From 97730bbb242cde22b7140acd202ffd88823886c9 Mon Sep 17 00:00:00 2001 From: Russ Weight Date: Thu, 21 Apr 2022 14:22:00 -0700 Subject: firmware_loader: Add firmware-upload support Extend the firmware subsystem to support a persistent sysfs interface that userspace may use to initiate a firmware update. For example, FPGA based PCIe cards load firmware and FPGA images from local FLASH when the card boots. The images in FLASH may be updated with new images provided by the user at his/her convenience. A device driver may call firmware_upload_register() to expose persistent "loading" and "data" sysfs files. These files are used in the same way as the fallback sysfs "loading" and "data" files. When 0 is written to "loading" to complete the write of firmware data, the data is transferred to the lower-level driver using pre-registered call-back functions. The data transfer is done in the context of a kernel worker thread. Reviewed-by: Luis Chamberlain Reviewed-by: Tianfei zhang Tested-by: Matthew Gerlach Signed-off-by: Russ Weight Link: https://lore.kernel.org/r/20220421212204.36052-5-russell.h.weight@intel.com Signed-off-by: Greg Kroah-Hartman --- Documentation/ABI/testing/sysfs-class-firmware | 32 ++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-class-firmware (limited to 'Documentation/ABI') diff --git a/Documentation/ABI/testing/sysfs-class-firmware b/Documentation/ABI/testing/sysfs-class-firmware new file mode 100644 index 000000000000..18336c23b70d --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-firmware @@ -0,0 +1,32 @@ +What: /sys/class/firmware/.../data +Date: July 2022 +KernelVersion: 5.19 +Contact: Russ Weight +Description: The data sysfs file is used for firmware-fallback and for + firmware uploads. Cat a firmware image to this sysfs file + after you echo 1 to the loading sysfs file. When the firmware + image write is complete, echo 0 to the loading sysfs file. This + sequence will signal the completion of the firmware write and + signal the lower-level driver that the firmware data is + available. + +What: /sys/class/firmware/.../loading +Date: July 2022 +KernelVersion: 5.19 +Contact: Russ Weight +Description: The loading sysfs file is used for both firmware-fallback and + for firmware uploads. Echo 1 onto the loading file to indicate + you are writing a firmware file to the data sysfs node. Echo + -1 onto this file to abort the data write or echo 0 onto this + file to indicate that the write is complete. For firmware + uploads, the zero value also triggers the transfer of the + firmware data to the lower-level device driver. + +What: /sys/class/firmware/.../timeout +Date: July 2022 +KernelVersion: 5.19 +Contact: Russ Weight +Description: This file supports the timeout mechanism for firmware + fallback. This file has no affect on firmware uploads. For + more information on timeouts please see the documentation + for firmware fallback. -- cgit v1.2.3-70-g09d2