diff options
Diffstat (limited to 'arch/arm/mach-realview/localtimer.c')
| -rw-r--r-- | arch/arm/mach-realview/localtimer.c | 94 |
1 files changed, 65 insertions, 29 deletions
diff --git a/arch/arm/mach-realview/localtimer.c b/arch/arm/mach-realview/localtimer.c index 529eb6979e6..4f87b4d09c7 100644 --- a/arch/arm/mach-realview/localtimer.c +++ b/arch/arm/mach-realview/localtimer.c @@ -16,8 +16,8 @@ #include <linux/jiffies.h> #include <linux/percpu.h> #include <linux/clockchips.h> +#include <linux/irq.h> -#include <asm/mach/time.h> #include <asm/hardware/arm_twd.h> #include <asm/hardware/gic.h> #include <asm/hardware.h> @@ -43,6 +43,43 @@ void local_timer_interrupt(void) static unsigned long mpcore_timer_rate; +static void local_timer_set_mode(enum clock_event_mode mode, + struct clock_event_device *clk) +{ + void __iomem *base = TWD_BASE(smp_processor_id()); + unsigned long ctrl; + + switch(mode) { + case CLOCK_EVT_MODE_PERIODIC: + /* timer load already set up */ + ctrl = TWD_TIMER_CONTROL_ENABLE | TWD_TIMER_CONTROL_IT_ENABLE + | TWD_TIMER_CONTROL_PERIODIC; + break; + case CLOCK_EVT_MODE_ONESHOT: + /* period set, and timer enabled in 'next_event' hook */ + ctrl = TWD_TIMER_CONTROL_IT_ENABLE | TWD_TIMER_CONTROL_ONESHOT; + break; + case CLOCK_EVT_MODE_UNUSED: + case CLOCK_EVT_MODE_SHUTDOWN: + default: + ctrl = 0; + } + + __raw_writel(ctrl, base + TWD_TIMER_CONTROL); +} + +static int local_timer_set_next_event(unsigned long evt, + struct clock_event_device *unused) +{ + void __iomem *base = TWD_BASE(smp_processor_id()); + unsigned long ctrl = __raw_readl(base + TWD_TIMER_CONTROL); + + __raw_writel(evt, base + TWD_TIMER_COUNTER); + __raw_writel(ctrl | TWD_TIMER_CONTROL_ENABLE, base + TWD_TIMER_CONTROL); + + return 0; +} + /* * local_timer_ack: checks for a local timer interrupt. * @@ -61,12 +98,11 @@ int local_timer_ack(void) return 0; } -void __cpuinit local_timer_setup(unsigned int cpu) +static void __cpuinit twd_calibrate_rate(unsigned int cpu) { void __iomem *base = TWD_BASE(cpu); - unsigned int load, offset; + unsigned long load, count; u64 waitjiffies; - unsigned int count; /* * If this is the first time round, we need to work out how fast @@ -104,36 +140,36 @@ void __cpuinit local_timer_setup(unsigned int cpu) load = mpcore_timer_rate / HZ; __raw_writel(load, base + TWD_TIMER_LOAD); - __raw_writel(0x7, base + TWD_TIMER_CONTROL); - - /* - * Now maneuver our local tick into the right part of the jiffy. - * Start by working out where within the tick our local timer - * interrupt should go. - */ - offset = ((mpcore_timer_rate / HZ) / (NR_CPUS + 1)) * (cpu + 1); +} - /* - * gettimeoffset() will return a number of us since the last tick. - * Convert this number of us to a local timer tick count. - * Be careful of integer overflow whilst keeping maximum precision. - * - * with HZ=100 and 1MHz (fpga) ~ 1GHz processor: - * load = 1 ~ 10,000 - * mpcore_timer_rate/10000 = 100 ~ 100,000 - * - * so the multiply value will be less than 10^9 always. - */ - load = (system_timer->offset() * (mpcore_timer_rate / 10000)) / 100; +/* + * Setup the local clock events for a CPU. + */ +void __cpuinit local_timer_setup(unsigned int cpu) +{ + struct clock_event_device *clk = &per_cpu(local_clockevent, cpu); + unsigned long flags; - /* Add on our offset to get the load value */ - load = (load + offset) % (mpcore_timer_rate / HZ); + twd_calibrate_rate(cpu); - __raw_writel(load, base + TWD_TIMER_COUNTER); + clk->name = "local_timer"; + clk->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT; + clk->rating = 350; + clk->set_mode = local_timer_set_mode; + clk->set_next_event = local_timer_set_next_event; + clk->irq = IRQ_LOCALTIMER; + clk->cpumask = cpumask_of_cpu(cpu); + clk->shift = 20; + clk->mult = div_sc(mpcore_timer_rate, NSEC_PER_SEC, clk->shift); + clk->max_delta_ns = clockevent_delta2ns(0xffffffff, clk); + clk->min_delta_ns = clockevent_delta2ns(0xf, clk); /* Make sure our local interrupt controller has this enabled */ - __raw_writel(1 << IRQ_LOCALTIMER, - __io_address(REALVIEW_GIC_DIST_BASE) + GIC_DIST_ENABLE_SET); + local_irq_save(flags); + get_irq_chip(IRQ_LOCALTIMER)->unmask(IRQ_LOCALTIMER); + local_irq_restore(flags); + + clockevents_register_device(clk); } /* |