Re: [RFC PATCH V2 4/4] platform: mtk-isp: Add Mediatek FD driver

[Tomasz Figa <tfiga-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>]

On Wed, Aug 28, 2019 at 11:00 AM Jerry-ch Chen
<Jerry-ch.Chen-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org> wrote:
>
> Hi Tomasz,
>
> On Mon, 2019-08-26 at 14:36 +0800, Tomasz Figa wrote:
> > Hi Jerry,
> >
> > On Sun, Aug 25, 2019 at 6:18 PM Jerry-ch Chen
> > <Jerry-ch.Chen-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org> wrote:
> > >
> > > Hi Tomasz,
> > >
> > > On Fri, 2019-08-02 at 16:28 +0800, Tomasz Figa wrote:
> > > > Hi Jerry,
> > > >
> > > > On Tue, Jul 09, 2019 at 04:41:12PM +0800, Jerry-ch Chen wrote:
> > > > > From: Jerry-ch Chen <jerry-ch.chen-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
> > > > >
> > > > > This patch adds the driver of Face Detection (FD) unit in
> > > > > Mediatek camera system, providing face detection function.
> > > > >
> > > > > The mtk-isp directory will contain drivers for multiple IP
> > > > > blocks found in Mediatek ISP system. It will include ISP Pass 1
> > > > > driver (CAM), sensor interface driver, DIP driver and face
> > > > > detection driver.
> > > > >
> > > > > Signed-off-by: Jerry-ch Chen <jerry-ch.chen-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
> > > > > ---
> > > > >  drivers/media/platform/Makefile               |    2 +
> > > > >  drivers/media/platform/mtk-isp/fd/Makefile    |    5 +
> > > > >  drivers/media/platform/mtk-isp/fd/mtk_fd.h    |  157 +++
> > > > >  drivers/media/platform/mtk-isp/fd/mtk_fd_40.c | 1259 +++++++++++++++++++++++++
> > > > >  include/uapi/linux/v4l2-controls.h            |    4 +
> > > > >  5 files changed, 1427 insertions(+)
> > > > >  create mode 100644 drivers/media/platform/mtk-isp/fd/Makefile
> > > > >  create mode 100644 drivers/media/platform/mtk-isp/fd/mtk_fd.h
> > > > >  create mode 100644 drivers/media/platform/mtk-isp/fd/mtk_fd_40.c
> > > > >
> > > >
> > > > Thanks for the patch! I finally got a chance to fully review the code. Sorry
> > > > for the delay. Please check my comments inline.
> > > >
> > > I appreciate your comments.
> > > I've fixed most of the comments and verifying them,
> > > Sorry for the delay, here is the reply.
> > >
> >
> > Thanks for replying to all the comments, it's very helpful. I'll snip
> > the parts that I don't have any further comments.
> >
> > [snip]
> >
> > > > > +   if (usercount == 1) {
> > > > > +           pm_runtime_get_sync(&fd_dev->pdev->dev);
> > > > > +           if (mtk_fd_hw_enable(fd_hw)) {
> > > > > +                   pm_runtime_put_sync(&fd_dev->pdev->dev);
> > > > > +                   atomic_dec_return(&fd_hw->fd_user_cnt);
> > > > > +                   mutex_unlock(&fd_hw->fd_hw_lock);
> > > > > +                   return -EINVAL;
> > > > > +           }
> > > > > +   }
> > > >
> > > > This is a simple mem-to-mem device, so there is no reason to keep it active
> > > > all the time it's streaming. Please just get the runtime PM counter when
> > > > queuing a job to the hardware and release it when the job finishes.
> > > >
> > > > I guess we might still want to do the costly operations like rproc_boot()
> > > > when we start streaming, though.
> > > >
> > > Do you mean by moving the pm_runtime_get/put stuff to the job execution
> > > and job finish place?
> >
> > Yes.
> >
> > > the rproc_boot() operation will be done here.
> > >
> >
> > How much time does the rproc_boot() operation take?
> >
>
> About 0.7~1.3ms, average 0.8ms (14 measurements)
>

Okay, I think we may want to call it when we start streaming then.

[snip]

> > > > > +static int mtk_fd_vb2_queue_setup(struct vb2_queue *vq,
> > > > > +                             unsigned int *num_buffers,
> > > > > +                             unsigned int *num_planes,
> > > > > +                             unsigned int sizes[],
> > > > > +                             struct device *alloc_devs[])
> > > > > +{
> > > > > +   struct mtk_fd_ctx *ctx = vb2_get_drv_priv(vq);
> > > > > +   struct device *dev = ctx->dev;
> > > > > +   unsigned int size;
> > > > > +
> > > > > +   switch (vq->type) {
> > > > > +   case V4L2_BUF_TYPE_META_CAPTURE:
> > > > > +           size = ctx->dst_fmt.buffersize;
> > > > > +           break;
> > > > > +   case V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE:
> > > > > +           size = ctx->src_fmt.plane_fmt[0].sizeimage;
> > > > > +           break;
> > > > > +   default:
> > > > > +           dev_err(dev, "invalid queue type: %d\n", vq->type);
> > > >
> > > > We should need to handle this.
> > > >
> > > Do you mean by giving a size instead of return -EINVAL?
> > >
> >
> > Sorry, typo. I meant we shouldn't need to handle it, because we can't
> > get any other queue type here.
> >
>
> Ok, I see, I will remove it.
> also, this function will be updated as following due to the 2 plane
> case.
>
> static int mtk_fd_vb2_queue_setup(struct vb2_queue *vq,
>                                   unsigned int *num_buffers,
>                                   unsigned int *num_planes,
>                                   unsigned int sizes[],
>                                   struct device *alloc_devs[])
> {
>         struct mtk_fd_ctx *ctx = vb2_get_drv_priv(vq);
>         struct device *dev = ctx->dev;
>         unsigned int size[2];
>
>         switch (vq->type) {
>         case V4L2_BUF_TYPE_META_CAPTURE:
>                 size[0] = ctx->dst_fmt.buffersize;
>                 break;
>         case V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE:
>                 size[0] = ctx->src_fmt.plane_fmt[0].sizeimage;
>                 if (*num_planes == 2)
>                         size[1] = ctx->src_fmt.plane_fmt[1].sizeimage;
>                 break;
>         }
>
>         if (*num_planes == 1) {
>                 if (sizes[0] < size[0])
>                         return -EINVAL;
>         } else if (*num_planes == 2) {
>                 if ((sizes[0] < size[0]) && (sizes[1] < size[1]))
>                         return -EINVAL;

Can we just use a loop here and combine the 2 cases above?

Also, we need to fail with -EINVAL if *num_planes is > 2.

>         } else {
>                 *num_planes = 1;
>                 sizes[0] = size[0];

This should be the case if *num_planes == 0 and the number of planes
and sizes should match the currently active format.

>         }
>
>         return 0;
> }
>
> > [snip]
> >
> > > > > +static void mtk_fd_vb2_stop_streaming(struct vb2_queue *vq)
> > > > > +{
> > > > > +   struct mtk_fd_ctx *ctx = vb2_get_drv_priv(vq);
> > > > > +   struct vb2_buffer *vb;
> > > >
> > > > How do we guarantee here that the hardware isn't still accessing the buffers
> > > > removed below?
> > > >
> > > Maybe we can check the driver state flag and aborting the unfinished
> > > jobs?
> > > (fd_hw->state == FD_ENQ)
> > >
> >
> > Yes, we need to either cancel or wait for the currently processing
> > job. It depends on hardware capabilities, but cancelling is generally
> > preferred for the lower latency.
> >
> Ok, it the state is ENQ, then we can disable the FD hw by controlling
> the registers.
>
> for example:
>         writel(0x0, fd->fd_base + FD_HW_ENABLE);
>         writel(0x0, fd->fd_base + FD_INT_EN);
>

What's exactly the effect of writing 0 to FD_HW_ENABLE?

[snip]

> > > > > +}
> > > > > +
> > > > > +static void mtk_fd_vb2_request_complete(struct vb2_buffer *vb)
> > > > > +{
> > > > > +   struct mtk_fd_ctx *ctx = vb2_get_drv_priv(vb->vb2_queue);
> > > > > +
> > > > > +   v4l2_ctrl_request_complete(vb->req_obj.req, &ctx->hdl);
> > > > > +}
> > > > > +
> > > > > +static void mtk_fd_fill_pixfmt_mp(struct v4l2_pix_format_mplane *dfmt,
> > > > > +                             const struct v4l2_pix_format_mplane *sfmt)
> > > > > +{
> > > > > +   dfmt->width = sfmt->width;
> > > > > +   dfmt->height = sfmt->height;
> > > > > +   dfmt->pixelformat = sfmt->pixelformat;
> > > > > +   dfmt->field = sfmt->field;
> > > > > +   dfmt->colorspace = sfmt->colorspace;
> > > > > +   dfmt->num_planes = sfmt->num_planes;
> > > > > +
> > > > > +   /* Use default */
> > > > > +   dfmt->ycbcr_enc = V4L2_YCBCR_ENC_DEFAULT;
> > > > > +   dfmt->quantization = V4L2_QUANTIZATION_DEFAULT;
> > > > > +   dfmt->xfer_func =
> > > > > +           V4L2_MAP_XFER_FUNC_DEFAULT(dfmt->colorspace);
> > > > > +   dfmt->plane_fmt[0].bytesperline = dfmt->width * 2;
> > > > > +   dfmt->plane_fmt[0].sizeimage =
> > > > > +           dfmt->height * dfmt->plane_fmt[0].bytesperline;
> > > > > +   memset(dfmt->reserved, 0, sizeof(dfmt->reserved));
> > > > > +}
> > > >
> > > > Could we unify this function with mtk_fd_m2m_try_fmt_out_mp()? That function
> > > > should be almost directly reusable for the default format initialization +/-
> > > > the arguments passed to it.
> > > >
> > > Ok, I will try to reuse it as following:
> > >
> > > static void mtk_fd_fill_pixfmt_mp(struct v4l2_pix_format_mplane *dfmt,
> > >   const struct v4l2_pix_format_mplane *sfmt)
> > > {
> > > dfmt->field = V4L2_FIELD_NONE;
> > > dfmt->colorspace = V4L2_COLORSPACE_BT2020;
> > > dfmt->num_planes = sfmt->num_planes;
> > > dfmt->ycbcr_enc = V4L2_YCBCR_ENC_DEFAULT;
> > > dfmt->quantization = V4L2_QUANTIZATION_DEFAULT;
> > > dfmt->xfer_func =
> > > V4L2_MAP_XFER_FUNC_DEFAULT(dfmt->colorspace);
> > >
> > > /* Keep user setting as possible */
> > > dfmt->width = clamp(dfmt->width,
> > >     MTK_FD_OUTPUT_MIN_WIDTH,
> > >     MTK_FD_OUTPUT_MAX_WIDTH);
> > > dfmt->height = clamp(dfmt->height,
> > >      MTK_FD_OUTPUT_MIN_HEIGHT,
> > >      MTK_FD_OUTPUT_MAX_HEIGHT);
> > >
> > > if (sfmt->num_planes == 2) {
> > > /* NV16M and NV61M has 1 byte per pixel */
> > > dfmt->plane_fmt[0].bytesperline = dfmt->width;
> > > dfmt->plane_fmt[1].bytesperline = dfmt->width;
> > > } else {
> > > /* 2 bytes per pixel */
> > > dfmt->plane_fmt[0].bytesperline = dfmt->width * 2;
> > > }
> > >
> > > dfmt->plane_fmt[0].sizeimage =
> > > dfmt->height * dfmt->plane_fmt[0].bytesperline;
> > > }
> >
> > How would the implementation of TRY_FMT look in this case?
> >
>
> It will be looked like:
>
> static int mtk_fd_try_fmt_out_mp(struct file *file,
>                                      void *fh,
>                                      struct v4l2_format *f)
> {
>         struct v4l2_pix_format_mplane *pix_mp = &f->fmt.pix_mp;
>         const struct v4l2_pix_format_mplane *fmt;
>
>         fmt = mtk_fd_find_fmt(pix_mp->pixelformat);
>         if (!fmt)
>                 fmt = &mtk_fd_img_fmts[0];      /* Get default img fmt */
>
>         mtk_fd_fill_pixfmt_mp(pix_mp, fmt);
>         return 0;
> }
>

Okay, thanks!

Best regards,
Tomasz