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Subject[PATCH v11 01/16] AER: aer_root_reset() non-native handling
Date
If an OS has not been granted AER control via _OSC, then
the OS should not make changes to PCI_ERR_ROOT_COMMAND and
PCI_ERR_ROOT_STATUS related registers. Per section 4.5.1 of
the System Firmware Intermediary (SFI) _OSC and DPC Updates
ECN [1], this bit also covers these aspects of the PCI
Express Advanced Error Reporting. Based on the above and
earlier discussion [2], make the following changes:

Add a check for the native case (i.e., AER control via _OSC)

Note that the current "clear, reset, enable" order suggests that the
reset might cause errors that we should ignore. Lacking historical
context, these will be retained.

[1] System Firmware Intermediary (SFI) _OSC and DPC Updates ECN, Feb 24,
2020, affecting PCI Firmware Specification, Rev. 3.2
https://members.pcisig.com/wg/PCI-SIG/document/14076
[2] https://lore.kernel.org/linux-pci/20201020162820.GA370938@bjorn-Precision-5520/

Signed-off-by: Sean V Kelley <sean.v.kelley@intel.com>
---
drivers/pci/pcie/aer.c | 29 ++++++++++++++++-------------
1 file changed, 16 insertions(+), 13 deletions(-)

diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index 65dff5f3457a..6fe2d4ef0635 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -1361,23 +1361,26 @@ static pci_ers_result_t aer_root_reset(struct pci_dev *dev)
u32 reg32;
int rc;

-
- /* Disable Root's interrupt in response to error messages */
- pci_read_config_dword(dev, aer + PCI_ERR_ROOT_COMMAND, &reg32);
- reg32 &= ~ROOT_PORT_INTR_ON_MESG_MASK;
- pci_write_config_dword(dev, aer + PCI_ERR_ROOT_COMMAND, reg32);
+ if (pcie_aer_is_native(dev)) {
+ /* Disable Root's interrupt in response to error messages */
+ pci_read_config_dword(dev, aer + PCI_ERR_ROOT_COMMAND, &reg32);
+ reg32 &= ~ROOT_PORT_INTR_ON_MESG_MASK;
+ pci_write_config_dword(dev, aer + PCI_ERR_ROOT_COMMAND, reg32);
+ }

rc = pci_bus_error_reset(dev);
- pci_info(dev, "Root Port link has been reset\n");
+ pci_info(dev, "Root Port link has been reset (%d)\n", rc);

- /* Clear Root Error Status */
- pci_read_config_dword(dev, aer + PCI_ERR_ROOT_STATUS, &reg32);
- pci_write_config_dword(dev, aer + PCI_ERR_ROOT_STATUS, reg32);
+ if (pcie_aer_is_native(dev)) {
+ /* Clear Root Error Status */
+ pci_read_config_dword(dev, aer + PCI_ERR_ROOT_STATUS, &reg32);
+ pci_write_config_dword(dev, aer + PCI_ERR_ROOT_STATUS, reg32);

- /* Enable Root Port's interrupt in response to error messages */
- pci_read_config_dword(dev, aer + PCI_ERR_ROOT_COMMAND, &reg32);
- reg32 |= ROOT_PORT_INTR_ON_MESG_MASK;
- pci_write_config_dword(dev, aer + PCI_ERR_ROOT_COMMAND, reg32);
+ /* Enable Root Port's interrupt in response to error messages */
+ pci_read_config_dword(dev, aer + PCI_ERR_ROOT_COMMAND, &reg32);
+ reg32 |= ROOT_PORT_INTR_ON_MESG_MASK;
+ pci_write_config_dword(dev, aer + PCI_ERR_ROOT_COMMAND, reg32);
+ }

return rc ? PCI_ERS_RESULT_DISCONNECT : PCI_ERS_RESULT_RECOVERED;
}
--
2.29.2
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