From: Greg KH <gregkh@linuxfoundation.org>
To: Russ Weight <russell.h.weight@intel.com>
Cc: Tianfei Zhang <tianfei.zhang@intel.com>,
bhelgaas@google.com, linux-pci@vger.kernel.org,
linux-fpga@vger.kernel.org, lukas@wunner.de, kabel@kernel.org,
mani@kernel.org, pali@kernel.org, mdf@kernel.org,
hao.wu@intel.com, yilun.xu@intel.com, trix@redhat.com,
jgg@ziepe.ca, ira.weiny@intel.com,
andriy.shevchenko@linux.intel.com, dan.j.williams@intel.com,
keescook@chromium.org, rafael@kernel.org, corbet@lwn.net,
linux-doc@vger.kernel.org, ilpo.jarvinen@linux.intel.com,
lee@kernel.org, matthew.gerlach@linux.intel.com
Subject: Re: [PATCH v1 10/12] PCI: hotplug: implement the hotplug_slot_ops callback for fpgahp
Date: Sat, 21 Jan 2023 08:35:17 +0100 [thread overview]
Message-ID: <Y8uVtSw1qXhfHrNk@kroah.com> (raw)
In-Reply-To: <ea85cb02-a13d-f232-8ebd-c13893fc00c4@intel.com>
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@intel.com>
> >> ---
> >> 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@intel.com>
> >> +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@intel.com>
> >> +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
next prev parent reply other threads:[~2023-01-21 7:37 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-19 1:35 [PATCH v1 00/12] add FPGA hotplug manager driver Tianfei Zhang
2023-01-19 1:35 ` [PATCH v1 01/12] PCI: hotplug: add new callbacks on hotplug_slot_ops Tianfei Zhang
2023-01-19 13:31 ` Greg KH
2023-01-19 1:35 ` [PATCH v1 02/12] PCI: hotplug: expose APIs from pciehp driver Tianfei Zhang
2023-01-19 1:35 ` [PATCH v1 03/12] PCI: hotplug: add and expose link disable API Tianfei Zhang
2023-01-19 1:35 ` [PATCH v1 04/12] PCI: hotplug: add FPGA PCI hotplug manager driver Tianfei Zhang
2023-01-19 1:35 ` [PATCH v1 05/12] fpga: dfl: register dfl-pci device into fpgahph driver Tianfei Zhang
2023-01-19 1:35 ` [PATCH v1 06/12] driver core: expose device_is_ancestor() API Tianfei Zhang
2023-01-19 1:35 ` [PATCH v1 07/12] PCI: hotplug: add register/unregister function for BMC device Tianfei Zhang
2023-01-19 1:35 ` [PATCH v1 08/12] fpga: m10bmc-sec: register BMC device into fpgahp driver Tianfei Zhang
2023-01-19 1:35 ` [PATCH v1 09/12] fpga: dfl: remove non-reserved devices Tianfei Zhang
2023-01-19 1:36 ` [PATCH v1 10/12] PCI: hotplug: implement the hotplug_slot_ops callback for fpgahp Tianfei Zhang
2023-01-19 13:28 ` Greg KH
2023-01-20 22:38 ` Russ Weight
2023-01-21 7:35 ` Greg KH [this message]
2023-01-19 1:36 ` [PATCH v1 11/12] fpga: m10bmc-sec: add m10bmc_sec_retimer_load callback Tianfei Zhang
2023-01-19 14:22 ` Lee Jones
2023-01-19 1:36 ` [PATCH v1 12/12] Documentation: fpga: add description of fpgahp driver Tianfei Zhang
2023-01-19 9:38 ` Bagas Sanjaya
2023-01-19 8:06 ` [PATCH v1 00/12] add FPGA hotplug manager driver Pali Rohár
2023-01-19 8:17 ` Zhang, Tianfei
2023-01-19 11:27 ` andriy.shevchenko
2023-01-19 12:09 ` Zhang, Tianfei
2023-01-19 13:33 ` Greg KH
2023-01-19 13:43 ` Rafael J. Wysocki
2023-01-19 15:33 ` Greg KH
2023-01-20 16:28 ` Russ Weight
2023-01-20 18:42 ` Lukas Wunner
2023-01-21 7:34 ` Greg KH
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