edac:i82975x fix 32bit compile and cleanup

the clean up achieves:
  1. fix warning on 32-bit compile
  2. reorder info extraction for clarity
  3. add error-trap diagnostic message
  4. handle ALL modes of memory configurations

Signed-off-by: Arvind R. <arvino55@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/edac/i82975x_edac.c

@@ -277,11 +277,9 @@ static void i82975x_get_error_info(struct mem_ctl_info *mci,
 static int i82975x_process_error_info(struct mem_ctl_info *mci,
 		struct i82975x_error_info *info, int handle_errors)
 {
-	int row, multi_chan, chan;
+	int row, chan;
 	unsigned long offst, page;
 
-	multi_chan = mci->csrows[0].nr_channels - 1;
-
 	if (!(info->errsts2 & 0x0003))
 		return 0;
 
@@ -294,20 +292,30 @@ static int i82975x_process_error_info(struct mem_ctl_info *mci,
 	}
 
 	page = (unsigned long) info->eap;
-	if (info->xeap & 1)
-		page |= 0x100000000ul;
-	chan = page & 1;
 	page >>= 1;
-	offst = page & ((1 << PAGE_SHIFT) - 1);
-	page >>= PAGE_SHIFT;
+	if (info->xeap & 1)
+		page |= 0x80000000;
+	page >>= (PAGE_SHIFT - 1);
 	row = edac_mc_find_csrow_by_page(mci, page);
 
+	if (row == -1)	{
+		i82975x_mc_printk(mci, KERN_ERR, "error processing EAP:\n"
+			"\tXEAP=%u\n"
+			"\t EAP=0x%08x\n"
+			"\tPAGE=0x%08x\n",
+			(info->xeap & 1) ? 1 : 0, info->eap, (unsigned int) page);
+		return 0;
+	}
+	chan = (mci->csrows[row].nr_channels == 1) ? 0 : info->eap & 1;
+	offst = info->eap
+			& ((1 << PAGE_SHIFT) -
+				(1 << mci->csrows[row].grain));
+
 	if (info->errsts & 0x0002)
 		edac_mc_handle_ue(mci, page, offst , row, "i82975x UE");
 	else
 		edac_mc_handle_ce(mci, page, offst, info->derrsyn, row,
-				multi_chan ? chan : 0,
-				"i82975x CE");
+				chan, "i82975x CE");
 
 	return 1;
 }
@@ -410,7 +418,7 @@ static void i82975x_init_csrows(struct mem_ctl_info *mci,
 		csrow->last_page = cumul_size - 1;
 		csrow->nr_pages = cumul_size - last_cumul_size;
 		last_cumul_size = cumul_size;
-		csrow->grain = 1 << 6;	/* I82975X_EAP has 64B resolution */
+		csrow->grain = 1 << 7;	/* 128Byte cache-line resolution */
 		csrow->mtype = MEM_DDR2; /* I82975x supports only DDR2 */
 		csrow->dtype = i82975x_dram_type(mch_window, index);
 		csrow->edac_mode = EDAC_SECDED; /* only supported */