diff options
Diffstat (limited to 'drivers/pci/pci.c')
| -rw-r--r-- | drivers/pci/pci.c | 41 |
1 files changed, 28 insertions, 13 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index e3a49f66982d..fc2ecb7fe081 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -1283,7 +1283,9 @@ static int pci_dev_wait(struct pci_dev *dev, char *reset_type, int timeout) { int delay = 1; bool retrain = false; - struct pci_dev *bridge; + struct pci_dev *root, *bridge; + + root = pcie_find_root_port(dev); if (pci_is_pcie(dev)) { bridge = pci_upstream_bridge(dev); @@ -1292,16 +1294,23 @@ static int pci_dev_wait(struct pci_dev *dev, char *reset_type, int timeout) } /* - * After reset, the device should not silently discard config - * requests, but it may still indicate that it needs more time by - * responding to them with CRS completions. The Root Port will - * generally synthesize ~0 (PCI_ERROR_RESPONSE) data to complete - * the read (except when CRS SV is enabled and the read was for the - * Vendor ID; in that case it synthesizes 0x0001 data). + * The caller has already waited long enough after a reset that the + * device should respond to config requests, but it may respond + * with Request Retry Status (RRS) if it needs more time to + * initialize. + * + * If the device is below a Root Port with Configuration RRS + * Software Visibility enabled, reading the Vendor ID returns a + * special data value if the device responded with RRS. Read the + * Vendor ID until we get non-RRS status. * - * Wait for the device to return a non-CRS completion. Read the - * Command register instead of Vendor ID so we don't have to - * contend with the CRS SV value. + * If there's no Root Port or Configuration RRS Software Visibility + * is not enabled, the device may still respond with RRS, but + * hardware may retry the config request. If no retries receive + * Successful Completion, hardware generally synthesizes ~0 + * (PCI_ERROR_RESPONSE) data to complete the read. Reading Vendor + * ID for VFs and non-existent devices also returns ~0, so read the + * Command register until it returns something other than ~0. */ for (;;) { u32 id; @@ -1311,9 +1320,15 @@ static int pci_dev_wait(struct pci_dev *dev, char *reset_type, int timeout) return -ENOTTY; } - pci_read_config_dword(dev, PCI_COMMAND, &id); - if (!PCI_POSSIBLE_ERROR(id)) - break; + if (root && root->config_crs_sv) { + pci_read_config_dword(dev, PCI_VENDOR_ID, &id); + if (!pci_bus_crs_vendor_id(id)) + break; + } else { + pci_read_config_dword(dev, PCI_COMMAND, &id); + if (!PCI_POSSIBLE_ERROR(id)) + break; + } if (delay > timeout) { pci_warn(dev, "not ready %dms after %s; giving up\n", |