drivers/soc/qcom/ocmem.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * The On Chip Memory (OCMEM) allocator allows various clients to allocate
  * memory from OCMEM based on performance, latency and power requirements.
  * This is typically used by the GPU, camera/video, and audio components on
  * some Snapdragon SoCs.
  *
  * Copyright (C) 2019 Brian Masney <masneyb@onstation.org>
  * Copyright (C) 2015 Red Hat. Author: Rob Clark <robdclark@gmail.com>
  */

 #include <linux/bitfield.h>
 #include <linux/cleanup.h>
 #include <linux/clk.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
 #include <linux/firmware/qcom/qcom_scm.h>
 #include <linux/sizes.h>
 #include <linux/slab.h>
 #include <linux/types.h>
 #include <soc/qcom/ocmem.h>

 enum region_mode {
 	WIDE_MODE = 0x0,
 	THIN_MODE,
 	MODE_DEFAULT = WIDE_MODE,
 };

 enum ocmem_macro_state {
 	PASSTHROUGH = 0,
 	PERI_ON = 1,
 	CORE_ON = 2,
 	CLK_OFF = 4,
 };

 struct ocmem_region {
 	bool interleaved;
 	enum region_mode mode;
 	unsigned int num_macros;
 	enum ocmem_macro_state macro_state[4];
 	unsigned long macro_size;
 	unsigned long region_size;
 };

 struct ocmem_config {
 	uint8_t num_regions;
 	unsigned long macro_size;
 };

 struct ocmem {
 	struct device *dev;
 	const struct ocmem_config *config;
 	struct resource *memory;
 	void __iomem *mmio;
 	struct clk *core_clk;
 	struct clk *iface_clk;
 	unsigned int num_ports;
 	unsigned int num_macros;
 	bool interleaved;
 	struct ocmem_region *regions;
 	unsigned long active_allocations;
 };

 #define OCMEM_MIN_ALIGN				SZ_64K
 #define OCMEM_MIN_ALLOC				SZ_64K

 #define OCMEM_REG_HW_VERSION			0x00000000
 #define OCMEM_REG_HW_PROFILE			0x00000004

 #define OCMEM_REG_REGION_MODE_CTL		0x00001000
 #define OCMEM_REGION_MODE_CTL_REG0_THIN		0x00000001
 #define OCMEM_REGION_MODE_CTL_REG1_THIN		0x00000002
 #define OCMEM_REGION_MODE_CTL_REG2_THIN		0x00000004
 #define OCMEM_REGION_MODE_CTL_REG3_THIN		0x00000008

 #define OCMEM_REG_GFX_MPU_START			0x00001004
 #define OCMEM_REG_GFX_MPU_END			0x00001008

 #define OCMEM_HW_VERSION_MAJOR(val)		FIELD_GET(GENMASK(31, 28), val)
 #define OCMEM_HW_VERSION_MINOR(val)		FIELD_GET(GENMASK(27, 16), val)
 #define OCMEM_HW_VERSION_STEP(val)		FIELD_GET(GENMASK(15, 0), val)

 #define OCMEM_HW_PROFILE_NUM_PORTS(val)		FIELD_GET(0x0000000f, (val))
 #define OCMEM_HW_PROFILE_NUM_MACROS(val)	FIELD_GET(0x00003f00, (val))

 #define OCMEM_HW_PROFILE_LAST_REGN_HALFSIZE	0x00010000
 #define OCMEM_HW_PROFILE_INTERLEAVING		0x00020000
 #define OCMEM_REG_GEN_STATUS			0x0000000c

 #define OCMEM_REG_PSGSC_STATUS			0x00000038
 #define OCMEM_REG_PSGSC_CTL(i0)			(0x0000003c + 0x1*(i0))

 #define OCMEM_PSGSC_CTL_MACRO0_MODE(val)	FIELD_PREP(0x00000007, (val))
 #define OCMEM_PSGSC_CTL_MACRO1_MODE(val)	FIELD_PREP(0x00000070, (val))
 #define OCMEM_PSGSC_CTL_MACRO2_MODE(val)	FIELD_PREP(0x00000700, (val))
 #define OCMEM_PSGSC_CTL_MACRO3_MODE(val)	FIELD_PREP(0x00007000, (val))

 static inline void ocmem_write(struct ocmem *ocmem, u32 reg, u32 data)
 {
 	writel(data, ocmem->mmio + reg);
 }

 static inline u32 ocmem_read(struct ocmem *ocmem, u32 reg)
 {
 	return readl(ocmem->mmio + reg);
 }

 static void update_ocmem(struct ocmem *ocmem)
 {
 	uint32_t region_mode_ctrl = 0x0;
 	int i;

 	if (!qcom_scm_ocmem_lock_available()) {
 		for (i = 0; i < ocmem->config->num_regions; i++) {
 			struct ocmem_region *region = &ocmem->regions[i];

 			if (region->mode == THIN_MODE)
 				region_mode_ctrl |= BIT(i);
 		}

 		dev_dbg(ocmem->dev, "ocmem_region_mode_control %x\n",
 			region_mode_ctrl);
 		ocmem_write(ocmem, OCMEM_REG_REGION_MODE_CTL, region_mode_ctrl);
 	}

 	for (i = 0; i < ocmem->config->num_regions; i++) {
 		struct ocmem_region *region = &ocmem->regions[i];
 		u32 data;

 		data = OCMEM_PSGSC_CTL_MACRO0_MODE(region->macro_state[0]) |
 			OCMEM_PSGSC_CTL_MACRO1_MODE(region->macro_state[1]) |
 			OCMEM_PSGSC_CTL_MACRO2_MODE(region->macro_state[2]) |
 			OCMEM_PSGSC_CTL_MACRO3_MODE(region->macro_state[3]);

 		ocmem_write(ocmem, OCMEM_REG_PSGSC_CTL(i), data);
 	}
 }

 static unsigned long phys_to_offset(struct ocmem *ocmem,
 				    unsigned long addr)
 {
 	if (addr < ocmem->memory->start || addr >= ocmem->memory->end)
 		return 0;

 	return addr - ocmem->memory->start;
 }

 static unsigned long device_address(struct ocmem *ocmem,
 				    enum ocmem_client client,
 				    unsigned long addr)
 {
 	WARN_ON(client != OCMEM_GRAPHICS);

 	/* TODO: gpu uses phys_to_offset, but others do not.. */
 	return phys_to_offset(ocmem, addr);
 }

 static void update_range(struct ocmem *ocmem, struct ocmem_buf *buf,
 			 enum ocmem_macro_state mstate, enum region_mode rmode)
 {
 	unsigned long offset = 0;
 	int i, j;

 	for (i = 0; i < ocmem->config->num_regions; i++) {
 		struct ocmem_region *region = &ocmem->regions[i];

 		if (buf->offset <= offset && offset < buf->offset + buf->len)
 			region->mode = rmode;

 		for (j = 0; j < region->num_macros; j++) {
 			if (buf->offset <= offset &&
 			    offset < buf->offset + buf->len)
 				region->macro_state[j] = mstate;

 			offset += region->macro_size;
 		}
 	}

 	update_ocmem(ocmem);
 }

 struct ocmem *of_get_ocmem(struct device *dev)
 {
 	struct platform_device *pdev;
 	struct ocmem *ocmem;

 	struct device_node *devnode __free(device_node) = of_parse_phandle(dev->of_node,
 									   "sram", 0);
 	if (!devnode || !devnode->parent) {
 		dev_err(dev, "Cannot look up sram phandle\n");
 		return ERR_PTR(-ENODEV);
 	}

 	pdev = of_find_device_by_node(devnode->parent);
 	if (!pdev) {
 		dev_err(dev, "Cannot find device node %s\n", devnode->name);
 		return ERR_PTR(-EPROBE_DEFER);
 	}

 	ocmem = platform_get_drvdata(pdev);
 	if (!ocmem) {
 		dev_err(dev, "Cannot get ocmem\n");
 		put_device(&pdev->dev);
 		return ERR_PTR(-ENODEV);
 	}
 	return ocmem;
 }
 EXPORT_SYMBOL_GPL(of_get_ocmem);

 struct ocmem_buf *ocmem_allocate(struct ocmem *ocmem, enum ocmem_client client,
 				 unsigned long size)
 {
 	int ret;

 	/* TODO: add support for other clients... */
 	if (WARN_ON(client != OCMEM_GRAPHICS))
 		return ERR_PTR(-ENODEV);

 	if (size < OCMEM_MIN_ALLOC || !IS_ALIGNED(size, OCMEM_MIN_ALIGN))
 		return ERR_PTR(-EINVAL);

 	if (test_and_set_bit_lock(BIT(client), &ocmem->active_allocations))
 		return ERR_PTR(-EBUSY);

 	struct ocmem_buf *buf __free(kfree) = kzalloc(sizeof(*buf), GFP_KERNEL);
 	if (!buf) {
 		ret = -ENOMEM;
 		goto err_unlock;
 	}

 	buf->offset = 0;
 	buf->addr = device_address(ocmem, client, buf->offset);
 	buf->len = size;

 	update_range(ocmem, buf, CORE_ON, WIDE_MODE);

 	if (qcom_scm_ocmem_lock_available()) {
 		ret = qcom_scm_ocmem_lock(QCOM_SCM_OCMEM_GRAPHICS_ID,
 					  buf->offset, buf->len, WIDE_MODE);
 		if (ret) {
 			dev_err(ocmem->dev, "could not lock: %d\n", ret);
 			ret = -EINVAL;
 			goto err_unlock;
 		}
 	} else {
 		ocmem_write(ocmem, OCMEM_REG_GFX_MPU_START, buf->offset);
 		ocmem_write(ocmem, OCMEM_REG_GFX_MPU_END,
 			    buf->offset + buf->len);
 	}

 	dev_dbg(ocmem->dev, "using %ldK of OCMEM at 0x%08lx for client %d\n",
 		size / 1024, buf->addr, client);

 	return_ptr(buf);

 err_unlock:
 	clear_bit_unlock(BIT(client), &ocmem->active_allocations);

 	return ERR_PTR(ret);
 }
 EXPORT_SYMBOL_GPL(ocmem_allocate);

 void ocmem_free(struct ocmem *ocmem, enum ocmem_client client,
 		struct ocmem_buf *buf)
 {
 	/* TODO: add support for other clients... */
 	if (WARN_ON(client != OCMEM_GRAPHICS))
 		return;

 	update_range(ocmem, buf, CLK_OFF, MODE_DEFAULT);

 	if (qcom_scm_ocmem_lock_available()) {
 		int ret;

 		ret = qcom_scm_ocmem_unlock(QCOM_SCM_OCMEM_GRAPHICS_ID,
 					    buf->offset, buf->len);
 		if (ret)
 			dev_err(ocmem->dev, "could not unlock: %d\n", ret);
 	} else {
 		ocmem_write(ocmem, OCMEM_REG_GFX_MPU_START, 0x0);
 		ocmem_write(ocmem, OCMEM_REG_GFX_MPU_END, 0x0);
 	}

 	kfree(buf);

 	clear_bit_unlock(BIT(client), &ocmem->active_allocations);
 }
 EXPORT_SYMBOL_GPL(ocmem_free);

 static int ocmem_dev_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	unsigned long reg, region_size;
 	int i, j, ret, num_banks;
 	struct ocmem *ocmem;

 	if (!qcom_scm_is_available())
 		return -EPROBE_DEFER;

 	ocmem = devm_kzalloc(dev, sizeof(*ocmem), GFP_KERNEL);
 	if (!ocmem)
 		return -ENOMEM;

 	ocmem->dev = dev;
 	ocmem->config = device_get_match_data(dev);

 	ocmem->core_clk = devm_clk_get(dev, "core");
 	if (IS_ERR(ocmem->core_clk))
 		return dev_err_probe(dev, PTR_ERR(ocmem->core_clk),
 				     "Unable to get core clock\n");

 	ocmem->iface_clk = devm_clk_get_optional(dev, "iface");
 	if (IS_ERR(ocmem->iface_clk))
 		return dev_err_probe(dev, PTR_ERR(ocmem->iface_clk),
 				     "Unable to get iface clock\n");

 	ocmem->mmio = devm_platform_ioremap_resource_byname(pdev, "ctrl");
 	if (IS_ERR(ocmem->mmio))
 		return dev_err_probe(&pdev->dev, PTR_ERR(ocmem->mmio),
 				     "Failed to ioremap ocmem_ctrl resource\n");

 	ocmem->memory = platform_get_resource_byname(pdev, IORESOURCE_MEM,
 						     "mem");
 	if (!ocmem->memory) {
 		dev_err(dev, "Could not get mem region\n");
 		return -ENXIO;
 	}

 	/* The core clock is synchronous with graphics */
 	WARN_ON(clk_set_rate(ocmem->core_clk, 1000) < 0);

 	ret = clk_prepare_enable(ocmem->core_clk);
 	if (ret)
 		return dev_err_probe(ocmem->dev, ret, "Failed to enable core clock\n");

 	ret = clk_prepare_enable(ocmem->iface_clk);
 	if (ret) {
 		clk_disable_unprepare(ocmem->core_clk);
 		return dev_err_probe(ocmem->dev, ret, "Failed to enable iface clock\n");
 	}

 	if (qcom_scm_restore_sec_cfg_available()) {
 		dev_dbg(dev, "configuring scm\n");
 		ret = qcom_scm_restore_sec_cfg(QCOM_SCM_OCMEM_DEV_ID, 0);
 		if (ret) {
 			dev_err_probe(dev, ret, "Could not enable secure configuration\n");
 			goto err_clk_disable;
 		}
 	}

 	reg = ocmem_read(ocmem, OCMEM_REG_HW_VERSION);
 	dev_dbg(dev, "OCMEM hardware version: %lu.%lu.%lu\n",
 		OCMEM_HW_VERSION_MAJOR(reg),
 		OCMEM_HW_VERSION_MINOR(reg),
 		OCMEM_HW_VERSION_STEP(reg));

 	reg = ocmem_read(ocmem, OCMEM_REG_HW_PROFILE);
 	ocmem->num_ports = OCMEM_HW_PROFILE_NUM_PORTS(reg);
 	ocmem->num_macros = OCMEM_HW_PROFILE_NUM_MACROS(reg);
 	ocmem->interleaved = !!(reg & OCMEM_HW_PROFILE_INTERLEAVING);

 	num_banks = ocmem->num_ports / 2;
 	region_size = ocmem->config->macro_size * num_banks;

 	dev_info(dev, "%u ports, %u regions, %u macros, %sinterleaved\n",
 		 ocmem->num_ports, ocmem->config->num_regions,
 		 ocmem->num_macros, ocmem->interleaved ? "" : "not ");

 	ocmem->regions = devm_kcalloc(dev, ocmem->config->num_regions,
 				      sizeof(struct ocmem_region), GFP_KERNEL);
 	if (!ocmem->regions) {
 		ret = -ENOMEM;
 		goto err_clk_disable;
 	}

 	for (i = 0; i < ocmem->config->num_regions; i++) {
 		struct ocmem_region *region = &ocmem->regions[i];

 		if (WARN_ON(num_banks > ARRAY_SIZE(region->macro_state))) {
 			ret = -EINVAL;
 			goto err_clk_disable;
 		}

 		region->mode = MODE_DEFAULT;
 		region->num_macros = num_banks;

 		if (i == (ocmem->config->num_regions - 1) &&
 		    reg & OCMEM_HW_PROFILE_LAST_REGN_HALFSIZE) {
 			region->macro_size = ocmem->config->macro_size / 2;
 			region->region_size = region_size / 2;
 		} else {
 			region->macro_size = ocmem->config->macro_size;
 			region->region_size = region_size;
 		}

 		for (j = 0; j < ARRAY_SIZE(region->macro_state); j++)
 			region->macro_state[j] = CLK_OFF;
 	}

 	platform_set_drvdata(pdev, ocmem);

 	return 0;

 err_clk_disable:
 	clk_disable_unprepare(ocmem->core_clk);
 	clk_disable_unprepare(ocmem->iface_clk);
 	return ret;
 }

 static void ocmem_dev_remove(struct platform_device *pdev)
 {
 	struct ocmem *ocmem = platform_get_drvdata(pdev);

 	clk_disable_unprepare(ocmem->core_clk);
 	clk_disable_unprepare(ocmem->iface_clk);
 }

 static const struct ocmem_config ocmem_8226_config = {
 	.num_regions = 1,
 	.macro_size = SZ_128K,
 };

 static const struct ocmem_config ocmem_8974_config = {
 	.num_regions = 3,
 	.macro_size = SZ_128K,
 };

 static const struct of_device_id ocmem_of_match[] = {
 	{ .compatible = "qcom,msm8226-ocmem", .data = &ocmem_8226_config },
 	{ .compatible = "qcom,msm8974-ocmem", .data = &ocmem_8974_config },
 	{ }
 };

 MODULE_DEVICE_TABLE(of, ocmem_of_match);

 static struct platform_driver ocmem_driver = {
 	.probe = ocmem_dev_probe,
 	.remove_new = ocmem_dev_remove,
 	.driver = {
 		.name = "ocmem",
 		.of_match_table = ocmem_of_match,
 	},
 };

 module_platform_driver(ocmem_driver);

 MODULE_DESCRIPTION("On Chip Memory (OCMEM) allocator for some Snapdragon SoCs");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* The On Chip Memory (OCMEM) allocator allows various clients to allocate
	* memory from OCMEM based on performance, latency and power requirements.
	* This is typically used by the GPU, camera/video, and audio components on
	* some Snapdragon SoCs.
	*
	* Copyright (C) 2019 Brian Masney <masneyb@onstation.org>
	* Copyright (C) 2015 Red Hat. Author: Rob Clark <robdclark@gmail.com>
	*/

	#include <linux/bitfield.h>
	#include <linux/cleanup.h>
	#include <linux/clk.h>
	#include <linux/io.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/of_platform.h>
	#include <linux/platform_device.h>
	#include <linux/firmware/qcom/qcom_scm.h>
	#include <linux/sizes.h>
	#include <linux/slab.h>
	#include <linux/types.h>
	#include <soc/qcom/ocmem.h>

	enum region_mode {
	WIDE_MODE = 0x0,
	THIN_MODE,
	MODE_DEFAULT = WIDE_MODE,
	};

	enum ocmem_macro_state {
	PASSTHROUGH = 0,
	PERI_ON = 1,
	CORE_ON = 2,
	CLK_OFF = 4,
	};

	struct ocmem_region {
	bool interleaved;
	enum region_mode mode;
	unsigned int num_macros;
	enum ocmem_macro_state macro_state[4];
	unsigned long macro_size;
	unsigned long region_size;
	};

	struct ocmem_config {
	uint8_t num_regions;
	unsigned long macro_size;
	};

	struct ocmem {
	struct device *dev;
	const struct ocmem_config *config;
	struct resource *memory;
	void __iomem *mmio;
	struct clk *core_clk;
	struct clk *iface_clk;
	unsigned int num_ports;
	unsigned int num_macros;
	bool interleaved;
	struct ocmem_region *regions;
	unsigned long active_allocations;
	};

	#define OCMEM_MIN_ALIGN SZ_64K
	#define OCMEM_MIN_ALLOC SZ_64K

	#define OCMEM_REG_HW_VERSION 0x00000000
	#define OCMEM_REG_HW_PROFILE 0x00000004

	#define OCMEM_REG_REGION_MODE_CTL 0x00001000
	#define OCMEM_REGION_MODE_CTL_REG0_THIN 0x00000001
	#define OCMEM_REGION_MODE_CTL_REG1_THIN 0x00000002
	#define OCMEM_REGION_MODE_CTL_REG2_THIN 0x00000004
	#define OCMEM_REGION_MODE_CTL_REG3_THIN 0x00000008

	#define OCMEM_REG_GFX_MPU_START 0x00001004
	#define OCMEM_REG_GFX_MPU_END 0x00001008

	#define OCMEM_HW_VERSION_MAJOR(val) FIELD_GET(GENMASK(31, 28), val)
	#define OCMEM_HW_VERSION_MINOR(val) FIELD_GET(GENMASK(27, 16), val)
	#define OCMEM_HW_VERSION_STEP(val) FIELD_GET(GENMASK(15, 0), val)

	#define OCMEM_HW_PROFILE_NUM_PORTS(val) FIELD_GET(0x0000000f, (val))
	#define OCMEM_HW_PROFILE_NUM_MACROS(val) FIELD_GET(0x00003f00, (val))

	#define OCMEM_HW_PROFILE_LAST_REGN_HALFSIZE 0x00010000
	#define OCMEM_HW_PROFILE_INTERLEAVING 0x00020000
	#define OCMEM_REG_GEN_STATUS 0x0000000c

	#define OCMEM_REG_PSGSC_STATUS 0x00000038
	#define OCMEM_REG_PSGSC_CTL(i0) (0x0000003c + 0x1*(i0))

	#define OCMEM_PSGSC_CTL_MACRO0_MODE(val) FIELD_PREP(0x00000007, (val))
	#define OCMEM_PSGSC_CTL_MACRO1_MODE(val) FIELD_PREP(0x00000070, (val))
	#define OCMEM_PSGSC_CTL_MACRO2_MODE(val) FIELD_PREP(0x00000700, (val))
	#define OCMEM_PSGSC_CTL_MACRO3_MODE(val) FIELD_PREP(0x00007000, (val))

	static inline void ocmem_write(struct ocmem *ocmem, u32 reg, u32 data)
	{
	writel(data, ocmem->mmio + reg);
	}

	static inline u32 ocmem_read(struct ocmem *ocmem, u32 reg)
	{
	return readl(ocmem->mmio + reg);
	}

	static void update_ocmem(struct ocmem *ocmem)
	{
	uint32_t region_mode_ctrl = 0x0;
	int i;

	if (!qcom_scm_ocmem_lock_available()) {
	for (i = 0; i < ocmem->config->num_regions; i++) {
	struct ocmem_region *region = &ocmem->regions[i];

	if (region->mode == THIN_MODE)
	region_mode_ctrl \|= BIT(i);
	}

	dev_dbg(ocmem->dev, "ocmem_region_mode_control %x\n",
	region_mode_ctrl);
	ocmem_write(ocmem, OCMEM_REG_REGION_MODE_CTL, region_mode_ctrl);
	}

	for (i = 0; i < ocmem->config->num_regions; i++) {
	struct ocmem_region *region = &ocmem->regions[i];
	u32 data;

	data = OCMEM_PSGSC_CTL_MACRO0_MODE(region->macro_state[0]) \|
	OCMEM_PSGSC_CTL_MACRO1_MODE(region->macro_state[1]) \|
	OCMEM_PSGSC_CTL_MACRO2_MODE(region->macro_state[2]) \|
	OCMEM_PSGSC_CTL_MACRO3_MODE(region->macro_state[3]);

	ocmem_write(ocmem, OCMEM_REG_PSGSC_CTL(i), data);
	}
	}

	static unsigned long phys_to_offset(struct ocmem *ocmem,
	unsigned long addr)
	{
	if (addr < ocmem->memory->start \|\| addr >= ocmem->memory->end)
	return 0;

	return addr - ocmem->memory->start;
	}

	static unsigned long device_address(struct ocmem *ocmem,
	enum ocmem_client client,
	unsigned long addr)
	{
	WARN_ON(client != OCMEM_GRAPHICS);

	/* TODO: gpu uses phys_to_offset, but others do not.. */
	return phys_to_offset(ocmem, addr);
	}

	static void update_range(struct ocmem ocmem, struct ocmem_buf buf,
	enum ocmem_macro_state mstate, enum region_mode rmode)
	{
	unsigned long offset = 0;
	int i, j;

	for (i = 0; i < ocmem->config->num_regions; i++) {
	struct ocmem_region *region = &ocmem->regions[i];

	if (buf->offset <= offset && offset < buf->offset + buf->len)
	region->mode = rmode;

	for (j = 0; j < region->num_macros; j++) {
	if (buf->offset <= offset &&
	offset < buf->offset + buf->len)
	region->macro_state[j] = mstate;

	offset += region->macro_size;
	}
	}

	update_ocmem(ocmem);
	}

	struct ocmem of_get_ocmem(struct device dev)
	{
	struct platform_device *pdev;
	struct ocmem *ocmem;

	struct device_node *devnode __free(device_node) = of_parse_phandle(dev->of_node,
	"sram", 0);
	if (!devnode \|\| !devnode->parent) {
	dev_err(dev, "Cannot look up sram phandle\n");
	return ERR_PTR(-ENODEV);
	}

	pdev = of_find_device_by_node(devnode->parent);
	if (!pdev) {
	dev_err(dev, "Cannot find device node %s\n", devnode->name);
	return ERR_PTR(-EPROBE_DEFER);
	}

	ocmem = platform_get_drvdata(pdev);
	if (!ocmem) {
	dev_err(dev, "Cannot get ocmem\n");
	put_device(&pdev->dev);
	return ERR_PTR(-ENODEV);
	}
	return ocmem;
	}
	EXPORT_SYMBOL_GPL(of_get_ocmem);

	struct ocmem_buf ocmem_allocate(struct ocmem ocmem, enum ocmem_client client,
	unsigned long size)
	{
	int ret;

	/* TODO: add support for other clients... */
	if (WARN_ON(client != OCMEM_GRAPHICS))
	return ERR_PTR(-ENODEV);

	if (size < OCMEM_MIN_ALLOC \|\| !IS_ALIGNED(size, OCMEM_MIN_ALIGN))
	return ERR_PTR(-EINVAL);

	if (test_and_set_bit_lock(BIT(client), &ocmem->active_allocations))
	return ERR_PTR(-EBUSY);

	struct ocmem_buf buf __free(kfree) = kzalloc(sizeof(buf), GFP_KERNEL);
	if (!buf) {
	ret = -ENOMEM;
	goto err_unlock;
	}

	buf->offset = 0;
	buf->addr = device_address(ocmem, client, buf->offset);
	buf->len = size;

	update_range(ocmem, buf, CORE_ON, WIDE_MODE);

	if (qcom_scm_ocmem_lock_available()) {
	ret = qcom_scm_ocmem_lock(QCOM_SCM_OCMEM_GRAPHICS_ID,
	buf->offset, buf->len, WIDE_MODE);
	if (ret) {
	dev_err(ocmem->dev, "could not lock: %d\n", ret);
	ret = -EINVAL;
	goto err_unlock;
	}
	} else {
	ocmem_write(ocmem, OCMEM_REG_GFX_MPU_START, buf->offset);
	ocmem_write(ocmem, OCMEM_REG_GFX_MPU_END,
	buf->offset + buf->len);
	}

	dev_dbg(ocmem->dev, "using %ldK of OCMEM at 0x%08lx for client %d\n",
	size / 1024, buf->addr, client);

	return_ptr(buf);

	err_unlock:
	clear_bit_unlock(BIT(client), &ocmem->active_allocations);

	return ERR_PTR(ret);
	}
	EXPORT_SYMBOL_GPL(ocmem_allocate);

	void ocmem_free(struct ocmem *ocmem, enum ocmem_client client,
	struct ocmem_buf *buf)
	{
	/* TODO: add support for other clients... */
	if (WARN_ON(client != OCMEM_GRAPHICS))
	return;

	update_range(ocmem, buf, CLK_OFF, MODE_DEFAULT);

	if (qcom_scm_ocmem_lock_available()) {
	int ret;

	ret = qcom_scm_ocmem_unlock(QCOM_SCM_OCMEM_GRAPHICS_ID,
	buf->offset, buf->len);
	if (ret)
	dev_err(ocmem->dev, "could not unlock: %d\n", ret);
	} else {
	ocmem_write(ocmem, OCMEM_REG_GFX_MPU_START, 0x0);
	ocmem_write(ocmem, OCMEM_REG_GFX_MPU_END, 0x0);
	}

	kfree(buf);

	clear_bit_unlock(BIT(client), &ocmem->active_allocations);
	}
	EXPORT_SYMBOL_GPL(ocmem_free);

	static int ocmem_dev_probe(struct platform_device *pdev)
	{
	struct device *dev = &pdev->dev;
	unsigned long reg, region_size;
	int i, j, ret, num_banks;
	struct ocmem *ocmem;

	if (!qcom_scm_is_available())
	return -EPROBE_DEFER;

	ocmem = devm_kzalloc(dev, sizeof(*ocmem), GFP_KERNEL);
	if (!ocmem)
	return -ENOMEM;

	ocmem->dev = dev;
	ocmem->config = device_get_match_data(dev);

	ocmem->core_clk = devm_clk_get(dev, "core");
	if (IS_ERR(ocmem->core_clk))
	return dev_err_probe(dev, PTR_ERR(ocmem->core_clk),
	"Unable to get core clock\n");

	ocmem->iface_clk = devm_clk_get_optional(dev, "iface");
	if (IS_ERR(ocmem->iface_clk))
	return dev_err_probe(dev, PTR_ERR(ocmem->iface_clk),
	"Unable to get iface clock\n");

	ocmem->mmio = devm_platform_ioremap_resource_byname(pdev, "ctrl");
	if (IS_ERR(ocmem->mmio))
	return dev_err_probe(&pdev->dev, PTR_ERR(ocmem->mmio),
	"Failed to ioremap ocmem_ctrl resource\n");

	ocmem->memory = platform_get_resource_byname(pdev, IORESOURCE_MEM,
	"mem");
	if (!ocmem->memory) {
	dev_err(dev, "Could not get mem region\n");
	return -ENXIO;
	}

	/* The core clock is synchronous with graphics */
	WARN_ON(clk_set_rate(ocmem->core_clk, 1000) < 0);

	ret = clk_prepare_enable(ocmem->core_clk);
	if (ret)
	return dev_err_probe(ocmem->dev, ret, "Failed to enable core clock\n");

	ret = clk_prepare_enable(ocmem->iface_clk);
	if (ret) {
	clk_disable_unprepare(ocmem->core_clk);
	return dev_err_probe(ocmem->dev, ret, "Failed to enable iface clock\n");
	}

	if (qcom_scm_restore_sec_cfg_available()) {
	dev_dbg(dev, "configuring scm\n");
	ret = qcom_scm_restore_sec_cfg(QCOM_SCM_OCMEM_DEV_ID, 0);
	if (ret) {
	dev_err_probe(dev, ret, "Could not enable secure configuration\n");
	goto err_clk_disable;
	}
	}

	reg = ocmem_read(ocmem, OCMEM_REG_HW_VERSION);
	dev_dbg(dev, "OCMEM hardware version: %lu.%lu.%lu\n",
	OCMEM_HW_VERSION_MAJOR(reg),
	OCMEM_HW_VERSION_MINOR(reg),
	OCMEM_HW_VERSION_STEP(reg));

	reg = ocmem_read(ocmem, OCMEM_REG_HW_PROFILE);
	ocmem->num_ports = OCMEM_HW_PROFILE_NUM_PORTS(reg);
	ocmem->num_macros = OCMEM_HW_PROFILE_NUM_MACROS(reg);
	ocmem->interleaved = !!(reg & OCMEM_HW_PROFILE_INTERLEAVING);

	num_banks = ocmem->num_ports / 2;
	region_size = ocmem->config->macro_size * num_banks;

	dev_info(dev, "%u ports, %u regions, %u macros, %sinterleaved\n",
	ocmem->num_ports, ocmem->config->num_regions,
	ocmem->num_macros, ocmem->interleaved ? "" : "not ");

	ocmem->regions = devm_kcalloc(dev, ocmem->config->num_regions,
	sizeof(struct ocmem_region), GFP_KERNEL);
	if (!ocmem->regions) {
	ret = -ENOMEM;
	goto err_clk_disable;
	}

	for (i = 0; i < ocmem->config->num_regions; i++) {
	struct ocmem_region *region = &ocmem->regions[i];

	if (WARN_ON(num_banks > ARRAY_SIZE(region->macro_state))) {
	ret = -EINVAL;
	goto err_clk_disable;
	}

	region->mode = MODE_DEFAULT;
	region->num_macros = num_banks;

	if (i == (ocmem->config->num_regions - 1) &&
	reg & OCMEM_HW_PROFILE_LAST_REGN_HALFSIZE) {
	region->macro_size = ocmem->config->macro_size / 2;
	region->region_size = region_size / 2;
	} else {
	region->macro_size = ocmem->config->macro_size;
	region->region_size = region_size;
	}

	for (j = 0; j < ARRAY_SIZE(region->macro_state); j++)
	region->macro_state[j] = CLK_OFF;
	}

	platform_set_drvdata(pdev, ocmem);

	return 0;

	err_clk_disable:
	clk_disable_unprepare(ocmem->core_clk);
	clk_disable_unprepare(ocmem->iface_clk);
	return ret;
	}

	static void ocmem_dev_remove(struct platform_device *pdev)
	{
	struct ocmem *ocmem = platform_get_drvdata(pdev);

	clk_disable_unprepare(ocmem->core_clk);
	clk_disable_unprepare(ocmem->iface_clk);
	}

	static const struct ocmem_config ocmem_8226_config = {
	.num_regions = 1,
	.macro_size = SZ_128K,
	};

	static const struct ocmem_config ocmem_8974_config = {
	.num_regions = 3,
	.macro_size = SZ_128K,
	};

	static const struct of_device_id ocmem_of_match[] = {
	{ .compatible = "qcom,msm8226-ocmem", .data = &ocmem_8226_config },
	{ .compatible = "qcom,msm8974-ocmem", .data = &ocmem_8974_config },
	{ }
	};

	MODULE_DEVICE_TABLE(of, ocmem_of_match);

	static struct platform_driver ocmem_driver = {
	.probe = ocmem_dev_probe,
	.remove_new = ocmem_dev_remove,
	.driver = {
	.name = "ocmem",
	.of_match_table = ocmem_of_match,
	},
	};

	module_platform_driver(ocmem_driver);

	MODULE_DESCRIPTION("On Chip Memory (OCMEM) allocator for some Snapdragon SoCs");
	MODULE_LICENSE("GPL v2");