drm/imagination: Get GPU resources

Acquire clock and register resources, and enable/map as appropriate.

Changes since v8:
- Corrected license identifiers

Changes since v3:
- Remove regulator resource (not used on supported platform)
- Use devm helpers
- Use devm_clk_get_optional() for optional clocks
- Don't prepare clocks on resource acquisition
- Drop pvr_device_clk_core_get_freq() helper
- Drop pvr_device_reg_fini()
- Drop NULLing of clocks in pvr_device_clk_init()
- Use dev_err_probe() on clock acquisition failure
- Remove PVR_CR_READ/WRITE helper macros
- Improve documentation for GPU clocks
- Remove regs resource (not used in this commit)

Co-developed-by: Frank Binns <frank.binns@imgtec.com>
Signed-off-by: Frank Binns <frank.binns@imgtec.com>
Co-developed-by: Matt Coster <matt.coster@imgtec.com>
Signed-off-by: Matt Coster <matt.coster@imgtec.com>
Signed-off-by: Sarah Walker <sarah.walker@imgtec.com>
Signed-off-by: Donald Robson <donald.robson@imgtec.com>
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Link: https://lore.kernel.org/r/579027bd5be4eb3218c9784050ded2326ecbc352.1700668843.git.donald.robson@imgtec.com
Signed-off-by: Maxime Ripard <mripard@kernel.org>

drivers/gpu/drm/imagination/Makefile

@@ -4,6 +4,7 @@
 subdir-ccflags-y := -I$(srctree)/$(src)
 
 powervr-y := \
+	pvr_device.o \
 	pvr_drv.o \
 
 obj-$(CONFIG_DRM_POWERVR) += powervr.o

drivers/gpu/drm/imagination/pvr_device.c

@@ -0,0 +1,147 @@
+// SPDX-License-Identifier: GPL-2.0-only OR MIT
+/* Copyright (c) 2023 Imagination Technologies Ltd. */
+
+#include "pvr_device.h"
+
+#include <drm/drm_print.h>
+
+#include <linux/clk.h>
+#include <linux/compiler_attributes.h>
+#include <linux/compiler_types.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/gfp.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/stddef.h>
+#include <linux/types.h>
+
+/**
+ * pvr_device_reg_init() - Initialize kernel access to a PowerVR device's
+ * control registers.
+ * @pvr_dev: Target PowerVR device.
+ *
+ * Sets struct pvr_device->regs.
+ *
+ * This method of mapping the device control registers into memory ensures that
+ * they are unmapped when the driver is detached (i.e. no explicit cleanup is
+ * required).
+ *
+ * Return:
+ *  * 0 on success, or
+ *  * Any error returned by devm_platform_ioremap_resource().
+ */
+static int
+pvr_device_reg_init(struct pvr_device *pvr_dev)
+{
+	struct drm_device *drm_dev = from_pvr_device(pvr_dev);
+	struct platform_device *plat_dev = to_platform_device(drm_dev->dev);
+	void __iomem *regs;
+
+	pvr_dev->regs = NULL;
+
+	regs = devm_platform_ioremap_resource(plat_dev, 0);
+	if (IS_ERR(regs))
+		return dev_err_probe(drm_dev->dev, PTR_ERR(regs),
+				     "failed to ioremap gpu registers\n");
+
+	pvr_dev->regs = regs;
+
+	return 0;
+}
+
+/**
+ * pvr_device_clk_init() - Initialize clocks required by a PowerVR device
+ * @pvr_dev: Target PowerVR device.
+ *
+ * Sets struct pvr_device->core_clk, struct pvr_device->sys_clk and
+ * struct pvr_device->mem_clk.
+ *
+ * Three clocks are required by the PowerVR device: core, sys and mem. On
+ * return, this function guarantees that the clocks are in one of the following
+ * states:
+ *
+ *  * All successfully initialized,
+ *  * Core errored, sys and mem uninitialized,
+ *  * Core deinitialized, sys errored, mem uninitialized, or
+ *  * Core and sys deinitialized, mem errored.
+ *
+ * Return:
+ *  * 0 on success,
+ *  * Any error returned by devm_clk_get(), or
+ *  * Any error returned by devm_clk_get_optional().
+ */
+static int pvr_device_clk_init(struct pvr_device *pvr_dev)
+{
+	struct drm_device *drm_dev = from_pvr_device(pvr_dev);
+	struct clk *core_clk;
+	struct clk *sys_clk;
+	struct clk *mem_clk;
+
+	core_clk = devm_clk_get(drm_dev->dev, "core");
+	if (IS_ERR(core_clk))
+		return dev_err_probe(drm_dev->dev, PTR_ERR(core_clk),
+				     "failed to get core clock\n");
+
+	sys_clk = devm_clk_get_optional(drm_dev->dev, "sys");
+	if (IS_ERR(sys_clk))
+		return dev_err_probe(drm_dev->dev, PTR_ERR(core_clk),
+				     "failed to get sys clock\n");
+
+	mem_clk = devm_clk_get_optional(drm_dev->dev, "mem");
+	if (IS_ERR(mem_clk))
+		return dev_err_probe(drm_dev->dev, PTR_ERR(core_clk),
+				     "failed to get mem clock\n");
+
+	pvr_dev->core_clk = core_clk;
+	pvr_dev->sys_clk = sys_clk;
+	pvr_dev->mem_clk = mem_clk;
+
+	return 0;
+}
+
+/**
+ * pvr_device_init() - Initialize a PowerVR device
+ * @pvr_dev: Target PowerVR device.
+ *
+ * If this function returns successfully, the device will have been fully
+ * initialized. Otherwise, any parts of the device initialized before an error
+ * occurs will be de-initialized before returning.
+ *
+ * NOTE: The initialization steps currently taken are the bare minimum required
+ *       to read from the control registers. The device is unlikely to function
+ *       until further initialization steps are added. [This note should be
+ *       removed when that happens.]
+ *
+ * Return:
+ *  * 0 on success,
+ *  * Any error returned by pvr_device_reg_init(),
+ *  * Any error returned by pvr_device_clk_init(), or
+ *  * Any error returned by pvr_device_gpu_init().
+ */
+int
+pvr_device_init(struct pvr_device *pvr_dev)
+{
+	int err;
+
+	/* Enable and initialize clocks required for the device to operate. */
+	err = pvr_device_clk_init(pvr_dev);
+	if (err)
+		return err;
+
+	/* Map the control registers into memory. */
+	return pvr_device_reg_init(pvr_dev);
+}
+
+/**
+ * pvr_device_fini() - Deinitialize a PowerVR device
+ * @pvr_dev: Target PowerVR device.
+ */
+void
+pvr_device_fini(struct pvr_device *pvr_dev)
+{
+	/*
+	 * Deinitialization stages are performed in reverse order compared to
+	 * the initialization stages in pvr_device_init().
+	 */
+}

drivers/gpu/drm/imagination/pvr_device.h

@@ -11,9 +11,22 @@
 #include <linux/bits.h>
 #include <linux/compiler_attributes.h>
 #include <linux/compiler_types.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
 #include <linux/kernel.h>
+#include <linux/math.h>
+#include <linux/mutex.h>
+#include <linux/timer.h>
 #include <linux/types.h>
 #include <linux/wait.h>
+#include <linux/workqueue.h>
+#include <linux/xarray.h>
+
+/* Forward declaration from <linux/clk.h>. */
+struct clk;
+
+/* Forward declaration from <linux/firmware.h>. */
+struct firmware;
 
 /**
  * struct pvr_device - powervr-specific wrapper for &struct drm_device
@@ -26,6 +39,37 @@ struct pvr_device {
 	 * from_pvr_device().
 	 */
 	struct drm_device base;
+
+	/**
+	 * @regs: Device control registers.
+	 *
+	 * These are mapped into memory when the device is initialized; that
+	 * location is where this pointer points.
+	 */
+	void __iomem *regs;
+
+	/**
+	 * @core_clk: General core clock.
+	 *
+	 * This is the primary clock used by the entire GPU core.
+	 */
+	struct clk *core_clk;
+
+	/**
+	 * @sys_clk: Optional system bus clock.
+	 *
+	 * This may be used on some platforms to provide an independent clock to the SoC Interface
+	 * (SOCIF). If present, this needs to be enabled/disabled together with @core_clk.
+	 */
+	struct clk *sys_clk;
+
+	/**
+	 * @mem_clk: Optional memory clock.
+	 *
+	 * This may be used on some platforms to provide an independent clock to the Memory
+	 * Interface (MEMIF). If present, this needs to be enabled/disabled together with @core_clk.
+	 */
+	struct clk *mem_clk;
 };
 
 /**
@@ -56,6 +100,114 @@ struct pvr_file {
 
 #define to_pvr_file(file) ((file)->driver_priv)
 
+int pvr_device_init(struct pvr_device *pvr_dev);
+void pvr_device_fini(struct pvr_device *pvr_dev);
+
+/**
+ * PVR_CR_FIELD_GET() - Extract a single field from a PowerVR control register
+ * @val: Value of the target register.
+ * @field: Field specifier, as defined in "pvr_rogue_cr_defs.h".
+ *
+ * Return: The extracted field.
+ */
+#define PVR_CR_FIELD_GET(val, field) FIELD_GET(~ROGUE_CR_##field##_CLRMSK, val)
+
+/**
+ * pvr_cr_read32() - Read a 32-bit register from a PowerVR device
+ * @pvr_dev: Target PowerVR device.
+ * @reg: Target register.
+ *
+ * Return: The value of the requested register.
+ */
+static __always_inline u32
+pvr_cr_read32(struct pvr_device *pvr_dev, u32 reg)
+{
+	return ioread32(pvr_dev->regs + reg);
+}
+
+/**
+ * pvr_cr_read64() - Read a 64-bit register from a PowerVR device
+ * @pvr_dev: Target PowerVR device.
+ * @reg: Target register.
+ *
+ * Return: The value of the requested register.
+ */
+static __always_inline u64
+pvr_cr_read64(struct pvr_device *pvr_dev, u32 reg)
+{
+	return ioread64(pvr_dev->regs + reg);
+}
+
+/**
+ * pvr_cr_write32() - Write to a 32-bit register in a PowerVR device
+ * @pvr_dev: Target PowerVR device.
+ * @reg: Target register.
+ * @val: Value to write.
+ */
+static __always_inline void
+pvr_cr_write32(struct pvr_device *pvr_dev, u32 reg, u32 val)
+{
+	iowrite32(val, pvr_dev->regs + reg);
+}
+
+/**
+ * pvr_cr_write64() - Write to a 64-bit register in a PowerVR device
+ * @pvr_dev: Target PowerVR device.
+ * @reg: Target register.
+ * @val: Value to write.
+ */
+static __always_inline void
+pvr_cr_write64(struct pvr_device *pvr_dev, u32 reg, u64 val)
+{
+	iowrite64(val, pvr_dev->regs + reg);
+}
+
+/**
+ * pvr_cr_poll_reg32() - Wait for a 32-bit register to match a given value by
+ *                       polling
+ * @pvr_dev: Target PowerVR device.
+ * @reg_addr: Address of register.
+ * @reg_value: Expected register value (after masking).
+ * @reg_mask: Mask of bits valid for comparison with @reg_value.
+ * @timeout_usec: Timeout length, in us.
+ *
+ * Returns:
+ *  * 0 on success, or
+ *  * -%ETIMEDOUT on timeout.
+ */
+static __always_inline int
+pvr_cr_poll_reg32(struct pvr_device *pvr_dev, u32 reg_addr, u32 reg_value,
+		  u32 reg_mask, u64 timeout_usec)
+{
+	u32 value;
+
+	return readl_poll_timeout(pvr_dev->regs + reg_addr, value,
+		(value & reg_mask) == reg_value, 0, timeout_usec);
+}
+
+/**
+ * pvr_cr_poll_reg64() - Wait for a 64-bit register to match a given value by
+ *                       polling
+ * @pvr_dev: Target PowerVR device.
+ * @reg_addr: Address of register.
+ * @reg_value: Expected register value (after masking).
+ * @reg_mask: Mask of bits valid for comparison with @reg_value.
+ * @timeout_usec: Timeout length, in us.
+ *
+ * Returns:
+ *  * 0 on success, or
+ *  * -%ETIMEDOUT on timeout.
+ */
+static __always_inline int
+pvr_cr_poll_reg64(struct pvr_device *pvr_dev, u32 reg_addr, u64 reg_value,
+		  u64 reg_mask, u64 timeout_usec)
+{
+	u64 value;
+
+	return readq_poll_timeout(pvr_dev->regs + reg_addr, value,
+		(value & reg_mask) == reg_value, 0, timeout_usec);
+}
+
 /**
  * DOC: IOCTL validation helpers
  *

drivers/gpu/drm/imagination/pvr_drv.c

@@ -464,6 +464,7 @@ pvr_probe(struct platform_device *plat_dev)
 {
 	struct pvr_device *pvr_dev;
 	struct drm_device *drm_dev;
+	int err;
 
 	pvr_dev = devm_drm_dev_alloc(&plat_dev->dev, &pvr_drm_driver,
 				     struct pvr_device, base);
@@ -474,14 +475,29 @@ pvr_probe(struct platform_device *plat_dev)
 
 	platform_set_drvdata(plat_dev, drm_dev);
 
-	return drm_dev_register(drm_dev, 0);
+	err = pvr_device_init(pvr_dev);
+	if (err)
+		return err;
+
+	err = drm_dev_register(drm_dev, 0);
+	if (err)
+		goto err_device_fini;
+
+	return 0;
+
+err_device_fini:
+	pvr_device_fini(pvr_dev);
+
+	return err;
 }
 
 static int
 pvr_remove(struct platform_device *plat_dev)
 {
 	struct drm_device *drm_dev = platform_get_drvdata(plat_dev);
+	struct pvr_device *pvr_dev = to_pvr_device(drm_dev);
 
+	pvr_device_fini(pvr_dev);
 	drm_dev_unplug(drm_dev);
 
 	return 0;