On Thu, Jun 29, 2017 at 10:29:08PM +0800, Jun Nie wrote:
> 2017-06-29 20:09 GMT+08:00 Leif Lindholm <leif.lindh...@linaro.org>:
> > On Thu, Jun 29, 2017 at 05:02:05PM +0800, Jun Nie wrote:
> >> The argument of CMD8 should be stuff bits according to standard
> >> JESD84-A44.
> >
> > OK, I realise that "stuff bits" is a term used by the spec, so that is
> > probably sufficient explanation even though the term was known to me.
> > And the MdeModulePkg driver seems to agree on the technical point.
> > My question is why zeroes is the correct "stuff bits" value?
>
> Yes, it is defined in page 2 in spec. I guess 0 is best filling value
> than other value when we do not need a real value.
> stuff bit: filling 0 bits to ensure fixed length frames for commands
> and responses.
Yeah, fair enough.
It literally is just "nothing".
Reviewed-by: Leif Lindholm <leif.lindh...@linaro.org>
Pushed as 0ad564ffe7.
(Oh, and "Add non-DDR timing mode support" which I had seen as a
companion patch to the ECSD alignment fix also pushed, as 44f4ff6257.)
/
Leif
> >> Contributed-under: TianoCore Contribution Agreement 1.0
> >> Signed-off-by: Jun Nie <jun....@linaro.org>
> >> ---
> >> EmbeddedPkg/Universal/MmcDxe/MmcIdentification.c | 2 +-
> >> 1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/EmbeddedPkg/Universal/MmcDxe/MmcIdentification.c
> >> b/EmbeddedPkg/Universal/MmcDxe/MmcIdentification.c
> >> index 4ce0ddd..c28207e 100644
> >> --- a/EmbeddedPkg/Universal/MmcDxe/MmcIdentification.c
> >> +++ b/EmbeddedPkg/Universal/MmcDxe/MmcIdentification.c
> >> @@ -210,7 +210,7 @@ EmmcIdentificationMode (
> >> }
> >>
> >> // Fetch ECSD
> >> - Status = Host->SendCommand (Host, MMC_CMD8, RCA);
> >> + Status = Host->SendCommand (Host, MMC_CMD8, 0);
> >> if (EFI_ERROR (Status)) {
> >> DEBUG ((EFI_D_ERROR, "EmmcIdentificationMode(): ECSD fetch error,
> >> Status=%r.\n", Status));
> >> }
> >> --
> >> 1.9.1
> >>
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