/*
 * (C) Copyright 2004, Psyent Corporation <www.psyent.com>
 * Scott McNutt <smcnutt@psyent.com>
 *
 * SPDX-License-Identifier:     GPL-2.0+
 */

#include <common.h>

#if defined(CONFIG_SYS_NIOS_EPCSBASE)
#include <command.h>
#include <asm/io.h>
#include <nios2-io.h>
#include <nios2-epcs.h>


/*-----------------------------------------------------------------------*/
#define SHORT_HELP\
        "epcs    - read/write Cyclone EPCS configuration device.\n"

#define LONG_HELP\
        "\n"\
        "epcs erase start [end]\n"\
        "    - erase sector start or sectors start through end.\n"\
        "epcs info\n"\
        "    - display EPCS device information.\n"\
        "epcs protect on | off\n"\
        "    - turn device protection on or off.\n"\
        "epcs read addr offset count\n"\
        "    - read count bytes from offset to addr.\n"\
        "epcs write addr offset count\n"\
        "    - write count bytes to offset from addr.\n"\
        "epcs verify addr offset count\n"\
        "    - verify count bytes at offset from addr."


/*-----------------------------------------------------------------------*/
/* Operation codes for serial configuration devices
 */
#define EPCS_WRITE_ENA          0x06    /* Write enable */
#define EPCS_WRITE_DIS          0x04    /* Write disable */
#define EPCS_READ_STAT          0x05    /* Read status */
#define EPCS_READ_BYTES         0x03    /* Read bytes */
#define EPCS_READ_ID            0xab    /* Read silicon id */
#define EPCS_WRITE_STAT         0x01    /* Write status */
#define EPCS_WRITE_BYTES        0x02    /* Write bytes */
#define EPCS_ERASE_BULK         0xc7    /* Erase entire device */
#define EPCS_ERASE_SECT         0xd8    /* Erase sector */

/* Device status register bits
 */
#define EPCS_STATUS_WIP         (1<<0)  /* Write in progress */
#define EPCS_STATUS_WEL         (1<<1)  /* Write enable latch */

/* Misc
 */
#define EPCS_TIMEOUT            100     /* 100 msec timeout */

static nios_spi_t *epcs = (nios_spi_t *)CONFIG_SYS_NIOS_EPCSBASE;

/***********************************************************************
 * Device access
 ***********************************************************************/
static int epcs_cs (int assert)
{
        ulong start;
        unsigned tmp;


        if (assert) {
                tmp = readl (&epcs->control);
                writel (tmp | NIOS_SPI_SSO, &epcs->control);
        } else {
                /* Let all bits shift out */
                start = get_timer (0);
                while ((readl (&epcs->status) & NIOS_SPI_TMT) == 0)
                        if (get_timer (start) > EPCS_TIMEOUT)
                                return (-1);
                tmp = readl (&epcs->control);
                writel (tmp & ~NIOS_SPI_SSO, &epcs->control);
        }
        return (0);
}

static int epcs_tx (unsigned char c)
{
        ulong start;

        start = get_timer (0);
        while ((readl (&epcs->status) & NIOS_SPI_TRDY) == 0)
                if (get_timer (start) > EPCS_TIMEOUT)
                        return (-1);
        writel (c, &epcs->txdata);
        return (0);
}

static int epcs_rx (void)
{
        ulong start;

        start = get_timer (0);
        while ((readl (&epcs->status) & NIOS_SPI_RRDY) == 0)
                if (get_timer (start) > EPCS_TIMEOUT)
                        return (-1);
        return (readl (&epcs->rxdata));
}

static unsigned char bitrev[] = {
        0x00, 0x08, 0x04, 0x0c, 0x02, 0x0a, 0x06, 0x0e,
        0x01, 0x09, 0x05, 0x0d, 0x03, 0x0b, 0x07, 0x0f
};

static unsigned char epcs_bitrev (unsigned char c)
{
        unsigned char val;

        val  = bitrev[c>>4];
        val |= bitrev[c & 0x0f]<<4;
        return (val);
}

static void epcs_rcv (unsigned char *dst, int len)
{
        while (len--) {
                epcs_tx (0);
                *dst++ = epcs_rx ();
        }
}

static void epcs_rrcv (unsigned char *dst, int len)
{
        while (len--) {
                epcs_tx (0);
                *dst++ = epcs_bitrev (epcs_rx ());
        }
}

static void epcs_snd (unsigned char *src, int len)
{
        while (len--) {
                epcs_tx (*src++);
                epcs_rx ();
        }
}

static void epcs_rsnd (unsigned char *src, int len)
{
        while (len--) {
                epcs_tx (epcs_bitrev (*src++));
                epcs_rx ();
        }
}

static void epcs_wr_enable (void)
{
        epcs_cs (1);
        epcs_tx (EPCS_WRITE_ENA);
        epcs_rx ();
        epcs_cs (0);
}

static unsigned char epcs_status_rd (void)
{
        unsigned char status;

        epcs_cs (1);
        epcs_tx (EPCS_READ_STAT);
        epcs_rx ();
        epcs_tx (0);
        status = epcs_rx ();
        epcs_cs (0);
        return (status);
}

static void epcs_status_wr (unsigned char status)
{
        epcs_wr_enable ();
        epcs_cs (1);
        epcs_tx (EPCS_WRITE_STAT);
        epcs_rx ();
        epcs_tx (status);
        epcs_rx ();
        epcs_cs (0);
        return;
}

/***********************************************************************
 * Device information
 ***********************************************************************/

static struct epcs_devinfo_t devinfo[] = {
        { "EPCS1 ", 0x10, 17, 4, 15, 8, 0x0c },
        { "EPCS4 ", 0x12, 19, 8, 16, 8, 0x1c },
        { "EPCS16", 0x14, 21, 32, 16, 8, 0x1c },
        { "EPCS64", 0x16, 23,128, 16, 8, 0x1c },
        { 0, 0, 0, 0, 0, 0 }
};

int epcs_reset (void)
{
        /* When booting from an epcs controller, the epcs bootrom
         * code may leave the slave select in an asserted state.
         * This causes two problems: (1) The initial epcs access
         * will fail -- not a big deal, and (2) a software reset
         * will cause the bootrom code to hang since it does not
         * ensure the select is negated prior to first access -- a
         * big deal. Here we just negate chip select and everything
         * gets better :-)
         */
        epcs_cs (0); /* Negate chip select */
        return (0);
}

epcs_devinfo_t *epcs_dev_find (void)
{
        unsigned char buf[4];
        unsigned char id;
        int i;
        struct epcs_devinfo_t *dev = NULL;

        /* Read silicon id requires 3 "dummy bytes" before it's put
         * on the wire.
         */
        buf[0] = EPCS_READ_ID;
        buf[1] = 0;
        buf[2] = 0;
        buf[3] = 0;

        epcs_cs (1);
        epcs_snd (buf,4);
        epcs_rcv (buf,1);
        if (epcs_cs (0) == -1)
                return (NULL);
        id = buf[0];

        /* Find the info struct */
        i = 0;
        while (devinfo[i].name) {
                if (id == devinfo[i].id) {
                        dev = &devinfo[i];
                        break;
                }
                i++;
        }

        return (dev);
}

/***********************************************************************
 * Misc Utilities
 ***********************************************************************/
int epcs_cfgsz (void)
{
        int sz = 0;
        unsigned char buf[128];
        unsigned char *p;
        struct epcs_devinfo_t *dev = epcs_dev_find ();

        if (!dev)
                return (-1);

        /* Read in the first 128 bytes of the device */
        buf[0] = EPCS_READ_BYTES;
        buf[1] = 0;
        buf[2] = 0;
        buf[3] = 0;

        epcs_cs (1);
        epcs_snd (buf,4);
        epcs_rrcv (buf, sizeof(buf));
        epcs_cs (0);

        /* Search for the starting 0x6a which is followed by the
         * 4-byte 'register' and 4-byte bit-count.
         */
        p = buf;
        while (p < buf + sizeof(buf)-8) {
                if ( *p == 0x6a ) {
                        /* Point to bit count and extract */
                        p += 5;
                        sz = *p++;
                        sz |= *p++ << 8;
                        sz |= *p++ << 16;
                        sz |= *p++ << 24;
                        /* Convert to byte count */
                        sz += 7;
                        sz >>= 3;
                } else if (*p == 0xff) {
                        /* 0xff is ok ... just skip */
                        p++;
                        continue;
                } else {
                        /* Not 0xff or 0x6a ... something's not
                         * right ... report 'unknown' (sz=0).
                         */
                        break;
                }
        }
        return (sz);
}

int epcs_erase (unsigned start, unsigned end)
{
        unsigned off, sectsz;
        unsigned char buf[4];
        struct epcs_devinfo_t *dev = epcs_dev_find ();

        if (!dev || (start>end))
                return (-1);

        /* Erase the requested sectors. An address is required
         * that lies within the requested sector -- we'll just
         * use the first address in the sector.
         */
        printf ("epcs erasing sector %d ", start);
        if (start != end)
                printf ("to %d ", end);
        sectsz = (1 << dev->sz_sect);
        while (start <= end) {
                off = start * sectsz;
                start++;

                buf[0] = EPCS_ERASE_SECT;
                buf[1] = off >> 16;
                buf[2] = off >> 8;
                buf[3] = off;

                epcs_wr_enable ();
                epcs_cs (1);
                epcs_snd (buf,4);
                epcs_cs (0);

                printf ("."); /* Some user feedback */

                /* Wait for erase to complete */
                while (epcs_status_rd() & EPCS_STATUS_WIP)
                        ;
        }
        printf (" done.\n");
        return (0);
}

int epcs_read (ulong addr, ulong off, ulong cnt)
{
        unsigned char buf[4];
        struct epcs_devinfo_t *dev = epcs_dev_find ();

        if (!dev)
                return (-1);

        buf[0] = EPCS_READ_BYTES;
        buf[1] = off >> 16;
        buf[2] = off >> 8;
        buf[3] = off;

        epcs_cs (1);
        epcs_snd (buf,4);
        epcs_rrcv ((unsigned char *)addr, cnt);
        epcs_cs (0);

        return (0);
}

int epcs_write (ulong addr, ulong off, ulong cnt)
{
        ulong wrcnt;
        unsigned pgsz;
        unsigned char buf[4];
        struct epcs_devinfo_t *dev = epcs_dev_find ();

        if (!dev)
                return (-1);

        pgsz = (1<<dev->sz_page);
        while (cnt) {
                if (off % pgsz)
                        wrcnt = pgsz - (off % pgsz);
                else
                        wrcnt = pgsz;
                wrcnt = (wrcnt > cnt) ? cnt : wrcnt;

                buf[0] = EPCS_WRITE_BYTES;
                buf[1] = off >> 16;
                buf[2] = off >> 8;
                buf[3] = off;

                epcs_wr_enable ();
                epcs_cs (1);
                epcs_snd (buf,4);
                epcs_rsnd ((unsigned char *)addr, wrcnt);
                epcs_cs (0);

                /* Wait for write to complete */
                while (epcs_status_rd() & EPCS_STATUS_WIP)
                        ;

                cnt -= wrcnt;
                off += wrcnt;
                addr += wrcnt;
        }

        return (0);
}

int epcs_verify (ulong addr, ulong off, ulong cnt, ulong *err)
{
        ulong rdcnt;
        unsigned char buf[256];
        unsigned char *start,*end;
        int i;

        start = end = (unsigned char *)addr;
        while (cnt) {
                rdcnt = (cnt>sizeof(buf)) ? sizeof(buf) : cnt;
                epcs_read ((ulong)buf, off, rdcnt);
                for (i=0; i<rdcnt; i++) {
                        if (*end != buf[i]) {
                                *err = end - start;
                                return(-1);
                        }
                        end++;
                }
                cnt -= rdcnt;
                off += rdcnt;
        }
        return (0);
}

static int epcs_sect_erased (int sect, unsigned *offset,
                struct epcs_devinfo_t *dev)
{
        unsigned char buf[128];
        unsigned off, end;
        unsigned sectsz;
        int i;

        sectsz = (1 << dev->sz_sect);
        off = sectsz * sect;
        end = off + sectsz;

        while (off < end) {
                epcs_read ((ulong)buf, off, sizeof(buf));
                for (i=0; i < sizeof(buf); i++) {
                        if (buf[i] != 0xff) {
                                *offset = off + i;
                                return (0);
                        }
                }
                off += sizeof(buf);
        }
        return (1);
}


/***********************************************************************
 * Commands
 ***********************************************************************/
static
void do_epcs_info (struct epcs_devinfo_t *dev, int argc, char * const argv[])
{
        int i;
        unsigned char stat;
        unsigned tmp;
        int erased;

        /* Basic device info */
        printf ("%s: %d kbytes (%d sectors x %d kbytes,"
                " %d bytes/page)\n",
                dev->name, 1 << (dev->size-10),
                dev->num_sects, 1 << (dev->sz_sect-10),
                1 << dev->sz_page );

        /* Status -- for now protection is all-or-nothing */
        stat = epcs_status_rd();
        printf ("status: 0x%02x (WIP:%d, WEL:%d, PROT:%s)\n",
                stat,
                (stat & EPCS_STATUS_WIP) ? 1 : 0,
                (stat & EPCS_STATUS_WEL) ? 1 : 0,
                (stat & dev->prot_mask) ? "on" : "off" );

        /* Configuration  */
        tmp = epcs_cfgsz ();
        if (tmp) {
                printf ("config: 0x%06x (%d) bytes\n", tmp, tmp );
        } else {
                printf ("config: unknown\n" );
        }

        /* Sector info */
        for (i=0; (i < dev->num_sects) && (argc > 1); i++) {
                erased = epcs_sect_erased (i, &tmp, dev);
                if ((i & 0x03) == 0) printf ("\n");
                printf ("%4d: %07x ",
                        i, i*(1<<dev->sz_sect) );
                if (erased)
                        printf ("E ");
                else
                        printf ("  ");
        }
        printf ("\n");

        return;
}

static
void do_epcs_erase (struct epcs_devinfo_t *dev, int argc, char * const argv[])
{
        unsigned start,end;

        if ((argc < 3) || (argc > 4)) {
                printf ("USAGE: epcs erase sect [end]\n");
                return;
        }
        if ((epcs_status_rd() & dev->prot_mask) != 0) {
                printf ( "epcs: device protected.\n");
                return;
        }

        start = simple_strtoul (argv[2], NULL, 10);
        if (argc > 3)
                end = simple_strtoul (argv[3], NULL, 10);
        else
                end = start;
        if ((start >= dev->num_sects) || (start > end)) {
                printf ("epcs: invalid sector range: [%d:%d]\n",
                        start, end );
                return;
        }

        epcs_erase (start, end);

        return;
}

static
void do_epcs_protect (struct epcs_devinfo_t *dev, int argc, char * const argv[])
{
        unsigned char stat;

        /* For now protection is all-or-nothing to keep things
         * simple. The protection bits don't map in a linear
         * fashion ... and we would rather protect the bottom
         * of the device since it contains the config data and
         * leave the top unprotected for app use. But unfortunately
         * protection works from top-to-bottom so it does
         * really help very much from a software app point-of-view.
         */
        if (argc < 3) {
                printf ("USAGE: epcs protect on | off\n");
                return;
        }
        if (!dev)
                return;

        /* Protection on/off is just a matter of setting/clearing
         * all protection bits in the status register.
         */
        stat = epcs_status_rd ();
        if (strcmp ("on", argv[2]) == 0) {
                stat |= dev->prot_mask;
        } else if (strcmp ("off", argv[2]) == 0 ) {
                stat &= ~dev->prot_mask;
        } else {
                printf ("epcs: unknown protection: %s\n", argv[2]);
                return;
        }
        epcs_status_wr (stat);
        return;
}

static
void do_epcs_read (struct epcs_devinfo_t *dev, int argc, char * const argv[])
{
        ulong addr,off,cnt;
        ulong sz;

        if (argc < 5) {
                printf ("USAGE: epcs read addr offset count\n");
                return;
        }

        sz = 1 << dev->size;
        addr = simple_strtoul (argv[2], NULL, 16);
        off  = simple_strtoul (argv[3], NULL, 16);
        cnt  = simple_strtoul (argv[4], NULL, 16);
        if (off > sz) {
                printf ("offset is greater than device size"
                        "... aborting.\n");
                return;
        }
        if ((off + cnt) > sz) {
                printf ("request exceeds device size"
                        "... truncating.\n");
                cnt = sz - off;
        }
        printf ("epcs: read %08lx <- %06lx (0x%lx bytes)\n",
                        addr, off, cnt);
        epcs_read (addr, off, cnt);

        return;
}

static
void do_epcs_write (struct epcs_devinfo_t *dev, int argc, char * const argv[])
{
        ulong addr,off,cnt;
        ulong sz;
        ulong err;

        if (argc < 5) {
                printf ("USAGE: epcs write addr offset count\n");
                return;
        }
        if ((epcs_status_rd() & dev->prot_mask) != 0) {
                printf ( "epcs: device protected.\n");
                return;
        }

        sz = 1 << dev->size;
        addr = simple_strtoul (argv[2], NULL, 16);
        off  = simple_strtoul (argv[3], NULL, 16);
        cnt  = simple_strtoul (argv[4], NULL, 16);
        if (off > sz) {
                printf ("offset is greater than device size"
                        "... aborting.\n");
                return;
        }
        if ((off + cnt) > sz) {
                printf ("request exceeds device size"
                        "... truncating.\n");
                cnt = sz - off;
        }
        printf ("epcs: write %08lx -> %06lx (0x%lx bytes)\n",
                        addr, off, cnt);
        epcs_write (addr, off, cnt);
        if (epcs_verify (addr, off, cnt, &err) != 0)
                printf ("epcs: write error at offset %06lx\n", err);

        return;
}

static
void do_epcs_verify (struct epcs_devinfo_t *dev, int argc, char * const argv[])
{
        ulong addr,off,cnt;
        ulong sz;
        ulong err;

        if (argc < 5) {
                printf ("USAGE: epcs verify addr offset count\n");
                return;
        }

        sz = 1 << dev->size;
        addr = simple_strtoul (argv[2], NULL, 16);
        off  = simple_strtoul (argv[3], NULL, 16);
        cnt  = simple_strtoul (argv[4], NULL, 16);
        if (off > sz) {
                printf ("offset is greater than device size"
                        "... aborting.\n");
                return;
        }
        if ((off + cnt) > sz) {
                printf ("request exceeds device size"
                        "... truncating.\n");
                cnt = sz - off;
        }
        printf ("epcs: verify %08lx -> %06lx (0x%lx bytes)\n",
                        addr, off, cnt);
        if (epcs_verify (addr, off, cnt, &err) != 0)
                printf ("epcs: verify error at offset %06lx\n", err);

        return;
}

/*-----------------------------------------------------------------------*/
int do_epcs (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
        int len;
        struct epcs_devinfo_t *dev = epcs_dev_find ();

        if (!dev) {
                printf ("epcs: device not found.\n");
                return (-1);
        }

        if (argc < 2) {
                do_epcs_info (dev, argc, argv);
                return (0);
        }

        len = strlen (argv[1]);
        if (strncmp ("info", argv[1], len) == 0) {
                do_epcs_info (dev, argc, argv);
        } else if (strncmp ("erase", argv[1], len) == 0) {
                do_epcs_erase (dev, argc, argv);
        } else if (strncmp ("protect", argv[1], len) == 0) {
                do_epcs_protect (dev, argc, argv);
        } else if (strncmp ("read", argv[1], len) == 0) {
                do_epcs_read (dev, argc, argv);
        } else if (strncmp ("write", argv[1], len) == 0) {
                do_epcs_write (dev, argc, argv);
        } else if (strncmp ("verify", argv[1], len) == 0) {
                do_epcs_verify (dev, argc, argv);
        } else {
                printf ("epcs: unknown operation: %s\n", argv[1]);
        }

        return (0);
}

/*-----------------------------------------------------------------------*/


U_BOOT_CMD( epcs, 5, 0, do_epcs, SHORT_HELP, LONG_HELP );

#endif /* CONFIG_NIOS_EPCS */