[media] VPU: mediatek: support Mediatek VPU

The VPU driver for hw video codec embedded in Mediatek's MT8173 SOCs.
It is able to handle video decoding/encoding of in a range of formats.
The driver provides with VPU firmware download, memory management and
the communication interface between CPU and VPU.
For VPU initialization, it will create virtual memory for CPU access and
IOMMU address for vcodec hw device access. When a decode/encode instance
opens a device node, vpu driver will download vpu firmware to the device.
A decode/encode instant will decode/encode a frame using VPU
interface to interrupt vpu to handle decoding/encoding jobs.

Signed-off-by: Andrew-CT Chen <[e-mail]>
Signed-off-by: Tiffany Lin <[e-mail]>
[[e-mail]: drop unnecessary ARM || ARM64 dependency]
Signed-off-by: Hans Verkuil <[e-mail]>

Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/media/platform/Kconfig

···
 	   Coda is a range of video codec IPs that supports
 	   H.264, MPEG-4, and other video formats.
 
+config VIDEO_MEDIATEK_VPU
+	tristate "Mediatek Video Processor Unit"
+	depends on VIDEO_DEV && VIDEO_V4L2
+	depends on ARCH_MEDIATEK || COMPILE_TEST
+	---help---
+	    This driver provides downloading VPU firmware and
+	    communicating with VPU. This driver for hw video
+	    codec embedded in Mediatek's MT8173 SOCs. It is able
+	    to handle video decoding/encoding in a range of formats.
+
+	    To compile this driver as a module, choose M here: the
+	    module will be called mtk-vpu.
+
 config VIDEO_MEM2MEM_DEINTERLACE
 	tristate "Deinterlace support"
 	depends on VIDEO_DEV && VIDEO_V4L2 && DMA_ENGINE

drivers/media/platform/Makefile

···
 obj-$(CONFIG_VIDEO_RCAR_VIN)		+= rcar-vin/
 
 ccflags-y += -I$(srctree)/drivers/media/i2c
+
+obj-$(CONFIG_VIDEO_MEDIATEK_VPU)	+= mtk-vpu/

drivers/media/platform/mtk-vpu/Makefile

···
+mtk-vpu-y += mtk_vpu.o
+
+obj-$(CONFIG_VIDEO_MEDIATEK_VPU) += mtk-vpu.o

drivers/media/platform/mtk-vpu/mtk_vpu.c

···
+/*
+* Copyright (c) 2016 MediaTek Inc.
+* Author: Andrew-CT Chen <[e-mail]>
+*
+* This program is free software; you can redistribute it and/or modify
+* it under the terms of the GNU General Public License version 2 as
+* published by the Free Software Foundation.
+*
+* This program is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+* GNU General Public License for more details.
+*/
+#include <linux/clk.h>
+#include <linux/debugfs.h>
+#include <linux/firmware.h>
+#include <linux/interrupt.h>
+#include <linux/iommu.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+#include <linux/of_reserved_mem.h>
+#include <linux/sched.h>
+#include <linux/sizes.h>
+
+#include "mtk_vpu.h"
+
+/**
+ * VPU (video processor unit) is a tiny processor controlling video hardware
+ * related to video codec, scaling and color format converting.
+ * VPU interfaces with other blocks by share memory and interrupt.
+ **/
+
+#define INIT_TIMEOUT_MS		2000U
+#define IPI_TIMEOUT_MS		2000U
+#define VPU_FW_VER_LEN		16
+
+/* maximum program/data TCM (Tightly-Coupled Memory) size */
+#define VPU_PTCM_SIZE		(96 * SZ_1K)
+#define VPU_DTCM_SIZE		(32 * SZ_1K)
+/* the offset to get data tcm address */
+#define VPU_DTCM_OFFSET		0x18000UL
+/* daynamic allocated maximum extended memory size */
+#define VPU_EXT_P_SIZE		SZ_1M
+#define VPU_EXT_D_SIZE		SZ_4M
+/* maximum binary firmware size */
+#define VPU_P_FW_SIZE		(VPU_PTCM_SIZE + VPU_EXT_P_SIZE)
+#define VPU_D_FW_SIZE		(VPU_DTCM_SIZE + VPU_EXT_D_SIZE)
+/* the size of share buffer between Host and  VPU */
+#define SHARE_BUF_SIZE		48
+
+/* binary firmware name */
+#define VPU_P_FW		"vpu_p.bin"
+#define VPU_D_FW		"vpu_d.bin"
+
+#define VPU_RESET		0x0
+#define VPU_TCM_CFG		0x0008
+#define VPU_PMEM_EXT0_ADDR	0x000C
+#define VPU_PMEM_EXT1_ADDR	0x0010
+#define VPU_TO_HOST		0x001C
+#define VPU_DMEM_EXT0_ADDR	0x0014
+#define VPU_DMEM_EXT1_ADDR	0x0018
+#define HOST_TO_VPU		0x0024
+#define VPU_PC_REG		0x0060
+#define VPU_WDT_REG		0x0084
+
+/* vpu inter-processor communication interrupt */
+#define VPU_IPC_INT		BIT(8)
+
+/**
+ * enum vpu_fw_type - VPU firmware type
+ *
+ * @P_FW: program firmware
+ * @D_FW: data firmware
+ *
+ */
+enum vpu_fw_type {
+	P_FW,
+	D_FW,
+};
+
+/**
+ * struct vpu_mem - VPU extended program/data memory information
+ *
+ * @va:		the kernel virtual memory address of VPU extended memory
+ * @pa:		the physical memory address of VPU extended memory
+ *
+ */
+struct vpu_mem {
+	void *va;
+	dma_addr_t pa;
+};
+
+/**
+ * struct vpu_regs - VPU TCM and configuration registers
+ *
+ * @tcm:	the register for VPU Tightly-Coupled Memory
+ * @cfg:	the register for VPU configuration
+ * @irq:	the irq number for VPU interrupt
+ */
+struct vpu_regs {
+	void __iomem *tcm;
+	void __iomem *cfg;
+	int irq;
+};
+
+/**
+ * struct vpu_wdt_handler - VPU watchdog reset handler
+ *
+ * @reset_func:	reset handler
+ * @priv:	private data
+ */
+struct vpu_wdt_handler {
+	void (*reset_func)(void *);
+	void *priv;
+};
+
+/**
+ * struct vpu_wdt - VPU watchdog workqueue
+ *
+ * @handler:	VPU watchdog reset handler
+ * @ws:		workstruct for VPU watchdog
+ * @wq:		workqueue for VPU watchdog
+ */
+struct vpu_wdt {
+	struct vpu_wdt_handler handler[VPU_RST_MAX];
+	struct work_struct ws;
+	struct workqueue_struct *wq;
+};
+
+/**
+ * struct vpu_run - VPU initialization status
+ *
+ * @signaled:		the signal of vpu initialization completed
+ * @fw_ver:		VPU firmware version
+ * @enc_capability:	encoder capability which is not used for now and
+ *			the value is reserved for future use
+ * @wq:			wait queue for VPU initialization status
+ */
+struct vpu_run {
+	u32 signaled;
+	char fw_ver[VPU_FW_VER_LEN];
+	unsigned int	enc_capability;
+	wait_queue_head_t wq;
+};
+
+/**
+ * struct vpu_ipi_desc - VPU IPI descriptor
+ *
+ * @handler:	IPI handler
+ * @name:	the name of IPI handler
+ * @priv:	the private data of IPI handler
+ */
+struct vpu_ipi_desc {
+	ipi_handler_t handler;
+	const char *name;
+	void *priv;
+};
+
+/**
+ * struct share_obj - DTCM (Data Tightly-Coupled Memory) buffer shared with
+ *		      AP and VPU
+ *
+ * @id:		IPI id
+ * @len:	share buffer length
+ * @share_buf:	share buffer data
+ */
+struct share_obj {
+	s32 id;
+	u32 len;
+	unsigned char share_buf[SHARE_BUF_SIZE];
+};
+
+/**
+ * struct mtk_vpu - vpu driver data
+ * @extmem:		VPU extended memory information
+ * @reg:		VPU TCM and configuration registers
+ * @run:		VPU initialization status
+ * @ipi_desc:		VPU IPI descriptor
+ * @recv_buf:		VPU DTCM share buffer for receiving. The
+ *			receive buffer is only accessed in interrupt context.
+ * @send_buf:		VPU DTCM share buffer for sending
+ * @dev:		VPU struct device
+ * @clk:		VPU clock on/off
+ * @fw_loaded:		indicate VPU firmware loaded
+ * @enable_4GB:		VPU 4GB mode on/off
+ * @vpu_mutex:		protect mtk_vpu (except recv_buf) and ensure only
+ *			one client to use VPU service at a time. For example,
+ *			suppose a client is using VPU to decode VP8.
+ *			If the other client wants to encode VP8,
+ *			it has to wait until VP8 decode completes.
+ * @wdt_refcnt		WDT reference count to make sure the watchdog can be
+ *			disabled if no other client is using VPU service
+ * @ack_wq:		The wait queue for each codec and mdp. When sleeping
+ *			processes wake up, they will check the condition
+ *			"ipi_id_ack" to run the corresponding action or
+ *			go back to sleep.
+ * @ipi_id_ack:		The ACKs for registered IPI function sending
+ *			interrupt to VPU
+ *
+ */
+struct mtk_vpu {
+	struct vpu_mem extmem[2];
+	struct vpu_regs reg;
+	struct vpu_run run;
+	struct vpu_wdt wdt;
+	struct vpu_ipi_desc ipi_desc[IPI_MAX];
+	struct share_obj *recv_buf;
+	struct share_obj *send_buf;
+	struct device *dev;
+	struct clk *clk;
+	bool fw_loaded;
+	bool enable_4GB;
+	struct mutex vpu_mutex; /* for protecting vpu data data structure */
+	u32 wdt_refcnt;
+	wait_queue_head_t ack_wq;
+	bool ipi_id_ack[IPI_MAX];
+};
+
+static inline void vpu_cfg_writel(struct mtk_vpu *vpu, u32 val, u32 offset)
+{
+	writel(val, vpu->reg.cfg + offset);
+}
+
+static inline u32 vpu_cfg_readl(struct mtk_vpu *vpu, u32 offset)
+{
+	return readl(vpu->reg.cfg + offset);
+}
+
+static inline bool vpu_running(struct mtk_vpu *vpu)
+{
+	return vpu_cfg_readl(vpu, VPU_RESET) & BIT(0);
+}
+
+static void vpu_clock_disable(struct mtk_vpu *vpu)
+{
+	/* Disable VPU watchdog */
+	mutex_lock(&vpu->vpu_mutex);
+	if (!--vpu->wdt_refcnt)
+		vpu_cfg_writel(vpu,
+			       vpu_cfg_readl(vpu, VPU_WDT_REG) & ~(1L << 31),
+			       VPU_WDT_REG);
+	mutex_unlock(&vpu->vpu_mutex);
+
+	clk_disable(vpu->clk);
+}
+
+static int vpu_clock_enable(struct mtk_vpu *vpu)
+{
+	int ret;
+
+	ret = clk_enable(vpu->clk);
+	if (ret)
+		return ret;
+	/* Enable VPU watchdog */
+	mutex_lock(&vpu->vpu_mutex);
+	if (!vpu->wdt_refcnt++)
+		vpu_cfg_writel(vpu,
+			       vpu_cfg_readl(vpu, VPU_WDT_REG) | (1L << 31),
+			       VPU_WDT_REG);
+	mutex_unlock(&vpu->vpu_mutex);
+
+	return ret;
+}
+
+int vpu_ipi_register(struct platform_device *pdev,
+		     enum ipi_id id, ipi_handler_t handler,
+		     const char *name, void *priv)
+{
+	struct mtk_vpu *vpu = platform_get_drvdata(pdev);
+	struct vpu_ipi_desc *ipi_desc;
+
+	if (!vpu) {
+		dev_err(&pdev->dev, "vpu device in not ready\n");
+		return -EPROBE_DEFER;
+	}
+
+	if (id >= 0 && id < IPI_MAX && handler) {
+		ipi_desc = vpu->ipi_desc;
+		ipi_desc[id].name = name;
+		ipi_desc[id].handler = handler;
+		ipi_desc[id].priv = priv;
+		return 0;
+	}
+
+	dev_err(&pdev->dev, "register vpu ipi id %d with invalid arguments\n",
+		id);
+	return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(vpu_ipi_register);
+
+int vpu_ipi_send(struct platform_device *pdev,
+		 enum ipi_id id, void *buf,
+		 unsigned int len)
+{
+	struct mtk_vpu *vpu = platform_get_drvdata(pdev);
+	struct share_obj *send_obj = vpu->send_buf;
+	unsigned long timeout;
+	int ret = 0;
+
+	if (id <= IPI_VPU_INIT || id >= IPI_MAX ||
+	    len > sizeof(send_obj->share_buf) || !buf) {
+		dev_err(vpu->dev, "failed to send ipi message\n");
+		return -EINVAL;
+	}
+
+	ret = vpu_clock_enable(vpu);
+	if (ret) {
+		dev_err(vpu->dev, "failed to enable vpu clock\n");
+		return ret;
+	}
+	if (!vpu_running(vpu)) {
+		dev_err(vpu->dev, "vpu_ipi_send: VPU is not running\n");
+		ret = -EINVAL;
+		goto clock_disable;
+	}
+
+	mutex_lock(&vpu->vpu_mutex);
+
+	 /* Wait until VPU receives the last command */
+	timeout = jiffies + msecs_to_jiffies(IPI_TIMEOUT_MS);
+	do {
+		if (time_after(jiffies, timeout)) {
+			dev_err(vpu->dev, "vpu_ipi_send: IPI timeout!\n");
+			ret = -EIO;
+			goto mut_unlock;
+		}
+	} while (vpu_cfg_readl(vpu, HOST_TO_VPU));
+
+	memcpy((void *)send_obj->share_buf, buf, len);
+	send_obj->len = len;
+	send_obj->id = id;
+
+	vpu->ipi_id_ack[id] = false;
+	/* send the command to VPU */
+	vpu_cfg_writel(vpu, 0x1, HOST_TO_VPU);
+
+	mutex_unlock(&vpu->vpu_mutex);
+
+	/* wait for VPU's ACK */
+	timeout = msecs_to_jiffies(IPI_TIMEOUT_MS);
+	ret = wait_event_timeout(vpu->ack_wq, vpu->ipi_id_ack[id], timeout);
+	vpu->ipi_id_ack[id] = false;
+	if (ret == 0) {
+		dev_err(vpu->dev, "vpu ipi %d ack time out !", id);
+		ret = -EIO;
+		goto clock_disable;
+	}
+	vpu_clock_disable(vpu);
+
+	return 0;
+
+mut_unlock:
+	mutex_unlock(&vpu->vpu_mutex);
+clock_disable:
+	vpu_clock_disable(vpu);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(vpu_ipi_send);
+
+static void vpu_wdt_reset_func(struct work_struct *ws)
+{
+	struct vpu_wdt *wdt = container_of(ws, struct vpu_wdt, ws);
+	struct mtk_vpu *vpu = container_of(wdt, struct mtk_vpu, wdt);
+	struct vpu_wdt_handler *handler = wdt->handler;
+	int index, ret;
+
+	dev_info(vpu->dev, "vpu reset\n");
+	ret = vpu_clock_enable(vpu);
+	if (ret) {
+		dev_err(vpu->dev, "[VPU] wdt enables clock failed %d\n", ret);
+		return;
+	}
+	mutex_lock(&vpu->vpu_mutex);
+	vpu_cfg_writel(vpu, 0x0, VPU_RESET);
+	vpu->fw_loaded = false;
+	mutex_unlock(&vpu->vpu_mutex);
+	vpu_clock_disable(vpu);
+
+	for (index = 0; index < VPU_RST_MAX; index++) {
+		if (handler[index].reset_func) {
+			handler[index].reset_func(handler[index].priv);
+			dev_dbg(vpu->dev, "wdt handler func %d\n", index);
+		}
+	}
+}
+
+int vpu_wdt_reg_handler(struct platform_device *pdev,
+			void wdt_reset(void *),
+			void *priv, enum rst_id id)
+{
+	struct mtk_vpu *vpu = platform_get_drvdata(pdev);
+	struct vpu_wdt_handler *handler;
+
+	if (!vpu) {
+		dev_err(&pdev->dev, "vpu device in not ready\n");
+		return -EPROBE_DEFER;
+	}
+
+	handler = vpu->wdt.handler;
+
+	if (id >= 0 && id < VPU_RST_MAX && wdt_reset) {
+		dev_dbg(vpu->dev, "wdt register id %d\n", id);
+		mutex_lock(&vpu->vpu_mutex);
+		handler[id].reset_func = wdt_reset;
+		handler[id].priv = priv;
+		mutex_unlock(&vpu->vpu_mutex);
+		return 0;
+	}
+
+	dev_err(vpu->dev, "register vpu wdt handler failed\n");
+	return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(vpu_wdt_reg_handler);
+
+unsigned int vpu_get_venc_hw_capa(struct platform_device *pdev)
+{
+	struct mtk_vpu *vpu = platform_get_drvdata(pdev);
+
+	return vpu->run.enc_capability;
+}
+EXPORT_SYMBOL_GPL(vpu_get_venc_hw_capa);
+
+void *vpu_mapping_dm_addr(struct platform_device *pdev,
+			  u32 dtcm_dmem_addr)
+{
+	struct mtk_vpu *vpu = platform_get_drvdata(pdev);
+
+	if (!dtcm_dmem_addr ||
+	    (dtcm_dmem_addr > (VPU_DTCM_SIZE + VPU_EXT_D_SIZE))) {
+		dev_err(vpu->dev, "invalid virtual data memory address\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	if (dtcm_dmem_addr < VPU_DTCM_SIZE)
+		return (__force void *)(dtcm_dmem_addr + vpu->reg.tcm +
+					VPU_DTCM_OFFSET);
+
+	return vpu->extmem[D_FW].va + (dtcm_dmem_addr - VPU_DTCM_SIZE);
+}
+EXPORT_SYMBOL_GPL(vpu_mapping_dm_addr);
+
+struct platform_device *vpu_get_plat_device(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *vpu_node;
+	struct platform_device *vpu_pdev;
+
+	vpu_node = of_parse_phandle(dev->of_node, "mediatek,vpu", 0);
+	if (!vpu_node) {
+		dev_err(dev, "can't get vpu node\n");
+		return NULL;
+	}
+
+	vpu_pdev = of_find_device_by_node(vpu_node);
+	if (WARN_ON(!vpu_pdev)) {
+		dev_err(dev, "vpu pdev failed\n");
+		of_node_put(vpu_node);
+		return NULL;
+	}
+
+	return vpu_pdev;
+}
+EXPORT_SYMBOL_GPL(vpu_get_plat_device);
+
+/* load vpu program/data memory */
+static int load_requested_vpu(struct mtk_vpu *vpu,
+			      const struct firmware *vpu_fw,
+			      u8 fw_type)
+{
+	size_t tcm_size = fw_type ? VPU_DTCM_SIZE : VPU_PTCM_SIZE;
+	size_t fw_size = fw_type ? VPU_D_FW_SIZE : VPU_P_FW_SIZE;
+	char *fw_name = fw_type ? VPU_D_FW : VPU_P_FW;
+	size_t dl_size = 0;
+	size_t extra_fw_size = 0;
+	void *dest;
+	int ret;
+
+	ret = request_firmware(&vpu_fw, fw_name, vpu->dev);
+	if (ret < 0) {
+		dev_err(vpu->dev, "Failed to load %s, %d\n", fw_name, ret);
+		return ret;
+	}
+	dl_size = vpu_fw->size;
+	if (dl_size > fw_size) {
+		dev_err(vpu->dev, "fw %s size %zu is abnormal\n", fw_name,
+			dl_size);
+		release_firmware(vpu_fw);
+		return  -EFBIG;
+	}
+	dev_dbg(vpu->dev, "Downloaded fw %s size: %zu.\n",
+		fw_name,
+		dl_size);
+	/* reset VPU */
+	vpu_cfg_writel(vpu, 0x0, VPU_RESET);
+
+	/* handle extended firmware size */
+	if (dl_size > tcm_size) {
+		dev_dbg(vpu->dev, "fw size %zu > limited fw size %zu\n",
+			dl_size, tcm_size);
+		extra_fw_size = dl_size - tcm_size;
+		dev_dbg(vpu->dev, "extra_fw_size %zu\n", extra_fw_size);
+		dl_size = tcm_size;
+	}
+	dest = (__force void *)vpu->reg.tcm;
+	if (fw_type == D_FW)
+		dest += VPU_DTCM_OFFSET;
+	memcpy(dest, vpu_fw->data, dl_size);
+	/* download to extended memory if need */
+	if (extra_fw_size > 0) {
+		dest = vpu->extmem[fw_type].va;
+		dev_dbg(vpu->dev, "download extended memory type %x\n",
+			fw_type);
+		memcpy(dest, vpu_fw->data + tcm_size, extra_fw_size);
+	}
+
+	release_firmware(vpu_fw);
+
+	return 0;
+}
+
+int vpu_load_firmware(struct platform_device *pdev)
+{
+	struct mtk_vpu *vpu = platform_get_drvdata(pdev);
+	struct device *dev = &pdev->dev;
+	struct vpu_run *run = &vpu->run;
+	const struct firmware *vpu_fw = NULL;
+	int ret;
+
+	if (!pdev) {
+		dev_err(dev, "VPU platform device is invalid\n");
+		return -EINVAL;
+	}
+
+	mutex_lock(&vpu->vpu_mutex);
+	if (vpu->fw_loaded) {
+		mutex_unlock(&vpu->vpu_mutex);
+		return 0;
+	}
+	mutex_unlock(&vpu->vpu_mutex);
+
+	ret = vpu_clock_enable(vpu);
+	if (ret) {
+		dev_err(dev, "enable clock failed %d\n", ret);
+		return ret;
+	}
+
+	mutex_lock(&vpu->vpu_mutex);
+
+	run->signaled = false;
+	dev_dbg(vpu->dev, "firmware request\n");
+	/* Downloading program firmware to device*/
+	ret = load_requested_vpu(vpu, vpu_fw, P_FW);
+	if (ret < 0) {
+		dev_err(dev, "Failed to request %s, %d\n", VPU_P_FW, ret);
+		goto OUT_LOAD_FW;
+	}
+
+	/* Downloading data firmware to device */
+	ret = load_requested_vpu(vpu, vpu_fw, D_FW);
+	if (ret < 0) {
+		dev_err(dev, "Failed to request %s, %d\n", VPU_D_FW, ret);
+		goto OUT_LOAD_FW;
+	}
+
+	vpu->fw_loaded = true;
+	/* boot up vpu */
+	vpu_cfg_writel(vpu, 0x1, VPU_RESET);
+
+	ret = wait_event_interruptible_timeout(run->wq,
+					       run->signaled,
+					       msecs_to_jiffies(INIT_TIMEOUT_MS)
+					       );
+	if (ret == 0) {
+		ret = -ETIME;
+		dev_err(dev, "wait vpu initialization timout!\n");
+		goto OUT_LOAD_FW;
+	} else if (-ERESTARTSYS == ret) {
+		dev_err(dev, "wait vpu interrupted by a signal!\n");
+		goto OUT_LOAD_FW;
+	}
+
+	ret = 0;
+	dev_info(dev, "vpu is ready. Fw version %s\n", run->fw_ver);
+
+OUT_LOAD_FW:
+	mutex_unlock(&vpu->vpu_mutex);
+	vpu_clock_disable(vpu);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(vpu_load_firmware);
+
+static void vpu_init_ipi_handler(void *data, unsigned int len, void *priv)
+{
+	struct mtk_vpu *vpu = (struct mtk_vpu *)priv;
+	struct vpu_run *run = (struct vpu_run *)data;
+
+	vpu->run.signaled = run->signaled;
+	strncpy(vpu->run.fw_ver, run->fw_ver, VPU_FW_VER_LEN);
+	vpu->run.enc_capability = run->enc_capability;
+	wake_up_interruptible(&vpu->run.wq);
+}
+
+#ifdef CONFIG_DEBUG_FS
+static ssize_t vpu_debug_read(struct file *file, char __user *user_buf,
+			      size_t count, loff_t *ppos)
+{
+	char buf[256];
+	unsigned int len;
+	unsigned int running, pc, vpu_to_host, host_to_vpu, wdt;
+	int ret;
+	struct device *dev = file->private_data;
+	struct mtk_vpu *vpu = dev_get_drvdata(dev);
+
+	ret = vpu_clock_enable(vpu);
+	if (ret) {
+		dev_err(vpu->dev, "[VPU] enable clock failed %d\n", ret);
+		return 0;
+	}
+
+	/* vpu register status */
+	running = vpu_running(vpu);
+	pc = vpu_cfg_readl(vpu, VPU_PC_REG);
+	wdt = vpu_cfg_readl(vpu, VPU_WDT_REG);
+	host_to_vpu = vpu_cfg_readl(vpu, HOST_TO_VPU);
+	vpu_to_host = vpu_cfg_readl(vpu, VPU_TO_HOST);
+	vpu_clock_disable(vpu);
+
+	if (running) {
+		len = snprintf(buf, sizeof(buf), "VPU is running\n\n"
+		"FW Version: %s\n"
+		"PC: 0x%x\n"
+		"WDT: 0x%x\n"
+		"Host to VPU: 0x%x\n"
+		"VPU to Host: 0x%x\n",
+		vpu->run.fw_ver, pc, wdt,
+		host_to_vpu, vpu_to_host);
+	} else {
+		len = snprintf(buf, sizeof(buf), "VPU not running\n");
+	}
+
+	return simple_read_from_buffer(user_buf, count, ppos, buf, len);
+}
+
+static const struct file_operations vpu_debug_fops = {
+	.open = simple_open,
+	.read = vpu_debug_read,
+};
+#endif /* CONFIG_DEBUG_FS */
+
+static void vpu_free_ext_mem(struct mtk_vpu *vpu, u8 fw_type)
+{
+	struct device *dev = vpu->dev;
+	size_t fw_ext_size = fw_type ? VPU_EXT_D_SIZE : VPU_EXT_P_SIZE;
+
+	dma_free_coherent(dev, fw_ext_size, vpu->extmem[fw_type].va,
+			  vpu->extmem[fw_type].pa);
+}
+
+static int vpu_alloc_ext_mem(struct mtk_vpu *vpu, u32 fw_type)
+{
+	struct device *dev = vpu->dev;
+	size_t fw_ext_size = fw_type ? VPU_EXT_D_SIZE : VPU_EXT_P_SIZE;
+	u32 vpu_ext_mem0 = fw_type ? VPU_DMEM_EXT0_ADDR : VPU_PMEM_EXT0_ADDR;
+	u32 vpu_ext_mem1 = fw_type ? VPU_DMEM_EXT1_ADDR : VPU_PMEM_EXT1_ADDR;
+	u32 offset_4gb = vpu->enable_4GB ? 0x40000000 : 0;
+
+	vpu->extmem[fw_type].va = dma_alloc_coherent(dev,
+					       fw_ext_size,
+					       &vpu->extmem[fw_type].pa,
+					       GFP_KERNEL);
+	if (!vpu->extmem[fw_type].va) {
+		dev_err(dev, "Failed to allocate the extended program memory\n");
+		return PTR_ERR(vpu->extmem[fw_type].va);
+	}
+
+	/* Disable extend0. Enable extend1 */
+	vpu_cfg_writel(vpu, 0x1, vpu_ext_mem0);
+	vpu_cfg_writel(vpu, (vpu->extmem[fw_type].pa & 0xFFFFF000) + offset_4gb,
+		       vpu_ext_mem1);
+
+	dev_info(dev, "%s extend memory phy=0x%llx virt=0x%p\n",
+		 fw_type ? "Data" : "Program",
+		 (unsigned long long)vpu->extmem[fw_type].pa,
+		 vpu->extmem[fw_type].va);
+
+	return 0;
+}
+
+static void vpu_ipi_handler(struct mtk_vpu *vpu)
+{
+	struct share_obj *rcv_obj = vpu->recv_buf;
+	struct vpu_ipi_desc *ipi_desc = vpu->ipi_desc;
+
+	if (rcv_obj->id < IPI_MAX && ipi_desc[rcv_obj->id].handler) {
+		ipi_desc[rcv_obj->id].handler(rcv_obj->share_buf,
+					      rcv_obj->len,
+					      ipi_desc[rcv_obj->id].priv);
+		if (rcv_obj->id > IPI_VPU_INIT) {
+			vpu->ipi_id_ack[rcv_obj->id] = true;
+			wake_up(&vpu->ack_wq);
+		}
+	} else {
+		dev_err(vpu->dev, "No such ipi id = %d\n", rcv_obj->id);
+	}
+}
+
+static int vpu_ipi_init(struct mtk_vpu *vpu)
+{
+	/* Disable VPU to host interrupt */
+	vpu_cfg_writel(vpu, 0x0, VPU_TO_HOST);
+
+	/* shared buffer initialization */
+	vpu->recv_buf = (__force struct share_obj *)(vpu->reg.tcm +
+						     VPU_DTCM_OFFSET);
+	vpu->send_buf = vpu->recv_buf + 1;
+	memset(vpu->recv_buf, 0, sizeof(struct share_obj));
+	memset(vpu->send_buf, 0, sizeof(struct share_obj));
+
+	return 0;
+}
+
+static irqreturn_t vpu_irq_handler(int irq, void *priv)
+{
+	struct mtk_vpu *vpu = priv;
+	u32 vpu_to_host;
+	int ret;
+
+	/*
+	 * Clock should have been enabled already.
+	 * Enable again in case vpu_ipi_send times out
+	 * and has disabled the clock.
+	 */
+	ret = clk_enable(vpu->clk);
+	if (ret) {
+		dev_err(vpu->dev, "[VPU] enable clock failed %d\n", ret);
+		return IRQ_NONE;
+	}
+	vpu_to_host = vpu_cfg_readl(vpu, VPU_TO_HOST);
+	if (vpu_to_host & VPU_IPC_INT) {
+		vpu_ipi_handler(vpu);
+	} else {
+		dev_err(vpu->dev, "vpu watchdog timeout! 0x%x", vpu_to_host);
+		queue_work(vpu->wdt.wq, &vpu->wdt.ws);
+	}
+
+	/* VPU won't send another interrupt until we set VPU_TO_HOST to 0. */
+	vpu_cfg_writel(vpu, 0x0, VPU_TO_HOST);
+	clk_disable(vpu->clk);
+
+	return IRQ_HANDLED;
+}
+
+#ifdef CONFIG_DEBUG_FS
+static struct dentry *vpu_debugfs;
+#endif
+static int mtk_vpu_probe(struct platform_device *pdev)
+{
+	struct mtk_vpu *vpu;
+	struct device *dev;
+	struct resource *res;
+	int ret = 0;
+
+	dev_dbg(&pdev->dev, "initialization\n");
+
+	dev = &pdev->dev;
+	vpu = devm_kzalloc(dev, sizeof(*vpu), GFP_KERNEL);
+	if (!vpu)
+		return -ENOMEM;
+
+	vpu->dev = &pdev->dev;
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "tcm");
+	vpu->reg.tcm = devm_ioremap_resource(dev, res);
+	if (IS_ERR((__force void *)vpu->reg.tcm)) {
+		dev_err(dev, "devm_ioremap_resource vpu tcm failed.\n");
+		return PTR_ERR((__force void *)vpu->reg.tcm);
+	}
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "cfg_reg");
+	vpu->reg.cfg = devm_ioremap_resource(dev, res);
+	if (IS_ERR((__force void *)vpu->reg.cfg)) {
+		dev_err(dev, "devm_ioremap_resource vpu cfg failed.\n");
+		return PTR_ERR((__force void *)vpu->reg.cfg);
+	}
+
+	/* Get VPU clock */
+	vpu->clk = devm_clk_get(dev, "main");
+	if (!vpu->clk) {
+		dev_err(dev, "get vpu clock failed\n");
+		return -EINVAL;
+	}
+
+	platform_set_drvdata(pdev, vpu);
+
+	ret = clk_prepare(vpu->clk);
+	if (ret) {
+		dev_err(dev, "prepare vpu clock failed\n");
+		return ret;
+	}
+
+	/* VPU watchdog */
+	vpu->wdt.wq = create_singlethread_workqueue("vpu_wdt");
+	if (!vpu->wdt.wq) {
+		dev_err(dev, "initialize wdt workqueue failed\n");
+		return -ENOMEM;
+	}
+	INIT_WORK(&vpu->wdt.ws, vpu_wdt_reset_func);
+	mutex_init(&vpu->vpu_mutex);
+
+	ret = vpu_clock_enable(vpu);
+	if (ret) {
+		dev_err(dev, "enable vpu clock failed\n");
+		goto workqueue_destroy;
+	}
+
+	dev_dbg(dev, "vpu ipi init\n");
+	ret = vpu_ipi_init(vpu);
+	if (ret) {
+		dev_err(dev, "Failed to init ipi\n");
+		goto disable_vpu_clk;
+	}
+
+	/* register vpu initialization IPI */
+	ret = vpu_ipi_register(pdev, IPI_VPU_INIT, vpu_init_ipi_handler,
+			       "vpu_init", vpu);
+	if (ret) {
+		dev_err(dev, "Failed to register IPI_VPU_INIT\n");
+		goto vpu_mutex_destroy;
+	}
+
+#ifdef CONFIG_DEBUG_FS
+	vpu_debugfs = debugfs_create_file("mtk_vpu", S_IRUGO, NULL, (void *)dev,
+					  &vpu_debug_fops);
+	if (!vpu_debugfs) {
+		ret = -ENOMEM;
+		goto cleanup_ipi;
+	}
+#endif
+
+	/* Set PTCM to 96K and DTCM to 32K */
+	vpu_cfg_writel(vpu, 0x2, VPU_TCM_CFG);
+
+	vpu->enable_4GB = !!(totalram_pages > (SZ_2G >> PAGE_SHIFT));
+	dev_info(dev, "4GB mode %u\n", vpu->enable_4GB);
+
+	if (vpu->enable_4GB) {
+		ret = of_reserved_mem_device_init(dev);
+		if (ret)
+			dev_info(dev, "init reserved memory failed\n");
+			/* continue to use dynamic allocation if failed */
+	}
+
+	ret = vpu_alloc_ext_mem(vpu, D_FW);
+	if (ret) {
+		dev_err(dev, "Allocate DM failed\n");
+		goto remove_debugfs;
+	}
+
+	ret = vpu_alloc_ext_mem(vpu, P_FW);
+	if (ret) {
+		dev_err(dev, "Allocate PM failed\n");
+		goto free_d_mem;
+	}
+
+	init_waitqueue_head(&vpu->run.wq);
+	init_waitqueue_head(&vpu->ack_wq);
+
+	res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+	if (!res) {
+		dev_err(dev, "get IRQ resource failed.\n");
+		ret = -ENXIO;
+		goto free_p_mem;
+	}
+	vpu->reg.irq = platform_get_irq(pdev, 0);
+	ret = devm_request_irq(dev, vpu->reg.irq, vpu_irq_handler, 0,
+			       pdev->name, vpu);
+	if (ret) {
+		dev_err(dev, "failed to request irq\n");
+		goto free_p_mem;
+	}
+
+	vpu_clock_disable(vpu);
+	dev_dbg(dev, "initialization completed\n");
+
+	return 0;
+
+free_p_mem:
+	vpu_free_ext_mem(vpu, P_FW);
+free_d_mem:
+	vpu_free_ext_mem(vpu, D_FW);
+remove_debugfs:
+	of_reserved_mem_device_release(dev);
+#ifdef CONFIG_DEBUG_FS
+	debugfs_remove(vpu_debugfs);
+cleanup_ipi:
+#endif
+	memset(vpu->ipi_desc, 0, sizeof(struct vpu_ipi_desc) * IPI_MAX);
+vpu_mutex_destroy:
+	mutex_destroy(&vpu->vpu_mutex);
+disable_vpu_clk:
+	vpu_clock_disable(vpu);
+workqueue_destroy:
+	destroy_workqueue(vpu->wdt.wq);
+
+	return ret;
+}
+
+static const struct of_device_id mtk_vpu_match[] = {
+	{
+		.compatible = "mediatek,mt8173-vpu",
+	},
+	{},
+};
+MODULE_DEVICE_TABLE(of, mtk_vpu_match);
+
+static int mtk_vpu_remove(struct platform_device *pdev)
+{
+	struct mtk_vpu *vpu = platform_get_drvdata(pdev);
+
+#ifdef CONFIG_DEBUG_FS
+	debugfs_remove(vpu_debugfs);
+#endif
+	if (vpu->wdt.wq) {
+		flush_workqueue(vpu->wdt.wq);
+		destroy_workqueue(vpu->wdt.wq);
+	}
+	vpu_free_ext_mem(vpu, P_FW);
+	vpu_free_ext_mem(vpu, D_FW);
+	mutex_destroy(&vpu->vpu_mutex);
+	clk_unprepare(vpu->clk);
+
+	return 0;
+}
+
+static struct platform_driver mtk_vpu_driver = {
+	.probe	= mtk_vpu_probe,
+	.remove	= mtk_vpu_remove,
+	.driver	= {
+		.name	= "mtk_vpu",
+		.of_match_table = mtk_vpu_match,
+	},
+};
+
+module_platform_driver(mtk_vpu_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Mediatek Video Prosessor Unit driver");

drivers/media/platform/mtk-vpu/mtk_vpu.h

···
+/*
+* Copyright (c) 2016 MediaTek Inc.
+* Author: Andrew-CT Chen <[e-mail]>
+*
+* This program is free software; you can redistribute it and/or modify
+* it under the terms of the GNU General Public License version 2 as
+* published by the Free Software Foundation.
+*
+* This program is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+* GNU General Public License for more details.
+*/
+
+#ifndef _MTK_VPU_H
+#define _MTK_VPU_H
+
+#include <linux/platform_device.h>
+
+/**
+ * VPU (video processor unit) is a tiny processor controlling video hardware
+ * related to video codec, scaling and color format converting.
+ * VPU interfaces with other blocks by share memory and interrupt.
+ **/
+
+typedef void (*ipi_handler_t) (void *data,
+			       unsigned int len,
+			       void *priv);
+
+/**
+ * enum ipi_id - the id of inter-processor interrupt
+ *
+ * @IPI_VPU_INIT:	 The interrupt from vpu is to notfiy kernel
+			 VPU initialization completed.
+			 IPI_VPU_INIT is sent from VPU when firmware is
+			 loaded. AP doesn't need to send IPI_VPU_INIT
+			 command to VPU.
+			 For other IPI below, AP should send the request
+			 to VPU to trigger the interrupt.
+ * @IPI_VENC_H264:	 The interrupt from vpu is to notify kernel to
+			 handle H264 video encoder job, and vice versa.
+ * @IPI_VENC_VP8:	 The interrupt fro vpu is to notify kernel to
+			 handle VP8 video encoder job,, and vice versa.
+ * @IPI_MAX:		 The maximum IPI number
+ */
+
+enum ipi_id {
+	IPI_VPU_INIT = 0,
+	IPI_VENC_H264,
+	IPI_VENC_VP8,
+	IPI_MAX,
+};
+
+/**
+ * enum rst_id - reset id to register reset function for VPU watchdog timeout
+ *
+ * @VPU_RST_ENC: encoder reset id
+ * @VPU_RST_MAX: maximum reset id
+ */
+enum rst_id {
+	VPU_RST_ENC,
+	VPU_RST_MAX,
+};
+
+/**
+ * vpu_ipi_register - register an ipi function
+ *
+ * @pdev:	VPU platform device
+ * @id:		IPI ID
+ * @handler:	IPI handler
+ * @name:	IPI name
+ * @priv:	private data for IPI handler
+ *
+ * Register an ipi function to receive ipi interrupt from VPU.
+ *
+ * Return: Return 0 if ipi registers successfully, otherwise it is failed.
+ */
+int vpu_ipi_register(struct platform_device *pdev, enum ipi_id id,
+		     ipi_handler_t handler, const char *name, void *priv);
+
+/**
+ * vpu_ipi_send - send data from AP to vpu.
+ *
+ * @pdev:	VPU platform device
+ * @id:		IPI ID
+ * @buf:	the data buffer
+ * @len:	the data buffer length
+ *
+ * This function is thread-safe. When this function returns,
+ * VPU has received the data and starts the processing.
+ * When the processing completes, IPI handler registered
+ * by vpu_ipi_register will be called in interrupt context.
+ *
+ * Return: Return 0 if sending data successfully, otherwise it is failed.
+ **/
+int vpu_ipi_send(struct platform_device *pdev,
+		 enum ipi_id id, void *buf,
+		 unsigned int len);
+
+/**
+ * vpu_get_plat_device - get VPU's platform device
+ *
+ * @pdev:	the platform device of the module requesting VPU platform
+ *		device for using VPU API.
+ *
+ * Return: Return NULL if it is failed.
+ * otherwise it is VPU's platform device
+ **/
+struct platform_device *vpu_get_plat_device(struct platform_device *pdev);
+
+/**
+ * vpu_wdt_reg_handler - register a VPU watchdog handler
+ *
+ * @pdev:               VPU platform device
+ * @vpu_wdt_reset_func:	the callback reset function
+ * @private_data:       the private data for reset function
+ * @rst_id:		reset id
+ *
+ * Register a handler performing own tasks when vpu reset by watchdog
+ *
+ * Return: Return 0 if the handler is added successfully,
+ * otherwise it is failed.
+ *
+ **/
+int vpu_wdt_reg_handler(struct platform_device *pdev,
+			void vpu_wdt_reset_func(void *),
+			void *priv, enum rst_id id);
+/**
+ * vpu_get_venc_hw_capa - get video encoder hardware capability
+ *
+ * @pdev:	VPU platform device
+ *
+ * Return: video encoder hardware capability
+ **/
+unsigned int vpu_get_venc_hw_capa(struct platform_device *pdev);
+
+/**
+ * vpu_load_firmware - download VPU firmware and boot it
+ *
+ * @pdev:	VPU platform device
+ *
+ * Return: Return 0 if downloading firmware successfully,
+ * otherwise it is failed
+ **/
+int vpu_load_firmware(struct platform_device *pdev);
+
+/**
+ * vpu_mapping_dm_addr - Mapping DTCM/DMEM to kernel virtual address
+ *
+ * @pdev:	VPU platform device
+ * @dmem_addr:	VPU's data memory address
+ *
+ * Mapping the VPU's DTCM (Data Tightly-Coupled Memory) /
+ * DMEM (Data Extended Memory) memory address to
+ * kernel virtual address.
+ *
+ * Return: Return ERR_PTR(-EINVAL) if mapping failed,
+ * otherwise the mapped kernel virtual address
+ **/
+void *vpu_mapping_dm_addr(struct platform_device *pdev,
+			  u32 dtcm_dmem_addr);
+#endif /* _MTK_VPU_H */