From 97df5e5758f7d1dd0ca97e3210696818fc45bdb3 Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Thu, 7 May 2020 19:06:56 +0200 Subject: 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: f2c2e717642c ("usb: gadget: add raw-gadget interface") Signed-off-by: Andrey Konovalov Signed-off-by: Felipe Balbi --- Documentation/usb/raw-gadget.rst | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'Documentation') diff --git a/Documentation/usb/raw-gadget.rst b/Documentation/usb/raw-gadget.rst index 9e78cb858f86..4af8b1f15574 100644 --- a/Documentation/usb/raw-gadget.rst +++ b/Documentation/usb/raw-gadget.rst @@ -27,9 +27,8 @@ differences are: 3. Raw Gadget provides a way to select a UDC device/driver to bind to, while GadgetFS currently binds to the first available UDC. -4. Raw Gadget uses predictable endpoint names (handles) across different - UDCs (as long as UDCs have enough endpoints of each required transfer - type). +4. Raw Gadget explicitly exposes information about endpoints addresses and + capabilities allowing a user to write UDC-agnostic gadgets. 5. Raw Gadget has ioctl-based interface instead of a filesystem-based one. -- cgit v1.2.3 From c61769bd4777a922952aed0d042a2572e5bd9b74 Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Thu, 7 May 2020 19:06:57 +0200 Subject: usb: raw-gadget: support stalling/halting/wedging endpoints Raw Gadget is currently unable to stall/halt/wedge gadget endpoints, which is required for proper emulation of certain USB classes. This patch adds a few more ioctls: - USB_RAW_IOCTL_EP0_STALL allows to stall control endpoint #0 when there's a pending setup request for it. - USB_RAW_IOCTL_SET/CLEAR_HALT/WEDGE allow to set/clear halt/wedge status on non-control non-isochronous endpoints. Fixes: f2c2e717642c ("usb: gadget: add raw-gadget interface") Signed-off-by: Andrey Konovalov Signed-off-by: Felipe Balbi --- Documentation/usb/raw-gadget.rst | 2 -- 1 file changed, 2 deletions(-) (limited to 'Documentation') diff --git a/Documentation/usb/raw-gadget.rst b/Documentation/usb/raw-gadget.rst index 4af8b1f15574..3b3d78e850b2 100644 --- a/Documentation/usb/raw-gadget.rst +++ b/Documentation/usb/raw-gadget.rst @@ -52,8 +52,6 @@ The typical usage of Raw Gadget looks like: Potential future improvements ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -- Implement ioctl's for setting/clearing halt status on endpoints. - - Reporting more events (suspend, resume, etc.) through USB_RAW_IOCTL_EVENT_FETCH. -- cgit v1.2.3 From 61d2658db48af0c563d126cccc5c1105137b1ec9 Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Thu, 7 May 2020 19:06:58 +0200 Subject: usb: raw-gadget: documentation updates Mention the issue with fixed UDC addresses. Links external examples and test suite. Add more implmenetation details and potential improvements. Signed-off-by: Andrey Konovalov Signed-off-by: Felipe Balbi --- Documentation/usb/raw-gadget.rst | 30 ++++++++++++++++++++++++++++-- 1 file changed, 28 insertions(+), 2 deletions(-) (limited to 'Documentation') diff --git a/Documentation/usb/raw-gadget.rst b/Documentation/usb/raw-gadget.rst index 3b3d78e850b2..68d879a8009e 100644 --- a/Documentation/usb/raw-gadget.rst +++ b/Documentation/usb/raw-gadget.rst @@ -49,10 +49,36 @@ The typical usage of Raw Gadget looks like: Raw Gadget and react to those depending on what kind of USB device needs to be emulated. +Note, that some UDC drivers have fixed addresses assigned to endpoints, and +therefore arbitrary endpoint addresses can't be used in the descriptors. +Nevertheles, Raw Gadget provides a UDC-agnostic way to write USB gadgets. +Once a USB_RAW_EVENT_CONNECT event is received via USB_RAW_IOCTL_EVENT_FETCH, +the USB_RAW_IOCTL_EPS_INFO ioctl can be used to find out information about +endpoints that the UDC driver has. Based on that information, the user must +chose UDC endpoints that will be used for the gadget being emulated, and +properly assign addresses in endpoint descriptors. + +You can find usage examples (along with a test suite) here: + +https://github.com/xairy/raw-gadget + +Internal details +~~~~~~~~~~~~~~~~ + +Currently every endpoint read/write ioctl submits a USB request and waits until +its completion. This is the desired mode for coverage-guided fuzzing (as we'd +like all USB request processing happen during the lifetime of a syscall), +and must be kept in the implementation. (This might be slow for real world +applications, thus the O_NONBLOCK improvement suggestion below.) + Potential future improvements ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -- Reporting more events (suspend, resume, etc.) through - USB_RAW_IOCTL_EVENT_FETCH. +- Report more events (suspend, resume, etc.) through USB_RAW_IOCTL_EVENT_FETCH. - Support O_NONBLOCK I/O. + +- Support USB 3 features (accept SS endpoint companion descriptor when + enabling endpoints; allow providing stream_id for bulk transfers). + +- Support ISO transfer features (expose frame_number for completed requests). -- cgit v1.2.3