[U-Boot] [U-Boot,PATCHv4] Optimized nand_read_buf for kirkwood

[Scott Wood]

On Mon, Aug 26, 2013 at 02:10:56PM +0200, Phil Sutter wrote:
> From: Nico Erfurth <ne at erfurth.eu>
> 
> The basic idea is taken from the linux-kernel, but further optimized.
> 
> First align the buffer to 8 bytes, then use ldrd/strd to read and store
> in 8 byte quantities, then do the final bytes.
> 
> Tested using: 'date ; nand read.raw 0xE00000 0x0 0x10000 ; date'.
> Without this patch, NAND read of 132MB took 49s (~2.69MB/s). With this
> patch in place, reading the same amount of data was done in 27s
> (~4.89MB/s). So read performance is increased by ~80%!
> 
> Signed-off-by: Nico Erfurth <ne at erfurth.eu>
> Tested-by: Phil Sutter <phil.sutter at viprinet.com>
> Cc: Prafulla Wadaskar <prafulla at marvell.com>
> 
> ---
> Changed since V3:
> - fixed author
> ---
>  drivers/mtd/nand/kirkwood_nand.c | 32 ++++++++++++++++++++++++++++++++
>  1 file changed, 32 insertions(+)

I tried to build-test this, and I couldn't find any board that defines
CONFIG_NAND_KIRKWOOD.

The patch that removed it was commit
b5befd8211b54ae2d2fca3fbed061c879951ceaa ("arm/km: fix u-boot.kwb build
breakage"), over two years ago.  It's not clear whether the removal was
intentional.

What target did you use to test this?

-Scott