linux-kernel - [PATCH 2/3] ARM: OMAP: hwmod: revise deassert sequence

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Date:	Mon, 16 Jul 2012 14:21:24 -0500
From:	Omar Ramirez Luna <omar.luna@...aro.org>
To:	Paul Walmsley <paul@...an.com>
Cc:	Benoit Cousson <b-cousson@...com>,
	Tony Lindgren <tony@...mide.com>,
	Russell King <linux@....linux.org.uk>,
	Kevin Hilman <khilman@...com>,
	Ohad Ben-Cohen <ohad@...ery.com>,
	Tomi Valkeinen <tomi.valkeinen@...com>,
	linux-omap@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	Omar Ramirez Luna <omar.luna@...aro.org>
Subject: [PATCH 2/3] ARM: OMAP: hwmod: revise deassert sequence

For a reset sequence to complete cleanly, a module needs its
associated clocks to be enabled, otherwise the timeout check
in prcm code can print a false failure (failed to hardreset)
that occurs because the clocks aren't powered ON and the status
bit checked can't transition without them.

Signed-off-by: Omar Ramirez Luna <omar.luna@...aro.org>
---
 arch/arm/mach-omap2/omap_hwmod.c |   33 +++++++++++++++++++++++++++++++++
 1 files changed, 33 insertions(+), 0 deletions(-)

diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
index 091c199..f6f8d99 100644
--- a/arch/arm/mach-omap2/omap_hwmod.c
+++ b/arch/arm/mach-omap2/omap_hwmod.c
@@ -1509,6 +1509,7 @@ static int _deassert_hardreset(struct omap_hwmod *oh, const char *name)
 {
 	struct omap_hwmod_rst_info ohri;
 	int ret = -EINVAL;
+	int hwsup = 0;
 
 	if (!oh)
 		return -EINVAL;
@@ -1520,10 +1521,42 @@ static int _deassert_hardreset(struct omap_hwmod *oh, const char *name)
 	if (IS_ERR_VALUE(ret))
 		return ret;
 
+	if (oh->clkdm) {
+		/*
+		 * A clockdomain must be in SW_SUP otherwise reset
+		 * might not be completed. The clockdomain can be set
+		 * in HW_AUTO only when the module become ready.
+		 */
+		hwsup = clkdm_in_hwsup(oh->clkdm);
+		ret = clkdm_hwmod_enable(oh->clkdm, oh);
+		if (ret) {
+			WARN(1, "omap_hwmod: %s: could not enable clockdomain %s: %d\n",
+			     oh->name, oh->clkdm->name, ret);
+			return ret;
+		}
+	}
+
+	_enable_clocks(oh);
+
 	ret = soc_ops.deassert_hardreset(oh, &ohri);
+
+	_disable_clocks(oh);
+
 	if (ret == -EBUSY)
 		pr_warning("omap_hwmod: %s: failed to hardreset\n", oh->name);
 
+	if (!ret) {
+		/*
+		 * Set the clockdomain to HW_AUTO, assuming that the
+		 * previous state was HW_AUTO.
+		 */
+		if (oh->clkdm && hwsup)
+			clkdm_allow_idle(oh->clkdm);
+	} else {
+		if (oh->clkdm)
+			clkdm_hwmod_disable(oh->clkdm, oh);
+	}
+
 	return ret;
 }
 
-- 
1.7.4.1

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