[v2,3/4] usb: gadget: legacy: add 9pfs multi gadget

Add the newly introduced 9pfs transport gadget interface with an new
multi composed gadget together with acm and eem.

When using this legacy module, it is also possible to
mount the 9PFS usb dir as root filesystem. Just follow the
instrucitons from Documentation/filesystems/9p.rst

Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>

---
v1 -> v2:
  - deleted the usbg 9pfs detailed instruction from commit message
  - added depends on net for NET_9P dependency
---
 drivers/usb/gadget/legacy/9pfs.c   | 268 +++++++++++++++++++++++++++++++++++++
 drivers/usb/gadget/legacy/Kconfig  |  16 +++
 drivers/usb/gadget/legacy/Makefile |   2 +
 3 files changed, 286 insertions(+)

On Fri, Feb 02, 2024 at 01:05:12AM +0100, Michael Grzeschik wrote:
> Add the newly introduced 9pfs transport gadget interface with an new
> multi composed gadget together with acm and eem.
> 
> When using this legacy module, it is also possible to
> mount the 9PFS usb dir as root filesystem. Just follow the
> instrucitons from Documentation/filesystems/9p.rst

Why are we adding new "legacy" gadgets?  What's wrong with the "correct"
api instead?  You need a lot of justification here to add something to
an api we want to one day just delete.

And can you wrap your changelog at 72 columns?


> 
> Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
> 
> ---
> v1 -> v2:
>   - deleted the usbg 9pfs detailed instruction from commit message
>   - added depends on net for NET_9P dependency
> ---
>  drivers/usb/gadget/legacy/9pfs.c   | 268 +++++++++++++++++++++++++++++++++++++
>  drivers/usb/gadget/legacy/Kconfig  |  16 +++
>  drivers/usb/gadget/legacy/Makefile |   2 +
>  3 files changed, 286 insertions(+)
> 
> diff --git a/drivers/usb/gadget/legacy/9pfs.c b/drivers/usb/gadget/legacy/9pfs.c
> new file mode 100644
> index 0000000000000..3ac7f2e92c5a3
> --- /dev/null
> +++ b/drivers/usb/gadget/legacy/9pfs.c
> @@ -0,0 +1,268 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * usb9pfs.c -- Gadget usb9pfs
> + *
> + * Copyright (C) 2023 Michael Grzeschik
> + */
> +
> +/*
> + * Gadget usb9pfs only needs two bulk endpoints, and will use the usb9pfs usb
> + * transport to mount host filesystem via usb gadget. This driver will
> + * also add one ACM and NCM interface.

Why "also"?  What are those interfaces going to be used for and what do
they have to do with 9pfs?

> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/slab.h>
> +#include <linux/device.h>
> +#include <linux/module.h>
> +#include <linux/err.h>
> +#include <linux/usb/composite.h>
> +#include <linux/netdevice.h>
> +
> +#include "u_eem.h"
> +#include "u_ether.h"
> +
> +/*-------------------------------------------------------------------------*/
> +USB_GADGET_COMPOSITE_OPTIONS();
> +
> +USB_ETHERNET_MODULE_PARAMETERS();
> +
> +/* Defines */
> +
> +#define DRIVER_VERSION_STR "v1.0"
> +#define DRIVER_VERSION_NUM 0x1000
> +
> +#define DRIVER_DESC	"Composite Gadget (9P + ACM + NCM)"
> +
> +/*-------------------------------------------------------------------------*/
> +
> +#define DRIVER_VENDOR_NUM	0x1d6b		/* Linux Foundation */
> +#define DRIVER_PRODUCT_NUM	0x0109		/* Linux-USB 9PFS Gadget */
> +
> +/*-------------------------------------------------------------------------*/
> +
> +static struct usb_device_descriptor device_desc = {
> +	.bLength =		sizeof(device_desc),
> +	.bDescriptorType =	USB_DT_DEVICE,
> +
> +	/* .bcdUSB = DYNAMIC */
> +
> +	.bDeviceClass =		USB_CLASS_MISC,
> +	.bDeviceSubClass =	2,
> +	.bDeviceProtocol =	1,
> +
> +	/* .bMaxPacketSize0 = f(hardware) */
> +
> +	/* Vendor and product id can be overridden by module parameters.  */
> +	.idVendor =		cpu_to_le16(DRIVER_VENDOR_NUM),
> +	.idProduct =		cpu_to_le16(DRIVER_PRODUCT_NUM),
> +	/* .bcdDevice = f(hardware) */
> +	/* .iManufacturer = DYNAMIC */
> +	/* .iProduct = DYNAMIC */
> +	/* NO SERIAL NUMBER */
> +	/*.bNumConfigurations =	DYNAMIC*/
> +};
> +
> +static const struct usb_descriptor_header *otg_desc[2];
> +
> +static struct usb_string strings_dev[] = {
> +	[USB_GADGET_MANUFACTURER_IDX].s = "",
> +	[USB_GADGET_PRODUCT_IDX].s = DRIVER_DESC,
> +	[USB_GADGET_SERIAL_IDX].s = "",
> +	{  }			/* end of list */
> +};
> +
> +static struct usb_gadget_strings stringtab_dev = {
> +	.language	= 0x0409,	/* en-us */
> +	.strings	= strings_dev,
> +};
> +
> +static struct usb_gadget_strings *dev_strings[] = {
> +	&stringtab_dev,
> +	NULL,
> +};
> +
> +static struct usb_configuration cdc_driver_conf = {
> +	.label          = DRIVER_DESC,
> +	.bConfigurationValue = 1,
> +	/* .iConfiguration = DYNAMIC */
> +	.bmAttributes   = USB_CONFIG_ATT_SELFPOWER,
> +};
> +
> +static struct usb_function *f_9pfs;
> +static struct usb_function_instance *fi_9pfs;
> +
> +static struct usb_function *f_acm;
> +static struct usb_function_instance *fi_acm;
> +
> +static struct usb_function *f_eem;
> +static struct usb_function_instance *fi_eem;
> +
> +static int cdc_do_config(struct usb_configuration *c)
> +{
> +	int ret;
> +
> +	if (gadget_is_otg(c->cdev->gadget)) {
> +		c->descriptors = otg_desc;
> +		c->bmAttributes |= USB_CONFIG_ATT_WAKEUP;
> +	}
> +
> +	f_9pfs = usb_get_function(fi_9pfs);
> +	if (IS_ERR(f_9pfs))
> +		return PTR_ERR(f_9pfs);
> +
> +	ret = usb_add_function(c, f_9pfs);
> +	if (ret < 0)
> +		goto err_func_9pfs;
> +
> +	f_acm = usb_get_function(fi_acm);
> +	if (IS_ERR(f_acm)) {
> +		ret = PTR_ERR(f_acm);
> +		goto err_func_acm;
> +	}
> +
> +	ret = usb_add_function(c, f_acm);
> +	if (ret)
> +		goto err_conf;
> +
> +	f_eem = usb_get_function(fi_eem);
> +	if (IS_ERR(f_eem)) {
> +		ret = PTR_ERR(f_eem);
> +		goto err_eem;
> +	}
> +
> +	ret = usb_add_function(c, f_eem);
> +	if (ret)
> +		goto err_run;
> +
> +	return 0;
> +err_run:
> +	usb_put_function(f_eem);
> +err_eem:
> +	usb_remove_function(c, f_acm);
> +err_conf:
> +	usb_put_function(f_acm);
> +err_func_acm:
> +	usb_remove_function(c, f_9pfs);
> +err_func_9pfs:
> +	usb_put_function(f_9pfs);
> +	return ret;
> +}
> +
> +static int usb9pfs_bind(struct usb_composite_dev *cdev)
> +{
> +	struct f_eem_opts	*eem_opts = NULL;
> +	int status;
> +
> +	fi_9pfs = usb_get_function_instance("usb9pfs");
> +	if (IS_ERR(fi_9pfs)) {
> +		if (PTR_ERR(fi_9pfs) == -ENOENT)
> +			return -EPROBE_DEFER;
> +		return PTR_ERR(fi_9pfs);
> +	}
> +
> +	/* set up serial link layer */
> +	fi_acm = usb_get_function_instance("acm");
> +	if (IS_ERR(fi_acm)) {
> +		if (PTR_ERR(fi_9pfs) == -ENOENT)
> +			return -EPROBE_DEFER;
> +		status = PTR_ERR(fi_acm);
> +		goto err_conf_acm;
> +	}
> +
> +	fi_eem = usb_get_function_instance("eem");
> +	if (IS_ERR(fi_eem)) {
> +		if (PTR_ERR(fi_9pfs) == -ENOENT)
> +			return -EPROBE_DEFER;
> +		status = PTR_ERR(fi_eem);
> +		goto err_conf_eem;
> +	}
> +
> +	eem_opts = container_of(fi_eem, struct f_eem_opts, func_inst);
> +
> +	gether_set_qmult(eem_opts->net, qmult);
> +	if (!gether_set_host_addr(eem_opts->net, host_addr))
> +		pr_info("using host ethernet address: %s", host_addr);
> +	if (!gether_set_dev_addr(eem_opts->net, dev_addr))
> +		pr_info("using self ethernet address: %s", dev_addr);
> +
> +	/* Allocate string descriptor numbers ... note that string
> +	 * contents can be overridden by the composite_dev glue.
> +	 */
> +	status = usb_string_ids_tab(cdev, strings_dev);
> +	if (status < 0)
> +		return status;
> +
> +	device_desc.iManufacturer = strings_dev[USB_GADGET_MANUFACTURER_IDX].id;
> +	device_desc.iProduct = strings_dev[USB_GADGET_PRODUCT_IDX].id;
> +	device_desc.iSerialNumber = strings_dev[USB_GADGET_SERIAL_IDX].id;
> +
> +	/* support OTG systems */
> +	if (gadget_is_otg(cdev->gadget)) {
> +		if (!otg_desc[0]) {
> +			struct usb_descriptor_header *usb_desc;
> +
> +			usb_desc = usb_otg_descriptor_alloc(cdev->gadget);
> +			if (!usb_desc) {
> +				status = -ENOMEM;
> +				goto err_conf_otg;
> +			}
> +			usb_otg_descriptor_init(cdev->gadget, usb_desc);
> +			otg_desc[0] = usb_desc;
> +			otg_desc[1] = NULL;
> +		}
> +	}
> +
> +	status = usb_add_config(cdev, &cdc_driver_conf, cdc_do_config);
> +	if (status)
> +		goto err_free_otg_desc;
> +
> +	usb_ep_autoconfig_reset(cdev->gadget);
> +	usb_composite_overwrite_options(cdev, &coverwrite);
> +
> +	dev_info(&cdev->gadget->dev, DRIVER_DESC " version: " DRIVER_VERSION_STR "\n");

When drivers are working properly, they are quiet.

thanks,

greg k-h

On Mon, Feb 19, 2024 at 09:02:54PM +0100, Michael Grzeschik wrote:
> Okay, What about the rest of the series? Can you just skip this patch
> then for? Or do you want me to send the series again without this
> legacy driver. There are no dependencies to this in that series.

I don't remember what the rest of this series was, it is long gone from
my review queue :(

So yes, please resend.

thanks,

greg k-h