Re: [PATCH v7 2/8] [media] VPU: mediatek: support Mediatek VPU

andrew-ct chen
2016-04-25T09:22:10Z

On Mon, 2016-04-25 at 09:40 +0200, Hans Verkuil wrote:
> On 04/22/2016 06:25 AM, 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>
> > Signed-off-by: Tiffany Lin <tiffany.lin@mediatek.com>
> >
> > ---
> > drivers/media/platform/Kconfig | 13 +
> > drivers/media/platform/Makefile | 2 +
> > drivers/media/platform/mtk-vpu/Makefile | 3 +
> > drivers/media/platform/mtk-vpu/mtk_vpu.c | 950 ++++++++++++++++++++++++++++++
> > drivers/media/platform/mtk-vpu/mtk_vpu.h | 162 +++++
> > 5 files changed, 1130 insertions(+)
> > create mode 100644 drivers/media/platform/mtk-vpu/Makefile
> > create mode 100755 drivers/media/platform/mtk-vpu/mtk_vpu.c
> > create mode 100644 drivers/media/platform/mtk-vpu/mtk_vpu.h
> >
>
>
> > +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;
> > + }
> > +
> > + ret = vpu_clock_enable(vpu);
> > + if (ret) {
> > + dev_err(dev, "enable clock failed %d\n", ret);
> > + return ret;
> > + }
> > +
> > + mutex_lock(&vpu->vpu_mutex);
> > +
> > + if (vpu_running(vpu)) {
> > + mutex_unlock(&vpu->vpu_mutex);
> > + vpu_clock_disable(vpu);
> > + dev_warn(dev, "vpu is running already\n");
>
> This warning should be dropped. Currently vpu_load_firmware is called
> every time the video device is opened and no one else has the video device
> open. So calling this multiple times is perfectly normal and the log shouldn't
> be spammed with warnings.
>
> I would recommend adding a fw_loaded bool to struct mtk_vpu and just
> check that at the beginning of this function and just return 0 if it is true.
>
> Then you don't need to enable the vpu clock either.
>
> I hope I understand the hw correctly, though.
>
> Assuming you can do this, then this code from the v4l driver needs an
> additional comment:

We will change this in next version.

>
> >>> + if (v4l2_fh_is_singular(&ctx->fh)) {
>
> Add a comment here that says that vpu_load_firmware checks if it was
> loaded already and does nothing in that case.

We will change this in next version. Thanks

>
> >>> + ret = vpu_load_firmware(dev->vpu_plat_dev);
> >>> + if (ret < 0) {
> >>> + /*
> >>> + * Return 0 if downloading firmware successfully,
> >>> + * otherwise it is failed
> >>> + */
> >>> + mtk_v4l2_err("vpu_load_firmware failed!");
> >>> + goto err_load_fw;
> >>> + }
>
> That makes it clear to the reader (i.e. me :-) ) that you can safely call
> vpu_load_firmware multiple times.
>
> Regards,
>
> Hans
>
> > + return 0;
> > + }
> > +
> > + 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;
> > + }
> > +
> > + /* 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);
>