src/mainboard/emulation/qemu-q35/bootblock.c

#include <arch/io.h>

/* Just define these here, there is no gm35.h file to include. */
#define D0F0_PCIEXBAR_LO 0x60
#define D0F0_PCIEXBAR_HI 0x64

static void bootblock_northbridge_init(void)
{
	uint32_t reg;

	/*
	 * The "io" variant of the config access is explicitly used to
	 * setup the PCIEXBAR because CONFIG_MMCONF_SUPPORT_DEFAULT is set to
	 * to true. That way all subsequent non-explicit config accesses use
	 * MCFG. This code also assumes that bootblock_northbridge_init() is
	 * the first thing called in the non-asm boot block code. The final
	 * assumption is that no assembly code is using the
	 * CONFIG_MMCONF_SUPPORT_DEFAULT option to do PCI config acceses.
	 *
	 * The PCIEXBAR is assumed to live in the memory mapped IO space under
	 * 4GiB.
	 */
	reg = 0;
	pci_io_write_config32(PCI_DEV(0,0,0), D0F0_PCIEXBAR_HI, reg);
	reg = CONFIG_MMCONF_BASE_ADDRESS | 1; /* 256MiB - 0-255 buses. */
	pci_io_write_config32(PCI_DEV(0,0,0), D0F0_PCIEXBAR_LO, reg);
}

static void bootblock_mainboard_init(void)
{
	bootblock_northbridge_init();
	bootblock_southbridge_init();
}