[PATCH] arm: mmci: Add ARM variant with extended FIFO

[Russell King - ARM Linux]

On Wed, Mar 16, 2011 at 10:25:16AM -0600, Matt Waddel wrote:
> On 03/11/2011 10:18 AM, Pawel Moll wrote:
> > New IO FPGA implementation for Versatile Express boards contain
> > MMCI (PL180) cell with FIFO extended to 128 words (512 bytes).
> > 
> > Signed-off-by: Pawel Moll <pawel.moll at arm.com>
> 
> Tested-by: Matt Waddel <matt.waddel at linaro.org>
> 
> This patch improves MMC performance on my vexpress system. Also
> fixes "mmcblk0: error -5 transferring data" errors.

You should use the patch I sent to do dynamic clocking if you're
concerned about performance.  That patch improves performance by
a factor of 8 compared to anything possible by increasing the FIFO
depth.

I am very much of the opinion that deepening the FIFOs is just a
sticky plaster over the problem - and I said as much when it was
first proposed, pointing out that there's other better solutions.