Re: [PATCH] mtd: spi-nor: read 6 bytes for the ID

Huang Shijie
2014-05-30T02:11:46Z

On Thu, May 29, 2014 at 10:58:52PM +0200, Marek Vasut wrote:
> On Wednesday, May 28, 2014 at 07:22:40 AM, Huang Shijie wrote:
> [...]
> > From 7b920141899e4e7249bd23792dc8d5f1558cb7ca Mon Sep 17 00:00:00 2001
> > From: Huang Shijie <b32955@freescale.com>
> > Date: Mon, 14 Apr 2014 18:09:34 +0800
> > Subject: [PATCH v2] mtd: spi-nor: read 6 bytes for the ID
> >
> > Currently, we read 5 bytes for ID, but s25fl128s has the same
> > ext_id(0x4d01) with s25fl129p1. The s25fl128s can support the DDR Quad
> > read, while s25fl129p1 does not. So we have to distinguish the two NOR
> > flashs.
> >
> > This patch reads out 6 bytes for the ID, and use the 6 bytes ID to search
> > the right flash_info.
> >
> > The detail of the patch is:
> > [1] change the "ext_id" from u16 to u32.
> > We can store two bytes or three bytes with the @ext_id now.
> >
> > [2] search the right flash_info with the 6byte ID and the new @ext_id.
> > We use "matched" variable to track the legacy two bytes @ext_id.
> > If the flash_info's @ext_id is three bytes, we will use the
> > sixth byte of the ID to check it.
> >
> > [3] add the new item to spi_nor_ids for s25fl128s.
> >
> > Signed-off-by: Huang Shijie <b32955@freescale.com>
> > ---
> > drivers/mtd/spi-nor/spi-nor.c | 30 +++++++++++++++++++++++++-----
> > 1 files changed, 25 insertions(+), 5 deletions(-)
>
> What exactly changed here please ?

This patch will reset the ext_jedec to the old value if the sixth-byte-match fails.

------------------------------------------------------------
+ /* reset back the ext_jedec */
+ ext_jedec >>= 8;
------------------------------------------------------------

thanks
Huang Shijie