Benoit Cousson <[email protected]> writes:
> From: Rajendra Nayak <[email protected]>
>
> 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 <[email protected]>
> [[email protected]: Adapt it to the new clkdm hwmod attribute and API]
> Signed-off-by: Benoit Cousson <[email protected]>
> Cc: Paul Walmsley <[email protected]>
[...]
> diff --git a/arch/arm/mach-omap2/omap_hwmod.c
> b/arch/arm/mach-omap2/omap_hwmod.c
> index 3eef106..3538805 100644
> --- a/arch/arm/mach-omap2/omap_hwmod.c
> +++ b/arch/arm/mach-omap2/omap_hwmod.c
> @@ -1360,6 +1360,7 @@ static int _reset(struct omap_hwmod *oh)
> static int _enable(struct omap_hwmod *oh)
> {
> int r;
> + int hwsup = 0;
>
> if (oh->_state != _HWMOD_STATE_INITIALIZED &&
> oh->_state != _HWMOD_STATE_IDLE &&
> @@ -1378,6 +1379,19 @@ static int _enable(struct omap_hwmod *oh)
> omap_hwmod_mux(oh->mux, _HWMOD_STATE_ENABLED);
>
> _add_initiator_dep(oh, mpu_oh);
> +
> + /*
> + * 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_allows_idle(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;
> + }
If oh->clkdm == NULL (as it is on OMAP3 since the hwmod data has no
clkdms yet), this hangs trying to dereference oh->clkdm->name.
Simple fix below, but probably better is to not call any of these
functions if oh->clkdm == NULL, otherwise this is very noisy on OMAP3
since that WARN is printed for every hwmod.
Is anyone planning to add the clkdms to OMAP3 hwmod data?
Kevin
diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
index 51a13f3..4bcffca 100644
--- a/arch/arm/mach-omap2/omap_hwmod.c
+++ b/arch/arm/mach-omap2/omap_hwmod.c
@@ -1391,9 +1391,10 @@ static int _enable(struct omap_hwmod *oh)
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);
+ oh->name, oh->clkdm ? oh->clkdm->name : "none", r);
return r;
}
+
_enable_clocks(oh);
_enable_module(oh);
--
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