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

[Matt Coster <Matt.Coster@imgtec.com>]

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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?

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 */
> 


-- 
Matt Coster
E: matt.coster@imgtec.com

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