From: Tolunay Orkun <listmember@orkun.us>
To: u-boot@lists.denx.de
Subject: [U-Boot-Users] [PATCH] Fixed cfi flash read uchar bug.
Date: Mon, 29 Jan 2007 05:29:21 -0600 [thread overview]
Message-ID: <45BDDA91.3070303@orkun.us> (raw)
In-Reply-To: <46B96294322F7D458F9648B60E15112C082F7B@zch01exm26.fsl.freescale.net>
Zhang Wei-r63237 wrote:
>> Because the data we are interested in is only available in every
>> other byte?
>>
> Does it means if we need other byte data we can access them byte by byte? If we needn't we should not access them?
>
> Thanks!
> Zhang Wei
The current code works because most CPU Bus Interface Unit will execute
buswide cycles and discard the unused byte(s).
I understand that you would like to convert this code to use memcpy()
and pick various bytes from local ram instead of directly from flash.
Right? What exactly you are experiencing when you use current code.
Could you refresh my memory?
I do not like memcpy() as it is a black box. It could be implemented at
low level using string instructions, it could do various things for
different cpu architectures and various sizes so it could lead to very
hard to find issues.
My proposal for you to try: Do not depend on bus interface unit doing
buswide reads, explicitly read buswide chunks after doing the bus-wide
read into a temporary variable, pick the usable bytes from that
temporary variable. This should eliminate the bus interface unit
dependency of the CPU and possible board designer interfacing gimmicks.
Let us know how it goes (can you post your patch too so I can verify it).
Tolunay
next prev parent reply other threads:[~2007-01-29 11:29 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-12-22 7:27 [U-Boot-Users] [PATCH] Fixed cfi flash read uchar bug wei.zhang at freescale.com
2006-12-22 10:00 ` Wolfgang Denk
2006-12-22 11:02 ` Zhang Wei
2006-12-22 14:11 ` Wolfgang Denk
2006-12-22 16:34 ` [U-Boot-Users] 答复: " Zhang Wei-r63237
2006-12-22 17:17 ` Wolfgang Denk
2006-12-25 7:03 ` Zhang Wei
2006-12-25 23:24 ` Wolfgang Denk
2006-12-26 6:04 ` Zhang Wei
2007-01-04 2:07 ` Zhang Wei-r63237
2007-01-04 8:17 ` Wolfgang Denk
2007-01-04 8:36 ` Zhang Wei-r63237
2007-01-04 9:23 ` Wolfgang Denk
2007-01-04 11:19 ` Stefan Roese
2007-01-05 13:27 ` Stefan Roese
2007-01-07 10:12 ` Tolunay Orkun
2007-01-07 10:40 ` Wolfgang Denk
2007-01-13 7:11 ` Tolunay Orkun
2007-01-13 17:53 ` Håvard Skinnemoen
2007-01-16 6:52 ` Stefan Roese
2007-01-25 4:38 ` Zhang Wei-r63237
2007-01-25 16:10 ` Timur Tabi
2007-01-25 20:33 ` Wolfgang Denk
2007-01-26 2:13 ` Zhang Wei-r63237
2007-01-29 11:29 ` Tolunay Orkun [this message]
2007-01-30 3:36 ` Wang Haiying-r54964
2007-01-31 9:01 ` Tolunay Orkun
2007-01-31 19:25 ` Haiying Wang
2007-02-01 5:26 ` Tolunay Orkun
2007-02-01 22:06 ` Haiying Wang
2007-02-01 22:52 ` Chris Fester
2007-02-09 17:47 ` [U-Boot-Users] [PATCH0/2] Re-do the patch for adding DO_SYNC in flash_write_cmd Haiying Wang
2007-02-09 19:42 ` Wolfgang Denk
2007-02-09 19:48 ` Haiying Wang
2007-02-10 1:04 ` Wolfgang Denk
2007-02-10 7:23 ` Tolunay Orkun
2007-02-10 7:40 ` Stefan Roese
2007-02-10 7:57 ` Tolunay Orkun
2007-02-10 8:07 ` Stefan Roese
2007-02-10 21:55 ` Wolfgang Denk
2007-02-10 21:54 ` Wolfgang Denk
2007-02-11 2:34 ` Timur Tabi
2007-02-11 10:23 ` Wolfgang Denk
2007-02-09 19:59 ` Haavard Skinnemoen
2007-02-10 1:02 ` Wolfgang Denk
2007-02-09 17:47 ` [U-Boot-Users] [PATCH 1/2] Add DO_SYNC at the end of flash_write_cmd Haiying Wang
2007-02-09 19:45 ` Wolfgang Denk
2007-02-09 17:47 ` [U-Boot-Users] [PATCH 2/2] Define DO_SYNC in each CPU's header file Haiying Wang
2007-02-09 19:46 ` Wolfgang Denk
2007-02-10 7:17 ` Tolunay Orkun
2007-01-08 2:41 ` [U-Boot-Users] [PATCH] Fixed cfi flash read uchar bug Zhang Wei-r63237
2006-12-22 17:07 ` Chris Fester
2006-12-22 17:24 ` Wolfgang Denk
2006-12-22 17:42 ` Chris Fester
2006-12-22 21:33 ` Wolfgang Denk
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