/* * DaVinci timer subsystem * * Author: Kevin Hilman, MontaVista Software, Inc. <source@mvista.com> * * 2007 (c) MontaVista Software, Inc. This file is licensed under * the terms of the GNU General Public License version 2. This program * is licensed "as is" without any warranty of any kind, whether express * or implied. */ #include <linux/kernel.h> #include <linux/init.h> #include <linux/types.h> #include <linux/interrupt.h> #include <linux/clocksource.h> #include <linux/clockchips.h> #include <linux/io.h> #include <linux/clk.h> #include <linux/err.h> #include <linux/platform_device.h> #include <mach/hardware.h> #include <asm/mach/irq.h> #include <asm/mach/time.h> #include <mach/cputype.h> #include <mach/time.h> #include "clock.h" static struct clock_event_device clockevent_davinci; static unsigned int davinci_clock_tick_rate; /* * This driver configures the 2 64-bit count-up timers as 4 independent * 32-bit count-up timers used as follows: */ enum { TID_CLOCKEVENT, TID_CLOCKSOURCE, }; /* Timer register offsets */ #define PID12 0x0 #define TIM12 0x10 #define TIM34 0x14 #define PRD12 0x18 #define PRD34 0x1c #define TCR 0x20 #define TGCR 0x24 #define WDTCR 0x28 /* Offsets of the 8 compare registers */ #define CMP12_0 0x60 #define CMP12_1 0x64 #define CMP12_2 0x68 #define CMP12_3 0x6c #define CMP12_4 0x70 #define CMP12_5 0x74 #define CMP12_6 0x78 #define CMP12_7 0x7c /* Timer register bitfields */ #define TCR_ENAMODE_DISABLE 0x0 #define TCR_ENAMODE_ONESHOT 0x1 #define TCR_ENAMODE_PERIODIC 0x2 #define TCR_ENAMODE_MASK 0x3 #define TGCR_TIMMODE_SHIFT 2 #define TGCR_TIMMODE_64BIT_GP 0x0 #define TGCR_TIMMODE_32BIT_UNCHAINED 0x1 #define TGCR_TIMMODE_64BIT_WDOG 0x2 #define TGCR_TIMMODE_32BIT_CHAINED 0x3 #define TGCR_TIM12RS_SHIFT 0 #define TGCR_TIM34RS_SHIFT 1 #define TGCR_RESET 0x0 #define TGCR_UNRESET 0x1 #define TGCR_RESET_MASK 0x3 #define WDTCR_WDEN_SHIFT 14 #define WDTCR_WDEN_DISABLE 0x0 #define WDTCR_WDEN_ENABLE 0x1 #define WDTCR_WDKEY_SHIFT 16 #define WDTCR_WDKEY_SEQ0 0xa5c6 #define WDTCR_WDKEY_SEQ1 0xda7e struct timer_s { char *name; unsigned int id; unsigned long period; unsigned long opts; unsigned long flags; void __iomem *base; unsigned long tim_off; unsigned long prd_off; unsigned long enamode_shift; struct irqaction irqaction; }; static struct timer_s timers[]; /* values for 'opts' field of struct timer_s */ #define TIMER_OPTS_DISABLED 0x01 #define TIMER_OPTS_ONESHOT 0x02 #define TIMER_OPTS_PERIODIC 0x04 #define TIMER_OPTS_STATE_MASK 0x07 #define TIMER_OPTS_USE_COMPARE 0x80000000 #define USING_COMPARE(t) ((t)->opts & TIMER_OPTS_USE_COMPARE) static char *id_to_name[] = { [T0_BOT] = "timer0_0", [T0_TOP] = "timer0_1", [T1_BOT] = "timer1_0", [T1_TOP] = "timer1_1", }; static int timer32_config(struct timer_s *t) { u32 tcr; struct davinci_soc_info *soc_info = &davinci_soc_info; if (USING_COMPARE(t)) { struct davinci_timer_instance *dtip = soc_info->timer_info->timers; int event_timer = ID_TO_TIMER(timers[TID_CLOCKEVENT].id); /* * Next interrupt should be the current time reg value plus * the new period (using 32-bit unsigned addition/wrapping * to 0 on overflow). This assumes that the clocksource * is setup to count to 2^32-1 before wrapping around to 0. */ __raw_writel(__raw_readl(t->base + t->tim_off) + t->period, t->base + dtip[event_timer].cmp_off); } else { tcr = __raw_readl(t->base + TCR); /* disable timer */ tcr &= ~(TCR_ENAMODE_MASK << t->enamode_shift); __raw_writel(tcr, t->base + TCR); /* reset counter to zero, set new period */ __raw_writel(0, t->base + t->tim_off); __raw_writel(t->period, t->base + t->prd_off); /* Set enable mode */ if (t->opts & TIMER_OPTS_ONESHOT) tcr |= TCR_ENAMODE_ONESHOT << t->enamode_shift; else if (t->opts & TIMER_OPTS_PERIODIC) tcr |= TCR_ENAMODE_PERIODIC << t->enamode_shift; __raw_writel(tcr, t->base + TCR); } return 0; } static inline u32 timer32_read(struct timer_s *t) { return __raw_readl(t->base + t->tim_off); } static irqreturn_t timer_interrupt(int irq, void *dev_id) { struct clock_event_device *evt = &clockevent_davinci; evt->event_handler(evt); return IRQ_HANDLED; } /* called when 32-bit counter wraps */ static irqreturn_t freerun_interrupt(int irq, void *dev_id) { return IRQ_HANDLED; } static struct timer_s timers[] = { [TID_CLOCKEVENT] = { .name = "clockevent", .opts = TIMER_OPTS_DISABLED, .irqaction = { .flags = IRQF_DISABLED | IRQF_TIMER, .handler = timer_interrupt, } }, [TID_CLOCKSOURCE] = { .name = "free-run counter", .period = ~0, .opts = TIMER_OPTS_PERIODIC, .irqaction = { .flags = IRQF_DISABLED | IRQF_TIMER, .handler = freerun_interrupt, } }, }; static void __init timer_init(void) { struct davinci_soc_info *soc_info = &davinci_soc_info; struct davinci_timer_instance *dtip = soc_info->timer_info->timers; void __iomem *base[2]; int i; /* Global init of each 64-bit timer as a whole */ for(i=0; i<2; i++) { u32 tgcr; base[i] = ioremap(dtip[i].base, SZ_4K); if (WARN_ON(!base[i])) continue; /* Disabled, Internal clock source */ __raw_writel(0, base[i] + TCR); /* reset both timers, no pre-scaler for timer34 */ tgcr = 0; __raw_writel(tgcr, base[i] + TGCR); /* Set both timers to unchained 32-bit */ tgcr = TGCR_TIMMODE_32BIT_UNCHAINED << TGCR_TIMMODE_SHIFT; __raw_writel(tgcr, base[i] + TGCR); /* Unreset timers */ tgcr |= (TGCR_UNRESET << TGCR_TIM12RS_SHIFT) | (TGCR_UNRESET << TGCR_TIM34RS_SHIFT); __raw_writel(tgcr, base[i] + TGCR); /* Init both counters to zero */ __raw_writel(0, base[i] + TIM12); __raw_writel(0, base[i] + TIM34); } /* Init of each timer as a 32-bit timer */ for (i=0; i< ARRAY_SIZE(timers); i++) { struct timer_s *t = &timers[i]; int timer = ID_TO_TIMER(t->id); u32 irq; t->base = base[timer]; if (!t->base) continue; if (IS_TIMER_BOT(t->id)) { t->enamode_shift = 6; t->tim_off = TIM12; t->prd_off = PRD12; irq = dtip[timer].bottom_irq; } else { t->enamode_shift = 22; t->tim_off = TIM34; t->prd_off = PRD34; irq = dtip[timer].top_irq; } /* Register interrupt */ t->irqaction.name = t->name; t->irqaction.dev_id = (void *)t; if (t->irqaction.handler != NULL) { irq = USING_COMPARE(t) ? dtip[i].cmp_irq : irq; setup_irq(irq, &t->irqaction); } } } /* * clocksource */ static cycle_t read_cycles(struct clocksource *cs) { struct timer_s *t = &timers[TID_CLOCKSOURCE]; return (cycles_t)timer32_read(t); } static struct clocksource clocksource_davinci = { .rating = 300, .read = read_cycles, .mask = CLOCKSOURCE_MASK(32), .shift = 24, .flags = CLOCK_SOURCE_IS_CONTINUOUS, }; /* * clockevent */ static int davinci_set_next_event(unsigned long cycles, struct clock_event_device *evt) { struct timer_s *t = &timers[TID_CLOCKEVENT]; t->period = cycles; timer32_config(t); return 0; } static void davinci_set_mode(enum clock_event_mode mode, struct clock_event_device *evt) { struct timer_s *t = &timers[TID_CLOCKEVENT]; switch (mode) { case CLOCK_EVT_MODE_PERIODIC: t->period = davinci_clock_tick_rate / (HZ); t->opts &= ~TIMER_OPTS_STATE_MASK; t->opts |= TIMER_OPTS_PERIODIC; timer32_config(t); break; case CLOCK_EVT_MODE_ONESHOT: t->opts &= ~TIMER_OPTS_STATE_MASK; t->opts |= TIMER_OPTS_ONESHOT; break; case CLOCK_EVT_MODE_UNUSED: case CLOCK_EVT_MODE_SHUTDOWN: t->opts &= ~TIMER_OPTS_STATE_MASK; t->opts |= TIMER_OPTS_DISABLED; break; case CLOCK_EVT_MODE_RESUME: break; } } static struct clock_event_device clockevent_davinci = { .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, .shift = 32, .set_next_event = davinci_set_next_event, .set_mode = davinci_set_mode, }; static void __init davinci_timer_init(void) { struct clk *timer_clk; struct davinci_soc_info *soc_info = &davinci_soc_info; unsigned int clockevent_id; unsigned int clocksource_id; static char err[] __initdata = KERN_ERR "%s: can't register clocksource!\n"; int i; clockevent_id = soc_info->timer_info->clockevent_id; clocksource_id = soc_info->timer_info->clocksource_id; timers[TID_CLOCKEVENT].id = clockevent_id; timers[TID_CLOCKSOURCE].id = clocksource_id; /* * If using same timer for both clock events & clocksource, * a compare register must be used to generate an event interrupt. * This is equivalent to a oneshot timer only (not periodic). */ if (clockevent_id == clocksource_id) { struct davinci_timer_instance *dtip = soc_info->timer_info->timers; int event_timer = ID_TO_TIMER(clockevent_id); /* Only bottom timers can use compare regs */ if (IS_TIMER_TOP(clockevent_id)) pr_warning("davinci_timer_init: Invalid use" " of system timers. Results unpredictable.\n"); else if ((dtip[event_timer].cmp_off == 0) || (dtip[event_timer].cmp_irq == 0)) pr_warning("davinci_timer_init: Invalid timer instance" " setup. Results unpredictable.\n"); else { timers[TID_CLOCKEVENT].opts |= TIMER_OPTS_USE_COMPARE; clockevent_davinci.features = CLOCK_EVT_FEAT_ONESHOT; } } timer_clk = clk_get(NULL, "timer0"); BUG_ON(IS_ERR(timer_clk)); clk_enable(timer_clk); /* init timer hw */ timer_init(); davinci_clock_tick_rate = clk_get_rate(timer_clk); /* setup clocksource */ clocksource_davinci.name = id_to_name[clocksource_id]; clocksource_davinci.mult = clocksource_khz2mult(davinci_clock_tick_rate/1000, clocksource_davinci.shift); if (clocksource_register(&clocksource_davinci)) printk(err, clocksource_davinci.name); /* setup clockevent */ clockevent_davinci.name = id_to_name[timers[TID_CLOCKEVENT].id]; clockevent_davinci.mult = div_sc(davinci_clock_tick_rate, NSEC_PER_SEC, clockevent_davinci.shift); clockevent_davinci.max_delta_ns = clockevent_delta2ns(0xfffffffe, &clockevent_davinci); clockevent_davinci.min_delta_ns = 50000; /* 50 usec */ clockevent_davinci.cpumask = cpumask_of(0); clockevents_register_device(&clockevent_davinci); for (i=0; i< ARRAY_SIZE(timers); i++) timer32_config(&timers[i]); } struct sys_timer davinci_timer = { .init = davinci_timer_init, }; /* reset board using watchdog timer */ void davinci_watchdog_reset(struct platform_device *pdev) { u32 tgcr, wdtcr; void __iomem *base; struct clk *wd_clk; base = ioremap(pdev->resource[0].start, SZ_4K); if (WARN_ON(!base)) return; wd_clk = clk_get(&pdev->dev, NULL); if (WARN_ON(IS_ERR(wd_clk))) return; clk_enable(wd_clk); /* disable, internal clock source */ __raw_writel(0, base + TCR); /* reset timer, set mode to 64-bit watchdog, and unreset */ tgcr = 0; __raw_writel(tgcr, base + TGCR); tgcr = TGCR_TIMMODE_64BIT_WDOG << TGCR_TIMMODE_SHIFT; tgcr |= (TGCR_UNRESET << TGCR_TIM12RS_SHIFT) | (TGCR_UNRESET << TGCR_TIM34RS_SHIFT); __raw_writel(tgcr, base + TGCR); /* clear counter and period regs */ __raw_writel(0, base + TIM12); __raw_writel(0, base + TIM34); __raw_writel(0, base + PRD12); __raw_writel(0, base + PRD34); /* put watchdog in pre-active state */ wdtcr = __raw_readl(base + WDTCR); wdtcr = (WDTCR_WDKEY_SEQ0 << WDTCR_WDKEY_SHIFT) | (WDTCR_WDEN_ENABLE << WDTCR_WDEN_SHIFT); __raw_writel(wdtcr, base + WDTCR); /* put watchdog in active state */ wdtcr = (WDTCR_WDKEY_SEQ1 << WDTCR_WDKEY_SHIFT) | (WDTCR_WDEN_ENABLE << WDTCR_WDEN_SHIFT); __raw_writel(wdtcr, base + WDTCR); /* write an invalid value to the WDKEY field to trigger * a watchdog reset */ wdtcr = 0x00004000; __raw_writel(wdtcr, base + WDTCR); }