1 files changed, 132 insertions, 8 deletions

diff --git a/arch/arm/kernel/smp_twd.c b/arch/arm/kernel/smp_twd.c
index 01c186222f3b..c8e938553d47 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>
@@ -19,13 +22,17 @@
 #include <linux/io.h>
 
 #include <asm/smp_twd.h>
+#include <asm/localtimer.h>
 #include <asm/hardware/gic.h>
 
 /* 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;
+
 static void twd_set_mode(enum clock_event_mode mode,
                         struct clock_event_device *clk)
 {
@@ -80,6 +87,58 @@ int twd_timer_ack(void)
         return 0;
 }
 
+void twd_timer_stop(struct clock_event_device *clk)
+{
+        twd_set_mode(CLOCK_EVT_MODE_UNUSED, 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;
@@ -119,12 +178,79 @@ static void __cpuinit twd_calibrate_rate(void)
         }
 }
 
+static irqreturn_t twd_handler(int irq, void *dev_id)
+{
+        struct clock_event_device *evt = *(struct clock_event_device **)dev_id;
+
+        if (twd_timer_ack()) {
+                evt->event_handler(evt);
+                return IRQ_HANDLED;
+        }
+
+        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.
  */
 void __cpuinit twd_timer_setup(struct clock_event_device *clk)
 {
-        twd_calibrate_rate();
+        struct clock_event_device **this_cpu_clk;
+
+        if (!twd_evt) {
+                int err;
+
+                twd_evt = alloc_percpu(struct clock_event_device *);
+                if (!twd_evt) {
+                        pr_err("twd: can't allocate memory\n");
+                        return;
+                }
+
+                err = request_percpu_irq(clk->irq, twd_handler,
+                                         "twd", twd_evt);
+                if (err) {
+                        pr_err("twd: can't register interrupt %d (%d)\n",
+                               clk->irq, err);
+                        return;
+                }
+        }
+
+        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 +258,11 @@ 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);
 
-        clockevents_register_device(clk);
+        this_cpu_clk = __this_cpu_ptr(twd_evt);
+        *this_cpu_clk = clk;
 
-        /* Make sure our local interrupt controller has this enabled */
-        gic_enable_ppi(clk->irq);
+        clockevents_config_and_register(clk, twd_timer_rate,
+                                        0xf, 0xffffffff);
+        enable_percpu_irq(clk->irq, 0);
 }