[PATCH v4 09/18] EDAC/synopsys: Set actual DIMM ECC errors grain

[Serge Semin <fancer.lancer@gmail.com>]

It was wrong to set the DIMM errors grain parameter to just 1 byte because
DW uMCTL2 DDRC calculates ECC for each SDRAM word and passes it as an
additional byte of data to the memory chips. SDRAM word is the actual
DQ-bus width determined by the DQ-width set during the IP-core synthesize
and the DQ-bus mode (part of the DQ-bus actually used to get data from the
memory chips) selected during the DDR controller initial setup procedure.
Thus set the MCI DIMMs grain based on these parameters determined during
the DW uMCTL2 DDRC config getting procedure.

Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
---
 drivers/edac/synopsys_edac.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/edac/synopsys_edac.c b/drivers/edac/synopsys_edac.c
index e6288e135480..e10778cead63 100644
--- a/drivers/edac/synopsys_edac.c
+++ b/drivers/edac/synopsys_edac.c
@@ -26,9 +26,6 @@
 /* Number of channels per memory controller */
 #define SNPS_EDAC_NR_CHANS		1
 
-/* Granularity of reported error in bytes */
-#define SNPS_EDAC_ERR_GRAIN		1
-
 #define SNPS_EDAC_MSG_SIZE		256
 
 #define SNPS_EDAC_MOD_STRING		"snps_edac"
@@ -736,9 +733,12 @@ static void snps_init_csrows(struct mem_ctl_info *mci)
 	struct snps_edac_priv *priv = mci->pvt_info;
 	struct csrow_info *csi;
 	struct dimm_info *dimm;
-	u32 size, row;
+	u32 size, row, width;
 	int j;
 
+	/* Actual SDRAM-word width for which ECC is calculated */
+	width = 1U << (priv->info.dq_width - priv->info.dq_mode);
+
 	for (row = 0; row < mci->nr_csrows; row++) {
 		csi = mci->csrows[row];
 		size = snps_get_memsize();
@@ -748,7 +748,7 @@ static void snps_init_csrows(struct mem_ctl_info *mci)
 			dimm->edac_mode	= EDAC_SECDED;
 			dimm->mtype	= priv->info.sdram_mode;
 			dimm->nr_pages	= (size >> PAGE_SHIFT) / csi->nr_channels;
-			dimm->grain	= SNPS_EDAC_ERR_GRAIN;
+			dimm->grain	= width;
 			dimm->dtype	= priv->info.dev_cfg;
 		}
 	}
-- 
2.41.0