MIPS: Add hook to get C0 performance counter interrupt

The hardware perf event driver and oprofile interpret the global
cp0_perfcount_irq differently: in the hardware perf event driver
it is an offset from MIPS_CPU_IRQ_BASE and in oprofile it is the
actual IRQ number.  This still works most of the time since
MIPS_CPU_IRQ_BASE is usually 0, but is clearly wrong.  Since the
performance counter interrupt may vary from platform to platform
like the C0 timer interrupt, add the optional get_c0_perfcount_int
hook which returns the IRQ number of the performance counter.
The hook should return < 0 if the performance counter interrupt is
shared with the timer.  If the hook is not present, the CPU vector
reported in C0_IntCtl (cp0_perfcount_irq) is used.

Signed-off-by: Andrew Bresticker <abrestic@chromium.org>
Reviewed-by: Qais Yousef <qais.yousef@imgtec.com>
Tested-by: Qais Yousef <qais.yousef@imgtec.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Andrew Bresticker <abrestic@chromium.org>
Cc: Jeffrey Deans <jeffrey.deans@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Qais Yousef <qais.yousef@imgtec.com>
Cc: Jonas Gorski <jogo@openwrt.org>
Cc: John Crispin <blogic@openwrt.org>
Cc: David Daney <ddaney.cavm@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7805/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 7 insertions, 1 deletions

diff --git a/arch/mips/lantiq/irq.c b/arch/mips/lantiq/irq.c
index 030568a70ac4..21c38eee0a81 100644
--- a/arch/mips/lantiq/irq.c
+++ b/arch/mips/lantiq/irq.c
@@ -70,6 +70,7 @@ static struct resource ltq_eiu_irq[MAX_EIU];
 static void __iomem *ltq_icu_membase[MAX_IM];
 static void __iomem *ltq_eiu_membase;
 static struct irq_domain *ltq_domain;
+static int ltq_perfcount_irq;
 
 int ltq_eiu_get_irq(int exin)
 {
@@ -449,7 +450,7 @@ int __init icu_of_init(struct device_node *node, struct device_node *parent)
 #endif
 
         /* tell oprofile which irq to use */
-        cp0_perfcount_irq = irq_create_mapping(ltq_domain, LTQ_PERF_IRQ);
+        ltq_perfcount_irq = irq_create_mapping(ltq_domain, LTQ_PERF_IRQ);
 
         /*
          * if the timer irq is not one of the mips irqs we need to
@@ -461,6 +462,11 @@ int __init icu_of_init(struct device_node *node, struct device_node *parent)
         return 0;
 }
 
+int get_c0_perfcount_int(void)
+{
+        return ltq_perfcount_irq;
+}
+
 unsigned int get_c0_compare_int(void)
 {
         return MIPS_CPU_TIMER_IRQ;