drm/panthor: Introduce panthor_pwr API and power control framework

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 checking for PWR_CONTROL support based on GPU
architecture.

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.

Reviewed-by: Steven Price <[e-mail]>
Signed-off-by: Karunika Choo <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Boris Brezillon <[e-mail]>

drivers/gpu/drm/panthor/Makefile

···
 	panthor_heap.o \
 	panthor_hw.o \
 	panthor_mmu.o \
+	panthor_pwr.o \
 	panthor_sched.o
 
 obj-$(CONFIG_DRM_PANTHOR) += panthor.o

drivers/gpu/drm/panthor/panthor_device.c

···
 #include "panthor_gpu.h"
 #include "panthor_hw.h"
 #include "panthor_mmu.h"
+#include "panthor_pwr.h"
 #include "panthor_regs.h"
 #include "panthor_sched.h"
 
···
 	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);
···
 	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)
···
 
 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);
···
 {
 	int ret;
 
+	panthor_pwr_resume(ptdev);
 	panthor_gpu_resume(ptdev);
 	panthor_mmu_resume(ptdev);
 
···
 
 	panthor_mmu_suspend(ptdev);
 	panthor_gpu_suspend(ptdev);
+	panthor_pwr_suspend(ptdev);
 	return ret;
 }
 
···
 		panthor_fw_suspend(ptdev);
 		panthor_mmu_suspend(ptdev);
 		panthor_gpu_suspend(ptdev);
+		panthor_pwr_suspend(ptdev);
 		drm_dev_exit(cookie);
 	}
 

drivers/gpu/drm/panthor/panthor_device.h

···
 struct panthor_mmu;
 struct panthor_fw;
 struct panthor_perfcnt;
+struct panthor_pwr;
 struct panthor_vm;
 struct panthor_vm_pool;
 
···
 
 	/** @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;

drivers/gpu/drm/panthor/panthor_hw.h

···
 #define __PANTHOR_HW_H__
 
 #include "panthor_device.h"
+#include "panthor_regs.h"
 
 /**
  * struct panthor_hw_ops - HW operations that are specific to a GPU
···
 static inline void panthor_hw_l2_power_off(struct panthor_device *ptdev)
 {
 	ptdev->hw->ops.l2_power_off(ptdev);
+}
+
+static inline bool panthor_hw_has_pwr_ctrl(struct panthor_device *ptdev)
+{
+	return GPU_ARCH_MAJOR(ptdev->gpu_info.gpu_id) >= 14;
 }
 
 #endif /* __PANTHOR_HW_H__ */

drivers/gpu/drm/panthor/panthor_pwr.c

···
+// 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 <drm/drm_print.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_pwr_ctrl(ptdev))
+		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;
+}
+
+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);
+}

drivers/gpu/drm/panthor/panthor_pwr.h

···
+/* 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);
+
+void panthor_pwr_suspend(struct panthor_device *ptdev);
+
+void panthor_pwr_resume(struct panthor_device *ptdev);
+
+#endif /* __PANTHOR_PWR_H__ */

drivers/gpu/drm/panthor/panthor_regs.h

···
 #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_U64(0)
+#define   PWR_STATUS_ALLOW_TILER			BIT_U64(1)
+#define   PWR_STATUS_ALLOW_SHADER			BIT_U64(8)
+#define   PWR_STATUS_ALLOW_BASE				BIT_U64(14)
+#define   PWR_STATUS_ALLOW_STACK			BIT_U64(15)
+#define   PWR_STATUS_DOMAIN_ALLOWED(x)			BIT_U64(x)
+#define   PWR_STATUS_DELEGATED_L2			BIT_U64(16)
+#define   PWR_STATUS_DELEGATED_TILER			BIT_U64(17)
+#define   PWR_STATUS_DELEGATED_SHADER			BIT_U64(24)
+#define   PWR_STATUS_DELEGATED_BASE			BIT_U64(30)
+#define   PWR_STATUS_DELEGATED_STACK			BIT_U64(31)
+#define   PWR_STATUS_DELEGATED_SHIFT			16
+#define   PWR_STATUS_DOMAIN_DELEGATED(x)		BIT_U64((x) + PWR_STATUS_DELEGATED_SHIFT)
+#define   PWR_STATUS_ALLOW_SOFT_RESET			BIT_U64(33)
+#define   PWR_STATUS_ALLOW_FAST_RESET			BIT_U64(34)
+#define   PWR_STATUS_POWER_PENDING			BIT_U64(41)
+#define   PWR_STATUS_RESET_PENDING			BIT_U64(42)
+#define   PWR_STATUS_RETRACT_PENDING			BIT_U64(43)
+#define   PWR_STATUS_INSPECT_PENDING			BIT_U64(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