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Diffstat (limited to 'arch/arm/kernel/smp_twd.c')
-rw-r--r--arch/arm/kernel/smp_twd.c97
1 files changed, 90 insertions, 7 deletions
diff --git a/arch/arm/kernel/smp_twd.c b/arch/arm/kernel/smp_twd.c
index a8a6682d6b5..4285daa077b 100644
--- a/arch/arm/kernel/smp_twd.c
+++ b/arch/arm/kernel/smp_twd.c
@@ -10,8 +10,11 @@
*/
#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>
@@ -25,6 +28,7 @@
/* set up by the platform code */
void __iomem *twd_base;
+static struct clk *twd_clk;
static unsigned long twd_timer_rate;
static struct clock_event_device __percpu **twd_evt;
@@ -89,6 +93,52 @@ void twd_timer_stop(struct clock_event_device *clk)
disable_percpu_irq(clk->irq);
}
+#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(*__this_cpu_ptr(twd_evt), 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(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;
@@ -140,6 +190,35 @@ static irqreturn_t twd_handler(int irq, void *dev_id)
return IRQ_NONE;
}
+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_prepare(clk);
+ if (err) {
+ pr_err("smp_twd: clock failed to prepare: %d\n", err);
+ clk_put(clk);
+ return ERR_PTR(err);
+ }
+
+ err = clk_enable(clk);
+ if (err) {
+ pr_err("smp_twd: clock failed to enable: %d\n", err);
+ clk_unprepare(clk);
+ clk_put(clk);
+ return ERR_PTR(err);
+ }
+
+ return clk;
+}
+
/*
* Setup the local clock events for a CPU.
*/
@@ -165,7 +244,15 @@ 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();
+
+ __raw_writel(0, twd_base + TWD_TIMER_CONTROL);
clk->name = "local_timer";
clk->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT |
@@ -173,15 +260,11 @@ 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);
this_cpu_clk = __this_cpu_ptr(twd_evt);
*this_cpu_clk = clk;
- clockevents_register_device(clk);
-
+ clockevents_config_and_register(clk, twd_timer_rate,
+ 0xf, 0xffffffff);
enable_percpu_irq(clk->irq, 0);
}