[U-Boot] [PATCH] dwmmc: make driver usable for non-exynos platforms

[Alexey Brodkin]

Hi Jaehoon,

On Fri, 2013-11-29 at 12:46 +0900, Jaehoon Chung wrote:
> Hi, Alexey,
> 
> I didn't know exactly which version is used this register.
> I known this register is used only the exynos series.
> I have checked the IP version 2.70a, but CLKSEL(0x9c) wasn't used at general register map.
> 
> If I missed the something, let me know.(It's published the upper IP version than 2.70a)
> 
The main point of my patch was to remove "#include <asm/arch/dwmmc.h>"
from "dwmmc.c".

I think it's pretty clear that if any particular device driver is
implemented not in your "board" folder but in common "drivers" folder it
is sort of expected to be independent from architecture/platform, right?

And for simplicity I copy-pasted all defines from
"arch/arm/include/asm/arch-exynos/dwmmc.h" to common "include/dwmmc.h".

Which was a bit too recklessly from my side - I should have spend so
more time and come up with more accurate solution which I will do now
with v2 re-spin.

As for DWMCI_CLKSEL.
I checked the same version of databook for DesignWare Mobile Storage and
do see there a register with offset = 0x9c.

This is:
========
DSCADDRU (For 64-bit Address Configuration Only)
Name: Current Host Descriptor Address Upper Register
========

I may understand that your current DW MMC is configured to use 32-bit
addresses, right?
Because of this you selected this offset "0x9c" and experience no
problems. But at some point you may get HW configured to use 64-bit
addressing and you'll need to use another offset for Exynos-specific
things. I understand that as SW engineer you have not much things to do
here but would be good if you communicate this to HW engineers.

And indeed this one could be left untouched in
"asm/arch-exynos/dwmmc.h".

Also I may see following defines aren't used anywhere in existing
(today's "master" branch) U-Boot sources:
========
#define DWMCI_SHIFT_0		0x0
#define DWMCI_SHIFT_1		0x1
#define DWMCI_SHIFT_2		0x2
#define DWMCI_SHIFT_3		0x3
========
So these might be dumped at all.

Regards,
Alexey