2010-02-04 06:46:20

by dougthompson

[permalink] [raw]
Subject: [PATCH 3/7] edac: mpc85xx mask ecc syndrome correctly

From: Peter Tyser <[email protected]>

With a 64-bit wide data bus only the lowest 8-bits of the ECC syndrome
are relevant. With a 32-bit wide data bus only the lowest 16-bits are
relevant on most architectures.

Without this change, the ECC syndrome displayed can be mildly confusing,
eg:

EDAC MPC85xx MC1: syndrome: 0x25252525

When in reality the ECC syndrome is 0x25.

A variety of Freescale manual's say a variety of different things about
how to decode the CAPTURE_ECC (syndrome) register. I don't have a
system with a 32-bit bus to test on, but I believe the change is
correct. It'd be good to get an ACK from someone at Freescale
about this change though.

Signed-off-by: Peter Tyser <[email protected]>
Signed-off-by: Doug Thompson <[email protected]>
---
drivers/edac/mpc85xx_edac.c | 12 +++++++++++-
drivers/edac/mpc85xx_edac.h | 3 +++
2 files changed, 14 insertions(+), 1 deletions(-)

Index: linux-2.6.33-rc4/drivers/edac/mpc85xx_edac.c
===================================================================
--- linux-2.6.33-rc4.orig/drivers/edac/mpc85xx_edac.c 2010-01-13 00:16:00.000000000 -0700
+++ linux-2.6.33-rc4/drivers/edac/mpc85xx_edac.c 2010-01-13 00:16:06.000000000 -0700
@@ -672,6 +672,7 @@ static void mpc85xx_mc_check(struct mem_
{
struct mpc85xx_mc_pdata *pdata = mci->pvt_info;
struct csrow_info *csrow;
+ u32 bus_width;
u32 err_detect;
u32 syndrome;
u32 err_addr;
@@ -692,6 +693,15 @@ static void mpc85xx_mc_check(struct mem_
}

syndrome = in_be32(pdata->mc_vbase + MPC85XX_MC_CAPTURE_ECC);
+
+ /* Mask off appropriate bits of syndrome based on bus width */
+ bus_width = (in_be32(pdata->mc_vbase + MPC85XX_MC_DDR_SDRAM_CFG) &
+ DSC_DBW_MASK) ? 32 : 64;
+ if (bus_width == 64)
+ syndrome &= 0xff;
+ else
+ syndrome &= 0xffff;
+
err_addr = in_be32(pdata->mc_vbase + MPC85XX_MC_CAPTURE_ADDRESS);
pfn = err_addr >> PAGE_SHIFT;

@@ -707,7 +717,7 @@ static void mpc85xx_mc_check(struct mem_
mpc85xx_mc_printk(mci, KERN_ERR, "Capture Data Low: %#8.8x\n",
in_be32(pdata->mc_vbase +
MPC85XX_MC_CAPTURE_DATA_LO));
- mpc85xx_mc_printk(mci, KERN_ERR, "syndrome: %#8.8x\n", syndrome);
+ mpc85xx_mc_printk(mci, KERN_ERR, "syndrome: %#2.2x\n", syndrome);
mpc85xx_mc_printk(mci, KERN_ERR, "err addr: %#8.8x\n", err_addr);
mpc85xx_mc_printk(mci, KERN_ERR, "PFN: %#8.8x\n", pfn);

Index: linux-2.6.33-rc4/drivers/edac/mpc85xx_edac.h
===================================================================
--- linux-2.6.33-rc4.orig/drivers/edac/mpc85xx_edac.h 2010-01-13 00:15:28.000000000 -0700
+++ linux-2.6.33-rc4/drivers/edac/mpc85xx_edac.h 2010-01-13 00:16:06.000000000 -0700
@@ -48,6 +48,9 @@
#define DSC_MEM_EN 0x80000000
#define DSC_ECC_EN 0x20000000
#define DSC_RD_EN 0x10000000
+#define DSC_DBW_MASK 0x00180000
+#define DSC_DBW_32 0x00080000
+#define DSC_DBW_64 0x00000000

#define DSC_SDTYPE_MASK 0x07000000