diff mbox

[2/2] clocksource: dw_apb_timer_of: Fix read_sched_clock

Message ID 1371514129-22801-3-git-send-email-dinguyen@altera.com (mailing list archive)
State New, archived
Headers show

Commit Message

Dinh Nguyen June 18, 2013, 12:08 a.m. UTC 
From: Dinh Nguyen <dinguyen@altera.com>

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.

Also, remove the use of "dw-apb-timer-sp" and "dw-apb-timer-osc" since
they are the same DW clock.

Signed-off-by: Dinh Nguyen <dinguyen@altera.com>
CC: Rob Herring <rob.herring@calxeda.com>
CC: Arnd Bergmann <arnd@arndb.de>
Cc: Olof Johansson <olof@lixom.net>
CC: Jamie Iles <jamie@jamieiles.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Pavel Machek <pavel@denx.de>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: linux-arm-kernel@lists.infradead.org
---
 drivers/clocksource/dw_apb_timer_of.c |    7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

Comments

Jamie Iles June 18, 2013, 9:23 a.m. UTC | #1 
Hi Dinh,

On Mon, Jun 17, 2013 at 07:08:49PM -0500, dinguyen@altera.com wrote:
> From: Dinh Nguyen <dinguyen@altera.com>
> 
> 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.

Actually the old behaviour is correct for picoxcell as we're using the 
DesignWare RTC rather than the counter block and the RTC does count 
upwards, but your change will work as we'll start using the regular 
timers anyway.

Looks good to me though.

Acked-by: Jamie Iles <jamie@jamieiles.com>

for the series.

Jamie
diff mbox

Patch

diff --git a/drivers/clocksource/dw_apb_timer_of.c b/drivers/clocksource/dw_apb_timer_of.c
index cef5544..8dcbd4e 100644
--- a/drivers/clocksource/dw_apb_timer_of.c
+++ b/drivers/clocksource/dw_apb_timer_of.c
@@ -104,18 +104,17 @@  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 + 0x4);
 }
 
 static const struct of_device_id sptimer_ids[] __initconst = {
 	{ .compatible = "picochip,pc3x2-rtc" },
-	{ .compatible = "snps,dw-apb-timer-sp" },
 	{ /* Sentinel */ },
 };
 
@@ -155,4 +154,4 @@  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, "snps,dw-apb-timer", dw_apb_timer_init);