Message-ID: <daf94e44-7c37-4fa6-a31e-b043b7bf46f1@samsung.com>
Date: Fri, 22 Aug 2025 12:26:08 +0200
From: Michal Wilczynski <m.wilczynski@...sung.com>
To: Matt Coster <Matt.Coster@...tec.com>, Drew Fustini <drew@...7.com>
Cc: Guo Ren <guoren@...nel.org>, Fu Wei <wefu@...hat.com>, Rob Herring
	<robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley
	<conor+dt@...nel.org>, Bartosz Golaszewski <brgl@...ev.pl>, Philipp Zabel
	<p.zabel@...gutronix.de>, Frank Binns <Frank.Binns@...tec.com>, Maarten
	Lankhorst <maarten.lankhorst@...ux.intel.com>, Maxime Ripard
	<mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>, David Airlie
	<airlied@...il.com>, Simona Vetter <simona@...ll.ch>, Paul Walmsley
	<paul.walmsley@...ive.com>, Palmer Dabbelt <palmer@...belt.com>, Albert Ou
	<aou@...s.berkeley.edu>, Alexandre Ghiti <alex@...ti.fr>, Ulf Hansson
	<ulf.hansson@...aro.org>, Marek Szyprowski <m.szyprowski@...sung.com>, Drew
	Fustini <fustini@...nel.org>, "linux-riscv@...ts.infradead.org"
	<linux-riscv@...ts.infradead.org>, "devicetree@...r.kernel.org"
	<devicetree@...r.kernel.org>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>, "linux-pm@...r.kernel.org"
	<linux-pm@...r.kernel.org>, "dri-devel@...ts.freedesktop.org"
	<dri-devel@...ts.freedesktop.org>
Subject: Re: [PATCH v13 1/4] drm/imagination: Use pwrseq for TH1520 GPU
 power management



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@...sung.com>
>>
>> Reviewed-by: Matt Coster <matt.coster@...tec.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 ?

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,
-- 
Michal Wilczynski <m.wilczynski@...sung.com>

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