[AVR32] NMI debugging

Change the NMI handler to use the die notifier chain to signal anyone
who cares. Add a simple "nmi debugger" which hooks into this chain and
that may dump registers, task state, etc. when it happens.

Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>

2 files changed, 33 insertions, 7 deletions

diff --git a/arch/avr32/mach-at32ap/at32ap700x.c b/arch/avr32/mach-at32ap/at32ap700x.c
index 9386e1f82fb8..14e61f05e1f6 100644
--- a/arch/avr32/mach-at32ap/at32ap700x.c
+++ b/arch/avr32/mach-at32ap/at32ap700x.c
@@ -13,6 +13,7 @@
 #include <linux/spi/spi.h>
 
 #include <asm/io.h>
+#include <asm/irq.h>
 
 #include <asm/arch/at32ap700x.h>
 #include <asm/arch/board.h>
diff --git a/arch/avr32/mach-at32ap/extint.c b/arch/avr32/mach-at32ap/extint.c
index f5bfd4c81fe7..e108e7bba8c0 100644
--- a/arch/avr32/mach-at32ap/extint.c
+++ b/arch/avr32/mach-at32ap/extint.c
@@ -26,16 +26,10 @@
 #define EIC_MODE                                0x0014
 #define EIC_EDGE                                0x0018
 #define EIC_LEVEL                               0x001c
-#define EIC_TEST                                0x0020
 #define EIC_NMIC                                0x0024
 
-/* Bitfields in TEST */
-#define EIC_TESTEN_OFFSET                       31
-#define EIC_TESTEN_SIZE                         1
-
 /* Bitfields in NMIC */
-#define EIC_EN_OFFSET                           0
-#define EIC_EN_SIZE                             1
+#define EIC_NMIC_ENABLE                         (1 << 0)
 
 /* Bit manipulation macros */
 #define EIC_BIT(name)                                   \
@@ -63,6 +57,9 @@ struct eic {
         unsigned int first_irq;
 };
 
+static struct eic *nmi_eic;
+static bool nmi_enabled;
+
 static void eic_ack_irq(unsigned int irq)
 {
         struct eic *eic = get_irq_chip_data(irq);
@@ -174,6 +171,24 @@ static void demux_eic_irq(unsigned int irq, struct irq_desc *desc)
         }
 }
 
+int nmi_enable(void)
+{
+        nmi_enabled = true;
+
+        if (nmi_eic)
+                eic_writel(nmi_eic, NMIC, EIC_NMIC_ENABLE);
+
+        return 0;
+}
+
+void nmi_disable(void)
+{
+        if (nmi_eic)
+                eic_writel(nmi_eic, NMIC, 0);
+
+        nmi_enabled = false;
+}
+
 static int __init eic_probe(struct platform_device *pdev)
 {
         struct eic *eic;
@@ -230,6 +245,16 @@ static int __init eic_probe(struct platform_device *pdev)
         set_irq_chained_handler(int_irq, demux_eic_irq);
         set_irq_data(int_irq, eic);
 
+        if (pdev->id == 0) {
+                nmi_eic = eic;
+                if (nmi_enabled)
+                        /*
+                         * Someone tried to enable NMI before we were
+                         * ready. Do it now.
+                         */
+                        nmi_enable();
+        }
+
         dev_info(&pdev->dev,
                  "External Interrupt Controller at 0x%p, IRQ %u\n",
                  eic->regs, int_irq);