iwl-eeprom-read.c

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/******************************************************************************
 *
 * 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 - 2012 Intel Corporation. All rights reserved.
 *
 * 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.
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110,
 * USA
 *
 * The full GNU General Public License is included in this distribution
 * in the file called LICENSE.GPL.
 *
 * Contact Information:
 *  Intel Linux Wireless <[email protected]>
 * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
 *
 * BSD LICENSE
 *
 * Copyright(c) 2005 - 2012 Intel Corporation. All rights reserved.
 * 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-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;

    /* Enable 40MHz radio clock */
    iwl_write32(trans, CSR_GP_CNTRL,
            iwl_read32(trans, CSR_GP_CNTRL) |
            CSR_GP_CNTRL_REG_FLAG_INIT_DONE);

    /* wait for clock to be ready */
    ret = iwl_poll_bit(trans, CSR_GP_CNTRL,
               CSR_GP_CNTRL_REG_FLAG_MAC_CLOCK_READY,
               CSR_GP_CNTRL_REG_FLAG_MAC_CLOCK_READY,
               25000);
    if (ret < 0) {
        IWL_ERR(trans, "Time out access OTP\n");
    } else {
        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 ret;
}

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 acknowledgement */
        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 acknowledgement */
        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;
}

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;
}
EXPORT_SYMBOL_GPL(iwl_read_eeprom);