bootblock.c

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/* SPDX-License-Identifier: GPL-2.0-or-later */
 
#include <stdint.h>
#include <arch/bootblock.h>
#include <device/pci_ops.h>
#include <device/pci_ids.h>
#include <device/pci_type.h>
#include "i82371eb.h"
 
#define PCI_ID(VENDOR_ID, DEVICE_ID) \
        ((((DEVICE_ID) & 0xFFFF) << 16) | ((VENDOR_ID) & 0xFFFF))
 
static pci_devfn_t pci_locate_device(unsigned int pci_id, pci_devfn_t dev)
{
        for (; dev <= PCI_DEV(255, 31, 7); dev += PCI_DEV(0, 0, 1)) {
                unsigned int id;
                id = pci_read_config32(dev, 0);
                if (id == pci_id)
                        return dev;
        }
        return PCI_DEV_INVALID;
}
 
/* TODO: Does not need to happen before console init. */
/* The whole rom is not accessible before this so limit
   the bootblock size. */
#if CONFIG_C_ENV_BOOTBLOCK_SIZE > 0x10000
#error "CONFIG_C_ENV_BOOTBLOCK_SIZE needs to be below 64KiB"
#endif
void bootblock_early_southbridge_init(void)
{
        u16 reg16;
 
        /*
         * Note: The Intel 82371AB/EB/MB ISA device can be on different
         * PCI bus:device.function locations on different boards.
         * Examples we encountered: 00:07.0, 00:04.0, or 00:14.0.
         * But scanning for the PCI IDs (instead of hardcoding
         * bus/device/function numbers) works on all boards.
         */
        const pci_devfn_t dev = pci_locate_device(PCI_ID(PCI_VID_INTEL,
                                       PCI_DID_INTEL_82371AB_ISA), 0);
 
        /* Enable access to the whole ROM, disable ROM write access. */
        reg16 = pci_read_config16(dev, XBCS);
        reg16 |= LOWER_BIOS_ENABLE | EXT_BIOS_ENABLE | EXT_BIOS_ENABLE_1MB;
        reg16 &= ~(WRITE_PROTECT_ENABLE);       /* Disable ROM write access. */
        pci_write_config16(dev, XBCS, reg16);
 
        /* Enable (RTC and) upper NVRAM bank. */
        pci_write_config8(dev, RTCCFG, RTC_POS_DECODE | UPPER_RAM_EN | RTC_ENABLE);
}