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2024-08-13usb: gadget: f_fs: add capability for dfu functional descriptorDavid Sands
Add the ability for the USB FunctionFS (FFS) gadget driver to be able to create Device Firmware Upgrade (DFU) functional descriptors. [1] This patch allows implementation of DFU in userspace using the FFS gadget. The DFU protocol uses the control pipe (ep0) for all messaging so only the addition of the DFU functional descriptor is needed in the kernel driver. The DFU functional descriptor is written to the ep0 file along with any other descriptors during FFS setup. DFU requires an interface descriptor followed by the DFU functional descriptor. This patch includes documentation of the added descriptor for DFU and conversion of some existing documentation to kernel-doc format so that it can be included in the generated docs. An implementation of DFU 1.1 that implements just the runtime descriptor using the FunctionFS gadget (with rebooting into u-boot for DFU mode) has been tested on an i.MX8 Nano. An implementation of DFU 1.1 that implements both runtime and DFU mode using the FunctionFS gadget has been tested on Xilinx Zynq UltraScale+. Note that for the best performance of firmware update file transfers, the userspace program should respond as quick as possible to the setup packets. [1] https://www.usb.org/sites/default/files/DFU_1.1.pdf Signed-off-by: David Sands <david.sands@biamp.com> Co-developed-by: Chris Wulff <crwulff@gmail.com> Signed-off-by: Chris Wulff <crwulff@gmail.com> Link: https://lore.kernel.org/r/20240811000004.1395888-2-crwulff@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-09docs: usb: Add documentation for the UVC GadgetDaniel Scally
The UVC Gadget function has become quite complex, but documentation for it is fairly sparse. Add some more detailed documentation to improve the situation. Signed-off-by: Daniel Scally <dan.scally@ideasonboard.com> Link: https://lore.kernel.org/r/20230308165213.139315-1-dan.scally@ideasonboard.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-15usb: gadget: add raw-gadget interfaceAndrey Konovalov
USB Raw Gadget is a kernel module that provides a userspace interface for the USB Gadget subsystem. Essentially it allows to emulate USB devices from userspace. Enabled with CONFIG_USB_RAW_GADGET. Raw Gadget is currently a strictly debugging feature and shouldn't be used in production. Raw Gadget is similar to GadgetFS, but provides a more low-level and direct access to the USB Gadget layer for the userspace. The key differences are: 1. Every USB request is passed to the userspace to get a response, while GadgetFS responds to some USB requests internally based on the provided descriptors. However note, that the UDC driver might respond to some requests on its own and never forward them to the Gadget layer. 2. GadgetFS performs some sanity checks on the provided USB descriptors, while Raw Gadget allows you to provide arbitrary data as responses to USB requests. 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). 5. Raw Gadget has ioctl-based interface instead of a filesystem-based one. Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Signed-off-by: Felipe Balbi <balbi@kernel.org>
2020-01-28docs: usb: remove some broken referencesMauro Carvalho Chehab
It seems that some files were removed from USB documentation. Update the links accordingly. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/00008303fde6b4e06d027d3b76ae7032614a7030.1580193653.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2019-06-20docs: usb: rename files to .rst and add them to drivers-apiMauro Carvalho Chehab
While there are a mix of things here, most of the stuff were written from Kernel developer's PoV. So, add them to the driver-api book. A follow up for this patch would be to move documents from there that are specific to sysadmins, adding them to the admin-guide. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Acked-by: Johan Hovold <johan@kernel.org> Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>