[PATCH] ARM: omap_hwmod: Add a new state to handle hwmods left enabled at init

[Rajendra Nayak]

A 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 hmwod framework throws a WARN() about
the device being already in enabled state.

Fix this by introducing a new state '_HWMOD_STATE_ENABLED_AT_INIT'
to identify such devices/hwmods, so nothing but just a state
change to '_HWMOD_STATE_ENABLED' can be done when the device/hwmod
is requested to be enabled (the first time) by its driver/user.

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.

Signed-off-by: Rajendra Nayak <rnayak at ti.com>
---
 arch/arm/mach-omap2/omap_hwmod.c             |   16 ++++++++++++++--
 arch/arm/plat-omap/include/plat/omap_hwmod.h |    1 +
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
index d7f4623..7d94cc3 100644
--- a/arch/arm/mach-omap2/omap_hwmod.c
+++ b/arch/arm/mach-omap2/omap_hwmod.c
@@ -1441,6 +1441,17 @@ 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 update the state.
+	 */
+	if (oh->_state == _HWMOD_STATE_ENABLED_AT_INIT) {
+		oh->_state = _HWMOD_STATE_ENABLED;
+		return 0;
+	}
+
 	if (oh->_state != _HWMOD_STATE_INITIALIZED &&
 	    oh->_state != _HWMOD_STATE_IDLE &&
 	    oh->_state != _HWMOD_STATE_DISABLED) {
@@ -1449,7 +1460,6 @@ static int _enable(struct omap_hwmod *oh)
 		return -EINVAL;
 	}
 
-
 	/*
 	 * If an IP contains only one HW reset line, then de-assert it in order
 	 * to allow the module state transition. Otherwise the PRCM will return
@@ -1744,8 +1754,10 @@ 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->_state = _HWMOD_STATE_ENABLED_AT_INIT;
 		postsetup_state = _HWMOD_STATE_ENABLED;
+	}
 
 	if (postsetup_state == _HWMOD_STATE_IDLE)
 		_idle(oh);
diff --git a/arch/arm/plat-omap/include/plat/omap_hwmod.h b/arch/arm/plat-omap/include/plat/omap_hwmod.h
index 1b81dfb..cd49d60 100644
--- a/arch/arm/plat-omap/include/plat/omap_hwmod.h
+++ b/arch/arm/plat-omap/include/plat/omap_hwmod.h
@@ -436,6 +436,7 @@ struct omap_hwmod_omap4_prcm {
 #define _HWMOD_STATE_ENABLED			4
 #define _HWMOD_STATE_IDLE			5
 #define _HWMOD_STATE_DISABLED			6
+#define _HWMOD_STATE_ENABLED_AT_INIT		7
 
 /**
  * struct omap_hwmod_class - the type of an IP block
-- 
1.7.1