[flashrom] [PATCH] Refactor MCP SPI detection

Michael Karcher flashrom at mkarcher.dialup.fu-berlin.de
Wed Feb 17 15:50:37 CET 2010


Am Mittwoch, den 17.02.2010, 15:19 +0100 schrieb Carl-Daniel Hailfinger:
> Refactor MCP SPI detection:
> - Set supported buses based on ISA bridge reg 0x8a
> - Use MCP55 chipset enable only if LPC is detected
> - Allow LPC on MCP61
> - Eliminate duplicated code where possible
Sounds great.

>  	/* dev is the ISA bridge. No idea what the stuff below does. */
>  	byte = pci_read_byte(dev, 0x8a);
> -	msg_pdbg("ISA bridge reg 0x8a contents: 0x%02x, bit 6 is %i, bit 5 is "
> -		 "%i\n", byte, (byte >> 6) & 0x1, (byte >> 5) & 0x1);
> -	msg_pdbg("Guessed flash bus type is %s\n", ((byte >> 5) & 0x3) == 0x2 ?
> -		 "SPI" : "unknown, probably LPC");
> +	msg_pdbg("ISA/LPC bridge reg 0x8a contents: 0x%02x, bit 6 is %i, bit 5 "
> +		 "is %i\n", byte, (byte >> 6) & 0x1, (byte >> 5) & 0x1);
> +	switch ((byte >> 5) & 0x3) {
> +	case 0x0:
> +		buses_supported = CHIP_BUSTYPE_LPC;
> +		break;
> +	case 0x2:
> +		buses_supported = CHIP_BUSTYPE_SPI;
> +		break;
> +	default:
> +		buses_supported = CHIP_BUSTYPE_UNKNOWN;
> +		break;
> +	}
> +	busname = flashbuses_to_text(buses_supported);
> +	msg_pdbg("Guessed flash bus type is %s\n", busname);
> +	free(busname);
Hmm. I think there was a report with 0x1 for LPC, but I have to recheck
that.

> @@ -1088,8 +1097,9 @@
>  	/* Look for the SMBus device (SMBus PCI class) */
>  	smbusdev = pci_dev_find_vendorclass(0x10de, 0x0c05);
>  	if (!smbusdev) {
> -		msg_perr("ERROR: SMBus device not found. Aborting.\n");
> -		exit(1);
> +		msg_perr("ERROR: SMBus device not found.\n");
> +		buses_supported = CHIP_BUSTYPE_NONE;
> +		return 1;
We don't need the SMBus device for LPC flashing, unless GPIOs are to be
toggled.

> +	} else if (mcp_spibaraddr && !(buses_supported & CHIP_BUSTYPE_SPI)) {
> +		msg_pdbg("Strange. MCP SPI BAR is valid, but chipset apparently"
> +			 " doesn't support SPI.\n");
The chipset might support SPI, it's just not enabled. Maybe more like
"flash chip apperently is not SPI".

> +/**
> + * The MCP67 code is guesswork based on cleanroom reverse engineering.
> + * Due to that, it only reads info and doesn't change any settings.
> + * It is assumed that LPC chips need the MCP55 code and SPI chips need the
For the MCP61, I have seen the MCP55 code in an board enable.

Regards,
  Michael Karcher





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