[U-Boot] [PATCH 1/3] mmc: limit block count for multi-block write commands

[Lei Wen]

Hi Reinhard,


> Besides that my remarks to yesterdays patch of yours are still valid:
> Those "magic numbers" are due to a specific hardware controller/limitation
> and not any SD/MMC card limitation.
>
> And which hardware driver are you using this with?
> Maybe some context would help.
> Maybe the splitting could be done in the hardware driver and not in this
> generic part?
>
Certainly those limitation could not be put at the generic part. But
for the common limitation from the spec,
I believe put there is a better choice. I mention for the sd host
controller standard spec has such limitation for a maximum blocks at
one go.
You could refer to the pdf doc at:
http://www.sdcard.org/developers/tech/host_controller/simple_spec/Simplified_SD_Host_Controller_Spec.pdf
The register table at page 20 shows the block count register is only
16 bit width.

For the 524288 magic number, 512k, I just follow the Linux way, that
is don't let the driver to bother to handle the dma boundary if it use
sdma instead PIO.

So it is not which hardware's question.

Best regards,
Lei