/******************************************************************************
 *
 * This file is provided under a dual BSD/GPLv2 license.  When using or
 * redistributing this file, you may do so under either license.
 *
 * GPL LICENSE SUMMARY
 *
 * Copyright(c) 2008 - 2014 Intel Corporation. All rights reserved.
 * Copyright(c) 2018 Intel Corporation
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * 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.
 *
 * The full GNU General Public License is included in this distribution
 * in the file called COPYING.
 *
 * Contact Information:
 *  Intel Linux Wireless <linuxwifi@intel.com>
 * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
 *
 * BSD LICENSE
 *
 * Copyright(c) 2005 - 2014 Intel Corporation. All rights reserved.
 * Copyright(c) 2018 Intel Corporation
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *  * Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *  * 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.
 *  * Neither the name Intel Corporation nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * 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.
 *****************************************************************************/
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/export.h>

#include "iwl-drv.h"
#include "iwl-debug.h"
#include "iwl-eeprom-read.h"
#include "iwl-io.h"
#include "iwl-prph.h"
#include "iwl-csr.h"

/*
 * EEPROM access time values:
 *
 * Driver initiates EEPROM read by writing byte address << 1 to CSR_EEPROM_REG.
 * Driver then polls CSR_EEPROM_REG for CSR_EEPROM_REG_READ_VALID_MSK (0x1).
 * When polling, wait 10 uSec between polling loops, up to a maximum 5000 uSec.
 * Driver reads 16-bit value from bits 31-16 of CSR_EEPROM_REG.
 */
#define IWL_EEPROM_ACCESS_TIMEOUT       5000 /* uSec */

#define IWL_EEPROM_SEM_TIMEOUT          10   /* microseconds */
#define IWL_EEPROM_SEM_RETRY_LIMIT      1000 /* number of attempts (not time) */


/*
 * The device's EEPROM semaphore prevents conflicts between driver and uCode
 * when accessing the EEPROM; each access is a series of pulses to/from the
 * EEPROM chip, not a single event, so even reads could conflict if they
 * weren't arbitrated by the semaphore.
 */

#define EEPROM_SEM_TIMEOUT 10           /* milliseconds */
#define EEPROM_SEM_RETRY_LIMIT 1000     /* number of attempts (not time) */

static int iwl_eeprom_acquire_semaphore(struct iwl_trans *trans)
{
        u16 count;
        int ret;

        for (count = 0; count < EEPROM_SEM_RETRY_LIMIT; count++) {
                /* Request semaphore */
                iwl_set_bit(trans, CSR_HW_IF_CONFIG_REG,
                            CSR_HW_IF_CONFIG_REG_BIT_EEPROM_OWN_SEM);

                /* See if we got it */
                ret = iwl_poll_bit(trans, CSR_HW_IF_CONFIG_REG,
                                CSR_HW_IF_CONFIG_REG_BIT_EEPROM_OWN_SEM,
                                CSR_HW_IF_CONFIG_REG_BIT_EEPROM_OWN_SEM,
                                EEPROM_SEM_TIMEOUT);
                if (ret >= 0) {
                        IWL_DEBUG_EEPROM(trans->dev,
                                         "Acquired semaphore after %d tries.\n",
                                         count+1);
                        return ret;
                }
        }

        return ret;
}

static void iwl_eeprom_release_semaphore(struct iwl_trans *trans)
{
        iwl_clear_bit(trans, CSR_HW_IF_CONFIG_REG,
                      CSR_HW_IF_CONFIG_REG_BIT_EEPROM_OWN_SEM);
}

static int iwl_eeprom_verify_signature(struct iwl_trans *trans, bool nvm_is_otp)
{
        u32 gp = iwl_read32(trans, CSR_EEPROM_GP) & CSR_EEPROM_GP_VALID_MSK;

        IWL_DEBUG_EEPROM(trans->dev, "EEPROM signature=0x%08x\n", gp);

        switch (gp) {
        case CSR_EEPROM_GP_BAD_SIG_EEP_GOOD_SIG_OTP:
                if (!nvm_is_otp) {
                        IWL_ERR(trans, "EEPROM with bad signature: 0x%08x\n",
                                gp);
                        return -ENOENT;
                }
                return 0;
        case CSR_EEPROM_GP_GOOD_SIG_EEP_LESS_THAN_4K:
        case CSR_EEPROM_GP_GOOD_SIG_EEP_MORE_THAN_4K:
                if (nvm_is_otp) {
                        IWL_ERR(trans, "OTP with bad signature: 0x%08x\n", gp);
                        return -ENOENT;
                }
                return 0;
        case CSR_EEPROM_GP_BAD_SIGNATURE_BOTH_EEP_AND_OTP:
        default:
                IWL_ERR(trans,
                        "bad EEPROM/OTP signature, type=%s, EEPROM_GP=0x%08x\n",
                        nvm_is_otp ? "OTP" : "EEPROM", gp);
                return -ENOENT;
        }
}

/******************************************************************************
 *
 * OTP related functions
 *
******************************************************************************/

static void iwl_set_otp_access_absolute(struct iwl_trans *trans)
{
        iwl_read32(trans, CSR_OTP_GP_REG);

        iwl_clear_bit(trans, CSR_OTP_GP_REG,
                      CSR_OTP_GP_REG_OTP_ACCESS_MODE);
}

static int iwl_nvm_is_otp(struct iwl_trans *trans)
{
        u32 otpgp;

        /* OTP only valid for CP/PP and after */
        switch (trans->hw_rev & CSR_HW_REV_TYPE_MSK) {
        case CSR_HW_REV_TYPE_NONE:
                IWL_ERR(trans, "Unknown hardware type\n");
                return -EIO;
        case CSR_HW_REV_TYPE_5300:
        case CSR_HW_REV_TYPE_5350:
        case CSR_HW_REV_TYPE_5100:
        case CSR_HW_REV_TYPE_5150:
                return 0;
        default:
                otpgp = iwl_read32(trans, CSR_OTP_GP_REG);
                if (otpgp & CSR_OTP_GP_REG_DEVICE_SELECT)
                        return 1;
                return 0;
        }
}

static int iwl_init_otp_access(struct iwl_trans *trans)
{
        int ret;

        ret = iwl_finish_nic_init(trans);
        if (ret)
                return ret;

        iwl_set_bits_prph(trans, APMG_PS_CTRL_REG,
                          APMG_PS_CTRL_VAL_RESET_REQ);
        udelay(5);
        iwl_clear_bits_prph(trans, APMG_PS_CTRL_REG,
                            APMG_PS_CTRL_VAL_RESET_REQ);

        /*
         * CSR auto clock gate disable bit -
         * this is only applicable for HW with OTP shadow RAM
         */
        if (trans->cfg->base_params->shadow_ram_support)
                iwl_set_bit(trans, CSR_DBG_LINK_PWR_MGMT_REG,
                            CSR_RESET_LINK_PWR_MGMT_DISABLED);

        return 0;
}

static int iwl_read_otp_word(struct iwl_trans *trans, u16 addr,
                             __le16 *eeprom_data)
{
        int ret = 0;
        u32 r;
        u32 otpgp;

        iwl_write32(trans, CSR_EEPROM_REG,
                    CSR_EEPROM_REG_MSK_ADDR & (addr << 1));
        ret = iwl_poll_bit(trans, CSR_EEPROM_REG,
                                 CSR_EEPROM_REG_READ_VALID_MSK,
                                 CSR_EEPROM_REG_READ_VALID_MSK,
                                 IWL_EEPROM_ACCESS_TIMEOUT);
        if (ret < 0) {
                IWL_ERR(trans, "Time out reading OTP[%d]\n", addr);
                return ret;
        }
        r = iwl_read32(trans, CSR_EEPROM_REG);
        /* check for ECC errors: */
        otpgp = iwl_read32(trans, CSR_OTP_GP_REG);
        if (otpgp & CSR_OTP_GP_REG_ECC_UNCORR_STATUS_MSK) {
                /* stop in this case */
                /* set the uncorrectable OTP ECC bit for acknowledgment */
                iwl_set_bit(trans, CSR_OTP_GP_REG,
                            CSR_OTP_GP_REG_ECC_UNCORR_STATUS_MSK);
                IWL_ERR(trans, "Uncorrectable OTP ECC error, abort OTP read\n");
                return -EINVAL;
        }
        if (otpgp & CSR_OTP_GP_REG_ECC_CORR_STATUS_MSK) {
                /* continue in this case */
                /* set the correctable OTP ECC bit for acknowledgment */
                iwl_set_bit(trans, CSR_OTP_GP_REG,
                            CSR_OTP_GP_REG_ECC_CORR_STATUS_MSK);
                IWL_ERR(trans, "Correctable OTP ECC error, continue read\n");
        }
        *eeprom_data = cpu_to_le16(r >> 16);
        return 0;
}

/*
 * iwl_is_otp_empty: check for empty OTP
 */
static bool iwl_is_otp_empty(struct iwl_trans *trans)
{
        u16 next_link_addr = 0;
        __le16 link_value;
        bool is_empty = false;

        /* locate the beginning of OTP link list */
        if (!iwl_read_otp_word(trans, next_link_addr, &link_value)) {
                if (!link_value) {
                        IWL_ERR(trans, "OTP is empty\n");
                        is_empty = true;
                }
        } else {
                IWL_ERR(trans, "Unable to read first block of OTP list.\n");
                is_empty = true;
        }

        return is_empty;
}


/*
 * iwl_find_otp_image: find EEPROM image in OTP
 *   finding the OTP block that contains the EEPROM image.
 *   the last valid block on the link list (the block _before_ the last block)
 *   is the block we should read and used to configure the device.
 *   If all the available OTP blocks are full, the last block will be the block
 *   we should read and used to configure the device.
 *   only perform this operation if shadow RAM is disabled
 */
static int iwl_find_otp_image(struct iwl_trans *trans,
                                        u16 *validblockaddr)
{
        u16 next_link_addr = 0, valid_addr;
        __le16 link_value = 0;
        int usedblocks = 0;

        /* set addressing mode to absolute to traverse the link list */
        iwl_set_otp_access_absolute(trans);

        /* checking for empty OTP or error */
        if (iwl_is_otp_empty(trans))
                return -EINVAL;

        /*
         * start traverse link list
         * until reach the max number of OTP blocks
         * different devices have different number of OTP blocks
         */
        do {
                /* save current valid block address
                 * check for more block on the link list
                 */
                valid_addr = next_link_addr;
                next_link_addr = le16_to_cpu(link_value) * sizeof(u16);
                IWL_DEBUG_EEPROM(trans->dev, "OTP blocks %d addr 0x%x\n",
                                 usedblocks, next_link_addr);
                if (iwl_read_otp_word(trans, next_link_addr, &link_value))
                        return -EINVAL;
                if (!link_value) {
                        /*
                         * reach the end of link list, return success and
                         * set address point to the starting address
                         * of the image
                         */
                        *validblockaddr = valid_addr;
                        /* skip first 2 bytes (link list pointer) */
                        *validblockaddr += 2;
                        return 0;
                }
                /* more in the link list, continue */
                usedblocks++;
        } while (usedblocks <= trans->cfg->base_params->max_ll_items);

        /* OTP has no valid blocks */
        IWL_DEBUG_EEPROM(trans->dev, "OTP has no valid blocks\n");
        return -EINVAL;
}

/**
 * iwl_read_eeprom - read EEPROM contents
 *
 * Load the EEPROM contents from adapter and return it
 * and its size.
 *
 * NOTE:  This routine uses the non-debug IO access functions.
 */
int iwl_read_eeprom(struct iwl_trans *trans, u8 **eeprom, size_t *eeprom_size)
{
        __le16 *e;
        u32 gp = iwl_read32(trans, CSR_EEPROM_GP);
        int sz;
        int ret;
        u16 addr;
        u16 validblockaddr = 0;
        u16 cache_addr = 0;
        int nvm_is_otp;

        if (!eeprom || !eeprom_size)
                return -EINVAL;

        nvm_is_otp = iwl_nvm_is_otp(trans);
        if (nvm_is_otp < 0)
                return nvm_is_otp;

        sz = trans->cfg->base_params->eeprom_size;
        IWL_DEBUG_EEPROM(trans->dev, "NVM size = %d\n", sz);

        e = kmalloc(sz, GFP_KERNEL);
        if (!e)
                return -ENOMEM;

        ret = iwl_eeprom_verify_signature(trans, nvm_is_otp);
        if (ret < 0) {
                IWL_ERR(trans, "EEPROM not found, EEPROM_GP=0x%08x\n", gp);
                goto err_free;
        }

        /* Make sure driver (instead of uCode) is allowed to read EEPROM */
        ret = iwl_eeprom_acquire_semaphore(trans);
        if (ret < 0) {
                IWL_ERR(trans, "Failed to acquire EEPROM semaphore.\n");
                goto err_free;
        }

        if (nvm_is_otp) {
                ret = iwl_init_otp_access(trans);
                if (ret) {
                        IWL_ERR(trans, "Failed to initialize OTP access.\n");
                        goto err_unlock;
                }

                iwl_write32(trans, CSR_EEPROM_GP,
                            iwl_read32(trans, CSR_EEPROM_GP) &
                            ~CSR_EEPROM_GP_IF_OWNER_MSK);

                iwl_set_bit(trans, CSR_OTP_GP_REG,
                            CSR_OTP_GP_REG_ECC_CORR_STATUS_MSK |
                            CSR_OTP_GP_REG_ECC_UNCORR_STATUS_MSK);
                /* traversing the linked list if no shadow ram supported */
                if (!trans->cfg->base_params->shadow_ram_support) {
                        ret = iwl_find_otp_image(trans, &validblockaddr);
                        if (ret)
                                goto err_unlock;
                }
                for (addr = validblockaddr; addr < validblockaddr + sz;
                     addr += sizeof(u16)) {
                        __le16 eeprom_data;

                        ret = iwl_read_otp_word(trans, addr, &eeprom_data);
                        if (ret)
                                goto err_unlock;
                        e[cache_addr / 2] = eeprom_data;
                        cache_addr += sizeof(u16);
                }
        } else {
                /* eeprom is an array of 16bit values */
                for (addr = 0; addr < sz; addr += sizeof(u16)) {
                        u32 r;

                        iwl_write32(trans, CSR_EEPROM_REG,
                                    CSR_EEPROM_REG_MSK_ADDR & (addr << 1));

                        ret = iwl_poll_bit(trans, CSR_EEPROM_REG,
                                           CSR_EEPROM_REG_READ_VALID_MSK,
                                           CSR_EEPROM_REG_READ_VALID_MSK,
                                           IWL_EEPROM_ACCESS_TIMEOUT);
                        if (ret < 0) {
                                IWL_ERR(trans,
                                        "Time out reading EEPROM[%d]\n", addr);
                                goto err_unlock;
                        }
                        r = iwl_read32(trans, CSR_EEPROM_REG);
                        e[addr / 2] = cpu_to_le16(r >> 16);
                }
        }

        IWL_DEBUG_EEPROM(trans->dev, "NVM Type: %s\n",
                         nvm_is_otp ? "OTP" : "EEPROM");

        iwl_eeprom_release_semaphore(trans);

        *eeprom_size = sz;
        *eeprom = (u8 *)e;
        return 0;

 err_unlock:
        iwl_eeprom_release_semaphore(trans);
 err_free:
        kfree(e);

        return ret;
}
IWL_EXPORT_SYMBOL(iwl_read_eeprom);