// SPDX-License-Identifier: GPL-2.0+
/*
 * Simulate an I2C eeprom
 *
 * Copyright (c) 2014 Google, Inc
 */

#include <common.h>
#include <dm.h>
#include <errno.h>
#include <i2c.h>
#include <log.h>
#include <malloc.h>
#include <asm/test.h>

#ifdef DEBUG
#define debug_buffer print_buffer
#else
#define debug_buffer(x, ...)
#endif

struct sandbox_i2c_flash_plat_data {
        enum sandbox_i2c_eeprom_test_mode test_mode;
        const char *filename;
        int offset_len;         /* Length of an offset in bytes */
        int size;               /* Size of data buffer */
        uint chip_addr_offset_mask; /* mask of addr bits used for offset */
};

struct sandbox_i2c_flash {
        uint8_t *data;
        uint prev_addr;         /* slave address of previous access */
        uint prev_offset;       /* offset of previous access */
};

void sandbox_i2c_eeprom_set_test_mode(struct udevice *dev,
                                      enum sandbox_i2c_eeprom_test_mode mode)
{
        struct sandbox_i2c_flash_plat_data *plat = dev_get_platdata(dev);

        plat->test_mode = mode;
}

void sandbox_i2c_eeprom_set_offset_len(struct udevice *dev, int offset_len)
{
        struct sandbox_i2c_flash_plat_data *plat = dev_get_platdata(dev);

        plat->offset_len = offset_len;
}

void sandbox_i2c_eeprom_set_chip_addr_offset_mask(struct udevice *dev,
                                                  uint mask)
{
        struct sandbox_i2c_flash_plat_data *plat = dev_get_platdata(dev);

        plat->chip_addr_offset_mask = mask;
}

uint sanbox_i2c_eeprom_get_prev_addr(struct udevice *dev)
{
        struct sandbox_i2c_flash *priv = dev_get_priv(dev);

        return priv->prev_addr;
}

uint sanbox_i2c_eeprom_get_prev_offset(struct udevice *dev)
{
        struct sandbox_i2c_flash *priv = dev_get_priv(dev);

        return priv->prev_offset;
}

static int sandbox_i2c_eeprom_xfer(struct udevice *emul, struct i2c_msg *msg,
                                  int nmsgs)
{
        struct sandbox_i2c_flash *priv = dev_get_priv(emul);
        struct sandbox_i2c_flash_plat_data *plat = dev_get_platdata(emul);
        uint offset = msg->addr & plat->chip_addr_offset_mask;

        debug("\n%s\n", __func__);
        debug_buffer(0, priv->data, 1, 16, 0);

        /* store addr for testing visibity */
        priv->prev_addr = msg->addr;

        for (; nmsgs > 0; nmsgs--, msg++) {
                int len;
                u8 *ptr;

                if (!plat->size)
                        return -ENODEV;
                len = msg->len;
                debug("   %s: msg->addr=%x msg->len=%d",
                      msg->flags & I2C_M_RD ? "read" : "write",
                      msg->addr, msg->len);
                if (msg->flags & I2C_M_RD) {
                        if (plat->test_mode == SIE_TEST_MODE_SINGLE_BYTE)
                                len = 1;
                        debug(", offset %x, len %x: ", offset, len);
                        if (offset + len > plat->size) {
                                int overflow = offset + len - plat->size;
                                int initial = len - overflow;

                                memcpy(msg->buf, priv->data + offset, initial);
                                memcpy(msg->buf + initial, priv->data,
                                       overflow);
                        } else {
                                memcpy(msg->buf, priv->data + offset, len);
                        }
                        memset(msg->buf + len, '\xff', msg->len - len);
                        debug_buffer(0, msg->buf, 1, msg->len, 0);
                } else if (len >= plat->offset_len) {
                        int i;

                        ptr = msg->buf;
                        for (i = 0; i < plat->offset_len; i++, len--)
                                offset = (offset << 8) | *ptr++;
                        debug(", set offset %x: ", offset);
                        debug_buffer(0, msg->buf, 1, msg->len, 0);
                        if (plat->test_mode == SIE_TEST_MODE_SINGLE_BYTE)
                                len = min(len, 1);

                        /* store offset for testing visibility */
                        priv->prev_offset = offset;

                        /* For testing, map offsets into our limited buffer.
                         * offset wraps every 256 bytes
                         */
                        offset &= 0xff;
                        debug("mapped offset to %x\n", offset);

                        if (offset + len > plat->size) {
                                int overflow = offset + len - plat->size;
                                int initial = len - overflow;

                                memcpy(priv->data + offset, ptr, initial);
                                memcpy(priv->data, ptr + initial, overflow);
                        } else {
                                memcpy(priv->data + offset, ptr, len);
                        }
                }
        }
        debug_buffer(0, priv->data, 1, 16, 0);

        return 0;
}

struct dm_i2c_ops sandbox_i2c_emul_ops = {
        .xfer = sandbox_i2c_eeprom_xfer,
};

static int sandbox_i2c_eeprom_ofdata_to_platdata(struct udevice *dev)
{
        struct sandbox_i2c_flash_plat_data *plat = dev_get_platdata(dev);

        plat->size = dev_read_u32_default(dev, "sandbox,size", 32);
        plat->filename = dev_read_string(dev, "sandbox,filename");
        if (!plat->filename) {
                debug("%s: No filename for device '%s'\n", __func__,
                      dev->name);
                return -EINVAL;
        }
        plat->test_mode = SIE_TEST_MODE_NONE;
        plat->offset_len = 1;
        plat->chip_addr_offset_mask = 0;

        return 0;
}

static int sandbox_i2c_eeprom_probe(struct udevice *dev)
{
        struct sandbox_i2c_flash_plat_data *plat = dev_get_platdata(dev);
        struct sandbox_i2c_flash *priv = dev_get_priv(dev);

        priv->data = calloc(1, plat->size);
        if (!priv->data)
                return -ENOMEM;

        return 0;
}

static int sandbox_i2c_eeprom_remove(struct udevice *dev)
{
        struct sandbox_i2c_flash *priv = dev_get_priv(dev);

        free(priv->data);

        return 0;
}

static const struct udevice_id sandbox_i2c_ids[] = {
        { .compatible = "sandbox,i2c-eeprom" },
        { }
};

U_BOOT_DRIVER(sandbox_i2c_emul) = {
        .name           = "sandbox_i2c_eeprom_emul",
        .id             = UCLASS_I2C_EMUL,
        .of_match       = sandbox_i2c_ids,
        .ofdata_to_platdata = sandbox_i2c_eeprom_ofdata_to_platdata,
        .probe          = sandbox_i2c_eeprom_probe,
        .remove         = sandbox_i2c_eeprom_remove,
        .priv_auto_alloc_size = sizeof(struct sandbox_i2c_flash),
        .platdata_auto_alloc_size = sizeof(struct sandbox_i2c_flash_plat_data),
        .ops            = &sandbox_i2c_emul_ops,
};