[U-Boot] [PATCH 00/18] Support for eMMC partitioning and related fixes

[Diego Santa Cruz]

Hi,

> -----Original Message-----
> From: Joakim Tjernlund [mailto:joakim.tjernlund at transmode.se]
> Sent: Friday, November 28, 2014 11:05 AM
> To: Diego Santa Cruz
> Cc: panto at antoniou-consulting.com; u-boot at lists.denx.de
> Subject: Re: [U-Boot] [PATCH 00/18] Support for eMMC partitioning and related
> fixes
> >
> > I have the need to hardware partition eMMC devices from U-Boot along
> > with setting enhanced and reliable write attributes.
> >
> > This series of patches adds this support to U-Boot via a new mmc
> > API, a few new members of struct mmc and a new mmc sub-command. It
> > also features several fixes to the eMMC hardware partition support. I
> > have tested this with Micron eMMC 4.41 parts and it is working as
> > expected.
> 
> This is really great, thanks.

Good to know it may be useful to other people.

> 
> I do wonder(I am fairly new to eMMC) about 512B emulation.
> In mmc utils there is a:
> mmc disable 512B emulation <device>
>         Set the eMMC data sector size to 4KB by disabling emulation on
> <device>.
> 
> I am hoping 4K size will increase performance and reliability?
> Could you add this feature too to your patch set?
>

I think this was introduced in eMMC 4.51. I do not have any 4.51 devices at hand to test with but I am not sure there would be any performance benefit to issue reads and writes in the 4KB large sector size. All eMMC devices I've seen write in chunks much larger than 4 KB internally anyhow (the ones I'm using now have a superpage size of 32 KB). Writes should be aligned to the superpage size to get good performance.

Best,

Diego

-- 
Diego Santa Cruz, PhD
Technology Architect
spinetix.com