// 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/clk.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/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;
	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_PROFILE_NUM_PORTS(val)		FIELD_PREP(0x0000000f, (val))
#define OCMEM_HW_PROFILE_NUM_MACROS(val)	FIELD_PREP(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))

#define OCMEM_CLK_CORE_IDX			0
static struct clk_bulk_data ocmem_clks[] = {
	{
		.id = "core",
	},
	{
		.id = "iface",
	},
};

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 device_node *devnode;
	struct ocmem *ocmem;

	devnode = 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");
		return ERR_PTR(-ENODEV);
	}
	return ocmem;
}
EXPORT_SYMBOL(of_get_ocmem);

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

	buf = 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_kfree;
		}
	} 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 buf;

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

	return ERR_PTR(ret);
}
EXPORT_SYMBOL(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(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 resource *res;
	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);

	ret = devm_clk_bulk_get(dev, ARRAY_SIZE(ocmem_clks), ocmem_clks);
	if (ret) {
		if (ret != -EPROBE_DEFER)
			dev_err(dev, "Unable to get clocks\n");

		return ret;
	}

	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "ctrl");
	ocmem->mmio = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(ocmem->mmio)) {
		dev_err(&pdev->dev, "Failed to ioremap ocmem_ctrl resource\n");
		return PTR_ERR(ocmem->mmio);
	}

	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_clks[OCMEM_CLK_CORE_IDX].clk, 1000) < 0);

	ret = clk_bulk_prepare_enable(ARRAY_SIZE(ocmem_clks), ocmem_clks);
	if (ret) {
		dev_info(ocmem->dev, "Failed to enable clocks\n");
		return ret;
	}

	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(dev, "Could not enable secure configuration\n");
			goto err_clk_disable;
		}
	}

	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_bulk_disable_unprepare(ARRAY_SIZE(ocmem_clks), ocmem_clks);
	return ret;
}

static int ocmem_dev_remove(struct platform_device *pdev)
{
	clk_bulk_disable_unprepare(ARRAY_SIZE(ocmem_clks), ocmem_clks);

	return 0;
}

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,msm8974-ocmem", .data = &ocmem_8974_config },
	{ }
};

MODULE_DEVICE_TABLE(of, ocmem_of_match);

static struct platform_driver ocmem_driver = {
	.probe = ocmem_dev_probe,
	.remove = 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");