clocksource: dw_apb_timer_of: use the clocksource as sched clock if necessary
From: Heiko Stuebner <heiko@...> Date: Thu, 16 May 2013 13:52:54 +0200
Commit-Message
Currently the dw_apb_timer always expects a separate special timer to be availbable for the sched_clock. Some devices using dw_apb_timers do not have the sptimer but can use the clocksource as sched_clock. Therefore this patch adds using the clocksource timer as a fallback if no usable sched timer is found. Signed-off-by: Heiko Stuebner <heiko@...>
Patch-Comment
drivers/clocksource/dw_apb_timer_of.c | 26 +++++++++++++++++--------- 1 files changed, 17 insertions(+), 9 deletions(-)
Statistics
- 17 lines added
- 9 lines removed
Changes
-------------------- drivers/clocksource/dw_apb_timer_of.c ---------------------
index ab09ed3..d6c0fda 100644
@@ -57,6 +57,9 @@ static void add_clockevent(struct device_node *event_timer)
dw_apb_clockevent_register(ced);
}
+static void __iomem *sched_io_base;
+static u32 sched_rate;
+
static void add_clocksource(struct device_node *source_timer)
{
void __iomem *iobase;
@@ -71,9 +74,15 @@ static void add_clocksource(struct device_node *source_timer)
dw_apb_clocksource_start(cs);
dw_apb_clocksource_register(cs);
+ /*
+ * Fallback to use the clocksource as sched_clock if no separate
+ * timer is found. sched_io_base then points to the current_value
+ * register of the clocksource timer.
+ */
+ sched_io_base = iobase + 0x04;
+ sched_rate = rate;
+}
static u32 read_sched_clock(void)
{
@@ -89,16 +98,15 @@ static const struct of_device_id sptimer_ids[] __initconst = {
static void init_sched_clock(void)
{
struct device_node *sched_timer;
sched_timer = of_find_matching_node(NULL, sptimer_ids);
+ if (sched_timer) {
+ timer_get_base_and_rate(sched_timer, &sched_io_base,
+ &sched_rate);
+ of_node_put(sched_timer);
+ }
+ setup_sched_clock(read_sched_clock, 32, sched_rate);
}
static const struct of_device_id osctimer_ids[] __initconst = {