1 files changed, 377 insertions, 38 deletions

diff --git a/drivers/edac/i7core_edac.c b/drivers/edac/i7core_edac.c
index f6cf448d69b4..70ad8923f1d7 100644
--- a/drivers/edac/i7core_edac.c
+++ b/drivers/edac/i7core_edac.c
@@ -31,11 +31,13 @@
 #include <linux/pci_ids.h>
 #include <linux/slab.h>
 #include <linux/delay.h>
+#include <linux/dmi.h>
 #include <linux/edac.h>
 #include <linux/mmzone.h>
-#include <linux/edac_mce.h>
 #include <linux/smp.h>
+#include <asm/mce.h>
 #include <asm/processor.h>
+#include <asm/div64.h>
 
 #include "edac_core.h"
 
@@ -78,6 +80,8 @@ MODULE_PARM_DESC(use_pci_fixup, "Enable PCI fixup to seek for hidden devices");
 	/* OFFSETS for Device 0 Function 0 */
 
 #define MC_CFG_CONTROL	0x90
+  #define MC_CFG_UNLOCK		0x02
+  #define MC_CFG_LOCK		0x00
 
 	/* OFFSETS for Device 3 Function 0 */
 
@@ -98,6 +102,15 @@ MODULE_PARM_DESC(use_pci_fixup, "Enable PCI fixup to seek for hidden devices");
   #define DIMM0_COR_ERR(r)			((r) & 0x7fff)
 
 /* OFFSETS for Device 3 Function 2, as inicated on Xeon 5500 datasheet */
+#define MC_SSRCONTROL		0x48
+  #define SSR_MODE_DISABLE	0x00
+  #define SSR_MODE_ENABLE	0x01
+  #define SSR_MODE_MASK		0x03
+
+#define MC_SCRUB_CONTROL	0x4c
+  #define STARTSCRUB		(1 << 24)
+  #define SCRUBINTERVAL_MASK    0xffffff
+
 #define MC_COR_ECC_CNT_0	0x80
 #define MC_COR_ECC_CNT_1	0x84
 #define MC_COR_ECC_CNT_2	0x88
@@ -253,10 +266,7 @@ struct i7core_pvt {
 	unsigned long	rdimm_ce_count[NUM_CHANS][MAX_DIMMS];
 	int		rdimm_last_ce_count[NUM_CHANS][MAX_DIMMS];
 
-	unsigned int	is_registered;
-
-	/* mcelog glue */
-	struct edac_mce		edac_mce;
+	bool		is_registered, enable_scrub;
 
 	/* Fifo double buffers */
 	struct mce		mce_entry[MCE_LOG_LEN];
@@ -268,6 +278,9 @@ struct i7core_pvt {
 	/* Count indicator to show errors not got */
 	unsigned		mce_overrun;
 
+	/* DCLK Frequency used for computing scrub rate */
+	int			dclk_freq;
+
 	/* Struct to control EDAC polling */
 	struct edac_pci_ctl_info *i7core_pci;
 };
@@ -281,8 +294,7 @@ static const struct pci_id_descr pci_dev_descr_i7core_nehalem[] = {
 		/* Memory controller */
 	{ PCI_DESCR(3, 0, PCI_DEVICE_ID_INTEL_I7_MCR)     },
 	{ PCI_DESCR(3, 1, PCI_DEVICE_ID_INTEL_I7_MC_TAD)  },
-
-		/* Exists only for RDIMM */
+			/* Exists only for RDIMM */
 	{ PCI_DESCR(3, 2, PCI_DEVICE_ID_INTEL_I7_MC_RAS), .optional = 1  },
 	{ PCI_DESCR(3, 4, PCI_DEVICE_ID_INTEL_I7_MC_TEST) },
 
@@ -303,6 +315,16 @@ static const struct pci_id_descr pci_dev_descr_i7core_nehalem[] = {
 	{ PCI_DESCR(6, 1, PCI_DEVICE_ID_INTEL_I7_MC_CH2_ADDR) },
 	{ PCI_DESCR(6, 2, PCI_DEVICE_ID_INTEL_I7_MC_CH2_RANK) },
 	{ PCI_DESCR(6, 3, PCI_DEVICE_ID_INTEL_I7_MC_CH2_TC)   },
+
+		/* Generic Non-core registers */
+	/*
+	 * This is the PCI device on i7core and on Xeon 35xx (8086:2c41)
+	 * On Xeon 55xx, however, it has a different id (8086:2c40). So,
+	 * the probing code needs to test for the other address in case of
+	 * failure of this one
+	 */
+	{ PCI_DESCR(0, 0, PCI_DEVICE_ID_INTEL_I7_NONCORE)  },
+
 };
 
 static const struct pci_id_descr pci_dev_descr_lynnfield[] = {
@@ -319,6 +341,12 @@ static const struct pci_id_descr pci_dev_descr_lynnfield[] = {
 	{ PCI_DESCR( 5, 1, PCI_DEVICE_ID_INTEL_LYNNFIELD_MC_CH1_ADDR) },
 	{ PCI_DESCR( 5, 2, PCI_DEVICE_ID_INTEL_LYNNFIELD_MC_CH1_RANK) },
 	{ PCI_DESCR( 5, 3, PCI_DEVICE_ID_INTEL_LYNNFIELD_MC_CH1_TC)   },
+
+	/*
+	 * This is the PCI device has an alternate address on some
+	 * processors like Core i7 860
+	 */
+	{ PCI_DESCR( 0, 0, PCI_DEVICE_ID_INTEL_LYNNFIELD_NONCORE)     },
 };
 
 static const struct pci_id_descr pci_dev_descr_i7core_westmere[] = {
@@ -346,6 +374,10 @@ static const struct pci_id_descr pci_dev_descr_i7core_westmere[] = {
 	{ PCI_DESCR(6, 1, PCI_DEVICE_ID_INTEL_LYNNFIELD_MC_CH2_ADDR_REV2) },
 	{ PCI_DESCR(6, 2, PCI_DEVICE_ID_INTEL_LYNNFIELD_MC_CH2_RANK_REV2) },
 	{ PCI_DESCR(6, 3, PCI_DEVICE_ID_INTEL_LYNNFIELD_MC_CH2_TC_REV2)   },
+
+		/* Generic Non-core registers */
+	{ PCI_DESCR(0, 0, PCI_DEVICE_ID_INTEL_LYNNFIELD_NONCORE_REV2)  },
+
 };
 
 #define PCI_ID_TABLE_ENTRY(A) { .descr=A, .n_devs = ARRAY_SIZE(A) }
@@ -714,6 +746,10 @@ static int get_dimm_config(const struct mem_ctl_info *mci)
 
 			csr->edac_mode = mode;
 			csr->mtype = mtype;
+			snprintf(csr->channels[0].label,
+					sizeof(csr->channels[0].label),
+					"CPU#%uChannel#%u_DIMM#%u",
+					pvt->i7core_dev->socket, i, j);
 
 			csrow++;
 		}
@@ -731,7 +767,7 @@ static int get_dimm_config(const struct mem_ctl_info *mci)
 			debugf1("\t\t%#x\t%#x\t%#x\n",
 				(value[j] >> 27) & 0x1,
 				(value[j] >> 24) & 0x7,
-				(value[j] && ((1 << 24) - 1)));
+				(value[j] & ((1 << 24) - 1)));
 	}
 
 	return 0;
@@ -1324,6 +1360,20 @@ static int i7core_get_onedevice(struct pci_dev **prev,
 	pdev = pci_get_device(PCI_VENDOR_ID_INTEL,
 			      dev_descr->dev_id, *prev);
 
+	/*
+	 * On Xeon 55xx, the Intel Quckpath Arch Generic Non-core regs
+	 * is at addr 8086:2c40, instead of 8086:2c41. So, we need
+	 * to probe for the alternate address in case of failure
+	 */
+	if (dev_descr->dev_id == PCI_DEVICE_ID_INTEL_I7_NONCORE && !pdev)
+		pdev = pci_get_device(PCI_VENDOR_ID_INTEL,
+				      PCI_DEVICE_ID_INTEL_I7_NONCORE_ALT, *prev);
+
+	if (dev_descr->dev_id == PCI_DEVICE_ID_INTEL_LYNNFIELD_NONCORE && !pdev)
+		pdev = pci_get_device(PCI_VENDOR_ID_INTEL,
+				      PCI_DEVICE_ID_INTEL_LYNNFIELD_NONCORE_ALT,
+				      *prev);
+
 	if (!pdev) {
 		if (*prev) {
 			*prev = pdev;
@@ -1444,8 +1494,10 @@ static int mci_bind_devs(struct mem_ctl_info *mci,
 	struct i7core_pvt *pvt = mci->pvt_info;
 	struct pci_dev *pdev;
 	int i, func, slot;
+	char *family;
 
-	pvt->is_registered = 0;
+	pvt->is_registered = false;
+	pvt->enable_scrub  = false;
 	for (i = 0; i < i7core_dev->n_devs; i++) {
 		pdev = i7core_dev->pdev[i];
 		if (!pdev)
@@ -1461,9 +1513,37 @@ static int mci_bind_devs(struct mem_ctl_info *mci,
 			if (unlikely(func > MAX_CHAN_FUNC))
 				goto error;
 			pvt->pci_ch[slot - 4][func] = pdev;
-		} else if (!slot && !func)
+		} else if (!slot && !func) {
 			pvt->pci_noncore = pdev;
-		else
+
+			/* Detect the processor family */
+			switch (pdev->device) {
+			case PCI_DEVICE_ID_INTEL_I7_NONCORE:
+				family = "Xeon 35xx/ i7core";
+				pvt->enable_scrub = false;
+				break;
+			case PCI_DEVICE_ID_INTEL_LYNNFIELD_NONCORE_ALT:
+				family = "i7-800/i5-700";
+				pvt->enable_scrub = false;
+				break;
+			case PCI_DEVICE_ID_INTEL_LYNNFIELD_NONCORE:
+				family = "Xeon 34xx";
+				pvt->enable_scrub = false;
+				break;
+			case PCI_DEVICE_ID_INTEL_I7_NONCORE_ALT:
+				family = "Xeon 55xx";
+				pvt->enable_scrub = true;
+				break;
+			case PCI_DEVICE_ID_INTEL_LYNNFIELD_NONCORE_REV2:
+				family = "Xeon 56xx / i7-900";
+				pvt->enable_scrub = true;
+				break;
+			default:
+				family = "unknown";
+				pvt->enable_scrub = false;
+			}
+			debugf0("Detected a processor type %s\n", family);
+		} else
 			goto error;
 
 		debugf0("Associated fn %d.%d, dev = %p, socket %d\n",
@@ -1472,7 +1552,7 @@ static int mci_bind_devs(struct mem_ctl_info *mci,
 
 		if (PCI_SLOT(pdev->devfn) == 3 &&
 			PCI_FUNC(pdev->devfn) == 2)
-			pvt->is_registered = 1;
+			pvt->is_registered = true;
 	}
 
 	return 0;
@@ -1826,33 +1906,43 @@ check_ce_error:
  * WARNING: As this routine should be called at NMI time, extra care should
  * be taken to avoid deadlocks, and to be as fast as possible.
  */
-static int i7core_mce_check_error(void *priv, struct mce *mce)
+static int i7core_mce_check_error(struct notifier_block *nb, unsigned long val,
+				  void *data)
 {
-	struct mem_ctl_info *mci = priv;
-	struct i7core_pvt *pvt = mci->pvt_info;
+	struct mce *mce = (struct mce *)data;
+	struct i7core_dev *i7_dev;
+	struct mem_ctl_info *mci;
+	struct i7core_pvt *pvt;
+
+	i7_dev = get_i7core_dev(mce->socketid);
+	if (!i7_dev)
+		return NOTIFY_BAD;
+
+	mci = i7_dev->mci;
+	pvt = mci->pvt_info;
 
 	/*
 	 * Just let mcelog handle it if the error is
 	 * outside the memory controller
 	 */
 	if (((mce->status & 0xffff) >> 7) != 1)
-		return 0;
+		return NOTIFY_DONE;
 
 	/* Bank 8 registers are the only ones that we know how to handle */
 	if (mce->bank != 8)
-		return 0;
+		return NOTIFY_DONE;
 
 #ifdef CONFIG_SMP
 	/* Only handle if it is the right mc controller */
-	if (cpu_data(mce->cpu).phys_proc_id != pvt->i7core_dev->socket)
-		return 0;
+	if (mce->socketid != pvt->i7core_dev->socket)
+		return NOTIFY_DONE;
 #endif
 
 	smp_rmb();
 	if ((pvt->mce_out + 1) % MCE_LOG_LEN == pvt->mce_in) {
 		smp_wmb();
 		pvt->mce_overrun++;
-		return 0;
+		return NOTIFY_DONE;
 	}
 
 	/* Copy memory error at the ringbuffer */
@@ -1865,7 +1955,240 @@ static int i7core_mce_check_error(void *priv, struct mce *mce)
 		i7core_check_error(mci);
 
 	/* Advise mcelog that the errors were handled */
-	return 1;
+	return NOTIFY_STOP;
+}
+
+static struct notifier_block i7_mce_dec = {
+	.notifier_call	= i7core_mce_check_error,
+};
+
+struct memdev_dmi_entry {
+	u8 type;
+	u8 length;
+	u16 handle;
+	u16 phys_mem_array_handle;
+	u16 mem_err_info_handle;
+	u16 total_width;
+	u16 data_width;
+	u16 size;
+	u8 form;
+	u8 device_set;
+	u8 device_locator;
+	u8 bank_locator;
+	u8 memory_type;
+	u16 type_detail;
+	u16 speed;
+	u8 manufacturer;
+	u8 serial_number;
+	u8 asset_tag;
+	u8 part_number;
+	u8 attributes;
+	u32 extended_size;
+	u16 conf_mem_clk_speed;
+} __attribute__((__packed__));
+
+
+/*
+ * Decode the DRAM Clock Frequency, be paranoid, make sure that all
+ * memory devices show the same speed, and if they don't then consider
+ * all speeds to be invalid.
+ */
+static void decode_dclk(const struct dmi_header *dh, void *_dclk_freq)
+{
+	int *dclk_freq = _dclk_freq;
+	u16 dmi_mem_clk_speed;
+
+	if (*dclk_freq == -1)
+		return;
+
+	if (dh->type == DMI_ENTRY_MEM_DEVICE) {
+		struct memdev_dmi_entry *memdev_dmi_entry =
+			(struct memdev_dmi_entry *)dh;
+		unsigned long conf_mem_clk_speed_offset =
+			(unsigned long)&memdev_dmi_entry->conf_mem_clk_speed -
+			(unsigned long)&memdev_dmi_entry->type;
+		unsigned long speed_offset =
+			(unsigned long)&memdev_dmi_entry->speed -
+			(unsigned long)&memdev_dmi_entry->type;
+
+		/* Check that a DIMM is present */
+		if (memdev_dmi_entry->size == 0)
+			return;
+
+		/*
+		 * Pick the configured speed if it's available, otherwise
+		 * pick the DIMM speed, or we don't have a speed.
+		 */
+		if (memdev_dmi_entry->length > conf_mem_clk_speed_offset) {
+			dmi_mem_clk_speed =
+				memdev_dmi_entry->conf_mem_clk_speed;
+		} else if (memdev_dmi_entry->length > speed_offset) {
+			dmi_mem_clk_speed = memdev_dmi_entry->speed;
+		} else {
+			*dclk_freq = -1;
+			return;
+		}
+
+		if (*dclk_freq == 0) {
+			/* First pass, speed was 0 */
+			if (dmi_mem_clk_speed > 0) {
+				/* Set speed if a valid speed is read */
+				*dclk_freq = dmi_mem_clk_speed;
+			} else {
+				/* Otherwise we don't have a valid speed */
+				*dclk_freq = -1;
+			}
+		} else if (*dclk_freq > 0 &&
+			   *dclk_freq != dmi_mem_clk_speed) {
+			/*
+			 * If we have a speed, check that all DIMMS are the same
+			 * speed, otherwise set the speed as invalid.
+			 */
+			*dclk_freq = -1;
+		}
+	}
+}
+
+/*
+ * The default DCLK frequency is used as a fallback if we
+ * fail to find anything reliable in the DMI. The value
+ * is taken straight from the datasheet.
+ */
+#define DEFAULT_DCLK_FREQ 800
+
+static int get_dclk_freq(void)
+{
+	int dclk_freq = 0;
+
+	dmi_walk(decode_dclk, (void *)&dclk_freq);
+
+	if (dclk_freq < 1)
+		return DEFAULT_DCLK_FREQ;
+
+	return dclk_freq;
+}
+
+/*
+ * set_sdram_scrub_rate		This routine sets byte/sec bandwidth scrub rate
+ *				to hardware according to SCRUBINTERVAL formula
+ *				found in datasheet.
+ */
+static int set_sdram_scrub_rate(struct mem_ctl_info *mci, u32 new_bw)
+{
+	struct i7core_pvt *pvt = mci->pvt_info;
+	struct pci_dev *pdev;
+	u32 dw_scrub;
+	u32 dw_ssr;
+
+	/* Get data from the MC register, function 2 */
+	pdev = pvt->pci_mcr[2];
+	if (!pdev)
+		return -ENODEV;
+
+	pci_read_config_dword(pdev, MC_SCRUB_CONTROL, &dw_scrub);
+
+	if (new_bw == 0) {
+		/* Prepare to disable petrol scrub */
+		dw_scrub &= ~STARTSCRUB;
+		/* Stop the patrol scrub engine */
+		write_and_test(pdev, MC_SCRUB_CONTROL,
+			       dw_scrub & ~SCRUBINTERVAL_MASK);
+
+		/* Get current status of scrub rate and set bit to disable */
+		pci_read_config_dword(pdev, MC_SSRCONTROL, &dw_ssr);
+		dw_ssr &= ~SSR_MODE_MASK;
+		dw_ssr |= SSR_MODE_DISABLE;
+	} else {
+		const int cache_line_size = 64;
+		const u32 freq_dclk_mhz = pvt->dclk_freq;
+		unsigned long long scrub_interval;
+		/*
+		 * Translate the desired scrub rate to a register value and
+		 * program the corresponding register value.
+		 */
+		scrub_interval = (unsigned long long)freq_dclk_mhz *
+			cache_line_size * 1000000;
+		do_div(scrub_interval, new_bw);
+
+		if (!scrub_interval || scrub_interval > SCRUBINTERVAL_MASK)
+			return -EINVAL;
+
+		dw_scrub = SCRUBINTERVAL_MASK & scrub_interval;
+
+		/* Start the patrol scrub engine */
+		pci_write_config_dword(pdev, MC_SCRUB_CONTROL,
+				       STARTSCRUB | dw_scrub);
+
+		/* Get current status of scrub rate and set bit to enable */
+		pci_read_config_dword(pdev, MC_SSRCONTROL, &dw_ssr);
+		dw_ssr &= ~SSR_MODE_MASK;
+		dw_ssr |= SSR_MODE_ENABLE;
+	}
+	/* Disable or enable scrubbing */
+	pci_write_config_dword(pdev, MC_SSRCONTROL, dw_ssr);
+
+	return new_bw;
+}
+
+/*
+ * get_sdram_scrub_rate		This routine convert current scrub rate value
+ *				into byte/sec bandwidth accourding to
+ *				SCRUBINTERVAL formula found in datasheet.
+ */
+static int get_sdram_scrub_rate(struct mem_ctl_info *mci)
+{
+	struct i7core_pvt *pvt = mci->pvt_info;
+	struct pci_dev *pdev;
+	const u32 cache_line_size = 64;
+	const u32 freq_dclk_mhz = pvt->dclk_freq;
+	unsigned long long scrub_rate;
+	u32 scrubval;
+
+	/* Get data from the MC register, function 2 */
+	pdev = pvt->pci_mcr[2];
+	if (!pdev)
+		return -ENODEV;
+
+	/* Get current scrub control data */
+	pci_read_config_dword(pdev, MC_SCRUB_CONTROL, &scrubval);
+
+	/* Mask highest 8-bits to 0 */
+	scrubval &=  SCRUBINTERVAL_MASK;
+	if (!scrubval)
+		return 0;
+
+	/* Calculate scrub rate value into byte/sec bandwidth */
+	scrub_rate =  (unsigned long long)freq_dclk_mhz *
+		1000000 * cache_line_size;
+	do_div(scrub_rate, scrubval);
+	return (int)scrub_rate;
+}
+
+static void enable_sdram_scrub_setting(struct mem_ctl_info *mci)
+{
+	struct i7core_pvt *pvt = mci->pvt_info;
+	u32 pci_lock;
+
+	/* Unlock writes to pci registers */
+	pci_read_config_dword(pvt->pci_noncore, MC_CFG_CONTROL, &pci_lock);
+	pci_lock &= ~0x3;
+	pci_write_config_dword(pvt->pci_noncore, MC_CFG_CONTROL,
+			       pci_lock | MC_CFG_UNLOCK);
+
+	mci->set_sdram_scrub_rate = set_sdram_scrub_rate;
+	mci->get_sdram_scrub_rate = get_sdram_scrub_rate;
+}
+
+static void disable_sdram_scrub_setting(struct mem_ctl_info *mci)
+{
+	struct i7core_pvt *pvt = mci->pvt_info;
+	u32 pci_lock;
+
+	/* Lock writes to pci registers */
+	pci_read_config_dword(pvt->pci_noncore, MC_CFG_CONTROL, &pci_lock);
+	pci_lock &= ~0x3;
+	pci_write_config_dword(pvt->pci_noncore, MC_CFG_CONTROL,
+			       pci_lock | MC_CFG_LOCK);
 }
 
 static void i7core_pci_ctl_create(struct i7core_pvt *pvt)
@@ -1874,7 +2197,8 @@ static void i7core_pci_ctl_create(struct i7core_pvt *pvt)
 						&pvt->i7core_dev->pdev[0]->dev,
 						EDAC_MOD_STR);
 	if (unlikely(!pvt->i7core_pci))
-		pr_warn("Unable to setup PCI error report via EDAC\n");
+		i7core_printk(KERN_WARNING,
+			      "Unable to setup PCI error report via EDAC\n");
 }
 
 static void i7core_pci_ctl_release(struct i7core_pvt *pvt)
@@ -1906,8 +2230,11 @@ static void i7core_unregister_mci(struct i7core_dev *i7core_dev)
 	debugf0("MC: " __FILE__ ": %s(): mci = %p, dev = %p\n",
 		__func__, mci, &i7core_dev->pdev[0]->dev);
 
-	/* Disable MCE NMI handler */
-	edac_mce_unregister(&pvt->edac_mce);
+	/* Disable scrubrate setting */
+	if (pvt->enable_scrub)
+		disable_sdram_scrub_setting(mci);
+
+	atomic_notifier_chain_unregister(&x86_mce_decoder_chain, &i7_mce_dec);
 
 	/* Disable EDAC polling */
 	i7core_pci_ctl_release(pvt);
@@ -1979,6 +2306,10 @@ static int i7core_register_mci(struct i7core_dev *i7core_dev)
 	/* Set the function pointer to an actual operation function */
 	mci->edac_check = i7core_check_error;
 
+	/* Enable scrubrate setting */
+	if (pvt->enable_scrub)
+		enable_sdram_scrub_setting(mci);
+
 	/* add this new MC control structure to EDAC's list of MCs */
 	if (unlikely(edac_mc_add_mc(mci))) {
 		debugf0("MC: " __FILE__
@@ -2002,21 +2333,13 @@ static int i7core_register_mci(struct i7core_dev *i7core_dev)
 	/* allocating generic PCI control info */
 	i7core_pci_ctl_create(pvt);
 
-	/* Registers on edac_mce in order to receive memory errors */
-	pvt->edac_mce.priv = mci;
-	pvt->edac_mce.check_error = i7core_mce_check_error;
-	rc = edac_mce_register(&pvt->edac_mce);
-	if (unlikely(rc < 0)) {
-		debugf0("MC: " __FILE__
-			": %s(): failed edac_mce_register()\n", __func__);
-		goto fail1;
-	}
+	/* DCLK for scrub rate setting */
+	pvt->dclk_freq = get_dclk_freq();
+
+	atomic_notifier_chain_register(&x86_mce_decoder_chain, &i7_mce_dec);
 
 	return 0;
 
-fail1:
-	i7core_pci_ctl_release(pvt);
-	edac_mc_del_mc(mci->dev);
 fail0:
 	kfree(mci->ctl_name);
 	edac_mc_free(mci);
@@ -2035,7 +2358,7 @@ fail0:
 static int __devinit i7core_probe(struct pci_dev *pdev,
 				  const struct pci_device_id *id)
 {
-	int rc;
+	int rc, count = 0;
 	struct i7core_dev *i7core_dev;
 
 	/* get the pci devices we want to reserve for our use */
@@ -2055,12 +2378,28 @@ static int __devinit i7core_probe(struct pci_dev *pdev,
 		goto fail0;
 
 	list_for_each_entry(i7core_dev, &i7core_edac_list, list) {
+		count++;
 		rc = i7core_register_mci(i7core_dev);
 		if (unlikely(rc < 0))
 			goto fail1;
 	}
 
-	i7core_printk(KERN_INFO, "Driver loaded.\n");
+	/*
+	 * Nehalem-EX uses a different memory controller. However, as the
+	 * memory controller is not visible on some Nehalem/Nehalem-EP, we
+	 * need to indirectly probe via a X58 PCI device. The same devices
+	 * are found on (some) Nehalem-EX. So, on those machines, the
+	 * probe routine needs to return -ENODEV, as the actual Memory
+	 * Controller registers won't be detected.
+	 */
+	if (!count) {
+		rc = -ENODEV;
+		goto fail1;
+	}
+
+	i7core_printk(KERN_INFO,
+		      "Driver loaded, %d memory controller(s) found.\n",
+		      count);
 
 	mutex_unlock(&i7core_edac_lock);
 	return 0;