Subject: Re: [RFC PATCH V3 4/5] platform: mtk-isp: Add Mediatek DIP driver

From: Frederic Chen <[email-masked]>
Date: Thu, 12 Sep 2019 01:41:11 +0800

Hi Tomasz,

I appreciate your helpful comments.

On Tue, 2019-09-10 at 13:04 +0900, Tomasz Figa wrote:
> Hi Frederic,
> 
> On Tue, Sep 10, 2019 at 4:23 AM <[email-masked]> wrote:
> >
> > From: Frederic Chen <[email-masked]>
> >
> > This patch adds the driver of Digital Image Processing (DIP)
> > unit in Mediatek ISP system, providing image format
> > conversion, resizing, and rotation features.
> >
> > 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: Frederic Chen <[email-masked]>
> > ---
> >  drivers/media/platform/mtk-isp/Makefile       |    7 +
> >  .../media/platform/mtk-isp/isp_50/Makefile    |    7 +
> >  .../platform/mtk-isp/isp_50/dip/Makefile      |   18 +
> >  .../platform/mtk-isp/isp_50/dip/mtk_dip-dev.c |  650 +++++
> >  .../platform/mtk-isp/isp_50/dip/mtk_dip-dev.h |  566 +++++
> >  .../platform/mtk-isp/isp_50/dip/mtk_dip-hw.h  |  156 ++
> >  .../platform/mtk-isp/isp_50/dip/mtk_dip-sys.c |  521 ++++
> >  .../mtk-isp/isp_50/dip/mtk_dip-v4l2.c         | 2255 +++++++++++++++++
> >  8 files changed, 4180 insertions(+)
> >  create mode 100644 drivers/media/platform/mtk-isp/Makefile
> >  create mode 100644 drivers/media/platform/mtk-isp/isp_50/Makefile
> >  create mode 100644 drivers/media/platform/mtk-isp/isp_50/dip/Makefile
> >  create mode 100644 drivers/media/platform/mtk-isp/isp_50/dip/mtk_dip-dev.c
> >  create mode 100644 drivers/media/platform/mtk-isp/isp_50/dip/mtk_dip-dev.h
> >  create mode 100644 drivers/media/platform/mtk-isp/isp_50/dip/mtk_dip-hw.h
> >  create mode 100644 drivers/media/platform/mtk-isp/isp_50/dip/mtk_dip-sys.c
> >  create mode 100644 drivers/media/platform/mtk-isp/isp_50/dip/mtk_dip-v4l2.c
> >
> 
> Thanks for sending v3!
> 
> I'm going to do a full review a bit later, but please check one
> comment about power handling below.
> 
> Other than that one comment, from a quick look, I think we only have a
> number of style issues left. Thanks for the hard work!
> 
> [snip]
> > +static void dip_runner_func(struct work_struct *work)
> > +{
> > +       struct mtk_dip_request *req = mtk_dip_hw_mdp_work_to_req(work);
> > +       struct mtk_dip_dev *dip_dev = req->dip_pipe->dip_dev;
> > +       struct img_config *config_data =
> > +               (struct img_config *)req->working_buf->config_data.vaddr;
> > +
> > +       /*
> > +        * Call MDP/GCE API to do HW excecution
> > +        * Pass the framejob to MDP driver
> > +        */
> > +       pm_runtime_get_sync(dip_dev->dev);
> > +       mdp_cmdq_sendtask(dip_dev->mdp_pdev, config_data,
> > +                         &req->img_fparam.frameparam, NULL, false,
> > +                         dip_mdp_cb_func, req);
> > +}
> [snip]
> > +static void dip_composer_workfunc(struct work_struct *work)
> > +{
> > +       struct mtk_dip_request *req = mtk_dip_hw_fw_work_to_req(work);
> > +       struct mtk_dip_dev *dip_dev = req->dip_pipe->dip_dev;
> > +       struct img_ipi_param ipi_param;
> > +       struct mtk_dip_hw_subframe *buf;
> > +       int ret;
> > +
> > +       down(&dip_dev->sem);
> > +
> > +       buf = mtk_dip_hw_working_buf_alloc(req->dip_pipe->dip_dev);
> > +       if (!buf) {
> > +               dev_err(req->dip_pipe->dip_dev->dev,
> > +                       "%s:%s:req(%p): no free working buffer available\n",
> > +                       __func__, req->dip_pipe->desc->name, req);
> > +       }
> > +
> > +       req->working_buf = buf;
> > +       mtk_dip_wbuf_to_ipi_img_addr(&req->img_fparam.frameparam.subfrm_data,
> > +                                    &buf->buffer);
> > +       memset(buf->buffer.vaddr, 0, DIP_SUB_FRM_SZ);
> > +       mtk_dip_wbuf_to_ipi_img_sw_addr(&req->img_fparam.frameparam.config_data,
> > +                                       &buf->config_data);
> > +       memset(buf->config_data.vaddr, 0, DIP_COMP_SZ);
> > +
> > +       if (!req->img_fparam.frameparam.tuning_data.present) {
> > +               /*
> > +                * When user enqueued without tuning buffer,
> > +                * it would use driver internal buffer.
> > +                */
> > +               dev_dbg(dip_dev->dev,
> > +                       "%s: frame_no(%d) has no tuning_data\n",
> > +                       __func__, req->img_fparam.frameparam.frame_no);
> > +
> > +               mtk_dip_wbuf_to_ipi_tuning_addr
> > +                               (&req->img_fparam.frameparam.tuning_data,
> > +                                &buf->tuning_buf);
> > +               memset(buf->tuning_buf.vaddr, 0, DIP_TUNING_SZ);
> > +       }
> > +
> > +       mtk_dip_wbuf_to_ipi_img_sw_addr(&req->img_fparam.frameparam.self_data,
> > +                                       &buf->frameparam);
> > +       memcpy(buf->frameparam.vaddr, &req->img_fparam.frameparam,
> > +              sizeof(req->img_fparam.frameparam));
> > +       ipi_param.usage = IMG_IPI_FRAME;
> > +       ipi_param.frm_param.handle = req->id;
> > +       ipi_param.frm_param.scp_addr = (u32)buf->frameparam.scp_daddr;
> > +
> > +       mutex_lock(&dip_dev->hw_op_lock);
> > +       atomic_inc(&dip_dev->num_composing);
> > +       ret = scp_ipi_send(dip_dev->scp_pdev, SCP_IPI_DIP, &ipi_param,
> > +                          sizeof(ipi_param), 0);
> 
> We're not holding the pm_runtime enable count here
> (pm_runtime_get_sync() wasn't called), so rproc_shutdown() might have
> been called. Wouldn't that affect the ability for this IPI to run?
> 
> We had a related discussion with Jerry on the FD series and I think
> the conclusion is:
> a) if there is any state that needs to be preserved between jobs, that
> would be cleared by rproc_shutdown() then we need to call
> rproc_boot/shutdown() when we start/stop streaming.
> b) it there is no such state, we can keep them inside runtime PM
> callbacks, but we need to call pm_runtime_get_sync() before sending an
> IPI and pm_runtime_mark_last_busy() + pm_runtime_put_autosuspend()
> after the SCP signals completion. In this case the runtime PM
> autosuspend delay should be set to around 2-3 times the delay needed
> for rproc_shutdown() + rproc_boot() to complete.

Since each IMG_IPI_FRAME command is stateless, I would like to
use pm_runtime_get_sync()/ pm_runtime_mark_last_busy()/
pm_runtime_put_autosuspend() to fix this issue (solution b).

> Best regards,
> Tomasz

Sincerely,

Frederic Chen

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