diff options
Diffstat (limited to 'arch/arm/plat-mxc/global_timer.c')
| -rw-r--r-- | arch/arm/plat-mxc/global_timer.c | 214 |
1 files changed, 214 insertions, 0 deletions
diff --git a/arch/arm/plat-mxc/global_timer.c b/arch/arm/plat-mxc/global_timer.c new file mode 100644 index 000000000000..607c861d2752 --- /dev/null +++ b/arch/arm/plat-mxc/global_timer.c @@ -0,0 +1,214 @@ +/* + * arch/armplat-mxc/global_timer.c + * + * based on linux/arch/arm/kernel/smp_twd.c + * + * Copyright (C) 2002 ARM Ltd. + * All Rights Reserved + * + * 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 + * published by the Free Software Foundation. + */ +#include <linux/clockchips.h> +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <linux/io.h> +#include <linux/clk.h> +#include <linux/cpufreq.h> +#include <linux/err.h> +#include <linux/seq_file.h> + +#include <asm/sched_clock.h> +#include <asm/hardware/gic.h> +#include <mach/hardware.h> + +/* global timer registers */ +#define GT_COUNT_LOWER 0x0 +#define GT_COUNT_UPPER 0x4 +#define GT_CNTRL 0x8 +#define GT_CNTRL_AOUT_INC (1 << 3) +#define GT_CNTRL_INT_EN (1 << 2) +#define GT_CNTRL_CMP_EN (1 << 1) +#define GT_CNTRL_TIMER_EN (1 << 0) +#define GT_INT_STAT 0xC +#define GT_INT_STAT_EFLG (1 << 0) +#define GT_CMP_LOWER 0x10 +#define GT_CMP_UPPER 0x14 +#define GT_AUTO_INC 0x18 + +/* set up by the platform code */ +void __iomem *timer_base; +static unsigned long timer_rate; +static struct clocksource clocksource_gtimer; +static struct clock_event_device clockevent_gtimer; + +static DEFINE_CLOCK_DATA(cd); + +static cycle_t gtimer_clock_source_read(struct clocksource *c) +{ + cycle_t upper, val; + + while (1) { + upper = __raw_readl(timer_base + GT_COUNT_UPPER); + val = __raw_readl(timer_base + GT_COUNT_LOWER); + if (upper == __raw_readl(timer_base + GT_COUNT_UPPER)) { + val |= upper << 32; + break; + } + } + + return val; +} + +unsigned long long notrace sched_clock(void) +{ + cycle_t cyc = timer_base ? gtimer_clock_source_read(&clocksource_gtimer) : 0; + return cyc_to_sched_clock(&cd, cyc, (u32)~0); +} + +static void notrace gtimer_update_sched_clock(void) +{ + cycle_t cyc = gtimer_clock_source_read(&clocksource_gtimer); + update_sched_clock(&cd, cyc, (u32)~0); +} + +static struct clocksource clocksource_gtimer = { + .name = "global_timer", + .rating = 350, + .read = gtimer_clock_source_read, + .mask = CLOCKSOURCE_MASK(64), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; + +static void gtimer_clear_int(void) +{ + if (__raw_readl(timer_base + GT_INT_STAT)) { + __raw_writel(GT_INT_STAT_EFLG, timer_base + GT_INT_STAT); + } +} + +static void gtimer_set_mode(enum clock_event_mode mode, + struct clock_event_device *clk) +{ + unsigned long ctrl; + cycle_t cmp; + + switch (mode) { + case CLOCK_EVT_MODE_PERIODIC: + cmp = gtimer_clock_source_read(&clocksource_gtimer) + (timer_rate / HZ); + __raw_writel((u32)(cmp & 0xFFFFFFFF), timer_base + GT_CMP_LOWER); + __raw_writel((u32)(cmp >> 32), timer_base + GT_CMP_UPPER); + __raw_writel(timer_rate / HZ, timer_base + GT_AUTO_INC); + /* timer load already set up */ + ctrl = GT_CNTRL_TIMER_EN | GT_CNTRL_CMP_EN | GT_CNTRL_INT_EN | + GT_CNTRL_AOUT_INC; + gtimer_clear_int(); + gic_enable_ppi(clk->irq); + break; + case CLOCK_EVT_MODE_ONESHOT: + /* period set, and timer enabled in 'next_event' hook */ + ctrl = GT_CNTRL_CMP_EN | GT_CNTRL_INT_EN; + gtimer_clear_int(); + gic_enable_ppi(clk->irq); + break; + case CLOCK_EVT_MODE_UNUSED: + case CLOCK_EVT_MODE_SHUTDOWN: + default: + ctrl = 0; + //gic_disable_ppi(clk->irq); + } + + __raw_writel(ctrl, timer_base + GT_CNTRL); +} + +static int gtimer_set_next_event(unsigned long evt, + struct clock_event_device *unused) +{ + unsigned long ctrl = __raw_readl(timer_base + GT_CNTRL); + cycle_t cmp = gtimer_clock_source_read(&clocksource_gtimer); + + ctrl |= GT_CNTRL_TIMER_EN; + cmp += (cycle_t)evt; + + __raw_writel((u32)(cmp & 0xFFFFFFFF), timer_base + GT_CMP_LOWER); + __raw_writel((u32)(cmp >> 32), timer_base + GT_CMP_UPPER); + __raw_writel(ctrl, timer_base + GT_CNTRL); + + return 0; +} + +asmlinkage void __exception_irq_entry do_global_timer(struct pt_regs *regs) +{ + struct pt_regs *old_regs = set_irq_regs(regs); + int cpu = smp_processor_id(); + struct clock_event_device *evt = &clockevent_gtimer; + u32 reg; + + reg = __raw_readl(timer_base + GT_INT_STAT); + if (reg) { + gtimer_clear_int(); + __inc_irq_stat(cpu, global_timer_irqs); + evt->event_handler(evt); + } + + set_irq_regs(old_regs); + +} + +void show_global_timer_irqs(struct seq_file *p, int prec) +{ + unsigned int cpu; + + seq_printf(p, "%*s: ", prec, "GLB"); + + for_each_present_cpu(cpu) + seq_printf(p, "%10u ", __get_irq_stat(cpu, global_timer_irqs)); + + seq_printf(p, " global timer interrupts\n"); +} + +static struct clock_event_device clockevent_gtimer = { + .name = "global_timer", + .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, + .set_mode = gtimer_set_mode, + .set_next_event = gtimer_set_next_event, + .rating = 350, +}; + +/* + * Setup the global clock events for a CPU. + */ +void __init global_timer_init(struct clk *clk, void __iomem *base, int irq) +{ + clk_enable(clk); + + timer_base = base; + + /* + * init timer + */ + /* stop timer */ + __raw_writel(0, timer_base + GT_CNTRL); + /* clear timer count */ + __raw_writel(0, timer_base + GT_COUNT_LOWER); + __raw_writel(0, timer_base + GT_COUNT_UPPER); + /* clear timer int */ + gtimer_clear_int(); + /* clear timer cmp val */ + __raw_writel(0, timer_base + GT_CMP_LOWER); + __raw_writel(0, timer_base + GT_CMP_UPPER); + /* clear auto increment val */ + __raw_writel(0, timer_base + GT_AUTO_INC); + + timer_rate = clk_get_rate(clk); + init_sched_clock(&cd, gtimer_update_sched_clock, 64, timer_rate); + clocksource_register_hz(&clocksource_gtimer, timer_rate); + clockevent_gtimer.irq = irq; + clockevent_gtimer.cpumask = cpumask_of(0); + clockevents_config_and_register(&clockevent_gtimer, timer_rate, + 0xf, 0xffffffff); + + /* Make sure our local interrupt controller has this enabled */ + gic_enable_ppi(irq); +} |