[PATCH v6 1/4] PCI/ERR: Add support for resetting the Root Ports in a platform specific way
From: Manivannan Sadhasivam via B4 Relay <devnull+manivannan.sadhasivam.oss.qualcomm.com@kernel.org>
Date: 2025-07-15 14:21:11
Also in:
b4-sent, linux-arm-kernel, linux-arm-msm, linux-pci, linux-rockchip, lkml
Subsystem:
pci enhanced error handling (eeh) for powerpc, pci subsystem, the rest · Maintainers:
Mahesh J Salgaonkar, Bjorn Helgaas, Linus Torvalds
From: Manivannan Sadhasivam <mani@kernel.org> Some host bridge devices require resetting the Root Ports 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_root_port() callback and call it from pcibios_reset_secondary_bus() if available. Also, save the Root Port config space before reset and restore it afterwards. The 'reset_root_port' callback is responsible for resetting the given Root Port 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 reset operation, relevant errno should be returned. Signed-off-by: Manivannan Sadhasivam <redacted> Signed-off-by: Manivannan Sadhasivam <redacted> --- drivers/pci/pci.c | 20 ++++++++++++++++++++ drivers/pci/pcie/err.c | 5 ----- include/linux/pci.h | 1 + 3 files changed, 21 insertions(+), 5 deletions(-)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index e9448d55113bdfd2263d8e2f6b3ec802f56b712e..b29264aa2be33b18a58b3b3db1d1fb0f6483e5e8 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c@@ -4964,6 +4964,26 @@ 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 (pci_is_root_bus(dev->bus) && host->reset_root_port) { + /* + * Save the config space of the Root Port before doing the + * reset, since the state could be lost. The Endpoint state + * should've been saved by the caller. + */ + pci_save_state(dev); + ret = host->reset_root_port(host, dev); + if (ret) + pci_err(dev, "Failed to reset Root Port: %d\n", ret); + else + /* Now restore it on success */ + pci_restore_state(dev); + + 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 05e68f35f39238f8b9ce08df97b384d1c1e89bbe..e7c118a961910a307ec365f17b8fe4f2585267e8 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_root_port)(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 */
--
2.45.2