[PATCH v4 7/7] OMAP2+: hwmod: Follow the recommended PRCM module enable sequence

[Benoit Cousson]

From: Rajendra Nayak <rnayak at ti.com>

On OMAP4, the PRCM recommended sequence for enabling
a module after power-on-reset is:
-1- Force clkdm to SW_WKUP
-2- Enabling the clocks
-3- Configure desired module mode to "enable" or "auto"
-4- Wait for the desired module idle status to be FUNC
-5- Program clkdm in HW_AUTO(if supported)

This sequence applies to all older OMAPs' as well,
however since they use autodeps, it makes sure that
no clkdm is in IDLE, and hence not requiring a force
SW_WKUP when a module is being enabled.

OMAP4 does not need to support autodeps, because
of the dyanamic dependency feature, wherein
the HW takes care of waking up a clockdomain from
idle and hence the module, whenever an interconnect
access happens to the given module.

Implementing the sequence for OMAP4 requires
the clockdomain handling that is currently done in
clock framework to be done as part of hwmod framework
since the step -4- above to "Wait for the desired
module idle status to be FUNC" is done as part of
hwmod framework.

Signed-off-by: Rajendra Nayak <rnayak at ti.com>
[b-cousson at ti.com: Adapt it to the new clkdm hwmod attribute and API]
Signed-off-by: Benoit Cousson <b-cousson at ti.com>
Cc: Paul Walmsley <paul at pwsan.com>
---
 arch/arm/mach-omap2/clock.c      |   17 +----------------
 arch/arm/mach-omap2/omap_hwmod.c |   25 +++++++++++++++++++++++++
 2 files changed, 26 insertions(+), 16 deletions(-)

diff --git a/arch/arm/mach-omap2/clock.c b/arch/arm/mach-omap2/clock.c
index 180299e..2828d29 100644
--- a/arch/arm/mach-omap2/clock.c
+++ b/arch/arm/mach-omap2/clock.c
@@ -268,9 +268,6 @@ void omap2_clk_disable(struct clk *clk)
 		clk->ops->disable(clk);
 	}
 
-	if (clk->clkdm)
-		clkdm_clk_disable(clk->clkdm, clk);
-
 	if (clk->parent)
 		omap2_clk_disable(clk->parent);
 }
@@ -308,30 +305,18 @@ int omap2_clk_enable(struct clk *clk)
 		}
 	}
 
-	if (clk->clkdm) {
-		ret = clkdm_clk_enable(clk->clkdm, clk);
-		if (ret) {
-			WARN(1, "clock: %s: could not enable clockdomain %s: "
-			     "%d\n", clk->name, clk->clkdm->name, ret);
-			goto oce_err2;
-		}
-	}
-
 	if (clk->ops && clk->ops->enable) {
 		trace_clock_enable(clk->name, 1, smp_processor_id());
 		ret = clk->ops->enable(clk);
 		if (ret) {
 			WARN(1, "clock: %s: could not enable: %d\n",
 			     clk->name, ret);
-			goto oce_err3;
+			goto oce_err2;
 		}
 	}
 
 	return 0;
 
-oce_err3:
-	if (clk->clkdm)
-		clkdm_clk_disable(clk->clkdm, clk);
 oce_err2:
 	if (clk->parent)
 		omap2_clk_disable(clk->parent);
diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
index 117a4d5..3d7a37e 100644
--- a/arch/arm/mach-omap2/omap_hwmod.c
+++ b/arch/arm/mach-omap2/omap_hwmod.c
@@ -1362,6 +1362,7 @@ static int _reset(struct omap_hwmod *oh)
 static int _enable(struct omap_hwmod *oh)
 {
 	int r;
+	int hwsup = 0;
 
 	pr_debug("omap_hwmod: %s: enabling\n", oh->name);
 
@@ -1380,6 +1381,19 @@ static int _enable(struct omap_hwmod *oh)
 		omap_hwmod_mux(oh->mux, _HWMOD_STATE_ENABLED);
 
 	_add_initiator_dep(oh, mpu_oh);
+
+	/*
+	 * A clockdomain must be in SW_SUP before enabling completely the
+	 * module. The clockdomain can be set in HW_AUTO only when the module
+	 * become ready.
+	 */
+	hwsup = clkdm_allows_idle(oh->clkdm);
+	r = clkdm_hwmod_enable(oh->clkdm, oh);
+	if (r) {
+		WARN(1, "omap_hwmod: %s: could not enable clockdomain %s: %d\n",
+		     oh->name, oh->clkdm->name, r);
+		return r;
+	}
 	_enable_clocks(oh);
 	_enable_module(oh);
 
@@ -1396,11 +1410,20 @@ static int _enable(struct omap_hwmod *oh)
 	if (r) {
 		pr_debug("omap_hwmod: %s: _wait_target_ready: %d\n",
 			 oh->name, r);
+
 		_disable_clocks(oh);
+		clkdm_hwmod_disable(oh->clkdm, oh);
 
 		return r;
 	}
 
+	/*
+	 * Set the clockdomain to HW_AUTO only if the target is ready,
+	 * assuming that the previous state was HW_AUTO
+	 */
+	if (hwsup)
+		clkdm_allow_idle(oh->clkdm);
+
 	oh->_state = _HWMOD_STATE_ENABLED;
 
 	/* Access the sysconfig only if the target is ready */
@@ -1448,6 +1471,7 @@ static int _idle(struct omap_hwmod *oh)
 	 * transition to complete properly.
 	 */
 	_disable_clocks(oh);
+	clkdm_hwmod_disable(oh->clkdm, oh);
 
 	/* Mux pins for device idle if populated */
 	if (oh->mux && oh->mux->pads_dynamic)
@@ -1545,6 +1569,7 @@ static int _shutdown(struct omap_hwmod *oh)
 			pr_debug("omap_hwmod: %s: _wait_target_disable failed\n",
 				   oh->name);
 		_disable_clocks(oh);
+		clkdm_hwmod_disable(oh->clkdm, oh);
 	}
 	/* XXX Should this code also force-disable the optional clocks? */
 
-- 
1.7.0.4