Amit, Thanks for posting! On Wed, Jun 18, 2014 at 4:31 AM, Amit Daniel Kachhap <amit.daniel@xxxxxxxxxxx> wrote: > This patch register the exynos mct clocksource as the current timer > as it has constant clock rate. This will generate correct udelay for the > exynos platform and avoid using unnecessary calibrated jiffies. This change > have been tested on exynos5420 based board. > > Signed-off-by: Amit Daniel Kachhap <amit.daniel@xxxxxxxxxxx> > --- > > Patches from David Riley confirmed that udelay is broken in exynos5420. > Link to those patches are, > 1) https://patchwork.kernel.org/patch/4344911/ > 2) https://patchwork.kernel.org/patch/4344881/ > > drivers/clocksource/exynos_mct.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/drivers/clocksource/exynos_mct.c b/drivers/clocksource/exynos_mct.c > index 8d64200..57cb3dc 100644 > --- a/drivers/clocksource/exynos_mct.c > +++ b/drivers/clocksource/exynos_mct.c > @@ -198,10 +198,21 @@ static u64 notrace exynos4_read_sched_clock(void) > return exynos4_frc_read(&mct_frc); > } > > +static struct delay_timer exynos4_delay_timer; > + > +static unsigned long exynos4_read_current_timer(void) > +{ > + return exynos4_frc_read(&mct_frc); This is terribly inefficient to read all 64-bits and then cast back to a 32-bit value. Replace with: return __raw_readl(reg_base + EXYNOS4_MCT_G_CNT_L); > +} > + > static void __init exynos4_clocksource_init(void) > { > exynos4_mct_frc_start(0, 0); Please rebase atop (1d80415 clocksource: exynos_mct: Don't reset the counter during boot and resume), which is in linuxnext among other places. > > + exynos4_delay_timer.read_current_timer = &exynos4_read_current_timer; > + exynos4_delay_timer.freq = clk_rate; > + register_current_timer_delay(&exynos4_delay_timer); > + > if (clocksource_register_hz(&mct_frc, clk_rate)) > panic("%s: can't register clocksource\n", mct_frc.name); It does seem to work for me though. :) -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
 |