On 2026-08-21 18:04:01 Fri, Avinash Roy wrote:
> From: Shivaprasad G Bhat <[email protected]>
>
> The IBM Spyre accelerator (PCI ID 1014:06a7) requires a dedicated warm
> reset method for reliable EEH recovery on pSeries/ppc64 platforms.
>
> FLR alone is insufficient because it does not re-initialize firmware
> state machine for the current version of the card. The existing API
> pci_set_pcie_reset_state() is used to drive the platform-level
> PERST# using the EEH interfaces by adding a device specific quirk.
>
> The reset function is placed in arch/powerpc/platforms/pseries/pci.c
> where the EEH infrastructure is already present, declared in
> pseries.h, and registered in the generic pci_dev_reset_methods[] table
> in drivers/pci/quirks.c under a CONFIG_PPC_PSERIES guard.
>
> This reset method is only registered when CONFIG_PPC_PSERIES is enabled,
> so it is not available on other platforms.
>
> Reset sequence:
> - Assert PERST# via pcie_warm_reset, hold 250 ms
> - Deassert PERST# via pcie_deassert_reset
> - Wait 250 ms for PCIe link retrain
>
> Signed-off-by: Avinash Roy <[email protected]>
> Signed-off-by: Shivaprasad G Bhat <[email protected]>
>
> ---
> Changelog
> v1:
> https://lore.kernel.org/linux-pci/[email protected]/
>
> Reworded the commit message to highlight the warm reset requirement being
> a need of the current card and not a platform deficiency.
>
> diff --git a/arch/powerpc/platforms/pseries/pci.c
> b/arch/powerpc/platforms/pseries/pci.c
> index 84e4ffe957a8..7aa58d57208f 100644
> --- a/arch/powerpc/platforms/pseries/pci.c
> +++ b/arch/powerpc/platforms/pseries/pci.c
> @@ -11,6 +11,7 @@
> #include <linux/kernel.h>
> #include <linux/pci.h>
> #include <linux/string.h>
> +#include <linux/delay.h>
>
> #include <asm/eeh.h>
> #include <asm/pci-bridge.h>
> @@ -236,6 +237,41 @@ static void fixup_winbond_82c105(struct pci_dev* dev)
> DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_WINBOND, PCI_DEVICE_ID_WINBOND_82C105,
> fixup_winbond_82c105);
>
> +/*
> + * Reset Spyre adapter using pci_set_pcie_reset_state()
> + * This is specifically for PPC platforms where EEH (Enhanced Error Handling)
> + * requires this reset method for proper device recovery.
> + */
> +int reset_spyre(struct pci_dev *dev, bool probe)
> +{
> + int ret;
> +
> + if (probe)
> + return 0;
> +
> + /* Assert warm reset */
> + ret = pci_set_pcie_reset_state(dev, pcie_warm_reset);
> + if (ret) {
> + pci_err(dev, "Failed to assert reset: %d\n", ret);
> + return ret;
> + }
> +
> + /* Wait for reset to take effect */
> + msleep(250);
How did you arriver on this number ? Is this time defined by
hardware/firmware specs for reset ? Also, Can you #define the value 250
and use macro instead of constant numbmer.
> +
> + /* Deassert reset */
> + ret = pci_set_pcie_reset_state(dev, pcie_deassert_reset);
> + if (ret) {
> + pci_err(dev, "Failed to deassert reset: %d\n", ret);
> + return ret;
> + }
> +
> + /* Wait for device to recover */
> + msleep(250);
same here.
> +
> + return 0;
> +}
> +
Thanks,
-Mahesh.
