diff mbox series

[1/2] drm/meson: dw-hdmi: Disable clocks on driver teardown

Message ID 20201120094205.525228-2-maz@kernel.org (mailing list archive)
State New, archived
Delegated to: Neil Armstrong
Headers show
Series More meson HDMI fixes | expand

Commit Message

Marc Zyngier Nov. 20, 2020, 9:42 a.m. UTC
The HDMI driver request clocks early, but never disable them, leaving
the clocks on even when the driver is removed.

Fix it by slightly refactoring the clock code, and register a devm
action that will eventually disable/unprepare the enabled clocks.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 drivers/gpu/drm/meson/meson_dw_hdmi.c | 43 ++++++++++++++++++---------
 1 file changed, 29 insertions(+), 14 deletions(-)

Comments

Neil Armstrong Nov. 20, 2020, 12:26 p.m. UTC | #1
On 20/11/2020 10:42, Marc Zyngier wrote:
> The HDMI driver request clocks early, but never disable them, leaving
> the clocks on even when the driver is removed.
> 
> Fix it by slightly refactoring the clock code, and register a devm
> action that will eventually disable/unprepare the enabled clocks.
> 
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> ---
>  drivers/gpu/drm/meson/meson_dw_hdmi.c | 43 ++++++++++++++++++---------
>  1 file changed, 29 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/gpu/drm/meson/meson_dw_hdmi.c b/drivers/gpu/drm/meson/meson_dw_hdmi.c
> index 7f8eea494147..29623b309cb1 100644
> --- a/drivers/gpu/drm/meson/meson_dw_hdmi.c
> +++ b/drivers/gpu/drm/meson/meson_dw_hdmi.c
> @@ -145,8 +145,6 @@ struct meson_dw_hdmi {
>  	struct reset_control *hdmitx_apb;
>  	struct reset_control *hdmitx_ctrl;
>  	struct reset_control *hdmitx_phy;
> -	struct clk *hdmi_pclk;
> -	struct clk *venci_clk;
>  	struct regulator *hdmi_supply;
>  	u32 irq_stat;
>  	struct dw_hdmi *hdmi;
> @@ -946,6 +944,29 @@ static void meson_disable_regulator(void *data)
>  	regulator_disable(data);
>  }
>  
> +static void meson_disable_clk(void *data)
> +{
> +	clk_disable_unprepare(data);
> +}
> +
> +static int meson_enable_clk(struct device *dev, char *name)
> +{
> +	struct clk *clk;
> +	int ret;
> +
> +	clk = devm_clk_get(dev, name);
> +	if (IS_ERR(clk)) {
> +		dev_err(dev, "Unable to get %s pclk\n", name);
> +		return PTR_ERR(clk);
> +	}
> +
> +	ret = clk_prepare_enable(clk);
> +	if (!ret)
> +		ret = devm_add_action_or_reset(dev, meson_disable_clk, clk);
> +
> +	return ret;
> +}
> +
>  static int meson_dw_hdmi_bind(struct device *dev, struct device *master,
>  				void *data)
>  {
> @@ -1026,19 +1047,13 @@ static int meson_dw_hdmi_bind(struct device *dev, struct device *master,
>  	if (IS_ERR(meson_dw_hdmi->hdmitx))
>  		return PTR_ERR(meson_dw_hdmi->hdmitx);
>  
> -	meson_dw_hdmi->hdmi_pclk = devm_clk_get(dev, "isfr");
> -	if (IS_ERR(meson_dw_hdmi->hdmi_pclk)) {
> -		dev_err(dev, "Unable to get HDMI pclk\n");
> -		return PTR_ERR(meson_dw_hdmi->hdmi_pclk);
> -	}
> -	clk_prepare_enable(meson_dw_hdmi->hdmi_pclk);
> +	ret = meson_enable_clk(dev, "isfr");
> +	if (ret)
> +		return ret;
>  
> -	meson_dw_hdmi->venci_clk = devm_clk_get(dev, "venci");
> -	if (IS_ERR(meson_dw_hdmi->venci_clk)) {
> -		dev_err(dev, "Unable to get venci clk\n");
> -		return PTR_ERR(meson_dw_hdmi->venci_clk);
> -	}
> -	clk_prepare_enable(meson_dw_hdmi->venci_clk);
> +	ret = meson_enable_clk(dev, "venci");
> +	if (ret)
> +		return ret;
>  
>  	dw_plat_data->regm = devm_regmap_init(dev, NULL, meson_dw_hdmi,
>  					      &meson_dw_hdmi_regmap_config);
> 

Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Jerome Brunet Nov. 23, 2020, 2:03 p.m. UTC | #2
On Fri 20 Nov 2020 at 10:42, Marc Zyngier <maz@kernel.org> wrote:

> The HDMI driver request clocks early, but never disable them, leaving
> the clocks on even when the driver is removed.
>
> Fix it by slightly refactoring the clock code, and register a devm
> action that will eventually disable/unprepare the enabled clocks.
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> ---
>  drivers/gpu/drm/meson/meson_dw_hdmi.c | 43 ++++++++++++++++++---------
>  1 file changed, 29 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/gpu/drm/meson/meson_dw_hdmi.c b/drivers/gpu/drm/meson/meson_dw_hdmi.c
> index 7f8eea494147..29623b309cb1 100644
> --- a/drivers/gpu/drm/meson/meson_dw_hdmi.c
> +++ b/drivers/gpu/drm/meson/meson_dw_hdmi.c
> @@ -145,8 +145,6 @@ struct meson_dw_hdmi {
>  	struct reset_control *hdmitx_apb;
>  	struct reset_control *hdmitx_ctrl;
>  	struct reset_control *hdmitx_phy;
> -	struct clk *hdmi_pclk;
> -	struct clk *venci_clk;
>  	struct regulator *hdmi_supply;
>  	u32 irq_stat;
>  	struct dw_hdmi *hdmi;
> @@ -946,6 +944,29 @@ static void meson_disable_regulator(void *data)
>  	regulator_disable(data);
>  }
>  
> +static void meson_disable_clk(void *data)
> +{
> +	clk_disable_unprepare(data);
> +}
> +
> +static int meson_enable_clk(struct device *dev, char *name)
> +{
> +	struct clk *clk;
> +	int ret;
> +
> +	clk = devm_clk_get(dev, name);
> +	if (IS_ERR(clk)) {
> +		dev_err(dev, "Unable to get %s pclk\n", name);
> +		return PTR_ERR(clk);
> +	}
> +
> +	ret = clk_prepare_enable(clk);
> +	if (!ret)
> +		ret = devm_add_action_or_reset(dev, meson_disable_clk,
> clk);

Thanks for fixing this Marc.

FYI, while it is fine to declare a function to disable the clocks, a quick
cast may avoid it

devm_add_action_or_reset(dev, (void(*)(void *))clk_disable_unprepare, clk);

> +
> +	return ret;
> +}
> +
>  static int meson_dw_hdmi_bind(struct device *dev, struct device *master,
>  				void *data)
>  {
> @@ -1026,19 +1047,13 @@ static int meson_dw_hdmi_bind(struct device *dev, struct device *master,
>  	if (IS_ERR(meson_dw_hdmi->hdmitx))
>  		return PTR_ERR(meson_dw_hdmi->hdmitx);
>  
> -	meson_dw_hdmi->hdmi_pclk = devm_clk_get(dev, "isfr");
> -	if (IS_ERR(meson_dw_hdmi->hdmi_pclk)) {
> -		dev_err(dev, "Unable to get HDMI pclk\n");
> -		return PTR_ERR(meson_dw_hdmi->hdmi_pclk);
> -	}
> -	clk_prepare_enable(meson_dw_hdmi->hdmi_pclk);
> +	ret = meson_enable_clk(dev, "isfr");
> +	if (ret)
> +		return ret;
>  
> -	meson_dw_hdmi->venci_clk = devm_clk_get(dev, "venci");
> -	if (IS_ERR(meson_dw_hdmi->venci_clk)) {
> -		dev_err(dev, "Unable to get venci clk\n");
> -		return PTR_ERR(meson_dw_hdmi->venci_clk);
> -	}
> -	clk_prepare_enable(meson_dw_hdmi->venci_clk);
> +	ret = meson_enable_clk(dev, "venci");
> +	if (ret)
> +		return ret;
>  
>  	dw_plat_data->regm = devm_regmap_init(dev, NULL, meson_dw_hdmi,
>  					      &meson_dw_hdmi_regmap_config);
Marc Zyngier Nov. 23, 2020, 2:15 p.m. UTC | #3
On 2020-11-23 14:03, Jerome Brunet wrote:
> On Fri 20 Nov 2020 at 10:42, Marc Zyngier <maz@kernel.org> wrote:
> 
>> The HDMI driver request clocks early, but never disable them, leaving
>> the clocks on even when the driver is removed.
>> 
>> Fix it by slightly refactoring the clock code, and register a devm
>> action that will eventually disable/unprepare the enabled clocks.
>> 
>> Signed-off-by: Marc Zyngier <maz@kernel.org>
>> ---
>>  drivers/gpu/drm/meson/meson_dw_hdmi.c | 43 
>> ++++++++++++++++++---------
>>  1 file changed, 29 insertions(+), 14 deletions(-)
>> 
>> diff --git a/drivers/gpu/drm/meson/meson_dw_hdmi.c 
>> b/drivers/gpu/drm/meson/meson_dw_hdmi.c
>> index 7f8eea494147..29623b309cb1 100644
>> --- a/drivers/gpu/drm/meson/meson_dw_hdmi.c
>> +++ b/drivers/gpu/drm/meson/meson_dw_hdmi.c
>> @@ -145,8 +145,6 @@ struct meson_dw_hdmi {
>>  	struct reset_control *hdmitx_apb;
>>  	struct reset_control *hdmitx_ctrl;
>>  	struct reset_control *hdmitx_phy;
>> -	struct clk *hdmi_pclk;
>> -	struct clk *venci_clk;
>>  	struct regulator *hdmi_supply;
>>  	u32 irq_stat;
>>  	struct dw_hdmi *hdmi;
>> @@ -946,6 +944,29 @@ static void meson_disable_regulator(void *data)
>>  	regulator_disable(data);
>>  }
>> 
>> +static void meson_disable_clk(void *data)
>> +{
>> +	clk_disable_unprepare(data);
>> +}
>> +
>> +static int meson_enable_clk(struct device *dev, char *name)
>> +{
>> +	struct clk *clk;
>> +	int ret;
>> +
>> +	clk = devm_clk_get(dev, name);
>> +	if (IS_ERR(clk)) {
>> +		dev_err(dev, "Unable to get %s pclk\n", name);
>> +		return PTR_ERR(clk);
>> +	}
>> +
>> +	ret = clk_prepare_enable(clk);
>> +	if (!ret)
>> +		ret = devm_add_action_or_reset(dev, meson_disable_clk,
>> clk);
> 
> Thanks for fixing this Marc.
> 
> FYI, while it is fine to declare a function to disable the clocks, a 
> quick
> cast may avoid it
> 
> devm_add_action_or_reset(dev, (void(*)(void *))clk_disable_unprepare, 
> clk);

While this works for now, a change to the clk_disable_unprepare()
prototype (such as adding a second argument) would now go completely
unnoticed (after all, you've cast the function, it *must* be correct,
right?), and someone would spend a few hours trying to track down memory
corruption or some other interesting results.

Yes, casting C functions can be hilarious.

I can see a few uses of this hack in the tree, and I have my pop-corn
ready.

Thanks,

         M.
diff mbox series

Patch

diff --git a/drivers/gpu/drm/meson/meson_dw_hdmi.c b/drivers/gpu/drm/meson/meson_dw_hdmi.c
index 7f8eea494147..29623b309cb1 100644
--- a/drivers/gpu/drm/meson/meson_dw_hdmi.c
+++ b/drivers/gpu/drm/meson/meson_dw_hdmi.c
@@ -145,8 +145,6 @@  struct meson_dw_hdmi {
 	struct reset_control *hdmitx_apb;
 	struct reset_control *hdmitx_ctrl;
 	struct reset_control *hdmitx_phy;
-	struct clk *hdmi_pclk;
-	struct clk *venci_clk;
 	struct regulator *hdmi_supply;
 	u32 irq_stat;
 	struct dw_hdmi *hdmi;
@@ -946,6 +944,29 @@  static void meson_disable_regulator(void *data)
 	regulator_disable(data);
 }
 
+static void meson_disable_clk(void *data)
+{
+	clk_disable_unprepare(data);
+}
+
+static int meson_enable_clk(struct device *dev, char *name)
+{
+	struct clk *clk;
+	int ret;
+
+	clk = devm_clk_get(dev, name);
+	if (IS_ERR(clk)) {
+		dev_err(dev, "Unable to get %s pclk\n", name);
+		return PTR_ERR(clk);
+	}
+
+	ret = clk_prepare_enable(clk);
+	if (!ret)
+		ret = devm_add_action_or_reset(dev, meson_disable_clk, clk);
+
+	return ret;
+}
+
 static int meson_dw_hdmi_bind(struct device *dev, struct device *master,
 				void *data)
 {
@@ -1026,19 +1047,13 @@  static int meson_dw_hdmi_bind(struct device *dev, struct device *master,
 	if (IS_ERR(meson_dw_hdmi->hdmitx))
 		return PTR_ERR(meson_dw_hdmi->hdmitx);
 
-	meson_dw_hdmi->hdmi_pclk = devm_clk_get(dev, "isfr");
-	if (IS_ERR(meson_dw_hdmi->hdmi_pclk)) {
-		dev_err(dev, "Unable to get HDMI pclk\n");
-		return PTR_ERR(meson_dw_hdmi->hdmi_pclk);
-	}
-	clk_prepare_enable(meson_dw_hdmi->hdmi_pclk);
+	ret = meson_enable_clk(dev, "isfr");
+	if (ret)
+		return ret;
 
-	meson_dw_hdmi->venci_clk = devm_clk_get(dev, "venci");
-	if (IS_ERR(meson_dw_hdmi->venci_clk)) {
-		dev_err(dev, "Unable to get venci clk\n");
-		return PTR_ERR(meson_dw_hdmi->venci_clk);
-	}
-	clk_prepare_enable(meson_dw_hdmi->venci_clk);
+	ret = meson_enable_clk(dev, "venci");
+	if (ret)
+		return ret;
 
 	dw_plat_data->regm = devm_regmap_init(dev, NULL, meson_dw_hdmi,
 					      &meson_dw_hdmi_regmap_config);