[PATCH 2/2] cpc925_edac: support single-processor configurations

[Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>]

If second CPU is not enabled, CPC925 EDAC driver will spill out warnings
about errors on second Processor Interface. Support masking that out,
by detecting at runtime which CPUs are present in device tree.

Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Cc: Harry Ciao <qingtao.cao@windriver.com>
Cc: Doug Thompson <dougthompson@xmission.com>
---
 drivers/edac/cpc925_edac.c |   45 ++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 45 insertions(+), 0 deletions(-)

diff --git a/drivers/edac/cpc925_edac.c b/drivers/edac/cpc925_edac.c
index 837ad8f..fbb6947 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 +582,57 @@ static void cpc925_mc_check(struct mem_ctl_info *mci)
 }
 
 /******************** CPU err device********************************/
+static u32 cpc925_cpu_getmask(void)
+{
+	struct device_node *cpus;
+	struct device_node *cpunode;
+	static u32 mask = 0;
+
+	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;
+	}
+
+	/* Get first CPU node */
+	for (cpunode = NULL;
+	     (cpunode = of_get_next_child(cpus, cpunode)) != NULL;) {
+		const u32 *reg = of_get_property(cpunode, "reg", NULL);
+
+		cpc925_printk(KERN_ERR, "HERE: %s %p %d %d %d %lx\n", cpunode->type, reg, reg ? *reg : -1, !strcmp(cpunode->type, "cpu"), reg != NULL, APIMASK_ADI(*reg));
+		if (!strcmp(cpunode->type, "cpu") && reg != NULL)
+			mask &= ~APIMASK_ADI(*reg);
+	}
+
+	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_getmask();
+	if (apimask & cpumask) {
+		cpc925_printk(KERN_WARNING, "CPU(s) not present, "
+				"but enabled in APIMASK, disabling\n");
+		apimask &= ~cpumask;
+	}
 }
 
 /* Disable CPU Errors detection */
@@ -622,6 +664,9 @@ static void cpc925_cpu_check(struct edac_device_ctl_info *edac_dev)
 	if ((apiexcp & CPU_EXCP_DETECTED) == 0)
 		return;
 
+	if ((apiexcp & ~cpc925_cpu_getmask()) == 0)
+		return;
+
 	apimask = __raw_readl(dev_info->vbase + REG_APIMASK_OFFSET);
 	cpc925_printk(KERN_INFO, "Processor Interface Fault\n"
 				 "Processor Interface register dump:\n");
-- 
1.7.4.4