_config.max_height = HDLCD_MAX_YRES;
> > +	drm->mode_config.funcs = &hdlcd_mode_config_funcs;
> > +}
> > +
> > +static void hdlcd_preclose(struct drm_device *drm, struct drm_file *file)
> > +{
> > +}
> > +
> > +static void hdlcd_lastclose(struct drm_device *drm)
> > +{
> > +	struct hdlcd_drm_private *hdlcd = drm->dev_private;
> > +
> > +	drm_fbdev_cma_restore_mode(hdlcd->fbdev);
> > +}
> > +
> > +static irqreturn_t hdlcd_irq(int irq, void *arg)
> > +{
> > +	struct drm_device *drm = arg;
> > +	struct hdlcd_drm_private *hdlcd = drm->dev_private;
> > +	unsigned long irq_status;
> > +
> > +	irq_status = hdlcd_read(hdlcd, HDLCD_REG_INT_STATUS);
> > +
> > +#ifdef CONFIG_DEBUG_FS
> > +	if (irq_status & HDLCD_INTERRUPT_UNDERRUN) {
> > +		atomic_inc(&hdlcd->buffer_underrun_count);
> > +	}
> > +	if (irq_status & HDLCD_INTERRUPT_DMA_END) {
> > +		atomic_inc(&hdlcd->dma_end_count);
> > +	}
> > +	if (irq_status & HDLCD_INTERRUPT_BUS_ERROR) {
> > +		atomic_inc(&hdlcd->bus_error_count);
> > +	}
> > +	if (irq_status & HDLCD_INTERRUPT_VSYNC) {
> > +		atomic_inc(&hdlcd->vsync_count);
> > +	}
> > +#endif
> > +	if (irq_status & HDLCD_INTERRUPT_VSYNC) {
> > +		unsigned long flags;
> > +
> > +		drm_handle_vblank(drm, 0);
> 
> We have drm_crtc_ versions for this one ...
> > +
> > +		spin_lock_irqsave(&drm->event_lock, flags);
> > +		if (hdlcd->event) {
> > +			drm_send_vblank_event(drm, hdlcd->event->pipe, hdlcd->event);
> 
> and this one now too. New drivers shouldn't need to deal with the opaque
> int pipe stuff any more on the caller sides, and real soon (hopefully)
> we'll have hooks for the vblank stuff that take struct drm_crtc * too.
> 
> I've quickly scrolled through the driver otherwise and didn't notice
> anything else that should be updated to latest practices. Looks really
> good.
> -Daniel
> 
> > +			drm_crtc_vblank_put(&hdlcd->crtc);
> > +			hdlcd->event = NULL;
> > +		}
> > +		spin_unlock_irqrestore(&drm->event_lock, flags);
> > +	}
> > +
> > +	/* acknowledge interrupt(s) */
> > +	hdlcd_write(hdlcd, HDLCD_REG_INT_CLEAR, irq_status);
> > +
> > +	return IRQ_HANDLED;
> > +}
> > +
> > +static void hdlcd_irq_preinstall(struct drm_device *drm)
> > +{
> > +	struct hdlcd_drm_private *hdlcd = drm->dev_private;
> > +	/* Ensure interrupts are disabled */
> > +	hdlcd_write(hdlcd, HDLCD_REG_INT_MASK, 0);
> > +	hdlcd_write(hdlcd, HDLCD_REG_INT_CLEAR, ~0);
> > +}
> > +
> > +static int hdlcd_irq_postinstall(struct drm_device *drm)
> > +{
> > +#ifdef CONFIG_DEBUG_FS
> > +	struct hdlcd_drm_private *hdlcd = drm->dev_private;
> > +	unsigned long irq_mask = hdlcd_read(hdlcd, HDLCD_REG_INT_MASK);
> > +
> > +	/* enable debug interrupts */
> > +	irq_mask |= HDLCD_DEBUG_INT_MASK;
> > +
> > +	hdlcd_write(hdlcd, HDLCD_REG_INT_MASK, irq_mask);
> > +#endif
> > +	return 0;
> > +}
> > +
> > +static void hdlcd_irq_uninstall(struct drm_device *drm)
> > +{
> > +	struct hdlcd_drm_private *hdlcd = drm->dev_private;
> > +	/* disable all the interrupts that we might have enabled */
> > +	unsigned long irq_mask = hdlcd_read(hdlcd, HDLCD_REG_INT_MASK);
> > +
> > +#ifdef CONFIG_DEBUG_FS
> > +	/* disable debug interrupts */
> > +	irq_mask &= ~HDLCD_DEBUG_INT_MASK;
> > +#endif
> > +
> > +	/* disable vsync interrupts */
> > +	irq_mask &= ~HDLCD_INTERRUPT_VSYNC;
> > +
> > +	hdlcd_write(hdlcd, HDLCD_REG_INT_MASK, irq_mask);
> > +}
> > +
> > +static int hdlcd_enable_vblank(struct drm_device *drm, unsigned int crtc)
> > +{
> > +	struct hdlcd_drm_private *hdlcd = drm->dev_private;
> > +	unsigned int mask = hdlcd_read(hdlcd, HDLCD_REG_INT_MASK);
> > +
> > +	hdlcd_write(hdlcd, HDLCD_REG_INT_MASK, mask | HDLCD_INTERRUPT_VSYNC);
> > +
> > +	return 0;
> > +}
> > +
> > +static void hdlcd_disable_vblank(struct drm_device *drm, unsigned int crtc)
> > +{
> > +	struct hdlcd_drm_private *hdlcd = drm->dev_private;
> > +	unsigned int mask = hdlcd_read(hdlcd, HDLCD_REG_INT_MASK);
> > +
> > +	hdlcd_write(hdlcd, HDLCD_REG_INT_MASK, mask & ~HDLCD_INTERRUPT_VSYNC);
> > +}
> > +
> > +#ifdef CONFIG_DEBUG_FS
> > +static int hdlcd_show_underrun_count(struct seq_file *m, void *arg)
> > +{
> > +	struct drm_info_node *node = (struct drm_info_node *)m->private;
> > +	struct drm_device *drm = node->minor->dev;
> > +	struct hdlcd_drm_private *hdlcd = drm->dev_private;
> > +
> > +	seq_printf(m, "underrun : %d\n", atomic_read(&hdlcd->buffer_underrun_count));
> > +	seq_printf(m, "dma_end  : %d\n", atomic_read(&hdlcd->dma_end_count));
> > +	seq_printf(m, "bus_error: %d\n", atomic_read(&hdlcd->bus_error_count));
> > +	seq_printf(m, "vsync    : %d\n", atomic_read(&hdlcd->vsync_count));
> > +	return 0;
> > +}
> > +
> > +static int hdlcd_show_pxlclock(struct seq_file *m, void *arg)
> > +{
> > +	struct drm_info_node *node = (struct drm_info_node *)m->private;
> > +	struct drm_device *drm = node->minor->dev;
> > +	struct hdlcd_drm_private *hdlcd = drm->dev_private;
> > +	unsigned long clkrate = clk_get_rate(hdlcd->clk);
> > +	unsigned long mode_clock = hdlcd->crtc.mode.crtc_clock * 1000;
> > +
> > +	seq_printf(m, "hw  : %lu\n", clkrate);
> > +	seq_printf(m, "mode: %lu\n", mode_clock);
> > +	return 0;
> > +}
> > +
> > +static struct drm_info_list hdlcd_debugfs_list[] = {
> > +	{ "interrupt_count", hdlcd_show_underrun_count, 0 },
> > +	{ "clocks", hdlcd_show_pxlclock, 0 },
> > +};
> > +
> > +static int hdlcd_debugfs_init(struct drm_minor *minor)
> > +{
> > +	return drm_debugfs_create_files(hdlcd_debugfs_list,
> > +		ARRAY_SIZE(hdlcd_debugfs_list),	minor->debugfs_root, minor);
> > +}
> > +
> > +static void hdlcd_debugfs_cleanup(struct drm_minor *minor)
> > +{
> > +	drm_debugfs_remove_files(hdlcd_debugfs_list,
> > +		ARRAY_SIZE(hdlcd_debugfs_list), minor);
> > +}
> > +#endif
> > +
> > +static const struct file_operations fops = {
> > +	.owner		= THIS_MODULE,
> > +	.open		= drm_open,
> > +	.release	= drm_release,
> > +	.unlocked_ioctl	= drm_ioctl,
> > +#ifdef CONFIG_COMPAT
> > +	.compat_ioctl	= drm_compat_ioctl,
> > +#endif
> > +	.poll		= drm_poll,
> > +	.read		= drm_read,
> > +	.llseek		= noop_llseek,
> > +	.mmap		= drm_gem_cma_mmap,
> > +};
> > +
> > +static struct drm_driver hdlcd_driver = {
> > +	.driver_features = DRIVER_HAVE_IRQ | DRIVER_GEM |
> > +			   DRIVER_MODESET | DRIVER_PRIME |
> > +			   DRIVER_ATOMIC,
> > +	.preclose = hdlcd_preclose,
> > +	.lastclose = hdlcd_lastclose,
> > +	.irq_handler = hdlcd_irq,
> > +	.irq_preinstall = hdlcd_irq_preinstall,
> > +	.irq_postinstall = hdlcd_irq_postinstall,
> > +	.irq_uninstall = hdlcd_irq_uninstall,
> > +	.get_vblank_counter = drm_vblank_no_hw_counter,
> > +	.enable_vblank = hdlcd_enable_vblank,
> > +	.disable_vblank = hdlcd_disable_vblank,
> > +	.gem_free_object = drm_gem_cma_free_object,
> > +	.gem_vm_ops = &drm_gem_cma_vm_ops,
> > +	.dumb_create = drm_gem_cma_dumb_create,
> > +	.dumb_map_offset = drm_gem_cma_dumb_map_offset,
> > +	.dumb_destroy = drm_gem_dumb_destroy,
> > +	.prime_handle_to_fd = drm_gem_prime_handle_to_fd,
> > +	.prime_fd_to_handle = drm_gem_prime_fd_to_handle,
> > +	.gem_prime_export = drm_gem_prime_export,
> > +	.gem_prime_import = drm_gem_prime_import,
> > +	.gem_prime_get_sg_table = drm_gem_cma_prime_get_sg_table,
> > +	.gem_prime_import_sg_table = drm_gem_cma_prime_import_sg_table,
> > +	.gem_prime_vmap = drm_gem_cma_prime_vmap,
> > +	.gem_prime_vunmap = drm_gem_cma_prime_vunmap,
> > +	.gem_prime_mmap = drm_gem_cma_prime_mmap,
> > +#ifdef CONFIG_DEBUG_FS
> > +	.debugfs_init = hdlcd_debugfs_init,
> > +	.debugfs_cleanup = hdlcd_debugfs_cleanup,
> > +#endif
> > +	.fops = &fops,
> > +	.name = "hdlcd",
> > +	.desc = "ARM HDLCD Controller DRM",
> > +	.date = "20151021",
> > +	.major = 1,
> > +	.minor = 0,
> > +};
> > +
> > +static int hdlcd_add_components(struct device *dev, struct master *master)
> > +{
> > +	struct device_node *port, *ep = NULL;
> > +	int ret = -ENXIO;
> > +
> > +	if (!dev->of_node)
> > +		return -ENODEV;
> > +
> > +	do {
> > +		ep = of_graph_get_next_endpoint(dev->of_node, ep);
> > +		if (!ep)
> > +			break;
> > +
> > +		if (!of_device_is_available(ep)) {
> > +			of_node_put(ep);
> > +			continue;
> > +		}
> > +
> > +		port = of_graph_get_remote_port_parent(ep);
> > +		of_node_put(ep);
> > +		if (!port || !of_device_is_available(port)) {
> > +			of_node_put(port);
> > +			continue;
> > +		}
> > +
> > +		ret = component_master_add_child(master, compare_dev, port);
> > +		of_node_put(port);
> > +	} while (1);
> > +
> > +	return ret;
> > +}
> > +
> > +static int hdlcd_drm_bind(struct device *dev)
> > +{
> > +	struct drm_device *drm;
> > +	struct hdlcd_drm_private *hdlcd;
> > +	int ret;
> > +
> > +	hdlcd = devm_kzalloc(dev, sizeof(*hdlcd), GFP_KERNEL);
> > +	if (!hdlcd)
> > +		return -ENOMEM;
> > +
> > +	drm = drm_dev_alloc(&hdlcd_driver, dev);
> > +	if (!drm)
> > +		return -ENOMEM;
> > +
> > +	drm->dev_private = hdlcd;
> > +
> > +	ret = drm_dev_set_unique(drm, "%s", dev_name(dev));
> > +	if (ret)
> > +		goto err_free;
> > +
> > +	hdlcd_setup_mode_config(drm);
> > +
> > +	ret = hdlcd_load(drm, 0);
> > +	if (ret)
> > +		goto err_free;
> > +
> > +	ret = drm_dev_register(drm, 0);
> > +	if (ret)
> > +		goto err_unload;
> > +
> > +	dev_set_drvdata(dev, drm);
> > +
> > +	ret = component_bind_all(dev, drm);
> > +	if (ret) {
> > +		DRM_ERROR("Failed to bind all components\n");
> > +		goto err_unregister;
> > +	}
> > +
> > +	ret = drm_vblank_init(drm, drm->mode_config.num_crtc);
> > +	if (ret < 0) {
> > +		DRM_ERROR("failed to initialise vblank\n");
> > +		goto err_vblank;
> > +	}
> > +	drm->vblank_disable_allowed = true;
> > +
> > +	drm_mode_config_reset(drm);
> > +	drm_kms_helper_poll_init(drm);
> > +
> > +	hdlcd->fbdev = drm_fbdev_cma_init(drm, 32, drm->mode_config.num_crtc,
> > +					  drm->mode_config.num_connector);
> > +
> > +	if (IS_ERR(hdlcd->fbdev)) {
> > +		ret = PTR_ERR(hdlcd->fbdev);
> > +		hdlcd->fbdev = NULL;
> > +		goto err_fbdev;
> > +	}
> > +
> > +	return 0;
> > +
> > +err_fbdev:
> > +	drm_kms_helper_poll_fini(drm);
> > +	drm_mode_config_cleanup(drm);
> > +	drm_vblank_cleanup(drm);
> > +err_vblank:
> > +	component_unbind_all(dev, drm);
> > +err_unregister:
> > +	drm_dev_unregister(drm);
> > +err_unload:
> > +	pm_runtime_get_sync(drm->dev);
> > +	drm_irq_uninstall(drm);
> > +	pm_runtime_put_sync(drm->dev);
> > +	pm_runtime_disable(drm->dev);
> > +	of_reserved_mem_device_release(drm->dev);
> > +	devm_clk_put(dev, hdlcd->clk);
> > +err_free:
> > +	drm_dev_unref(drm);
> > +
> > +	return ret;
> > +}
> > +
> > +static void hdlcd_drm_unbind(struct device *dev)
> > +{
> > +	struct drm_device *drm = dev_get_drvdata(dev);
> > +	struct hdlcd_drm_private *hdlcd = drm->dev_private;
> > +
> > +	if (hdlcd->fbdev) {
> > +		drm_fbdev_cma_fini(hdlcd->fbdev);
> > +		hdlcd->fbdev = NULL;
> > +	}
> > +	drm_kms_helper_poll_fini(drm);
> > +	component_unbind_all(dev, drm);
> > +	drm_vblank_cleanup(drm);
> > +	pm_runtime_get_sync(drm->dev);
> > +	drm_irq_uninstall(drm);
> > +	pm_runtime_put_sync(drm->dev);
> > +	pm_runtime_disable(drm->dev);
> > +	of_reserved_mem_device_release(drm->dev);
> > +	if (!IS_ERR(hdlcd->clk)) {
> > +		devm_clk_put(drm->dev, hdlcd->clk);
> > +		hdlcd->clk = NULL;
> > +	}
> > +	drm_mode_config_cleanup(drm);
> > +	drm_dev_unregister(drm);
> > +	drm_dev_unref(drm);
> > +	drm->dev_private = NULL;
> > +	dev_set_drvdata(dev, NULL);
> > +}
> > +
> > +static const struct component_master_ops hdlcd_master_ops = {
> > +	.add_components	= hdlcd_add_components,
> > +	.bind		= hdlcd_drm_bind,
> > +	.unbind		= hdlcd_drm_unbind,
> > +};
> > +
> > +static int hdlcd_probe(struct platform_device *pdev)
> > +{
> > +	return component_master_add(&pdev->dev, &hdlcd_master_ops);
> > +}
> > +
> > +static int hdlcd_remove(struct platform_device *pdev)
> > +{
> > +	component_master_del(&pdev->dev, &hdlcd_master_ops);
> > +	return 0;
> > +}
> > +
> > +static const struct of_device_id  hdlcd_of_match[] = {
> > +	{ .compatible	= "arm,hdlcd" },
> > +	{},
> > +};
> > +MODULE_DEVICE_TABLE(of, hdlcd_of_match);
> > +
> > +static int hdlcd_pm_suspend(struct device *dev)
> > +{
> > +	struct drm_device *drm = dev_get_drvdata(dev);
> > +	struct drm_crtc *crtc;
> > +
> > +	if (pm_runtime_suspended(dev))
> > +		return 0;
> > +
> > +	drm_modeset_lock_all(drm);
> > +	list_for_each_entry(crtc, &drm->mode_config.crtc_list, head)
> > +		hdlcd_crtc_suspend(crtc);
> > +	drm_modeset_unlock_all(drm);
> > +	return 0;
> > +}
> > +
> > +static int hdlcd_pm_resume(struct device *dev)
> > +{
> > +	struct drm_device *drm = dev_get_drvdata(dev);
> > +	struct drm_crtc *crtc;
> > +
> > +	if (!pm_runtime_suspended(dev))
> > +		return 0;
> > +
> > +	drm_modeset_lock_all(drm);
> > +	list_for_each_entry(crtc, &drm->mode_config.crtc_list, head)
> > +		hdlcd_crtc_resume(crtc);
> > +	drm_modeset_unlock_all(drm);
> > +	return 0;
> > +}
> > +
> > +static SIMPLE_DEV_PM_OPS(hdlcd_pm_ops, hdlcd_pm_suspend, hdlcd_pm_resume);
> > +
> > +static struct platform_driver hdlcd_platform_driver = {
> > +	.probe		= hdlcd_probe,
> > +	.remove		= hdlcd_remove,
> > +	.driver	= {
> > +		.name = "hdlcd",
> > +		.pm = &hdlcd_pm_ops,
> > +		.of_match_table	= hdlcd_of_match,
> > +	},
> > +};
> > +
> > +module_platform_driver(hdlcd_platform_driver);
> > +
> > +MODULE_AUTHOR("Liviu Dudau");
> > +MODULE_DESCRIPTION("ARM HDLCD DRM driver");
> > +MODULE_LICENSE("GPL v2");
> > diff --git a/drivers/gpu/drm/arm/hdlcd_drv.h b/drivers/gpu/drm/arm/hdlcd_drv.h
> > new file mode 100644
> > index 0000000..f2eedfb
> > --- /dev/null
> > +++ b/drivers/gpu/drm/arm/hdlcd_drv.h
> > @@ -0,0 +1,42 @@
> > +/*
> > + *  ARM HDLCD Controller register definition
> > + */
> > +
> > +#ifndef __HDLCD_DRV_H__
> > +#define __HDLCD_DRV_H__
> > +
> > +struct hdlcd_drm_private {
> > +	void __iomem			*mmio;
> > +	struct clk			*clk;
> > +	struct drm_fbdev_cma		*fbdev;
> > +	struct drm_framebuffer		*fb;
> > +	struct drm_pending_vblank_event	*event;
> > +	struct drm_crtc			crtc;
> > +	struct drm_plane		*plane;
> > +#ifdef CONFIG_DEBUG_FS
> > +	atomic_t buffer_underrun_count;
> > +	atomic_t bus_error_count;
> > +	atomic_t vsync_count;
> > +	atomic_t dma_end_count;
> > +#endif
> > +};
> > +
> > +#define crtc_to_hdlcd_priv(x)	container_of(x, struct hdlcd_drm_private, crtc)
> > +
> > +static inline void hdlcd_write(struct hdlcd_drm_private *hdlcd,
> > +			       unsigned int reg, u32 value)
> > +{
> > +	writel(value, hdlcd->mmio + reg);
> > +}
> > +
> > +static inline u32 hdlcd_read(struct hdlcd_drm_private *hdlcd, unsigned int reg)
> > +{
> > +	return readl(hdlcd->mmio + reg);
> > +}
> > +
> > +int hdlcd_setup_crtc(struct drm_device *dev);
> > +void hdlcd_set_scanout(struct hdlcd_drm_private *hdlcd);
> > +void hdlcd_crtc_suspend(struct drm_crtc *crtc);
> > +void hdlcd_crtc_resume(struct drm_crtc *crtc);
> > +
> > +#endif /* __HDLCD_DRV_H__ */
> > diff --git a/drivers/gpu/drm/arm/hdlcd_regs.h b/drivers/gpu/drm/arm/hdlcd_regs.h
> > new file mode 100644
> > index 0000000..66799eb
> > --- /dev/null
> > +++ b/drivers/gpu/drm/arm/hdlcd_regs.h
> > @@ -0,0 +1,87 @@
> > +/*
> > + * Copyright (C) 2013,2014 ARM Limited
> > + *
> > + * This file is subject to the terms and conditions of the GNU General Public
> > + * License.  See the file COPYING in the main directory of this archive
> > + * for more details.
> > + *
> > + *  ARM HDLCD Controller register definition
> > + */
> > +
> > +#ifndef __HDLCD_REGS_H__
> > +#define __HDLCD_REGS_H__
> > +
> > +/* register offsets */
> > +#define HDLCD_REG_VERSION		0x0000	/* ro */
> > +#define HDLCD_REG_INT_RAWSTAT		0x0010	/* rw */
> > +#define HDLCD_REG_INT_CLEAR		0x0014	/* wo */
> > +#define HDLCD_REG_INT_MASK		0x0018	/* rw */
> > +#define HDLCD_REG_INT_STATUS		0x001c	/* ro */
> > +#define HDLCD_REG_FB_BASE		0x0100	/* rw */
> > +#define HDLCD_REG_FB_LINE_LENGTH	0x0104	/* rw */
> > +#define HDLCD_REG_FB_LINE_COUNT		0x0108	/* rw */
> > +#define HDLCD_REG_FB_LINE_PITCH		0x010c	/* rw */
> > +#define HDLCD_REG_BUS_OPTIONS		0x0110	/* rw */
> > +#define HDLCD_REG_V_SYNC		0x0200	/* rw */
> > +#define HDLCD_REG_V_BACK_PORCH		0x0204	/* rw */
> > +#define HDLCD_REG_V_DATA		0x0208	/* rw */
> > +#define HDLCD_REG_V_FRONT_PORCH		0x020c	/* rw */
> > +#define HDLCD_REG_H_SYNC		0x0210	/* rw */
> > +#define HDLCD_REG_H_BACK_PORCH		0x0214	/* rw */
> > +#define HDLCD_REG_H_DATA		0x0218	/* rw */
> > +#define HDLCD_REG_H_FRONT_PORCH		0x021c	/* rw */
> > +#define HDLCD_REG_POLARITIES		0x0220	/* rw */
> > +#define HDLCD_REG_COMMAND		0x0230	/* rw */
> > +#define HDLCD_REG_PIXEL_FORMAT		0x0240	/* rw */
> > +#define HDLCD_REG_RED_SELECT		0x0244	/* rw */
> > +#define HDLCD_REG_GREEN_SELECT		0x0248	/* rw */
> > +#define HDLCD_REG_BLUE_SELECT		0x024c	/* rw */
> > +
> > +/* version */
> > +#define HDLCD_PRODUCT_ID		0x1CDC0000
> > +#define HDLCD_PRODUCT_MASK		0xFFFF0000
> > +#define HDLCD_VERSION_MAJOR_MASK	0x0000FF00
> > +#define HDLCD_VERSION_MINOR_MASK	0x000000FF
> > +
> > +/* interrupts */
> > +#define HDLCD_INTERRUPT_DMA_END		(1 << 0)
> > +#define HDLCD_INTERRUPT_BUS_ERROR	(1 << 1)
> > +#define HDLCD_INTERRUPT_VSYNC		(1 << 2)
> > +#define HDLCD_INTERRUPT_UNDERRUN	(1 << 3)
> > +#define HDLCD_DEBUG_INT_MASK		(HDLCD_INTERRUPT_DMA_END |  \
> > +					HDLCD_INTERRUPT_BUS_ERROR | \
> > +					HDLCD_INTERRUPT_UNDERRUN)
> > +
> > +/* polarities */
> > +#define HDLCD_POLARITY_VSYNC		(1 << 0)
> > +#define HDLCD_POLARITY_HSYNC		(1 << 1)
> > +#define HDLCD_POLARITY_DATAEN		(1 << 2)
> > +#define HDLCD_POLARITY_DATA		(1 << 3)
> > +#define HDLCD_POLARITY_PIXELCLK		(1 << 4)
> > +
> > +/* commands */
> > +#define HDLCD_COMMAND_DISABLE		(0 << 0)
> > +#define HDLCD_COMMAND_ENABLE		(1 << 0)
> > +
> > +/* pixel format */
> > +#define HDLCD_PIXEL_FMT_LITTLE_ENDIAN	(0 << 31)
> > +#define HDLCD_PIXEL_FMT_BIG_ENDIAN	(1 << 31)
> > +#define HDLCD_BYTES_PER_PIXEL_MASK	(3 << 3)
> > +
> > +/* bus options */
> > +#define HDLCD_BUS_BURST_MASK		0x01f
> > +#define HDLCD_BUS_MAX_OUTSTAND		0xf00
> > +#define HDLCD_BUS_BURST_NONE		(0 << 0)
> > +#define HDLCD_BUS_BURST_1		(1 << 0)
> > +#define HDLCD_BUS_BURST_2		(1 << 1)
> > +#define HDLCD_BUS_BURST_4		(1 << 2)
> > +#define HDLCD_BUS_BURST_8		(1 << 3)
> > +#define HDLCD_BUS_BURST_16		(1 << 4)
> > +
> > +/* Max resolution supported is 4096x4096, 32bpp */
> > +#define HDLCD_MAX_XRES			4096
> > +#define HDLCD_MAX_YRES			4096
> > +
> > +#define NR_PALETTE			256
> > +
> > +#endif /* __HDLCD_REGS_H__ */
> > -- 
> > 2.6.2
> > 
> > _______________________________________________
> > dri-devel mailing list
> > dri-devel@lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/dri-devel
> 
> -- 
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/dri-devel

On Wed, Dec 02, 2015 at 05:21:44PM +0000, Daniel Stone wrote:
> Hi Liviu,

Hi Daniel,

> 
> On 2 December 2015 at 12:23, Liviu Dudau <Liviu.Dudau@arm.com> wrote:
> > +       if (irq_status & HDLCD_INTERRUPT_VSYNC) {
> > +               unsigned long flags;
> > +
> > +               drm_handle_vblank(drm, 0);
> > +
> > +               spin_lock_irqsave(&drm->event_lock, flags);
> > +               if (hdlcd->event) {
> > +                       drm_send_vblank_event(drm, hdlcd->event->pipe, hdlcd->event);
> > +                       drm_crtc_vblank_put(&hdlcd->crtc);
> > +                       hdlcd->event = NULL;
> > +               }
> > +               spin_unlock_irqrestore(&drm->event_lock, flags);
> > +       }
> 
> As with VC4 and Rockchip, you're missing a ->preclose handler in your
> drm_drv, to make sure that you don't try to send events to a dead
> client (which causes an OOPS):
> https://git.collabora.com/cgit/user/daniels/linux.git/commit/?h=wip/4.4.x/rockchip-drm-fixes&id=d14f21bcd7
> (and its parent)
 
Thanks for reviewing this!

I do acknowledge your concerns and you might correct my understanding on
how atomic DRM works, but I believe in this case we should be safe. The
event stored in hdlcd->event is taken out of the crtc->state->event during
the crtc->atomic_begin() callback. If the client is dead the callback should
not be called, so that's how we avoid the OOPS.

> Also, is there anything preventing clients from submitting multiple
> pageflips before the event is sent? I couldn't see anything from a
> quick look, so you could have the situation of:
>   - client submits pageflip, event 1 stored to hdlcd->event
>   - client submits pageflip, event 2 stored to hdlcd->event
>   - vblank arrives, event 2 is sent
>   - event 1 has disappeared and been leaked

As for multiple events being submitted before vsync interrupt happening: given
that the event is plucked out of the crtc->state, is that possible? And if so,
is there a case where having the later event overwrite the earlier one a desired
outcome?

> 
> Cheers,
> Daniel
> 

Best regards,
Liviu