/*
 * Chromium OS cros_ec driver - SPI interface
 *
 * Copyright (c) 2012 The Chromium OS Authors.
 *
 * SPDX-License-Identifier:     GPL-2.0+
 */

/*
 * The Matrix Keyboard Protocol driver handles talking to the keyboard
 * controller chip. Mostly this is for keyboard functions, but some other
 * things have slipped in, so we provide generic services to talk to the
 * KBC.
 */

#include <common.h>
#include <cros_ec.h>
#include <dm.h>
#include <errno.h>
#include <spi.h>

DECLARE_GLOBAL_DATA_PTR;

int cros_ec_spi_packet(struct udevice *udev, int out_bytes, int in_bytes)
{
        struct cros_ec_dev *dev = dev_get_uclass_priv(udev);
        struct spi_slave *slave = dev_get_parent_priv(dev->dev);
        ulong start;
        uint8_t byte;
        int rv;

        /* Do the transfer */
        if (spi_claim_bus(slave)) {
                debug("%s: Cannot claim SPI bus\n", __func__);
                return -1;
        }

        rv = spi_xfer(slave, out_bytes * 8, dev->dout, NULL, SPI_XFER_BEGIN);
        if (rv)
                goto done;
        start = get_timer(0);
        while (1) {
                rv = spi_xfer(slave, 8, NULL, &byte, 0);
                if (byte == SPI_PREAMBLE_END_BYTE)
                        break;
                if (rv)
                        goto done;
                if (get_timer(start) > 100) {
                        rv = -ETIMEDOUT;
                        goto done;
                }
        }

        rv = spi_xfer(slave, in_bytes * 8, NULL, dev->din, 0);
done:
        spi_xfer(slave, 0, NULL, NULL, SPI_XFER_END);
        spi_release_bus(slave);

        if (rv) {
                debug("%s: Cannot complete SPI transfer\n", __func__);
                return -1;
        }

        return in_bytes;
}

/**
 * Send a command to a LPC CROS_EC device and return the reply.
 *
 * The device's internal input/output buffers are used.
 *
 * @param dev           CROS_EC device
 * @param cmd           Command to send (EC_CMD_...)
 * @param cmd_version   Version of command to send (EC_VER_...)
 * @param dout          Output data (may be NULL If dout_len=0)
 * @param dout_len      Size of output data in bytes
 * @param dinp          Returns pointer to response data. This will be
 *                      untouched unless we return a value > 0.
 * @param din_len       Maximum size of response in bytes
 * @return number of bytes in response, or -1 on error
 */
int cros_ec_spi_command(struct udevice *udev, uint8_t cmd, int cmd_version,
                     const uint8_t *dout, int dout_len,
                     uint8_t **dinp, int din_len)
{
        struct cros_ec_dev *dev = dev_get_uclass_priv(udev);
        struct spi_slave *slave = dev_get_parent_priv(dev->dev);
        int in_bytes = din_len + 4;     /* status, length, checksum, trailer */
        uint8_t *out;
        uint8_t *p;
        int csum, len;
        int rv;

        if (dev->protocol_version != 2) {
                debug("%s: Unsupported EC protcol version %d\n",
                      __func__, dev->protocol_version);
                return -1;
        }

        /*
         * Sanity-check input size to make sure it plus transaction overhead
         * fits in the internal device buffer.
         */
        if (in_bytes > sizeof(dev->din)) {
                debug("%s: Cannot receive %d bytes\n", __func__, din_len);
                return -1;
        }

        /* We represent message length as a byte */
        if (dout_len > 0xff) {
                debug("%s: Cannot send %d bytes\n", __func__, dout_len);
                return -1;
        }

        /*
         * Clear input buffer so we don't get false hits for MSG_HEADER
         */
        memset(dev->din, '\0', in_bytes);

        if (spi_claim_bus(slave)) {
                debug("%s: Cannot claim SPI bus\n", __func__);
                return -1;
        }

        out = dev->dout;
        out[0] = EC_CMD_VERSION0 + cmd_version;
        out[1] = cmd;
        out[2] = (uint8_t)dout_len;
        memcpy(out + 3, dout, dout_len);
        csum = cros_ec_calc_checksum(out, 3)
               + cros_ec_calc_checksum(dout, dout_len);
        out[3 + dout_len] = (uint8_t)csum;

        /*
         * Send output data and receive input data starting such that the
         * message body will be dword aligned.
         */
        p = dev->din + sizeof(int64_t) - 2;
        len = dout_len + 4;
        cros_ec_dump_data("out", cmd, out, len);
        rv = spi_xfer(slave, max(len, in_bytes) * 8, out, p,
                      SPI_XFER_BEGIN | SPI_XFER_END);

        spi_release_bus(slave);

        if (rv) {
                debug("%s: Cannot complete SPI transfer\n", __func__);
                return -1;
        }

        len = min((int)p[1], din_len);
        cros_ec_dump_data("in", -1, p, len + 3);

        /* Response code is first byte of message */
        if (p[0] != EC_RES_SUCCESS) {
                printf("%s: Returned status %d\n", __func__, p[0]);
                return -(int)(p[0]);
        }

        /* Check checksum */
        csum = cros_ec_calc_checksum(p, len + 2);
        if (csum != p[len + 2]) {
                debug("%s: Invalid checksum rx %#02x, calced %#02x\n", __func__,
                      p[2 + len], csum);
                return -1;
        }

        /* Anything else is the response data */
        *dinp = p + 2;

        return len;
}

static int cros_ec_probe(struct udevice *dev)
{
        return cros_ec_register(dev);
}

static struct dm_cros_ec_ops cros_ec_ops = {
        .packet = cros_ec_spi_packet,
        .command = cros_ec_spi_command,
};

static const struct udevice_id cros_ec_ids[] = {
        { .compatible = "google,cros-ec-spi" },
        { }
};

U_BOOT_DRIVER(cros_ec_spi) = {
        .name           = "cros_ec_spi",
        .id             = UCLASS_CROS_EC,
        .of_match       = cros_ec_ids,
        .probe          = cros_ec_probe,
        .ops            = &cros_ec_ops,
};