linux-kernel - [PATCH 1/1] MIPS: Routerboard 532: Fix vendor retry check code

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Message-Id: <20240508120700.51374-1-ilpo.jarvinen@linux.intel.com>
Date: Wed,  8 May 2024 15:07:00 +0300
From: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
To: Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
	Florian Fainelli <florian.fainelli@...ecomint.eu>,
	Ralf Baechle <ralf@...ux-mips.org>,
	Phil Sutter <n0-1@...ewrt.org>,
	linux-mips@...r.kernel.org,
	linux-kernel@...r.kernel.org
Cc: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Subject: [PATCH 1/1] MIPS: Routerboard 532: Fix vendor retry check code

read_config_dword() contains strange condition checking ret for a
number of values. The ret variable, however, is always zero because
config_access() never returns anything else. Thus, the retry is always
taken until number of tries is exceeded.

The code looks like it wants to check *val instead of ret to see if the
read gave an error response.

Fixes: 73b4390fb234 ("[MIPS] Routerboard 532: Support for base system")
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
--

IMPORTANT NOTE TO MAINTAINER:

This change has potential of breaking something and I don't have HW to
test this with. I only came across it while going through all PCIBIOS_*
call chains. Clearly the current code non-sensical so something is not
right but whether this is the right way to solve the problem, I'm not
entirely sure because it will make small change into the behavior.
---
 arch/mips/pci/ops-rc32434.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/mips/pci/ops-rc32434.c b/arch/mips/pci/ops-rc32434.c
index 874ed6df9768..34b9323bdabb 100644
--- a/arch/mips/pci/ops-rc32434.c
+++ b/arch/mips/pci/ops-rc32434.c
@@ -112,8 +112,8 @@ static int read_config_dword(struct pci_bus *bus, unsigned int devfn,
 	 * gives them time to settle
 	 */
 	if (where == PCI_VENDOR_ID) {
-		if (ret == 0xffffffff || ret == 0x00000000 ||
-		    ret == 0x0000ffff || ret == 0xffff0000) {
+		if (*val == 0xffffffff || *val == 0x00000000 ||
+		    *val == 0x0000ffff || *val == 0xffff0000) {
 			if (delay > 4)
 				return 0;
 			delay *= 2;
-- 
2.39.2