[coreboot] [PATCH] Add option 'compress ramstage'

[Stefan Reinauer]

* Sven Schnelle <svens at stackframe.org> [110502 16:13]:
> Add an option to make compression of ramstage configurable. Right now
> it is always compressed. On my Thinkpad, the complete boot to grub takes
> 4s, with around 1s required for decompressing ramstage. This is probably
> caused by the fact the decompression does a lot of single byte/word/qword
> accesses, which are really slow on SPI buses. So give the user the option
> to store ramstage uncompressed, if he has enough memory.

Hi Sven,

can you try whether your thinkpad can boot faster if you enable spi
prefetching in src/southbridge/intel/i82801gx/bootblock.c

i.e.

static void enable_spi_prefetch(void)
{
        u8 reg8;
        device_t dev;

        dev = PCI_DEV(0, 0x1f, 0);

        reg8 = pci_read_config8(dev, 0xdc);
        reg8 &= ~(3 << 2);
        reg8 |= (2 << 2); /* Prefetching and Caching Enabled */
        pci_write_config8(dev, 0xdc, reg8);
}

static void bootblock_southbridge_init(void)
{
        ...
        enable_spi_prefetch();
        ...
}

Stefan