[PATCH v4 2/5] PCI/ERR: Add support for resetting the slots in a platform specific way
Krishna Chaitanya Chundru
krishna.chundru at oss.qualcomm.com
Wed May 14 16:33:16 AEST 2025
On 5/8/2025 12:40 PM, Manivannan Sadhasivam wrote:
> Some host bridge devices require resetting the slots in a platform specific
> way to recover them from error conditions such as Fatal AER errors, Link
> Down etc... So introduce pci_host_bridge::reset_slot callback and call it
> from pcibios_reset_secondary_bus() if available.
>
> The 'reset_slot' callback is responsible for resetting the given slot
> referenced by the 'pci_dev' pointer in a platform specific way and bring it
> back to the working state if possible. If any error occurs during the slot
> reset operation, relevant errno should be returned.
>
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam at linaro.org>
Reviewed-by: Krishna Chaitanya Chundru <krishna.chundru at oss.qualcomm.com>
- Krishna Chaitanya.
> ---
> drivers/pci/pci.c | 12 ++++++++++++
> drivers/pci/pcie/err.c | 5 -----
> include/linux/pci.h | 1 +
> 3 files changed, 13 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 4d7c9f64ea24ec754a135a2585c99489cfa641a9..13709bb898a967968540826a2b7ee8ade6b7e082 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -4982,7 +4982,19 @@ void pci_reset_secondary_bus(struct pci_dev *dev)
>
> void __weak pcibios_reset_secondary_bus(struct pci_dev *dev)
> {
> + struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
> + int ret;
> +
> + if (host->reset_slot) {
> + ret = host->reset_slot(host, dev);
> + if (ret)
> + pci_err(dev, "failed to reset slot: %d\n", ret);
> +
> + return;
> + }
> +
> pci_reset_secondary_bus(dev);
> +
> }
>
> /**
> diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
> index de6381c690f5c21f00021cdc7bde8d93a5c7db52..b834fc0d705938540d3d7d3d8739770c09fe7cf1 100644
> --- a/drivers/pci/pcie/err.c
> +++ b/drivers/pci/pcie/err.c
> @@ -234,11 +234,6 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
> }
>
> if (status == PCI_ERS_RESULT_NEED_RESET) {
> - /*
> - * TODO: Should call platform-specific
> - * functions to reset slot before calling
> - * drivers' slot_reset callbacks?
> - */
> status = PCI_ERS_RESULT_RECOVERED;
> pci_dbg(bridge, "broadcast slot_reset message\n");
> pci_walk_bridge(bridge, report_slot_reset, &status);
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 0e8e3fd77e96713054388bdc82f439e51023c1bf..8d7d2a49b76cf64b4218b179cec495e0d69ddf6f 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -599,6 +599,7 @@ struct pci_host_bridge {
> void (*release_fn)(struct pci_host_bridge *);
> int (*enable_device)(struct pci_host_bridge *bridge, struct pci_dev *dev);
> void (*disable_device)(struct pci_host_bridge *bridge, struct pci_dev *dev);
> + int (*reset_slot)(struct pci_host_bridge *bridge, struct pci_dev *dev);
> void *release_data;
> unsigned int ignore_reset_delay:1; /* For entire hierarchy */
> unsigned int no_ext_tags:1; /* No Extended Tags */
>
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