On Fri, Jan 20, 2023 at 02:38:43PM -0800, Russ Weight wrote: > > > On 1/19/23 05:28, Greg KH wrote: > > On Wed, Jan 18, 2023 at 08:36:00PM -0500, Tianfei Zhang wrote: > >> Implement the image_load and available_images callback functions > >> for fpgahp driver. This patch leverages some APIs from pciehp > >> driver to implement the device reconfiguration below the PCI hotplug > >> bridge. > >> > >> Here are the steps for a process of image load. > >> 1. remove all PFs and VFs except the PF0. > >> 2. remove all non-reserved devices of PF0. > >> 3. trigger a image load via BMC. > >> 4. disable the link of the hotplug bridge. > >> 5. remove all reserved devices under PF0 and PCI devices > >> below the hotplug bridge. > >> 6. wait for image load done via BMC, e.g. 10s. > >> 7. re-enable the link of the hotplug bridge. > >> 8. re-enumerate PCI devices below the hotplug bridge. > >> > >> Signed-off-by: Tianfei Zhang <tianfei.zhang@xxxxxxxxx> > >> --- > >> Documentation/ABI/testing/sysfs-driver-fpgahp | 21 ++ > >> MAINTAINERS | 1 + > >> drivers/pci/hotplug/fpgahp.c | 179 ++++++++++++++++++ > >> 3 files changed, 201 insertions(+) > >> create mode 100644 Documentation/ABI/testing/sysfs-driver-fpgahp > >> > >> diff --git a/Documentation/ABI/testing/sysfs-driver-fpgahp b/Documentation/ABI/testing/sysfs-driver-fpgahp > >> new file mode 100644 > >> index 000000000000..8d4b1bfc4012 > >> --- /dev/null > >> +++ b/Documentation/ABI/testing/sysfs-driver-fpgahp > >> @@ -0,0 +1,21 @@ > >> +What: /sys/bus/pci/slots/X-X/available_images > >> +Date: May 2023 > >> +KernelVersion: 6.3 > >> +Contact: Tianfei Zhang <tianfei.zhang@xxxxxxxxx> > >> +Description: Read-only. This file returns a space separated list of > >> + key words that may be written into the image_load file > >> + described below. These keywords decribe an FPGA, BMC, > >> + or firmware image in FLASH or EEPROM storage that may > >> + be loaded. > > No, sysfs is "one value per file", why is this a list? > > > > And what exactly defines the values in this list? > > > >> + > >> +What: /sys/bus/pci/slots/X-X/image_load > >> +Date: May 2023 > >> +KernelVersion: 6.3 > >> +Contact: Tianfei Zhang <tianfei.zhang@xxxxxxxxx> > >> +Description: Write-only. A key word may be written to this file to > >> + trigger a new image loading of an FPGA, BMC, or firmware > >> + image from FLASH or EEPROM. Refer to the available_images > >> + file for a list of supported key words for the underlying > >> + device. > >> + Writing an unsupported string to this file will result in > >> + EINVAL being returned. > > Why is this a separate file from the "read the list" file? > > The intended usage is like this: > > $ cat available_images > bmc_factory bmc_user fpga_factory fpga_user1 fpga_user2 > $ echo bmc_user > image_load > > This specifies which image stored in flash that you want to have activated > on the device. > > An existing example of something like this is in the tracing code: > available_tracers and current_tracer > > Would it be preferable to just create a file for each possible image, > and echo 1 to trigger the event? (echo 1 > bmc_user) That would make things much more simpler overall and not force people to have to parse a sysfs file, which is the main reason we created sysfs in the first place. thanks, greg k-h
