[PATCH v4] ARM: OMAP2+: hwmod: Add a new flag to handle hwmods left enabled at init

Paul Walmsley paul at pwsan.com
Fri Dec 16 07:50:12 EST 2011

From: Rajendra Nayak <rnayak at ti.com>

An hwmod with a 'HWMOD_INIT_NO_IDLE' flag set, is left in
enabled state by the hwmod framework post the initial setup.
Once a real user of the device (a driver) tries to enable it
at a later point, the hwmod framework throws a WARN() about
the device being already in enabled state.

Fix this by introducing a new internal flag '_HWMOD_SKIP_ENABLE' to
identify such devices/hwmods. When the device/hwmod is requested to be
enabled (the first time) by its driver/user, nothing except the
mux-enable is needed. The mux data is board specific and is
unavailable during initial enable() of the device, done by the
framework as part of setup().

A good example of a such a device is an UART used as debug console.
The UART module needs to be kept enabled through the boot, until the
UART driver takes control of it, for debug prints to appear on
the console.

Acked-by: Kevin Hilman <khilman at ti.com>
Acked-by: Benoit Cousson <b-cousson at ti.com>
Signed-off-by: Rajendra Nayak <rnayak at ti.com>
[paul at pwsan.com: use a flag rather than a state; updated commit message;
 edited some documentation]
Signed-off-by: Paul Walmsley <paul at pwsan.com>

This patch needs to be applied along with Govindraj & Kevin's  UART
patch set.  Otherwise lots of nasty warnings are generated to the console
during boot.  Applies on top of v3.2-rc5.

 arch/arm/mach-omap2/omap_hwmod.c             |   23 ++++++++++++++++++++++-
 arch/arm/plat-omap/include/plat/omap_hwmod.h |    3 +++
 2 files changed, 25 insertions(+), 1 deletions(-)

diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
index 529142a..f673f80 100644
--- a/arch/arm/mach-omap2/omap_hwmod.c
+++ b/arch/arm/mach-omap2/omap_hwmod.c
@@ -1441,6 +1441,25 @@ static int _enable(struct omap_hwmod *oh)
 	pr_debug("omap_hwmod: %s: enabling\n", oh->name);
+	/*
+	 * hwmods with HWMOD_INIT_NO_IDLE flag set are left
+	 * in enabled state at init.
+	 * Now that someone is really trying to enable them,
+	 * just ensure that the hwmod mux is set.
+	 */
+	if (oh->_int_flags & _HWMOD_SKIP_ENABLE) {
+		/*
+		 * If the caller has mux data populated, do the mux'ing
+		 * which wouldn't have been done as part of the _enable()
+		 * done during setup.
+		 */
+		if (oh->mux)
+			omap_hwmod_mux(oh->mux, _HWMOD_STATE_ENABLED);
+		oh->_int_flags &= ~_HWMOD_SKIP_ENABLE;
+		return 0;
+	}
 	if (oh->_state != _HWMOD_STATE_INITIALIZED &&
 	    oh->_state != _HWMOD_STATE_IDLE &&
 	    oh->_state != _HWMOD_STATE_DISABLED) {
@@ -1744,8 +1763,10 @@ static int _setup(struct omap_hwmod *oh, void *data)
 	 * it should be set by the core code as a runtime flag during startup
 	if ((oh->flags & HWMOD_INIT_NO_IDLE) &&
-	    (postsetup_state == _HWMOD_STATE_IDLE))
+	    (postsetup_state == _HWMOD_STATE_IDLE)) {
+		oh->_int_flags |= _HWMOD_SKIP_ENABLE;
 		postsetup_state = _HWMOD_STATE_ENABLED;
+	}
 	if (postsetup_state == _HWMOD_STATE_IDLE)
diff --git a/arch/arm/plat-omap/include/plat/omap_hwmod.h b/arch/arm/plat-omap/include/plat/omap_hwmod.h
index 8b372ed..1a13c02 100644
--- a/arch/arm/plat-omap/include/plat/omap_hwmod.h
+++ b/arch/arm/plat-omap/include/plat/omap_hwmod.h
@@ -416,10 +416,13 @@ struct omap_hwmod_omap4_prcm {
  * _HWMOD_NO_MPU_PORT: no path exists for the MPU to write to this module
  * _HWMOD_WAKEUP_ENABLED: set when the omap_hwmod code has enabled ENAWAKEUP
  * _HWMOD_SYSCONFIG_LOADED: set when the OCP_SYSCONFIG value has been cached
+ * _HWMOD_SKIP_ENABLE: set if hwmod enabled during init (HWMOD_INIT_NO_IDLE) -
+ *     causes the first call to _enable() to only update the pinmux
 #define _HWMOD_NO_MPU_PORT			(1 << 0)
 #define _HWMOD_WAKEUP_ENABLED			(1 << 1)
 #define _HWMOD_SYSCONFIG_LOADED			(1 << 2)
+#define _HWMOD_SKIP_ENABLE			(1 << 3)
  * omap_hwmod._state definitions

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