[PATCH 2/2] mtd: nand: don't use read_buf for 8-bit ONFI transfers

[Ezequiel Garcia]

On Wed, Jan 29, 2014 at 02:18:29PM -0800, Brian Norris wrote:
> Use a repeated read_byte() instead of read_buf(), since for x16 buswidth
> devices, we need to avoid the upper I/O[16:9] bits. See the following
> commit for reference:
> 
> commit 05f7835975dad6b3b517f9e23415985e648fb875
> Author: Uwe Kleine-König <u.kleine-koenig at pengutronix.de>
> Date:   Thu Dec 5 22:22:04 2013 +0100
> 
>     mtd: nand: don't use {read,write}_buf for 8-bit transfers
> 
> Now, I think that all barriers to probing ONFI on x16 devices are
> removed, so remove the check from nand_flash_detect_onfi().
> 
> Tested on 8-bit ONFI NAND (Micron MT29F32G08CBADAWP).
> 
> Signed-off-by: Brian Norris <computersforpeace at gmail.com>

Tested-by: Ezequiel Garcia <ezequiel.garcia at free-electrons.com>

FWIW:

* 8-bit device, ONFI-probed
nand: device found, Manufacturer ID: 0x2c, Chip ID: 0xf1
nand: Micron MT29F1G08ABADAH4
nand: 128MiB, SLC, page size: 2048, OOB size: 64

* 16-bit device, ID-probed
nand: device found, Manufacturer ID: 0x2c, Chip ID: 0xcc
nand: Micron NAND 512MiB 3,3V 16-bit
nand: 512MiB, SLC, page size: 2048, OOB size: 64

* 16-bit (same) device, ONFI-probed
nand: device found, Manufacturer ID: 0x2c, Chip ID: 0xcc
nand: Micron MT29F4G16ABADAH4
nand: 512MiB, SLC, page size: 2048, OOB size: 64

-- 
Ezequiel García, Free Electrons
Embedded Linux, Kernel and Android Engineering
http://free-electrons.com