amd64_edac: add memory scrubber interface

Borislav:
- fix/cleanup comments
- fix function return value patterns
- cleanup debug calls

Reviewed-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: Doug Thompson <dougthompson@xmission.com>
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>

diff --git a/drivers/edac/amd64_edac.c b/drivers/edac/amd64_edac.c
new file mode 100644 (file)
index 0000000..6876d43
--- /dev/null
+++ b/drivers/edac/amd64_edac.c
@@ -0,0 +1,130 @@
+#include "amd64_edac.h"
+
+static struct edac_pci_ctl_info *amd64_ctl_pci;
+
+static int report_gart_errors;
+module_param(report_gart_errors, int, 0644);
+
+/*
+ * Set by command line parameter. If BIOS has enabled the ECC, this override is
+ * cleared to prevent re-enabling the hardware by this driver.
+ */
+static int ecc_enable_override;
+module_param(ecc_enable_override, int, 0644);
+
+/* Lookup table for all possible MC control instances */
+struct amd64_pvt;
+static struct mem_ctl_info *mci_lookup[MAX_NUMNODES];
+static struct amd64_pvt *pvt_lookup[MAX_NUMNODES];
+
+/*
+ * Memory scrubber control interface. For K8, memory scrubbing is handled by
+ * hardware and can involve L2 cache, dcache as well as the main memory. With
+ * F10, this is extended to L3 cache scrubbing on CPU models sporting that
+ * functionality.
+ *
+ * This causes the "units" for the scrubbing speed to vary from 64 byte blocks
+ * (dram) over to cache lines. This is nasty, so we will use bandwidth in
+ * bytes/sec for the setting.
+ *
+ * Currently, we only do dram scrubbing. If the scrubbing is done in software on
+ * other archs, we might not have access to the caches directly.
+ */
+
+/*
+ * scan the scrub rate mapping table for a close or matching bandwidth value to
+ * issue. If requested is too big, then use last maximum value found.
+ */
+static int amd64_search_set_scrub_rate(struct pci_dev *ctl, u32 new_bw,
+                                      u32 min_scrubrate)
+{
+       u32 scrubval;
+       int i;
+
+       /*
+        * map the configured rate (new_bw) to a value specific to the AMD64
+        * memory controller and apply to register. Search for the first
+        * bandwidth entry that is greater or equal than the setting requested
+        * and program that. If at last entry, turn off DRAM scrubbing.
+        */
+       for (i = 0; i < ARRAY_SIZE(scrubrates); i++) {
+               /*
+                * skip scrub rates which aren't recommended
+                * (see F10 BKDG, F3x58)
+                */
+               if (scrubrates[i].scrubval < min_scrubrate)
+                       continue;
+
+               if (scrubrates[i].bandwidth <= new_bw)
+                       break;
+
+               /*
+                * if no suitable bandwidth found, turn off DRAM scrubbing
+                * entirely by falling back to the last element in the
+                * scrubrates array.
+                */
+       }
+
+       scrubval = scrubrates[i].scrubval;
+       if (scrubval)
+               edac_printk(KERN_DEBUG, EDAC_MC,
+                           "Setting scrub rate bandwidth: %u\n",
+                           scrubrates[i].bandwidth);
+       else
+               edac_printk(KERN_DEBUG, EDAC_MC, "Turning scrubbing off.\n");
+
+       pci_write_bits32(ctl, K8_SCRCTRL, scrubval, 0x001F);
+
+       return 0;
+}
+
+static int amd64_set_scrub_rate(struct mem_ctl_info *mci, u32 *bandwidth)
+{
+       struct amd64_pvt *pvt = mci->pvt_info;
+       u32 min_scrubrate = 0x0;
+
+       switch (boot_cpu_data.x86) {
+       case 0xf:
+               min_scrubrate = K8_MIN_SCRUB_RATE_BITS;
+               break;
+       case 0x10:
+               min_scrubrate = F10_MIN_SCRUB_RATE_BITS;
+               break;
+       case 0x11:
+               min_scrubrate = F11_MIN_SCRUB_RATE_BITS;
+               break;
+
+       default:
+               amd64_printk(KERN_ERR, "Unsupported family!\n");
+               break;
+       }
+       return amd64_search_set_scrub_rate(pvt->misc_f3_ctl, *bandwidth,
+                       min_scrubrate);
+}
+
+static int amd64_get_scrub_rate(struct mem_ctl_info *mci, u32 *bw)
+{
+       struct amd64_pvt *pvt = mci->pvt_info;
+       u32 scrubval = 0;
+       int status = -1, i, ret = 0;
+
+       ret = pci_read_config_dword(pvt->misc_f3_ctl, K8_SCRCTRL, &scrubval);
+       if (ret)
+               debugf0("Reading K8_SCRCTRL failed\n");
+
+       scrubval = scrubval & 0x001F;
+
+       edac_printk(KERN_DEBUG, EDAC_MC,
+                   "pci-read, sdram scrub control value: %d \n", scrubval);
+
+       for (i = 0; ARRAY_SIZE(scrubrates); i++) {
+               if (scrubrates[i].scrubval == scrubval) {
+                       *bw = scrubrates[i].bandwidth;
+                       status = 0;
+                       break;
+               }
+       }
+
+       return status;
+}
+