edac: mpc85xx mask ecc syndrome correctly

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 manuals 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 <ptyser@xes-inc.com>
Signed-off-by: Doug Thompson <dougthompson@xmission.com>
Cc: Kumar Gala <galak@gate.crashing.org>
Cc: Dave Jiang <djiang@mvista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/edac/mpc85xx_edac.c b/drivers/edac/mpc85xx_edac.c
index ecd5928d7110491a71c6158a128f8f50552f9905..6d0114a1b77e827b9da1220068c9079018e65b47 100644 (file)
--- a/drivers/edac/mpc85xx_edac.c
+++ b/drivers/edac/mpc85xx_edac.c
@@ -672,6 +672,7 @@ static void mpc85xx_mc_check(struct mem_ctl_info *mci)
 {
        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_ctl_info *mci)
        }
 
        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_ctl_info *mci)
        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);
 

diff --git a/drivers/edac/mpc85xx_edac.h b/drivers/edac/mpc85xx_edac.h
index 52432ee7c4b98bf96a10e605116e04c00131481e..cb24df839460cd59c988e07ca828d71f564a9ff3 100644 (file)
--- a/drivers/edac/mpc85xx_edac.h
+++ b/drivers/edac/mpc85xx_edac.h
@@ -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