[U-Boot] flash_real_protect() and CFI_CMDSET_AMD_STANDARD

[U-Boot] flash_real_protect() and CFI_CMDSET_AMD_STANDARD

[Timur Tabi]

I'm trying to add support for AMD manufacturer ID to flash_real_protect().
The code currently does this:

	case CFI_CMDSET_AMD_EXTENDED:
	case CFI_CMDSET_AMD_STANDARD:
		/* U-Boot only checks the first byte */
		if (info->manufacturer_id == (uchar)ATM_MANUFACT) {
			...
		}
		break;

Unfortunately, I don't really understand CFI programming that well, but from
my research, it appears to me that AMD chips that implement the AMD standard
command set will work with this code:

	case CFI_CMDSET_INTEL_PROG_REGIONS:
	case CFI_CMDSET_INTEL_STANDARD:
	case CFI_CMDSET_INTEL_EXTENDED:
		flash_write_cmd (info, sector, 0,
				 FLASH_CMD_CLEAR_STATUS);
		flash_write_cmd (info, sector, 0, FLASH_CMD_PROTECT);
		if (prot)
			flash_write_cmd (info, sector, 0,
				FLASH_CMD_PROTECT_SET);
		else
			flash_write_cmd (info, sector, 0,
				FLASH_CMD_PROTECT_CLEAR);
		break;

So I don't understand the need for Rafael Campos' patch:

http://lists.denx.de/pipermail/u-boot/2008-July/037419.html

It looks as if Rafael removed support for hardware flash protection from all
AMD standard/extended flash chips that are not made by Atmel.

-- 
Timur Tabi
Linux kernel developer at Freescale

[U-Boot] flash_real_protect() and CFI_CMDSET_AMD_STANDARD

[Stefan Roese]

Hi Timur,

On Friday 14 May 2010 21:17:44 Timur Tabi wrote:
> I'm trying to add support for AMD manufacturer ID to flash_real_protect().
> The code currently does this:
> 
> 	case CFI_CMDSET_AMD_EXTENDED:
> 	case CFI_CMDSET_AMD_STANDARD:
> 		/* U-Boot only checks the first byte */
> 		if (info->manufacturer_id == (uchar)ATM_MANUFACT) {
> 			...
> 		}
> 		break;
> 
> Unfortunately, I don't really understand CFI programming that well, but
> from my research, it appears to me that AMD chips that implement the AMD
> standard command set will work with this code:
> 
> 	case CFI_CMDSET_INTEL_PROG_REGIONS:
> 	case CFI_CMDSET_INTEL_STANDARD:
> 	case CFI_CMDSET_INTEL_EXTENDED:
> 		flash_write_cmd (info, sector, 0,
> 				 FLASH_CMD_CLEAR_STATUS);
> 		flash_write_cmd (info, sector, 0, FLASH_CMD_PROTECT);
> 		if (prot)
> 			flash_write_cmd (info, sector, 0,
> 				FLASH_CMD_PROTECT_SET);
> 		else
> 			flash_write_cmd (info, sector, 0,
> 				FLASH_CMD_PROTECT_CLEAR);
> 		break;

Yes, you might be correct here. I have to admit that I never used 
CONFIG_SYS_FLASH_PROTECTION on AMD/Spansion type FLASH chips though.
 
> So I don't understand the need for Rafael Campos' patch:
> 
> http://lists.denx.de/pipermail/u-boot/2008-July/037419.html
> 
> It looks as if Rafael removed support for hardware flash protection from
> all AMD standard/extended flash chips that are not made by Atmel.

Yes, it definitely looks that way. I have missed this. Thanks for looking into 
this. It would be great if you could send a patch fixing this.

Thanks.

Cheers,
Stefan

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