Re: [RFC PATCH V0 7/7] [media] platform: mtk-isp: Add Mediatek ISP Pass 1 driver

Tomasz Figa
2019-02-19T08:51:40Z

Hi Jungo,

On Sun, Feb 17, 2019 at 11:56 AM Jungo Lin <jungo.lin@mediatek.com> wrote:
>
> On Wed, 2019-02-13 at 18:50 +0900, Tomasz Figa wrote:
> > (() . ( strHi Frederic, Jungo,
> >
> > On Tue, Feb 5, 2019 at 3:43 PM Frederic Chen <frederic.chen@mediatek.com> wrote:
> > >
> > > From: Jungo Lin <jungo.lin@mediatek.com>
> > >
> > > This patch adds the driver for Pass unit in Mediatek's camera
> > > ISP system. Pass 1 unit is embedded in Mediatek SOCs. It
> > > provides RAW processing which includes optical black correction,
> > > defect pixel correction, W/IR imbalance correction and lens
> > > shading correction.
> > >
> > > The mtk-isp directory will contain drivers for multiple IP
> > > blocks found in Mediatek ISP system. It will include ISP Pass 1
> > > driver, sensor interface driver, DIP driver and face detection
> > > driver.
> >
> > Thanks for the patches! Please see my comments inline.
> >
>
> Dear Thomas:
>
> Thanks for your comments.
>
> We will revise the source codes based on your comments.
> Since there are many comments to fix/revise, we will categorize &
> prioritize these with below list:
>
> 1. Coding style issues.
> 2. Coding defects, including unused codes.
> 3. Driver architecture refactoring, such as removing mtk_cam_ctx,
> unnecessary abstraction layer, etc.
>

Thanks for replying to the comments!

Just to clarify, there is no need to hurry with resending a next patch
set with only a subset of the changes. Please take your time to
address all the comments before sending the next revision. This
prevents forgetting about some remaining comments and also lets other
reviewers come with new comments or some alternative ideas for already
existing comments. Second part of my review is coming too.

P.S. Please avoid top-posting on mailing lists. If replying to a
message, please reply below the related part of that message. (I've
moved your reply to the place in the email where it should be.)

[snip]
> > > + phys_addr_t paddr;
> >
> > We shouldn't need physical address either. I suppose this is for the
> > SCP, but then it should be a DMA address obtained from dma_map_*()
> > with struct device pointer of the SCP.
> >
>
> Yes, this physical address is designed for SCP.
> For tuning buffer, it will be touched by SCP and
> SCP can't get the physical address by itself. So we need to get
> this physical address in the kernel space via mtk_cam_smem_iova_to_phys
> function call and pass it to the SCP. At the same time, DMA address
> (daddr) is used for ISP HW.
>

Right, but my point is that in the kernel phys_addr_t is the physical
address from the CPU point of view. Any address from device point of
view is dma_addr_t and should be obtained from the DMA mapping API
(even if it's numerically the same as physical address).

Best regards,
Tomasz