EDAC: Fixup scrubrate manipulation

Make the ->{get|set}_sdram_scrub_rate return the actual scrub rate
bandwidth it succeeded setting and remove superfluous arg pointer used
for that. A negative value returned still means that an error occurred
while setting the scrubrate. Document this for future reference.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>

7 files changed, 52 insertions, 63 deletions

diff --git a/drivers/edac/amd64_edac.c b/drivers/edac/amd64_edac.c
index f621aa8becee..8c176fb8a8fb 100644
--- a/drivers/edac/amd64_edac.c
+++ b/drivers/edac/amd64_edac.c
@@ -77,7 +77,11 @@ static int ddr3_dbam[] = { [0]		= -1,
  *FIXME: Produce a better mapping/linearisation.
  */
 
-struct scrubrate scrubrates[] = {
+
+struct scrubrate {
+       u32 scrubval;           /* bit pattern for scrub rate */
+       u32 bandwidth;          /* bandwidth consumed (bytes/sec) */
+} scrubrates[] = {
         { 0x01, 1600000000UL},
         { 0x02, 800000000UL},
         { 0x03, 400000000UL},
@@ -151,14 +155,12 @@ static int __amd64_set_scrub_rate(struct pci_dev *ctl, u32 new_bw, u32 min_rate)
         }
 
         scrubval = scrubrates[i].scrubval;
-        if (scrubval)
-                amd64_info("Setting scrub rate bandwidth: %u\n",
-                           scrubrates[i].bandwidth);
-        else
-                amd64_info("Turning scrubbing off.\n");
 
         pci_write_bits32(ctl, K8_SCRCTRL, scrubval, 0x001F);
 
+        if (scrubval)
+                return scrubrates[i].bandwidth;
+
         return 0;
 }
 
@@ -169,11 +171,11 @@ static int amd64_set_scrub_rate(struct mem_ctl_info *mci, u32 bw)
         return __amd64_set_scrub_rate(pvt->F3, bw, pvt->min_scrubrate);
 }
 
-static int amd64_get_scrub_rate(struct mem_ctl_info *mci, u32 *bw)
+static int amd64_get_scrub_rate(struct mem_ctl_info *mci)
 {
         struct amd64_pvt *pvt = mci->pvt_info;
         u32 scrubval = 0;
-        int status = -1, i;
+        int i, retval = -EINVAL;
 
         amd64_read_pci_cfg(pvt->F3, K8_SCRCTRL, &scrubval);
 
@@ -183,13 +185,11 @@ static int amd64_get_scrub_rate(struct mem_ctl_info *mci, u32 *bw)
 
         for (i = 0; i < ARRAY_SIZE(scrubrates); i++) {
                 if (scrubrates[i].scrubval == scrubval) {
-                        *bw = scrubrates[i].bandwidth;
-                        status = 0;
+                        retval = scrubrates[i].bandwidth;
                         break;
                 }
         }
-
-        return status;
+        return retval;
 }
 
 /* Map from a CSROW entry to the mask entry that operates on it */
diff --git a/drivers/edac/amd64_edac.h b/drivers/edac/amd64_edac.h
index b76dce96e8e6..613ec72b0f65 100644
--- a/drivers/edac/amd64_edac.h
+++ b/drivers/edac/amd64_edac.h
@@ -482,12 +482,6 @@ struct ecc_settings {
         } flags;
 };
 
-struct scrubrate {
-       u32 scrubval;           /* bit pattern for scrub rate */
-       u32 bandwidth;          /* bandwidth consumed (bytes/sec) */
-};
-
-extern struct scrubrate scrubrates[23];
 extern const char *tt_msgs[4];
 extern const char *ll_msgs[4];
 extern const char *rrrr_msgs[16];
diff --git a/drivers/edac/cpc925_edac.c b/drivers/edac/cpc925_edac.c
index 1609a19df495..b9a781c47e3c 100644
--- a/drivers/edac/cpc925_edac.c
+++ b/drivers/edac/cpc925_edac.c
@@ -818,9 +818,10 @@ static void cpc925_del_edac_devices(void)
 }
 
 /* Convert current back-ground scrub rate into byte/sec bandwith */
-static int cpc925_get_sdram_scrub_rate(struct mem_ctl_info *mci, u32 *bw)
+static int cpc925_get_sdram_scrub_rate(struct mem_ctl_info *mci)
 {
         struct cpc925_mc_pdata *pdata = mci->pvt_info;
+        int bw;
         u32 mscr;
         u8 si;
 
@@ -832,11 +833,11 @@ static int cpc925_get_sdram_scrub_rate(struct mem_ctl_info *mci, u32 *bw)
         if (((mscr & MSCR_SCRUB_MOD_MASK) != MSCR_BACKGR_SCRUB) ||
             (si == 0)) {
                 cpc925_mc_printk(mci, KERN_INFO, "Scrub mode not enabled\n");
-                *bw = 0;
+                bw = 0;
         } else
-                *bw = CPC925_SCRUB_BLOCK_SIZE * 0xFA67 / si;
+                bw = CPC925_SCRUB_BLOCK_SIZE * 0xFA67 / si;
 
-        return 0;
+        return bw;
 }
 
 /* Return 0 for single channel; 1 for dual channel */
diff --git a/drivers/edac/e752x_edac.c b/drivers/edac/e752x_edac.c
index 073f5a06d238..ec302d426589 100644
--- a/drivers/edac/e752x_edac.c
+++ b/drivers/edac/e752x_edac.c
@@ -983,11 +983,11 @@ static int set_sdram_scrub_rate(struct mem_ctl_info *mci, u32 new_bw)
 
         pci_write_config_word(pdev, E752X_MCHSCRB, scrubrates[i].scrubval);
 
-        return 0;
+        return scrubrates[i].bandwidth;
 }
 
 /* Convert current scrub rate value into byte/sec bandwidth */
-static int get_sdram_scrub_rate(struct mem_ctl_info *mci, u32 *bw)
+static int get_sdram_scrub_rate(struct mem_ctl_info *mci)
 {
         const struct scrubrate *scrubrates;
         struct e752x_pvt *pvt = (struct e752x_pvt *) mci->pvt_info;
@@ -1013,10 +1013,8 @@ static int get_sdram_scrub_rate(struct mem_ctl_info *mci, u32 *bw)
                         "Invalid sdram scrub control value: 0x%x\n", scrubval);
                 return -1;
         }
+        return scrubrates[i].bandwidth;
 
-        *bw = scrubrates[i].bandwidth;
-
-        return 0;
 }
 
 /* Return 1 if dual channel mode is active.  Else return 0. */
diff --git a/drivers/edac/edac_core.h b/drivers/edac/edac_core.h
index e8d3dd0b5e9c..ff1eb7bb26c6 100644
--- a/drivers/edac/edac_core.h
+++ b/drivers/edac/edac_core.h
@@ -387,7 +387,7 @@ struct mem_ctl_info {
            representation and converts it to the closest matching
            bandwith in bytes/sec.
          */
-        int (*get_sdram_scrub_rate) (struct mem_ctl_info * mci, u32 * bw);
+        int (*get_sdram_scrub_rate) (struct mem_ctl_info * mci);
 
 
         /* pointer to edac checking routine */
diff --git a/drivers/edac/edac_mc_sysfs.c b/drivers/edac/edac_mc_sysfs.c
index dce61f7ba38b..39d97cfdf58c 100644
--- a/drivers/edac/edac_mc_sysfs.c
+++ b/drivers/edac/edac_mc_sysfs.c
@@ -436,56 +436,55 @@ static ssize_t mci_reset_counters_store(struct mem_ctl_info *mci,
         return count;
 }
 
-/* memory scrubbing */
+/* Memory scrubbing interface:
+ *
+ * A MC driver can limit the scrubbing bandwidth based on the CPU type.
+ * Therefore, ->set_sdram_scrub_rate should be made to return the actual
+ * bandwidth that is accepted or 0 when scrubbing is to be disabled.
+ *
+ * Negative value still means that an error has occurred while setting
+ * the scrub rate.
+ */
 static ssize_t mci_sdram_scrub_rate_store(struct mem_ctl_info *mci,
                                           const char *data, size_t count)
 {
         unsigned long bandwidth = 0;
-        int err;
+        int new_bw = 0;
 
-        if (!mci->set_sdram_scrub_rate) {
-                edac_printk(KERN_WARNING, EDAC_MC,
-                            "Memory scrub rate setting not implemented!\n");
+        if (!mci->set_sdram_scrub_rate)
                 return -EINVAL;
-        }
 
         if (strict_strtoul(data, 10, &bandwidth) < 0)
                 return -EINVAL;
 
-        err = mci->set_sdram_scrub_rate(mci, (u32)bandwidth);
-        if (err) {
-                edac_printk(KERN_DEBUG, EDAC_MC,
-                            "Failed setting scrub rate to %lu\n", bandwidth);
-                return -EINVAL;
-        }
-        else {
-                edac_printk(KERN_DEBUG, EDAC_MC,
-                            "Scrub rate set to: %lu\n", bandwidth);
+        new_bw = mci->set_sdram_scrub_rate(mci, bandwidth);
+        if (new_bw >= 0) {
+                edac_printk(KERN_DEBUG, EDAC_MC, "Scrub rate set to %d\n", new_bw);
                 return count;
         }
+
+        edac_printk(KERN_DEBUG, EDAC_MC, "Error setting scrub rate to: %lu\n", bandwidth);
+        return -EINVAL;
 }
 
+/*
+ * ->get_sdram_scrub_rate() return value semantics same as above.
+ */
 static ssize_t mci_sdram_scrub_rate_show(struct mem_ctl_info *mci, char *data)
 {
-        u32 bandwidth = 0;
-        int err;
+        int bandwidth = 0;
 
-        if (!mci->get_sdram_scrub_rate) {
-                edac_printk(KERN_WARNING, EDAC_MC,
-                            "Memory scrub rate reading not implemented\n");
+        if (!mci->get_sdram_scrub_rate)
                 return -EINVAL;
-        }
 
-        err = mci->get_sdram_scrub_rate(mci, &bandwidth);
-        if (err) {
+        bandwidth = mci->get_sdram_scrub_rate(mci);
+        if (bandwidth < 0) {
                 edac_printk(KERN_DEBUG, EDAC_MC, "Error reading scrub rate\n");
-                return err;
-        }
-        else {
-                edac_printk(KERN_DEBUG, EDAC_MC,
-                            "Read scrub rate: %d\n", bandwidth);
-                return sprintf(data, "%d\n", bandwidth);
+                return bandwidth;
         }
+
+        edac_printk(KERN_DEBUG, EDAC_MC, "Read scrub rate: %d\n", bandwidth);
+        return sprintf(data, "%d\n", bandwidth);
 }
 
 /* default attribute files for the MCI object */
diff --git a/drivers/edac/i5100_edac.c b/drivers/edac/i5100_edac.c
index f459a6c0886b..0448da0af75d 100644
--- a/drivers/edac/i5100_edac.c
+++ b/drivers/edac/i5100_edac.c
@@ -611,20 +611,17 @@ static int i5100_set_scrub_rate(struct mem_ctl_info *mci, u32 bandwidth)
 
         bandwidth = 5900000 * i5100_mc_scrben(dw);
 
-        return 0;
+        return bandwidth;
 }
 
-static int i5100_get_scrub_rate(struct mem_ctl_info *mci,
-                                u32 *bandwidth)
+static int i5100_get_scrub_rate(struct mem_ctl_info *mci)
 {
         struct i5100_priv *priv = mci->pvt_info;
         u32 dw;
 
         pci_read_config_dword(priv->mc, I5100_MC, &dw);
 
-        *bandwidth = 5900000 * i5100_mc_scrben(dw);
-
-        return 0;
+        return 5900000 * i5100_mc_scrben(dw);
 }
 
 static struct pci_dev *pci_get_device_func(unsigned vendor,