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

+ Paul

On 11/17/2011 11:11 AM, Rajendra Nayak wrote:

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

typo: -------------------^

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 Nayakrnayak@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
  

Is the ' needed here? But I'm not an expert in English grammar...

• * 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; }

Not related to the patch changelog but that make senses to do it, so just update the changelog.

/* * 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

You should update the comment before... yeah I know, the other states are not documented, but they are much more understandable than this new one.

/**

• struct omap_hwmod_class - the type of an IP block

+1 Looks good to me but someone else must approve... Oops, sorry its not Gerrit :-)

Acked-by: Benoit Cousson b-cousson@ti.com

Thanks, Benoit