i7core_edac: Add a memory check routine, based on device 3 function 4

This function appears only on Xeon 5500 datasheet. Yet, testing with a
Xeon 3503 showed that this is also implemented on other Nehalem
processors.

At the first read, MC_TEST_ERR_RCV1 and MC_TEST_ERR_RCV0 can contain any
value. Modify CE error logic to update the error count only after the
second read.

An alternative approach would be to do a write at rcv0 and rcv1
registers, but it seemed better to keep they untouched, since BIOS might
eventually assume that they are exclusive for their usage.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 108 insertions, 7 deletions

diff --git a/drivers/edac/i7core_edac.c b/drivers/edac/i7core_edac.c
index 190596af601a..b5dbc2b83961 100644
--- a/drivers/edac/i7core_edac.c
+++ b/drivers/edac/i7core_edac.c
@@ -62,6 +62,18 @@
 #define MC_STATUS       0x4c
 #define MC_MAX_DOD      0x64
 
+/*
+ * OFFSETS for Device 3 Function 4, as inicated on Xeon 5500 datasheet:
+ * http://www.arrownac.com/manufacturers/intel/s/nehalem/5500-datasheet-v2.pdf
+ */
+
+#define MC_TEST_ERR_RCV1        0x60
+  #define DIMM2_COR_ERR(r)                      ((r) & 0x7fff)
+
+#define MC_TEST_ERR_RCV0        0x64
+  #define DIMM1_COR_ERR(r)                      (((r) >> 16) & 0x7fff)
+  #define DIMM0_COR_ERR(r)                      ((r) & 0x7fff)
+
         /* OFFSETS for Devices 4,5 and 6 Function 0 */
 
 #define MC_CHANNEL_DIMM_INIT_PARAMS 0x58
@@ -136,8 +148,9 @@
  */
 
 #define NUM_CHANS 3
-#define NUM_MCR_FUNCS  4
-#define NUM_CHAN_FUNCS 3
+#define MAX_DIMMS 3             /* Max DIMMS per channel */
+#define MAX_MCR_FUNC  4
+#define MAX_CHAN_FUNC 3
 
 struct i7core_info {
         u32     mc_control;
@@ -159,8 +172,8 @@ struct i7core_inject {
 };
 
 struct i7core_channel {
-        u32 ranks;
-        u32 dimms;
+        u32             ranks;
+        u32             dimms;
 };
 
 struct pci_id_descr {
@@ -171,11 +184,16 @@ struct pci_id_descr {
 };
 
 struct i7core_pvt {
-        struct pci_dev          *pci_mcr[NUM_MCR_FUNCS];
-        struct pci_dev          *pci_ch[NUM_CHANS][NUM_CHAN_FUNCS];
+        struct pci_dev          *pci_mcr[MAX_MCR_FUNC + 1];
+        struct pci_dev          *pci_ch[NUM_CHANS][MAX_CHAN_FUNC + 1];
         struct i7core_info      info;
         struct i7core_inject    inject;
         struct i7core_channel   channel[NUM_CHANS];
+
+        int             ce_count_available;
+        unsigned long   ce_count[MAX_DIMMS];    /* ECC corrected errors counts per dimm */
+        int             last_ce_count[MAX_DIMMS];
+
 };
 
 /* Device name and register DID (Device ID) */
@@ -749,6 +767,19 @@ static ssize_t i7core_inject_enable_show(struct mem_ctl_info *mci,
         return sprintf(data, "%d\n", pvt->inject.enable);
 }
 
+static ssize_t i7core_ce_regs_show(struct mem_ctl_info *mci, char *data)
+{
+        struct i7core_pvt *pvt = mci->pvt_info;
+
+        if (!pvt->ce_count_available)
+                return sprintf(data, "unavailable\n");
+
+        return sprintf(data, "dimm0: %lu\ndimm1: %lu\ndimm2: %lu\n",
+                        pvt->ce_count[0],
+                        pvt->ce_count[1],
+                        pvt->ce_count[2]);
+}
+
 /*
  * Sysfs struct
  */
@@ -789,6 +820,13 @@ static struct mcidev_sysfs_attribute i7core_inj_attrs[] = {
                 },
                 .show  = i7core_inject_enable_show,
                 .store = i7core_inject_enable_store,
+        }, {
+                .attr = {
+                        .name = "corrected_error_counts",
+                        .mode = (S_IRUGO | S_IWUSR)
+                },
+                .show  = i7core_ce_regs_show,
+                .store = NULL,
         },
 };
 
@@ -879,13 +917,76 @@ static int i7core_get_devices(struct mem_ctl_info *mci, struct pci_dev *mcidev)
         return 0;
 }
 
+/****************************************************************************
+                        Error check routines
+ ****************************************************************************/
+
+/* This function is based on the device 3 function 4 registers as described on:
+ * Intel Xeon Processor 5500 Series Datasheet Volume 2
+ *      http://www.intel.com/Assets/PDF/datasheet/321322.pdf
+ * also available at:
+ *      http://www.arrownac.com/manufacturers/intel/s/nehalem/5500-datasheet-v2.pdf
+ */
+static void check_mc_test_err(struct mem_ctl_info *mci)
+{
+        struct i7core_pvt *pvt = mci->pvt_info;
+        u32 rcv1, rcv0;
+        int new0, new1, new2;
+
+        if (!pvt->pci_mcr[4]) {
+                debugf0("%s MCR registers not found\n",__func__);
+                return;
+        }
+
+        /* Corrected error reads */
+        pci_read_config_dword(pvt->pci_mcr[4], MC_TEST_ERR_RCV1, &rcv1);
+        pci_read_config_dword(pvt->pci_mcr[4], MC_TEST_ERR_RCV0, &rcv0);
+
+        /* Store the new values */
+        new2 = DIMM2_COR_ERR(rcv1);
+        new1 = DIMM1_COR_ERR(rcv0);
+        new0 = DIMM0_COR_ERR(rcv0);
+
+        debugf2("%s CE rcv1=0x%08x rcv0=0x%08x, %d %d %d\n",
+                (pvt->ce_count_available ? "UPDATE" : "READ"),
+                rcv1, rcv0, new0, new1, new2);
+
+        /* Updates CE counters if it is not the first time here */
+        if (pvt->ce_count_available) {
+                /* Updates CE counters */
+                int add0, add1, add2;
+
+                add2 = new2 - pvt->last_ce_count[2];
+                add1 = new1 - pvt->last_ce_count[1];
+                add0 = new0 - pvt->last_ce_count[0];
+
+                if (add2 < 0)
+                        add2 += 0x7fff;
+                pvt->ce_count[2] += add2;
+
+                if (add1 < 0)
+                        add1 += 0x7fff;
+                pvt->ce_count[1] += add1;
+
+                if (add0 < 0)
+                        add0 += 0x7fff;
+                pvt->ce_count[0] += add0;
+        } else
+                pvt->ce_count_available = 1;
+
+        /* Store the new values */
+        pvt->last_ce_count[2] = new2;
+        pvt->last_ce_count[1] = new1;
+        pvt->last_ce_count[0] = new0;
+}
+
 /*
  *      i7core_check_error      Retrieve and process errors reported by the
  *                              hardware. Called by the Core module.
  */
 static void i7core_check_error(struct mem_ctl_info *mci)
 {
-        /* FIXME: need a real code here */
+        check_mc_test_err(mci);
 }
 
 /*