[PATCH 2/9] MIPS: Read CPU IRQ line that FDC to routed to

[James Hogan <james.hogan@imgtec.com>]

Read the CPU IRQ line reportedly used for the Fast Debug Channel (FDC)
interrupt from the IntCtl register and store it in cp0_fdc_irq where
platform implementations of the new weak platform function
get_c0_fdc_int() can refer to it.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
---
 arch/mips/include/asm/irq.h |  3 +++
 arch/mips/kernel/traps.c    | 11 +++++++++++
 2 files changed, 14 insertions(+)

diff --git a/arch/mips/include/asm/irq.h b/arch/mips/include/asm/irq.h
index 5a4e1bb8fb1b..f0db99f8defe 100644
--- a/arch/mips/include/asm/irq.h
+++ b/arch/mips/include/asm/irq.h
@@ -47,6 +47,9 @@ extern void free_irqno(unsigned int irq);
 extern int cp0_compare_irq;
 extern int cp0_compare_irq_shift;
 extern int cp0_perfcount_irq;
+extern int cp0_fdc_irq;
+
+extern int __weak get_c0_fdc_int(void);
 
 void arch_trigger_all_cpu_backtrace(bool);
 #define arch_trigger_all_cpu_backtrace arch_trigger_all_cpu_backtrace
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 9c109fd8ba99..290da81c0532 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -1920,6 +1920,12 @@ int cp0_compare_irq_shift;
 int cp0_perfcount_irq;
 EXPORT_SYMBOL_GPL(cp0_perfcount_irq);
 
+/*
+ * Fast debug channel IRQ or -1 if not present
+ */
+int cp0_fdc_irq;
+EXPORT_SYMBOL_GPL(cp0_fdc_irq);
+
 static int noulri;
 
 static int __init ulri_disable(char *s)
@@ -2001,15 +2007,20 @@ void per_cpu_trap_init(bool is_boot_cpu)
 	 *
 	 *  o read IntCtl.IPTI to determine the timer interrupt
 	 *  o read IntCtl.IPPCI to determine the performance counter interrupt
+	 *  o read IntCtl.IPFDC to determine the fast debug channel interrupt
 	 */
 	if (cpu_has_mips_r2) {
 		cp0_compare_irq_shift = CAUSEB_TI - CAUSEB_IP;
 		cp0_compare_irq = (read_c0_intctl() >> INTCTLB_IPTI) & 7;
 		cp0_perfcount_irq = (read_c0_intctl() >> INTCTLB_IPPCI) & 7;
+		cp0_fdc_irq = (read_c0_intctl() >> INTCTLB_IPFDC) & 7;
+		if (!cp0_fdc_irq)
+			cp0_fdc_irq = -1;
 	} else {
 		cp0_compare_irq = CP0_LEGACY_COMPARE_IRQ;
 		cp0_compare_irq_shift = CP0_LEGACY_PERFCNT_IRQ;
 		cp0_perfcount_irq = -1;
+		cp0_fdc_irq = -1;
 	}
 
 	if (!cpu_data[cpu].asid_cache)
-- 
2.0.5