Re: [PATCH v13 1/4] drm/imagination: Use pwrseq for TH1520 GPU power management

[Michal Wilczynski <m.wilczynski@samsung.com>]

On 8/22/25 12:26, Michal Wilczynski wrote:
> 
> 
> On 8/22/25 12:04, Michal Wilczynski wrote:
>>
>>
>> On 8/22/25 11:28, Matt Coster wrote:
>>> On 21/08/2025 23:20, Michal Wilczynski wrote:
>>>> Update the Imagination PVR DRM driver to leverage the pwrseq framework
>>>> for managing the complex power sequence of the GPU on the T-HEAD TH1520
>>>> SoC.
>>>>
>>>> To cleanly separate platform-specific logic from the generic driver,
>>>> this patch introduces an `init` callback to the `pwr_power_sequence_ops`
>>>> struct. This allows for different power management strategies to be
>>>> selected at probe time based on the device's compatible string.
>>>>
>>>> A `pvr_device_data` struct, associated with each compatible in the
>>>> of_device_id table, points to the appropriate ops table (manual or
>>>> pwrseq).
>>>>
>>>> At probe time, the driver now calls the `->init()` op. For pwrseq-based
>>>> platforms, this callback calls `devm_pwrseq_get("gpu-power")`, deferring
>>>> probe if the sequencer is not yet available. For other platforms, it
>>>> falls back to the existing manual clock and reset handling. The runtime
>>>> PM callbacks continue to call the appropriate functions via the ops
>>>> table.
>>>>
>>>> Signed-off-by: Michal Wilczynski <m.wilczynski@samsung.com>
>>>
>>> Reviewed-by: Matt Coster <matt.coster@imgtec.com>
>>>
>>> Would you like me to take the non-DTS changes via drm-misc-next?
>>
>> Yeah I think this would be appropriate.
>> Thanks !
> 
> Hi Drew,
> 
> Matt offered to take the non-DTS patches (1/4 and 4/4) from this series
> through the DRM tree.
> 
> This leaves the DT binding and TH1520 DT patches (2/4 and 3/4). Would
> you be able to pick them up through your tree ?

Aw,
Sorry I think Matt also meant to take the dt-binding patch, so there would be
only patch 3 for your tree.

Thanks !

> 
> Thanks !
> 
>>
>>>
>>> Cheers,
>>> Matt
>>>
>>>> ---
>>>>  drivers/gpu/drm/imagination/pvr_device.c |  22 +----
>>>>  drivers/gpu/drm/imagination/pvr_device.h |  17 ++++
>>>>  drivers/gpu/drm/imagination/pvr_drv.c    |  23 ++++-
>>>>  drivers/gpu/drm/imagination/pvr_power.c  | 158 +++++++++++++++++++++++--------
>>>>  drivers/gpu/drm/imagination/pvr_power.h  |  15 +++
>>>>  5 files changed, 176 insertions(+), 59 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/imagination/pvr_device.c b/drivers/gpu/drm/imagination/pvr_device.c
>>>> index 8b9ba4983c4cb5bc40342fcafc4259078bc70547..294b6019b4155bb7fdb7de73ccf7fa8ad867811f 100644
>>>> --- a/drivers/gpu/drm/imagination/pvr_device.c
>>>> +++ b/drivers/gpu/drm/imagination/pvr_device.c
>>>> @@ -23,6 +23,7 @@
>>>>  #include <linux/firmware.h>
>>>>  #include <linux/gfp.h>
>>>>  #include <linux/interrupt.h>
>>>> +#include <linux/of.h>
>>>>  #include <linux/platform_device.h>
>>>>  #include <linux/pm_runtime.h>
>>>>  #include <linux/reset.h>
>>>> @@ -121,21 +122,6 @@ static int pvr_device_clk_init(struct pvr_device *pvr_dev)
>>>>  	return 0;
>>>>  }
>>>>  
>>>> -static int pvr_device_reset_init(struct pvr_device *pvr_dev)
>>>> -{
>>>> -	struct drm_device *drm_dev = from_pvr_device(pvr_dev);
>>>> -	struct reset_control *reset;
>>>> -
>>>> -	reset = devm_reset_control_get_optional_exclusive(drm_dev->dev, NULL);
>>>> -	if (IS_ERR(reset))
>>>> -		return dev_err_probe(drm_dev->dev, PTR_ERR(reset),
>>>> -				     "failed to get gpu reset line\n");
>>>> -
>>>> -	pvr_dev->reset = reset;
>>>> -
>>>> -	return 0;
>>>> -}
>>>> -
>>>>  /**
>>>>   * pvr_device_process_active_queues() - Process all queue related events.
>>>>   * @pvr_dev: PowerVR device to check
>>>> @@ -618,6 +604,9 @@ pvr_device_init(struct pvr_device *pvr_dev)
>>>>  	struct device *dev = drm_dev->dev;
>>>>  	int err;
>>>>  
>>>> +	/* Get the platform-specific data based on the compatible string. */
>>>> +	pvr_dev->device_data = of_device_get_match_data(dev);
>>>> +
>>>>  	/*
>>>>  	 * Setup device parameters. We do this first in case other steps
>>>>  	 * depend on them.
>>>> @@ -631,8 +620,7 @@ pvr_device_init(struct pvr_device *pvr_dev)
>>>>  	if (err)
>>>>  		return err;
>>>>  
>>>> -	/* Get the reset line for the GPU */
>>>> -	err = pvr_device_reset_init(pvr_dev);
>>>> +	err = pvr_dev->device_data->pwr_ops->init(pvr_dev);
>>>>  	if (err)
>>>>  		return err;
>>>>  
>>>> diff --git a/drivers/gpu/drm/imagination/pvr_device.h b/drivers/gpu/drm/imagination/pvr_device.h
>>>> index 7cb01c38d2a9c3fc71effe789d4dfe54eddd93ee..ab8f56ae15df6c2888feb16b1d87b59510961936 100644
>>>> --- a/drivers/gpu/drm/imagination/pvr_device.h
>>>> +++ b/drivers/gpu/drm/imagination/pvr_device.h
>>>> @@ -37,6 +37,9 @@ struct clk;
>>>>  /* Forward declaration from <linux/firmware.h>. */
>>>>  struct firmware;
>>>>  
>>>> +/* Forward declaration from <linux/pwrseq/consumer.h> */
>>>> +struct pwrseq_desc;
>>>> +
>>>>  /**
>>>>   * struct pvr_gpu_id - Hardware GPU ID information for a PowerVR device
>>>>   * @b: Branch ID.
>>>> @@ -57,6 +60,14 @@ struct pvr_fw_version {
>>>>  	u16 major, minor;
>>>>  };
>>>>  
>>>> +/**
>>>> + * struct pvr_device_data - Platform specific data associated with a compatible string.
>>>> + * @pwr_ops: Pointer to a structure with platform-specific power functions.
>>>> + */
>>>> +struct pvr_device_data {
>>>> +	const struct pvr_power_sequence_ops *pwr_ops;
>>>> +};
>>>> +
>>>>  /**
>>>>   * struct pvr_device - powervr-specific wrapper for &struct drm_device
>>>>   */
>>>> @@ -98,6 +109,9 @@ struct pvr_device {
>>>>  	/** @fw_version: Firmware version detected at runtime. */
>>>>  	struct pvr_fw_version fw_version;
>>>>  
>>>> +	/** @device_data: Pointer to platform-specific data. */
>>>> +	const struct pvr_device_data *device_data;
>>>> +
>>>>  	/** @regs_resource: Resource representing device control registers. */
>>>>  	struct resource *regs_resource;
>>>>  
>>>> @@ -148,6 +162,9 @@ struct pvr_device {
>>>>  	 */
>>>>  	struct reset_control *reset;
>>>>  
>>>> +	/** @pwrseq: Pointer to a power sequencer, if one is used. */
>>>> +	struct pwrseq_desc *pwrseq;
>>>> +
>>>>  	/** @irq: IRQ number. */
>>>>  	int irq;
>>>>  
>>>> diff --git a/drivers/gpu/drm/imagination/pvr_drv.c b/drivers/gpu/drm/imagination/pvr_drv.c
>>>> index b058ec183bb30ab5c3db17ebaadf2754520a2a1f..916b40ced7eb0408fe985ba1b83b3be2eb024bae 100644
>>>> --- a/drivers/gpu/drm/imagination/pvr_drv.c
>>>> +++ b/drivers/gpu/drm/imagination/pvr_drv.c
>>>> @@ -1480,15 +1480,33 @@ static void pvr_remove(struct platform_device *plat_dev)
>>>>  	pvr_power_domains_fini(pvr_dev);
>>>>  }
>>>>  
>>>> +static const struct pvr_device_data pvr_device_data_manual = {
>>>> +	.pwr_ops = &pvr_power_sequence_ops_manual,
>>>> +};
>>>> +
>>>> +static const struct pvr_device_data pvr_device_data_pwrseq = {
>>>> +	.pwr_ops = &pvr_power_sequence_ops_pwrseq,
>>>> +};
>>>> +
>>>>  static const struct of_device_id dt_match[] = {
>>>> -	{ .compatible = "img,img-rogue", .data = NULL },
>>>> +	{
>>>> +		.compatible = "thead,th1520-gpu",
>>>> +		.data = &pvr_device_data_pwrseq,
>>>> +	},
>>>> +	{
>>>> +		.compatible = "img,img-rogue",
>>>> +		.data = &pvr_device_data_manual,
>>>> +	},
>>>>  
>>>>  	/*
>>>>  	 * This legacy compatible string was introduced early on before the more generic
>>>>  	 * "img,img-rogue" was added. Keep it around here for compatibility, but never use
>>>>  	 * "img,img-axe" in new devicetrees.
>>>>  	 */
>>>> -	{ .compatible = "img,img-axe", .data = NULL },
>>>> +	{
>>>> +		.compatible = "img,img-axe",
>>>> +		.data = &pvr_device_data_manual,
>>>> +	},
>>>>  	{}
>>>>  };
>>>>  MODULE_DEVICE_TABLE(of, dt_match);
>>>> @@ -1513,4 +1531,5 @@ MODULE_DESCRIPTION(PVR_DRIVER_DESC);
>>>>  MODULE_LICENSE("Dual MIT/GPL");
>>>>  MODULE_IMPORT_NS("DMA_BUF");
>>>>  MODULE_FIRMWARE("powervr/rogue_33.15.11.3_v1.fw");
>>>> +MODULE_FIRMWARE("powervr/rogue_36.52.104.182_v1.fw");
>>>>  MODULE_FIRMWARE("powervr/rogue_36.53.104.796_v1.fw");
>>>> diff --git a/drivers/gpu/drm/imagination/pvr_power.c b/drivers/gpu/drm/imagination/pvr_power.c
>>>> index 187a07e0bd9adb2f0713ac2c8e091229f4027354..c6e7ff9e935d3b348eff6953c633c72410fdf507 100644
>>>> --- a/drivers/gpu/drm/imagination/pvr_power.c
>>>> +++ b/drivers/gpu/drm/imagination/pvr_power.c
>>>> @@ -18,6 +18,7 @@
>>>>  #include <linux/platform_device.h>
>>>>  #include <linux/pm_domain.h>
>>>>  #include <linux/pm_runtime.h>
>>>> +#include <linux/pwrseq/consumer.h>
>>>>  #include <linux/reset.h>
>>>>  #include <linux/timer.h>
>>>>  #include <linux/types.h>
>>>> @@ -234,6 +235,118 @@ pvr_watchdog_init(struct pvr_device *pvr_dev)
>>>>  	return 0;
>>>>  }
>>>>  
>>>> +static int pvr_power_init_manual(struct pvr_device *pvr_dev)
>>>> +{
>>>> +	struct drm_device *drm_dev = from_pvr_device(pvr_dev);
>>>> +	struct reset_control *reset;
>>>> +
>>>> +	reset = devm_reset_control_get_optional_exclusive(drm_dev->dev, NULL);
>>>> +	if (IS_ERR(reset))
>>>> +		return dev_err_probe(drm_dev->dev, PTR_ERR(reset),
>>>> +				     "failed to get gpu reset line\n");
>>>> +
>>>> +	pvr_dev->reset = reset;
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +static int pvr_power_on_sequence_manual(struct pvr_device *pvr_dev)
>>>> +{
>>>> +	int err;
>>>> +
>>>> +	err = clk_prepare_enable(pvr_dev->core_clk);
>>>> +	if (err)
>>>> +		return err;
>>>> +
>>>> +	err = clk_prepare_enable(pvr_dev->sys_clk);
>>>> +	if (err)
>>>> +		goto err_core_clk_disable;
>>>> +
>>>> +	err = clk_prepare_enable(pvr_dev->mem_clk);
>>>> +	if (err)
>>>> +		goto err_sys_clk_disable;
>>>> +
>>>> +	/*
>>>> +	 * According to the hardware manual, a delay of at least 32 clock
>>>> +	 * cycles is required between de-asserting the clkgen reset and
>>>> +	 * de-asserting the GPU reset. Assuming a worst-case scenario with
>>>> +	 * a very high GPU clock frequency, a delay of 1 microsecond is
>>>> +	 * sufficient to ensure this requirement is met across all
>>>> +	 * feasible GPU clock speeds.
>>>> +	 */
>>>> +	udelay(1);
>>>> +
>>>> +	err = reset_control_deassert(pvr_dev->reset);
>>>> +	if (err)
>>>> +		goto err_mem_clk_disable;
>>>> +
>>>> +	return 0;
>>>> +
>>>> +err_mem_clk_disable:
>>>> +	clk_disable_unprepare(pvr_dev->mem_clk);
>>>> +
>>>> +err_sys_clk_disable:
>>>> +	clk_disable_unprepare(pvr_dev->sys_clk);
>>>> +
>>>> +err_core_clk_disable:
>>>> +	clk_disable_unprepare(pvr_dev->core_clk);
>>>> +
>>>> +	return err;
>>>> +}
>>>> +
>>>> +static int pvr_power_off_sequence_manual(struct pvr_device *pvr_dev)
>>>> +{
>>>> +	int err;
>>>> +
>>>> +	err = reset_control_assert(pvr_dev->reset);
>>>> +
>>>> +	clk_disable_unprepare(pvr_dev->mem_clk);
>>>> +	clk_disable_unprepare(pvr_dev->sys_clk);
>>>> +	clk_disable_unprepare(pvr_dev->core_clk);
>>>> +
>>>> +	return err;
>>>> +}
>>>> +
>>>> +const struct pvr_power_sequence_ops pvr_power_sequence_ops_manual = {
>>>> +	.init = pvr_power_init_manual,
>>>> +	.power_on = pvr_power_on_sequence_manual,
>>>> +	.power_off = pvr_power_off_sequence_manual,
>>>> +};
>>>> +
>>>> +static int pvr_power_init_pwrseq(struct pvr_device *pvr_dev)
>>>> +{
>>>> +	struct device *dev = from_pvr_device(pvr_dev)->dev;
>>>> +
>>>> +	pvr_dev->pwrseq = devm_pwrseq_get(dev, "gpu-power");
>>>> +	if (IS_ERR(pvr_dev->pwrseq)) {
>>>> +		/*
>>>> +		 * This platform requires a sequencer. If we can't get it, we
>>>> +		 * must return the error (including -EPROBE_DEFER to wait for
>>>> +		 * the provider to appear)
>>>> +		 */
>>>> +		return dev_err_probe(dev, PTR_ERR(pvr_dev->pwrseq),
>>>> +				     "Failed to get required power sequencer\n");
>>>> +	}
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +static int pvr_power_on_sequence_pwrseq(struct pvr_device *pvr_dev)
>>>> +{
>>>> +	return pwrseq_power_on(pvr_dev->pwrseq);
>>>> +}
>>>> +
>>>> +static int pvr_power_off_sequence_pwrseq(struct pvr_device *pvr_dev)
>>>> +{
>>>> +	return pwrseq_power_off(pvr_dev->pwrseq);
>>>> +}
>>>> +
>>>> +const struct pvr_power_sequence_ops pvr_power_sequence_ops_pwrseq = {
>>>> +	.init = pvr_power_init_pwrseq,
>>>> +	.power_on = pvr_power_on_sequence_pwrseq,
>>>> +	.power_off = pvr_power_off_sequence_pwrseq,
>>>> +};
>>>> +
>>>>  int
>>>>  pvr_power_device_suspend(struct device *dev)
>>>>  {
>>>> @@ -252,11 +365,7 @@ pvr_power_device_suspend(struct device *dev)
>>>>  			goto err_drm_dev_exit;
>>>>  	}
>>>>  
>>>> -	clk_disable_unprepare(pvr_dev->mem_clk);
>>>> -	clk_disable_unprepare(pvr_dev->sys_clk);
>>>> -	clk_disable_unprepare(pvr_dev->core_clk);
>>>> -
>>>> -	err = reset_control_assert(pvr_dev->reset);
>>>> +	err = pvr_dev->device_data->pwr_ops->power_off(pvr_dev);
>>>>  
>>>>  err_drm_dev_exit:
>>>>  	drm_dev_exit(idx);
>>>> @@ -276,53 +385,22 @@ pvr_power_device_resume(struct device *dev)
>>>>  	if (!drm_dev_enter(drm_dev, &idx))
>>>>  		return -EIO;
>>>>  
>>>> -	err = clk_prepare_enable(pvr_dev->core_clk);
>>>> +	err = pvr_dev->device_data->pwr_ops->power_on(pvr_dev);
>>>>  	if (err)
>>>>  		goto err_drm_dev_exit;
>>>>  
>>>> -	err = clk_prepare_enable(pvr_dev->sys_clk);
>>>> -	if (err)
>>>> -		goto err_core_clk_disable;
>>>> -
>>>> -	err = clk_prepare_enable(pvr_dev->mem_clk);
>>>> -	if (err)
>>>> -		goto err_sys_clk_disable;
>>>> -
>>>> -	/*
>>>> -	 * According to the hardware manual, a delay of at least 32 clock
>>>> -	 * cycles is required between de-asserting the clkgen reset and
>>>> -	 * de-asserting the GPU reset. Assuming a worst-case scenario with
>>>> -	 * a very high GPU clock frequency, a delay of 1 microsecond is
>>>> -	 * sufficient to ensure this requirement is met across all
>>>> -	 * feasible GPU clock speeds.
>>>> -	 */
>>>> -	udelay(1);
>>>> -
>>>> -	err = reset_control_deassert(pvr_dev->reset);
>>>> -	if (err)
>>>> -		goto err_mem_clk_disable;
>>>> -
>>>>  	if (pvr_dev->fw_dev.booted) {
>>>>  		err = pvr_power_fw_enable(pvr_dev);
>>>>  		if (err)
>>>> -			goto err_reset_assert;
>>>> +			goto err_power_off;
>>>>  	}
>>>>  
>>>>  	drm_dev_exit(idx);
>>>>  
>>>>  	return 0;
>>>>  
>>>> -err_reset_assert:
>>>> -	reset_control_assert(pvr_dev->reset);
>>>> -
>>>> -err_mem_clk_disable:
>>>> -	clk_disable_unprepare(pvr_dev->mem_clk);
>>>> -
>>>> -err_sys_clk_disable:
>>>> -	clk_disable_unprepare(pvr_dev->sys_clk);
>>>> -
>>>> -err_core_clk_disable:
>>>> -	clk_disable_unprepare(pvr_dev->core_clk);
>>>> +err_power_off:
>>>> +	pvr_dev->device_data->pwr_ops->power_off(pvr_dev);
>>>>  
>>>>  err_drm_dev_exit:
>>>>  	drm_dev_exit(idx);
>>>> diff --git a/drivers/gpu/drm/imagination/pvr_power.h b/drivers/gpu/drm/imagination/pvr_power.h
>>>> index ada85674a7ca762dcf92df40424230e1c3910342..b853d092242cc90cb98cf66100679a309055a1dc 100644
>>>> --- a/drivers/gpu/drm/imagination/pvr_power.h
>>>> +++ b/drivers/gpu/drm/imagination/pvr_power.h
>>>> @@ -41,4 +41,19 @@ pvr_power_put(struct pvr_device *pvr_dev)
>>>>  int pvr_power_domains_init(struct pvr_device *pvr_dev);
>>>>  void pvr_power_domains_fini(struct pvr_device *pvr_dev);
>>>>  
>>>> +/**
>>>> + * struct pvr_power_sequence_ops - Platform specific power sequence operations.
>>>> + * @init: Pointer to the platform-specific initialization function.
>>>> + * @power_on: Pointer to the platform-specific power on function.
>>>> + * @power_off: Pointer to the platform-specific power off function.
>>>> + */
>>>> +struct pvr_power_sequence_ops {
>>>> +	int (*init)(struct pvr_device *pvr_dev);
>>>> +	int (*power_on)(struct pvr_device *pvr_dev);
>>>> +	int (*power_off)(struct pvr_device *pvr_dev);
>>>> +};
>>>> +
>>>> +extern const struct pvr_power_sequence_ops pvr_power_sequence_ops_manual;
>>>> +extern const struct pvr_power_sequence_ops pvr_power_sequence_ops_pwrseq;
>>>> +
>>>>  #endif /* PVR_POWER_H */
>>>>
>>>
>>>
>>
>> Best regards,
> 
> Best regards,

Best regards,
-- 
Michal Wilczynski <m.wilczynski@samsung.com>