From patchwork Wed Dec 7 10:06:51 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Benjamin Gaignard X-Patchwork-Id: 86994 Delivered-To: patch@linaro.org Received: by 10.140.20.101 with SMTP id 92csp233419qgi; Wed, 7 Dec 2016 02:08:23 -0800 (PST) X-Received: by 10.84.217.216 with SMTP id d24mr145681401plj.101.1481105303783; Wed, 07 Dec 2016 02:08:23 -0800 (PST) Return-Path: Received: from gabe.freedesktop.org (gabe.freedesktop.org. [131.252.210.177]) by mx.google.com with ESMTPS id l7si23393277pga.269.2016.12.07.02.08.23 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 07 Dec 2016 02:08:23 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of dri-devel-bounces@lists.freedesktop.org designates 131.252.210.177 as permitted sender) client-ip=131.252.210.177; Authentication-Results: mx.google.com; dkim=neutral (body hash did not verify) header.i=@linaro.org; spf=pass (google.com: best guess record for domain of dri-devel-bounces@lists.freedesktop.org designates 131.252.210.177 as permitted sender) smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org; dmarc=fail (p=NONE dis=NONE) header.from=linaro.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 296666E52D; Wed, 7 Dec 2016 10:08:08 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from mail-wj0-x22a.google.com (mail-wj0-x22a.google.com [IPv6:2a00:1450:400c:c01::22a]) by gabe.freedesktop.org (Postfix) with ESMTPS id 12C026E52A for ; Wed, 7 Dec 2016 10:08:03 +0000 (UTC) Received: by mail-wj0-x22a.google.com with SMTP id v7so355810846wjy.2 for ; Wed, 07 Dec 2016 02:08:03 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=G42ynN0EP9cY39Xi7tirWnhjbOcABGNV14PQQhR6k+g=; b=kSsaypnbjzc294wVz9su29ectYMbVe2h6fxb2WQd0kz+aTkx6WAu1S0+qVmM7gOZ+f 9FAVOH9Jb3LL+E2t1mvPX+K5gpvF8enlYo2WLpkH7ees6munIYXylYTo3Soxe1ib35uG V6dSg8K+vQtK0Sln4xo1/Q866296IZOC+/+sA= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=G42ynN0EP9cY39Xi7tirWnhjbOcABGNV14PQQhR6k+g=; b=Ohr3OPChEhOdvXGiCWv5CbS7Mddm9kL7aj0G2DOc5/4xy3rz8pR2BWEAdL0odyHaaZ sA/iSlRKVLgCr+9T6LhUnx7Q0gvpvOeFETRhz/8MwvychKrBaOvAtRlumOLmfpNBo4E6 YNClda0V6E0WqGNCOvMj/57+K2Cp0Cfux/F2NNjdIIV68w9qvFbUEYiwfv0Ea643ZKz8 uJ6JQ/QjX+nZI6MIX7Z3ZL34+2q8AmGxf5VDN69Mbe9zM/N6ejksD8Ws2l7vhnXdSGDY D6jmukQKyXu3/PpLAkiaXCvOIHm1xC8mCclQPRIjr4U+rvCU3LVPGLHgjJzkxVklUo/Q TF0g== X-Gm-Message-State: AKaTC00KRzeIr6FfJY6z+fntQXZFt+BZkPnF/6TwiKn3091HcHcwMUCTBRsSIsFga0HqYNc7 X-Received: by 10.194.146.131 with SMTP id tc3mr60008627wjb.129.1481105281231; Wed, 07 Dec 2016 02:08:01 -0800 (PST) Received: from lmenx321.st.com. ([80.215.165.156]) by smtp.gmail.com with ESMTPSA id x140sm8748561wme.19.2016.12.07.02.07.59 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Wed, 07 Dec 2016 02:08:00 -0800 (PST) From: Benjamin Gaignard To: dri-devel@lists.freedesktop.org, airlied@redhat.com, daniel@ffwll.ch, laurent.pinchart@ideasonboard.com, michel@daenzer.net Subject: [PATCH v4 4/4] drm: allow to use mmuless SoC Date: Wed, 7 Dec 2016 11:06:51 +0100 Message-Id: <1481105211-18020-5-git-send-email-benjamin.gaignard@linaro.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1481105211-18020-1-git-send-email-benjamin.gaignard@linaro.org> References: <1481105211-18020-1-git-send-email-benjamin.gaignard@linaro.org> Cc: yannick.fertre@st.com, linaro-kernel@lists.linaro.org, philippe.cornu@st.com X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Some SoC without MMU have display driver where a drm/kms driver could be implemented. Before doing such kind of thing drm/kms must allow to use mmuless devices. This patch propose to remove MMU configuration flag and add a cma helper function to help implementing mmuless display driver version 4: - add documentation about drm_gem_cma_get_unmapped_area() - stub it MMU case Signed-off-by: Benjamin Gaignard Reviewed-by: Laurent Pinchart --- Documentation/gpu/drm-mm.rst | 11 ++++++ drivers/gpu/drm/Kconfig | 4 +-- drivers/gpu/drm/drm_gem_cma_helper.c | 69 ++++++++++++++++++++++++++++++++++++ include/drm/drm_gem_cma_helper.h | 17 +++++++++ 4 files changed, 99 insertions(+), 2 deletions(-) diff --git a/Documentation/gpu/drm-mm.rst b/Documentation/gpu/drm-mm.rst index bca8085..6e7efab 100644 --- a/Documentation/gpu/drm-mm.rst +++ b/Documentation/gpu/drm-mm.rst @@ -303,6 +303,17 @@ created. Drivers that want to map the GEM object upfront instead of handling page faults can implement their own mmap file operation handler. +For platforms without MMU GEM care provides a helper method +:c:func:`drm_gem_cma_get_unmapped_area`. The mmap() routines will call +this to get a proposed address for the mapping. + +To use :c:func:`drm_gem_cma_get_unmapped_area`, drivers must fill the +struct :c:type:`struct file_operations ` get_unmapped_area +field with a pointer on :c:func:`drm_gem_cma_get_unmapped_area`. + +More detailed information about get_unmapped_area can be found in +Documentation/nommu-mmap.txt + Memory Coherency ---------------- diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig index 83ac815..0eae4ad 100644 --- a/drivers/gpu/drm/Kconfig +++ b/drivers/gpu/drm/Kconfig @@ -6,7 +6,7 @@ # menuconfig DRM tristate "Direct Rendering Manager (XFree86 4.1.0 and higher DRI support)" - depends on (AGP || AGP=n) && !EMULATED_CMPXCHG && MMU && HAS_DMA + depends on (AGP || AGP=n) && !EMULATED_CMPXCHG && HAS_DMA select HDMI select FB_CMDLINE select I2C @@ -98,7 +98,7 @@ config DRM_LOAD_EDID_FIRMWARE config DRM_TTM tristate - depends on DRM + depends on DRM && MMU help GPU memory management subsystem for devices with multiple GPU memory types. Will be enabled automatically if a device driver diff --git a/drivers/gpu/drm/drm_gem_cma_helper.c b/drivers/gpu/drm/drm_gem_cma_helper.c index 1d6c335..01016b1 100644 --- a/drivers/gpu/drm/drm_gem_cma_helper.c +++ b/drivers/gpu/drm/drm_gem_cma_helper.c @@ -358,6 +358,75 @@ int drm_gem_cma_mmap(struct file *filp, struct vm_area_struct *vma) } EXPORT_SYMBOL_GPL(drm_gem_cma_mmap); +#ifndef CONFIG_MMU +/** + * drm_gem_cma_get_unmapped_area - propose address for mapping in noMMU cases + * @filp: file object + * @addr: memory address + * @len: buffer size + * @pgoff: page offset + * @flags: memory flags + * + * This function is used in noMMU platforms to propose address mapping + * for a given buffer. + * + * Returns: + * mapping address on success or a negative error code on failure + */ +unsigned long drm_gem_cma_get_unmapped_area(struct file *filp, + unsigned long addr, + unsigned long len, + unsigned long pgoff, + unsigned long flags) +{ + struct drm_gem_cma_object *cma_obj; + struct drm_gem_object *obj = NULL; + struct drm_file *priv = filp->private_data; + struct drm_device *dev = priv->minor->dev; + struct drm_vma_offset_node *node; + + if (drm_device_is_unplugged(dev)) + return -ENODEV; + + drm_vma_offset_lock_lookup(dev->vma_offset_manager); + node = drm_vma_offset_exact_lookup_locked(dev->vma_offset_manager, + pgoff, + len >> PAGE_SHIFT); + if (likely(node)) { + obj = container_of(node, struct drm_gem_object, vma_node); + /* + * When the object is being freed, after it hits 0-refcnt it + * proceeds to tear down the object. In the process it will + * attempt to remove the VMA offset and so acquire this + * mgr->vm_lock. Therefore if we find an object with a 0-refcnt + * that matches our range, we know it is in the process of being + * destroyed and will be freed as soon as we release the lock - + * so we have to check for the 0-refcnted object and treat it as + * invalid. + */ + if (!kref_get_unless_zero(&obj->refcount)) + obj = NULL; + } + + drm_vma_offset_unlock_lookup(dev->vma_offset_manager); + + if (!obj) + return -EINVAL; + + if (!drm_vma_node_is_allowed(node, priv)) { + drm_gem_object_unreference_unlocked(obj); + return -EACCES; + } + + cma_obj = to_drm_gem_cma_obj(obj); + + drm_gem_object_unreference_unlocked(obj); + + return cma_obj->vaddr ? (unsigned long)cma_obj->vaddr : -EINVAL; +} +EXPORT_SYMBOL_GPL(drm_gem_cma_get_unmapped_area); +#endif + #ifdef CONFIG_DEBUG_FS /** * drm_gem_cma_describe - describe a CMA GEM object for debugfs diff --git a/include/drm/drm_gem_cma_helper.h b/include/drm/drm_gem_cma_helper.h index acd6af8..180b586 100644 --- a/include/drm/drm_gem_cma_helper.h +++ b/include/drm/drm_gem_cma_helper.h @@ -53,6 +53,23 @@ struct drm_gem_cma_object *drm_gem_cma_create(struct drm_device *drm, extern const struct vm_operations_struct drm_gem_cma_vm_ops; +#ifndef CONFIG_MMU +unsigned long drm_gem_cma_get_unmapped_area(struct file *filp, + unsigned long addr, + unsigned long len, + unsigned long pgoff, + unsigned long flags); +#else +unsigned long drm_gem_cma_get_unmapped_area(struct file *filp, + unsigned long addr, + unsigned long len, + unsigned long pgoff, + unsigned long flags) +{ + return -EINVAL; +} +#endif + #ifdef CONFIG_DEBUG_FS void drm_gem_cma_describe(struct drm_gem_cma_object *obj, struct seq_file *m); #endif