[RFC 0/2] OMAP2+: Convert hwmod to do clock inits and reset when drivers initialize

[RFC 0/2] OMAP2+: Convert hwmod to do clock inits and reset when drivers initialize

[Rajendra Nayak]

hwmod framework today does a module enable/reset/idle for all hwmods registered
for a platform quite early at boot.

This has a few downsides like
-1- An early crash failing to enable/reset a device/module needs earlyprintk
for anyone to see the crash logs
-2- Puts a dependency to have all PM frameworks initialized and ready quite
early which inturn prevents some of these to be converted to be independent
drivers

This RFC is an attempt to remove some of these dependencies and do the
hwmod inits (which need other PM frameworks) and resets when the module
is first enabled.

For modules which never get enabled through the boot, there is late call
to do the inits and resets for rest of those modules.

I have been experimenting with some of these on my omap4 panda es and that
boots fine with these patches. If the approach looks fine I will continue
to work some more in this direction and get rid of the early timer need for
hwmod and other PM frameworks.

Rajendra Nayak (2):
  ARM: OMAP2+: hwmod: Split _init() into _init_early() and _init_late()
  ARM: OMAP2+: hwmod: Do the late part of init and setup/reset on first
    enable

 arch/arm/mach-omap2/omap_hwmod.c |   47 +++++++++++++++++++++++++++++++++-----
 1 file changed, 41 insertions(+), 6 deletions(-)

-- 
1.7.9.5

[RFC 1/2] ARM: OMAP2+: hwmod: Split _init() into _init_early() and _init_late()

[Rajendra Nayak]

Split the _init() function into something that can be done early and
the rest which can be done late (during drivers inits).

This is done in preperation to remove the hwmod dependency to do all
clock inits (which inturn need clockdomain and other frameworks to be
in place) and module resets quite early in boot, and instead do these
on demand when the drivers initialize.

Signed-off-by: Rajendra Nayak <rnayak@ti.com>
---
 arch/arm/mach-omap2/omap_hwmod.c |   17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
index 7341eff..e49159c 100644
--- a/arch/arm/mach-omap2/omap_hwmod.c
+++ b/arch/arm/mach-omap2/omap_hwmod.c
@@ -2415,16 +2415,21 @@ static void __init _init_mpu_rt_base(struct omap_hwmod *oh, void *data)
  * upon success or if the hwmod isn't registered, or -EINVAL upon
  * failure.
  */
-static int __init _init(struct omap_hwmod *oh, void *data)
+static int __init _init_early(struct omap_hwmod *oh, void *data)
 {
-	int r;
-
 	if (oh->_state != _HWMOD_STATE_REGISTERED)
 		return 0;
 
 	if (oh->class->sysc)
 		_init_mpu_rt_base(oh, NULL);
 
+	return 0;
+}
+
+static int __init _init_late(struct omap_hwmod *oh, void *data)
+{
+	int r;
+
 	r = _init_clocks(oh, NULL);
 	if (r < 0) {
 		WARN(1, "omap_hwmod: %s: couldn't init clocks\n", oh->name);
@@ -3284,7 +3289,8 @@ int __init omap_hwmod_setup_one(const char *oh_name)
 
 	_ensure_mpu_hwmod_is_setup(oh);
 
-	_init(oh, NULL);
+	_init_early(oh, NULL);
+	_init_late(oh, NULL);
 	_setup(oh, NULL);
 
 	return 0;
@@ -3302,7 +3308,8 @@ static int __init omap_hwmod_setup_all(void)
 {
 	_ensure_mpu_hwmod_is_setup(NULL);
 
-	omap_hwmod_for_each(_init, NULL);
+	omap_hwmod_for_each(_init_early, NULL);
+	omap_hwmod_for_each(_init_late, NULL);
 	omap_hwmod_for_each(_setup, NULL);
 
 	return 0;
-- 
1.7.9.5

[RFC 2/2] ARM: OMAP2+: hwmod: Do the late part of init and setup/reset on first enable

[Rajendra Nayak]

Instead of doing a complete init and setup(including reset) of all modules
early at boot, do it when a module is asked to be enabled the first time.
This should get rid of all the need for having all the rest of PM frameworks
in place quite early at boot, and should also make sure reset happens only
when drivers are initializing the modules.

For the modules which do not have drivers build in, do this as part of a
late initcall.

Signed-off-by: Rajendra Nayak <rnayak@ti.com>
---
 arch/arm/mach-omap2/omap_hwmod.c |   32 ++++++++++++++++++++++++++++++--
 1 file changed, 30 insertions(+), 2 deletions(-)

diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
index e49159c..7e4d602 100644
--- a/arch/arm/mach-omap2/omap_hwmod.c
+++ b/arch/arm/mach-omap2/omap_hwmod.c
@@ -2082,6 +2082,9 @@ static int _enable_preprogram(struct omap_hwmod *oh)
 	return oh->class->enable_preprogram(oh);
 }
 
+static int _init_late(struct omap_hwmod *oh, void *data);
+static void _setup_iclk_autoidle(struct omap_hwmod *oh);
+
 /**
  * _enable - enable an omap_hwmod
  * @oh: struct omap_hwmod *
@@ -2094,9 +2097,17 @@ static int _enable(struct omap_hwmod *oh)
 {
 	int r;
 	int hwsup = 0;
+	bool needs_reset;
 
 	pr_debug("omap_hwmod: %s: enabling\n", oh->name);
 
+	if (oh->_state == _HWMOD_STATE_REGISTERED) {
+		_init_late(oh, NULL);
+		_setup_iclk_autoidle(oh);
+		if (!(oh->flags & HWMOD_INIT_NO_RESET))
+			needs_reset = true;
+	}
+
 	/*
 	 * hwmods with HWMOD_INIT_NO_IDLE flag set are left in enabled
 	 * state at init.  Now that someone is really trying to enable
@@ -2200,6 +2211,9 @@ static int _enable(struct omap_hwmod *oh)
 			clkdm_hwmod_disable(oh->clkdm, oh);
 	}
 
+	if (needs_reset)
+		r = _reset(oh);
+
 	return r;
 }
 
@@ -3309,13 +3323,27 @@ static int __init omap_hwmod_setup_all(void)
 	_ensure_mpu_hwmod_is_setup(NULL);
 
 	omap_hwmod_for_each(_init_early, NULL);
-	omap_hwmod_for_each(_init_late, NULL);
-	omap_hwmod_for_each(_setup, NULL);
 
 	return 0;
 }
 omap_core_initcall(omap_hwmod_setup_all);
 
+static int __init omap_hwmod_setup_rest(void)
+{
+	struct omap_hwmod *oh;
+
+	_ensure_mpu_hwmod_is_setup(NULL);
+
+	list_for_each_entry(oh, &omap_hwmod_list, node) {
+		if (oh->_state == _HWMOD_STATE_REGISTERED) {
+			_init_late(oh, NULL);
+			_setup(oh, NULL);
+		}
+	}
+	return 0;
+}
+omap_late_initcall(omap_hwmod_setup_rest);
+
 /**
  * omap_hwmod_enable - enable an omap_hwmod
  * @oh: struct omap_hwmod *
-- 
1.7.9.5