linux/drivers/usb/gadget
Andrey Konovalov 97df5e5758 usb: raw-gadget: fix gadget endpoint selection
Currently automatic gadget endpoint selection based on required features
doesn't work. Raw Gadget tries iterating over the list of available
endpoints and finding one that has the right direction and transfer type.
Unfortunately selecting arbitrary gadget endpoints (even if they satisfy
feature requirements) doesn't work, as (depending on the UDC driver) they
might have fixed addresses, and one also needs to provide matching
endpoint addresses in the descriptors sent to the host.

The composite framework deals with this by assigning endpoint addresses
in usb_ep_autoconfig() before enumeration starts. This approach won't work
with Raw Gadget as the endpoints are supposed to be enabled after a
set_configuration/set_interface request from the host, so it's too late to
patch the endpoint descriptors that had already been sent to the host.

For Raw Gadget we take another approach. Similarly to GadgetFS, we allow
the user to make the decision as to which gadget endpoints to use.

This patch adds another Raw Gadget ioctl USB_RAW_IOCTL_EPS_INFO that
exposes information about all non-control endpoints that a currently
connected UDC has. This information includes endpoints addresses, as well
as their capabilities and limits to allow the user to choose the most
fitting gadget endpoint.

The USB_RAW_IOCTL_EP_ENABLE ioctl is updated to use the proper endpoint
validation routine usb_gadget_ep_match_desc().

These changes affect the portability of the gadgets that use Raw Gadget
when running on different UDCs. Nevertheless, as long as the user relies
on the information provided by USB_RAW_IOCTL_EPS_INFO to dynamically
choose endpoint addresses, UDC-agnostic gadgets can still be written with
Raw Gadget.

Fixes: f2c2e71764 ("usb: gadget: add raw-gadget interface")
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>
2020-05-14 12:30:17 +03:00
..
function usb: f_fs: Clear OS Extended descriptor counts to zero in ffs_data_reset() 2020-04-16 14:59:49 +02:00
legacy usb: raw-gadget: fix gadget endpoint selection 2020-05-14 12:30:17 +03:00
udc usb: gadget: tegra-xudc: Fix idle suspend/resume 2020-05-09 11:05:08 +03:00
composite.c usb: gadget: composite: Inform controller driver of self-powered 2020-03-15 12:10:14 +02:00
config.c
configfs.c usb: gadget: configfs: Add max_speed setting 2020-01-15 10:39:21 +01:00
configfs.h
epautoconf.c usb: gadget: move non-super speed code out of usb_ep_autoconfig_ss() 2019-02-07 13:14:51 +02:00
functions.c
Kconfig usb: gadget: move choice ... endchoice to legacy/Kconfig 2019-12-17 16:24:13 +01:00
Makefile Revert "usb:gadget Separated decoding functions from dwc3 driver." 2019-07-04 13:02:09 +02:00
u_f.c usb: gadget: Change Andrzej Pietrasiewicz's e-mail address 2019-02-11 11:12:29 +02:00
u_f.h usb: gadget: Change Andrzej Pietrasiewicz's e-mail address 2019-02-11 11:12:29 +02:00
u_os_desc.h usb: gadget: Change Andrzej Pietrasiewicz's e-mail address 2019-02-11 11:12:29 +02:00
usbstring.c usb/gadget: Constify usb_gadget_get_string "table" argument 2018-05-15 10:06:49 +03:00