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/* SPDX-License-Identifier: GPL-2.0-only */
#include <arch/bootblock.h>
#include <assert.h>
#include <device/pci_ops.h>
#include <types.h>
#include "i945.h"
static uint32_t encode_pciexbar_length(void)
{
switch (CONFIG_MMCONF_BUS_NUMBER) {
case 256: return 0 << 1;
case 128: return 1 << 1;
case 64: return 2 << 1;
default: return dead_code_t(uint32_t);
}
}
void bootblock_early_northbridge_init(void)
{
/*
* The "io" variant of the config access is explicitly used to setup the PCIEXBAR
* because CONFIG(MMCONF_SUPPORT) is set 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) option to do PCI config accesses.
*
* The PCIEXBAR is assumed to live in the memory mapped IO space under 4GiB.
*/
const uint32_t reg32 = CONFIG_MMCONF_BASE_ADDRESS | encode_pciexbar_length() | 1;
pci_io_write_config32(HOST_BRIDGE, PCIEXBAR, reg32);
}
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