On Thu, 2015-09-24 at 13:59 +0200, Hans de Goede wrote:
Hi,
On 24-09-15 12:29, Ian Campbell wrote:
On Thu, 2015-09-24 at 12:01 +0200, Hans de Goede wrote:
Hi,
On 24-09-15 11:40, Ian Campbell wrote:
On Wed, 2015-09-23 at 21:59 +0200, Hans de Goede wrote:
In recent allwinner kernel sources the mmc clk-delay settings have been slightly tweaked, and for sun9i they are completely different then what we are using.
This commit brings us in sync with what allwinner does, fixing problems accessing sdcards on some A33 devices (and likely others).
For pre sun9i hardware this makes the following changes: -At 400Khz change the sample delay from 7 to 0 (first introduced in A31 sdk)
This one applied to sun9i as well as pre I think?
-At 50 Mhz change the sample delay from 5 to 4 (first introduced in A23 sdk)
By my reading it also changes oclk from 2 to 1 on <sun9i @ >50MHz.
Right, I did not list that as we never do > 50MHz,
But the being changed here does handle that (the else hz > 50000000 case) and that is changing even if we somehow coincidentally arrange that this code is never used today I think it is worth mentioning so that if it does become used we have the history of when/why it was changed.
Ok, I'll amend the commit message.
Thanks.
later on in the code we've:
cfg->f_max = 52000000;
And that 52 is somewhat symbolically there, it is meant for 52MHz sdio where as mmc / sdcards run at 50MHz max.
Are these timings used for sdio as well then? That seems worth noting.
Yes, but we never use sdio in u-boot, more in general mmc/sdio is usually used referred to as just mmc (see e.g. the subsystem name, etc.).
Right, which makes it all the more likely that one day this code might be used for sdio too I think.
Ian.