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Message-ID: <fbb5af8e-bce6-43d0-b88f-006c968d3600@arm.com>
Date: Mon, 20 Oct 2025 10:40:29 +0100
From: Steven Price <steven.price@....com>
To: Karunika Choo <karunika.choo@....com>, dri-devel@...ts.freedesktop.org
Cc: nd@....com, Boris Brezillon <boris.brezillon@...labora.com>,
Liviu Dudau <liviu.dudau@....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>,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 05/10] drm/panthor: Introduce panthor_pwr API and power
control framework
On 14/10/2025 10:43, Karunika Choo wrote:
> Add the new panthor_pwr module, which provides basic power control
> management for Mali-G1 GPUs. The initial implementation includes
> infrastructure for initializing the PWR_CONTROL block, requesting and
> handling its IRQ, and defining the PANTHOR_HW_FEATURE_PWR_CONTROL
> feature flag.
>
> The patch also integrates panthor_pwr with the device lifecycle (init,
> suspend, resume, and unplug) through the new API functions. It also
> registers the IRQ handler under the 'gpu' IRQ as the PWR_CONTROL block
> is located within the GPU_CONTROL block.
>
> Signed-off-by: Karunika Choo <karunika.choo@....com>
Mostlt looks good - two minor comments below.
> ---
> drivers/gpu/drm/panthor/Makefile | 1 +
> drivers/gpu/drm/panthor/panthor_device.c | 14 ++-
> drivers/gpu/drm/panthor/panthor_device.h | 4 +
> drivers/gpu/drm/panthor/panthor_hw.h | 3 +
> drivers/gpu/drm/panthor/panthor_pwr.c | 135 +++++++++++++++++++++++
> drivers/gpu/drm/panthor/panthor_pwr.h | 23 ++++
> drivers/gpu/drm/panthor/panthor_regs.h | 79 +++++++++++++
> 7 files changed, 258 insertions(+), 1 deletion(-)
> create mode 100644 drivers/gpu/drm/panthor/panthor_pwr.c
> create mode 100644 drivers/gpu/drm/panthor/panthor_pwr.h
>
> diff --git a/drivers/gpu/drm/panthor/Makefile b/drivers/gpu/drm/panthor/Makefile
> index 02db21748c12..753a32c446df 100644
> --- a/drivers/gpu/drm/panthor/Makefile
> +++ b/drivers/gpu/drm/panthor/Makefile
> @@ -10,6 +10,7 @@ panthor-y := \
> panthor_heap.o \
> panthor_hw.o \
> panthor_mmu.o \
> + panthor_pwr.o \
> panthor_sched.o
>
> obj-$(CONFIG_DRM_PANTHOR) += panthor.o
> diff --git a/drivers/gpu/drm/panthor/panthor_device.c b/drivers/gpu/drm/panthor/panthor_device.c
> index 847dea458682..d3e16da0b24e 100644
> --- a/drivers/gpu/drm/panthor/panthor_device.c
> +++ b/drivers/gpu/drm/panthor/panthor_device.c
> @@ -20,6 +20,7 @@
> #include "panthor_gpu.h"
> #include "panthor_hw.h"
> #include "panthor_mmu.h"
> +#include "panthor_pwr.h"
> #include "panthor_regs.h"
> #include "panthor_sched.h"
>
> @@ -102,6 +103,7 @@ void panthor_device_unplug(struct panthor_device *ptdev)
> panthor_fw_unplug(ptdev);
> panthor_mmu_unplug(ptdev);
> panthor_gpu_unplug(ptdev);
> + panthor_pwr_unplug(ptdev);
>
> pm_runtime_dont_use_autosuspend(ptdev->base.dev);
> pm_runtime_put_sync_suspend(ptdev->base.dev);
> @@ -249,10 +251,14 @@ int panthor_device_init(struct panthor_device *ptdev)
> if (ret)
> goto err_rpm_put;
>
> - ret = panthor_gpu_init(ptdev);
> + ret = panthor_pwr_init(ptdev);
> if (ret)
> goto err_rpm_put;
>
> + ret = panthor_gpu_init(ptdev);
> + if (ret)
> + goto err_unplug_pwr;
> +
> ret = panthor_gpu_coherency_init(ptdev);
> if (ret)
> goto err_unplug_gpu;
> @@ -293,6 +299,9 @@ int panthor_device_init(struct panthor_device *ptdev)
> err_unplug_gpu:
> panthor_gpu_unplug(ptdev);
>
> +err_unplug_pwr:
> + panthor_pwr_unplug(ptdev);
> +
> err_rpm_put:
> pm_runtime_put_sync_suspend(ptdev->base.dev);
> return ret;
> @@ -446,6 +455,7 @@ static int panthor_device_resume_hw_components(struct panthor_device *ptdev)
> {
> int ret;
>
> + panthor_pwr_resume(ptdev);
> panthor_gpu_resume(ptdev);
> panthor_mmu_resume(ptdev);
>
> @@ -455,6 +465,7 @@ static int panthor_device_resume_hw_components(struct panthor_device *ptdev)
>
> panthor_mmu_suspend(ptdev);
> panthor_gpu_suspend(ptdev);
> + panthor_pwr_suspend(ptdev);
> return ret;
> }
>
> @@ -568,6 +579,7 @@ int panthor_device_suspend(struct device *dev)
> panthor_fw_suspend(ptdev);
> panthor_mmu_suspend(ptdev);
> panthor_gpu_suspend(ptdev);
> + panthor_pwr_suspend(ptdev);
> drm_dev_exit(cookie);
> }
>
> diff --git a/drivers/gpu/drm/panthor/panthor_device.h b/drivers/gpu/drm/panthor/panthor_device.h
> index 1457c1255f1f..05818318e0ba 100644
> --- a/drivers/gpu/drm/panthor/panthor_device.h
> +++ b/drivers/gpu/drm/panthor/panthor_device.h
> @@ -31,6 +31,7 @@ struct panthor_job;
> struct panthor_mmu;
> struct panthor_fw;
> struct panthor_perfcnt;
> +struct panthor_pwr;
> struct panthor_vm;
> struct panthor_vm_pool;
>
> @@ -126,6 +127,9 @@ struct panthor_device {
> /** @hw: GPU-specific data. */
> struct panthor_hw *hw;
>
> + /** @pwr: Power control management data. */
> + struct panthor_pwr *pwr;
> +
> /** @gpu: GPU management data. */
> struct panthor_gpu *gpu;
>
> diff --git a/drivers/gpu/drm/panthor/panthor_hw.h b/drivers/gpu/drm/panthor/panthor_hw.h
> index 5a4e4aad9099..caba522cd680 100644
> --- a/drivers/gpu/drm/panthor/panthor_hw.h
> +++ b/drivers/gpu/drm/panthor/panthor_hw.h
> @@ -15,6 +15,9 @@ struct panthor_device;
> * New feature flags will be added with support for newer GPU architectures.
> */
> enum panthor_hw_feature {
> + /** @PANTHOR_HW_FEATURE_PWR_CONTROL: HW supports the PWR_CONTROL interface. */
> + PANTHOR_HW_FEATURE_PWR_CONTROL,
> +
> /** @PANTHOR_HW_FEATURES_END: Must be last. */
> PANTHOR_HW_FEATURES_END
> };
> diff --git a/drivers/gpu/drm/panthor/panthor_pwr.c b/drivers/gpu/drm/panthor/panthor_pwr.c
> new file mode 100644
> index 000000000000..d07ad5b7953a
> --- /dev/null
> +++ b/drivers/gpu/drm/panthor/panthor_pwr.c
> @@ -0,0 +1,135 @@
> +// SPDX-License-Identifier: GPL-2.0 or MIT
> +/* Copyright 2025 ARM Limited. All rights reserved. */
> +
> +#include <linux/platform_device.h>
> +#include <linux/interrupt.h>
> +#include <linux/iopoll.h>
> +#include <linux/wait.h>
> +
> +#include <drm/drm_managed.h>
> +
> +#include "panthor_device.h"
> +#include "panthor_hw.h"
> +#include "panthor_pwr.h"
> +#include "panthor_regs.h"
> +
> +#define PWR_INTERRUPTS_MASK \
> + (PWR_IRQ_POWER_CHANGED_SINGLE | \
> + PWR_IRQ_POWER_CHANGED_ALL | \
> + PWR_IRQ_DELEGATION_CHANGED | \
> + PWR_IRQ_RESET_COMPLETED | \
> + PWR_IRQ_RETRACT_COMPLETED | \
> + PWR_IRQ_INSPECT_COMPLETED | \
> + PWR_IRQ_COMMAND_NOT_ALLOWED | \
> + PWR_IRQ_COMMAND_INVALID)
> +
> +/**
> + * struct panthor_pwr - PWR_CONTROL block management data.
> + */
> +struct panthor_pwr {
> + /** @irq: PWR irq. */
> + struct panthor_irq irq;
> +
> + /** @reqs_lock: Lock protecting access to pending_reqs. */
> + spinlock_t reqs_lock;
> +
> + /** @pending_reqs: Pending PWR requests. */
> + u32 pending_reqs;
> +
> + /** @reqs_acked: PWR request wait queue. */
> + wait_queue_head_t reqs_acked;
> +};
> +
> +static void panthor_pwr_irq_handler(struct panthor_device *ptdev, u32 status)
> +{
> + spin_lock(&ptdev->pwr->reqs_lock);
> + gpu_write(ptdev, PWR_INT_CLEAR, status);
> +
> + if (unlikely(status & PWR_IRQ_COMMAND_NOT_ALLOWED))
> + drm_err(&ptdev->base, "PWR_IRQ: COMMAND_NOT_ALLOWED");
> +
> + if (unlikely(status & PWR_IRQ_COMMAND_INVALID))
> + drm_err(&ptdev->base, "PWR_IRQ: COMMAND_INVALID");
> +
> + if (status & ptdev->pwr->pending_reqs) {
> + ptdev->pwr->pending_reqs &= ~status;
> + wake_up_all(&ptdev->pwr->reqs_acked);
> + }
> + spin_unlock(&ptdev->pwr->reqs_lock);
> +}
> +PANTHOR_IRQ_HANDLER(pwr, PWR, panthor_pwr_irq_handler);
> +
> +void panthor_pwr_unplug(struct panthor_device *ptdev)
> +{
> + unsigned long flags;
> +
> + if (!ptdev->pwr)
> + return;
> +
> + /* Make sure the IRQ handler is not running after that point. */
> + panthor_pwr_irq_suspend(&ptdev->pwr->irq);
> +
> + /* Wake-up all waiters. */
> + spin_lock_irqsave(&ptdev->pwr->reqs_lock, flags);
> + ptdev->pwr->pending_reqs = 0;
> + wake_up_all(&ptdev->pwr->reqs_acked);
> + spin_unlock_irqrestore(&ptdev->pwr->reqs_lock, flags);
> +}
> +
> +int panthor_pwr_init(struct panthor_device *ptdev)
> +{
> + struct panthor_pwr *pwr;
> + int err, irq;
> +
> + if (!panthor_hw_has_feature(ptdev, PANTHOR_HW_FEATURE_PWR_CONTROL))
> + return 0;
> +
> + pwr = drmm_kzalloc(&ptdev->base, sizeof(*pwr), GFP_KERNEL);
> + if (!pwr)
> + return -ENOMEM;
> +
> + spin_lock_init(&pwr->reqs_lock);
> + init_waitqueue_head(&pwr->reqs_acked);
> + ptdev->pwr = pwr;
> +
> + irq = platform_get_irq_byname(to_platform_device(ptdev->base.dev), "gpu");
> + if (irq < 0)
> + return irq;
> +
> + err = panthor_request_pwr_irq(ptdev, &pwr->irq, irq, PWR_INTERRUPTS_MASK);
> + if (err)
> + return err;
> +
> + return 0;
> +}
> +
> +int panthor_pwr_reset_soft(struct panthor_device *ptdev)
> +{
> + return 0;
> +}
> +
> +int panthor_pwr_l2_power_off(struct panthor_device *ptdev)
> +{
> + return 0;
> +}
> +
> +int panthor_pwr_l2_power_on(struct panthor_device *ptdev)
> +{
> + return 0;
> +}
I don't see any need to add these dummy functions - just add the full
implementation in the next patch.
> +
> +void panthor_pwr_suspend(struct panthor_device *ptdev)
> +{
> + if (!ptdev->pwr)
> + return;
> +
> + panthor_pwr_irq_suspend(&ptdev->pwr->irq);
> +}
> +
> +void panthor_pwr_resume(struct panthor_device *ptdev)
> +{
> + if (!ptdev->pwr)
> + return;
> +
> + panthor_pwr_irq_resume(&ptdev->pwr->irq, PWR_INTERRUPTS_MASK);
> +}
> diff --git a/drivers/gpu/drm/panthor/panthor_pwr.h b/drivers/gpu/drm/panthor/panthor_pwr.h
> new file mode 100644
> index 000000000000..a4042c125448
> --- /dev/null
> +++ b/drivers/gpu/drm/panthor/panthor_pwr.h
> @@ -0,0 +1,23 @@
> +/* SPDX-License-Identifier: GPL-2.0 or MIT */
> +/* Copyright 2025 ARM Limited. All rights reserved. */
> +
> +#ifndef __PANTHOR_PWR_H__
> +#define __PANTHOR_PWR_H__
> +
> +struct panthor_device;
> +
> +void panthor_pwr_unplug(struct panthor_device *ptdev);
> +
> +int panthor_pwr_init(struct panthor_device *ptdev);
> +
> +int panthor_pwr_reset_soft(struct panthor_device *ptdev);
> +
> +int panthor_pwr_l2_power_on(struct panthor_device *ptdev);
> +
> +int panthor_pwr_l2_power_off(struct panthor_device *ptdev);
> +
> +void panthor_pwr_suspend(struct panthor_device *ptdev);
> +
> +void panthor_pwr_resume(struct panthor_device *ptdev);
> +
> +#endif /* __PANTHOR_PWR_H__ */
> diff --git a/drivers/gpu/drm/panthor/panthor_regs.h b/drivers/gpu/drm/panthor/panthor_regs.h
> index 8bee76d01bf8..84db97c11e68 100644
> --- a/drivers/gpu/drm/panthor/panthor_regs.h
> +++ b/drivers/gpu/drm/panthor/panthor_regs.h
> @@ -72,6 +72,7 @@
>
> #define GPU_FEATURES 0x60
> #define GPU_FEATURES_RAY_INTERSECTION BIT(2)
> +#define GPU_FEATURES_RAY_TRAVERSAL BIT(5)
This line shouldn't be in this patch.
Thanks,
Steve
>
> #define GPU_TIMESTAMP_OFFSET 0x88
> #define GPU_CYCLE_COUNT 0x90
> @@ -205,4 +206,82 @@
> #define CSF_DOORBELL(i) (0x80000 + ((i) * 0x10000))
> #define CSF_GLB_DOORBELL_ID 0
>
> +/* PWR Control registers */
> +
> +#define PWR_CONTROL_BASE 0x800
> +#define PWR_CTRL_REG(x) (PWR_CONTROL_BASE + (x))
> +
> +#define PWR_INT_RAWSTAT PWR_CTRL_REG(0x0)
> +#define PWR_INT_CLEAR PWR_CTRL_REG(0x4)
> +#define PWR_INT_MASK PWR_CTRL_REG(0x8)
> +#define PWR_INT_STAT PWR_CTRL_REG(0xc)
> +#define PWR_IRQ_POWER_CHANGED_SINGLE BIT(0)
> +#define PWR_IRQ_POWER_CHANGED_ALL BIT(1)
> +#define PWR_IRQ_DELEGATION_CHANGED BIT(2)
> +#define PWR_IRQ_RESET_COMPLETED BIT(3)
> +#define PWR_IRQ_RETRACT_COMPLETED BIT(4)
> +#define PWR_IRQ_INSPECT_COMPLETED BIT(5)
> +#define PWR_IRQ_COMMAND_NOT_ALLOWED BIT(30)
> +#define PWR_IRQ_COMMAND_INVALID BIT(31)
> +
> +#define PWR_STATUS PWR_CTRL_REG(0x20)
> +#define PWR_STATUS_ALLOW_L2 BIT(0)
> +#define PWR_STATUS_ALLOW_TILER BIT(1)
> +#define PWR_STATUS_ALLOW_SHADER BIT(8)
> +#define PWR_STATUS_ALLOW_BASE BIT(14)
> +#define PWR_STATUS_ALLOW_STACK BIT(15)
> +#define PWR_STATUS_DOMAIN_ALLOWED(x) (1 << (x))
> +#define PWR_STATUS_DELEGATED_L2 BIT(16)
> +#define PWR_STATUS_DELEGATED_TILER BIT(17)
> +#define PWR_STATUS_DELEGATED_SHADER BIT(24)
> +#define PWR_STATUS_DELEGATED_BASE BIT(30)
> +#define PWR_STATUS_DELEGATED_STACK BIT(31)
> +#define PWR_STATUS_DELEGATED_SHIFT 16
> +#define PWR_STATUS_DOMAIN_DELEGATED(x) (1 << ((x) + PWR_STATUS_DELEGATED_SHIFT))
> +#define PWR_STATUS_ALLOW_SOFT_RESET BIT(33)
> +#define PWR_STATUS_ALLOW_FAST_RESET BIT(34)
> +#define PWR_STATUS_POWER_PENDING BIT(41)
> +#define PWR_STATUS_RESET_PENDING BIT(42)
> +#define PWR_STATUS_RETRACT_PENDING BIT(43)
> +#define PWR_STATUS_INSPECT_PENDING BIT(44)
> +
> +#define PWR_COMMAND PWR_CTRL_REG(0x28)
> +#define PWR_COMMAND_POWER_UP 0x10
> +#define PWR_COMMAND_POWER_DOWN 0x11
> +#define PWR_COMMAND_DELEGATE 0x20
> +#define PWR_COMMAND_RETRACT 0x21
> +#define PWR_COMMAND_RESET_SOFT 0x31
> +#define PWR_COMMAND_RESET_FAST 0x32
> +#define PWR_COMMAND_INSPECT 0xF0
> +#define PWR_COMMAND_DOMAIN_L2 0
> +#define PWR_COMMAND_DOMAIN_TILER 1
> +#define PWR_COMMAND_DOMAIN_SHADER 8
> +#define PWR_COMMAND_DOMAIN_BASE 14
> +#define PWR_COMMAND_DOMAIN_STACK 15
> +#define PWR_COMMAND_SUBDOMAIN_RTU BIT(0)
> +#define PWR_COMMAND_DEF(cmd, domain, subdomain) \
> + (((subdomain) << 16) | ((domain) << 8) | (cmd))
> +
> +#define PWR_CMDARG PWR_CTRL_REG(0x30)
> +
> +#define PWR_L2_PRESENT PWR_CTRL_REG(0x100)
> +#define PWR_L2_READY PWR_CTRL_REG(0x108)
> +#define PWR_L2_PWRTRANS PWR_CTRL_REG(0x110)
> +#define PWR_L2_PWRACTIVE PWR_CTRL_REG(0x118)
> +#define PWR_TILER_PRESENT PWR_CTRL_REG(0x140)
> +#define PWR_TILER_READY PWR_CTRL_REG(0x148)
> +#define PWR_TILER_PWRTRANS PWR_CTRL_REG(0x150)
> +#define PWR_TILER_PWRACTIVE PWR_CTRL_REG(0x158)
> +#define PWR_SHADER_PRESENT PWR_CTRL_REG(0x200)
> +#define PWR_SHADER_READY PWR_CTRL_REG(0x208)
> +#define PWR_SHADER_PWRTRANS PWR_CTRL_REG(0x210)
> +#define PWR_SHADER_PWRACTIVE PWR_CTRL_REG(0x218)
> +#define PWR_BASE_PRESENT PWR_CTRL_REG(0x380)
> +#define PWR_BASE_READY PWR_CTRL_REG(0x388)
> +#define PWR_BASE_PWRTRANS PWR_CTRL_REG(0x390)
> +#define PWR_BASE_PWRACTIVE PWR_CTRL_REG(0x398)
> +#define PWR_STACK_PRESENT PWR_CTRL_REG(0x3c0)
> +#define PWR_STACK_READY PWR_CTRL_REG(0x3c8)
> +#define PWR_STACK_PWRTRANS PWR_CTRL_REG(0x3d0)
> +
> #endif
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