path: root/i82975x-edac-fix.patch

commit 9370a8d717720f6b17221490fea8d798396d9f2f
Author: Mauro Carvalho Chehab <mchehab@redhat.com>
Date:   Mon Oct 15 21:49:35 2012 -0300

    i82975x_edac: Use the edac standard debug macro
    
    Instead of declaring its own debug macro, that requires
    to uncomment part of the code, use the edac standard macro
    to add the debug code, and the edac debug level to print it,
    just like any other EDAC driver.
    
    Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

diff --git a/drivers/edac/i82975x_edac.c b/drivers/edac/i82975x_edac.c
index a980204..f998d2c 100644
--- a/drivers/edac/i82975x_edac.c
+++ b/drivers/edac/i82975x_edac.c
@@ -435,11 +435,9 @@ static void i82975x_init_csrows(struct mem_ctl_info *mci,
 	}
 }
 
-/* #define  i82975x_DEBUG_IOMEM */
-
-#ifdef i82975x_DEBUG_IOMEM
-static void i82975x_print_dram_timings(void __iomem *mch_window)
+static void i82975x_print_dram_config(void __iomem *mch_window, u32 mchbar, u32 *drc)
 {
+#ifdef CONFIG_EDAC_DEBUG
 	/*
 	 * The register meanings are from Intel specs;
 	 * (shows 13-5-5-5 for 800-DDR2)
@@ -448,26 +446,63 @@ static void i82975x_print_dram_timings(void __iomem *mch_window)
 	 */
 	static const int caslats[4] = { 5, 4, 3, 6 };
 	u32	dtreg[2];
+	u8 c0drb[4];
+	u8 c1drb[4];
+
+	if (!edac_debug_level)
+		return;
+
+	i82975x_printk(KERN_INFO, "MCHBAR real = %0x, remapped = %p\n",
+		       mchbar, mch_window);
+
+	c0drb[0] = readb(mch_window + I82975X_DRB_CH0R0);
+	c0drb[1] = readb(mch_window + I82975X_DRB_CH0R1);
+	c0drb[2] = readb(mch_window + I82975X_DRB_CH0R2);
+	c0drb[3] = readb(mch_window + I82975X_DRB_CH0R3);
+	c1drb[0] = readb(mch_window + I82975X_DRB_CH1R0);
+	c1drb[1] = readb(mch_window + I82975X_DRB_CH1R1);
+	c1drb[2] = readb(mch_window + I82975X_DRB_CH1R2);
+	c1drb[3] = readb(mch_window + I82975X_DRB_CH1R3);
+	i82975x_printk(KERN_INFO, "DRBCH0R0 = 0x%02x\n", c0drb[0]);
+	i82975x_printk(KERN_INFO, "DRBCH0R1 = 0x%02x\n", c0drb[1]);
+	i82975x_printk(KERN_INFO, "DRBCH0R2 = 0x%02x\n", c0drb[2]);
+	i82975x_printk(KERN_INFO, "DRBCH0R3 = 0x%02x\n", c0drb[3]);
+	i82975x_printk(KERN_INFO, "DRBCH1R0 = 0x%02x\n", c1drb[0]);
+	i82975x_printk(KERN_INFO, "DRBCH1R1 = 0x%02x\n", c1drb[1]);
+	i82975x_printk(KERN_INFO, "DRBCH1R2 = 0x%02x\n", c1drb[2]);
+	i82975x_printk(KERN_INFO, "DRBCH1R3 = 0x%02x\n", c1drb[3]);
+
+	i82975x_printk(KERN_INFO, "DRC_CH0 = %0x, %s\n", drc[0],
+		       ((drc[0] >> 21) & 3) == 1 ?
+				"ECC enabled" : "ECC disabled");
+	i82975x_printk(KERN_INFO, "DRC_CH1 = %0x, %s\n", drc[1],
+		       ((drc[1] >> 21) & 3) == 1 ?
+		       "ECC enabled" : "ECC disabled");
+
+	i82975x_printk(KERN_INFO, "C0 BNKARC = %0x\n",
+		readw(mch_window + I82975X_C0BNKARC));
+	i82975x_printk(KERN_INFO, "C1 BNKARC = %0x\n",
+		readw(mch_window + I82975X_C1BNKARC));
 
 	dtreg[0] = readl(mch_window + 0x114);
 	dtreg[1] = readl(mch_window + 0x194);
-	i82975x_printk(KERN_INFO, "DRAM Timings :     Ch0    Ch1\n"
+	i82975x_printk(KERN_INFO,
+		"DRAM Timings :  Ch0    Ch1\n"
 		"                RAS Active Min = %d     %d\n"
 		"                CAS latency    =  %d      %d\n"
 		"                RAS to CAS     =  %d      %d\n"
 		"                RAS precharge  =  %d      %d\n",
 		(dtreg[0] >> 19 ) & 0x0f,
-			(dtreg[1] >> 19) & 0x0f,
+		(dtreg[1] >> 19) & 0x0f,
 		caslats[(dtreg[0] >> 8) & 0x03],
-			caslats[(dtreg[1] >> 8) & 0x03],
+		caslats[(dtreg[1] >> 8) & 0x03],
 		((dtreg[0] >> 4) & 0x07) + 2,
-			((dtreg[1] >> 4) & 0x07) + 2,
+		((dtreg[1] >> 4) & 0x07) + 2,
 		(dtreg[0] & 0x07) + 2,
-			(dtreg[1] & 0x07) + 2
+		(dtreg[1] & 0x07) + 2
 	);
-
-}
 #endif
+}
 
 static int i82975x_probe1(struct pci_dev *pdev, int dev_idx)
 {
@@ -480,10 +515,6 @@ static int i82975x_probe1(struct pci_dev *pdev, int dev_idx)
 	u32 drc[2];
 	struct i82975x_error_info discard;
 	int	chans;
-#ifdef i82975x_DEBUG_IOMEM
-	u8 c0drb[4];
-	u8 c1drb[4];
-#endif
 
 	edac_dbg(0, "\n");
 
@@ -495,45 +526,11 @@ static int i82975x_probe1(struct pci_dev *pdev, int dev_idx)
 	mchbar &= 0xffffc000;	/* bits 31:14 used for 16K window */
 	mch_window = ioremap_nocache(mchbar, 0x1000);
 
-#ifdef i82975x_DEBUG_IOMEM
-	i82975x_printk(KERN_INFO, "MCHBAR real = %0x, remapped = %p\n",
-					mchbar, mch_window);
-
-	c0drb[0] = readb(mch_window + I82975X_DRB_CH0R0);
-	c0drb[1] = readb(mch_window + I82975X_DRB_CH0R1);
-	c0drb[2] = readb(mch_window + I82975X_DRB_CH0R2);
-	c0drb[3] = readb(mch_window + I82975X_DRB_CH0R3);
-	c1drb[0] = readb(mch_window + I82975X_DRB_CH1R0);
-	c1drb[1] = readb(mch_window + I82975X_DRB_CH1R1);
-	c1drb[2] = readb(mch_window + I82975X_DRB_CH1R2);
-	c1drb[3] = readb(mch_window + I82975X_DRB_CH1R3);
-	i82975x_printk(KERN_INFO, "DRBCH0R0 = 0x%02x\n", c0drb[0]);
-	i82975x_printk(KERN_INFO, "DRBCH0R1 = 0x%02x\n", c0drb[1]);
-	i82975x_printk(KERN_INFO, "DRBCH0R2 = 0x%02x\n", c0drb[2]);
-	i82975x_printk(KERN_INFO, "DRBCH0R3 = 0x%02x\n", c0drb[3]);
-	i82975x_printk(KERN_INFO, "DRBCH1R0 = 0x%02x\n", c1drb[0]);
-	i82975x_printk(KERN_INFO, "DRBCH1R1 = 0x%02x\n", c1drb[1]);
-	i82975x_printk(KERN_INFO, "DRBCH1R2 = 0x%02x\n", c1drb[2]);
-	i82975x_printk(KERN_INFO, "DRBCH1R3 = 0x%02x\n", c1drb[3]);
-#endif
-
 	drc[0] = readl(mch_window + I82975X_DRC_CH0M0);
 	drc[1] = readl(mch_window + I82975X_DRC_CH1M0);
-#ifdef i82975x_DEBUG_IOMEM
-	i82975x_printk(KERN_INFO, "DRC_CH0 = %0x, %s\n", drc[0],
-			((drc[0] >> 21) & 3) == 1 ?
-				"ECC enabled" : "ECC disabled");
-	i82975x_printk(KERN_INFO, "DRC_CH1 = %0x, %s\n", drc[1],
-			((drc[1] >> 21) & 3) == 1 ?
-				"ECC enabled" : "ECC disabled");
 
-	i82975x_printk(KERN_INFO, "C0 BNKARC = %0x\n",
-		readw(mch_window + I82975X_C0BNKARC));
-	i82975x_printk(KERN_INFO, "C1 BNKARC = %0x\n",
-		readw(mch_window + I82975X_C1BNKARC));
-	i82975x_print_dram_timings(mch_window);
-	goto fail1;
-#endif
+	i82975x_print_dram_config(mch_window, mchbar, drc);
+
 	if (!(((drc[0] >> 21) & 3) == 1 || ((drc[1] >> 21) & 3) == 1)) {
 		i82975x_printk(KERN_INFO, "ECC disabled on both channels.\n");
 		goto fail1;

commit 8992ed2f4295eab137e1713fa16be5546a759373
Author: Mauro Carvalho Chehab <mchehab@redhat.com>
Date:   Mon Oct 15 21:48:48 2012 -0300

    i82975x_edac: Fix dimm label initialization
    
    The driver has only 4 hardcoded labels, but allows much more memory.
    Fix it by removing the hardcoded logic, using snprintf() instead.
    
    [   19.833972] general protection fault: 0000 [#1] SMP
    [   19.837733] Modules linked in: i82975x_edac(+) edac_core firewire_ohci firewire_core crc_itu_t nouveau mxm_wmi wmi video i2c_algo_bit drm_kms_helper ttm drm i2c_core
    [   19.837733] CPU 0
    [   19.837733] Pid: 390, comm: udevd Not tainted 3.6.1-1.fc17.x86_64.debug #1 Dell Inc.                 Precision WorkStation 390    /0MY510
    [   19.837733] RIP: 0010:[<ffffffff813463a8>]  [<ffffffff813463a8>] strncpy+0x18/0x30
    [   19.837733] RSP: 0018:ffff880078535b68  EFLAGS: 00010202
    [   19.837733] RAX: ffff880069fa9708 RBX: ffff880078588000 RCX: ffff880069fa9708
    [   19.837733] RDX: 000000000000001f RSI: 5f706f5f63616465 RDI: ffff880069fa9708
    [   19.837733] RBP: ffff880078535b68 R08: ffff880069fa9727 R09: 000000000000fffe
    [   19.837733] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000003
    [   19.837733] R13: 0000000000000000 R14: ffff880069fa9290 R15: ffff880079624a80
    [   19.837733] FS:  00007f3de01ee840(0000) GS:ffff88007c400000(0000) knlGS:0000000000000000
    [   19.837733] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    [   19.837733] CR2: 00007f3de00b9000 CR3: 0000000078dbc000 CR4: 00000000000007f0
    [   19.837733] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
    [   19.837733] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
    [   19.837733] Process udevd (pid: 390, threadinfo ffff880078534000, task ffff880079642450)
    [   19.837733] Stack:
    [   19.837733]  ffff880078535c18 ffffffffa017c6b8 00040000816d627f ffff880079624a88
    [   19.837733]  ffffc90004cd6000 ffff880079624520 ffff88007ac21148 0000000000000000
    [   19.837733]  0000000000000000 0004000000000000 feda000078535bc8 ffffffff810d696d
    [   19.837733] Call Trace:
    [   19.837733]  [<ffffffffa017c6b8>] i82975x_init_one+0x2e6/0x3e6 [i82975x_edac]
    ...
    
    Fix bug reported at:
    	https://bugzilla.redhat.com/show_bug.cgi?id=848149
    And, very likely:
    	https://bbs.archlinux.org/viewtopic.php?id=148033
    	https://bugzilla.kernel.org/show_bug.cgi?id=47171
    
    Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
    Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

diff --git a/drivers/edac/i82975x_edac.c b/drivers/edac/i82975x_edac.c
index 069e26c..a980204 100644
--- a/drivers/edac/i82975x_edac.c
+++ b/drivers/edac/i82975x_edac.c
@@ -370,10 +370,6 @@ static enum dev_type i82975x_dram_type(void __iomem *mch_window, int rank)
 static void i82975x_init_csrows(struct mem_ctl_info *mci,
 		struct pci_dev *pdev, void __iomem *mch_window)
 {
-	static const char *labels[4] = {
-							"DIMM A1", "DIMM A2",
-							"DIMM B1", "DIMM B2"
-						};
 	struct csrow_info *csrow;
 	unsigned long last_cumul_size;
 	u8 value;
@@ -423,9 +419,10 @@ static void i82975x_init_csrows(struct mem_ctl_info *mci,
 			dimm = mci->csrows[index]->channels[chan]->dimm;
 
 			dimm->nr_pages = nr_pages / csrow->nr_channels;
-			strncpy(csrow->channels[chan]->dimm->label,
-					labels[(index >> 1) + (chan * 2)],
-					EDAC_MC_LABEL_LEN);
+
+			snprintf(csrow->channels[chan]->dimm->label, EDAC_MC_LABEL_LEN, "DIMM %c%d",
+				 (chan == 0) ? 'A' : 'B',
+				 index);
 			dimm->grain = 1 << 7;	/* 128Byte cache-line resolution */
 			dimm->dtype = i82975x_dram_type(mch_window, index);
 			dimm->mtype = MEM_DDR2; /* I82975x supports only DDR2 */
commit 6e7636c972951ba0c6c640758b1dcc7667cb2415
Author: Mauro Carvalho Chehab <mchehab@redhat.com>
Date:   Tue Oct 16 15:30:23 2012 -0300

    i82975x_edac: rewrite the entire fill/report logic
    
    There are so many bugs at the fill/error report logic that
    the code ended by being re-written.
    
    Issues solved:
    
    - DIMM labels were "randomly" filled: they won't
      match the memory layout, due to a series of bugs on it;
    
    - The memory controller supports 3 different modes:
      single, dual interleaved and dual async. The logic there were
      written considering the dual interleaved one (yet, some
      single mode support was there);
    
    - The boundary limit to decide on each channel the error happens,
      at dual interleaved mode, is given by bit 6 of the error address,
      and not bit 1. The practical effect is that Corrected errors
      will have a 50% of chance of pointing to the right DIMM. Only
      the DIMM pair logic were OK;
    
    - The asymetric mode weren't properly supported. The driver would
      handle an asymetric mode as 'single mode', with doesn't actually
      match it, creating some weird real/virtual DIMM mappings.
    
    - Some other random bugs got fixed.
    
    Tested on a Dell Precision N390, on dual interleaved mode.
    
    Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

diff --git a/drivers/edac/i82975x_edac.c b/drivers/edac/i82975x_edac.c
index f998d2c..082e91e 100644
--- a/drivers/edac/i82975x_edac.c
+++ b/drivers/edac/i82975x_edac.c
@@ -6,7 +6,17 @@
  * GNU General Public License.
  *
  * Written by Arvind R.
- *   Copied from i82875p_edac.c source:
+ *   Copied from i82875p_edac.c source,
+ *
+ * (c) 2012 Mauro Carvalho Chehab <mchehab@redhat.com>
+ *	Driver re-written in order to fix lots of issues on it:
+ *		- Fix Single Mode;
+ *		- Add support for Asymetrical mode
+ *		- Fix several issues with Interleaved mode
+ *		- Fix memory label logic
+ *
+ * Intel datasheet: Intel(R) 975X Express Chipset Datasheet
+ *	http://www.intel.com/assets/pdf/datasheet/310158.pdf
  */
 
 #include <linux/module.h>
@@ -29,8 +39,8 @@
 #define PCI_DEVICE_ID_INTEL_82975_0	0x277c
 #endif				/* PCI_DEVICE_ID_INTEL_82975_0 */
 
-#define I82975X_NR_DIMMS		8
-#define I82975X_NR_CSROWS(nr_chans)	(I82975X_NR_DIMMS / (nr_chans))
+#define DIMMS_PER_CHANNEL	4
+#define NUM_CHANNELS		2
 
 /* Intel 82975X register addresses - device 0 function 0 - DRAM Controller */
 #define I82975X_EAP		0x58	/* Dram Error Address Pointer (32b)
@@ -112,7 +122,7 @@ NOTE: Only ONE of the three must be enabled
 /* NOTE: Following addresses have to indexed using MCHBAR offset (44h, 32b) */
 /* Intel 82975x memory mapped register space */
 
-#define I82975X_DRB_SHIFT 25	/* fixed 32MiB grain */
+#define I82975X_DRB_SHIFT 25	/* fixed 2^25 = 32 MiB grain */
 
 #define I82975X_DRB		0x100	/* DRAM Row Boundary (8b x 8)
 					 *
@@ -152,6 +162,10 @@ NOTE: Only ONE of the three must be enabled
 #define I82975X_DRA_CH1R01		0x188
 #define I82975X_DRA_CH1R23		0x189
 
+/* Channels 0/1 DRAM Timing Register 1 */
+#define I82975X_C0DRT1			0x114
+#define I82975X_C1DRT1			0x194
+
 
 #define I82975X_BNKARC	0x10e /* Type of device in each rank - Bank Arch (16b)
 					 *
@@ -206,8 +220,16 @@ enum i82975x_chips {
 	I82975X = 0,
 };
 
+struct mem_range {
+	u32 start, end;
+};
+
 struct i82975x_pvt {
-	void __iomem *mch_window;
+	void __iomem		*mch_window;
+	int 			num_channels;
+	bool			is_symetric;
+	u8			drb[DIMMS_PER_CHANNEL][NUM_CHANNELS];
+	struct mem_range	page[DIMMS_PER_CHANNEL][NUM_CHANNELS];
 };
 
 struct i82975x_dev_info {
@@ -278,8 +300,10 @@ 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, chan;
-	unsigned long offst, page;
+	struct i82975x_pvt *pvt = mci->pvt_info;
+	struct mem_range	*range;
+	unsigned int		row, chan, grain;
+	unsigned long		offst, page;
 
 	if (!(info->errsts2 & 0x0003))
 		return 0;
@@ -293,36 +317,70 @@ static int i82975x_process_error_info(struct mem_ctl_info *mci,
 		info->errsts = info->errsts2;
 	}
 
+	/* Calculate page and offset of the error */
+
 	page = (unsigned long) info->eap;
 	page >>= 1;
+
 	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;
+
+	if (pvt->is_symetric)
+		grain = 1 << 7;
+	else
+		grain = 1 << 6;
+
+	offst = info->eap & ((1 << PAGE_SHIFT) - (1 << grain));
+
+	/*
+	 * Search for the DIMM chip that match the error page.
+	 *
+	 * On Symmetric mode, this will always return channel = 0, as
+	 * both channel A and B ranges are identical.
+	 * A latter logic will determinte the channel on symetric mode
+	 *
+	 * On asymetric mode or single mode, there will be just one match,
+	 * that will point to the csrow with the error.
+	 */
+	for (chan = 0; chan < pvt->num_channels; chan++) {
+		for (row = 0; row < DIMMS_PER_CHANNEL; row++) {
+			range = &pvt->page[row][chan];
+
+			if (page >= range->start && page <= range->end)
+				goto found;
+		}
 	}
-	chan = (mci->csrows[row]->nr_channels == 1) ? 0 : info->eap & 1;
-	offst = info->eap
-			& ((1 << PAGE_SHIFT) -
-			   (1 << mci->csrows[row]->channels[chan]->dimm->grain));
+	chan = -1;
+	row = -1;
 
-	if (info->errsts & 0x0002)
+found:
+	if (info->errsts & 0x0002) {
+		/*
+		 * On uncorrected error, ECC doesn't allow do determine the
+		 * channel where the error has occurred.
+		 */
 		edac_mc_handle_error(HW_EVENT_ERR_UNCORRECTED, mci, 1,
 				     page, offst, 0,
 				     row, -1, -1,
 				     "i82975x UE", "");
-	else
-		edac_mc_handle_error(HW_EVENT_ERR_CORRECTED, mci, 1,
-				     page, offst, info->derrsyn,
-				     row, chan ? chan : 0, -1,
-				     "i82975x CE", "");
+		return 1;
+	}
+
+	if (pvt->is_symetric && row >= 0) {
+		/*
+		 * On Symetric mode, the memory switch happens after each
+		 * cache line (64 byte boundary). Channel 0 goes first.
+		 */
+		if (info->eap & (1 << 6))
+			chan = 1;
+		else
+			chan = 0;
+	}
+	edac_mc_handle_error(HW_EVENT_ERR_CORRECTED, mci, 1,
+				page, offst, info->derrsyn,
+				row, chan, -1,
+				"i82975x CE", "");
 
 	return 1;
 }
@@ -331,111 +389,143 @@ static void i82975x_check(struct mem_ctl_info *mci)
 {
 	struct i82975x_error_info info;
 
-	edac_dbg(1, "MC%d\n", mci->mc_idx);
+	edac_dbg(4, "MC%d\n", mci->mc_idx);
 	i82975x_get_error_info(mci, &info);
 	i82975x_process_error_info(mci, &info, 1);
 }
 
-/* Return 1 if dual channel mode is active.  Else return 0. */
-static int dual_channel_active(void __iomem *mch_window)
+/**
+ * detect_memory_style - Detect on what mode the memory controller is programmed
+ *
+ * @pvt:		pointer to the private structure
+ *
+ * This function detects how many channels are in use, and if the memory
+ * controller is in symetric (interleaved) or asymetric mode. There's no
+ * need to distinguish between asymetric and single mode, as the routines
+ * that fill the csrows data and handle error are written in order to handle
+ * both at the same way.
+ */
+static void detect_memory_style(struct i82975x_pvt *pvt)
 {
-	/*
-	 * We treat interleaved-symmetric configuration as dual-channel - EAP's
-	 * bit-0 giving the channel of the error location.
-	 *
-	 * All other configurations are treated as single channel - the EAP's
-	 * bit-0 will resolve ok in symmetric area of mixed
-	 * (symmetric/asymmetric) configurations
-	 */
-	u8	drb[4][2];
 	int	row;
-	int    dualch;
+	bool has_chan_a = false;
+	bool has_chan_b = false;
+
+	pvt->is_symetric = true;
+	pvt->num_channels = 0;
+
+	for (row = 0; row < DIMMS_PER_CHANNEL; row++) {
+		pvt->drb[row][0] = readb(pvt->mch_window + I82975X_DRB + row);
+		pvt->drb[row][1] = readb(pvt->mch_window + I82975X_DRB + row + 0x80);
+
+		/* On symetric mode, both channels have the same boundaries */
+		if (pvt->drb[row][0] != pvt->drb[row][1])
+			pvt->is_symetric = false;
 
-	for (dualch = 1, row = 0; dualch && (row < 4); row++) {
-		drb[row][0] = readb(mch_window + I82975X_DRB + row);
-		drb[row][1] = readb(mch_window + I82975X_DRB + row + 0x80);
-		dualch = dualch && (drb[row][0] == drb[row][1]);
+		if (pvt->drb[row][0])
+			has_chan_a = true;
+		if (pvt->drb[row][1])
+			has_chan_b = true;
 	}
-	return dualch;
-}
 
-static enum dev_type i82975x_dram_type(void __iomem *mch_window, int rank)
-{
-	/*
-	 * ECC is possible on i92975x ONLY with DEV_X8
-	 */
-	return DEV_X8;
+	if (has_chan_a)
+		pvt->num_channels++;
+
+	if (has_chan_b)
+		pvt->num_channels++;
 }
 
 static void i82975x_init_csrows(struct mem_ctl_info *mci,
-		struct pci_dev *pdev, void __iomem *mch_window)
+				struct i82975x_pvt *pvt,
+				struct pci_dev *pdev)
 {
-	struct csrow_info *csrow;
-	unsigned long last_cumul_size;
-	u8 value;
-	u32 cumul_size, nr_pages;
-	int index, chan;
-	struct dimm_info *dimm;
-	enum dev_type dtype;
-
-	last_cumul_size = 0;
+	struct dimm_info	*dimm;
+	struct mem_range	*range;
+	u8			boundary;
+	u32			initial_page = 0, last_page;
+	int			row, chan;
 
 	/*
-	 * 82875 comment:
-	 * The dram row boundary (DRB) reg values are boundary address
-	 * for each DRAM row with a granularity of 32 or 64MB (single/dual
-	 * channel operation).  DRB regs are cumulative; therefore DRB7 will
-	 * contain the total memory contained in all rows.
-	 *
+	 * This chipset provides 3 address modes:
+	 * Single channel - either Channel A or channel B is filled
+	 * Dual channel, interleaved: Memory is organized in pairs,
+	 * 	where channel A gets the lower address for each pair
+	 * Dual channel, asymmetric: Channel A memory goes first.
+	 * In order to cover all modes, we need to start describing
+	 * memories considering the dual channel, asymmetric one.
 	 */
 
-	for (index = 0; index < mci->nr_csrows; index++) {
-		csrow = mci->csrows[index];
-
-		value = readb(mch_window + I82975X_DRB + index +
-					((index >= 4) ? 0x80 : 0));
-		cumul_size = value;
-		cumul_size <<= (I82975X_DRB_SHIFT - PAGE_SHIFT);
-		/*
-		 * Adjust cumul_size w.r.t number of channels
-		 *
-		 */
-		if (csrow->nr_channels > 1)
-			cumul_size <<= 1;
-		edac_dbg(3, "(%d) cumul_size 0x%x\n", index, cumul_size);
-
-		nr_pages = cumul_size - last_cumul_size;
-		if (!nr_pages)
-			continue;
-
+	for (chan = 0; chan < pvt->num_channels; chan++) {
 		/*
-		 * Initialise dram labels
-		 * index values:
-		 *   [0-7] for single-channel; i.e. csrow->nr_channels = 1
-		 *   [0-3] for dual-channel; i.e. csrow->nr_channels = 2
+		 * On symetric mode, both channels start from address 0
 		 */
-		dtype = i82975x_dram_type(mch_window, index);
-		for (chan = 0; chan < csrow->nr_channels; chan++) {
-			dimm = mci->csrows[index]->channels[chan]->dimm;
-
-			dimm->nr_pages = nr_pages / csrow->nr_channels;
-
-			snprintf(csrow->channels[chan]->dimm->label, EDAC_MC_LABEL_LEN, "DIMM %c%d",
-				 (chan == 0) ? 'A' : 'B',
-				 index);
-			dimm->grain = 1 << 7;	/* 128Byte cache-line resolution */
-			dimm->dtype = i82975x_dram_type(mch_window, index);
+		if (pvt->is_symetric)
+			initial_page = 0;
+
+		for (row = 0; row < DIMMS_PER_CHANNEL; row++) {
+			boundary = pvt->drb[row][chan];
+			dimm = mci->csrows[row]->channels[chan]->dimm;
+
+			last_page = boundary << (I82975X_DRB_SHIFT - PAGE_SHIFT);
+			dimm->nr_pages = last_page - initial_page;
+			if (!dimm->nr_pages)
+				continue;
+
+			range = &pvt->page[row][chan];
+			range->start = initial_page;
+			range->end = range->start + dimm->nr_pages - 1;
+
+			/*
+			 * Grain is one cache-line:
+			 * On dual symetric mode, it is 128 Bytes;
+			 * On single mode or asymetric, it is 64 bytes.
+			 */
+			if (pvt->is_symetric) {
+				dimm->grain = 1 << 7;
+
+				/*
+				 * In dual interleaved mode, the addresses
+				 * need to be multiplied by 2, as both
+				 * channels are interlaced, and the boundary
+				 * limit there actually match each DIMM size
+				 */
+				range->start <<= 1;
+				range->end <<= 1;
+			} else {
+				dimm->grain = 1 << 6;
+			}
+
+			snprintf(dimm->label,
+				 EDAC_MC_LABEL_LEN, "DIMM %c%d",
+				 (chan == 0) ? 'A' : 'B', row);
 			dimm->mtype = MEM_DDR2; /* I82975x supports only DDR2 */
 			dimm->edac_mode = EDAC_SECDED; /* only supported */
-		}
 
-		csrow->first_page = last_cumul_size;
-		csrow->last_page = cumul_size - 1;
-		last_cumul_size = cumul_size;
+			/*
+			 * This chipset supports both x8 and x16 memories,
+			 * but datasheet doesn't describe how to distinguish
+			 * between them.
+			 *
+			 * Also, the "Rank" comment at initial_page 17 says that
+			 * ECC is only available with x8 memories. As this
+			 * driver doesn't even initialize without ECC, better
+			 * to assume that everything is x8. This is not
+			 * actually true, on a mixed ECC/non-ECC scenario.
+			 */
+			dimm->dtype = DEV_X8;
+
+			edac_dbg(1,
+				 "%s: from page 0x%08x to 0x%08x (size: 0x%08x pages)\n",
+				 dimm->label,
+				 range->start, range->end,
+				 dimm->nr_pages);
+			initial_page = last_page;
+		}
 	}
 }
 
-static void i82975x_print_dram_config(void __iomem *mch_window, u32 mchbar, u32 *drc)
+static void i82975x_print_dram_config(struct i82975x_pvt *pvt,
+				      u32 mchbar, u32 *drc)
 {
 #ifdef CONFIG_EDAC_DEBUG
 	/*
@@ -444,63 +534,57 @@ static void i82975x_print_dram_config(void __iomem *mch_window, u32 mchbar, u32
 	 * Asus P5W Bios reports 15-5-4-4
 	 * What's your religion?
 	 */
-	static const int caslats[4] = { 5, 4, 3, 6 };
-	u32	dtreg[2];
-	u8 c0drb[4];
-	u8 c1drb[4];
+	static const int	caslats[4] = { 5, 4, 3, 6 };
+	u32			dtreg[2];
+	int			row;
 
+	/* Show memory config if debug level is 1 or upper */
 	if (!edac_debug_level)
 		return;
 
 	i82975x_printk(KERN_INFO, "MCHBAR real = %0x, remapped = %p\n",
-		       mchbar, mch_window);
-
-	c0drb[0] = readb(mch_window + I82975X_DRB_CH0R0);
-	c0drb[1] = readb(mch_window + I82975X_DRB_CH0R1);
-	c0drb[2] = readb(mch_window + I82975X_DRB_CH0R2);
-	c0drb[3] = readb(mch_window + I82975X_DRB_CH0R3);
-	c1drb[0] = readb(mch_window + I82975X_DRB_CH1R0);
-	c1drb[1] = readb(mch_window + I82975X_DRB_CH1R1);
-	c1drb[2] = readb(mch_window + I82975X_DRB_CH1R2);
-	c1drb[3] = readb(mch_window + I82975X_DRB_CH1R3);
-	i82975x_printk(KERN_INFO, "DRBCH0R0 = 0x%02x\n", c0drb[0]);
-	i82975x_printk(KERN_INFO, "DRBCH0R1 = 0x%02x\n", c0drb[1]);
-	i82975x_printk(KERN_INFO, "DRBCH0R2 = 0x%02x\n", c0drb[2]);
-	i82975x_printk(KERN_INFO, "DRBCH0R3 = 0x%02x\n", c0drb[3]);
-	i82975x_printk(KERN_INFO, "DRBCH1R0 = 0x%02x\n", c1drb[0]);
-	i82975x_printk(KERN_INFO, "DRBCH1R1 = 0x%02x\n", c1drb[1]);
-	i82975x_printk(KERN_INFO, "DRBCH1R2 = 0x%02x\n", c1drb[2]);
-	i82975x_printk(KERN_INFO, "DRBCH1R3 = 0x%02x\n", c1drb[3]);
-
-	i82975x_printk(KERN_INFO, "DRC_CH0 = %0x, %s\n", drc[0],
+		       mchbar, pvt->mch_window);
+
+	for (row = 0; row < DIMMS_PER_CHANNEL; row++) {
+		if (row)
+			/* Only show if at least one bank is filled */
+			if ((pvt->drb[row][0] == pvt->drb[row-1][0]) &&
+			    (pvt->drb[row][1] == pvt->drb[row-1][1]))
+				continue;
+
+		i82975x_printk(KERN_INFO,
+			       "DRAM%i Rank Boundary Address: Channel A: 0x%08x; Channel B: 0x%08x\n",
+			       row,
+			       pvt->drb[row][0],
+			       pvt->drb[row][1]);
+	}
+
+	i82975x_printk(KERN_INFO, "DRAM Controller mode Channel A: = 0x%08x (%s); Channel B: 0x%08x (%s)\n",
+		       drc[0],
 		       ((drc[0] >> 21) & 3) == 1 ?
-				"ECC enabled" : "ECC disabled");
-	i82975x_printk(KERN_INFO, "DRC_CH1 = %0x, %s\n", drc[1],
+		       "ECC enabled" : "ECC disabled",
+		       drc[1],
 		       ((drc[1] >> 21) & 3) == 1 ?
 		       "ECC enabled" : "ECC disabled");
 
-	i82975x_printk(KERN_INFO, "C0 BNKARC = %0x\n",
-		readw(mch_window + I82975X_C0BNKARC));
-	i82975x_printk(KERN_INFO, "C1 BNKARC = %0x\n",
-		readw(mch_window + I82975X_C1BNKARC));
-
-	dtreg[0] = readl(mch_window + 0x114);
-	dtreg[1] = readl(mch_window + 0x194);
-	i82975x_printk(KERN_INFO,
-		"DRAM Timings :  Ch0    Ch1\n"
-		"                RAS Active Min = %d     %d\n"
-		"                CAS latency    =  %d      %d\n"
-		"                RAS to CAS     =  %d      %d\n"
-		"                RAS precharge  =  %d      %d\n",
-		(dtreg[0] >> 19 ) & 0x0f,
-		(dtreg[1] >> 19) & 0x0f,
-		caslats[(dtreg[0] >> 8) & 0x03],
-		caslats[(dtreg[1] >> 8) & 0x03],
-		((dtreg[0] >> 4) & 0x07) + 2,
-		((dtreg[1] >> 4) & 0x07) + 2,
+	i82975x_printk(KERN_INFO, "Bank Architecture Channel A: 0x%08x, Channel B: 0x%08x\n",
+		       readw(pvt->mch_window + I82975X_C0BNKARC),
+		       readw(pvt->mch_window + I82975X_C1BNKARC));
+
+	dtreg[0] = readl(pvt->mch_window + I82975X_C0DRT1);
+	dtreg[1] = readl(pvt->mch_window + I82975X_C1DRT1);
+	i82975x_printk(KERN_INFO, "DRAM Timings :      ChA    ChB\n");
+	i82975x_printk(KERN_INFO, "  RAS Active Min =  %2d      %2d\n",
+		       (dtreg[0] >> 19 ) & 0x0f,(dtreg[1] >> 19) & 0x0f);
+	i82975x_printk(KERN_INFO, "  CAS latency    =  %2d      %2d\n",
+		       caslats[(dtreg[0] >> 8) & 0x03],
+		       caslats[(dtreg[1] >> 8) & 0x03]);
+	i82975x_printk(KERN_INFO, "  RAS to CAS     =  %2d      %2d\n",
+		       ((dtreg[0] >> 4) & 0x07) + 2,
+		       ((dtreg[1] >> 4) & 0x07) + 2);
+	i82975x_printk(KERN_INFO, "  RAS precharge  =  %2d      %2d\n",
 		(dtreg[0] & 0x07) + 2,
-		(dtreg[1] & 0x07) + 2
-	);
+		(dtreg[1] & 0x07) + 2);
 #endif
 }
 
@@ -509,12 +593,10 @@ static int i82975x_probe1(struct pci_dev *pdev, int dev_idx)
 	int rc = -ENODEV;
 	struct mem_ctl_info *mci;
 	struct edac_mc_layer layers[2];
-	struct i82975x_pvt *pvt;
-	void __iomem *mch_window;
+	struct i82975x_pvt tmp_pvt, *pvt;
 	u32 mchbar;
 	u32 drc[2];
 	struct i82975x_error_info discard;
-	int	chans;
 
 	edac_dbg(0, "\n");
 
@@ -524,26 +606,35 @@ static int i82975x_probe1(struct pci_dev *pdev, int dev_idx)
 		goto fail0;
 	}
 	mchbar &= 0xffffc000;	/* bits 31:14 used for 16K window */
-	mch_window = ioremap_nocache(mchbar, 0x1000);
+	tmp_pvt.mch_window = ioremap_nocache(mchbar, 0x1000);
+	if (!tmp_pvt.mch_window) {
+		i82975x_printk(KERN_ERR, "Couldn't map MCHBAR registers.\n");
+		rc = -ENOMEM;
+		goto fail0;
+	}
 
-	drc[0] = readl(mch_window + I82975X_DRC_CH0M0);
-	drc[1] = readl(mch_window + I82975X_DRC_CH1M0);
+	drc[0] = readl(tmp_pvt.mch_window + I82975X_DRC_CH0M0);
+	drc[1] = readl(tmp_pvt.mch_window + I82975X_DRC_CH1M0);
+
+	detect_memory_style(&tmp_pvt);
+	if (!tmp_pvt.num_channels) {
+		edac_dbg(3, "No memories installed? This shouldn't be running!\n");
+		goto fail0;
+	}
 
-	i82975x_print_dram_config(mch_window, mchbar, drc);
+	i82975x_print_dram_config(&tmp_pvt, mchbar, drc);
 
 	if (!(((drc[0] >> 21) & 3) == 1 || ((drc[1] >> 21) & 3) == 1)) {
 		i82975x_printk(KERN_INFO, "ECC disabled on both channels.\n");
 		goto fail1;
 	}
 
-	chans = dual_channel_active(mch_window) + 1;
-
 	/* assuming only one controller, index thus is 0 */
 	layers[0].type = EDAC_MC_LAYER_CHIP_SELECT;
-	layers[0].size = I82975X_NR_DIMMS;
+	layers[0].size = DIMMS_PER_CHANNEL;
 	layers[0].is_virt_csrow = true;
 	layers[1].type = EDAC_MC_LAYER_CHANNEL;
-	layers[1].size = I82975X_NR_CSROWS(chans);
+	layers[1].size = tmp_pvt.num_channels;
 	layers[1].is_virt_csrow = false;
 	mci = edac_mc_alloc(0, ARRAY_SIZE(layers), layers, sizeof(*pvt));
 	if (!mci) {
@@ -562,10 +653,12 @@ static int i82975x_probe1(struct pci_dev *pdev, int dev_idx)
 	mci->dev_name = pci_name(pdev);
 	mci->edac_check = i82975x_check;
 	mci->ctl_page_to_phys = NULL;
+
 	edac_dbg(3, "init pvt\n");
 	pvt = (struct i82975x_pvt *) mci->pvt_info;
-	pvt->mch_window = mch_window;
-	i82975x_init_csrows(mci, pdev, mch_window);
+	*pvt = tmp_pvt;
+
+	i82975x_init_csrows(mci, pvt, pdev);
 	mci->scrub_mode = SCRUB_HW_SRC;
 	i82975x_get_error_info(mci, &discard);  /* clear counters */
 
@@ -583,7 +676,7 @@ fail2:
 	edac_mc_free(mci);
 
 fail1:
-	iounmap(mch_window);
+	iounmap(tmp_pvt.mch_window);
 fail0:
 	return rc;
 }