| Message ID | 20210608054857.18963-1-ameynarkhede03@gmail.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | Expose and manage PCI device reset | expand |
On 08.06.21 07:48, Amey Narkhede wrote: Hi, > PCI and PCIe devices may support a number of possible reset mechanisms > for example Function Level Reset (FLR) provided via Advanced Feature or > PCIe capabilities, Power Management reset, bus reset, or device specific reset. > Currently the PCI subsystem creates a policy prioritizing these reset methods > which provides neither visibility nor control to userspace. Since I've got a current use case for that - could you perhaps tell more about the whole pci device reset mechanisms ? In my case I've got a board that wires reset lines to the soc's gpios. Not sure how exactly to qualify this, but I guess it would count as a bus wide reset. Now the big question for me is how to implement that in a board specific platform driver (which already does setup of gpios and other attached devices), so we can reset the card in slot X in a generic way. Any help highly appreciated. --mtx
On 21/06/08 12:05PM, Enrico Weigelt, metux IT consult wrote: > On 08.06.21 07:48, Amey Narkhede wrote: > > Hi, > > > PCI and PCIe devices may support a number of possible reset mechanisms > > for example Function Level Reset (FLR) provided via Advanced Feature or > > PCIe capabilities, Power Management reset, bus reset, or device specific reset. > > Currently the PCI subsystem creates a policy prioritizing these reset methods > > which provides neither visibility nor control to userspace. > > Since I've got a current use case for that - could you perhaps tell more > about the whole pci device reset mechanisms ? > > In my case I've got a board that wires reset lines to the soc's gpios. > Not sure how exactly to qualify this, but I guess it would count as a > bus wide reset. > > Now the big question for me is how to implement that in a board specific > platform driver (which already does setup of gpios and other attached > devices), so we can reset the card in slot X in a generic way. > > Any help highly appreciated. > > > --mtx > In case of bus reset(pci_reset_secondary_bus()), it uses bridge control register to assert reset on bus so I think it should out of the box but not 100% sure about it. Thanks, Amey
PCI and PCIe devices may support a number of possible reset mechanisms for example Function Level Reset (FLR) provided via Advanced Feature or PCIe capabilities, Power Management reset, bus reset, or device specific reset. Currently the PCI subsystem creates a policy prioritizing these reset methods which provides neither visibility nor control to userspace. Expose the reset methods available per device to userspace, via sysfs and allow an administrative user or device owner to have ability to manage per device reset method priorities or exclusions. This feature aims to allow greater control of a device for use cases as device assignment, where specific device or platform issues may interact poorly with a given reset method, and for which device specific quirks have not been developed. Changes in v7: - Fix the pci_dev_acpi_reset() prototype mismatch in case of CONFIG_ACPI=n Changes in v6: - Address Bjorn's and Krzysztof's review comments - Add Shanker's updated patches along with new "PCI: Setup ACPI_COMPANION early" patch Changes in v5: - Rebase the series over pci/reset branch of Bjorn's pci tree to avoid merge conflicts caused by recent changes in existing reset sysfs attribute Changes in v4: - Change the order or strlen and strim in reset_method_store function to avoid extra strlen call. - Use consistent terminology in new pci_reset_mode enum and rename the probe argument of reset functions. Changes in v3: - Dropped "PCI: merge slot and bus reset implementations" which was already accepted separately - Grammar fixes - Added Shanker's patches which were rebased on v2 of this series - Added "PCI: Change the type of probe argument in reset functions" and additional user input sanitization code in reset_method_store function per review feedback from Krzysztof Changes in v2: - Use byte array instead of bitmap to keep track of ordering of reset methods - Fix incorrect use of reset_fn field in octeon driver - Allow writing comma separated list of names of supported reset methods to reset_method sysfs attribute - Writing empty string instead of "none" to reset_method attribute disables ability of reset the device Amey Narkhede (5): PCI: Add pcie_reset_flr to follow calling convention of other reset methods PCI: Add new array for keeping track of ordering of reset methods PCI: Remove reset_fn field from pci_dev PCI/sysfs: Allow userspace to query and set device reset mechanism PCI: Change the type of probe argument in reset functions Shanker Donthineni (3): PCI: Setup ACPI_COMPANION early PCI: Add support for ACPI _RST reset method PCI: Enable NO_BUS_RESET quirk for Nvidia GPUs Documentation/ABI/testing/sysfs-bus-pci | 16 ++ drivers/crypto/cavium/nitrox/nitrox_main.c | 4 +- .../ethernet/cavium/liquidio/lio_vf_main.c | 2 +- drivers/pci/hotplug/pciehp.h | 2 +- drivers/pci/hotplug/pciehp_hpc.c | 4 +- drivers/pci/pci-acpi.c | 39 ++- drivers/pci/pci-sysfs.c | 120 ++++++++- drivers/pci/pci.c | 238 +++++++++++------- drivers/pci/pci.h | 22 +- drivers/pci/pcie/aer.c | 12 +- drivers/pci/probe.c | 6 +- drivers/pci/quirks.c | 54 ++-- drivers/pci/remove.c | 1 - include/linux/pci.h | 16 +- include/linux/pci_hotplug.h | 2 +- 15 files changed, 393 insertions(+), 145 deletions(-) -- 2.31.1