Commit 5d363120 authored by Pawel Laszczak's avatar Pawel Laszczak Committed by Felipe Balbi
Browse files

usb: gadget: Fix issue with config_ep_by_speed function 



This patch adds new config_ep_by_speed_and_alt function which
extends the config_ep_by_speed about alt parameter.
This additional parameter allows to find proper usb_ss_ep_comp_descriptor.

Problem has appeared during testing f_tcm (BOT/UAS) driver function.

f_tcm function for SS use array of headers for both  BOT/UAS alternate
setting:

static struct usb_descriptor_header *uasp_ss_function_desc[] = {
        (struct usb_descriptor_header *) &bot_intf_desc,
        (struct usb_descriptor_header *) &uasp_ss_bi_desc,
        (struct usb_descriptor_header *) &bot_bi_ep_comp_desc,
        (struct usb_descriptor_header *) &uasp_ss_bo_desc,
        (struct usb_descriptor_header *) &bot_bo_ep_comp_desc,

        (struct usb_descriptor_header *) &uasp_intf_desc,
        (struct usb_descriptor_header *) &uasp_ss_bi_desc,
        (struct usb_descriptor_header *) &uasp_bi_ep_comp_desc,
        (struct usb_descriptor_header *) &uasp_bi_pipe_desc,
        (struct usb_descriptor_header *) &uasp_ss_bo_desc,
        (struct usb_descriptor_header *) &uasp_bo_ep_comp_desc,
        (struct usb_descriptor_header *) &uasp_bo_pipe_desc,
        (struct usb_descriptor_header *) &uasp_ss_status_desc,
        (struct usb_descriptor_header *) &uasp_status_in_ep_comp_desc,
        (struct usb_descriptor_header *) &uasp_status_pipe_desc,
        (struct usb_descriptor_header *) &uasp_ss_cmd_desc,
        (struct usb_descriptor_header *) &uasp_cmd_comp_desc,
        (struct usb_descriptor_header *) &uasp_cmd_pipe_desc,
        NULL,
};

The first 5 descriptors are associated with BOT alternate setting,
and others are associated with UAS.

During handling UAS alternate setting f_tcm driver invokes
config_ep_by_speed and this function sets incorrect companion endpoint
descriptor in usb_ep object.

Instead setting ep->comp_desc to uasp_bi_ep_comp_desc function in this
case set ep->comp_desc to uasp_ss_bi_desc.

This is due to the fact that it searches endpoint based on endpoint
address:

        for_each_ep_desc(speed_desc, d_spd) {
                chosen_desc = (struct usb_endpoint_descriptor *)*d_spd;
                if (chosen_desc->bEndpoitAddress == _ep->address)
                        goto ep_found;
        }

And in result it uses the descriptor from BOT alternate setting
instead UAS.

Finally, it causes that controller driver during enabling endpoints
detect that just enabled endpoint for bot.

Signed-off-by: default avatarJayshri Pawar <jpawar@cadence.com>
Signed-off-by: default avatarPawel Laszczak <pawell@cadence.com>
Signed-off-by: default avatarFelipe Balbi <balbi@kernel.org>
parent 8b5b9adb

drivers/usb/gadget/composite.c

+61 −17
Original line number Diff line number Diff line
@@ -96,40 +96,43 @@ function_descriptors(struct usb_function *f, 
}



/**

 * next_ep_desc() - advance to the next EP descriptor

 * next_desc() - advance to the next desc_type descriptor

 * @t: currect pointer within descriptor array

 * @desc_type: descriptor type

 *

 * Return: next EP descriptor or NULL

 * Return: next desc_type descriptor or NULL

 *

 * Iterate over @t until either EP descriptor found or

 * Iterate over @t until either desc_type descriptor found or

 * NULL (that indicates end of list) encountered

 */

static struct usb_descriptor_header**

next_ep_desc(struct usb_descriptor_header **t)

next_desc(struct usb_descriptor_header **t, u8 desc_type)

{

	for (; *t; t++) {

		if ((*t)->bDescriptorType == USB_DT_ENDPOINT)

		if ((*t)->bDescriptorType == desc_type)

			return t;

	}

	return NULL;

}



/*

 * for_each_ep_desc()- iterate over endpoint descriptors in the

 * for_each_desc() - iterate over desc_type descriptors in the

 * descriptors list

 * @start: pointer within descriptor array.

 * @ep_desc:	endpoint descriptor to use as the loop cursor

 * @iter_desc: desc_type descriptor to use as the loop cursor

 * @desc_type: wanted descriptr type

 */

#define for_each_ep_desc(start, ep_desc) \

	for (ep_desc = next_ep_desc(start); \

	      ep_desc; ep_desc = next_ep_desc(ep_desc+1))

#define for_each_desc(start, iter_desc, desc_type) \

	for (iter_desc = next_desc(start, desc_type); \

	     iter_desc; iter_desc = next_desc(iter_desc + 1, desc_type))



/**

 * config_ep_by_speed() - configures the given endpoint

 * config_ep_by_speed_and_alt() - configures the given endpoint

 * according to gadget speed.

 * @g: pointer to the gadget

 * @f: usb function

 * @_ep: the endpoint to configure

 * @alt: alternate setting number

 *

 * Return: error code, 0 on success

 *
@@ -142,11 +145,13 @@ next_ep_desc(struct usb_descriptor_header **t) 
 * Note: the supplied function should hold all the descriptors

 * for supported speeds

 */

int config_ep_by_speed(struct usb_gadget *g,

int config_ep_by_speed_and_alt(struct usb_gadget *g,

				struct usb_function *f,

			struct usb_ep *_ep)

				struct usb_ep *_ep,

				u8 alt)

{

	struct usb_endpoint_descriptor *chosen_desc = NULL;

	struct usb_interface_descriptor *int_desc = NULL;

	struct usb_descriptor_header **speed_desc = NULL;



	struct usb_ss_ep_comp_descriptor *comp_desc = NULL;
@@ -182,8 +187,21 @@ int config_ep_by_speed(struct usb_gadget *g, 
	default:

		speed_desc = f->fs_descriptors;

	}



	/* find correct alternate setting descriptor */

	for_each_desc(speed_desc, d_spd, USB_DT_INTERFACE) {

		int_desc = (struct usb_interface_descriptor *)*d_spd;



		if (int_desc->bAlternateSetting == alt) {

			speed_desc = d_spd;

			goto intf_found;

		}

	}

	return -EIO;



intf_found:

	/* find descriptors */

	for_each_ep_desc(speed_desc, d_spd) {

	for_each_desc(speed_desc, d_spd, USB_DT_ENDPOINT) {

		chosen_desc = (struct usb_endpoint_descriptor *)*d_spd;

		if (chosen_desc->bEndpointAddress == _ep->address)

			goto ep_found;
@@ -237,6 +255,32 @@ ep_found: 
	}

	return 0;

}

EXPORT_SYMBOL_GPL(config_ep_by_speed_and_alt);



/**

 * config_ep_by_speed() - configures the given endpoint

 * according to gadget speed.

 * @g: pointer to the gadget

 * @f: usb function

 * @_ep: the endpoint to configure

 *

 * Return: error code, 0 on success

 *

 * This function chooses the right descriptors for a given

 * endpoint according to gadget speed and saves it in the

 * endpoint desc field. If the endpoint already has a descriptor

 * assigned to it - overwrites it with currently corresponding

 * descriptor. The endpoint maxpacket field is updated according

 * to the chosen descriptor.

 * Note: the supplied function should hold all the descriptors

 * for supported speeds

 */

int config_ep_by_speed(struct usb_gadget *g,

			struct usb_function *f,

			struct usb_ep *_ep)

{

	return config_ep_by_speed_and_alt(g, f, _ep, 0);

}

EXPORT_SYMBOL_GPL(config_ep_by_speed);



/**

include/linux/usb/composite.h

+3 −0
Original line number Diff line number Diff line
@@ -249,6 +249,9 @@ int usb_function_activate(struct usb_function *); 


int usb_interface_id(struct usb_configuration *, struct usb_function *);



int config_ep_by_speed_and_alt(struct usb_gadget *g, struct usb_function *f,

				struct usb_ep *_ep, u8 alt);



int config_ep_by_speed(struct usb_gadget *g, struct usb_function *f,

			struct usb_ep *_ep);

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