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usb: gadget: composite: add req_match method to usb_function

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Non-standard requests can encode the actual interface number in a
non-standard way. For example composite_setup() assumes
that it is w_index && 0xFF, but the printer function encodes the interface
number in a context-dependet way (either w_index or w_index >> 8).
This can lead to such requests being directed to wrong functions.

This patch adds req_match() method to usb_function. Its purpose is to
verify that a given request can be handled by a given function.
If any function within a configuration provides the method and it returns
true, then it is assumed that the right function is found.

If a function uses req_match(), it should try as hard as possible to
determine if the request is meant for it.

If no functions in a configuration provide req_match or none of them
returns true, then fall back to the usual approach.

Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
This commit is contained in:
Andrzej Pietrasiewicz 2015-03-03 10:52:23 +01:00 committed by Felipe Balbi
parent 143d53e10e
commit f563d23090
2 changed files with 8 additions and 1 deletions
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6
drivers/usb/gadget/composite.c
View File

@ -1758,6 +1758,10 @@ unknown:
* take such requests too, if that's ever needed: to work
* in config 0, etc.
*/
list_for_each_entry(f, &cdev->config->functions, list)
if (f->req_match && f->req_match(f, ctrl))
goto try_fun_setup;
f = NULL;
switch (ctrl->bRequestType & USB_RECIP_MASK) {
case USB_RECIP_INTERFACE:
if (!cdev->config || intf >= MAX_CONFIG_INTERFACES)
@ -1775,7 +1779,7 @@ unknown:
f = NULL;
break;
}
try_fun_setup:
if (f && f->setup)
value = f->setup(f, ctrl);
else {

3
include/linux/usb/composite.h
View File

@ -148,6 +148,7 @@ struct usb_os_desc_table {
* @disable: (REQUIRED) Indicates the function should be disabled. Reasons
* include host resetting or reconfiguring the gadget, and disconnection.
* @setup: Used for interface-specific control requests.
* @req_match: Tests if a given class request can be handled by this function.
* @suspend: Notifies functions when the host stops sending USB traffic.
* @resume: Notifies functions when the host restarts USB traffic.
* @get_status: Returns function status as a reply to
@ -213,6 +214,8 @@ struct usb_function {
void (*disable)(struct usb_function *);
int (*setup)(struct usb_function *,
const struct usb_ctrlrequest *);
bool (*req_match)(struct usb_function *,
const struct usb_ctrlrequest *);
void (*suspend)(struct usb_function *);
void (*resume)(struct usb_function *);