diff options
Diffstat (limited to 'arch/arm/plat-nomadik/timer.c')
| -rw-r--r-- | arch/arm/plat-nomadik/timer.c | 138 |
1 files changed, 107 insertions, 31 deletions
diff --git a/arch/arm/plat-nomadik/timer.c b/arch/arm/plat-nomadik/timer.c index ef74e15..30b6433 100644 --- a/arch/arm/plat-nomadik/timer.c +++ b/arch/arm/plat-nomadik/timer.c @@ -21,10 +21,59 @@ #include <asm/mach/time.h> #include <asm/sched_clock.h> -#include <plat/mtu.h> +/* + * Guaranteed runtime conversion range in seconds for + * the clocksource and clockevent. + */ +#define MTU_MIN_RANGE 4 + +/* + * The MTU device hosts four different counters, with 4 set of + * registers. These are register names. + */ + +#define MTU_IMSC 0x00 /* Interrupt mask set/clear */ +#define MTU_RIS 0x04 /* Raw interrupt status */ +#define MTU_MIS 0x08 /* Masked interrupt status */ +#define MTU_ICR 0x0C /* Interrupt clear register */ + +/* per-timer registers take 0..3 as argument */ +#define MTU_LR(x) (0x10 + 0x10 * (x) + 0x00) /* Load value */ +#define MTU_VAL(x) (0x10 + 0x10 * (x) + 0x04) /* Current value */ +#define MTU_CR(x) (0x10 + 0x10 * (x) + 0x08) /* Control reg */ +#define MTU_BGLR(x) (0x10 + 0x10 * (x) + 0x0c) /* At next overflow */ + +/* bits for the control register */ +#define MTU_CRn_ENA 0x80 +#define MTU_CRn_PERIODIC 0x40 /* if 0 = free-running */ +#define MTU_CRn_PRESCALE_MASK 0x0c +#define MTU_CRn_PRESCALE_1 0x00 +#define MTU_CRn_PRESCALE_16 0x04 +#define MTU_CRn_PRESCALE_256 0x08 +#define MTU_CRn_32BITS 0x02 +#define MTU_CRn_ONESHOT 0x01 /* if 0 = wraps reloading from BGLR*/ + +/* Other registers are usual amba/primecell registers, currently not used */ +#define MTU_ITCR 0xff0 +#define MTU_ITOP 0xff4 + +#define MTU_PERIPH_ID0 0xfe0 +#define MTU_PERIPH_ID1 0xfe4 +#define MTU_PERIPH_ID2 0xfe8 +#define MTU_PERIPH_ID3 0xfeC + +#define MTU_PCELL0 0xff0 +#define MTU_PCELL1 0xff4 +#define MTU_PCELL2 0xff8 +#define MTU_PCELL3 0xffC + +static bool clkevt_periodic; +static u32 clk_prescale; +static u32 nmdk_cycle; /* write-once */ void __iomem *mtu_base; /* Assigned by machine code */ +#ifdef CONFIG_NOMADIK_MTU_SCHED_CLOCK /* * Override the global weak sched_clock symbol with this * local implementation which uses the clocksource to get some @@ -48,32 +97,56 @@ static void notrace nomadik_update_sched_clock(void) u32 cyc = -readl(mtu_base + MTU_VAL(0)); update_sched_clock(&cd, cyc, (u32)~0); } +#endif /* Clockevent device: use one-shot mode */ +static int nmdk_clkevt_next(unsigned long evt, struct clock_event_device *ev) +{ + writel(1 << 1, mtu_base + MTU_IMSC); + writel(evt, mtu_base + MTU_LR(1)); + /* Load highest value, enable device, enable interrupts */ + writel(MTU_CRn_ONESHOT | clk_prescale | + MTU_CRn_32BITS | MTU_CRn_ENA, + mtu_base + MTU_CR(1)); + + return 0; +} + +void nmdk_clkevt_reset(void) +{ + if (clkevt_periodic) { + + /* Timer: configure load and background-load, and fire it up */ + writel(nmdk_cycle, mtu_base + MTU_LR(1)); + writel(nmdk_cycle, mtu_base + MTU_BGLR(1)); + + writel(MTU_CRn_PERIODIC | clk_prescale | + MTU_CRn_32BITS | MTU_CRn_ENA, + mtu_base + MTU_CR(1)); + writel(1 << 1, mtu_base + MTU_IMSC); + } else { + /* Generate an interrupt to start the clockevent again */ + (void) nmdk_clkevt_next(nmdk_cycle, NULL); + } +} + static void nmdk_clkevt_mode(enum clock_event_mode mode, struct clock_event_device *dev) { - u32 cr; switch (mode) { case CLOCK_EVT_MODE_PERIODIC: - pr_err("%s: periodic mode not supported\n", __func__); + clkevt_periodic = true; + nmdk_clkevt_reset(); break; case CLOCK_EVT_MODE_ONESHOT: - /* 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(1 << 1, mtu_base + MTU_IMSC); + clkevt_periodic = false; break; case CLOCK_EVT_MODE_SHUTDOWN: case CLOCK_EVT_MODE_UNUSED: - /* disable irq */ writel(0, mtu_base + MTU_IMSC); /* disable timer */ - cr = readl(mtu_base + MTU_CR(1)); - cr &= ~MTU_CRn_ENA; - writel(cr, mtu_base + MTU_CR(1)); + writel(0, mtu_base + MTU_CR(1)); /* load some high default value */ writel(0xffffffff, mtu_base + MTU_LR(1)); break; @@ -82,16 +155,9 @@ static void nmdk_clkevt_mode(enum clock_event_mode mode, } } -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_1", - .features = CLOCK_EVT_FEAT_ONESHOT, + .features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC, .rating = 200, .set_mode = nmdk_clkevt_mode, .set_next_event = nmdk_clkevt_next, @@ -116,11 +182,23 @@ static struct irqaction nmdk_timer_irq = { .dev_id = &nmdk_clkevt, }; +void nmdk_clksrc_reset(void) +{ + /* Disable */ + writel(0, mtu_base + MTU_CR(0)); + + /* ClockSource: 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)); + + writel(clk_prescale | MTU_CRn_32BITS | MTU_CRn_ENA, + mtu_base + MTU_CR(0)); +} + void __init nmdk_timer_init(void) { unsigned long rate; struct clk *clk0; - u32 cr = MTU_CRn_32BITS; clk0 = clk_get_sys("mtu0", NULL); BUG_ON(IS_ERR(clk0)); @@ -138,30 +216,28 @@ void __init nmdk_timer_init(void) rate = clk_get_rate(clk0); if (rate > 32000000) { rate /= 16; - cr |= MTU_CRn_PRESCALE_16; + clk_prescale = MTU_CRn_PRESCALE_16; } else { - cr |= MTU_CRn_PRESCALE_1; + clk_prescale = MTU_CRn_PRESCALE_1; } + nmdk_cycle = (rate + HZ/2) / HZ; + + /* 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_reset(); if (clocksource_mmio_init(mtu_base + MTU_VAL(0), "mtu_0", rate, 200, 32, clocksource_mmio_readl_down)) pr_err("timer: failed to initialize clock source %s\n", "mtu_0"); - +#ifdef CONFIG_NOMADIK_MTU_SCHED_CLOCK init_sched_clock(&cd, nomadik_update_sched_clock, 32, rate); - +#endif /* Timer 1 is used for events */ clockevents_calc_mult_shift(&nmdk_clkevt, rate, MTU_MIN_RANGE); - writel(cr | MTU_CRn_ONESHOT, mtu_base + MTU_CR(1)); /* off, currently */ - nmdk_clkevt.max_delta_ns = clockevent_delta2ns(0xffffffff, &nmdk_clkevt); nmdk_clkevt.min_delta_ns = |