This commit introduces the clockevent frequency update, using
a clock notifier. It will be used to support CPUFreq on platforms
using MIPS GIC based clockevents.

Signed-off-by: Ezequiel Garcia <ezequiel.gar...@imgtec.com>
---
 drivers/clocksource/mips-gic-timer.c | 31 ++++++++++++++++++++++++++++++-
 1 file changed, 30 insertions(+), 1 deletion(-)

diff --git a/drivers/clocksource/mips-gic-timer.c 
b/drivers/clocksource/mips-gic-timer.c
index 22a4daf..a155bec 100644
--- a/drivers/clocksource/mips-gic-timer.c
+++ b/drivers/clocksource/mips-gic-timer.c
@@ -79,6 +79,13 @@ static void gic_clockevent_cpu_exit(struct 
clock_event_device *cd)
        disable_percpu_irq(gic_timer_irq);
 }
 
+static void gic_update_frequency(void *data)
+{
+       unsigned long rate = (unsigned long)data;
+
+       clockevents_update_freq(this_cpu_ptr(&gic_clockevent_device), rate);
+}
+
 static int gic_cpu_notifier(struct notifier_block *nb, unsigned long action,
                                void *data)
 {
@@ -94,10 +101,26 @@ static int gic_cpu_notifier(struct notifier_block *nb, 
unsigned long action,
        return NOTIFY_OK;
 }
 
+static int gic_clk_notifier(struct notifier_block *nb, unsigned long action,
+                           void *data)
+{
+       struct clk_notifier_data *cnd = data;
+
+       if (action == POST_RATE_CHANGE)
+               on_each_cpu(gic_update_frequency, (void *)cnd->new_rate, 1);
+
+       return NOTIFY_OK;
+}
+
+
 static struct notifier_block gic_cpu_nb = {
        .notifier_call = gic_cpu_notifier,
 };
 
+static struct notifier_block gic_clk_nb = {
+       .notifier_call = gic_clk_notifier,
+};
+
 static int gic_clockevent_init(void)
 {
        int ret;
@@ -160,6 +183,7 @@ void __init gic_clocksource_init(unsigned int frequency)
 static void __init gic_clocksource_of_init(struct device_node *node)
 {
        struct clk *clk;
+       int ret;
 
        if (WARN_ON(!gic_present || !node->parent ||
                    !of_device_is_compatible(node->parent, "mti,gic")))
@@ -186,7 +210,12 @@ static void __init gic_clocksource_of_init(struct 
device_node *node)
        }
 
        __gic_clocksource_init();
-       gic_clockevent_init();
+
+       ret = gic_clockevent_init();
+       if (!ret && !IS_ERR(clk)) {
+               if (clk_notifier_register(clk, &gic_clk_nb) < 0)
+                       pr_warn("GIC: Unable to register clock notifier\n");
+       }
 
        /* And finally start the counter */
        gic_start_count();
-- 
2.3.3

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