Enabling of Posted mode is seen to cause problems on dmtimer modules on AM33xx (much like other OMAPs). Reference discussions on forums [1] [2]. Earlier patch solving this on other OMAPs [3].
For OMAP SoCs with this errata, the fix has been to not enable Posted mode. However, on some SoCs (atleast AM33xx) which carry this errata, Posted mode is enabled on reset. So we not only need to ignore enabling of the POSTED bit when the timer is requested, but also disable Posted mode if errata is present. [1] http://e2e.ti.com/support/arm/sitara_arm/f/791/t/285744.aspx [2] http://e2e.ti.com/support/arm/sitara_arm/f/791/t/270632.aspx [3] http://www.spinics.net/lists/linux-omap/msg81770.html Reported-by: Russ Dill <[email protected]> Cc: Santosh Shilimkar <[email protected]> Signed-off-by: Joel Fernandes <[email protected]> --- arch/arm/plat-omap/include/plat/dmtimer.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/arm/plat-omap/include/plat/dmtimer.h b/arch/arm/plat-omap/include/plat/dmtimer.h index fb92abb..2861b15 100644 --- a/arch/arm/plat-omap/include/plat/dmtimer.h +++ b/arch/arm/plat-omap/include/plat/dmtimer.h @@ -336,8 +336,11 @@ static inline void __omap_dm_timer_enable_posted(struct omap_dm_timer *timer) if (timer->posted) return; - if (timer->errata & OMAP_TIMER_ERRATA_I103_I767) + if (timer->errata & OMAP_TIMER_ERRATA_I103_I767) { + timer->posted = OMAP_TIMER_NONPOSTED; + __omap_dm_timer_write(timer, OMAP_TIMER_IF_CTRL_REG, 0, 0); return; + } __omap_dm_timer_write(timer, OMAP_TIMER_IF_CTRL_REG, OMAP_TIMER_CTRL_POSTED, 0); -- 1.8.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
