[PATCH v2 2/5] clocksource: time-armada-370-xp: add local timer support

Gregory CLEMENT
2013-01-25T17:32:42Z

On the SOCs Armada 370 and Armada XP, each CPU comes with two private
timers. This patch use the timer 0 of each CPU as local timer for the
clockevent if CONFIG_LOCAL_TIMER is selected. In the other case, use
only the private Timer 0 of CPU 0.

Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
---
drivers/clocksource/time-armada-370-xp.c | 150 ++++++++++++++++++++++--------
1 file changed, 112 insertions(+), 38 deletions(-)

diff --git a/drivers/clocksource/time-armada-370-xp.c b/drivers/clocksource/time-armada-370-xp.c
index a4605fd..47a6730 100644
--- a/drivers/clocksource/time-armada-370-xp.c
+++ b/drivers/clocksource/time-armada-370-xp.c
@@ -27,8 +27,10 @@
#include <linux/of_address.h>
#include <linux/irq.h>
#include <linux/module.h>
-#include <asm/sched_clock.h>

+#include <asm/sched_clock.h>
+#include <asm/localtimer.h>
+#include <linux/percpu.h>
/*
* Timer block registers.
*/
@@ -49,6 +51,7 @@
#define TIMER1_RELOAD_OFF 0x0018
#define TIMER1_VAL_OFF 0x001c

+#define LCL_TIMER_EVENTS_STATUS 0x0028
/* Global timers are connected to the coherency fabric clock, and the
below divider reduces their incrementing frequency. */
#define TIMER_DIVIDER_SHIFT 5
@@ -57,14 +60,17 @@
/*
* SoC-specific data.
*/
-static void __iomem *timer_base;
-static int timer_irq;
+static void __iomem *timer_base, *local_base;
+static unsigned int timer_clk;
+static bool timer25Mhz = true;

/*
* Number of timer ticks per jiffy.
*/
static u32 ticks_per_jiffy;

+static struct clock_event_device __percpu **percpu_armada_370_xp_evt;
+
static u32 notrace armada_370_xp_read_sched_clock(void)
{
return ~readl(timer_base + TIMER0_VAL_OFF);
@@ -78,24 +84,23 @@ armada_370_xp_clkevt_next_event(unsigned long delta,
struct clock_event_device *dev)
{
u32 u;
-
/*
* Clear clockevent timer interrupt.
*/
- writel(TIMER1_CLR_MASK, timer_base + TIMER_EVENTS_STATUS);
+ writel(TIMER0_CLR_MASK, local_base + LCL_TIMER_EVENTS_STATUS);

/*
* Setup new clockevent timer value.
*/
- writel(delta, timer_base + TIMER1_VAL_OFF);
+ writel(delta, local_base + TIMER0_VAL_OFF);

/*
* Enable the timer.
*/
- u = readl(timer_base + TIMER_CTRL_OFF);
- u = ((u & ~TIMER1_RELOAD_EN) | TIMER1_EN |
- TIMER1_DIV(TIMER_DIVIDER_SHIFT));
- writel(u, timer_base + TIMER_CTRL_OFF);
+ u = readl(local_base + TIMER_CTRL_OFF);
+ u = ((u & ~TIMER0_RELOAD_EN) | TIMER0_EN |
+ TIMER0_DIV(TIMER_DIVIDER_SHIFT));
+ writel(u, local_base + TIMER_CTRL_OFF);

return 0;
}
@@ -107,37 +112,38 @@ armada_370_xp_clkevt_mode(enum clock_event_mode mode,
u32 u;

if (mode == CLOCK_EVT_MODE_PERIODIC) {
+
/*
* Setup timer to fire at 1/HZ intervals.
*/
- writel(ticks_per_jiffy - 1, timer_base + TIMER1_RELOAD_OFF);
- writel(ticks_per_jiffy - 1, timer_base + TIMER1_VAL_OFF);
+ writel(ticks_per_jiffy - 1, local_base + TIMER0_RELOAD_OFF);
+ writel(ticks_per_jiffy - 1, local_base + TIMER0_VAL_OFF);

/*
* Enable timer.
*/
- u = readl(timer_base + TIMER_CTRL_OFF);

- writel((u | TIMER1_EN | TIMER1_RELOAD_EN |
- TIMER1_DIV(TIMER_DIVIDER_SHIFT)),
- timer_base + TIMER_CTRL_OFF);
+ u = readl(local_base + TIMER_CTRL_OFF);
+
+ writel((u | TIMER0_EN | TIMER0_RELOAD_EN |
+ TIMER0_DIV(TIMER_DIVIDER_SHIFT)),
+ local_base + TIMER_CTRL_OFF);
} else {
/*
* Disable timer.
*/
- u = readl(timer_base + TIMER_CTRL_OFF);
- writel(u & ~TIMER1_EN, timer_base + TIMER_CTRL_OFF);
+ u = readl(local_base + TIMER_CTRL_OFF);
+ writel(u & ~TIMER0_EN, local_base + TIMER_CTRL_OFF);

/*
* ACK pending timer interrupt.
*/
- writel(TIMER1_CLR_MASK, timer_base + TIMER_EVENTS_STATUS);
-
+ writel(TIMER0_CLR_MASK, local_base + LCL_TIMER_EVENTS_STATUS);
}
}

static struct clock_event_device armada_370_xp_clkevt = {
- .name = "armada_370_xp_tick",
+ .name = "armada_370_xp_per_cpu_tick",
.features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC,
.shift = 32,
.rating = 300,
@@ -150,32 +156,78 @@ static irqreturn_t armada_370_xp_timer_interrupt(int irq, void *dev_id)
/*
* ACK timer interrupt and call event handler.
*/
+ struct clock_event_device *evt = *(struct clock_event_device **)dev_id;

- writel(TIMER1_CLR_MASK, timer_base + TIMER_EVENTS_STATUS);
- armada_370_xp_clkevt.event_handler(&armada_370_xp_clkevt);
+ writel(TIMER0_CLR_MASK, local_base + LCL_TIMER_EVENTS_STATUS);
+ evt->event_handler(evt);

return IRQ_HANDLED;
}

-static struct irqaction armada_370_xp_timer_irq = {
- .name = "armada_370_xp_tick",
- .flags = IRQF_DISABLED | IRQF_TIMER,
- .handler = armada_370_xp_timer_interrupt
+/*
+ * Setup the local clock events for a CPU.
+ */
+static int __cpuinit armada_370_xp_timer_setup(struct clock_event_device *evt)
+{
+ u32 u;
+ int cpu = smp_processor_id();
+
+ /* Use existing clock_event for cpu 0 */
+ if (!smp_processor_id())
+ return 0;
+
+ u = readl(local_base + TIMER_CTRL_OFF);
+ if (timer25Mhz)
+ writel(u | TIMER0_25MHZ, local_base + TIMER_CTRL_OFF);
+ else
+ writel(u & ~TIMER0_25MHZ, local_base + TIMER_CTRL_OFF);
+
+ evt->name = armada_370_xp_clkevt.name;
+ evt->irq = armada_370_xp_clkevt.irq;
+ evt->features = armada_370_xp_clkevt.features;
+ evt->shift = armada_370_xp_clkevt.shift;
+ evt->rating = armada_370_xp_clkevt.rating,
+ evt->set_next_event = armada_370_xp_clkevt_next_event,
+ evt->set_mode = armada_370_xp_clkevt_mode,
+ evt->cpumask = cpumask_of(cpu);
+
+ *__this_cpu_ptr(percpu_armada_370_xp_evt) = evt;
+
+ clockevents_config_and_register(evt, timer_clk, 1, 0xfffffffe);
+ enable_percpu_irq(evt->irq, 0);
+
+ return 0;
+}
+
+static void armada_370_xp_timer_stop(struct clock_event_device *evt)
+{
+ evt->set_mode(CLOCK_EVT_MODE_UNUSED, evt);
+ disable_percpu_irq(evt->irq);
+}
+
+static struct local_timer_ops armada_370_xp_local_timer_ops __cpuinitdata = {
+ .setup = armada_370_xp_timer_setup,
+ .stop = armada_370_xp_timer_stop,
};

void __init armada_370_xp_timer_init(void)
{
u32 u;
struct device_node *np;
- unsigned int timer_clk;
+ int res;
+
np = of_find_compatible_node(NULL, NULL, "marvell,armada-370-xp-timer");
timer_base = of_iomap(np, 0);
WARN_ON(!timer_base);
+ local_base = of_iomap(np, 1);

if (of_find_property(np, "marvell,timer-25Mhz", NULL)) {
/* The fixed 25MHz timer is available so let's use it */
+ u = readl(local_base + TIMER_CTRL_OFF);
+ writel(u | TIMER0_25MHZ,
+ local_base + TIMER_CTRL_OFF);
u = readl(timer_base + TIMER_CTRL_OFF);
- writel(u | TIMER0_25MHZ | TIMER1_25MHZ,
+ writel(u | TIMER0_25MHZ,
timer_base + TIMER_CTRL_OFF);
timer_clk = 25000000;
} else {
@@ -183,15 +235,23 @@ void __init armada_370_xp_timer_init(void)
struct clk *clk = of_clk_get(np, 0);
WARN_ON(IS_ERR(clk));
rate = clk_get_rate(clk);
+ u = readl(local_base + TIMER_CTRL_OFF);
+ writel(u & ~(TIMER0_25MHZ),
+ local_base + TIMER_CTRL_OFF);
+
u = readl(timer_base + TIMER_CTRL_OFF);
- writel(u & ~(TIMER0_25MHZ | TIMER1_25MHZ),
+ writel(u & ~(TIMER0_25MHZ),
timer_base + TIMER_CTRL_OFF);
+
timer_clk = rate / TIMER_DIVIDER;
+ timer25Mhz = false;
}

- /* We use timer 0 as clocksource, and timer 1 for
- clockevents */
- timer_irq = irq_of_parse_and_map(np, 1);
+ /*
+ * We use timer 0 as clocksource, and private(local) timer 0
+ * for clockevents
+ */
+ armada_370_xp_clkevt.irq = irq_of_parse_and_map(np, 4);

ticks_per_jiffy = (timer_clk + HZ / 2) / HZ;

@@ -216,12 +276,26 @@ void __init armada_370_xp_timer_init(void)
"armada_370_xp_clocksource",
timer_clk, 300, 32, clocksource_mmio_readl_down);

- /*
- * Setup clockevent timer (interrupt-driven).
- */
- setup_irq(timer_irq, &armada_370_xp_timer_irq);
+ /* Register the clockevent on the private timer of CPU 0 */
armada_370_xp_clkevt.cpumask = cpumask_of(0);
clockevents_config_and_register(&armada_370_xp_clkevt,
timer_clk, 1, 0xfffffffe);
-}

+ percpu_armada_370_xp_evt = alloc_percpu(struct clock_event_device *);
+
+
+ /*
+ * Setup clockevent timer (interrupt-driven).
+ */
+ *__this_cpu_ptr(percpu_armada_370_xp_evt) = &armada_370_xp_clkevt;
+ res = request_percpu_irq(armada_370_xp_clkevt.irq,
+ armada_370_xp_timer_interrupt,
+ armada_370_xp_clkevt.name,
+ percpu_armada_370_xp_evt);
+ if (!res) {
+ enable_percpu_irq(armada_370_xp_clkevt.irq, 0);
+#ifdef CONFIG_LOCAL_TIMERS
+ local_timer_register(&armada_370_xp_local_timer_ops);
+#endif
+ }
+}
--
1.7.9.5