msm: timer: SMP timer support for msm

The msm provides timer hardware that is private to each core. Each
timer has separate counter and match registers, so we create separate
clock_event_devices for each core. For the global clocksource, use
cpu 0's counter.

Signed-off-by: Jeff Ohlstein <johlstei@codeaurora.org>
Signed-off-by: David Brown <davidb@codeaurora.org>

1 files changed, 102 insertions, 23 deletions

diff --git a/arch/arm/mach-msm/timer.c b/arch/arm/mach-msm/timer.c
index 595be7fea31..c105d28b53e 100644
--- a/arch/arm/mach-msm/timer.c
+++ b/arch/arm/mach-msm/timer.c
@@ -47,6 +47,19 @@ enum {
 
 #define GPT_HZ 32768
 
+enum timer_location {
+	LOCAL_TIMER = 0,
+	GLOBAL_TIMER = 1,
+};
+
+#ifdef MSM_TMR0_BASE
+#define MSM_TMR_GLOBAL		(MSM_TMR0_BASE - MSM_TMR_BASE)
+#else
+#define MSM_TMR_GLOBAL		0
+#endif
+
+#define MSM_GLOBAL_TIMER MSM_CLOCK_DGT
+
 #if defined(CONFIG_ARCH_QSD8X50)
 #define DGT_HZ (19200000 / 4) /* 19.2 MHz / 4 by default */
 #define MSM_DGT_SHIFT (0)
@@ -65,49 +78,67 @@ struct msm_clock {
 	void __iomem                *regbase;
 	uint32_t                    freq;
 	uint32_t                    shift;
+	void __iomem                *global_counter;
+	void __iomem                *local_counter;
+};
+
+enum {
+	MSM_CLOCK_GPT,
+	MSM_CLOCK_DGT,
+	NR_TIMERS,
 };
 
+
+static struct msm_clock msm_clocks[];
+static struct clock_event_device *local_clock_event;
+
 static irqreturn_t msm_timer_interrupt(int irq, void *dev_id)
 {
 	struct clock_event_device *evt = dev_id;
+	if (smp_processor_id() != 0)
+		evt = local_clock_event;
+	if (evt->event_handler == NULL)
+		return IRQ_HANDLED;
 	evt->event_handler(evt);
 	return IRQ_HANDLED;
 }
 
-static cycle_t msm_gpt_read(struct clocksource *cs)
+static cycle_t msm_read_timer_count(struct clocksource *cs)
 {
-	return readl(MSM_GPT_BASE + TIMER_COUNT_VAL);
+	struct msm_clock *clk = container_of(cs, struct msm_clock, clocksource);
+
+	return readl(clk->global_counter);
 }
 
-static cycle_t msm_dgt_read(struct clocksource *cs)
+static struct msm_clock *clockevent_to_clock(struct clock_event_device *evt)
 {
-	return readl(MSM_DGT_BASE + TIMER_COUNT_VAL) >> MSM_DGT_SHIFT;
+#ifdef CONFIG_SMP
+	int i;
+	for (i = 0; i < NR_TIMERS; i++)
+		if (evt == &(msm_clocks[i].clockevent))
+			return &msm_clocks[i];
+	return &msm_clocks[MSM_GLOBAL_TIMER];
+#else
+	return container_of(evt, struct msm_clock, clockevent);
+#endif
 }
 
 static int msm_timer_set_next_event(unsigned long cycles,
 				    struct clock_event_device *evt)
 {
-	struct msm_clock *clock = container_of(evt, struct msm_clock, clockevent);
-	uint32_t now = readl(clock->regbase + TIMER_COUNT_VAL);
+	struct msm_clock *clock = clockevent_to_clock(evt);
+	uint32_t now = readl(clock->local_counter);
 	uint32_t alarm = now + (cycles << clock->shift);
-	int late;
 
 	writel(alarm, clock->regbase + TIMER_MATCH_VAL);
-	now = readl(clock->regbase + TIMER_COUNT_VAL);
-	late = now - alarm;
-	if (late >= (-2 << clock->shift) && late < DGT_HZ*5) {
-		printk(KERN_NOTICE "msm_timer_set_next_event(%lu) clock %s, "
-		       "alarm already expired, now %x, alarm %x, late %d\n",
-		       cycles, clock->clockevent.name, now, alarm, late);
-		return -ETIME;
-	}
 	return 0;
 }
 
 static void msm_timer_set_mode(enum clock_event_mode mode,
 			      struct clock_event_device *evt)
 {
-	struct msm_clock *clock = container_of(evt, struct msm_clock, clockevent);
+	struct msm_clock *clock = clockevent_to_clock(evt);
+
 	switch (mode) {
 	case CLOCK_EVT_MODE_RESUME:
 	case CLOCK_EVT_MODE_PERIODIC:
@@ -123,7 +154,7 @@ static void msm_timer_set_mode(enum clock_event_mode mode,
 }
 
 static struct msm_clock msm_clocks[] = {
-	{
+	[MSM_CLOCK_GPT] = {
 		.clockevent = {
 			.name           = "gp_timer",
 			.features       = CLOCK_EVT_FEAT_ONESHOT,
@@ -135,7 +166,7 @@ static struct msm_clock msm_clocks[] = {
 		.clocksource = {
 			.name           = "gp_timer",
 			.rating         = 200,
-			.read           = msm_gpt_read,
+			.read           = msm_read_timer_count,
 			.mask           = CLOCKSOURCE_MASK(32),
 			.flags          = CLOCK_SOURCE_IS_CONTINUOUS,
 		},
@@ -147,9 +178,12 @@ static struct msm_clock msm_clocks[] = {
 			.irq     = INT_GP_TIMER_EXP
 		},
 		.regbase = MSM_GPT_BASE,
-		.freq = GPT_HZ
+		.freq = GPT_HZ,
+		.local_counter = MSM_GPT_BASE + TIMER_COUNT_VAL,
+		.global_counter = MSM_GPT_BASE + TIMER_COUNT_VAL +
+			MSM_TMR_GLOBAL,
 	},
-	{
+	[MSM_CLOCK_DGT] = {
 		.clockevent = {
 			.name           = "dg_timer",
 			.features       = CLOCK_EVT_FEAT_ONESHOT,
@@ -161,7 +195,7 @@ static struct msm_clock msm_clocks[] = {
 		.clocksource = {
 			.name           = "dg_timer",
 			.rating         = 300,
-			.read           = msm_dgt_read,
+			.read           = msm_read_timer_count,
 			.mask           = CLOCKSOURCE_MASK((32 - MSM_DGT_SHIFT)),
 			.flags          = CLOCK_SOURCE_IS_CONTINUOUS,
 		},
@@ -174,7 +208,10 @@ static struct msm_clock msm_clocks[] = {
 		},
 		.regbase = MSM_DGT_BASE,
 		.freq = DGT_HZ >> MSM_DGT_SHIFT,
-		.shift = MSM_DGT_SHIFT
+		.shift = MSM_DGT_SHIFT,
+		.local_counter = MSM_DGT_BASE + TIMER_COUNT_VAL,
+		.global_counter = MSM_DGT_BASE + TIMER_COUNT_VAL +
+			MSM_TMR_GLOBAL,
 	}
 };
 
@@ -183,7 +220,7 @@ static void __init msm_timer_init(void)
 	int i;
 	int res;
 
-#ifdef CONFIG_ARCH_MSM8X60
+#ifdef CONFIG_ARCH_MSM_SCORPIONMP
 	writel(DGT_CLK_CTL_DIV_4, MSM_TMR_BASE + DGT_CLK_CTL);
 #endif
 
@@ -217,6 +254,48 @@ static void __init msm_timer_init(void)
 	}
 }
 
+#ifdef CONFIG_SMP
+void __cpuinit local_timer_setup(struct clock_event_device *evt)
+{
+	struct msm_clock *clock = &msm_clocks[MSM_GLOBAL_TIMER];
+
+	/* Use existing clock_event for cpu 0 */
+	if (!smp_processor_id())
+		return;
+
+	writel(DGT_CLK_CTL_DIV_4, MSM_TMR_BASE + DGT_CLK_CTL);
+
+	if (!local_clock_event) {
+		writel(0, clock->regbase  + TIMER_ENABLE);
+		writel(0, clock->regbase + TIMER_CLEAR);
+		writel(~0, clock->regbase + TIMER_MATCH_VAL);
+	}
+	evt->irq = clock->irq.irq;
+	evt->name = "local_timer";
+	evt->features = CLOCK_EVT_FEAT_ONESHOT;
+	evt->rating = clock->clockevent.rating;
+	evt->set_mode = msm_timer_set_mode;
+	evt->set_next_event = msm_timer_set_next_event;
+	evt->shift = clock->clockevent.shift;
+	evt->mult = div_sc(clock->freq, NSEC_PER_SEC, evt->shift);
+	evt->max_delta_ns =
+		clockevent_delta2ns(0xf0000000 >> clock->shift, evt);
+	evt->min_delta_ns = clockevent_delta2ns(4, evt);
+
+	local_clock_event = evt;
+
+	gic_enable_ppi(clock->irq.irq);
+
+	clockevents_register_device(evt);
+}
+
+inline int local_timer_ack(void)
+{
+	return 1;
+}
+
+#endif
+
 struct sys_timer msm_timer = {
 	.init = msm_timer_init
 };