[PATCH 14/45] dm: blk: Add udevice functions

[Simon Glass]

Hi Takahiro,

On Wed, 28 Sept 2022 at 18:51, AKASHI Takahiro
<takahiro.akashi at linaro.org> wrote:
>
> Hi Simon,
>
> On Wed, Sep 28, 2022 at 04:20:56AM -0600, Simon Glass wrote:
> > Hi Takahiro,
> >
> > On Sun, 25 Sept 2022 at 18:17, AKASHI Takahiro
> > <takahiro.akashi at linaro.org> wrote:
> > >
> > > Hi Simon,
> > >
> > > On Sun, Sep 25, 2022 at 09:02:17AM -0600, Simon Glass wrote:
> > > > At present we have functions called blk_dread(), etc., which take a
> > > > struct blk_desc * to refer to the block device. Add some functions which
> > > > use udevice instead, since this is more in keeping with how driver model
> > > > is supposed to work.
> > >
> > > Unfortunately, NAK.
> > > I have already added similar functions in disk/disk-uclass.c
> > > with my commit 59da9d4782cd ("dm: disk: add read/write interfaces with
> > > udevice"). dev_read()/dev_write() works well with UCLASS_BLK (as intended).
> > >
> > > I remember that you also ack'ed that patch.
> >
> > You have a better memory than me!
> >
> > How about we make those functions call my new ones?
>
> So do you want to have two distinct API's for BLK and PARTITION?
> You seem to have a policy that each DM class should have its own
> API's.

Yes that's right.

>
> I don't have a strong opinion here, but form user's point of view,
> block-level accessing has no difference between BLK and PARTITION.
> Most common users of such accessors are file systems.
> In stead of using the following code at every corner,
>    cid = device_get_uclass_id(udev);
>    if (cid == UCLASS_BLK)
>        blk_read(udev, ...);
>    else if (cid == UCLASS_PARTITION)
>        disk_part(udev, ...);
> it may be more convenient to have a single API.

Yes I agree, but you already have that with your dev_read() API. I
just want to rename it a bit.

>
> > Also I think we should rename your functions to avoid using the
> > dev_read prefix, since this is for reading from the device tree.
>
> Okay.
>
> > Perhaps disk_read()? Also it seems that we could rationalise the code
> > between disk_read() and part_read() ?
>
> I'm not sure what you mean by "rationalise".

The code seems to be almost the same between the two so I think it may
be possible to move the common code into a shared function.

>
> > Also should have comments in the
> > header file about what the functions do (and what type of device they
> > accept).
>
> Yeah.

Regards,
Simon