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authorHeiko Stuebner <heiko@sntech.de>2013-06-04 13:37:02 +0400
committerHeiko Stuebner <heiko@sntech.de>2013-06-12 15:47:13 +0400
commita1198f83407ae3421f3f58355a0f296d5ea6249c (patch)
tree6760cab93aa90b7456917923315632b81c7e0b5d /drivers/clocksource
parente4aa937ec75df0eea0bee03bffa3303ad36c986b (diff)
downloadlinux-a1198f83407ae3421f3f58355a0f296d5ea6249c.tar.xz
clocksource: dw_apb_timer_of: enable the use the clocksource as sched clock
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 this sptimer but can use the clocksource as sched_clock instead. Therefore enable the driver to distiguish between devices with and without sptimer based on the devicetree data and select the correct timer as sched_clock. Signed-off-by: Heiko Stuebner <heiko@sntech.de> Acked-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Jamie Iles <jamie@jamieiles.com>
Diffstat (limited to 'drivers/clocksource')
-rw-r--r--drivers/clocksource/dw_apb_timer_of.c26
1 files changed, 17 insertions, 9 deletions
diff --git a/drivers/clocksource/dw_apb_timer_of.c b/drivers/clocksource/dw_apb_timer_of.c
index ab09ed3742ee..d6c0fda76a7e 100644
--- a/drivers/clocksource/dw_apb_timer_of.c
+++ b/drivers/clocksource/dw_apb_timer_of.c
@@ -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);
-}
-static void __iomem *sched_io_base;
+ /*
+ * 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;
- u32 rate;
sched_timer = of_find_matching_node(NULL, sptimer_ids);
- if (!sched_timer)
- panic("No RTC for sched clock to use");
-
- timer_get_base_and_rate(sched_timer, &sched_io_base, &rate);
- of_node_put(sched_timer);
+ 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, rate);
+ setup_sched_clock(read_sched_clock, 32, sched_rate);
}
static const struct of_device_id osctimer_ids[] __initconst = {