在 2016/6/22 20:37, Ulf Hansson 写道:
On 8 June 2016 at 10:19, Shawn Lin <shawn.lin@xxxxxxxxxxxxxx> wrote:
Hi all,
This patchset is gonna improve the card's init sequence
by exposing some caps to DT.
The basic idea is to skip sending specific init cmd inspired
by Carlo Caione's commit[0].
To make it possible, I firstly expose Carlo's MMC_CAP2_NO_SDIO
to DT and extend two new caps for similar usage of sd and mmc.
We probably need it because for most of the boards, each of the
slots should have a specific function when designed. It's impossible
for one slot which can either to be used as eMMC or a SD card for a
given board. The same for SDIO case.
We could have two ways to improve it
A) Skip sending specific commands if knowing we don't support
the specific card type.
B) Allow sending specific commands if knowing we do support
the specific card type.
A) and B) shouldn't have difference, but I take A) as the final
one as it looks more consistent with Carlo's way, which does not
seem to break anything as possible.
The only roadblock for this patchset to be landed should be the
improvement we gain from it. Theoretically sdio-card doesn't get
improvment as it's already in the first place to be attached.
But considering the sd and (e)MMC case, we should gain more benifit
from it.
From the test, we can save nearly 2ms for attaching emmc against the
original 8ms. And we gain more than 30us improvement for sd card for
each insert.
[0]: http://permalink.gmane.org/gmane.linux.kernel.mmc/34774
Shawn Lin (4):
Documentation: mmc: add description for new caps
mmc: core: expose MMC_CAP2_NO_SDIO to dt-binding
mmc: core: add cap-no-sd and cap-no-mmc properties
mmc: core: improve initialization flow
I would prefer that you restructure this series a bit.
I will do it and I think Doug was asking we to drop the "cap-"
prefix which I think need to be clarified before sending
non-RFC one. :)
Start by adding each new MMC_CAP2* separately and without involving
the DT parsing.
Make the DT documentation patch come after the above, and add a new
separate patch which exposes the caps to device tree.
In that way, I can pick up the non DT parts and wait for Rob's
ack/nack of the DT bindings.
Kind regards
Uffe
Documentation/devicetree/bindings/mmc/mmc.txt | 3 +++
drivers/mmc/core/core.c | 10 +++++-----
drivers/mmc/core/host.c | 6 ++++++
include/linux/mmc/host.h | 2 ++
4 files changed, 16 insertions(+), 5 deletions(-)
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2.3.7
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Best Regards
Shawn Lin
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