cbfs_spi.c

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/* SPDX-License-Identifier: GPL-2.0-only */
 
/*
 * This file provides a common CBFS wrapper for SPI storage. SPI driver
 * context is expanded with the buffer descriptor used to store data read from
 * SPI.
 */
 
#include <boot_device.h>
#include <cbfs.h>
#include <console/console.h>
#include <spi_flash.h>
#include <symbols.h>
#include <stdint.h>
#include <timer.h>
 
static struct spi_flash spi_flash_info;
static bool spi_flash_init_done;
 
/*
 * SPI speed logging for big transfers available with BIOS_DEBUG. The format is:
 *
 * read SPI 0x62854 0x7db7: 10416 us, 3089 KB/s, 24.712 Mbps
 *
 * The important number is the last one. It should roughly match your SPI
 * clock. If it doesn't, your driver might need a little tuning.
 */
static ssize_t spi_readat(const struct region_device *rd, void *b,
                                size_t offset, size_t size)
{
        struct stopwatch sw;
        bool show = size >= 4 * KiB && console_log_level(BIOS_DEBUG);
 
        if (show)
                stopwatch_init(&sw);
        if (spi_flash_read(&spi_flash_info, offset, size, b))
                return -1;
        if (show) {
                long usecs;
 
                usecs = stopwatch_duration_usecs(&sw);
                u64 speed;      /* KiB/s */
                int bps;        /* Bits per second */
 
                speed = size * (u64)1000 / usecs;
                bps = speed * 8;
 
                printk(BIOS_DEBUG, "read SPI %#zx %#zx: %ld us, %lld KB/s, %d.%03d Mbps\n",
                       offset, size, usecs, speed, bps / 1000, bps % 1000);
        }
        return size;
}
 
static ssize_t spi_writeat(const struct region_device *rd, const void *b,
                                size_t offset, size_t size)
{
        if (spi_flash_write(&spi_flash_info, offset, size, b))
                return -1;
        return size;
}
 
static ssize_t spi_eraseat(const struct region_device *rd,
                                size_t offset, size_t size)
{
        if (spi_flash_erase(&spi_flash_info, offset, size))
                return -1;
        return size;
}
 
/* Provide all operations on the same device. */
static const struct region_device_ops spi_ops = {
        .mmap = mmap_helper_rdev_mmap,
        .munmap = mmap_helper_rdev_munmap,
        .readat = spi_readat,
        .writeat = spi_writeat,
        .eraseat = spi_eraseat,
};
 
static struct mmap_helper_region_device mdev =
        MMAP_HELPER_DEV_INIT(&spi_ops, 0, CONFIG_ROM_SIZE, &cbfs_cache);
 
void boot_device_init(void)
{
        int bus = CONFIG_BOOT_DEVICE_SPI_FLASH_BUS;
        int cs = 0;
 
        if (spi_flash_init_done == true)
                return;
 
        if (spi_flash_probe(bus, cs, &spi_flash_info))
                return;
 
        spi_flash_init_done = true;
}
 
/* Return the CBFS boot device. */
const struct region_device *boot_device_ro(void)
{
        if (spi_flash_init_done != true)
                return NULL;
 
        return &mdev.rdev;
}
 
/* The read-only and read-write implementations are symmetric. */
const struct region_device *boot_device_rw(void)
{
        return boot_device_ro();
}
 
const struct spi_flash *boot_device_spi_flash(void)
{
        boot_device_init();
 
        if (spi_flash_init_done != true)
                return NULL;
 
        return &spi_flash_info;
}