diff mbox series

[2/2] drm/imagination: add reset control support

Message ID 20241125-pvr-reset-v1-2-b437b8052948@linumiz.com (mailing list archive)
State New
Headers show
Series drm/imagination: add reset handling | expand

Commit Message

Parthiban Nov. 25, 2024, 4:37 p.m. UTC 
On some platforms like Allwinner A133 with GE8300 includes
reset control from reset control unit. Add reset control
optionally from the devicetree.

Signed-off-by: Parthiban Nallathambi <parthiban@linumiz.com>
---
 drivers/gpu/drm/imagination/pvr_device.h |  8 ++++++++
 drivers/gpu/drm/imagination/pvr_drv.c    |  5 +++++
 drivers/gpu/drm/imagination/pvr_power.c  | 16 +++++++++++++++-
 3 files changed, 28 insertions(+), 1 deletion(-)

Comments

Philipp Zabel Nov. 26, 2024, 9:29 a.m. UTC | #1 
On Mo, 2024-11-25 at 22:07 +0530, Parthiban Nallathambi wrote:
> On some platforms like Allwinner A133 with GE8300 includes
> reset control from reset control unit. Add reset control
> optionally from the devicetree.
> 
> Signed-off-by: Parthiban Nallathambi <parthiban@linumiz.com>
> ---
>  drivers/gpu/drm/imagination/pvr_device.h |  8 ++++++++
>  drivers/gpu/drm/imagination/pvr_drv.c    |  5 +++++
>  drivers/gpu/drm/imagination/pvr_power.c  | 16 +++++++++++++++-
>  3 files changed, 28 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/imagination/pvr_device.h b/drivers/gpu/drm/imagination/pvr_device.h
> index 6d0dfacb677b..21ec7dd64415 100644
> --- a/drivers/gpu/drm/imagination/pvr_device.h
> +++ b/drivers/gpu/drm/imagination/pvr_device.h
> @@ -23,6 +23,7 @@
>  #include <linux/kernel.h>
>  #include <linux/math.h>
>  #include <linux/mutex.h>
> +#include <linux/reset.h>
>  #include <linux/spinlock_types.h>
>  #include <linux/timer.h>
>  #include <linux/types.h>
> @@ -131,6 +132,13 @@ struct pvr_device {
>  	 */
>  	struct clk *mem_clk;
>  
> +	/**
> +	 * @reset: Optional reset control
> +	 *
> +	 * This may be used on some platforms to reset the GPU module/IP.
> +	 */
> +	struct reset_control *reset;
> +
>  	/** @irq: IRQ number. */
>  	int irq;
>  
> diff --git a/drivers/gpu/drm/imagination/pvr_drv.c b/drivers/gpu/drm/imagination/pvr_drv.c
> index fb17196e05f4..d9b918410ea9 100644
> --- a/drivers/gpu/drm/imagination/pvr_drv.c
> +++ b/drivers/gpu/drm/imagination/pvr_drv.c
> @@ -36,6 +36,7 @@
>  #include <linux/of_platform.h>
>  #include <linux/platform_device.h>
>  #include <linux/pm_runtime.h>
> +#include <linux/reset.h>
>  #include <linux/xarray.h>
>  
>  /**
> @@ -1427,6 +1428,10 @@ pvr_probe(struct platform_device *plat_dev)
>  	pm_runtime_use_autosuspend(&plat_dev->dev);
>  	pvr_watchdog_init(pvr_dev);
>  
> +	pvr_dev->reset = devm_reset_control_get_optional_exclusive(&plat_dev->dev, "ahb");
> +	if (PTR_ERR(pvr_dev->reset) == -EPROBE_DEFER)
> +		return PTR_ERR(pvr_dev->reset);

	pvr_dev->reset = devm_reset_control_get_optional_exclusive(&plat_dev->dev, "ahb");
	if (IS_ERR(pvr_dev->reset))
		return PTR_ERR(pvr_dev->reset);

Please don't ignore errors. devm_reset_control_get_optional_exclusive()
returns NULL if the "ahb" reset control isn't specified in the device
tree, and the reset_control_assert/deassert() functions accept that as
a non-existing reset, see [1].

[1] https://docs.kernel.org/driver-api/reset.html#optional-resets

> +
>  	err = pvr_device_init(pvr_dev);
>  	if (err)
>  		goto err_watchdog_fini;
> diff --git a/drivers/gpu/drm/imagination/pvr_power.c b/drivers/gpu/drm/imagination/pvr_power.c
> index ba7816fd28ec..a24ed85f36c7 100644
> --- a/drivers/gpu/drm/imagination/pvr_power.c
> +++ b/drivers/gpu/drm/imagination/pvr_power.c
> @@ -15,6 +15,7 @@
>  #include <linux/mutex.h>
>  #include <linux/platform_device.h>
>  #include <linux/pm_runtime.h>
> +#include <linux/reset.h>
>  #include <linux/timer.h>
>  #include <linux/types.h>
>  #include <linux/workqueue.h>
> @@ -252,6 +253,9 @@ pvr_power_device_suspend(struct device *dev)
>  	clk_disable_unprepare(pvr_dev->sys_clk);
>  	clk_disable_unprepare(pvr_dev->core_clk);
>  
> +	if (!IS_ERR(pvr_dev->reset))
> +		reset_control_assert(pvr_dev->reset);

	reset_control_assert(pvr_dev->reset);

This just returns 0 if pvr_dev->reset == NULL.

> +
>  err_drm_dev_exit:
>  	drm_dev_exit(idx);
>  
> @@ -270,9 +274,15 @@ pvr_power_device_resume(struct device *dev)
>  	if (!drm_dev_enter(drm_dev, &idx))
>  		return -EIO;
>  
> +	if (!IS_ERR(pvr_dev->reset)) {
> +		err = reset_control_reset(pvr_dev->reset);
> +		if (err)
> +			goto err_drm_dev_exit;
> +	}

	err = reset_control_reset(pvr_dev->reset);
	if (err)
		goto err_drm_dev_exit;

> +
>  	err = clk_prepare_enable(pvr_dev->core_clk);
>  	if (err)
> -		goto err_drm_dev_exit;
> +		goto err_reset_exit;
>  
>  	err = clk_prepare_enable(pvr_dev->sys_clk);
>  	if (err)
> @@ -301,6 +311,10 @@ pvr_power_device_resume(struct device *dev)
>  err_core_clk_disable:
>  	clk_disable_unprepare(pvr_dev->core_clk);
>  
> +err_reset_exit:
> +	if (!IS_ERR(pvr_dev->reset))
> +		reset_control_assert(pvr_dev->reset);

err_reset_exit:
	reset_control_assert(pvr_dev->reset);

> +
>  err_drm_dev_exit:
>  	drm_dev_exit(idx);
>  
> 

regards
Philipp
Parthiban Nov. 26, 2024, 9:48 a.m. UTC | #2 
On 11/26/24 2:59 PM, Philipp Zabel wrote:
> On Mo, 2024-11-25 at 22:07 +0530, Parthiban Nallathambi wrote:
>> On some platforms like Allwinner A133 with GE8300 includes
>> reset control from reset control unit. Add reset control
>> optionally from the devicetree.
>>
>> Signed-off-by: Parthiban Nallathambi <parthiban@linumiz.com>
>> ---
>>  drivers/gpu/drm/imagination/pvr_device.h |  8 ++++++++
>>  drivers/gpu/drm/imagination/pvr_drv.c    |  5 +++++
>>  drivers/gpu/drm/imagination/pvr_power.c  | 16 +++++++++++++++-
>>  3 files changed, 28 insertions(+), 1 deletion(-)
Thanks for the reviews. As with the binding patch comments, reset control
needs to be added together with the consumer i.e in this case GE8300 GPU
in Allwinner A133 SoC.

I will address the comments when sending patch with support for GE8300.

Thanks,
Parthiban
diff mbox series

Patch

diff --git a/drivers/gpu/drm/imagination/pvr_device.h b/drivers/gpu/drm/imagination/pvr_device.h
index 6d0dfacb677b..21ec7dd64415 100644
--- a/drivers/gpu/drm/imagination/pvr_device.h
+++ b/drivers/gpu/drm/imagination/pvr_device.h
@@ -23,6 +23,7 @@ 
 #include <linux/kernel.h>
 #include <linux/math.h>
 #include <linux/mutex.h>
+#include <linux/reset.h>
 #include <linux/spinlock_types.h>
 #include <linux/timer.h>
 #include <linux/types.h>
@@ -131,6 +132,13 @@  struct pvr_device {
 	 */
 	struct clk *mem_clk;
 
+	/**
+	 * @reset: Optional reset control
+	 *
+	 * This may be used on some platforms to reset the GPU module/IP.
+	 */
+	struct reset_control *reset;
+
 	/** @irq: IRQ number. */
 	int irq;
 
diff --git a/drivers/gpu/drm/imagination/pvr_drv.c b/drivers/gpu/drm/imagination/pvr_drv.c
index fb17196e05f4..d9b918410ea9 100644
--- a/drivers/gpu/drm/imagination/pvr_drv.c
+++ b/drivers/gpu/drm/imagination/pvr_drv.c
@@ -36,6 +36,7 @@ 
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
+#include <linux/reset.h>
 #include <linux/xarray.h>
 
 /**
@@ -1427,6 +1428,10 @@  pvr_probe(struct platform_device *plat_dev)
 	pm_runtime_use_autosuspend(&plat_dev->dev);
 	pvr_watchdog_init(pvr_dev);
 
+	pvr_dev->reset = devm_reset_control_get_optional_exclusive(&plat_dev->dev, "ahb");
+	if (PTR_ERR(pvr_dev->reset) == -EPROBE_DEFER)
+		return PTR_ERR(pvr_dev->reset);
+
 	err = pvr_device_init(pvr_dev);
 	if (err)
 		goto err_watchdog_fini;
diff --git a/drivers/gpu/drm/imagination/pvr_power.c b/drivers/gpu/drm/imagination/pvr_power.c
index ba7816fd28ec..a24ed85f36c7 100644
--- a/drivers/gpu/drm/imagination/pvr_power.c
+++ b/drivers/gpu/drm/imagination/pvr_power.c
@@ -15,6 +15,7 @@ 
 #include <linux/mutex.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
+#include <linux/reset.h>
 #include <linux/timer.h>
 #include <linux/types.h>
 #include <linux/workqueue.h>
@@ -252,6 +253,9 @@  pvr_power_device_suspend(struct device *dev)
 	clk_disable_unprepare(pvr_dev->sys_clk);
 	clk_disable_unprepare(pvr_dev->core_clk);
 
+	if (!IS_ERR(pvr_dev->reset))
+		reset_control_assert(pvr_dev->reset);
+
 err_drm_dev_exit:
 	drm_dev_exit(idx);
 
@@ -270,9 +274,15 @@  pvr_power_device_resume(struct device *dev)
 	if (!drm_dev_enter(drm_dev, &idx))
 		return -EIO;
 
+	if (!IS_ERR(pvr_dev->reset)) {
+		err = reset_control_reset(pvr_dev->reset);
+		if (err)
+			goto err_drm_dev_exit;
+	}
+
 	err = clk_prepare_enable(pvr_dev->core_clk);
 	if (err)
-		goto err_drm_dev_exit;
+		goto err_reset_exit;
 
 	err = clk_prepare_enable(pvr_dev->sys_clk);
 	if (err)
@@ -301,6 +311,10 @@  pvr_power_device_resume(struct device *dev)
 err_core_clk_disable:
 	clk_disable_unprepare(pvr_dev->core_clk);
 
+err_reset_exit:
+	if (!IS_ERR(pvr_dev->reset))
+		reset_control_assert(pvr_dev->reset);
+
 err_drm_dev_exit:
 	drm_dev_exit(idx);