[PATCH 6/6] ARM: versatile: Make able to use UART ports for KGDB FIQ debugger

[Anton Vorontsov]

If enabled, kernel will able to enter KGDB upon serial line activity on
UART ports.

Note that even with this patch and CONFIG_KGDB_FIQ is enabled, you still
need to pass kgdb_fiq.enable=1 kernel command line option, otherwise UART
will behave in a normal way.

By default UART0 is used, but this can be changed via kgdb_fiq.uart_num
kernel command line option.

Signed-off-by: Anton Vorontsov <anton.vorontsov at linaro.org>
---
 arch/arm/mach-versatile/Makefile            |    1 +
 arch/arm/mach-versatile/include/mach/irqs.h |    1 +
 arch/arm/mach-versatile/kgdb_fiq.c          |   40 +++++++++++++++++++++++++++
 3 files changed, 42 insertions(+)
 create mode 100644 arch/arm/mach-versatile/kgdb_fiq.c

diff --git a/arch/arm/mach-versatile/Makefile b/arch/arm/mach-versatile/Makefile
index 81fa3fe..bfd761f 100644
--- a/arch/arm/mach-versatile/Makefile
+++ b/arch/arm/mach-versatile/Makefile
@@ -7,3 +7,4 @@ obj-$(CONFIG_ARCH_VERSATILE_PB)		+= versatile_pb.o
 obj-$(CONFIG_MACH_VERSATILE_AB)		+= versatile_ab.o
 obj-$(CONFIG_MACH_VERSATILE_DT)		+= versatile_dt.o
 obj-$(CONFIG_PCI)			+= pci.o
+obj-$(CONFIG_KGDB_FIQ)			+= kgdb_fiq.o
diff --git a/arch/arm/mach-versatile/include/mach/irqs.h b/arch/arm/mach-versatile/include/mach/irqs.h
index bf44c61..fcd2a95 100644
--- a/arch/arm/mach-versatile/include/mach/irqs.h
+++ b/arch/arm/mach-versatile/include/mach/irqs.h
@@ -26,6 +26,7 @@
  *  held within platform.h
  */
 #define IRQ_VIC_START		0
+#define FIQ_START		IRQ_VIC_START
 #define IRQ_WDOGINT		(IRQ_VIC_START + INT_WDOGINT)
 #define IRQ_SOFTINT		(IRQ_VIC_START + INT_SOFTINT)
 #define IRQ_COMMRx		(IRQ_VIC_START + INT_COMMRx)
diff --git a/arch/arm/mach-versatile/kgdb_fiq.c b/arch/arm/mach-versatile/kgdb_fiq.c
new file mode 100644
index 0000000..c82e8ce
--- /dev/null
+++ b/arch/arm/mach-versatile/kgdb_fiq.c
@@ -0,0 +1,40 @@
+/*
+ * KGDB FIQ entry board/IC support
+ *
+ * Copyright 2012 Linaro Ltd.
+ *		  Anton Vorontsov <anton.vorontsov at linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kgdb.h>
+#include <mach/hardware.h>
+#include <mach/platform.h>
+#include <asm/kgdb.h>
+#include <asm/hardware/vic.h>
+
+static int kgdb_fiq;
+module_param_named(uart_num, kgdb_fiq, int, 0600);
+MODULE_PARM_DESC(uart_num, "UART<number> port to use for KGDB FIQ");
+
+static bool is_kgdb_nmi(void)
+{
+	return vic_is_fiq_rised(kgdb_fiq);
+}
+
+void kgdb_arch_enable_nmi(bool on)
+{
+	vic_fiq_select(kgdb_fiq, on);
+}
+
+static int kgdb_fiq_init(void)
+{
+	kgdb_fiq += INT_UARTINT0;
+	kgdb_register_nmi(is_kgdb_nmi);
+	return 0;
+}
+console_initcall(kgdb_fiq_init);
-- 
1.7.10.4