EDAC/igen6: Fix the flood of invalid error reports

The ECC_ERROR_LOG register of certain SoCs may contain the invalid value
~0, which results in a flood of invalid error reports in polling mode.

Fix the flood of invalid error reports by skipping the invalid ECC error
log value ~0.

Fixes: e14232afa944 ("EDAC/igen6: Add polling support")
Reported-by: Ramses <ramses@well-founded.dev>
Closes: https://lore.kernel.org/all/OISL8Rv--F-9@well-founded.dev/
Tested-by: Ramses <ramses@well-founded.dev>
Reported-by: John <therealgraysky@proton.me>
Closes: https://lore.kernel.org/all/p5YcxOE6M3Ncxpn2-Ia_wCt61EM4LwIiN3LroQvT_-G2jMrFDSOW5k2A9D8UUzD2toGpQBN1eI0sL5dSKnkO8iteZegLoQEj-DwQaMhGx4A=@proton.me/
Tested-by: John <therealgraysky@proton.me>
Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Link: https://lore.kernel.org/r/20250212083354.31919-1-qiuxu.zhuo@intel.com

diff --git a/drivers/edac/igen6_edac.c b/drivers/edac/igen6_edac.c
index fdf3a84fe6988b62ff608fd085241019e08ae992..595908af9e5c93e78480247daaf56dedbc3d9de2 100644 (file)
--- a/drivers/edac/igen6_edac.c
+++ b/drivers/edac/igen6_edac.c
@@ -785,13 +785,22 @@ static u64 ecclog_read_and_clear(struct igen6_imc *imc)
 {
        u64 ecclog = readq(imc->window + ECC_ERROR_LOG_OFFSET);
 
-       if (ecclog & (ECC_ERROR_LOG_CE | ECC_ERROR_LOG_UE)) {
-               /* Clear CE/UE bits by writing 1s */
-               writeq(ecclog, imc->window + ECC_ERROR_LOG_OFFSET);
-               return ecclog;
-       }
+       /*
+        * Quirk: The ECC_ERROR_LOG register of certain SoCs may contain
+        *        the invalid value ~0. This will result in a flood of invalid
+        *        error reports in polling mode. Skip it.
+        */
+       if (ecclog == ~0)
+               return 0;
 
-       return 0;
+       /* Neither a CE nor a UE. Skip it.*/
+       if (!(ecclog & (ECC_ERROR_LOG_CE | ECC_ERROR_LOG_UE)))
+               return 0;
+
+       /* Clear CE/UE bits by writing 1s */
+       writeq(ecclog, imc->window + ECC_ERROR_LOG_OFFSET);
+
+       return ecclog;
 }
 
 static void errsts_clear(struct igen6_imc *imc)