Re: [RESEND RFC/PATCH 3/8] media: platform: mtk-vpu: Support Mediatek VPU

Daniel Thompson
2015-11-25T16:11:45Z

On 17/11/15 12:54, Tiffany Lin wrote:
> From: Andrew-CT Chen <andrew-ct.chen@mediatek.com>
>
> 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 <andrew-ct.chen@mediatek.com>
> ---
> drivers/media/platform/Kconfig | 6 +
> drivers/media/platform/Makefile | 2 +
> drivers/media/platform/mtk-vpu/Makefile | 1 +
> .../platform/mtk-vpu/h264_enc/venc_h264_vpu.h | 127 +++
> .../media/platform/mtk-vpu/include/venc_ipi_msg.h | 212 +++++
> drivers/media/platform/mtk-vpu/mtk_vpu_core.c | 823 ++++++++++++++++++++
> drivers/media/platform/mtk-vpu/mtk_vpu_core.h | 161 ++++
> .../media/platform/mtk-vpu/vp8_enc/venc_vp8_vpu.h | 119 +++
> 8 files changed, 1451 insertions(+)
> create mode 100644 drivers/media/platform/mtk-vpu/Makefile
> create mode 100644 drivers/media/platform/mtk-vpu/h264_enc/venc_h264_vpu.h
> create mode 100644 drivers/media/platform/mtk-vpu/include/venc_ipi_msg.h
> create mode 100644 drivers/media/platform/mtk-vpu/mtk_vpu_core.c
> create mode 100644 drivers/media/platform/mtk-vpu/mtk_vpu_core.h
> create mode 100644 drivers/media/platform/mtk-vpu/vp8_enc/venc_vp8_vpu.h
>
> diff --git a/drivers/media/platform/Kconfig b/drivers/media/platform/Kconfig
> index ccbc974..f98eb47 100644
> --- a/drivers/media/platform/Kconfig
> +++ b/drivers/media/platform/Kconfig
> @@ -148,6 +148,12 @@ config VIDEO_CODA
> Coda is a range of video codec IPs that supports
> H.264, MPEG-4, and other video formats.
>
> +config MEDIATEK_VPU
> + bool "Mediatek Video Processor Unit"
> + ---help---
> + This driver provides downloading firmware vpu and
> + communicating with vpu.
> +

This looks pretty broken.

Shouldn't this option be tristate? Why are there no depends-on or selects?

Also I think the help text could be more descriptive here (and so does
checkpatch ;-) ).

> diff --git a/drivers/media/platform/mtk-vpu/h264_enc/venc_h264_vpu.h b/drivers/media/platform/mtk-vpu/h264_enc/venc_h264_vpu.h
> new file mode 100644
> index 0000000..9c8ebdd
> --- /dev/null
> +++ b/drivers/media/platform/mtk-vpu/h264_enc/venc_h264_vpu.h

Why is this file included in *this* patch? It is not included by
anything in the patch and defines functions that do not exist yet.

> diff --git a/drivers/media/platform/mtk-vpu/include/venc_ipi_msg.h b/drivers/media/platform/mtk-vpu/include/venc_ipi_msg.h
> new file mode 100644
> index 0000000..a345b98

This file also is not included by anything and should, perhaps be
included in a different patch.

> diff --git a/drivers/media/platform/mtk-vpu/mtk_vpu_core.c b/drivers/media/platform/mtk-vpu/mtk_vpu_core.c
> new file mode 100644
> index 0000000..b524dbc
> --- /dev/null
> +++ b/drivers/media/platform/mtk-vpu/mtk_vpu_core.c
> @@ -0,0 +1,823 @@
> +/*
> +* Copyright (c) 2015 MediaTek Inc.
> +* Author: Andrew-CT Chen <andrew-ct.chen@mediatek.com>
> +*
> +* 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/sched.h>
> +#include <linux/sizes.h>
> +
> +#include "mtk_vpu_core.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 MTK_VPU_DRV_NAME "mtk_vpu"

This is only used once, why not just put this string directly into the
.name field?

> +
> +#define INIT_TIMEOUT_MS 2000U
> +#define IPI_TIMEOUT_MS 2000U
> +#define VPU_FW_VER_LEN 16
> +
> +/* vpu extended virtural address */
> +#define VPU_PMEM0_VIRT(vpu) ((vpu)->mem.p_va)
> +#define VPU_DMEM0_VIRT(vpu) ((vpu)->mem.d_va)
> +/* vpu extended iova address*/
> +#define VPU_PMEM0_IOVA(vpu) ((vpu)->mem.p_iova)
> +#define VPU_DMEM0_IOVA(vpu) ((vpu)->mem.d_iova)

These feel like obfuscation to me. The code looks clearer without the
macro For example:

vpu->mem.p_va = dma_alloc_coherent(dev, ...);

Is much clearer than:

VPU_PMEM0_VIRT(vpu) = dma_alloc_coherent(dev, ...);

> +
> +#define VPU_PTCM(dev) ((dev)->reg.sram)
> +#define VPU_DTCM(dev) ((dev)->reg.sram + VPU_DTCM_OFFSET)

These macros also seem to add very little value. They are consumed only
a couple of times and only serve to conceal how the sram is mapped and
consumed:

dest = vpu->reg.sram;
if (fw_type == D_FW)
dest += VPU_DTCM_OFFSET;

Compared to:

dest = fw_type ? VPU_DTCM(vpu) : VPU_PTCM(vpu);

> +
> +#define VPU_PTCM_SIZE (96 * SZ_1K)
> +#define VPU_DTCM_SIZE (32 * SZ_1K)
> +#define VPU_DTCM_OFFSET 0x18000UL
> +#define VPU_EXT_P_SIZE SZ_1M
> +#define VPU_EXT_D_SIZE SZ_4M
> +#define VPU_P_FW_SIZE (VPU_PTCM_SIZE + VPU_EXT_P_SIZE)
> +#define VPU_D_FW_SIZE (VPU_DTCM_SIZE + VPU_EXT_D_SIZE)
> +#define SHARE_BUF_SIZE 48
> +
> +#define VPU_P_FW "vpu_p.bin"
> +#define VPU_D_FW "vpu_d.bin"

These macros are of questionable value.

> +
> +#define VPU_BASE 0x0

Is this register really called "base" in the datasheet? From the use in
the code it looks like it performs a reset and/or PM function.

> +#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 memory information

Perhaps "VPU extended program/data memory information" instead.

> + *
> + * @p_va: the kernel virtual memory address of
> + * VPU extended program memory
> + * @d_va: the kernel virtual memory address of VPU extended data memory
> + * @p_iova: the iova memory address of VPU extended program memory
> + * @d_iova: the iova memory address of VPU extended data memory
> + */
> +struct vpu_mem {
> + void *p_va;
> + void *d_va;
> + dma_addr_t p_iova;
> + dma_addr_t d_iova;
> +};

Might be better as:

struct {
void *va;
dma_addr_t iova;
}

This can be then be used as: vpu->mem[P_FW].va . This doesn't matter
much yet but it would helps us common up some code later.

> +
> +/**
> + * struct vpu_regs - VPU SRAM and configuration registers
> + *
> + * @sram: the register for VPU sram
> + * @cfg: the register for VPU configuration
> + * @irq: the irq number for VPU interrupt
> + */
> +struct vpu_regs {
> + void __iomem *sram;

This is called TCM everywhere else. Why a different name for it here?

> + void __iomem *cfg;
> + int irq;
> +};
> +
> +/**
> + * struct vpu_run - VPU initialization status
> + *
> + * @signaled: the signal of vpu initialization completed
> + * @fw_ver: VPU firmware version
> + * @wq: wait queue for VPU initialization status
> + */
> +struct vpu_run {
> + u32 signaled;
> + char fw_ver[VPU_FW_VER_LEN];
> + 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 - The DTCM (Data Tightly-Coupled Memory) buffer shared with
> + * AP and VPU

Remove "The" (there are more than one of these buffers).

> + *
> + * @id: IPI id
> + * @len: share buffer length
> + * @share_buf: share buffer data
> + */
> +struct share_obj {
> + int32_t id;
> + uint32_t len;
> + unsigned char share_buf[SHARE_BUF_SIZE];
> +};
> +
> +/**
> + * struct mtk_vpu - vpu driver data
> + * @mem: VPU extended memory information
> + * @reg: VPU SRAM 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
> + * @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.
> + *
> + */
> +struct mtk_vpu {
> + struct vpu_mem mem;

Rename to extmem?

> + struct vpu_regs reg;
> + struct vpu_run run;
> + struct vpu_ipi_desc ipi_desc[IPI_MAX];
> + struct share_obj *recv_buf;
> + struct share_obj *send_buf;
> + struct device *dev;
> + struct clk *clk;
> + struct mutex vpu_mutex; /* for protecting vpu data data structure */
> +};
> +
> +/* the thread calls the function should hold the |vpu_mutex| */

Remove this comment. Its unhelpful: the code does not meet this
requirement because it overstates the scope of vpu_mutex .

> +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_BASE) & BIT(0);
> +}
> +
> +void vpu_disable_clock(struct platform_device *pdev)
> +{
> + struct mtk_vpu *vpu = platform_get_drvdata(pdev);
> +
> + /* Disable VPU watchdog */
> + vpu_cfg_writel(vpu,
> + vpu_cfg_readl(vpu, VPU_WDT_REG) & ~(1L<<31),
> + VPU_WDT_REG);

This code combines a reference counted clock disable with a
not-reference counted register write and will result in the watchdot
being spuriously disabled.

This will definitely happen if vpu_debug_read() is called at the wrong
time, possibly may also be an issue for concurrent H.264 and VP8 operations.

> +
> + clk_disable_unprepare(vpu->clk);
> +}
> +
> +int vpu_enable_clock(struct platform_device *pdev)
> +{
> + struct mtk_vpu *vpu = platform_get_drvdata(pdev);
> + int ret;
> +
> + ret = clk_prepare_enable(vpu->clk);
> + if (ret)
> + return ret;
> + /* Enable VPU watchdog */
> + vpu_cfg_writel(vpu, vpu_cfg_readl(vpu, VPU_WDT_REG) | (1L << 31),
> + VPU_WDT_REG);

As above.

> +
> + 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 < IPI_MAX && handler != NULL) {
> + 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 with invalid arguments\n");
> + return -EINVAL;
> +}

This API, and manu of its friends lower down the file, appear to be a
way to send 32 byte messages to different endpoints on another processor
on the SoC.

Just interested to know if you evaluated the mailbox driver
infrastructure for this? Its a good fit for the messaging but doesn't
offer any support for the direct access to TCM or extended memory.

> +int vpu_ipi_send(struct platform_device *pdev,
> + enum ipi_id id, void *buf,
> + unsigned int len, unsigned int wait)
> +{
> + struct mtk_vpu *vpu = platform_get_drvdata(pdev);
> + struct share_obj *send_obj = vpu->send_buf;
> + unsigned long timeout;
> +
> + if (id >= IPI_MAX || len > sizeof(send_obj->share_buf) || buf == NULL) {
> + dev_err(vpu->dev, "failed to send ipi message\n");
> + return -EINVAL;
> + }
> +
> + if (!vpu_running(vpu)) {
> + dev_err(vpu->dev, "vpu_ipi_send: VPU is not running\n");
> + return -ENXIO;
> + }
> +
> + mutex_lock(&vpu->vpu_mutex);
> + if (vpu_cfg_readl(vpu, HOST_TO_VPU) && !wait) {
> + mutex_unlock(&vpu->vpu_mutex);
> + return -EBUSY;
> + }

This branch is unreachable (no caller ever sets wait is never set to false).

> +
> + if (wait)
> + while (vpu_cfg_readl(vpu, HOST_TO_VPU))
> + ;

What is this loop for? This code should only be reachable if we timed
out in the code below so the likely effect of this loop is to
permantently wedge a thread in a manner that frustrates signal delivery.

> +
> + memcpy((void *)send_obj->share_buf, buf, len);
> + send_obj->len = len;
> + send_obj->id = id;
> + vpu_cfg_writel(vpu, 0x1, HOST_TO_VPU);
> +
> + /* Wait until VPU receives the 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");
> + return -EIO;
> + }
> + } while (vpu_cfg_readl(vpu, HOST_TO_VPU));

Do we need to busy wait every time we communicate with the co-processor?
Couldn't we put this wait *before* we write to HOST_TO_VPU above.

That way we only spin when there is a need to.

> +
> + mutex_unlock(&vpu->vpu_mutex);
> +
> + return 0;
> +}
> +
> +void *vpu_mapping_dm_addr(struct platform_device *pdev,
> + void *dtcm_dmem_addr)

Use a different type: dtcm_dmem_addr is not a pointer on this CPU.

> +{
> + struct mtk_vpu *vpu = platform_get_drvdata(pdev);
> + unsigned long p_vpu_dtcm = (unsigned long)VPU_DTCM(vpu);

p_vpu_dtcm *is* a pointer on this CPU. Why cast it so that it isn't.

> + unsigned long ul_dtcm_dmem_addr = (unsigned long)(dtcm_dmem_addr);
> +
> + if (dtcm_dmem_addr == NULL ||
> + (ul_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 (ul_dtcm_dmem_addr < VPU_DTCM_SIZE)
> + return (void *)(ul_dtcm_dmem_addr + p_vpu_dtcm);

Starting with the pointer will preserve type better:

return vpu->reg.sram + VPU_DTCM_OFFSET + ul_dtcm_dmem_addr;

> +
> + return (void *)((ul_dtcm_dmem_addr - VPU_DTCM_SIZE) +
> + VPU_DMEM0_VIRT(vpu));

Likewise this code is clearer with the pointer first.

return vpu->mem.d_va + (ul_dtcm_dmem_addr - VPU_DTCM_SIZE);

> +}
> +
> +dma_addr_t *vpu_mapping_iommu_dm_addr(struct platform_device *pdev,
> + void *dmem_addr)

This function does not return a pointer to a dma_addr_t. It just returns
a regular dma_addr_t (that's why all the callers of this function cast
it back ;-) ).

dmem_addr is also not a pointer and this function does not return a
pointer to a dma_addr_t. It just returns a regular dma_addr_t.

> +{
> + unsigned long ul_dmem_addr = (unsigned long)(dmem_addr);
> + struct mtk_vpu *vpu = platform_get_drvdata(pdev);
> +
> + if (dmem_addr == NULL ||
> + (ul_dmem_addr < VPU_DTCM_SIZE) ||
> + (ul_dmem_addr > (VPU_DTCM_SIZE + VPU_EXT_D_SIZE))) {
> + dev_err(vpu->dev, "invalid IOMMU data memory address\n");
> + return ERR_PTR(-EINVAL);
> + }
> +
> + return (dma_addr_t *)((ul_dmem_addr - VPU_DTCM_SIZE) +
> + VPU_DMEM0_IOVA(vpu));

Better written as (this would also have made explicit the type problem
with the function:

return vpu->mem.d_iova + (ul_dmem_addr - VPU_DTCM_SIZE);

> +}
> +
> +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, "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;
> +}

This function looks a bit weird to me. Why do we need to keep consulting
the devicetree every time we want to start/stop the clock?

I would have expected this code to be part of the init routine of
anything that needs this and the platform_device would then be cached.

> +
> +/* load vpu program/data memory */
> +static void load_requested_vpu(struct mtk_vpu *vpu,
> + size_t fw_size,
> + const u8 *fw_data,
> + u8 fw_type)
> +{
> + size_t target_size = fw_type ? VPU_DTCM_SIZE : VPU_PTCM_SIZE;
> + size_t extra_fw_size = 0;
> + void *dest;
> +
> + /* reset VPU */
> + vpu_cfg_writel(vpu, 0x0, VPU_BASE);
> +
> + /* handle extended firmware size */
> + if (fw_size > target_size) {
> + dev_dbg(vpu->dev, "fw size %lx > limited fw size %lx\n",
> + fw_size, target_size);
> + extra_fw_size = fw_size - target_size;
> + dev_dbg(vpu->dev, "extra_fw_size %lx\n", extra_fw_size);
> + fw_size = target_size;
> + }
> + dest = fw_type ? VPU_DTCM(vpu) : VPU_PTCM(vpu);
> + memcpy(dest, fw_data, fw_size);
> + /* download to extended memory if need */
> + if (extra_fw_size > 0) {
> + dest = fw_type ?
> + VPU_DMEM0_VIRT(vpu) : VPU_PMEM0_VIRT(vpu);
> +
> + dev_dbg(vpu->dev, "download extended memory type %x\n",
> + fw_type);
> + memcpy(dest, fw_data + target_size, extra_fw_size);
> + }
> +}
> +
> +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;
> + int ret;
> +
> + if (!pdev) {
> + dev_err(dev, "VPU platform device is invalid\n");
> + return -EINVAL;
> + }
> +
> + mutex_lock(&vpu->vpu_mutex);
> +
> + ret = vpu_enable_clock(pdev);
> + if (ret) {
> + dev_err(dev, "enable clock failed %d\n", ret);
> + goto OUT_LOAD_FW;
> + }
> +
> + if (vpu_running(vpu)) {
> + vpu_disable_clock(pdev);
> + mutex_unlock(&vpu->vpu_mutex);
> + dev_warn(dev, "vpu is running already\n");
> + return 0;
> + }
> +
> + run->signaled = false;
> + dev_dbg(vpu->dev, "firmware request\n");
> + ret = request_firmware(&vpu_fw, VPU_P_FW, dev);
> + if (ret < 0) {
> + dev_err(dev, "Failed to load %s, %d\n", VPU_P_FW, ret);
> + goto OUT_LOAD_FW;
> + }
> + if (vpu_fw->size > VPU_P_FW_SIZE) {
> + ret = -EFBIG;
> + dev_err(dev, "program fw size %zu is abnormal\n", vpu_fw->size);
> + goto OUT_LOAD_FW;
> + }

Possibly move request_firmware(), release_firmware() and the associated
error handling into load_requested_vpu(). It can all be parameterized
and the filename of the firmware means error reports will still be clear
about whether the p or d firmware is faulty.

> + dev_dbg(vpu->dev, "Downloaded program fw size: %zu.\n",
> + vpu_fw->size);
> + /* Downloading program firmware to device*/
> + load_requested_vpu(vpu, vpu_fw->size, vpu_fw->data,
> + P_FW);
> + release_firmware(vpu_fw);
> +
> + ret = request_firmware(&vpu_fw, VPU_D_FW, dev);
> + if (ret < 0) {
> + dev_err(dev, "Failed to load %s, %d\n", VPU_D_FW, ret);
> + goto OUT_LOAD_FW;
> + }
> + if (vpu_fw->size > VPU_D_FW_SIZE) {
> + ret = -EFBIG;
> + dev_err(dev, "data fw size %zu is abnormal\n", vpu_fw->size);
> + goto OUT_LOAD_FW;
> + }
> + dev_dbg(vpu->dev, "Downloaded data fw size: %zu.\n",
> + vpu_fw->size);
> + /* Downloading data firmware to device */
> + load_requested_vpu(vpu, vpu_fw->size, vpu_fw->data,
> + D_FW);
> + release_firmware(vpu_fw);
> + /* boot up vpu */
> + vpu_cfg_writel(vpu, 0x1, VPU_BASE);
> +
> + ret = wait_event_interruptible_timeout(run->wq,
> + run->signaled,
> + msecs_to_jiffies(INIT_TIMEOUT_MS)
> + );
> + if (0 == ret) {
> + 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:
> + vpu_disable_clock(pdev);
> + mutex_unlock(&vpu->vpu_mutex);
> +
> + return ret;
> +}
> +
> +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);
> + wake_up_interruptible(&vpu->run.wq);
> +}
> +
> +static int vpu_debug_open(struct inode *inode, struct file *file)
> +{
> + file->private_data = inode->i_private;
> + return 0;
> +}
> +
> +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 platform_device *pdev = to_platform_device(dev);
> + struct mtk_vpu *vpu = dev_get_drvdata(dev);
> +
> + ret = vpu_enable_clock(pdev);
> + 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_disable_clock(pdev);
> +
> + if (running) {
> + len = sprintf(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 = sprintf(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 = vpu_debug_open,
> + .read = vpu_debug_read,
> +};

These operations should be conditional on CONFIG_DEBUG_FS.

> +
> +static void vpu_free_p_ext_mem(struct mtk_vpu *vpu)
> +{
> + struct device *dev = vpu->dev;
> + struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
> +
> + dma_free_coherent(dev, VPU_EXT_P_SIZE, VPU_PMEM0_VIRT(vpu),
> + VPU_PMEM0_IOVA(vpu));
> +
> + if (domain)
> + iommu_detach_device(domain, vpu->dev);
> +}
> +
> +static void vpu_free_d_ext_mem(struct mtk_vpu *vpu)
> +{
> + struct device *dev = vpu->dev;
> + struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
> +
> + dma_free_coherent(dev, VPU_EXT_D_SIZE, VPU_DMEM0_VIRT(vpu),
> + VPU_DMEM0_IOVA(vpu));
> +
> + if (domain)
> + iommu_detach_device(domain, dev);
> +}

Look like this could be parameterized and combined with vpu_free_p_ext_mem.

> +
> +static int vpu_alloc_p_ext_mem(struct mtk_vpu *vpu)
> +{
> + struct device *dev = vpu->dev;
> + struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
> + phys_addr_t p_pa;
> +
> + VPU_PMEM0_VIRT(vpu) = dma_alloc_coherent(dev,
> + VPU_EXT_P_SIZE,
> + &(VPU_PMEM0_IOVA(vpu)),
> + GFP_KERNEL);
> + if (VPU_PMEM0_VIRT(vpu) == NULL) {
> + dev_err(dev, "Failed to allocate the extended program memory\n");
> + return PTR_ERR(VPU_PMEM0_VIRT(vpu));
> + }
> +
> + p_pa = iommu_iova_to_phys(domain, vpu->mem.p_iova);
> + /* Disable extend0. Enable extend1 */
> + vpu_cfg_writel(vpu, 0x1, VPU_PMEM_EXT0_ADDR);
> + vpu_cfg_writel(vpu, (p_pa & 0xFFFFF000), VPU_PMEM_EXT1_ADDR);
> +
> + dev_info(dev, "Program extend memory phy=0x%llx virt=0x%p iova=0x%llx\n",
> + (unsigned long long)p_pa,
> + VPU_PMEM0_VIRT(vpu),
> + (unsigned long long)VPU_PMEM0_IOVA(vpu));
> +
> + return 0;
> +}
> +
> +static int vpu_alloc_d_ext_mem(struct mtk_vpu *vpu)
> +{
> + struct device *dev = vpu->dev;
> + struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
> + phys_addr_t d_pa;
> +
> + VPU_DMEM0_VIRT(vpu) = dma_alloc_coherent(dev,
> + VPU_EXT_D_SIZE,
> + &(VPU_DMEM0_IOVA(vpu)),
> + GFP_KERNEL);
> + if (VPU_DMEM0_VIRT(vpu) == NULL) {
> + dev_err(dev, "Failed to allocate the extended data memory\n");
> + return PTR_ERR(VPU_DMEM0_VIRT(vpu));
> + }
> +
> + d_pa = iommu_iova_to_phys(domain, vpu->mem.d_iova);
> +
> + /* Disable extend0. Enable extend1 */
> + vpu_cfg_writel(vpu, 0x1, VPU_DMEM_EXT0_ADDR);
> + vpu_cfg_writel(vpu, (d_pa & 0xFFFFF000),
> + VPU_DMEM_EXT1_ADDR);
> +
> + dev_info(dev, "Data extend memory phy=0x%llx virt=0x%p iova=0x%llx\n",
> + (unsigned long long)d_pa,
> + VPU_DMEM0_VIRT(vpu),
> + (unsigned long long)VPU_DMEM0_IOVA(vpu));
> +
> + return 0;
> +}

Also looks suitable for parameterizing and combining with
vpu_alloc_p_ext_mem .

> +
> +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);
> + } 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 = (struct share_obj *)VPU_DTCM(vpu);
> + 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));
> + mutex_init(&vpu->vpu_mutex);
> +
> + return 0;
> +}
> +
> +static irqreturn_t vpu_irq_handler(int irq, void *priv)
> +{
> + struct mtk_vpu *vpu = priv;
> + uint32_t 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!\n");
> +
> + /* VPU won't send another interrupt until we set VPU_TO_HOST to 0. */
> + vpu_cfg_writel(vpu, 0x0, VPU_TO_HOST);

If we were triggered by a watchdog then how long will it be before the
next watchdog interrupt? Will we end up spamming the logs?
> +
> + return IRQ_HANDLED;
> +}
> +
> +static struct dentry *vpu_debugfs;
> +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, "sram");
> + vpu->reg.sram = devm_ioremap_resource(dev, res);
> + if (IS_ERR(vpu->reg.sram)) {
> + dev_err(dev, "devm_ioremap_resource vpu sram failed.\n");
> + return PTR_ERR(vpu->reg.sram);
> + }
> +
> + res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "cfg_reg");
> + vpu->reg.cfg = devm_ioremap_resource(dev, res);
> + if (IS_ERR(vpu->reg.cfg)) {
> + dev_err(dev, "devm_ioremap_resource vpu cfg failed.\n");
> + return PTR_ERR(vpu->reg.cfg);
> + }
> +
> + /* Get VPU clock */
> + vpu->clk = devm_clk_get(dev, "main");
> + if (vpu->clk == NULL) {
> + dev_err(dev, "get vpu clock fail\n");
> + return -EINVAL;
> + }
> +
> + platform_set_drvdata(pdev, vpu);
> +
> + ret = vpu_enable_clock(pdev);
> + if (ret) {
> + ret = -EINVAL;
> + return ret;

Why not just "return ret" (or "return -EINVAL")?

> + }
> +
> + 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;
> + }
> +
> + platform_set_drvdata(pdev, vpu);
> +
> + /* 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;
> + }
> +
> + vpu_debugfs = debugfs_create_file("mtk_vpu", S_IRUGO, NULL, (void *)dev,
> + &vpu_debug_fops);
> + if (!vpu_debugfs) {
> + ret = -ENOMEM;
> + goto cleanup_ipi;
> + }
> +
> + /* Set PTCM to 96K and DTCM to 32K */
> + vpu_cfg_writel(vpu, 0x2, VPU_TCM_CFG);
> +
> + ret = vpu_alloc_p_ext_mem(vpu);
> + if (ret) {
> + dev_err(dev, "Allocate PM failed\n");
> + goto remove_debugfs;
> + }
> +
> + ret = vpu_alloc_d_ext_mem(vpu);
> + if (ret) {
> + dev_err(dev, "Allocate DM failed\n");
> + goto free_p_mem;
> + }
> +
> + init_waitqueue_head(&vpu->run.wq);
> +
> + res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
> + if (res == NULL) {
> + dev_err(dev, "get IRQ resource failed.\n");
> + ret = -ENXIO;
> + goto free_d_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_d_mem;
> + }
> +
> + vpu_disable_clock(pdev);
> + dev_dbg(dev, "initialization completed\n");
> +
> + return 0;
> +
> +free_d_mem:
> + vpu_free_d_ext_mem(vpu);
> +free_p_mem:
> + vpu_free_p_ext_mem(vpu);
> +remove_debugfs:
> + debugfs_remove(vpu_debugfs);
> +cleanup_ipi:
> + memset(vpu->ipi_desc, 0, sizeof(struct vpu_ipi_desc)*IPI_MAX);
> +vpu_mutex_destroy:
> + mutex_destroy(&vpu->vpu_mutex);
> +disable_vpu_clk:
> + vpu_disable_clock(pdev);
> +
> + 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);
> +
> + vpu_free_p_ext_mem(vpu);
> + vpu_free_d_ext_mem(vpu);

This looks like it leaks cpu_debugfs and the vpu_mutex.

> +
> + return 0;
> +}
> +
> +static struct platform_driver mtk_vpu_driver = {
> + .probe = mtk_vpu_probe,
> + .remove = mtk_vpu_remove,
> + .driver = {
> + .name = MTK_VPU_DRV_NAME,
> + .owner = THIS_MODULE,
> + .of_match_table = mtk_vpu_match,
> + },
> +};
> +
> +module_platform_driver(mtk_vpu_driver);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_DESCRIPTION("Mediatek Video Prosessor Unit driver");
> diff --git a/drivers/media/platform/mtk-vpu/mtk_vpu_core.h b/drivers/media/platform/mtk-vpu/mtk_vpu_core.h
> new file mode 100644
> index 0000000..20cf2a0
> --- /dev/null
> +++ b/drivers/media/platform/mtk-vpu/mtk_vpu_core.h
> @@ -0,0 +1,161 @@
> +/*
> +* Copyright (c) 2015 MediaTek Inc.
> +* Author: Andrew-CT Chen <andrew-ct.chen@mediatek.com>
> +*
> +* 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_CORE_H
> +#define _MTK_VPU_CORE_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_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_VENC_CAPABILITY: The interrupt from vpu is to
> + get venc hardware capability.
> + * @IPI_MAX: The maximum IPI number
> + */
> +enum ipi_id {
> + IPI_VPU_INIT = 0,
> + IPI_VENC_H264,
> + IPI_VENC_VP8,
> + IPI_VENC_CAPABILITY,
> + IPI_MAX,
> +};
> +
> +/**
> + * vpu_disable_clock - Disable VPU clock
> + *
> + * @pdev: VPU platform device
> + *
> + *
> + * Return: Return 0 if the clock is disabled successfully,
> + * otherwise it is failed.
> + *
> + **/
> +void vpu_disable_clock(struct platform_device *pdev);
> +
> +/**
> + * vpu_enable_clock - Enable VPU clock
> + *
> + * @pdev: VPU platform device
> + *
> + * Return: Return 0 if the clock is enabled successfully,
> + * otherwise it is failed.
> + *
> + **/
> +int vpu_enable_clock(struct platform_device *pdev);
> +
> +/**
> + * 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
> + * @wait: wait for the last ipi completed.
> + *
> + * 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,
> + unsigned int wait);
> +
> +/**
> + * 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_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,
> + void *dtcm_dmem_addr);
> +
> +/**
> + * vpu_mapping_iommu_dm_addr - Mapping to iommu address
> + *
> + * @pdev: VPU platform device
> + * @dmem_addr: VPU's extended data memory address
> + *
> + * Mapping the VPU's extended data address to iommu address
> + *
> + * Return: Return ERR_PTR(-EINVAL) if mapping failed,
> + * otherwise the mapped iommu address
> + **/
> +dma_addr_t *vpu_mapping_iommu_dm_addr(struct platform_device *pdev,
> + void *dmem_addr);
> +#endif /* _MTK_VPU_CORE_H */
> diff --git a/drivers/media/platform/mtk-vpu/vp8_enc/venc_vp8_vpu.h b/drivers/media/platform/mtk-vpu/vp8_enc/venc_vp8_vpu.h
> new file mode 100644
> index 0000000..4e09eec
> --- /dev/null
> +++ b/drivers/media/platform/mtk-vpu/vp8_enc/venc_vp8_vpu.h

Like the H.264 header. Why is this file included in this patch? It is
not included by anything in the patch and defines symbols that do not
exist yet.

Daniel.