[PATCH 2/6] clocksource: time-armada-370-xp: add local timer support
Gregory CLEMENT
gregory.clement at free-electrons.com
Wed Jan 23 08:11:41 EST 2013
On 01/21/2013 06:53 PM, Gregory CLEMENT wrote:
> 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.
John,
Do you have any comments on this patch before I send a second patch set
to take into account the remarks I got on the other patches ?
Thanks,
>
> Signed-off-by: Gregory CLEMENT <gregory.clement at 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..757f034 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;
>
> +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
> + }
> +}
>
--
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com
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