ARM: OMAP2+: Disable POSTED mode for errata i103 and i767

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

Cc: stable@vgerk.kernel.org
Reported-by: Russ Dill <russ.dill@ti.com>
Cc: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Joel Fernandes <joelf@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

diff --git a/arch/arm/plat-omap/include/plat/dmtimer.h b/arch/arm/plat-omap/include/plat/dmtimer.h
index fb92abb91628a2e06f6aebc54f03a724a79c23ee..2861b155485aefa0adeb1029d6657b4081179af6 100644 (file)
--- 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);