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OMAP2+: hwmod: Follow the recommended PRCM module enable sequence 

On OMAP4, the PRCM recommended sequence for enabling
a module after power-on-reset is:
-1- Force clkdm to SW_WKUP
-2- Enabling the clocks
-3- Configure desired module mode to "enable" or "auto"
-4- Wait for the desired module idle status to be FUNC
-5- Program clkdm in HW_AUTO(if supported)

This sequence applies to all older OMAPs' as well,
however since they use autodeps, it makes sure that
no clkdm is in IDLE, and hence not requiring a force
SW_WKUP when a module is being enabled.

OMAP4 does not need to support autodeps, because
of the dyanamic dependency feature, wherein
the HW takes care of waking up a clockdomain from
idle and hence the module, whenever an interconnect
access happens to the given module.

Implementing the sequence for OMAP4 requires
the clockdomain handling that is currently done in
clock framework to be done as part of hwmod framework
since the step -4- above to "Wait for the desired
module idle status to be FUNC" is done as part of
hwmod framework.

Signed-off-by: Rajendra Nayak <rnayak@ti.com>
[b-cousson@ti.com: Adapt it to the new clkdm hwmod attribute and API]
Signed-off-by: Benoit Cousson <b-cousson@ti.com>
Cc: Paul Walmsley <paul@pwsan.com>
[paul@pwsan.com: dropped mach-omap2/clock.c changes; modified to only
 call the clockdomain code if oh->clkdm is set; disable clock->clockdomain
 interaction on OMAP4]
Signed-off-by: Paul Walmsley <paul@pwsan.com>
This commit is contained in:
Rajendra Nayak 2011-07-10 05:57:07 -06:00 committed by Paul Walmsley
parent 12706c5425
commit 665d001338
2 changed files with 51 additions and 20 deletions
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1
arch/arm/mach-omap2/clock44xx_data.c
View File

@ -3212,6 +3212,7 @@ int __init omap4xxx_clk_init(void)
}
clk_init(&omap2_clk_functions);
omap2_clk_disable_clkdm_control();
for (c = omap44xx_clks; c < omap44xx_clks + ARRAY_SIZE(omap44xx_clks);
c++)

56
arch/arm/mach-omap2/omap_hwmod.c
View File

@ -1437,6 +1437,7 @@ static int _reset(struct omap_hwmod *oh)
static int _enable(struct omap_hwmod *oh)
{
int r;
int hwsup = 0;
pr_debug("omap_hwmod: %s: enabling\n", oh->name);
@ -1448,14 +1449,6 @@ static int _enable(struct omap_hwmod *oh)
return -EINVAL;
}
/* Mux pins for device runtime if populated */
if (oh->mux && (!oh->mux->enabled ||
((oh->_state == _HWMOD_STATE_IDLE) &&
oh->mux->pads_dynamic)))
omap_hwmod_mux(oh->mux, _HWMOD_STATE_ENABLED);
_add_initiator_dep(oh, mpu_oh);
_enable_clocks(oh);
/*
* If an IP contains only one HW reset line, then de-assert it in order
@ -1466,16 +1459,41 @@ static int _enable(struct omap_hwmod *oh)
oh->_state == _HWMOD_STATE_DISABLED) && oh->rst_lines_cnt == 1)
_deassert_hardreset(oh, oh->rst_lines[0].name);
r = _wait_target_ready(oh);
if (r) {
pr_debug("omap_hwmod: %s: _wait_target_ready: %d\n",
oh->name, r);
_disable_clocks(oh);
/* Mux pins for device runtime if populated */
if (oh->mux && (!oh->mux->enabled ||
((oh->_state == _HWMOD_STATE_IDLE) &&
oh->mux->pads_dynamic)))
omap_hwmod_mux(oh->mux, _HWMOD_STATE_ENABLED);
_add_initiator_dep(oh, mpu_oh);
if (oh->clkdm) {
/*
* A clockdomain must be in SW_SUP before enabling
* completely the module. The clockdomain can be set
* in HW_AUTO only when the module become ready.
*/
hwsup = clkdm_in_hwsup(oh->clkdm);
r = clkdm_hwmod_enable(oh->clkdm, oh);
if (r) {
WARN(1, "omap_hwmod: %s: could not enable clockdomain %s: %d\n",
oh->name, oh->clkdm->name, r);
return r;
}
}
_enable_clocks(oh);
_enable_module(oh);
r = _wait_target_ready(oh);
if (!r) {
/*
* Set the clockdomain to HW_AUTO only if the target is ready,
* assuming that the previous state was HW_AUTO
*/
if (oh->clkdm && hwsup)
clkdm_allow_idle(oh->clkdm);
oh->_state = _HWMOD_STATE_ENABLED;
/* Access the sysconfig only if the target is ready */
@ -1484,6 +1502,14 @@ static int _enable(struct omap_hwmod *oh)
_update_sysc_cache(oh);
_enable_sysc(oh);
}
} else {
_disable_clocks(oh);
pr_debug("omap_hwmod: %s: _wait_target_ready: %d\n",
oh->name, r);
if (oh->clkdm)
clkdm_hwmod_disable(oh->clkdm, oh);
}
return r;
}
@ -1523,6 +1549,8 @@ static int _idle(struct omap_hwmod *oh)
* transition to complete properly.
*/
_disable_clocks(oh);
if (oh->clkdm)
clkdm_hwmod_disable(oh->clkdm, oh);
/* Mux pins for device idle if populated */
if (oh->mux && oh->mux->pads_dynamic)
@ -1620,6 +1648,8 @@ static int _shutdown(struct omap_hwmod *oh)
pr_warn("omap_hwmod: %s: _wait_target_disable failed\n",
oh->name);
_disable_clocks(oh);
if (oh->clkdm)
clkdm_hwmod_disable(oh->clkdm, oh);
}
/* XXX Should this code also force-disable the optional clocks? */