drm/panthor: Add the GPU logical block

Handles everything that's not related to the FW, the MMU or the
scheduler. This is the block dealing with the GPU property retrieval,
the GPU block power on/off logic, and some global operations, like
global cache flushing.

v6:
- Add Maxime's and Heiko's acks

v5:
- Fix GPU_MODEL() kernel doc
- Fix test in panthor_gpu_block_power_off()
- Add Steve's R-b

v4:
- Expose CORE_FEATURES through DEV_QUERY

v3:
- Add acks for the MIT/GPL2 relicensing
- Use macros to extract GPU ID info
- Make sure we reset clear pending_reqs bits when wait_event_timeout()
  times out but the corresponding bit is cleared in GPU_INT_RAWSTAT
  (can happen if the IRQ is masked or HW takes to long to call the IRQ
  handler)
- GPU_MODEL now takes separate arch and product majors to be more
  readable.
- Drop GPU_IRQ_MCU_STATUS_CHANGED from interrupt mask.
- Handle GPU_IRQ_PROTM_FAULT correctly (don't output registers that are
  not updated for protected interrupts).
- Minor code tidy ups

Cc: Alexey Sheplyakov <asheplyakov@basealt.ru> # MIT+GPL2 relicensing
Co-developed-by: Steven Price <steven.price@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Acked-by: Steven Price <steven.price@arm.com> # MIT+GPL2 relicensing,Arm
Acked-by: Grant Likely <grant.likely@linaro.org> # MIT+GPL2 relicensing,Linaro
Acked-by: Boris Brezillon <boris.brezillon@collabora.com> # MIT+GPL2 relicensing,Collabora
Reviewed-by: Steven Price <steven.price@arm.com>
Acked-by: Maxime Ripard <mripard@kernel.org>
Acked-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20240229162230.2634044-5-boris.brezillon@collabora.com

drivers/gpu/drm/panthor/panthor_gpu.h

+/* SPDX-License-Identifier: GPL-2.0 or MIT */
+/* Copyright 2018 Marty E. Plummer <hanetzer@startmail.com> */
+/* Copyright 2019 Collabora ltd. */
+
+#ifndef __PANTHOR_GPU_H__
+#define __PANTHOR_GPU_H__
+
+struct panthor_device;
+
+int panthor_gpu_init(struct panthor_device *ptdev);
+void panthor_gpu_unplug(struct panthor_device *ptdev);
+void panthor_gpu_suspend(struct panthor_device *ptdev);
+void panthor_gpu_resume(struct panthor_device *ptdev);
+
+int panthor_gpu_block_power_on(struct panthor_device *ptdev,
+			       const char *blk_name,
+			       u32 pwron_reg, u32 pwrtrans_reg,
+			       u32 rdy_reg, u64 mask, u32 timeout_us);
+int panthor_gpu_block_power_off(struct panthor_device *ptdev,
+				const char *blk_name,
+				u32 pwroff_reg, u32 pwrtrans_reg,
+				u64 mask, u32 timeout_us);
+
+/**
+ * panthor_gpu_power_on() - Power on the GPU block.
+ *
+ * Return: 0 on success, a negative error code otherwise.
+ */
+#define panthor_gpu_power_on(ptdev, type, mask, timeout_us) \
+	panthor_gpu_block_power_on(ptdev, #type, \
+				  type ## _PWRON_LO, \
+				  type ## _PWRTRANS_LO, \
+				  type ## _READY_LO, \
+				  mask, timeout_us)
+
+/**
+ * panthor_gpu_power_off() - Power off the GPU block.
+ *
+ * Return: 0 on success, a negative error code otherwise.
+ */
+#define panthor_gpu_power_off(ptdev, type, mask, timeout_us) \
+	panthor_gpu_block_power_off(ptdev, #type, \
+				   type ## _PWROFF_LO, \
+				   type ## _PWRTRANS_LO, \
+				   mask, timeout_us)
+
+int panthor_gpu_l2_power_on(struct panthor_device *ptdev);
+int panthor_gpu_flush_caches(struct panthor_device *ptdev,
+			     u32 l2, u32 lsc, u32 other);
+int panthor_gpu_soft_reset(struct panthor_device *ptdev);
+
+#endif