From 9cc268d5bbc097ae5a3ae236fb2461ea113274bf Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Tue, 19 Mar 2013 12:38:15 -0500 Subject: [PATCH] ARM: OMAP: Simplify dmtimer context-loss handling The context loss handling in dmtimer appears to assume that omap_dm_timer_set_load_start() or omap_dm_timer_start() and omap_dm_timer_stop() bracket all interactions. Only the first two restore the context and the last updates the context loss counter. However omap_dm_timer_set_load() or omap_dm_timer_set_match() can reasonably be called outside this bracketing, and the fact that they call omap_dm_timer_enable() / omap_dm_timer_disable() suggest that is expected. So if, after a transition into and out of off-mode which would cause the dm timer to loose all state, omap_dm_timer_set_match() is called before omap_dm_timer_start(), the value read from OMAP_TIMER_CTRL_REG will be 'wrong' and this wrong value will be stored context.tclr so a subsequent omap_dm_timer_start() can fail (As the control register is wrong). Simplify this be doing the restore-from-context in omap_dm_timer_enable() so that whenever the timer is enabled, the context is correct. Also update the ctx_loss_count at the same time as we notice it is wrong - these is no value in delaying this until the omap_dm_timer_disable() as it cannot change while the timer is enabled. Signed-off-by: NeilBrown [jon-hunter@ti.com: minor update to subject and changed variable name] Signed-off-by: Jon Hunter Acked-by: Tony Lindgren Signed-off-by: Benoit Cousson --- arch/arm/plat-omap/dmtimer.c | 32 ++++++++++++-------------------- 1 file changed, 12 insertions(+), 20 deletions(-) diff --git a/arch/arm/plat-omap/dmtimer.c b/arch/arm/plat-omap/dmtimer.c index a0daa2fb5de..5cae1dd1f36 100644 --- a/arch/arm/plat-omap/dmtimer.c +++ b/arch/arm/plat-omap/dmtimer.c @@ -315,7 +315,19 @@ EXPORT_SYMBOL_GPL(omap_dm_timer_free); void omap_dm_timer_enable(struct omap_dm_timer *timer) { + int c; + pm_runtime_get_sync(&timer->pdev->dev); + + if (!(timer->capability & OMAP_TIMER_ALWON)) { + if (timer->get_context_loss_count) { + c = timer->get_context_loss_count(&timer->pdev->dev); + if (c != timer->ctx_loss_count) { + omap_timer_restore_context(timer); + timer->ctx_loss_count = c; + } + } + } } EXPORT_SYMBOL_GPL(omap_dm_timer_enable); @@ -410,13 +422,6 @@ int omap_dm_timer_start(struct omap_dm_timer *timer) omap_dm_timer_enable(timer); - if (!(timer->capability & OMAP_TIMER_ALWON)) { - if (timer->get_context_loss_count && - timer->get_context_loss_count(&timer->pdev->dev) != - timer->ctx_loss_count) - omap_timer_restore_context(timer); - } - l = omap_dm_timer_read_reg(timer, OMAP_TIMER_CTRL_REG); if (!(l & OMAP_TIMER_CTRL_ST)) { l |= OMAP_TIMER_CTRL_ST; @@ -441,12 +446,6 @@ int omap_dm_timer_stop(struct omap_dm_timer *timer) __omap_dm_timer_stop(timer, timer->posted, rate); - if (!(timer->capability & OMAP_TIMER_ALWON)) { - if (timer->get_context_loss_count) - timer->ctx_loss_count = - timer->get_context_loss_count(&timer->pdev->dev); - } - /* * Since the register values are computed and written within * __omap_dm_timer_stop, we need to use read to retrieve the @@ -553,13 +552,6 @@ int omap_dm_timer_set_load_start(struct omap_dm_timer *timer, int autoreload, omap_dm_timer_enable(timer); - if (!(timer->capability & OMAP_TIMER_ALWON)) { - if (timer->get_context_loss_count && - timer->get_context_loss_count(&timer->pdev->dev) != - timer->ctx_loss_count) - omap_timer_restore_context(timer); - } - l = omap_dm_timer_read_reg(timer, OMAP_TIMER_CTRL_REG); if (autoreload) { l |= OMAP_TIMER_CTRL_AR; -- 2.20.1