diff options
Diffstat (limited to 'arch/arm/kernel/smp_twd.c')
-rw-r--r-- | arch/arm/kernel/smp_twd.c | 114 |
1 files changed, 108 insertions, 6 deletions
diff --git a/arch/arm/kernel/smp_twd.c b/arch/arm/kernel/smp_twd.c index 01c186222f3..36c68def2a4 100644 --- a/arch/arm/kernel/smp_twd.c +++ b/arch/arm/kernel/smp_twd.c @@ -10,13 +10,17 @@ */ #include <linux/init.h> #include <linux/kernel.h> +#include <linux/clk.h> +#include <linux/cpufreq.h> #include <linux/delay.h> #include <linux/device.h> +#include <linux/err.h> #include <linux/smp.h> #include <linux/jiffies.h> #include <linux/clockchips.h> #include <linux/irq.h> #include <linux/io.h> +#include <linux/percpu.h> #include <asm/smp_twd.h> #include <asm/hardware/gic.h> @@ -24,7 +28,12 @@ /* set up by the platform code */ void __iomem *twd_base; +static struct clk *twd_clk; static unsigned long twd_timer_rate; +static DEFINE_PER_CPU(struct clock_event_device *, twd_ce); + +static DEFINE_PER_CPU(u32, twd_ctrl); +static DEFINE_PER_CPU(u32, twd_load); static void twd_set_mode(enum clock_event_mode mode, struct clock_event_device *clk) @@ -80,6 +89,52 @@ int twd_timer_ack(void) return 0; } +#ifdef CONFIG_CPU_FREQ + +/* + * Updates clockevent frequency when the cpu frequency changes. + * Called on the cpu that is changing frequency with interrupts disabled. + */ +static void twd_update_frequency(void *data) +{ + twd_timer_rate = clk_get_rate(twd_clk); + + clockevents_update_freq(__get_cpu_var(twd_ce), twd_timer_rate); +} + +static int twd_cpufreq_transition(struct notifier_block *nb, + unsigned long state, void *data) +{ + struct cpufreq_freqs *freqs = data; + + /* + * The twd clock events must be reprogrammed to account for the new + * frequency. The timer is local to a cpu, so cross-call to the + * changing cpu. + */ + if (state == CPUFREQ_POSTCHANGE || state == CPUFREQ_RESUMECHANGE) + smp_call_function_single(freqs->cpu, twd_update_frequency, + NULL, 1); + + return NOTIFY_OK; +} + +static struct notifier_block twd_cpufreq_nb = { + .notifier_call = twd_cpufreq_transition, +}; + +static int twd_cpufreq_init(void) +{ + if (!IS_ERR_OR_NULL(twd_clk)) + return cpufreq_register_notifier(&twd_cpufreq_nb, + CPUFREQ_TRANSITION_NOTIFIER); + + return 0; +} +core_initcall(twd_cpufreq_init); + +#endif + static void __cpuinit twd_calibrate_rate(void) { unsigned long count; @@ -119,12 +174,39 @@ static void __cpuinit twd_calibrate_rate(void) } } +static struct clk *twd_get_clock(void) +{ + struct clk *clk; + int err; + + clk = clk_get_sys("smp_twd", NULL); + if (IS_ERR(clk)) { + pr_err("smp_twd: clock not found: %d\n", (int)PTR_ERR(clk)); + return clk; + } + + err = clk_enable(clk); + if (err) { + pr_err("smp_twd: clock failed to enable: %d\n", err); + clk_put(clk); + return ERR_PTR(err); + } + + return clk; +} + /* * Setup the local clock events for a CPU. */ void __cpuinit twd_timer_setup(struct clock_event_device *clk) { - twd_calibrate_rate(); + if (!twd_clk) + twd_clk = twd_get_clock(); + + if (!IS_ERR_OR_NULL(twd_clk)) + twd_timer_rate = clk_get_rate(twd_clk); + else + twd_calibrate_rate(); clk->name = "local_timer"; clk->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT | @@ -132,13 +214,33 @@ void __cpuinit twd_timer_setup(struct clock_event_device *clk) clk->rating = 350; clk->set_mode = twd_set_mode; clk->set_next_event = twd_set_next_event; - clk->shift = 20; - clk->mult = div_sc(twd_timer_rate, NSEC_PER_SEC, clk->shift); - clk->max_delta_ns = clockevent_delta2ns(0xffffffff, clk); - clk->min_delta_ns = clockevent_delta2ns(0xf, clk); - clockevents_register_device(clk); + __get_cpu_var(twd_ce) = clk; + + clockevents_config_and_register(clk, twd_timer_rate, + 0xf, 0xffffffff); /* Make sure our local interrupt controller has this enabled */ gic_enable_ppi(clk->irq); } + +#if defined(CONFIG_HOTPLUG) || defined(CONFIG_CPU_IDLE) +void twd_save(void) +{ + int this_cpu = smp_processor_id(); + + per_cpu(twd_ctrl, this_cpu) = __raw_readl(twd_base + TWD_TIMER_CONTROL); + per_cpu(twd_load, this_cpu) = __raw_readl(twd_base + TWD_TIMER_LOAD); + +} + +void twd_restore(void) +{ + int this_cpu = smp_processor_id(); + + __raw_writel(per_cpu(twd_ctrl, this_cpu), + twd_base + TWD_TIMER_CONTROL); + __raw_writel(per_cpu(twd_load, this_cpu), + twd_base + TWD_TIMER_LOAD); +} +#endif |