/*
 * avrdude - A Downloader/Uploader for AVR device programmers
 * Support for using spidev userspace drivers to communicate directly over SPI
 *
 * Copyright (C) 2013 Kevin Cuzner <kevin@kevincuzner.com>
 * Copyright (C) 2018 Ralf Ramsauer <ralf@vmexit.de>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Support for inversion of reset pin, Tim Chilton 02/05/2014
 * Review code, rebase to latest trunk, add linux/gpio.h support, Ralf Ramsauer 2018-09-07
 */


#include "ac_cfg.h"

#include "avrdude.h"
#include "libavrdude.h"

#include "linuxspi.h"

#if HAVE_LINUXSPI

/**
 * Linux Kernel SPI Drivers
 *
 * Copyright (C) 2006 SWAPP
 *      Andrea Paterniani <a.paterniani@swapp-eng.it>
 * Copyright (C) 2007 David Brownell (simplification, cleanup)
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <linux/types.h>
#include <linux/spi/spidev.h>
#include <linux/gpio.h>

#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>

#define LINUXSPI "linuxspi"

/*
 * Private data for this programmer.
 */
struct pdata {
  int disable_no_cs;
};

#define PDATA(pgm) ((struct pdata *)(pgm->cookie))

static int fd_spidev, fd_gpiochip, fd_linehandle;

/**
 * @brief Sends/receives a message in full duplex mode
 * @return -1 on failure, otherwise number of bytes sent/received
 */
static int linuxspi_spi_duplex(const PROGRAMMER *pgm, const unsigned char *tx, unsigned char *rx, int len) {
    struct spi_ioc_transfer tr;
    int ret;

    tr = (struct spi_ioc_transfer) {
        .tx_buf = (unsigned long)tx,
        .rx_buf = (unsigned long)rx,
        .len = len,
        .delay_usecs = 1,
        .speed_hz = 1.0 / pgm->bitclock,
        .bits_per_word = 8,
    };

    errno = 0;
    ret = ioctl(fd_spidev, SPI_IOC_MESSAGE(1), &tr);
    if (ret != len) {
        int ioctl_errno = errno;
        msg_error("\n");
        pmsg_error("unable to send SPI message");
        if (ioctl_errno)
            msg_error("%s", strerror(ioctl_errno));
        msg_error("\n");
    }

    return ret == -1? -1: 0;
}

static void linuxspi_setup(PROGRAMMER *pgm) {
  pgm->cookie = cfg_malloc("linuxspi_setup()", sizeof(struct pdata));
}

static void linuxspi_teardown(PROGRAMMER* pgm) {
  free(pgm->cookie);
}

static int linuxspi_reset_mcu(const PROGRAMMER *pgm, bool active) {
    struct gpiohandle_data data;
    int ret;

    /*
     * Set the reset state and keep it. The pin will be released and set back to
     * its initial value, once the fd_gpiochip is closed.
     */
    data.values[0] = active ^ !(pgm->pinno[PIN_AVR_RESET] & PIN_INVERSE);
    ret = ioctl(fd_linehandle, GPIOHANDLE_SET_LINE_VALUES_IOCTL, &data);
#ifdef GPIO_V2_LINE_SET_VALUES_IOCTL
    if (ret == -1) {
        struct gpio_v2_line_values val;

        val.mask = 1;
        val.bits = active ^ !(pgm->pinno[PIN_AVR_RESET] & PIN_INVERSE);

        ret = ioctl(fd_linehandle, GPIO_V2_LINE_SET_VALUES_IOCTL, &val);
    }
#endif
    if (ret == -1) {
        ret = -errno;
        pmsg_ext_error("unable to set GPIO line %d value: %s\n", pgm->pinno[PIN_AVR_RESET] & PIN_MASK, strerror(errno));
        return ret;
    }

    return 0;
}

static int linuxspi_open(PROGRAMMER *pgm, const char *pt) {
    const char *port_error =
      "unknown port specification, "
      "please use the format /dev/spidev:/dev/gpiochip[:resetno]\n";
    char port_default[] = "/dev/spidev0.0:/dev/gpiochip0";
    char *spidev, *gpiochip, *reset_pin;
    char *port = cfg_strdup("linuxspi_open()", pt);
    struct gpiohandle_request req;
    int ret;

    if (!strcmp(port, "unknown")) {
        port = port_default;
    }

    spidev = strtok(port, ":");
    if (!spidev) {
        pmsg_error("%s", port_error);
        return -1;
    }

    gpiochip = strtok(NULL, ":");
    if (!gpiochip) {
        pmsg_error("%s", port_error);
        return -1;
    }

    /* optional: override reset pin in configuration */
    reset_pin = strtok(NULL, ":");
    if (reset_pin)
        pgm->pinno[PIN_AVR_RESET] = strtoul(reset_pin, NULL, 0);

    strcpy(pgm->port, port);
    fd_spidev = open(pgm->port, O_RDWR);
    if (fd_spidev < 0) {
        pmsg_ext_error("unable to open the spidev device %s: %s\n", pgm->port, strerror(errno));
        return -1;
    }

    uint32_t mode = SPI_MODE_0;
    if (!PDATA(pgm)->disable_no_cs)
        mode |= SPI_NO_CS;

    ret = ioctl(fd_spidev, SPI_IOC_WR_MODE32, &mode);
    if (ret == -1) {
        int ioctl_errno = errno;
        pmsg_ext_error("unable to set SPI mode %02X on %s: %s\n", mode, spidev, strerror(errno));
        if(ioctl_errno == EINVAL && !PDATA(pgm)->disable_no_cs)
            pmsg_error("try -x disable_no_cs\n");
        goto close_spidev;
    }
    fd_gpiochip = open(gpiochip, 0);
    if (fd_gpiochip < 0) {
        pmsg_ext_error("unable to open the gpiochip %s: %s\n", gpiochip, strerror(errno));
        ret = -1;
        goto close_spidev;
    }

    strcpy(req.consumer_label, progname);
    req.lines = 1;
    req.lineoffsets[0] = pgm->pinno[PIN_AVR_RESET] & PIN_MASK;
    req.default_values[0] = !!(pgm->pinno[PIN_AVR_RESET] & PIN_INVERSE);
    req.flags = GPIOHANDLE_REQUEST_OUTPUT;

    ret = ioctl(fd_gpiochip, GPIO_GET_LINEHANDLE_IOCTL, &req);
    if (ret != -1)
        fd_linehandle = req.fd;
#ifdef GPIO_V2_GET_LINE_IOCTL
    if (ret == -1) {
        struct gpio_v2_line_request reqv2;

        memset(&reqv2, 0, sizeof(reqv2));
        reqv2.offsets[0] = pgm->pinno[PIN_AVR_RESET] & PIN_MASK;
        strncpy(reqv2.consumer, progname, sizeof(reqv2.consumer) - 1);
        reqv2.config.flags = GPIO_V2_LINE_FLAG_OUTPUT;
        reqv2.config.num_attrs = 1;
        reqv2.config.attrs[0].attr.id = GPIO_V2_LINE_ATTR_ID_OUTPUT_VALUES;
        reqv2.config.attrs[0].attr.values = !!(pgm->pinno[PIN_AVR_RESET] & PIN_INVERSE);
        reqv2.config.attrs[0].mask = 1;
        reqv2.num_lines = 1;

        ret = ioctl(fd_gpiochip, GPIO_V2_GET_LINE_IOCTL, &reqv2);
        if (ret != -1)
            fd_linehandle = reqv2.fd;
    }
#endif
    if (ret == -1) {
        ret = -errno;
        pmsg_ext_error("unable to get GPIO line %d. %s\n", pgm->pinno[PIN_AVR_RESET] & PIN_MASK, strerror(errno));
        goto close_gpiochip;
    }

    ret = linuxspi_reset_mcu(pgm, true);
    if (ret)
        goto close_out;

    if (pgm->baudrate != 0) {
        pmsg_warning("obsolete use of -b <clock> option for bit clock; use -B <clock>\n");
        pgm->bitclock = 1.0 / pgm->baudrate;
    }
    if (pgm->bitclock == 0) {
        pmsg_notice("defaulting bit clock to 200 kHz\n");
        pgm->bitclock = 5E-6; // 200 kHz - 5 µs
    }

    return 0;

close_out:
    close(fd_linehandle);
close_gpiochip:
    close(fd_gpiochip);
close_spidev:
    close(fd_spidev);
    return ret;
}

static void linuxspi_close(PROGRAMMER *pgm) {
    switch (pgm->exit_reset) {
    case EXIT_RESET_ENABLED:
        linuxspi_reset_mcu(pgm, true);
        break;

    case EXIT_RESET_DISABLED:
        linuxspi_reset_mcu(pgm, false);
        break;

    default:
        break;
    }

    close(fd_linehandle);
    close(fd_spidev);
    close(fd_gpiochip);
}

static void linuxspi_disable(const PROGRAMMER* pgm) {
}

static void linuxspi_enable(PROGRAMMER *pgm, const AVRPART *p) {
}

static void linuxspi_display(const PROGRAMMER* pgm, const char* p) {
}

static int linuxspi_initialize(const PROGRAMMER *pgm, const AVRPART *p) {
    int tries, ret;

    if (p->prog_modes & PM_TPI) {
        /* We do not support TPI. This is a dedicated SPI thing */
        pmsg_error("programmer " LINUXSPI " does not support TPI\n");
        return -1;
    }

    //enable programming on the part
    tries = 0;
    do
    {
        ret = pgm->program_enable(pgm, p);
        if (ret == 0 || ret == -1)
            break;
    } while(tries++ < 65);

    if (ret)
        pmsg_error("AVR device not responding\n");

    return ret;
}

static int linuxspi_cmd(const PROGRAMMER *pgm, const unsigned char *cmd, unsigned char *res)
{
    return linuxspi_spi_duplex(pgm, cmd, res, 4);
}

static int linuxspi_program_enable(const PROGRAMMER *pgm, const AVRPART *p) {
    unsigned char cmd[4], res[4];

    if (!p->op[AVR_OP_PGM_ENABLE]) {
        pmsg_error("program enable instruction not defined for part %s\n", p->desc);
        return -1;
    }

    memset(cmd, 0, sizeof(cmd));
    avr_set_bits(p->op[AVR_OP_PGM_ENABLE], cmd); //set the cmd
    pgm->cmd(pgm, cmd, res);

    if (res[2] != cmd[1]) {
        /*
         * From ATtiny441 datasheet:
         *
         * In some systems, the programmer can not guarantee that SCK is held low
         * during power-up. In this case, RESET must be given a positive pulse after
         * SCK has been set to '0'. The duration of the pulse must be at least t RST
         * plus two CPU clock cycles. See Table 25-5 on page 240 for definition of
         * minimum pulse width on RESET pin, t RST
         * 2. Wait for at least 20 ms and then enable serial programming by sending
         * the Programming Enable serial instruction to the SDO pin
         * 3. The serial programming instructions will not work if the communication
         * is out of synchronization. When in sync, the second byte (0x53) will echo
         * back when issuing the third byte of the Programming Enable instruction
         * ...
         * If the 0x53 did not echo back, give RESET a positive pulse and issue a
         * new Programming Enable command
         */
        if (linuxspi_reset_mcu(pgm, false))
            return -1;
        usleep(5);
        if (linuxspi_reset_mcu(pgm, true))
            return -1;
        usleep(20000);

        return -2;
    }

    return 0;
}

static int linuxspi_chip_erase(const PROGRAMMER *pgm, const AVRPART *p) {
    unsigned char cmd[4], res[4];

    if (!p->op[AVR_OP_CHIP_ERASE]) {
        pmsg_error("chip erase instruction not defined for part %s\n", p->desc);
        return -1;
    }

    memset(cmd, 0, sizeof(cmd));
    avr_set_bits(p->op[AVR_OP_CHIP_ERASE], cmd);
    pgm->cmd(pgm, cmd, res);
    usleep(p->chip_erase_delay);
    pgm->initialize(pgm, p);

    return 0;
}

static int linuxspi_parseexitspecs(PROGRAMMER *pgm, const char *sp) {
    char *cp, *s, *str = cfg_strdup("linuxspi_parseextitspecs()", sp);

    s = str;
    while ((cp = strtok(s, ","))) {
        s = NULL;
        if (!strcmp(cp, "reset")) {
            pgm->exit_reset = EXIT_RESET_ENABLED;
            continue;
        }
        if (!strcmp(cp, "noreset")) {
            pgm->exit_reset = EXIT_RESET_DISABLED;
            continue;
        }
        free(str);
        return -1;
    }

    free(str);
    return 0;
}

static int linuxspi_parseextparams(const PROGRAMMER *pgm, const LISTID extparms) {
  LNODEID ln;
  const char *extended_param;
  int rc = 0;

  for (ln = lfirst(extparms); ln; ln = lnext(ln)) {
    extended_param = ldata(ln);

    if (strcmp(extended_param, "disable_no_cs") == 0) {
      PDATA(pgm)->disable_no_cs = 1;
      continue;
    }

    pmsg_error("invalid extended parameter '%s'\n", extended_param);
    rc = -1;
  }

  return rc;
}

void linuxspi_initpgm(PROGRAMMER *pgm) {
    strcpy(pgm->type, LINUXSPI);

    pgm_fill_old_pins(pgm); // TODO to be removed if old pin data no longer needed

    /* mandatory functions */
    pgm->initialize     = linuxspi_initialize;
    pgm->display        = linuxspi_display;
    pgm->enable         = linuxspi_enable;
    pgm->disable        = linuxspi_disable;
    pgm->program_enable = linuxspi_program_enable;
    pgm->chip_erase     = linuxspi_chip_erase;
    pgm->cmd            = linuxspi_cmd;
    pgm->open           = linuxspi_open;
    pgm->close          = linuxspi_close;
    pgm->read_byte      = avr_read_byte_default;
    pgm->write_byte     = avr_write_byte_default;

    /* optional functions */
    pgm->setup          = linuxspi_setup;
    pgm->teardown       = linuxspi_teardown;
    pgm->parseexitspecs = linuxspi_parseexitspecs;
    pgm->parseextparams = linuxspi_parseextparams;
}

const char linuxspi_desc[] = "SPI using Linux spidev driver";

#else /* !HAVE_LINUXSPI */

void linuxspi_initpgm(PROGRAMMER *pgm) {
  pmsg_error("Linux SPI driver not available in this configuration\n");
}

const char linuxspi_desc[] = "SPI using Linux spidev driver (not available)";

#endif /* HAVE_LINUXSPI */