ARM: OMAP2+: hwmod: Add a new state to handle hwmods left enabled at init

PATCH Superseded Rajendra Nayak 3 participants 4 messages Nov 21, 2011 – Dec 16, 2011

Subsystems (4)

Arm (32-bit) Arm sub-architectures OMAP2+ support OMAP hwmod support

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Rajendra Nayak

author

2011-11-21 12:12 UTC #0 lore raw

PATCH v3 1/1 ARM: OMAP2+: hwmod: Add a new state to handle hwmods left enabled at init

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 state '_HWMOD_STATE_ENABLED_AT_INIT' 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 and a state change to '_HWMOD_STATE_ENABLED' 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 <[email protected]>

Acked-by Benoit Cousson <[email protected]>

Signed-off-by Rajendra Nayak <[email protected]>

---
 arch/arm/mach-omap2/omap_hwmod.c             |   23 ++++++++++++++++++++++-
 arch/arm/plat-omap/include/plat/omap_hwmod.h |    6 ++++++
 2 files changed, 28 insertions(+), 1 deletions(-)

arch/arm/mach-omap2/omap_hwmod.c +22 -1

index 6b3088d..166a42d 100644
@@ -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 update the state.
+	 */
+	if (oh->_state == _HWMOD_STATE_ENABLED_AT_INIT) {
+		/*
+		 * 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->_state = _HWMOD_STATE_ENABLED;
+		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->_state = _HWMOD_STATE_ENABLED_AT_INIT;
 		postsetup_state = _HWMOD_STATE_ENABLED;
+	}
 
 	if (postsetup_state == _HWMOD_STATE_IDLE)
 		_idle(oh);

arch/arm/plat-omap/include/plat/omap_hwmod.h +6 -0

index 8b372ed..2bd3929 100644
@@ -436,6 +436,12 @@ struct omap_hwmod_omap4_prcm {
 #define _HWMOD_STATE_ENABLED			4
 #define _HWMOD_STATE_IDLE			5
 #define _HWMOD_STATE_DISABLED			6
+/*
+ * This state signifies the hwmod was left enabled
+ * after init, by the framework, because of the
+ * 'HWMOD_INIT_NO_IDLE' flag.
+ */
+#define _HWMOD_STATE_ENABLED_AT_INIT		7
 
 /**
  * struct omap_hwmod_class - the type of an IP block

Signature · 1 line

1.7.1

Kevin Hilman

2011-11-21 18:38 UTC #1 lore raw

PATCH v3 1/1 ARM: OMAP2+: hwmod: Add a new state to handle hwmods left enabled at init

Quoted 14 lines · Rajendra Nayak

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 state '_HWMOD_STATE_ENABLED_AT_INIT' 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 and a state change to '_HWMOD_STATE_ENABLED' 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().

Quoted 7 lines

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 <[email protected]>
Acked-by Benoit Cousson <[email protected]>

Looks like we need a

Tested-by Govindraj Raja <[email protected]>

here as well. Thanks Govindraj for testing.

Quoted 1 line

Signed-off-by Rajendra Nayak <[email protected]>

Kevin

Paul Walmsley

maintainer

2011-12-16 10:37 UTC #2 lore raw

PATCH v3 1/1 ARM: OMAP2+: hwmod: Add a new state to handle hwmods left enabled at init

In reply to Rajendra Nayak

Quoted 14 lines · Rajendra Nayak

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 state '_HWMOD_STATE_ENABLED_AT_INIT' 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 and a state change to '_HWMOD_STATE_ENABLED' 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().

Quoted 8 lines

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 <[email protected]>
Acked-by Benoit Cousson <[email protected]>
Signed-off-by Rajendra Nayak <[email protected]>

I've tweaked this patch a little bit, mostly to avoid adding a new state, which increases the complexity of the rest of the code that handles the hwmod state machine. The modified patch below just uses an internal flag. Please let me know if you have any comments.

- Paul

From: Rajendra Nayak <[email protected]>
Date: Mon, 21 Nov 2011 17:42:50 +0530
Subject: [PATCH] ARM: OMAP2+: hwmod: Add a new flag to handle hwmods left
enabled at init

Fix this by introducing a new internal '_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().

Acked-by Kevin Hilman <[email protected]>

Acked-by Benoit Cousson <[email protected]>

Signed-off-by Rajendra Nayak <[email protected]>

[paul at pwsan.com: use a flag rather than a state; updated commit message;
edited some documentation]

Signed-off-by Paul Walmsley <[email protected]>

---
 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(-)

arch/arm/mach-omap2/omap_hwmod.c +22 -1

index ebace0f..0a89335 100644
@@ -1449,6 +1449,25 @@ 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)
 		_idle(oh);

arch/arm/plat-omap/include/plat/omap_hwmod.h +3 -0

index 8b372ed..1a13c02 100644
@@ -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

Signature · 1 line

1.7.7.3

Rajendra Nayak

author

2011-12-16 11:03 UTC #3 lore raw

PATCH v3 1/1 ARM: OMAP2+: hwmod: Add a new state to handle hwmods left enabled at init

Hi Paul,

Quoted 21 lines · Paul Walmsley

Quoted 19 lines · Rajendra Nayak
Quoted 19 lines
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 state '_HWMOD_STATE_ENABLED_AT_INIT' 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 and a state change to '_HWMOD_STATE_ENABLED' 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.

Quoted 7 lines

Quoted 3 lines
Quoted 3 lines
Acked-by Kevin Hilman<[email protected]>
Acked-by Benoit Cousson<[email protected]>
Signed-off-by Rajendra Nayak<[email protected]>
I've tweaked this patch a little bit, mostly to avoid adding a new state, which increases the complexity of the rest of the code that handles the hwmod state machine. The modified patch below just uses an internal flag. Please let me know if you have any comments.

Looks good to me.

thanks,
Rajendra