[U-Boot] [linux-sunxi] Re: [PATCH v3 0/9] mmc: sunxi: Enable DM_MMC

[Chen-Yu Tsai]

On Fri, Jan 25, 2019 at 7:37 PM Andre Przywara <andre.przywara at arm.com> wrote:
>
> On Fri, 25 Jan 2019 19:01:12 +0800
> Chen-Yu Tsai <wens at csie.org> wrote:
>
> Hi,
>
> > On Fri, Jan 25, 2019 at 6:41 PM Jagan Teki
> > <jagan at amarulasolutions.com> wrote:
> > >
> > > On Fri, Jan 25, 2019 at 2:05 PM Chen-Yu Tsai <wens at csie.org>
> > > wrote:
> > > >
> > > > On Fri, Jan 25, 2019 at 4:27 PM Jagan Teki
> > > > <jagan at amarulasolutions.com> wrote:
> > > > >
> > > > > On Tue, Jan 22, 2019 at 7:55 AM Chen-Yu Tsai <wens at csie.org>
> > > > > wrote:
> > > > > >
> > > > > > On Mon, Jan 21, 2019 at 6:31 PM Jagan Teki
> > > > > > <jagan at amarulasolutions.com> wrote:
> > > > > > >
> > > > > > > Compared to previous version changes[1] this version do
> > > > > > > manage ahb clocks/resets via CLK framework.
> > > > > > >
> > > > > > > This version created changes along with Andre patches to
> > > > > > > support clock/resets[2]
> > > > > > >
> > > > > > > Tested A64, SD, eMMC and respective changes available at
> > > > > > > u-boot-sunxi/next
> > > > > > >
> > > > > > > Changes for v3:
> > > > > > > - Handle clock via CLK framework.
> > > > > > > Changes for v2:
> > > > > > > - update the 'reset enablement' logic to do
> > > > > > >   required SoC's
> > > > > > >
> > > > > > > [1] https://patchwork.ozlabs.org/cover/1026828/
> > > > > > > [2] https://patchwork.ozlabs.org/cover/1027850/
> > > > > > >
> > > > > > > Andre Przywara (2):
> > > > > > >   sunxi: clk: add MMC gates/resets
> > > > > > >   sunxi: clk: A80: add MMC clock support
> > > > > > >
> > > > > > > Jagan Teki (7):
> > > > > > >   mmc: sunxi: Add A83T emmc compatible
> > > > > > >   mmc: sunxi: Add mmc, emmc H5/A64 compatible
> > > > > > >   mmc: sunxi: Add DM_MMC support for H6
> > > > > > >   mmc: sunxi: Add DM_MMC support for A80
> > > > > > >   dm: mmc: sunxi: Add CLK and RESET support
> > > > > > >   arm: sunxi: Enable DM_MMC
> > > > > > >   arm: dts: sunxi: Enumerate MMC2 as MMC1
> > > > > >
> > > > > > Tested-by: Chen-Yu Tsai <wens at csie.org> # on the Bananapi M2M
> > > > > >
> > > > > > However, the A80 MMC clock patch is still missing code to
> > > > > > toggle the upstream bus clock gate and reset control in the
> > > > > > CCU.
> > > > >
> > > > > Sent it with original mmc clock and reset patch[1], let me know
> > > > > your comments.
> > > >
> > > > Right. The problem is nowhere in this series are those enabled /
> > > > deasserted. The A80 CCU only has one gate & reset for the whole
> > > > MMC subsystem, including the MMC config clocks block. Ideally the
> > > > driver for that block should enable the gate and deassert the
> > > > reset control.
> > >
> > > Yes, that same has been included with v3.1 patch which I linked
> > > above.
> >
> > The gates/resets are added in that patch. No one is using them. The
> > device tree node for the MMC controllers do _not_ reference this clock
> > and reset, only the individual ones in the MMC config clock block.
> >
> > Unless you are expecting BROM or SPL to have set that up for you,
> > which IMO is quite fragile. You could very well boot from SPI or even
> > FEL, and it wouldn't be correctly setup, in which case MMC would be
> > completely broken.
> >
> > FYI the clk-sun9i-mmc driver in Linux deasserts the reset at probe:
> >
> >     https://elixir.bootlin.com/linux/latest/source/drivers/clk/sunxi/clk-sun9i-mmc.c#L145
> >
> > And enables the bus gate when it needs to toggle bits in its register
> > space:
> >
> >     https://elixir.bootlin.com/linux/latest/source/drivers/clk/sunxi/clk-sun9i-mmc.c#L53
> >
> > This is what is missing. Andre's patch doesn't have them. He
> > specifically mentioned this.
>
> But this is addressed by this, isn't it?
> https://lists.denx.de/pipermail/u-boot/2019-January/355856.html
> (combined with Jagan's addition of the shared gates in v3.1)

Yes it does, however nowhere is it mentioned in the cover letter.
That and I managed to purge it from my short term memory.

So with the two series combined it should work properly on the A80.

BTW, Jagan, vN.M patches are very hard to track...

ChenYu

> Btw.: Somehow I managed to send it from the wrong branch (doesn't even
> compile), will send a fix later.
>
> Jagan, we need this patch for A80, and also the pinmux setup patch (1/2
> in this series) for it to work. That together with the H3 reset hiccup
> should be enough to justify a v4, I believe. Also I had some comments
> on your v3 (commit messages outdated, 7/9 too complicated), are you
> going to address them?
>
> Meanwhile I prepared a branch to have everything we need:
> https://github.com/apritzel/u-boot/commits/sunxi-dm-gates
> Please ignore the top 4 commits for now (adding SPI flash support).
>
> Cheers,
> Andre.