// SPDX-License-Identifier: GPL-2.0
//
// Copyright (c) 2019 MediaTek Inc.

#include <asm/barrier.h>
#include <linux/clk.h>
#include <linux/dma-mapping.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/of_platform.h>
#include <linux/of_reserved_mem.h>
#include <linux/platform_device.h>
#include <linux/remoteproc.h>
#include <linux/remoteproc/mtk_scp.h>
#include <linux/rpmsg/mtk_rpmsg.h>

#include "mtk_common.h"
#include "remoteproc_internal.h"

#define MAX_CODE_SIZE 0x500000
#define SCP_FW_END 0x7C000

/**
 * scp_get() - get a reference to SCP.
 *
 * @pdev:	the platform device of the module requesting SCP platform
 *		device for using SCP API.
 *
 * Return: Return NULL if failed.  otherwise reference to SCP.
 **/
struct mtk_scp *scp_get(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct device_node *scp_node;
	struct platform_device *scp_pdev;

	scp_node = of_parse_phandle(dev->of_node, "mediatek,scp", 0);
	if (!scp_node) {
		dev_err(dev, "can't get SCP node\n");
		return NULL;
	}

	scp_pdev = of_find_device_by_node(scp_node);
	of_node_put(scp_node);

	if (WARN_ON(!scp_pdev)) {
		dev_err(dev, "SCP pdev failed\n");
		return NULL;
	}

	return platform_get_drvdata(scp_pdev);
}
EXPORT_SYMBOL_GPL(scp_get);

/**
 * scp_put() - "free" the SCP
 *
 * @scp:	mtk_scp structure from scp_get().
 **/
void scp_put(struct mtk_scp *scp)
{
	put_device(scp->dev);
}
EXPORT_SYMBOL_GPL(scp_put);

static void scp_wdt_handler(struct mtk_scp *scp, u32 scp_to_host)
{
	dev_err(scp->dev, "SCP watchdog timeout! 0x%x", scp_to_host);
	rproc_report_crash(scp->rproc, RPROC_WATCHDOG);
}

static void scp_init_ipi_handler(void *data, unsigned int len, void *priv)
{
	struct mtk_scp *scp = (struct mtk_scp *)priv;
	struct scp_run *run = (struct scp_run *)data;

	scp->run.signaled = run->signaled;
	strscpy(scp->run.fw_ver, run->fw_ver, SCP_FW_VER_LEN);
	scp->run.dec_capability = run->dec_capability;
	scp->run.enc_capability = run->enc_capability;
	wake_up_interruptible(&scp->run.wq);
}

static void scp_ipi_handler(struct mtk_scp *scp)
{
	struct mtk_share_obj __iomem *rcv_obj = scp->recv_buf;
	struct scp_ipi_desc *ipi_desc = scp->ipi_desc;
	u8 tmp_data[SCP_SHARE_BUFFER_SIZE];
	scp_ipi_handler_t handler;
	u32 id = readl(&rcv_obj->id);
	u32 len = readl(&rcv_obj->len);

	if (len > SCP_SHARE_BUFFER_SIZE) {
		dev_err(scp->dev, "ipi message too long (len %d, max %d)", len,
			SCP_SHARE_BUFFER_SIZE);
		return;
	}
	if (id >= SCP_IPI_MAX) {
		dev_err(scp->dev, "No such ipi id = %d\n", id);
		return;
	}

	scp_ipi_lock(scp, id);
	handler = ipi_desc[id].handler;
	if (!handler) {
		dev_err(scp->dev, "No such ipi id = %d\n", id);
		scp_ipi_unlock(scp, id);
		return;
	}

	memcpy_fromio(tmp_data, &rcv_obj->share_buf, len);
	handler(tmp_data, len, ipi_desc[id].priv);
	scp_ipi_unlock(scp, id);

	scp->ipi_id_ack[id] = true;
	wake_up(&scp->ack_wq);
}

static int scp_ipi_init(struct mtk_scp *scp)
{
	size_t send_offset = SCP_FW_END - sizeof(struct mtk_share_obj);
	size_t recv_offset = send_offset - sizeof(struct mtk_share_obj);

	/* Disable SCP to host interrupt */
	writel(MT8183_SCP_IPC_INT_BIT, scp->reg_base + MT8183_SCP_TO_HOST);

	/* shared buffer initialization */
	scp->recv_buf =
		(struct mtk_share_obj __iomem *)(scp->sram_base + recv_offset);
	scp->send_buf =
		(struct mtk_share_obj __iomem *)(scp->sram_base + send_offset);
	memset_io(scp->recv_buf, 0, sizeof(scp->recv_buf));
	memset_io(scp->send_buf, 0, sizeof(scp->send_buf));

	return 0;
}

static void scp_reset_assert(const struct mtk_scp *scp)
{
	u32 val;

	val = readl(scp->reg_base + MT8183_SW_RSTN);
	val &= ~MT8183_SW_RSTN_BIT;
	writel(val, scp->reg_base + MT8183_SW_RSTN);
}

static void scp_reset_deassert(const struct mtk_scp *scp)
{
	u32 val;

	val = readl(scp->reg_base + MT8183_SW_RSTN);
	val |= MT8183_SW_RSTN_BIT;
	writel(val, scp->reg_base + MT8183_SW_RSTN);
}

static irqreturn_t scp_irq_handler(int irq, void *priv)
{
	struct mtk_scp *scp = priv;
	u32 scp_to_host;
	int ret;

	ret = clk_prepare_enable(scp->clk);
	if (ret) {
		dev_err(scp->dev, "failed to enable clocks\n");
		return IRQ_NONE;
	}

	scp_to_host = readl(scp->reg_base + MT8183_SCP_TO_HOST);
	if (scp_to_host & MT8183_SCP_IPC_INT_BIT)
		scp_ipi_handler(scp);
	else
		scp_wdt_handler(scp, scp_to_host);

	/* SCP won't send another interrupt until we set SCP_TO_HOST to 0. */
	writel(MT8183_SCP_IPC_INT_BIT | MT8183_SCP_WDT_INT_BIT,
	       scp->reg_base + MT8183_SCP_TO_HOST);
	clk_disable_unprepare(scp->clk);

	return IRQ_HANDLED;
}

static int scp_elf_load_segments(struct rproc *rproc, const struct firmware *fw)
{
	struct device *dev = &rproc->dev;
	struct elf32_hdr *ehdr;
	struct elf32_phdr *phdr;
	int i, ret = 0;
	const u8 *elf_data = fw->data;

	ehdr = (struct elf32_hdr *)elf_data;
	phdr = (struct elf32_phdr *)(elf_data + ehdr->e_phoff);

	/* go through the available ELF segments */
	for (i = 0; i < ehdr->e_phnum; i++, phdr++) {
		u32 da = phdr->p_paddr;
		u32 memsz = phdr->p_memsz;
		u32 filesz = phdr->p_filesz;
		u32 offset = phdr->p_offset;
		void __iomem *ptr;

		if (phdr->p_type != PT_LOAD)
			continue;

		dev_dbg(dev, "phdr: type %d da 0x%x memsz 0x%x filesz 0x%x\n",
			phdr->p_type, da, memsz, filesz);

		if (filesz > memsz) {
			dev_err(dev, "bad phdr filesz 0x%x memsz 0x%x\n",
				filesz, memsz);
			ret = -EINVAL;
			break;
		}

		if (offset + filesz > fw->size) {
			dev_err(dev, "truncated fw: need 0x%x avail 0x%zx\n",
				offset + filesz, fw->size);
			ret = -EINVAL;
			break;
		}

		/* grab the kernel address for this device address */
		ptr = (void __iomem *)rproc_da_to_va(rproc, da, memsz);
		if (!ptr) {
			dev_err(dev, "bad phdr da 0x%x mem 0x%x\n", da, memsz);
			ret = -EINVAL;
			break;
		}

		/* put the segment where the remote processor expects it */
		if (phdr->p_filesz)
			scp_memcpy_aligned(ptr, elf_data + phdr->p_offset,
					   filesz);
	}

	return ret;
}

static int scp_load(struct rproc *rproc, const struct firmware *fw)
{
	const struct mtk_scp *scp = rproc->priv;
	struct device *dev = scp->dev;
	int ret;

	ret = clk_prepare_enable(scp->clk);
	if (ret) {
		dev_err(dev, "failed to enable clocks\n");
		return ret;
	}

	/* Hold SCP in reset while loading FW. */
	scp_reset_assert(scp);

	/* Reset clocks before loading FW */
	writel(0x0, scp->reg_base + MT8183_SCP_CLK_SW_SEL);
	writel(0x0, scp->reg_base + MT8183_SCP_CLK_DIV_SEL);

	/* Initialize TCM before loading FW. */
	writel(0x0, scp->reg_base + MT8183_SCP_L1_SRAM_PD);
	writel(0x0, scp->reg_base + MT8183_SCP_TCM_TAIL_SRAM_PD);

	/* Turn on the power of SCP's SRAM before using it. */
	writel(0x0, scp->reg_base + MT8183_SCP_SRAM_PDN);

	/*
	 * Set I-cache and D-cache size before loading SCP FW.
	 * SCP SRAM logical address may change when cache size setting differs.
	 */
	writel(MT8183_SCP_CACHE_CON_WAYEN | MT8183_SCP_CACHESIZE_8KB,
	       scp->reg_base + MT8183_SCP_CACHE_CON);
	writel(MT8183_SCP_CACHESIZE_8KB, scp->reg_base + MT8183_SCP_DCACHE_CON);

	ret = scp_elf_load_segments(rproc, fw);
	clk_disable_unprepare(scp->clk);

	return ret;
}

static int scp_start(struct rproc *rproc)
{
	struct mtk_scp *scp = (struct mtk_scp *)rproc->priv;
	struct device *dev = scp->dev;
	struct scp_run *run = &scp->run;
	int ret;

	ret = clk_prepare_enable(scp->clk);
	if (ret) {
		dev_err(dev, "failed to enable clocks\n");
		return ret;
	}

	run->signaled = false;

	scp_reset_deassert(scp);

	ret = wait_event_interruptible_timeout(
					run->wq,
					run->signaled,
					msecs_to_jiffies(2000));

	if (ret == 0) {
		dev_err(dev, "wait SCP initialization timeout!\n");
		ret = -ETIME;
		goto stop;
	}
	if (ret == -ERESTARTSYS) {
		dev_err(dev, "wait SCP interrupted by a signal!\n");
		goto stop;
	}
	clk_disable_unprepare(scp->clk);
	dev_info(dev, "SCP is ready. FW version %s\n", run->fw_ver);

	return 0;

stop:
	scp_reset_assert(scp);
	clk_disable_unprepare(scp->clk);
	return ret;
}

static void *scp_da_to_va(struct rproc *rproc, u64 da, int len)
{
	struct mtk_scp *scp = (struct mtk_scp *)rproc->priv;
	int offset;

	if (da < scp->sram_size) {
		offset = da;
		if (offset >= 0 && (offset + len) < scp->sram_size)
			return (void __force *)scp->sram_base + offset;
	} else {
		offset = da - scp->phys_addr;
		if (offset >= 0 && (offset + len) < scp->dram_size)
			return (void __force *)scp->cpu_addr + offset;
	}

	return NULL;
}

static int scp_stop(struct rproc *rproc)
{
	struct mtk_scp *scp = (struct mtk_scp *)rproc->priv;
	int ret;

	ret = clk_prepare_enable(scp->clk);
	if (ret) {
		dev_err(scp->dev, "failed to enable clocks\n");
		return ret;
	}

	scp_reset_assert(scp);
	/* Disable SCP watchdog */
	writel(0, scp->reg_base + MT8183_WDT_CFG);
	clk_disable_unprepare(scp->clk);

	return 0;
}

static const struct rproc_ops scp_ops = {
	.start		= scp_start,
	.stop		= scp_stop,
	.load		= scp_load,
	.da_to_va	= scp_da_to_va,
};

/**
 * scp_get_device() - get device struct of SCP
 *
 * @scp:	mtk_scp structure
 **/
struct device *scp_get_device(struct mtk_scp *scp)
{
	return scp->dev;
}
EXPORT_SYMBOL_GPL(scp_get_device);

/**
 * scp_get_rproc() - get rproc struct of SCP
 *
 * @scp:	mtk_scp structure
 **/
struct rproc *scp_get_rproc(struct mtk_scp *scp)
{
	return scp->rproc;
}
EXPORT_SYMBOL_GPL(scp_get_rproc);

/**
 * scp_get_vdec_hw_capa() - get video decoder hardware capability
 *
 * @scp:	mtk_scp structure
 *
 * Return: video decoder hardware capability
 **/
unsigned int scp_get_vdec_hw_capa(struct mtk_scp *scp)
{
	return scp->run.dec_capability;
}
EXPORT_SYMBOL_GPL(scp_get_vdec_hw_capa);

/**
 * scp_get_venc_hw_capa() - get video encoder hardware capability
 *
 * @scp:	mtk_scp structure
 *
 * Return: video encoder hardware capability
 **/
unsigned int scp_get_venc_hw_capa(struct mtk_scp *scp)
{
	return scp->run.enc_capability;
}
EXPORT_SYMBOL_GPL(scp_get_venc_hw_capa);

/**
 * scp_mapping_dm_addr() - Mapping SRAM/DRAM to kernel virtual address
 *
 * @scp:	mtk_scp structure
 * @mem_addr:	SCP views memory address
 *
 * Mapping the SCP's SRAM address /
 * DMEM (Data Extended Memory) memory address /
 * Working buffer memory address to
 * kernel virtual address.
 *
 * Return: Return ERR_PTR(-EINVAL) if mapping failed,
 * otherwise the mapped kernel virtual address
 **/
void *scp_mapping_dm_addr(struct mtk_scp *scp, u32 mem_addr)
{
	void *ptr;

	ptr = scp_da_to_va(scp->rproc, mem_addr, 0);
	if (!ptr)
		return ERR_PTR(-EINVAL);

	return ptr;
}
EXPORT_SYMBOL_GPL(scp_mapping_dm_addr);

static int scp_map_memory_region(struct mtk_scp *scp)
{
	int ret;

	ret = of_reserved_mem_device_init(scp->dev);
	if (ret) {
		dev_err(scp->dev, "failed to assign memory-region: %d\n", ret);
		return -ENOMEM;
	}

	/* Reserved SCP code size */
	scp->dram_size = MAX_CODE_SIZE;
	scp->cpu_addr = dma_alloc_coherent(scp->dev, scp->dram_size,
					   &scp->phys_addr, GFP_KERNEL);
	if (!scp->cpu_addr)
		return -ENOMEM;

	return 0;
}

static void scp_unmap_memory_region(struct mtk_scp *scp)
{
	dma_free_coherent(scp->dev, scp->dram_size, scp->cpu_addr,
			  scp->phys_addr);
	of_reserved_mem_device_release(scp->dev);
}

static int scp_register_ipi(struct platform_device *pdev, u32 id,
			    ipi_handler_t handler, void *priv)
{
	struct mtk_scp *scp = platform_get_drvdata(pdev);

	return scp_ipi_register(scp, id, handler, priv);
}

static void scp_unregister_ipi(struct platform_device *pdev, u32 id)
{
	struct mtk_scp *scp = platform_get_drvdata(pdev);

	scp_ipi_unregister(scp, id);
}

static int scp_send_ipi(struct platform_device *pdev, u32 id, void *buf,
			unsigned int len, unsigned int wait)
{
	struct mtk_scp *scp = platform_get_drvdata(pdev);

	return scp_ipi_send(scp, id, buf, len, wait);
}

static struct mtk_rpmsg_info mtk_scp_rpmsg_info = {
	.send_ipi = scp_send_ipi,
	.register_ipi = scp_register_ipi,
	.unregister_ipi = scp_unregister_ipi,
	.ns_ipi_id = SCP_IPI_NS_SERVICE,
};

static void scp_add_rpmsg_subdev(struct mtk_scp *scp)
{
	scp->rpmsg_subdev =
		mtk_rpmsg_create_rproc_subdev(to_platform_device(scp->dev),
					      &mtk_scp_rpmsg_info);
	if (scp->rpmsg_subdev)
		rproc_add_subdev(scp->rproc, scp->rpmsg_subdev);
}

static void scp_remove_rpmsg_subdev(struct mtk_scp *scp)
{
	if (scp->rpmsg_subdev) {
		rproc_remove_subdev(scp->rproc, scp->rpmsg_subdev);
		mtk_rpmsg_destroy_rproc_subdev(scp->rpmsg_subdev);
		scp->rpmsg_subdev = NULL;
	}
}

static int scp_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct device_node *np = dev->of_node;
	struct mtk_scp *scp;
	struct rproc *rproc;
	struct resource *res;
	char *fw_name = "scp.img";
	int ret, i;

	rproc = rproc_alloc(dev,
			    np->name,
			    &scp_ops,
			    fw_name,
			    sizeof(*scp));
	if (!rproc) {
		dev_err(dev, "unable to allocate remoteproc\n");
		return -ENOMEM;
	}

	scp = (struct mtk_scp *)rproc->priv;
	scp->rproc = rproc;
	scp->dev = dev;
	platform_set_drvdata(pdev, scp);

	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "sram");
	scp->sram_base = devm_ioremap_resource(dev, res);
	if (IS_ERR((__force void *)scp->sram_base)) {
		dev_err(dev, "Failed to parse and map sram memory\n");
		ret = PTR_ERR((__force void *)scp->sram_base);
		goto free_rproc;
	}
	scp->sram_size = resource_size(res);

	mutex_init(&scp->send_lock);
	for (i = 0; i < SCP_IPI_MAX; i++)
		mutex_init(&scp->ipi_desc[i].lock);

	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "cfg");
	scp->reg_base = devm_ioremap_resource(dev, res);
	if (IS_ERR((__force void *)scp->reg_base)) {
		dev_err(dev, "Failed to parse and map cfg memory\n");
		ret = PTR_ERR((__force void *)scp->reg_base);
		goto destroy_mutex;
	}

	ret = scp_map_memory_region(scp);
	if (ret)
		goto destroy_mutex;

	scp->clk = devm_clk_get(dev, "main");
	if (IS_ERR(scp->clk)) {
		dev_err(dev, "Failed to get clock\n");
		ret = PTR_ERR(scp->clk);
		goto release_dev_mem;
	}

	ret = clk_prepare_enable(scp->clk);
	if (ret) {
		dev_err(dev, "failed to enable clocks\n");
		goto release_dev_mem;
	}

	ret = scp_ipi_init(scp);
	clk_disable_unprepare(scp->clk);
	if (ret) {
		dev_err(dev, "Failed to init ipi\n");
		goto release_dev_mem;
	}

	/* register SCP initialization IPI */
	ret = scp_ipi_register(scp, SCP_IPI_INIT, scp_init_ipi_handler, scp);
	if (ret) {
		dev_err(dev, "Failed to register IPI_SCP_INIT\n");
		goto release_dev_mem;
	}

	init_waitqueue_head(&scp->run.wq);
	init_waitqueue_head(&scp->ack_wq);

	scp_add_rpmsg_subdev(scp);

	ret = devm_request_threaded_irq(dev, platform_get_irq(pdev, 0), NULL,
					scp_irq_handler, IRQF_ONESHOT,
					pdev->name, scp);

	if (ret) {
		dev_err(dev, "failed to request irq\n");
		goto remove_subdev;
	}

	ret = rproc_add(rproc);
	if (ret)
		goto remove_subdev;

	return 0;

remove_subdev:
	scp_remove_rpmsg_subdev(scp);
	scp_ipi_unregister(scp, SCP_IPI_INIT);
release_dev_mem:
	scp_unmap_memory_region(scp);
destroy_mutex:
	for (i = 0; i < SCP_IPI_MAX; i++)
		mutex_destroy(&scp->ipi_desc[i].lock);
	mutex_destroy(&scp->send_lock);
free_rproc:
	rproc_free(rproc);

	return ret;
}

static int scp_remove(struct platform_device *pdev)
{
	struct mtk_scp *scp = platform_get_drvdata(pdev);
	int i;

	rproc_del(scp->rproc);
	scp_remove_rpmsg_subdev(scp);
	scp_ipi_unregister(scp, SCP_IPI_INIT);
	scp_unmap_memory_region(scp);
	for (i = 0; i < SCP_IPI_MAX; i++)
		mutex_destroy(&scp->ipi_desc[i].lock);
	mutex_destroy(&scp->send_lock);
	rproc_free(scp->rproc);

	return 0;
}

static const struct of_device_id mtk_scp_of_match[] = {
	{ .compatible = "mediatek,mt8183-scp"},
	{},
};
MODULE_DEVICE_TABLE(of, mtk_scp_of_match);

static struct platform_driver mtk_scp_driver = {
	.probe = scp_probe,
	.remove = scp_remove,
	.driver = {
		.name = "mtk-scp",
		.of_match_table = of_match_ptr(mtk_scp_of_match),
	},
};

module_platform_driver(mtk_scp_driver);

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("MediaTek SCP control driver");