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[v4,14/25] PCI: rcar: Remove redundant error fabrication when device read fails

Message ID 83540eb3ae76a0d28bbe03d69d685a6d549b456b.1637243717.git.naveennaidu479@gmail.com
State New
Headers show
Series Unify PCI error response checking | expand

Commit Message

Naveen Naidu Nov. 18, 2021, 2:03 p.m. UTC 
An MMIO read from a PCI device that doesn't exist or doesn't respond
causes a PCI error. There's no real data to return to satisfy the
CPU read, so most hardware fabricates ~0 data.

The host controller drivers sets the error response values (~0) and
returns an error when faulty hardware read occurs. But the error
response value (~0) is already being set in PCI_OP_READ and
PCI_USER_READ_CONFIG whenever a read by host controller driver fails.

Thus, it's no longer necessary for the host controller drivers to
fabricate any error response.

This helps unify PCI error response checking and make error check
consistent and easier to find.

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Naveen Naidu <naveennaidu479@gmail.com>
---
 drivers/pci/controller/pcie-rcar-host.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)
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Patch

diff --git a/drivers/pci/controller/pcie-rcar-host.c b/drivers/pci/controller/pcie-rcar-host.c
index e12c2d8be05a..6bd5619fbbf4 100644
--- a/drivers/pci/controller/pcie-rcar-host.c
+++ b/drivers/pci/controller/pcie-rcar-host.c
@@ -159,10 +159,8 @@  static int rcar_pcie_read_conf(struct pci_bus *bus, unsigned int devfn,
 
 	ret = rcar_pcie_config_access(host, RCAR_PCI_ACCESS_READ,
 				      bus, devfn, where, val);
-	if (ret != PCIBIOS_SUCCESSFUL) {
-		*val = 0xffffffff;
+	if (ret != PCIBIOS_SUCCESSFUL)
 		return ret;
-	}
 
 	if (size == 1)
 		*val = (*val >> (BITS_PER_BYTE * (where & 3))) & 0xff;