diff mbox

[2/2] ARM: OMAP: hwmod: revise deassert sequence

Message ID 1345614150-25723-3-git-send-email-omar.luna@linaro.org (mailing list archive)
State New, archived
Headers show

Commit Message

Omar Ramirez Luna Aug. 22, 2012, 5:42 a.m. UTC
For a reset sequence to complete cleanly, a module needs its
associated clocks to be enabled, otherwise the timeout check
in prcm code can print a false failure (failed to hardreset)
that occurs because the clocks aren't powered ON and the status
bit checked can't transition without them.

Signed-off-by: Omar Ramirez Luna <omar.luna@linaro.org>
---
 arch/arm/mach-omap2/omap_hwmod.c |   37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

Comments

Benoit Cousson Sept. 6, 2012, 3:12 p.m. UTC | #1
Hi Omar,

On 08/22/2012 07:42 AM, Omar Ramirez Luna wrote:
> For a reset sequence to complete cleanly, a module needs its
> associated clocks to be enabled, otherwise the timeout check
> in prcm code can print a false failure (failed to hardreset)
> that occurs because the clocks aren't powered ON and the status
> bit checked can't transition without them.
> 
> Signed-off-by: Omar Ramirez Luna <omar.luna@linaro.org>
> ---
>  arch/arm/mach-omap2/omap_hwmod.c |   37 +++++++++++++++++++++++++++++++++++++
>  1 file changed, 37 insertions(+)
> 
> diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
> index eaedc33..b65e021 100644
> --- a/arch/arm/mach-omap2/omap_hwmod.c
> +++ b/arch/arm/mach-omap2/omap_hwmod.c
> @@ -1509,6 +1509,7 @@ static int _deassert_hardreset(struct omap_hwmod *oh, const char *name)
>  {
>  	struct omap_hwmod_rst_info ohri;
>  	int ret = -EINVAL;
> +	int hwsup = 0;
>  
>  	if (!oh)
>  		return -EINVAL;
> @@ -1520,10 +1521,46 @@ static int _deassert_hardreset(struct omap_hwmod *oh, const char *name)
>  	if (IS_ERR_VALUE(ret))
>  		return ret;
>  
> +	if (oh->clkdm) {
> +		/*
> +		 * A clockdomain must be in SW_SUP otherwise reset
> +		 * might not be completed. The clockdomain can be set
> +		 * in HW_AUTO only when the module become ready.
> +		 */
> +		hwsup = clkdm_in_hwsup(oh->clkdm);
> +		ret = clkdm_hwmod_enable(oh->clkdm, oh);
> +		if (ret) {> 

> +			WARN(1, "omap_hwmod: %s: could not enable clockdomain %s: %d\n",
> +			     oh->name, oh->clkdm->name, ret);
> +			return ret;
> +		}
> +	}
> +
> +	_enable_clocks(oh);
> +	if (soc_ops.enable_module)
> +		soc_ops.enable_module(oh);
> +
>  	ret = soc_ops.deassert_hardreset(oh, &ohri);
> +
> +	if (soc_ops.disable_module)
> +		soc_ops.disable_module(oh);
> +	_disable_clocks(oh);
> +
>  	if (ret == -EBUSY)
>  		pr_warning("omap_hwmod: %s: failed to hardreset\n", oh->name);
>  
> +	if (!ret) {
> +		/*
> +		 * Set the clockdomain to HW_AUTO, assuming that the
> +		 * previous state was HW_AUTO.
> +		 */
> +		if (oh->clkdm && hwsup)
> +			clkdm_allow_idle(oh->clkdm);
> +	} else {
> +		if (oh->clkdm)
> +			clkdm_hwmod_disable(oh->clkdm, oh);
> +	}
> +
>  	return ret;
>  }
>  

The sequence is good, I'm just a little bit concern about the
duplication of code compared to _enable sequence.

That being said, this is the consequence of removing the hardreset
sequence outside of the main _enable/_shutdown sequence.

So I'm not sure I have any better way of doing that :-(

Regards,
Benoit

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Omar Ramirez Luna Sept. 10, 2012, 5:14 p.m. UTC | #2
Hi Benoit,

On 6 September 2012 10:12, Benoit Cousson <b-cousson@ti.com> wrote:
> The sequence is good, I'm just a little bit concern about the
> duplication of code compared to _enable sequence.
>
> That being said, this is the consequence of removing the hardreset
> sequence outside of the main _enable/_shutdown sequence.
>
> So I'm not sure I have any better way of doing that :-(

Indeed, it should be exactly the same as putting back the reset
sequence into _enable/_shutdown, so with these patches I was expecting
we could gather the hard reset users and see if they needed anything
else beyond these functions, if not, perhaps just put back the reset
code into _enable/_shutdown paths.

Thanks,

Omar
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Paul Walmsley Sept. 21, 2012, 12:45 a.m. UTC | #3
Hi

On Wed, 22 Aug 2012, Omar Ramirez Luna wrote:

> For a reset sequence to complete cleanly, a module needs its
> associated clocks to be enabled, otherwise the timeout check
> in prcm code can print a false failure (failed to hardreset)
> that occurs because the clocks aren't powered ON and the status
> bit checked can't transition without them.
> 
> Signed-off-by: Omar Ramirez Luna <omar.luna@linaro.org>

Queued for 3.7, with the same caveats mentioned regarding patch 1.


- Paul
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diff mbox

Patch

diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
index eaedc33..b65e021 100644
--- a/arch/arm/mach-omap2/omap_hwmod.c
+++ b/arch/arm/mach-omap2/omap_hwmod.c
@@ -1509,6 +1509,7 @@  static int _deassert_hardreset(struct omap_hwmod *oh, const char *name)
 {
 	struct omap_hwmod_rst_info ohri;
 	int ret = -EINVAL;
+	int hwsup = 0;
 
 	if (!oh)
 		return -EINVAL;
@@ -1520,10 +1521,46 @@  static int _deassert_hardreset(struct omap_hwmod *oh, const char *name)
 	if (IS_ERR_VALUE(ret))
 		return ret;
 
+	if (oh->clkdm) {
+		/*
+		 * A clockdomain must be in SW_SUP otherwise reset
+		 * might not be completed. The clockdomain can be set
+		 * in HW_AUTO only when the module become ready.
+		 */
+		hwsup = clkdm_in_hwsup(oh->clkdm);
+		ret = clkdm_hwmod_enable(oh->clkdm, oh);
+		if (ret) {
+			WARN(1, "omap_hwmod: %s: could not enable clockdomain %s: %d\n",
+			     oh->name, oh->clkdm->name, ret);
+			return ret;
+		}
+	}
+
+	_enable_clocks(oh);
+	if (soc_ops.enable_module)
+		soc_ops.enable_module(oh);
+
 	ret = soc_ops.deassert_hardreset(oh, &ohri);
+
+	if (soc_ops.disable_module)
+		soc_ops.disable_module(oh);
+	_disable_clocks(oh);
+
 	if (ret == -EBUSY)
 		pr_warning("omap_hwmod: %s: failed to hardreset\n", oh->name);
 
+	if (!ret) {
+		/*
+		 * Set the clockdomain to HW_AUTO, assuming that the
+		 * previous state was HW_AUTO.
+		 */
+		if (oh->clkdm && hwsup)
+			clkdm_allow_idle(oh->clkdm);
+	} else {
+		if (oh->clkdm)
+			clkdm_hwmod_disable(oh->clkdm, oh);
+	}
+
 	return ret;
 }