From: Reinhard Meyer <u-boot@emk-elektronik.de>
To: u-boot@lists.denx.de
Subject: [U-Boot] Non standard CFI detection tweaks
Date: Thu, 12 Aug 2010 15:14:20 +0200 [thread overview]
Message-ID: <4C63F3AC.4070201@emk-elektronik.de> (raw)
In-Reply-To: <201008121440.01113.sr@denx.de>
Stefan Roese wrote:
> Hi Rogan,
>
> On Thursday 12 August 2010 14:07:03 Rogan Dawes wrote:
>> I found the following configuration snippet for OpenOCD for the DNS323
>> at http://wiki.dns323.info/hardware:jtag:
>>
>> # driver addr size chip_width bus_width options
>> flash bank cfi 0xff800000 0x800000 1 2 0
>>
>> It seems that the key here is that the bus_width is set to 2, even
>> though the chip_width is only 1.
>
> Seems not to be so uncommon: 8bit device on a 16bit external bus.
It is mostly likely a 8/16 bit wide device in 8 bit mode on an 8 bit
external bus. Then all CFI data appears twice.
Reason: the chip presents CFI data correctly (from the flash point of view)
in 16 bit mode (flash A0 connected to CPU A1). If connected in 8 bit mode
(flash A0 connected to CPU A1, flash A-1 connected to CPU A0) it still
presents the data at the same adresses but the CFI driver gets misled
because its told to try for 8 bit wide flash.
Since that was an issue long ago, I made the board/emk/common/flash.c
(CFI) driver. Anyone is welcome to add that special handling for 16 bit
flash connected in 8 bit mode to the general CFI driver :)
Best Regards,
Reinhard
next prev parent reply other threads:[~2010-08-12 13:14 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-13 20:00 [U-Boot] Non standard CFI detection tweaks Rogan Dawes
2010-07-19 9:34 ` Stefan Roese
2010-07-19 10:18 ` Rogan Dawes
2010-07-19 10:49 ` Stefan Roese
2010-07-19 11:05 ` Rogan Dawes
2010-07-19 11:50 ` Stefan Roese
2010-07-19 12:18 ` Rogan Dawes
2010-07-19 13:33 ` Stefan Roese
2010-07-19 14:37 ` Rogan Dawes
2010-07-20 7:58 ` Stefan Roese
2010-07-20 8:38 ` Rogan Dawes
2010-07-20 10:00 ` Rogan Dawes
2010-07-20 10:06 ` Reinhard Meyer
2010-07-20 10:22 ` Reinhard Meyer
2010-07-20 10:29 ` Rogan Dawes
2010-07-20 10:53 ` Reinhard Meyer
2010-07-20 11:01 ` Rogan Dawes
2010-07-23 10:17 ` Albert ARIBAUD
2010-08-12 12:07 ` Rogan Dawes
2010-08-12 12:40 ` Stefan Roese
2010-08-12 13:14 ` Reinhard Meyer [this message]
2010-08-12 13:26 ` Rogan Dawes
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