bus: brcmstb_gisb: add notifier handling

Check for GISB arbitration errors through a chained notifier
when a process dies or a kernel panic occurs.  This allows a
meaningful GISB diagnostic message to occur along with other
diagnostic information from the event.

Signed-off-by: Doug Berger <opendmb@gmail.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>

diff --git a/drivers/bus/brcmstb_gisb.c b/drivers/bus/brcmstb_gisb.c
index 017c37b..a2e1c5c 100644 (file)
--- a/drivers/bus/brcmstb_gisb.c
+++ b/drivers/bus/brcmstb_gisb.c
@@ -24,6 +24,9 @@
 #include <linux/of.h>
 #include <linux/bitops.h>
 #include <linux/pm.h>
+#include <linux/kernel.h>
+#include <linux/kdebug.h>
+#include <linux/notifier.h>
 
 #ifdef CONFIG_ARM
 #include <asm/bug.h>
@@ -283,6 +286,36 @@ static irqreturn_t brcmstb_gisb_tea_handler(int irq, void *dev_id)
        return IRQ_HANDLED;
 }
 
+/*
+ * Dump out gisb errors on die or panic.
+ */
+static int dump_gisb_error(struct notifier_block *self, unsigned long v,
+                          void *p);
+
+static struct notifier_block gisb_die_notifier = {
+       .notifier_call = dump_gisb_error,
+};
+
+static struct notifier_block gisb_panic_notifier = {
+       .notifier_call = dump_gisb_error,
+};
+
+static int dump_gisb_error(struct notifier_block *self, unsigned long v,
+                          void *p)
+{
+       struct brcmstb_gisb_arb_device *gdev;
+       const char *reason = "panic";
+
+       if (self == &gisb_die_notifier)
+               reason = "die";
+
+       /* iterate over each GISB arb registered handlers */
+       list_for_each_entry(gdev, &brcmstb_gisb_arb_device_list, next)
+               brcmstb_gisb_arb_decode_addr(gdev, reason);
+
+       return NOTIFY_DONE;
+}
+
 static DEVICE_ATTR(gisb_arb_timeout, S_IWUSR | S_IRUGO,
                gisb_arb_get_timeout, gisb_arb_set_timeout);
 
@@ -390,6 +423,12 @@ static int __init brcmstb_gisb_arb_probe(struct platform_device *pdev)
        board_be_handler = brcmstb_bus_error_handler;
 #endif
 
+       if (list_is_singular(&brcmstb_gisb_arb_device_list)) {
+               register_die_notifier(&gisb_die_notifier);
+               atomic_notifier_chain_register(&panic_notifier_list,
+                                              &gisb_panic_notifier);
+       }
+
        dev_info(&pdev->dev, "registered mem: %p, irqs: %d, %d\n",
                        gdev->base, timeout_irq, tea_irq);