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>

arch/mips/ath79/irq.c

@@ -359,7 +359,6 @@ void __init arch_init_irq(void)
 		BUG();
 	}
 
-	cp0_perfcount_irq = ATH79_MISC_IRQ(5);
 	mips_cpu_irq_init();
 	ath79_misc_irq_init();
 

arch/mips/ath79/setup.c

@@ -182,6 +182,11 @@ const char *get_system_type(void)
 	return ath79_sys_type;
 }
 
+int get_c0_perfcount_int(void)
+{
+	return ATH79_MISC_IRQ(5);
+}
+
 unsigned int get_c0_compare_int(void)
 {
 	return CP0_LEGACY_COMPARE_IRQ;

arch/mips/include/asm/time.h

@@ -46,6 +46,7 @@ extern unsigned int mips_hpt_frequency;
  * so it lives here.
  */
 extern int (*perf_irq)(void);
+extern int __weak get_c0_perfcount_int(void);
 
 /*
  * Initialize the calling CPU's compare interrupt as clockevent device

arch/mips/kernel/perf_event_mipsxx.c

@@ -1613,22 +1613,13 @@ init_hw_perf_events(void)
 		counters = counters_total_to_per_cpu(counters);
 #endif
 
-#ifdef MSC01E_INT_BASE
-	if (cpu_has_veic) {
-		/*
-		 * Using platform specific interrupt controller defines.
-		 */
-		irq = MSC01E_INT_BASE + MSC01E_INT_PERFCTR;
-	} else {
-#endif
-		if ((cp0_perfcount_irq >= 0) &&
-				(cp0_compare_irq != cp0_perfcount_irq))
-			irq = MIPS_CPU_IRQ_BASE + cp0_perfcount_irq;
-		else
-			irq = -1;
-#ifdef MSC01E_INT_BASE
-	}
-#endif
+	if (get_c0_perfcount_int)
+		irq = get_c0_perfcount_int();
+	else if ((cp0_perfcount_irq >= 0) &&
+		 (cp0_compare_irq != cp0_perfcount_irq))
+		irq = MIPS_CPU_IRQ_BASE + cp0_perfcount_irq;
+	else
+		irq = -1;
 
 	mipspmu.map_raw_event = mipsxx_pmu_map_raw_event;
 

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;

arch/mips/mti-malta/malta-time.c

@@ -121,22 +121,20 @@ void read_persistent_clock(struct timespec *ts)
 	ts->tv_nsec = 0;
 }
 
-static void __init plat_perf_setup(void)
+int get_c0_perfcount_int(void)
 {
-#ifdef MSC01E_INT_BASE
 	if (cpu_has_veic) {
 		set_vi_handler(MSC01E_INT_PERFCTR, mips_perf_dispatch);
 		mips_cpu_perf_irq = MSC01E_INT_BASE + MSC01E_INT_PERFCTR;
-	} else
-#endif
-	if (cp0_perfcount_irq >= 0) {
+	} else if (cp0_perfcount_irq >= 0) {
 		if (cpu_has_vint)
 			set_vi_handler(cp0_perfcount_irq, mips_perf_dispatch);
 		mips_cpu_perf_irq = MIPS_CPU_IRQ_BASE + cp0_perfcount_irq;
-#ifdef CONFIG_SMP
-		irq_set_handler(mips_cpu_perf_irq, handle_percpu_irq);
-#endif
+	} else {
+		mips_cpu_perf_irq = -1;
 	}
+
+	return mips_cpu_perf_irq;
 }
 
 unsigned int get_c0_compare_int(void)
@@ -201,6 +199,4 @@ void __init plat_time_init(void)
 #endif
 	}
 #endif
-
-	plat_perf_setup();
 }

arch/mips/mti-sead3/sead3-time.c

@@ -81,13 +81,16 @@ void read_persistent_clock(struct timespec *ts)
 	ts->tv_nsec = 0;
 }
 
-static void __init plat_perf_setup(void)
+int get_c0_perfcount_int(void)
 {
 	if (cp0_perfcount_irq >= 0) {
 		if (cpu_has_vint)
 			set_vi_handler(cp0_perfcount_irq, mips_perf_dispatch);
 		mips_cpu_perf_irq = MIPS_CPU_IRQ_BASE + cp0_perfcount_irq;
+	} else {
+		mips_cpu_perf_irq = -1;
 	}
+	return mips_cpu_perf_irq;
 }
 
 unsigned int get_c0_compare_int(void)
@@ -108,6 +111,4 @@ void __init plat_time_init(void)
 		(est_freq % 1000000) * 100 / 1000000);
 
 	mips_scroll_message();
-
-	plat_perf_setup();
 }

arch/mips/oprofile/op_model_mipsxx.c

@@ -11,6 +11,7 @@
 #include <linux/interrupt.h>
 #include <linux/smp.h>
 #include <asm/irq_regs.h>
+#include <asm/time.h>
 
 #include "op_impl.h"
 
@@ -35,6 +36,7 @@
 #define M_PERFCTL_COUNT_ALL_THREADS	(1UL	  << 13)
 
 static int (*save_perf_irq)(void);
+static int perfcount_irq;
 
 /*
  * XLR has only one set of counters per core. Designate the
@@ -431,8 +433,16 @@ static int __init mipsxx_init(void)
 	save_perf_irq = perf_irq;
 	perf_irq = mipsxx_perfcount_handler;
 
-	if ((cp0_perfcount_irq >= 0) && (cp0_compare_irq != cp0_perfcount_irq))
-		return request_irq(cp0_perfcount_irq, mipsxx_perfcount_int,
+	if (get_c0_perfcount_int)
+		perfcount_irq = get_c0_perfcount_int();
+	else if ((cp0_perfcount_irq >= 0) &&
+		 (cp0_compare_irq != cp0_perfcount_irq))
+		perfcount_irq = MIPS_CPU_IRQ_BASE + cp0_perfcount_irq;
+	else
+		perfcount_irq = -1;
+
+	if (perfcount_irq >= 0)
+		return request_irq(perfcount_irq, mipsxx_perfcount_int,
 			0, "Perfcounter", save_perf_irq);
 
 	return 0;
@@ -442,8 +452,8 @@ static void mipsxx_exit(void)
 {
 	int counters = op_model_mipsxx_ops.num_counters;
 
-	if ((cp0_perfcount_irq >= 0) && (cp0_compare_irq != cp0_perfcount_irq))
-		free_irq(cp0_perfcount_irq, save_perf_irq);
+	if (perfcount_irq >= 0)
+		free_irq(perfcount_irq, save_perf_irq);
 
 	counters = counters_per_cpu_to_total(counters);
 	on_each_cpu(reset_counters, (void *)(long)counters, 1);

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;
 }