/*
 * atmel_df_pow2.c - convert Atmel Dataflashes to Power of 2 mode
 *
 * Copyright 2009 Analog Devices Inc.
 *
 * Licensed under the 2-clause BSD.
 */

#include <common.h>
#include <exports.h>
#include <spi.h>
#include <linux/delay.h>

#define CMD_ID    0x9f
#define CMD_STAT  0xd7
#define CMD_CFG   0x3d

static int flash_cmd(struct spi_slave *slave, uchar cmd, uchar *buf, int len)
{
        buf[0] = cmd;
        return spi_xfer(slave, 8 * len, buf, buf, SPI_XFER_BEGIN | SPI_XFER_END);
}

static int flash_status(struct spi_slave *slave)
{
        uchar buf[2];
        if (flash_cmd(slave, CMD_STAT, buf, sizeof(buf)))
                return -1;
        return buf[1];
}

static int flash_set_pow2(struct spi_slave *slave)
{
        int ret;
        uchar buf[4];

        buf[1] = 0x2a;
        buf[2] = 0x80;
        buf[3] = 0xa6;

        ret = flash_cmd(slave, CMD_CFG, buf, sizeof(buf));
        if (ret)
                return ret;

        /* wait Tp, or 6 msec */
        udelay(6000);

        ret = flash_status(slave);
        if (ret == -1)
                return 1;

        return ret & 0x1 ? 0 : 1;
}

static int flash_check(struct spi_slave *slave)
{
        int ret;
        uchar buf[4];

        ret = flash_cmd(slave, CMD_ID, buf, sizeof(buf));
        if (ret)
                return ret;

        if (buf[1] != 0x1F) {
                printf("atmel flash not found (id[0] = %#x)\n", buf[1]);
                return 1;
        }

        if ((buf[2] >> 5) != 0x1) {
                printf("AT45 flash not found (id[0] = %#x)\n", buf[2]);
                return 2;
        }

        return 0;
}

static char *getline(void)
{
        static char buffer[100];
        char c;
        size_t i;

        i = 0;
        while (1) {
                buffer[i] = '\0';

                c = getc();

                switch (c) {
                case '\r':      /* Enter/Return key */
                case '\n':
                        puts("\n");
                        return buffer;

                case 0x03:      /* ^C - break */
                        return NULL;

                case 0x5F:
                case 0x08:      /* ^H  - backspace */
                case 0x7F:      /* DEL - backspace */
                        if (i) {
                                puts("\b \b");
                                i--;
                        }
                        break;

                default:
                        /* Ignore control characters */
                        if (c < 0x20)
                                break;
                        /* Queue up all other characters */
                        buffer[i++] = c;
                        printf("%c", c);
                        break;
                }
        }
}

int atmel_df_pow2(int argc, char *const argv[])
{
        /* Print the ABI version */
        app_startup(argv);
        if (XF_VERSION != get_version()) {
                printf("Expects ABI version %d\n", XF_VERSION);
                printf("Actual U-Boot ABI version %lu\n", get_version());
                printf("Can't run\n\n");
                return 1;
        }

        while (1) {
                struct spi_slave *slave;
                char *line, *p;
                int bus, cs, status;

                puts("\nenter the [BUS:]CS of the SPI flash: ");
                line = getline();

                /* CTRL+C */
                if (!line)
                        return 0;
                if (line[0] == '\0')
                        continue;

                bus = dectoul(line, &p);
                cs = bus;
                if (*p) {
                        if (*p == ':') {
                                ++p;
                                cs = dectoul(p, &p);
                        }
                        if (*p) {
                                puts("invalid format, please try again\n");
                                continue;
                        }
                } else
                        bus = 0;

                printf("\ngoing to work with dataflash at %i:%i\n", bus, cs);

                /* use a low speed -- it'll work with all devices, and
                 * speed here doesn't really matter.
                 */
                slave = spi_setup_slave(bus, cs, 1000, SPI_MODE_3);
                if (!slave) {
                        puts("unable to setup slave\n");
                        continue;
                }

                if (spi_claim_bus(slave)) {
                        spi_free_slave(slave);
                        continue;
                }

                if (flash_check(slave)) {
                        puts("no flash found\n");
                        goto done;
                }

                status = flash_status(slave);
                if (status == -1) {
                        puts("unable to read status register\n");
                        goto done;
                }
                if (status & 0x1) {
                        puts("flash is already in power-of-2 mode!\n");
                        goto done;
                }

                puts("are you sure you wish to set power-of-2 mode?\n");
                puts("this operation is permanent and irreversible\n");
                printf("enter YES to continue: ");
                line = getline();
                if (!line || strcmp(line, "YES"))
                        goto done;

                if (flash_set_pow2(slave)) {
                        puts("setting pow2 mode failed\n");
                        goto done;
                }

                puts(
                        "Configuration should be updated now.  You will have to\n"
                        "power cycle the part in order to finish the conversion.\n"
                );

 done:
                spi_release_bus(slave);
                spi_free_slave(slave);
        }
}