Thread (9 messages) 9 messages, 2 authors, 2021-10-19

Re: [PATCH 2/6] MIPS: OCTEON: Remove redundant clearing of AER status registers

From: Bjorn Helgaas <helgaas@kernel.org>
Date: 2021-10-19 22:53:55
Also in: linux-mips, linux-pci, lkml

On Mon, Oct 04, 2021 at 11:29:28PM +0530, Naveen Naidu wrote:
e8635b484f64 ("MIPS: Add Cavium OCTEON PCI support.") added MIPS
specific code to enable PCIe and AER error reporting (*irrespective
of CONFIG_PCIEAER value*) because PCI core didn't do that at the time.

Currently when CONFIG_PCIEAER=y, the Uncorrectable Error status,
Correctable Error status and Root status registers are cleared
during the PCI Bus enumeration path by pci_aer_init() via
pci_init_capabilities()
So the current tree (before this patch) always clears these AER status
registers regardless of CONFIG_PCIEAER.

After this patch, we would clear them only if CONFIG_PCIEAER=y.  I
don't see anything in arch/mips that sets CONFIG_PCIEAER, so I'm
concerned we will no longer clear the AER status bits.

I only want to propose a change here if we're very confident that it
won't change any OCTEON behavior.
quoted hunk ↗ jump to hunk
It is now no longer necessary for Octeon code to clear AER status
registers since it's done by PCI core.

Signed-off-by: Naveen Naidu <redacted>
---
 arch/mips/pci/pci-octeon.c | 11 -----------
 1 file changed, 11 deletions(-)
diff --git a/arch/mips/pci/pci-octeon.c b/arch/mips/pci/pci-octeon.c
index fc29b85cfa92..8e8b282226cc 100644
--- a/arch/mips/pci/pci-octeon.c
+++ b/arch/mips/pci/pci-octeon.c
@@ -124,11 +124,6 @@ int pcibios_plat_dev_init(struct pci_dev *dev)
 	/* Find the Advanced Error Reporting capability */
 	pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
 	if (pos) {
-		/* Clear Uncorrectable Error Status */
-		pci_read_config_dword(dev, pos + PCI_ERR_UNCOR_STATUS,
-				      &dconfig);
-		pci_write_config_dword(dev, pos + PCI_ERR_UNCOR_STATUS,
-				       dconfig);
 		/* Enable reporting of all uncorrectable errors */
 		/* Uncorrectable Error Mask - turned on bits disable errors */
 		pci_write_config_dword(dev, pos + PCI_ERR_UNCOR_MASK, 0);
@@ -138,9 +133,6 @@ int pcibios_plat_dev_init(struct pci_dev *dev)
 		 * correctable, not if the error is reported.
 		 */
 		/* PCI_ERR_UNCOR_SEVER - Uncorrectable Error Severity */
-		/* Clear Correctable Error Status */
-		pci_read_config_dword(dev, pos + PCI_ERR_COR_STATUS, &dconfig);
-		pci_write_config_dword(dev, pos + PCI_ERR_COR_STATUS, dconfig);
 		/* Enable reporting of all correctable errors */
 		/* Correctable Error Mask - turned on bits disable errors */
 		pci_write_config_dword(dev, pos + PCI_ERR_COR_MASK, 0);
@@ -159,9 +151,6 @@ int pcibios_plat_dev_init(struct pci_dev *dev)
 				       PCI_ERR_ROOT_CMD_COR_EN |
 				       PCI_ERR_ROOT_CMD_NONFATAL_EN |
 				       PCI_ERR_ROOT_CMD_FATAL_EN);
-		/* Clear the Root status register */
-		pci_read_config_dword(dev, pos + PCI_ERR_ROOT_STATUS, &dconfig);
-		pci_write_config_dword(dev, pos + PCI_ERR_ROOT_STATUS, dconfig);
 	}
 
 	return 0;
-- 
2.25.1

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