Messages in this thread Patch in this message | | | From | Ahmed Ammar <> | Subject | [PATCH 1/1] [ARM] ep93xx clockevent support | Date | Wed, 22 Jul 2009 12:09:46 +0300 |
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From: Ahmed Ammar <aammar@edge-techno.com>
Based on previous work by Thomas Gleixner. --- arch/arm/Kconfig | 3 + arch/arm/mach-ep93xx/core.c | 129 ++++++++++++++++++----- arch/arm/mach-ep93xx/include/mach/ep93xx-regs.h | 6 + arch/arm/mach-ep93xx/include/mach/timex.h | 6 + 4 files changed, 118 insertions(+), 26 deletions(-)
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 74713a5..90ffb1d 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -273,6 +273,8 @@ config ARCH_EP93XX select HAVE_CLK select COMMON_CLKDEV select ARCH_REQUIRE_GPIOLIB + select GENERIC_TIME + select GENERIC_CLOCKEVENTS help This enables support for the Cirrus EP93xx series of CPUs. @@ -849,6 +851,7 @@ config HZ default AT91_TIMER_HZ if ARCH_AT91 default 100 + config AEABI bool "Use the ARM EABI to compile the kernel" help diff --git a/arch/arm/mach-ep93xx/core.c b/arch/arm/mach-ep93xx/core.c index 7983a3b..3357df4 100644 --- a/arch/arm/mach-ep93xx/core.c +++ b/arch/arm/mach-ep93xx/core.c @@ -33,6 +33,9 @@ #include <linux/termios.h> #include <linux/amba/bus.h> #include <linux/amba/serial.h> +#include <linux/clocksource.h> +#include <linux/clockchips.h> + #include <linux/io.h> #include <linux/i2c.h> #include <linux/i2c-gpio.h> @@ -100,55 +103,129 @@ void __init ep93xx_map_io(void) * to use this timer for something else. We also use timer 4 for keeping * track of lost jiffies. */ -static unsigned int last_jiffy_time; - -#define TIMER4_TICKS_PER_JIFFY ((CLOCK_TICK_RATE + (HZ/2)) / HZ) +static struct clock_event_device clockevent_ep93xx; static irqreturn_t ep93xx_timer_interrupt(int irq, void *dev_id) { - __raw_writel(1, EP93XX_TIMER1_CLEAR); - while ((signed long) - (__raw_readl(EP93XX_TIMER4_VALUE_LOW) - last_jiffy_time) - >= TIMER4_TICKS_PER_JIFFY) { - last_jiffy_time += TIMER4_TICKS_PER_JIFFY; - timer_tick(); - } - + __raw_writel(EP93XX_TC_CLEAR, EP93XX_TIMER1_CLEAR); + clockevent_ep93xx.event_handler(&clockevent_ep93xx); return IRQ_HANDLED; } + +static int ep93xx_set_next_event(unsigned long evt, + struct clock_event_device *unused) +{ + u32 tmode = __raw_readl(EP93XX_TIMER1_CONTROL); + + /* stop timer */ + __raw_writel(tmode & ~EP93XX_TC123_ENABLE, EP93XX_TIMER1_CONTROL); + /* program timer */ + __raw_writel(evt, EP93XX_TIMER1_LOAD); + /* start timer */ + __raw_writel(tmode | EP93XX_TC123_ENABLE, EP93XX_TIMER1_CONTROL); + + return 0; +} + +static void ep93xx_set_mode(enum clock_event_mode mode, + struct clock_event_device *evt) +{ + u32 tmode = EP93XX_TC123_SEL_508KHZ; + /* Disable timer */ + __raw_writel(tmode, EP93XX_TIMER1_CONTROL); + + switch(mode) { + case CLOCK_EVT_MODE_PERIODIC: + /* Set timer period */ + __raw_writel((508469 / HZ) - 1, EP93XX_TIMER1_LOAD); + tmode |= EP93XX_TC123_PERIODIC; + + case CLOCK_EVT_MODE_ONESHOT: + tmode |= EP93XX_TC123_ENABLE; + __raw_writel(tmode, EP93XX_TIMER1_CONTROL); + break; + + case CLOCK_EVT_MODE_SHUTDOWN: + case CLOCK_EVT_MODE_UNUSED: + case CLOCK_EVT_MODE_RESUME: + return; + } +} + +static struct clock_event_device clockevent_ep93xx = { + .name = "ep93xx-timer1", + .features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC, + .shift = 32, + .set_mode = ep93xx_set_mode, + .set_next_event = ep93xx_set_next_event, +}; + static struct irqaction ep93xx_timer_irq = { .name = "ep93xx timer", .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL, .handler = ep93xx_timer_interrupt, }; -static void __init ep93xx_timer_init(void) +static void __init ep93xx_clockevent_init(void) { - /* Enable periodic HZ timer. */ - __raw_writel(0x48, EP93XX_TIMER1_CONTROL); - __raw_writel((508469 / HZ) - 1, EP93XX_TIMER1_LOAD); - __raw_writel(0xc8, EP93XX_TIMER1_CONTROL); + setup_irq(IRQ_EP93XX_TIMER1, &ep93xx_timer_irq); + clockevent_ep93xx.mult = div_sc(508469, NSEC_PER_SEC, + clockevent_ep93xx.shift); + clockevent_ep93xx.max_delta_ns = + clockevent_delta2ns(0xfffffffe, &clockevent_ep93xx); + clockevent_ep93xx.min_delta_ns = + clockevent_delta2ns(0xf, &clockevent_ep93xx); + clockevent_ep93xx.cpumask = cpumask_of(0); + clockevents_register_device(&clockevent_ep93xx); +} - /* Enable lost jiffy timer. */ - __raw_writel(0x100, EP93XX_TIMER4_VALUE_HIGH); +/* + * timer4 is a 40 Bit timer, separated in a 32bit and a 8 bit + * register, EP93XX_TIMER4_VALUE_LOW stores 32 bit word. The + * controlregister is in EP93XX_TIMER4_VALUE_HIGH + */ - setup_irq(IRQ_EP93XX_TIMER1, &ep93xx_timer_irq); +cycle_t ep93xx_get_cycles(void) +{ + return __raw_readl(EP93XX_TIMER4_VALUE_LOW); } -static unsigned long ep93xx_gettimeoffset(void) +static struct clocksource clocksource_ep93xx = { + .name = "ep93xx_timer4", + .rating = 200, + .read = ep93xx_get_cycles, + .mask = 0xFFFFFFFF, + .shift = 20, + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; + +/* + * Returns current time from boot in nsecs. It's OK for this to wrap + * around for now, as it's just a relative time stamp. + */ +unsigned long long sched_clock(void) { - int offset; + return cyc2ns(&clocksource_ep93xx, ep93xx_get_cycles()); +} - offset = __raw_readl(EP93XX_TIMER4_VALUE_LOW) - last_jiffy_time; +static void __init ep93xx_clocksource_init(void) +{ + /* Reset time-stamp counter */ + __raw_writel(0x100, EP93XX_TIMER4_VALUE_HIGH); + clocksource_ep93xx.mult = + clocksource_hz2mult(983040, clocksource_ep93xx.shift); + clocksource_register(&clocksource_ep93xx); +} - /* Calculate (1000000 / 983040) * offset. */ - return offset + (53 * offset / 3072); +static void __init ep93xx_timer_init(void) +{ + ep93xx_clocksource_init(); + ep93xx_clockevent_init(); } struct sys_timer ep93xx_timer = { - .init = ep93xx_timer_init, - .offset = ep93xx_gettimeoffset, + .init = ep93xx_timer_init, }; diff --git a/arch/arm/mach-ep93xx/include/mach/ep93xx-regs.h b/arch/arm/mach-ep93xx/include/mach/ep93xx-regs.h index 36c23fb..473cdec 100644 --- a/arch/arm/mach-ep93xx/include/mach/ep93xx-regs.h +++ b/arch/arm/mach-ep93xx/include/mach/ep93xx-regs.h @@ -101,6 +101,12 @@ #define EP93XX_TIMER3_CONTROL EP93XX_TIMER_REG(0x88) #define EP93XX_TIMER3_CLEAR EP93XX_TIMER_REG(0x8c) +#define EP93XX_TC_CLEAR 0x00000001 +#define EP93XX_TC123_ENABLE 0x00000080 +#define EP93XX_TC123_PERIODIC 0x00000040 +#define EP93XX_TC123_SEL_508KHZ 0x00000008 +#define EP93XX_TC4_ENABLE 0x00000100 + #define EP93XX_I2S_BASE (EP93XX_APB_VIRT_BASE + 0x00020000) #define EP93XX_SECURITY_BASE (EP93XX_APB_VIRT_BASE + 0x00030000) diff --git a/arch/arm/mach-ep93xx/include/mach/timex.h b/arch/arm/mach-ep93xx/include/mach/timex.h index 6b3503b..ddf3a8a 100644 --- a/arch/arm/mach-ep93xx/include/mach/timex.h +++ b/arch/arm/mach-ep93xx/include/mach/timex.h @@ -1,5 +1,11 @@ /* * arch/arm/mach-ep93xx/include/mach/timex.h */ +#include <mach/ep93xx-regs.h> +#include <asm/io.h> #define CLOCK_TICK_RATE 983040 + +#define mach_read_cycles() __raw_readl(EP93XX_TIMER4_VALUE_LOW) +#define mach_cycles_to_usecs(d) (((d) * ((1000000LL << 32) / CLOCK_TICK_RATE)) >> 32) +#define mach_usecs_to_cycles(d) (((d) * (((long long)CLOCK_TICK_RATE << 32) / 1000000)) >> 32) -- 1.6.3.3
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