[PATCHv3,4/4] clocksource: dw_apb_timer_of: Fix read_sched_clock

Commit Message

Dinh Nguyen Aug. 21, 2013, 8:53 p.m. UTC

From: Dinh Nguyen <[e-mail]>

The read_sched_clock should return the ~value because the clock is a
countdown implementation. read_sched_clock() should be the same as
__apbt_read_clocksource().

If a separate timer for the sched_clock exist, then read_sched_clock()
will return an incorrect value. The (sched_io_base + 0x4) needs to be in
the function for both cases.

Maintain backwards compatibility for "dw-apb-timer-sp" and
"dw-apb-timer-osc".

Signed-off-by: Dinh Nguyen <[e-mail]>
Acked-by: Jamie Iles <[e-mail]>
CC: Rob Herring <[e-mail]>
CC: Arnd Bergmann <[e-mail]>
Cc: Olof Johansson <[e-mail]>
CC: Jamie Iles <[e-mail]>
Cc: John Stultz <[e-mail]>
Cc: Daniel Lezcano <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Cc: Linus Walleij <[e-mail]>
Cc: Pavel Machek <[e-mail]>
Cc: Heiko Stuebner <[e-mail]>
Cc: [e-mail]

v3:
- Use APBTMR_N_CURRENT_VALUE define in read_sched_clock()

v2:
- Maintain backwards compatibility for "dw-apb-timer-sp" and
  "dw-apb-timer-osc".
---
 drivers/clocksource/dw_apb_timer_of.c |    9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

Patch

diff --git a/drivers/clocksource/dw_apb_timer_of.c b/drivers/clocksource/dw_apb_timer_of.c
index 4cbae4f..01c1238 100644
--- a/drivers/clocksource/dw_apb_timer_of.c
+++ b/drivers/clocksource/dw_apb_timer_of.c
@@ -102,18 +102,17 @@  static void add_clocksource(struct device_node *source_timer)
 	 * timer is found. sched_io_base then points to the current_value
 	 * register of the clocksource timer.
 	 */
-	sched_io_base = iobase + 0x04;
+	sched_io_base = iobase;
 	sched_rate = rate;
 }
 
 static u32 read_sched_clock(void)
 {
-	return __raw_readl(sched_io_base);
+	return ~__raw_readl(sched_io_base + APBTMR_N_CURRENT_VALUE);
 }
 
 static const struct of_device_id sptimer_ids[] __initconst = {
 	{ .compatible = "picochip,pc3x2-rtc" },
-	{ .compatible = "snps,dw-apb-timer-sp" },
 	{ /* Sentinel */ },
 };
 
@@ -153,4 +152,6 @@  static void __init dw_apb_timer_init(struct device_node *timer)
 	num_called++;
 }
 CLOCKSOURCE_OF_DECLARE(pc3x2_timer, "picochip,pc3x2-timer", dw_apb_timer_init);
-CLOCKSOURCE_OF_DECLARE(apb_timer, "snps,dw-apb-timer-osc", dw_apb_timer_init);
+CLOCKSOURCE_OF_DECLARE(apb_timer_osc, "snps,dw-apb-timer-osc", dw_apb_timer_init);
+CLOCKSOURCE_OF_DECLARE(apb_timer_sp, "snps,dw-apb-timer-sp", dw_apb_timer_init);
+CLOCKSOURCE_OF_DECLARE(apb_timer, "snps,dw-apb-timer", dw_apb_timer_init);