Re: [RFC PATCH 0/5] Firmware Upload Framework

[Bjorn Andersson <bjorn.andersson@linaro.org>]

On Mon 15 Nov 05:57 PST 2021, Tom Rix wrote:

> 
> On 11/10/21 5:13 PM, Russ Weight wrote:
> > The Firmware Upload framework provides a common API for uploading firmware
> > files to target devices. An example use case involves FPGA devices that
> > load FPGA, Card BMC, and firmware images from FLASH when the card boots.
> > Users need the ability to update these firmware images while the card is
> > in use.
> > 
> > Device drivers that instantiate the Firmware Upload class driver will
> > interact with the target device to transfer and authenticate the firmware
> > data. Uploads are performed in the context of a kernel worker thread in
> > order to facilitate progress indicators during lengthy uploads.
> > 
> > This driver was previously submitted in the context of the FPGA sub-
> > system as the "FPGA Image Load Framework", but the framework is generic
> > enough to support other devices as well. The previous submission of this
> > patch-set can be viewed here:
> > 
> > https://marc.info/?l=linux-kernel&m=163295640216820&w=2
> > 
> > The n3000bmc-sec-update driver is the first driver to use the Firmware
> > Upload API. A recent version of these patches can be viewed here:
> > 
> > https://marc.info/?l=linux-kernel&m=163295697217095&w=2
> > 
> > I don't think I am duplicating any functionality that is currently covered
> > in the firmware subsystem. I appreciate your feedback on these patches.
> 
> This may be a common api for fpga/dfl-, but it is not likely common for
> general devices.
> 

During my years of hacking on device drivers I've run into the need for
being able to reflash/update firmware in things such as touchscreen
controllers, hdmi bridges, usb network devices and (embedded) usb hubs.

The implementation typically manifest itself as some sysfs or debugfs
knob which when written triggers a request_firmware() followed by the
operation to write the content to flash. But the result is often quite
hacky and requires that you store the firmware-to-be-written in some
path that will be looked at by request_firmware() - and hence these
patches often doesn't end up upstream.

So I'm certainly in favor of some generic way for drivers to expose an
interface for userspace to flash new firmware to their associated
hardware.

Regards,
Bjorn

> Could the scope of this patchset be reduced to just fpga/dfl for now ?
> 
> Something more like stratix10-rsu.
> 
> Tom
> 
> > 
> > - Russ
> > 
> > Russ Weight (5):
> >    firmware: Create firmware upload framework
> >    firmware: upload: Enable firmware uploads
> >    firmware: upload: Signal eventfd when complete
> >    firmware: upload: Add status ioctl
> >    firmware: upload: Enable cancel of firmware upload
> > 
> >   .../driver-api/firmware/firmware-upload.rst   |  54 +++
> >   Documentation/driver-api/firmware/index.rst   |   1 +
> >   MAINTAINERS                                   |   9 +
> >   drivers/firmware/Kconfig                      |   8 +
> >   drivers/firmware/Makefile                     |   1 +
> >   drivers/firmware/firmware-upload.c            | 413 ++++++++++++++++++
> >   include/linux/firmware/firmware-upload.h      |  69 +++
> >   include/uapi/linux/firmware-upload.h          |  73 ++++
> >   8 files changed, 628 insertions(+)
> >   create mode 100644 Documentation/driver-api/firmware/firmware-upload.rst
> >   create mode 100644 drivers/firmware/firmware-upload.c
> >   create mode 100644 include/linux/firmware/firmware-upload.h
> >   create mode 100644 include/uapi/linux/firmware-upload.h
> > 
>