From mboxrd@z Thu Jan 1 00:00:00 1970 From: dinguyen@altera.com (dinguyen at altera.com) Date: Thu, 22 Aug 2013 11:30:26 -0500 Subject: [PATCHv4 4/4] clocksource: dw_apb_timer_of: Fix read_sched_clock In-Reply-To: <1377189026-16656-1-git-send-email-dinguyen@altera.com> References: <1377189026-16656-1-git-send-email-dinguyen@altera.com> Message-ID: <1377189026-16656-4-git-send-email-dinguyen@altera.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org From: Dinh Nguyen 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 Acked-by: Jamie Iles CC: Rob Herring CC: Arnd Bergmann Cc: Olof Johansson CC: Jamie Iles Cc: John Stultz Cc: Daniel Lezcano Cc: Thomas Gleixner Cc: Linus Walleij Cc: Pavel Machek Cc: Heiko Stuebner Cc: linux-arm-kernel at lists.infradead.org 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(-) 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); -- 1.7.9.5