1 files changed, 64 insertions, 3 deletions

diff --git a/drivers/edac/cpc925_edac.c b/drivers/edac/cpc925_edac.c
index a687a0d16962..a774c0ddaf5b 100644
--- a/drivers/edac/cpc925_edac.c
+++ b/drivers/edac/cpc925_edac.c
@@ -90,6 +90,7 @@ enum apimask_bits {
         ECC_MASK_ENABLE = (APIMASK_ECC_UE_H | APIMASK_ECC_CE_H |
                            APIMASK_ECC_UE_L | APIMASK_ECC_CE_L),
 };
+#define APIMASK_ADI(n)          CPC925_BIT(((n)+1))
 
 /************************************************************
  *      Processor Interface Exception Register (APIEXCP)
@@ -581,16 +582,73 @@ static void cpc925_mc_check(struct mem_ctl_info *mci)
 }
 
 /******************** CPU err device********************************/
+static u32 cpc925_cpu_mask_disabled(void)
+{
+        struct device_node *cpus;
+        struct device_node *cpunode = NULL;
+        static u32 mask = 0;
+
+        /* use cached value if available */
+        if (mask != 0)
+                return mask;
+
+        mask = APIMASK_ADI0 | APIMASK_ADI1;
+
+        cpus = of_find_node_by_path("/cpus");
+        if (cpus == NULL) {
+                cpc925_printk(KERN_DEBUG, "No /cpus node !\n");
+                return 0;
+        }
+
+        while ((cpunode = of_get_next_child(cpus, cpunode)) != NULL) {
+                const u32 *reg = of_get_property(cpunode, "reg", NULL);
+
+                if (strcmp(cpunode->type, "cpu")) {
+                        cpc925_printk(KERN_ERR, "Not a cpu node in /cpus: %s\n", cpunode->name);
+                        continue;
+                }
+
+                if (reg == NULL || *reg > 2) {
+                        cpc925_printk(KERN_ERR, "Bad reg value at %s\n", cpunode->full_name);
+                        continue;
+                }
+
+                mask &= ~APIMASK_ADI(*reg);
+        }
+
+        if (mask != (APIMASK_ADI0 | APIMASK_ADI1)) {
+                /* We assume that each CPU sits on it's own PI and that
+                 * for present CPUs the reg property equals to the PI
+                 * interface id */
+                cpc925_printk(KERN_WARNING,
+                                "Assuming PI id is equal to CPU MPIC id!\n");
+        }
+
+        of_node_put(cpunode);
+        of_node_put(cpus);
+
+        return mask;
+}
+
 /* Enable CPU Errors detection */
 static void cpc925_cpu_init(struct cpc925_dev_info *dev_info)
 {
         u32 apimask;
+        u32 cpumask;
 
         apimask = __raw_readl(dev_info->vbase + REG_APIMASK_OFFSET);
-        if ((apimask & CPU_MASK_ENABLE) == 0) {
-                apimask |= CPU_MASK_ENABLE;
-                __raw_writel(apimask, dev_info->vbase + REG_APIMASK_OFFSET);
+
+        cpumask = cpc925_cpu_mask_disabled();
+        if (apimask & cpumask) {
+                cpc925_printk(KERN_WARNING, "CPU(s) not present, "
+                                "but enabled in APIMASK, disabling\n");
+                apimask &= ~cpumask;
         }
+
+        if ((apimask & CPU_MASK_ENABLE) == 0)
+                apimask |= CPU_MASK_ENABLE;
+
+        __raw_writel(apimask, dev_info->vbase + REG_APIMASK_OFFSET);
 }
 
 /* Disable CPU Errors detection */
@@ -622,6 +680,9 @@ static void cpc925_cpu_check(struct edac_device_ctl_info *edac_dev)
         if ((apiexcp & CPU_EXCP_DETECTED) == 0)
                 return;
 
+        if ((apiexcp & ~cpc925_cpu_mask_disabled()) == 0)
+                return;
+
         apimask = __raw_readl(dev_info->vbase + REG_APIMASK_OFFSET);
         cpc925_printk(KERN_INFO, "Processor Interface Fault\n"
                                  "Processor Interface register dump:\n");