[PATCH 4.9 058/191] usb: gadget: Fix issue with config_ep_by_speed function

Sasha Levin
2020-06-29T19:26:34Z

From: Pawel Laszczak <pawell@cadence.com>

[ Upstream commit 5d363120aa548ba52d58907a295eee25f8207ed2 ]

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: Jayshri Pawar <jpawar@cadence.com>
Signed-off-by: Pawel Laszczak <pawell@cadence.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/usb/gadget/composite.c | 78 ++++++++++++++++++++++++++--------
include/linux/usb/composite.h | 3 ++
2 files changed, 64 insertions(+), 17 deletions(-)

diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index 2e545d0250309..5a1723d99fe51 100644
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -100,40 +100,43 @@ 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
- * descriptors list
- * @start: pointer within descriptor array.
- * @ep_desc: endpoint descriptor to use as the loop cursor
+ * for_each_desc() - iterate over desc_type descriptors in the
+ * descriptors list
+ * @start: pointer within descriptor array.
+ * @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
*
@@ -146,11 +149,13 @@ 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,
- struct usb_function *f,
- struct usb_ep *_ep)
+int config_ep_by_speed_and_alt(struct usb_gadget *g,
+ struct usb_function *f,
+ 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;
@@ -186,8 +191,21 @@ 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;
@@ -240,6 +258,32 @@ int config_ep_by_speed(struct usb_gadget *g,
}
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);

/**
diff --git a/include/linux/usb/composite.h b/include/linux/usb/composite.h
index 667d20454a21d..0ec7185e5ddfd 100644
--- a/include/linux/usb/composite.h
+++ b/include/linux/usb/composite.h
@@ -248,6 +248,9 @@ 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);

--
2.25.1