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/ralink/irq.c b/arch/mips/ralink/irq.c
index 0495011a19df..7634dcd88766 100644
--- a/arch/mips/ralink/irq.c
+++ b/arch/mips/ralink/irq.c
@@ -45,6 +45,7 @@
 #define RALINK_INTC_IRQ_PERFC   (RALINK_INTC_IRQ_BASE + 9)
 
 static void __iomem *rt_intc_membase;
+static int rt_perfcount_irq;
 
 static inline void rt_intc_w32(u32 val, unsigned reg)
 {
@@ -73,6 +74,11 @@ static struct irq_chip ralink_intc_irq_chip = {
         .irq_mask_ack   = ralink_intc_irq_mask,
 };
 
+int get_c0_perfcount_int(void)
+{
+        return rt_perfcount_irq;
+}
+
 unsigned int get_c0_compare_int(void)
 {
         return CP0_LEGACY_COMPARE_IRQ;
@@ -167,7 +173,7 @@ static int __init intc_of_init(struct device_node *node,
         irq_set_handler_data(irq, domain);
 
         /* tell the kernel which irq is used for performance monitoring */
-        cp0_perfcount_irq = irq_create_mapping(domain, 9);
+        rt_perfcount_irq = irq_create_mapping(domain, 9);
 
         return 0;
 }