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Message-ID: <4D018B78.4010901@codeaurora.org>
Date: Thu, 09 Dec 2010 18:07:52 -0800
From: Jeff Ohlstein <johlstei@...eaurora.org>
To: Daniel Walker <dwalker@...eaurora.org>,
Russell King <linux@....linux.org.uk>,
Thomas Gleixner <tglx@...utronix.de>
CC: linux-arm-msm@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
Brian Swetland <swetland@...gle.com>,
Dima Zavin <dima@...roid.com>,
? <arve@...roid.com>,
David Brown <davidb@...eaurora.org>,
Bryan Huntsman <bryanh@...eaurora.org>,
Stepan Moskovchenko <stepanm@...eaurora.org>,
Gregory Bean <gbean@...eaurora.org>,
Steve Muckle <smuckle@...eaurora.org>
Subject: Re: [PATCH v2 4/6] msm: timer: SMP timer support for msm
Jeff Ohlstein wrote:
> Signed-off-by: Jeff Ohlstein <johlstei@...eaurora.org>
> ---
> arch/arm/mach-msm/include/mach/msm_iomap-8x60.h | 6 +-
> arch/arm/mach-msm/io.c | 1 +
> arch/arm/mach-msm/timer.c | 130 +++++++++++++++++++----
> 3 files changed, 115 insertions(+), 22 deletions(-)
>
> diff --git a/arch/arm/mach-msm/include/mach/msm_iomap-8x60.h b/arch/arm/mach-msm/include/mach/msm_iomap-8x60.h
> index 45bab50..873e0b7 100644
> --- a/arch/arm/mach-msm/include/mach/msm_iomap-8x60.h
> +++ b/arch/arm/mach-msm/include/mach/msm_iomap-8x60.h
> @@ -60,7 +60,11 @@
>
> #define MSM_TMR_BASE IOMEM(0xF0200000)
> #define MSM_TMR_PHYS 0x02000000
> -#define MSM_TMR_SIZE (SZ_1M)
> +#define MSM_TMR_SIZE SZ_4K
> +
> +#define MSM_TMR0_BASE IOMEM(0xF0201000)
> +#define MSM_TMR0_PHYS 0x02040000
> +#define MSM_TMR0_SIZE SZ_4K
>
> #define MSM_GPT_BASE (MSM_TMR_BASE + 0x4)
> #define MSM_DGT_BASE (MSM_TMR_BASE + 0x24)
> diff --git a/arch/arm/mach-msm/io.c b/arch/arm/mach-msm/io.c
> index d36b610..b826b6b 100644
> --- a/arch/arm/mach-msm/io.c
> +++ b/arch/arm/mach-msm/io.c
> @@ -105,6 +105,7 @@ static struct map_desc msm8x60_io_desc[] __initdata = {
> MSM_DEVICE(QGIC_DIST),
> MSM_DEVICE(QGIC_CPU),
> MSM_DEVICE(TMR),
> + MSM_DEVICE(TMR0),
> MSM_DEVICE(ACC),
> MSM_DEVICE(GCC),
> };
> diff --git a/arch/arm/mach-msm/timer.c b/arch/arm/mach-msm/timer.c
> index 950100f..92ac220 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 *global_counter;
> + void *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) >> clk->shift;
> }
>
> -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:
> @@ -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),
> .shift = 17,
> .flags = CLOCK_SOURCE_IS_CONTINUOUS,
> @@ -148,7 +179,10 @@ 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,
> },
> {
> .clockevent = {
> @@ -162,7 +196,7 @@ 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)),
> .shift = 24 - MSM_DGT_SHIFT,
> .flags = CLOCK_SOURCE_IS_CONTINUOUS,
> @@ -176,7 +210,10 @@ 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,
> }
> };
>
> @@ -185,7 +222,7 @@ 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
>
> @@ -220,6 +257,57 @@ static void __init msm_timer_init(void)
> }
> }
>
> +#ifdef CONFIG_SMP
> +void local_timer_setup(struct clock_event_device *evt)
> +{
> + unsigned long flags;
> + struct msm_clock *clock = &msm_clocks[MSM_GLOBAL_TIMER];
> +
> + 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);
> + evt->cpumask = cpumask_of(smp_processor_id());
> +
> + local_clock_event = evt;
> +
> + local_irq_save(flags);
> + get_irq_chip(clock->irq.irq)->unmask(clock->irq.irq);
> + local_irq_restore(flags);
> +
> + clockevents_register_device(evt);
> +}
> +
> +inline int local_timer_ack(void)
> +{
> + return 1;
> +}
> +
> +#ifdef CONFIG_HOTPLUG_CPU
> +void __cpuexit local_timer_stop(void)
> +{
> + struct msm_clock *clock = clockevent_to_clock(local_clock_event);
> + writel(0, clock->regbase + TIMER_MATCH_VAL);
> + writel(0, clock->regbase + TIMER_ENABLE);
> + get_irq_chip(local_clock_event->irq)->mask(local_clock_event->irq);
> +}
> +#endif
> +#endif
> +
> struct sys_timer msm_timer = {
> .init = msm_timer_init
> };
>
Thomas, do you have any additional thoughts on this? Did I answer your
questions
sufficiently in the other thread?
--
Sent by an employee of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
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