[U-Boot] [PATCH 1/5] mmc: sunxi: add support for automatic delay calibration

[Andre Przywara]

On Mon, 1 Oct 2018 10:09:55 +0200
Maxime Ripard <maxime.ripard at bootlin.com> wrote:

> On Sun, Sep 30, 2018 at 04:16:36PM +0100, André Przywara wrote:
> > On 9/30/18 12:45 AM, Vagrant Cascadian wrote:  
> > > From: Vasily Khoruzhick <anarsoul at gmail.com>
> > > 
> > > A64 supports automatic delay calibration and Linux driver uses it
> > > instead of hardcoded delays. Add support for it to u-boot
> > > driver.  
> > 
> > So technically that should be derived from the node's compatible
> > string, like we do in Linux. But I see that we are not there yet in
> > U-Boot. Meanwhile I don't think you should introduce a new Kconfig
> > option, you could keep the hacky U-Boot style and just add an
> > #if defined(CONFIG_MACH_SUN50I) || defined(CONFIG_MACH_SUN50I_H6)
> > to the two places instead.  
> 
> IIRC, the calibration is only needed for the eMMC though, so we'd need
> to check that against the MMC number too.

Is that so? I was looking at the Linux driver, and that one sets
can_calibrate for both the "normal" and eMMC A64 compatible strings.
Isn't the difference between the two the new timing mode, which the
eMMC doesn't have? This looks to be covered in U-Boot, though in a
similar hacky way.

Cheers,
Andre.