i7core_edac: Add scrubbing support

Add scrubbing support to i7core_edac, tested on intel Xeon L5638.

Signed-off-by: Samuel Gabrielsson <samuel.gabrielsson@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 126 insertions, 0 deletions

diff --git a/drivers/edac/i7core_edac.c b/drivers/edac/i7core_edac.c
index c64ba267902f..0c02486cf57a 100644
--- a/drivers/edac/i7core_edac.c
+++ b/drivers/edac/i7core_edac.c
@@ -78,6 +78,8 @@ 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 +100,14 @@ 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 MC_COR_ECC_CNT_0        0x80
 #define MC_COR_ECC_CNT_1        0x84
 #define MC_COR_ECC_CNT_2        0x88
@@ -1901,6 +1911,116 @@ static int i7core_mce_check_error(void *priv, struct mce *mce)
         return 1;
 }
 
+/*
+ * 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;
+        const u32 cache_line_size = 64;
+        const u32 freq_dclk = 800*1000000;
+        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 & ~0x00ffffff);
+
+                /* 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 {
+                /*
+                 * Translate the desired scrub rate to a register value and
+                 * program the cooresponding register value.
+                 */
+                dw_scrub = 0x00ffffff & (cache_line_size * freq_dclk / new_bw);
+
+                /* 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 = 800*1000000;
+        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 &=  0x00ffffff;
+        if (!scrubval)
+                return 0;
+
+        /* Calculate scrub rate value into byte/sec bandwidth */
+        return 0xffffffff & (cache_line_size * freq_dclk / (u64) scrubval);
+}
+
+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)
 {
         pvt->i7core_pci = edac_pci_create_generic_ctl(
@@ -1939,6 +2059,9 @@ 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 scrubrate setting */
+        disable_sdram_scrub_setting(mci);
+
         /* Disable MCE NMI handler */
         edac_mce_unregister(&pvt->edac_mce);
 
@@ -2012,6 +2135,9 @@ 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 */
+        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__