Re: [U-Boot] [PATCH] cfi_flash: Micron Nor flash don't support read operation after send write command

12 Mar 2014

Hi Stefan,
ok, got it.
Because I saw the patch format is malformed in the website http://patchwork.ozlabs.org/project/uboot/list/, so I send this patch three times. You can reference the last patch I submit. It's my first time to submit Patch to Uboot community. Sorry for bring inconvenient for you. 
Sorry for that. 
Anyway, can you help check if the patch I submit make sense?
Thanks a lot
-----Original Message-----
From: Stefan Roese [mailto:sr@denx.de] 
Sent: Wednesday, March 12, 2014 1:14 PM
To: Qi Wang 王起 (qiwang); u-boot@lists.denx.de
Subject: Re: [U-Boot] [PATCH] cfi_flash: Micron Nor flash don't support read operation after send write command
Hi Qi Wang,
please don't send this patch so often.
On 11.03.2014 09:46, Qi Wang 王起 (qiwang) wrote:
...
Micron Nor flash don't support read operation after send write command.
Are all Micon NOR flash chips affected by this? Or only some chips? 
Please list the chips/families and best add a link to the description of 
this unsupported operation mode (chapter in data-sheet or errata).
Find a few more comments below.
...
As below,
flash_write_cmd(info, sector, offset, AMD_CMD_WRITE_TO_BUFFER);
   cnt = len >> shift;
   flash_write_cmd(info, sector, offset, cnt - 1);
switch (info->portwidth) {
   case FLASH_CFI_8BIT:
   	while (cnt-- > 0) {
   		flash_write8(flash_read8(src), dst);
   		src += 1, dst += 1;
   	}
   break;
If the src address locate in NOR flash, flash_read operation will be failed.
So, read out the data to DRAM before send write command operation.
Signed-off-by: Qi Wangqiwang@micron.com
drivers/mtd/cfi_flash.c |   70 +++++++++++++++++++++++++++++++----------------
  1 file changed, 46 insertions(+), 24 deletions(-)

diff --git a/drivers/mtd/cfi_flash.c b/drivers/mtd/cfi_flash.c index a389cd1..0f532c0 100644
--- a/drivers/mtd/cfi_flash.c
+++ b/drivers/mtd/cfi_flash.c
@@ -25,6 +25,8 @@
  #include <environment.h>
  #include <mtd/cfi_flash.h>
  #include <watchdog.h>
+#include <malloc.h>
+#include <asm-generic/errno.h>
/*

This file implements a Common Flash Interface (CFI) driver for @@ -855,6 +857,8 @@ static int flash_write_cfibuffer (flash_info_t * info, ulong dest, uchar * cp,

int cnt;
   int retcode;
   void *src = cp;

void *src2;
void *src2_bak;
void *dst = (void *)dest;
void *dst2 = dst;
int flag = 1;

@@ -880,29 +884,45 @@ static int flash_write_cfibuffer (flash_info_t * info, ulong dest, uchar * cp,
   	goto out_unmap;
   }

src2 = malloc(len);

Naming is not optimal, at least for my taste. My not use "src_buf"?
...

if(!src2)
{
free(src2);


return -ENOMEM;


}

Incorrect coding style. Please use something like this instead:
if (!src2) {
    	free(src2);
    	return -ENOMEM;
    }
Thanks,
Stefan

    