bootblock.c

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/* SPDX-License-Identifier: GPL-2.0-only */
 
#include <bootblock_common.h>
#include <soc/soc.h>
#include <soc/spi.h>
#include <soc/uart.h>
#include <soc/gpio.h>
#include <spi_flash.h>
#include <console/console.h>
#include <fmap.h>
#include "mainboard.h"
 
void bootblock_mainboard_early_init(void)
{
        /* Route UART0 to CON1 */
        gpio_output(ELGON_GPIO_UART_SEL, 0);
 
        /* Turn off error LED */
        gpio_output(ELGON_GPIO_ERROR_LED, 0);
 
        if (CONFIG(BOOTBLOCK_CONSOLE)) {
                if (!uart_is_enabled(CONFIG_UART_FOR_CONSOLE))
                        uart_setup(CONFIG_UART_FOR_CONSOLE, CONFIG_TTYS0_BAUD);
        }
}
 
static void configure_spi_flash(void)
{
        /* The maximum SPI frequency for error-free transmission is at 30 MHz */
        spi_init_custom(0, // bus
                        28000000, // speed Hz
                        0, // idle low disabled
                        0, // zero idle cycles between transfers
                        0, // MSB first
                        0, // Chip select 0
                        1); // assert is high
 
        /* Route SPI to SoC */
        gpio_output(ELGON_GPIO_SPI_MUX, 1);
}
 
/**
 * Handle flash write protection.
 * This code verifies the write-protection on each boot.
 * Enabling the write protection does only run on the first boot.
 * An error is fatal as it breaks the Chain Of Trust.
 */
static void protect_ro_rgn_spi_flash(void)
{
        const struct spi_flash *flash = boot_device_spi_flash();
        const char *fmapname = "WP_RO";
        struct region ro_rgn;
 
        if (fmap_locate_area(fmapname, &ro_rgn)) {
                printk(BIOS_ERR, "%s: No %s FMAP section.\n", __func__,
                        fmapname);
                die("Can't verify flash protections!");
        }
 
        u8 reg8 = 0;
        spi_flash_status(flash, &reg8);
 
        /* Check if SRP0 is set and RO region is protected */
        if (!(reg8 & 0x80) ||
            spi_flash_is_write_protected(flash, &ro_rgn) != 1) {
                printk(BIOS_WARNING, "%s: FMAP section %s is not write-protected\n",
                         __func__, fmapname);
 
                /*
                * Need to protect flash region :
                * WP_RO read only and use /WP pin
                * non-volatile programming
                */
                if (spi_flash_set_write_protected(flash, &ro_rgn,
                    SPI_WRITE_PROTECTION_PIN) != 0)
                        die("Failed to write-protect WP_RO region!");
        }
        printk(BIOS_INFO, "%s: FMAP section %s is write-protected\n",
               __func__, fmapname);
}
 
void bootblock_mainboard_init(void)
{
        configure_spi_flash();
        protect_ro_rgn_spi_flash();
}