/*
 * Copyright (c) 2009-2015 Solarflare Communications Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * The views and conclusions contained in the software and documentation are
 * those of the authors and should not be interpreted as representing official
 * policies, either expressed or implied, of the FreeBSD Project.
 */

#include "efx.h"
#include "efx_impl.h"

#if EFSYS_OPT_BOOTCFG

/*
 * Maximum size of BOOTCFG block across all nics as understood by SFCgPXE.
 * A multiple of 0x100 so trailing 0xff characters don't contrinbute to the
 * checksum.
 */
#define BOOTCFG_MAX_SIZE 0x1000

#define DHCP_END (uint8_t)0xff
#define DHCP_PAD (uint8_t)0

static  __checkReturn           uint8_t
efx_bootcfg_csum(
        __in                    efx_nic_t *enp,
        __in_bcount(size)       caddr_t data,
        __in                    size_t size)
{
        _NOTE(ARGUNUSED(enp))

        unsigned int pos;
        uint8_t checksum = 0;

        for (pos = 0; pos < size; pos++)
                checksum += data[pos];
        return (checksum);
}

static  __checkReturn           efx_rc_t
efx_bootcfg_verify(
        __in                    efx_nic_t *enp,
        __in_bcount(size)       caddr_t data,
        __in                    size_t size,
        __out_opt               size_t *usedp)
{
        size_t offset = 0;
        size_t used = 0;
        efx_rc_t rc;

        /* Start parsing tags immediatly after the checksum */
        for (offset = 1; offset < size; ) {
                uint8_t tag;
                uint8_t length;

                /* Consume tag */
                tag = data[offset];
                if (tag == DHCP_END) {
                        offset++;
                        used = offset;
                        break;
                }
                if (tag == DHCP_PAD) {
                        offset++;
                        continue;
                }

                /* Consume length */
                if (offset + 1 >= size) {
                        rc = ENOSPC;
                        goto fail1;
                }
                length = data[offset + 1];

                /* Consume *length */
                if (offset + 1 + length >= size) {
                        rc = ENOSPC;
                        goto fail2;
                }

                offset += 2 + length;
                used = offset;
        }

        /* Checksum the entire sector, including bytes after any DHCP_END */
        if (efx_bootcfg_csum(enp, data, size) != 0) {
                rc = EINVAL;
                goto fail3;
        }

        if (usedp != NULL)
                *usedp = used;

        return (0);

fail3:
        EFSYS_PROBE(fail3);
fail2:
        EFSYS_PROBE(fail2);
fail1:
        EFSYS_PROBE1(fail1, efx_rc_t, rc);

        return (rc);
}

                                efx_rc_t
efx_bootcfg_read(
        __in                    efx_nic_t *enp,
        __out_bcount(size)      caddr_t data,
        __in                    size_t size)
{
        uint8_t *payload = NULL;
        size_t used_bytes;
        size_t sector_length;
        efx_rc_t rc;

        rc = efx_nvram_size(enp, EFX_NVRAM_BOOTROM_CFG, &sector_length);
        if (rc != 0)
                goto fail1;

        /*
         * We need to read the entire BOOTCFG area to ensure we read all the
         * tags, because legacy bootcfg sectors are not guaranteed to end with
         * a DHCP_END character. If the user hasn't supplied a sufficiently
         * large buffer then use our own buffer.
         */
        if (sector_length > BOOTCFG_MAX_SIZE)
                sector_length = BOOTCFG_MAX_SIZE;
        if (sector_length > size) {
                EFSYS_KMEM_ALLOC(enp->en_esip, sector_length, payload);
                if (payload == NULL) {
                        rc = ENOMEM;
                        goto fail2;
                }
        } else
                payload = (uint8_t *)data;

        if ((rc = efx_nvram_rw_start(enp, EFX_NVRAM_BOOTROM_CFG, NULL)) != 0)
                goto fail3;

        rc = efx_nvram_read_chunk(enp, EFX_NVRAM_BOOTROM_CFG, 0,
                                    (caddr_t)payload, sector_length);

        efx_nvram_rw_finish(enp, EFX_NVRAM_BOOTROM_CFG);

        if (rc != 0)
                goto fail4;

        /* Verify that the area is correctly formatted and checksummed */
        rc = efx_bootcfg_verify(enp, (caddr_t)payload, sector_length,
                                    &used_bytes);
        if (rc != 0 || used_bytes == 0) {
                payload[0] = (uint8_t)~DHCP_END;
                payload[1] = DHCP_END;
                used_bytes = 2;
        }

        EFSYS_ASSERT(used_bytes >= 2);  /* checksum and DHCP_END */
        EFSYS_ASSERT(used_bytes <= sector_length);

        /*
         * Legacy bootcfg sectors don't terminate with a DHCP_END character.
         * Modify the returned payload so it does. BOOTCFG_MAX_SIZE is by
         * definition large enough for any valid (per-port) bootcfg sector,
         * so reinitialise the sector if there isn't room for the character.
         */
        if (payload[used_bytes - 1] != DHCP_END) {
                if (used_bytes + 1 > sector_length) {
                        payload[0] = 0;
                        used_bytes = 1;
                }

                payload[used_bytes] = DHCP_END;
                ++used_bytes;
        }

        /*
         * Verify that the user supplied buffer is large enough for the
         * entire used bootcfg area, then copy into the user supplied buffer.
         */
        if (used_bytes > size) {
                rc = ENOSPC;
                goto fail5;
        }
        if (sector_length > size) {
                (void) memcpy(data, payload, used_bytes);
                EFSYS_KMEM_FREE(enp->en_esip, sector_length, payload);
        }

        /* Zero out the unused portion of the user buffer */
        if (used_bytes < size)
                (void) memset(data + used_bytes, 0, size - used_bytes);

        /*
         * The checksum includes trailing data after any DHCP_END character,
         * which we've just modified (by truncation or appending DHCP_END).
         */
        data[0] -= efx_bootcfg_csum(enp, data, size);

        return (0);

fail5:
        EFSYS_PROBE(fail5);
fail4:
        EFSYS_PROBE(fail4);
fail3:
        EFSYS_PROBE(fail3);

        if (sector_length > size)
                EFSYS_KMEM_FREE(enp->en_esip, sector_length, payload);
fail2:
        EFSYS_PROBE(fail2);
fail1:
        EFSYS_PROBE1(fail1, efx_rc_t, rc);

        return (rc);
}

                                efx_rc_t
efx_bootcfg_write(
        __in                    efx_nic_t *enp,
        __in_bcount(size)       caddr_t data,
        __in                    size_t size)
{
        uint8_t *chunk;
        uint8_t checksum;
        size_t sector_length;
        size_t chunk_length;
        size_t used_bytes;
        size_t offset;
        size_t remaining;
        efx_rc_t rc;

        rc = efx_nvram_size(enp, EFX_NVRAM_BOOTROM_CFG, &sector_length);
        if (rc != 0)
                goto fail1;

        if (sector_length > BOOTCFG_MAX_SIZE)
                sector_length = BOOTCFG_MAX_SIZE;

        if ((rc = efx_bootcfg_verify(enp, data, size, &used_bytes)) != 0)
                goto fail2;

        /* The caller *must* terminate their block with a DHCP_END character */
        EFSYS_ASSERT(used_bytes >= 2);          /* checksum and DHCP_END */
        if ((uint8_t)data[used_bytes - 1] != DHCP_END) {
                rc = ENOENT;
                goto fail3;
        }

        /* Check that the hardware has support for this much data */
        if (used_bytes > MIN(sector_length, BOOTCFG_MAX_SIZE)) {
                rc = ENOSPC;
                goto fail4;
        }

        rc = efx_nvram_rw_start(enp, EFX_NVRAM_BOOTROM_CFG, &chunk_length);
        if (rc != 0)
                goto fail5;

        EFSYS_KMEM_ALLOC(enp->en_esip, chunk_length, chunk);
        if (chunk == NULL) {
                rc = ENOMEM;
                goto fail6;
        }

        if ((rc = efx_nvram_erase(enp, EFX_NVRAM_BOOTROM_CFG)) != 0)
                goto fail7;

        /*
         * Write the entire sector_length bytes of data in chunks. Zero out
         * all data following the DHCP_END, and adjust the checksum
         */
        checksum = efx_bootcfg_csum(enp, data, used_bytes);
        for (offset = 0; offset < sector_length; offset += remaining) {
                remaining = MIN(chunk_length, sector_length - offset);

                /* Fill chunk */
                (void) memset(chunk, 0x0, chunk_length);
                if (offset < used_bytes)
                        (void) memcpy(chunk, data + offset,
                            MIN(remaining, used_bytes - offset));

                /* Adjust checksum */
                if (offset == 0)
                        chunk[0] -= checksum;

                if ((rc = efx_nvram_write_chunk(enp, EFX_NVRAM_BOOTROM_CFG,
                            offset, (caddr_t)chunk, remaining)) != 0)
                        goto fail8;
        }

        efx_nvram_rw_finish(enp, EFX_NVRAM_BOOTROM_CFG);

        EFSYS_KMEM_FREE(enp->en_esip, chunk_length, chunk);

        return (0);

fail8:
        EFSYS_PROBE(fail8);
fail7:
        EFSYS_PROBE(fail7);

        EFSYS_KMEM_FREE(enp->en_esip, chunk_length, chunk);
fail6:
        EFSYS_PROBE(fail6);

        efx_nvram_rw_finish(enp, EFX_NVRAM_BOOTROM_CFG);
fail5:
        EFSYS_PROBE(fail5);
fail4:
        EFSYS_PROBE(fail4);
fail3:
        EFSYS_PROBE(fail3);
fail2:
        EFSYS_PROBE(fail2);
fail1:
        EFSYS_PROBE1(fail1, efx_rc_t, rc);

        return (rc);
}

#endif  /* EFSYS_OPT_BOOTCFG */