DPC is only for error recovery. Since we're not removing the topology
and relying on link state interrupts to re-enumerate anymore, the dpc
reset handler has to implement the required reset timings and checks.
Signed-off-by: Keith Busch <keith.busch@xxxxxxxxx>
---
drivers/pci/pcie/dpc.c | 32 +++++++++++++++++++-------------
1 file changed, 19 insertions(+), 13 deletions(-)
diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
index 93ce26191a2b..34bac3e2beac 100644
--- a/drivers/pci/pcie/dpc.c
+++ b/drivers/pci/pcie/dpc.c
@@ -66,32 +66,38 @@ static int dpc_wait_rp_inactive(struct dpc_dev *dpc)
static pci_ers_result_t dpc_reset_link(struct pci_dev *pdev)
{
- struct dpc_dev *dpc;
- struct pcie_device *pciedev;
- struct device *devdpc;
-
- u16 cap;
+ struct device *dev = pcie_port_find_device(pdev, PCIE_PORT_SERVICE_DPC);
+ struct pcie_device *pciedev = to_pcie_device(dev);
+ struct dpc_dev *dpc = get_service_data(pciedev);
+ u16 cap = dpc->cap_pos;
/*
* DPC disables the Link automatically in hardware, so it has
* already been reset by the time we get here.
- */
- devdpc = pcie_port_find_device(pdev, PCIE_PORT_SERVICE_DPC);
- pciedev = to_pcie_device(devdpc);
- dpc = get_service_data(pciedev);
- cap = dpc->cap_pos;
-
- /*
+ *
* Wait until the Link is inactive, then clear DPC Trigger Status
* to allow the Port to leave DPC.
*/
pcie_wait_for_link(pdev, false);
-
if (dpc->rp_extensions && dpc_wait_rp_inactive(dpc))
return PCI_ERS_RESULT_DISCONNECT;
pci_write_config_word(pdev, cap + PCI_EXP_DPC_STATUS,
PCI_EXP_DPC_STATUS_TRIGGER);
+ /*
+ * PCIe 4.0r1 6.6.1, a component must enter LTSSM Detect within 20ms,
+ * after which we should expect an link active if the reset was
+ * successful. If so, software must wait a minimum 100ms before sending
+ * configuration requests to devices downstream this port.
+ *
+ * If the link fails to activate, either the device was physically
+ * removed or the link is permanently failed.
+ */
+ msleep(20);
+ if (!pcie_wait_for_link(pdev, true))
+ return PCI_ERS_RESULT_DISCONNECT;
+ msleep(100);
+
if (pdev->subordinate)
pdev->subordinate->error_state = pci_channel_io_normal;
return PCI_ERS_RESULT_RECOVERED;
--
2.14.4
