PCI/DPC: Expose dpc_process_error(), dpc_reset_link() for use by EDR

If firmware controls DPC, it is generally responsible for managing the DPC
capability and events, and the OS should not access the DPC capability.

However, if firmware controls DPC and both the OS and the platform support
Error Disconnect Recover (EDR) notifications, the OS EDR notify handler is
responsible for recovery, and the notify handler may read/write the DPC
capability until it clears the DPC Trigger Status bit.  See [1], sec 4.5.1,
table 4-6.

Expose some DPC error handling functions so they can be used by the EDR
notify handler.

[1] Downstream Port Containment Related Enhancements ECN, Jan 28, 2019,
    affecting PCI Firmware Specification, Rev. 3.2
    https://members.pcisig.com/wg/PCI-SIG/document/12888

Link: https://lore.kernel.org/r/e9000bb15b3a4293e81d98bb29ead7c84a6393c9.1585000084.git.sathyanarayanan.kuppuswamy@linux.intel.com
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 6d09bb22b73d5018a52bb06f0076e7ae8b0cff6f..25265bf80a83f292cb90a767e66da4d635c41a13 100644 (file)
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -449,6 +449,8 @@ void aer_print_error(struct pci_dev *dev, struct aer_err_info *info);
 void pci_save_dpc_state(struct pci_dev *dev);
 void pci_restore_dpc_state(struct pci_dev *dev);
 void pci_dpc_init(struct pci_dev *pdev);
+void dpc_process_error(struct pci_dev *pdev);
+pci_ers_result_t dpc_reset_link(struct pci_dev *pdev);
 #else
 static inline void pci_save_dpc_state(struct pci_dev *dev) {}
 static inline void pci_restore_dpc_state(struct pci_dev *dev) {}

diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
index a1c9d45876bdf82b77a779f44f30456e50662ddd..22998ee2f7ea1c7bd367f170712304d88f8489dc 100644 (file)
--- a/drivers/pci/pcie/dpc.c
+++ b/drivers/pci/pcie/dpc.c
@@ -89,7 +89,7 @@ static int dpc_wait_rp_inactive(struct pci_dev *pdev)
        return 0;
 }
 
-static pci_ers_result_t dpc_reset_link(struct pci_dev *pdev)
+pci_ers_result_t dpc_reset_link(struct pci_dev *pdev)
 {
        u16 cap;
 
@@ -193,9 +193,8 @@ static int dpc_get_aer_uncorrect_severity(struct pci_dev *dev,
        return 1;
 }
 
-static irqreturn_t dpc_handler(int irq, void *context)
+void dpc_process_error(struct pci_dev *pdev)
 {
-       struct pci_dev *pdev = context;
        u16 cap = pdev->dpc_cap, status, source, reason, ext_reason;
        struct aer_err_info info;
 
@@ -225,6 +224,13 @@ static irqreturn_t dpc_handler(int irq, void *context)
                pci_cleanup_aer_uncorrect_error_status(pdev);
                pci_aer_clear_fatal_status(pdev);
        }
+}
+
+static irqreturn_t dpc_handler(int irq, void *context)
+{
+       struct pci_dev *pdev = context;
+
+       dpc_process_error(pdev);
 
        /* We configure DPC so it only triggers on ERR_FATAL */
        pcie_do_recovery(pdev, pci_channel_io_frozen, dpc_reset_link);