From a602f0f2f04f150fa1f7312b9e601e8e1a5afe10 Mon Sep 17 00:00:00 2001 From: Uwe Kleine-König Date: Thu, 17 Dec 2009 12:43:29 +0100 Subject: arm/{pxa,sa1100,nomadik}: Don't disable irqs in set_next_event and set_mode MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit These functions are called with irqs already off. This commit removes the calls to raw_local_irq_save and raw_local_irq_restore on platforms that don't have to use a shared interrupt for their timekeeping. Signed-off-by: Uwe Kleine-König --- arch/arm/plat-nomadik/timer.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-) (limited to 'arch/arm/plat-nomadik/timer.c') diff --git a/arch/arm/plat-nomadik/timer.c b/arch/arm/plat-nomadik/timer.c index 62f18ad43a2..fa7cb3a57cb 100644 --- a/arch/arm/plat-nomadik/timer.c +++ b/arch/arm/plat-nomadik/timer.c @@ -49,24 +49,17 @@ static struct clocksource nmdk_clksrc = { static void nmdk_clkevt_mode(enum clock_event_mode mode, struct clock_event_device *dev) { - unsigned long flags; - switch (mode) { case CLOCK_EVT_MODE_PERIODIC: - /* enable interrupts -- and count current value? */ - raw_local_irq_save(flags); + /* count current value? */ writel(readl(mtu_base + MTU_IMSC) | 1, mtu_base + MTU_IMSC); - raw_local_irq_restore(flags); break; case CLOCK_EVT_MODE_ONESHOT: BUG(); /* Not supported, yet */ /* FALLTHROUGH */ case CLOCK_EVT_MODE_SHUTDOWN: case CLOCK_EVT_MODE_UNUSED: - /* disable irq */ - raw_local_irq_save(flags); writel(readl(mtu_base + MTU_IMSC) & ~1, mtu_base + MTU_IMSC); - raw_local_irq_restore(flags); break; case CLOCK_EVT_MODE_RESUME: break; -- cgit v1.2.3-70-g09d2 From b102c01faed5e0083a4e6d29a2d61f6b57716e94 Mon Sep 17 00:00:00 2001 From: Alessandro Rubini Date: Fri, 5 Mar 2010 12:38:51 +0100 Subject: ARM: 5978/1: plat-nomadik: use one-shot clock events This is a complete rewrite of the MTU driver, using one-shot for events and a free-running timer for stamping. It allows CONFIG_NO_HZ and CONFIG_HIGH_RES_TIMERS to work on Nomadik and Ux500. Signed-off-by: Alessandro Rubini Acked-by: Linus Walleij Acked-by: Andrea Gallo Signed-off-by: Russell King --- arch/arm/plat-nomadik/timer.c | 125 +++++++++++++++++++++--------------------- 1 file changed, 63 insertions(+), 62 deletions(-) (limited to 'arch/arm/plat-nomadik/timer.c') diff --git a/arch/arm/plat-nomadik/timer.c b/arch/arm/plat-nomadik/timer.c index fa7cb3a57cb..db67402518a 100644 --- a/arch/arm/plat-nomadik/timer.c +++ b/arch/arm/plat-nomadik/timer.c @@ -2,7 +2,7 @@ * linux/arch/arm/mach-nomadik/timer.c * * Copyright (C) 2008 STMicroelectronics - * Copyright (C) 2009 Alessandro Rubini, somewhat based on at91sam926x + * Copyright (C) 2010 Alessandro Rubini * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2, as @@ -18,123 +18,124 @@ #include -static u32 nmdk_count; /* accumulated count */ -static u32 nmdk_cycle; /* write-once */ +void __iomem *mtu_base; /* ssigned by machine code */ -/* setup by the platform code */ -void __iomem *mtu_base; - -/* - * clocksource: the MTU device is a decrementing counters, so we negate - * the value being read. - */ +/* clocksource: MTU decrements, so we negate the value being read. */ static cycle_t nmdk_read_timer(struct clocksource *cs) { - u32 count = readl(mtu_base + MTU_VAL(0)); - return nmdk_count + nmdk_cycle - count; - + return -readl(mtu_base + MTU_VAL(0)); } static struct clocksource nmdk_clksrc = { .name = "mtu_0", - .rating = 120, + .rating = 200, .read = nmdk_read_timer, + .mask = CLOCKSOURCE_MASK(32), .shift = 20, .flags = CLOCK_SOURCE_IS_CONTINUOUS, }; -/* - * Clockevent device: currently only periodic mode is supported - */ +/* Clockevent device: use one-shot mode */ static void nmdk_clkevt_mode(enum clock_event_mode mode, struct clock_event_device *dev) { + u32 cr; + switch (mode) { case CLOCK_EVT_MODE_PERIODIC: - /* count current value? */ - writel(readl(mtu_base + MTU_IMSC) | 1, mtu_base + MTU_IMSC); + pr_err("%s: periodic mode not supported\n", __func__); break; case CLOCK_EVT_MODE_ONESHOT: - BUG(); /* Not supported, yet */ - /* FALLTHROUGH */ + /* Load highest value, enable device, enable interrupts */ + cr = readl(mtu_base + MTU_CR(1)); + writel(0, mtu_base + MTU_LR(1)); + writel(cr | MTU_CRn_ENA, mtu_base + MTU_CR(1)); + writel(0x2, mtu_base + MTU_IMSC); + break; case CLOCK_EVT_MODE_SHUTDOWN: case CLOCK_EVT_MODE_UNUSED: - writel(readl(mtu_base + MTU_IMSC) & ~1, mtu_base + MTU_IMSC); + /* disable irq */ + writel(0, mtu_base + MTU_IMSC); break; case CLOCK_EVT_MODE_RESUME: break; } } +static int nmdk_clkevt_next(unsigned long evt, struct clock_event_device *ev) +{ + /* writing the value has immediate effect */ + writel(evt, mtu_base + MTU_LR(1)); + return 0; +} + static struct clock_event_device nmdk_clkevt = { - .name = "mtu_0", - .features = CLOCK_EVT_FEAT_PERIODIC, + .name = "mtu_1", + .features = CLOCK_EVT_FEAT_ONESHOT, .shift = 32, - .rating = 100, + .rating = 200, .set_mode = nmdk_clkevt_mode, + .set_next_event = nmdk_clkevt_next, }; /* - * IRQ Handler for the timer 0 of the MTU block. The irq is not shared - * as we are the only users of mtu0 by now. + * IRQ Handler for timer 1 of the MTU block. */ static irqreturn_t nmdk_timer_interrupt(int irq, void *dev_id) { - /* ack: "interrupt clear register" */ - writel(1 << 0, mtu_base + MTU_ICR); - - /* we can't count lost ticks, unfortunately */ - nmdk_count += nmdk_cycle; - nmdk_clkevt.event_handler(&nmdk_clkevt); + struct clock_event_device *evdev = dev_id; + writel(1 << 1, mtu_base + MTU_ICR); /* Interrupt clear reg */ + evdev->event_handler(evdev); return IRQ_HANDLED; } -/* - * Set up timer interrupt, and return the current time in seconds. - */ static struct irqaction nmdk_timer_irq = { .name = "Nomadik Timer Tick", .flags = IRQF_DISABLED | IRQF_TIMER, .handler = nmdk_timer_interrupt, + .dev_id = &nmdk_clkevt, }; -static void nmdk_timer_reset(void) -{ - u32 cr; - - writel(0, mtu_base + MTU_CR(0)); /* off */ - - /* configure load and background-load, and fire it up */ - writel(nmdk_cycle, mtu_base + MTU_LR(0)); - writel(nmdk_cycle, mtu_base + MTU_BGLR(0)); - cr = MTU_CRn_PERIODIC | MTU_CRn_PRESCALE_1 | MTU_CRn_32BITS; - writel(cr, mtu_base + MTU_CR(0)); - writel(cr | MTU_CRn_ENA, mtu_base + MTU_CR(0)); -} - void __init nmdk_timer_init(void) { unsigned long rate; - int bits; - - rate = CLOCK_TICK_RATE; /* 2.4MHz */ - nmdk_cycle = (rate + HZ/2) / HZ; + u32 cr = MTU_CRn_32BITS;; + + /* + * Tick rate is 2.4MHz for Nomadik and 110MHz for ux500: + * use a divide-by-16 counter if it's more than 16MHz + */ + rate = CLOCK_TICK_RATE; + if (rate > 16 << 20) { + rate /= 16; + cr |= MTU_CRn_PRESCALE_16; + } else { + cr |= MTU_CRn_PRESCALE_1; + } - /* Init the timer and register clocksource */ - nmdk_timer_reset(); + /* Timer 0 is the free running clocksource */ + writel(cr, mtu_base + MTU_CR(0)); + writel(0, mtu_base + MTU_LR(0)); + writel(0, mtu_base + MTU_BGLR(0)); + writel(cr | MTU_CRn_ENA, mtu_base + MTU_CR(0)); nmdk_clksrc.mult = clocksource_hz2mult(rate, nmdk_clksrc.shift); - bits = 8*sizeof(nmdk_count); - nmdk_clksrc.mask = CLOCKSOURCE_MASK(bits); if (clocksource_register(&nmdk_clksrc)) - printk(KERN_ERR "timer: failed to initialize clock " - "source %s\n", nmdk_clksrc.name); + pr_err("timer: failed to initialize clock source %s\n", + nmdk_clksrc.name); + + /* Timer 1 is used for events, fix according to rate */ + writel(cr | MTU_CRn_ONESHOT, mtu_base + MTU_CR(1)); /* off, currently */ + nmdk_clkevt.mult = div_sc(rate, NSEC_PER_SEC, nmdk_clkevt.shift); + nmdk_clkevt.max_delta_ns = + clockevent_delta2ns(0xffffffff, &nmdk_clkevt); + nmdk_clkevt.min_delta_ns = + clockevent_delta2ns(0x00000002, &nmdk_clkevt); + nmdk_clkevt.cpumask = cpumask_of(0); /* Register irq and clockevents */ setup_irq(IRQ_MTU0, &nmdk_timer_irq); - nmdk_clkevt.mult = div_sc(rate, NSEC_PER_SEC, nmdk_clkevt.shift); - nmdk_clkevt.cpumask = cpumask_of(0); clockevents_register_device(&nmdk_clkevt); } -- cgit v1.2.3-70-g09d2 From 2a847513cdecd517f7efc06296c539c3a936cf98 Mon Sep 17 00:00:00 2001 From: Linus Walleij Date: Fri, 7 May 2010 10:03:02 +0100 Subject: ARM: 6107/1: plat-nomadik: use the MTU clocksrc for sched_clock This provides some serious scheduling for the Nomadik family by introducing a sched_clock() using the MTU clock source in the same manner as e.g. OMAP or U300. This type of solutions has been discussed at no end in the past, however we need this resolution for making measurements and using HRTimers. Signed-off-by: Linus Walleij Signed-off-by: Russell King --- arch/arm/plat-nomadik/timer.c | 28 +++++++++++++++++++++++++++- 1 file changed, 27 insertions(+), 1 deletion(-) (limited to 'arch/arm/plat-nomadik/timer.c') diff --git a/arch/arm/plat-nomadik/timer.c b/arch/arm/plat-nomadik/timer.c index db67402518a..0ff3798769a 100644 --- a/arch/arm/plat-nomadik/timer.c +++ b/arch/arm/plat-nomadik/timer.c @@ -20,6 +20,15 @@ void __iomem *mtu_base; /* ssigned by machine code */ +/* + * Kernel assumes that sched_clock can be called early + * but the MTU may not yet be initialized. + */ +static cycle_t nmdk_read_timer_dummy(struct clocksource *cs) +{ + return 0; +} + /* clocksource: MTU decrements, so we negate the value being read. */ static cycle_t nmdk_read_timer(struct clocksource *cs) { @@ -29,12 +38,27 @@ static cycle_t nmdk_read_timer(struct clocksource *cs) static struct clocksource nmdk_clksrc = { .name = "mtu_0", .rating = 200, - .read = nmdk_read_timer, + .read = nmdk_read_timer_dummy, .mask = CLOCKSOURCE_MASK(32), .shift = 20, .flags = CLOCK_SOURCE_IS_CONTINUOUS, }; +/* + * Override the global weak sched_clock symbol with this + * local implementation which uses the clocksource to get some + * better resolution when scheduling the kernel. We accept that + * this wraps around for now, since it is just a relative time + * stamp. (Inspired by OMAP implementation.) + */ +unsigned long long notrace sched_clock(void) +{ + return clocksource_cyc2ns(nmdk_clksrc.read( + &nmdk_clksrc), + nmdk_clksrc.mult, + nmdk_clksrc.shift); +} + /* Clockevent device: use one-shot mode */ static void nmdk_clkevt_mode(enum clock_event_mode mode, struct clock_event_device *dev) @@ -121,6 +145,8 @@ void __init nmdk_timer_init(void) writel(cr | MTU_CRn_ENA, mtu_base + MTU_CR(0)); nmdk_clksrc.mult = clocksource_hz2mult(rate, nmdk_clksrc.shift); + /* Now the scheduling clock is ready */ + nmdk_clksrc.read = nmdk_read_timer; if (clocksource_register(&nmdk_clksrc)) pr_err("timer: failed to initialize clock source %s\n", -- cgit v1.2.3-70-g09d2