/*
* Filename: config.c
*
*
* Authors: Joshua Morris <josh.h.morris@us.ibm.com>
*       Philip Kelleher <pjk1939@linux.vnet.ibm.com>
*
* (C) Copyright 2013 IBM Corporation
*
* 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
*/

#include <linux/types.h>
#include <linux/crc32.h>
#include <linux/swab.h>

#include "rsxx_priv.h"
#include "rsxx_cfg.h"

static void initialize_config(struct rsxx_card_cfg *cfg)
{
        cfg->hdr.version = RSXX_CFG_VERSION;

        cfg->data.block_size        = RSXX_HW_BLK_SIZE;
        cfg->data.stripe_size       = RSXX_HW_BLK_SIZE;
        cfg->data.vendor_id         = RSXX_VENDOR_ID_IBM;
        cfg->data.cache_order       = (-1);
        cfg->data.intr_coal.mode    = RSXX_INTR_COAL_DISABLED;
        cfg->data.intr_coal.count   = 0;
        cfg->data.intr_coal.latency = 0;
}

static u32 config_data_crc32(struct rsxx_card_cfg *cfg)
{
        /*
         * Return the compliment of the CRC to ensure compatibility
         * (i.e. this is how early rsxx drivers did it.)
         */

        return ~crc32(~0, &cfg->data, sizeof(cfg->data));
}


/*----------------- Config Byte Swap Functions -------------------*/
static void config_hdr_be_to_cpu(struct card_cfg_hdr *hdr)
{
        hdr->version = be32_to_cpu((__force __be32) hdr->version);
        hdr->crc     = be32_to_cpu((__force __be32) hdr->crc);
}

static void config_hdr_cpu_to_be(struct card_cfg_hdr *hdr)
{
        hdr->version = (__force u32) cpu_to_be32(hdr->version);
        hdr->crc     = (__force u32) cpu_to_be32(hdr->crc);
}

static void config_data_swab(struct rsxx_card_cfg *cfg)
{
        u32 *data = (u32 *) &cfg->data;
        int i;

        for (i = 0; i < (sizeof(cfg->data) / 4); i++)
                data[i] = swab32(data[i]);
}

static void config_data_le_to_cpu(struct rsxx_card_cfg *cfg)
{
        u32 *data = (u32 *) &cfg->data;
        int i;

        for (i = 0; i < (sizeof(cfg->data) / 4); i++)
                data[i] = le32_to_cpu((__force __le32) data[i]);
}

static void config_data_cpu_to_le(struct rsxx_card_cfg *cfg)
{
        u32 *data = (u32 *) &cfg->data;
        int i;

        for (i = 0; i < (sizeof(cfg->data) / 4); i++)
                data[i] = (__force u32) cpu_to_le32(data[i]);
}


/*----------------- Config Operations ------------------*/
static int rsxx_save_config(struct rsxx_cardinfo *card)
{
        struct rsxx_card_cfg cfg;
        int st;

        memcpy(&cfg, &card->config, sizeof(cfg));

        if (unlikely(cfg.hdr.version != RSXX_CFG_VERSION)) {
                dev_err(CARD_TO_DEV(card),
                        "Cannot save config with invalid version %d\n",
                        cfg.hdr.version);
                return -EINVAL;
        }

        /* Convert data to little endian for the CRC calculation. */
        config_data_cpu_to_le(&cfg);

        cfg.hdr.crc = config_data_crc32(&cfg);

        /*
         * Swap the data from little endian to big endian so it can be
         * stored.
         */
        config_data_swab(&cfg);
        config_hdr_cpu_to_be(&cfg.hdr);

        st = rsxx_creg_write(card, CREG_ADD_CONFIG, sizeof(cfg), &cfg, 1);
        if (st)
                return st;

        return 0;
}

int rsxx_load_config(struct rsxx_cardinfo *card)
{
        int st;
        u32 crc;

        st = rsxx_creg_read(card, CREG_ADD_CONFIG, sizeof(card->config),
                                &card->config, 1);
        if (st) {
                dev_err(CARD_TO_DEV(card),
                        "Failed reading card config.\n");
                return st;
        }

        config_hdr_be_to_cpu(&card->config.hdr);

        if (card->config.hdr.version == RSXX_CFG_VERSION) {
                /*
                 * We calculate the CRC with the data in little endian, because
                 * early drivers did not take big endian CPUs into account.
                 * The data is always stored in big endian, so we need to byte
                 * swap it before calculating the CRC.
                 */

                config_data_swab(&card->config);

                /* Check the CRC */
                crc = config_data_crc32(&card->config);
                if (crc != card->config.hdr.crc) {
                        dev_err(CARD_TO_DEV(card),
                                "Config corruption detected!\n");
                        dev_info(CARD_TO_DEV(card),
                                "CRC (sb x%08x is x%08x)\n",
                                card->config.hdr.crc, crc);
                        return -EIO;
                }

                /* Convert the data to CPU byteorder */
                config_data_le_to_cpu(&card->config);

        } else if (card->config.hdr.version != 0) {
                dev_err(CARD_TO_DEV(card),
                        "Invalid config version %d.\n",
                        card->config.hdr.version);
                /*
                 * Config version changes require special handling from the
                 * user
                 */
                return -EINVAL;
        } else {
                dev_info(CARD_TO_DEV(card),
                        "Initializing card configuration.\n");
                initialize_config(&card->config);
                st = rsxx_save_config(card);
                if (st)
                        return st;
        }

        card->config_valid = 1;

        dev_dbg(CARD_TO_DEV(card), "version:     x%08x\n",
                card->config.hdr.version);
        dev_dbg(CARD_TO_DEV(card), "crc:         x%08x\n",
                card->config.hdr.crc);
        dev_dbg(CARD_TO_DEV(card), "block_size:  x%08x\n",
                card->config.data.block_size);
        dev_dbg(CARD_TO_DEV(card), "stripe_size: x%08x\n",
                card->config.data.stripe_size);
        dev_dbg(CARD_TO_DEV(card), "vendor_id:   x%08x\n",
                card->config.data.vendor_id);
        dev_dbg(CARD_TO_DEV(card), "cache_order: x%08x\n",
                card->config.data.cache_order);
        dev_dbg(CARD_TO_DEV(card), "mode:        x%08x\n",
                card->config.data.intr_coal.mode);
        dev_dbg(CARD_TO_DEV(card), "count:       x%08x\n",
                card->config.data.intr_coal.count);
        dev_dbg(CARD_TO_DEV(card), "latency:     x%08x\n",
                 card->config.data.intr_coal.latency);

        return 0;
}