if_spi.c

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/*
 *  linux/drivers/net/wireless/libertas/if_spi.c
 *
 *  Driver for Marvell SPI WLAN cards.
 *
 *  Copyright 2008 Analog Devices Inc.
 *
 *  Authors:
 *  Andrey Yurovsky <[email protected]>
 *  Colin McCabe <[email protected]>
 *
 *  Inspired by if_sdio.c, Copyright 2007-2008 Pierre Ossman
 *
 * 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.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/hardirq.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/firmware.h>
#include <linux/jiffies.h>
#include <linux/list.h>
#include <linux/netdevice.h>
#include <linux/slab.h>
#include <linux/spi/libertas_spi.h>
#include <linux/spi/spi.h>

#include "host.h"
#include "decl.h"
#include "defs.h"
#include "dev.h"
#include "if_spi.h"

struct if_spi_packet {
    struct list_head        list;
    u16             blen;
    u8              buffer[0] __attribute__((aligned(4)));
};

struct if_spi_card {
    struct spi_device       *spi;
    struct lbs_private      *priv;
    struct libertas_spi_platform_data *pdata;

    /* The card ID and card revision, as reported by the hardware. */
    u16             card_id;
    u8              card_rev;

    /* The last time that we initiated an SPU operation */
    unsigned long           prev_xfer_time;

    int             use_dummy_writes;
    unsigned long           spu_port_delay;
    unsigned long           spu_reg_delay;

    /* Handles all SPI communication (except for FW load) */
    struct workqueue_struct     *workqueue;
    struct work_struct      packet_work;
    struct work_struct      resume_work;

    u8              cmd_buffer[IF_SPI_CMD_BUF_SIZE];

    /* A buffer of incoming packets from libertas core.
     * Since we can't sleep in hw_host_to_card, we have to buffer
     * them. */
    struct list_head        cmd_packet_list;
    struct list_head        data_packet_list;

    /* Protects cmd_packet_list and data_packet_list */
    spinlock_t          buffer_lock;

    /* True is card suspended */
    u8              suspended;
};

static void free_if_spi_card(struct if_spi_card *card)
{
    struct list_head *cursor, *next;
    struct if_spi_packet *packet;

    list_for_each_safe(cursor, next, &card->cmd_packet_list) {
        packet = container_of(cursor, struct if_spi_packet, list);
        list_del(&packet->list);
        kfree(packet);
    }
    list_for_each_safe(cursor, next, &card->data_packet_list) {
        packet = container_of(cursor, struct if_spi_packet, list);
        list_del(&packet->list);
        kfree(packet);
    }
    spi_set_drvdata(card->spi, NULL);
    kfree(card);
}

#define MODEL_8385  0x04
#define MODEL_8686  0x0b
#define MODEL_8688  0x10

static const struct lbs_fw_table fw_table[] = {
    { MODEL_8385, "libertas/gspi8385_helper.bin", "libertas/gspi8385.bin" },
    { MODEL_8385, "libertas/gspi8385_hlp.bin", "libertas/gspi8385.bin" },
    { MODEL_8686, "libertas/gspi8686_v9_helper.bin", "libertas/gspi8686_v9.bin" },
    { MODEL_8686, "libertas/gspi8686_hlp.bin", "libertas/gspi8686.bin" },
    { MODEL_8688, "libertas/gspi8688_helper.bin", "libertas/gspi8688.bin" },
    { 0, NULL, NULL }
};
MODULE_FIRMWARE("libertas/gspi8385_helper.bin");
MODULE_FIRMWARE("libertas/gspi8385_hlp.bin");
MODULE_FIRMWARE("libertas/gspi8385.bin");
MODULE_FIRMWARE("libertas/gspi8686_v9_helper.bin");
MODULE_FIRMWARE("libertas/gspi8686_v9.bin");
MODULE_FIRMWARE("libertas/gspi8686_hlp.bin");
MODULE_FIRMWARE("libertas/gspi8686.bin");
MODULE_FIRMWARE("libertas/gspi8688_helper.bin");
MODULE_FIRMWARE("libertas/gspi8688.bin");


/*
 * SPI Interface Unit Routines
 *
 * The SPU sits between the host and the WLAN module.
 * All communication with the firmware is through SPU transactions.
 *
 * First we have to put a SPU register name on the bus. Then we can
 * either read from or write to that register.
 *
 */

static void spu_transaction_init(struct if_spi_card *card)
{
    if (!time_after(jiffies, card->prev_xfer_time + 1)) {
        /* Unfortunately, the SPU requires a delay between successive
         * transactions. If our last transaction was more than a jiffy
         * ago, we have obviously already delayed enough.
         * If not, we have to busy-wait to be on the safe side. */
        ndelay(400);
    }
}

static void spu_transaction_finish(struct if_spi_card *card)
{
    card->prev_xfer_time = jiffies;
}

/*
 * Write out a byte buffer to an SPI register,
 * using a series of 16-bit transfers.
 */
static int spu_write(struct if_spi_card *card, u16 reg, const u8 *buf, int len)
{
    int err = 0;
    __le16 reg_out = cpu_to_le16(reg | IF_SPI_WRITE_OPERATION_MASK);
    struct spi_message m;
    struct spi_transfer reg_trans;
    struct spi_transfer data_trans;

    spi_message_init(&m);
    memset(&reg_trans, 0, sizeof(reg_trans));
    memset(&data_trans, 0, sizeof(data_trans));

    /* You must give an even number of bytes to the SPU, even if it
     * doesn't care about the last one.  */
    BUG_ON(len & 0x1);

    spu_transaction_init(card);

    /* write SPU register index */
    reg_trans.tx_buf = &reg_out;
    reg_trans.len = sizeof(reg_out);

    data_trans.tx_buf = buf;
    data_trans.len = len;

    spi_message_add_tail(&reg_trans, &m);
    spi_message_add_tail(&data_trans, &m);

    err = spi_sync(card->spi, &m);
    spu_transaction_finish(card);
    return err;
}

static inline int spu_write_u16(struct if_spi_card *card, u16 reg, u16 val)
{
    __le16 buff;

    buff = cpu_to_le16(val);
    return spu_write(card, reg, (u8 *)&buff, sizeof(u16));
}

static inline int spu_reg_is_port_reg(u16 reg)
{
    switch (reg) {
    case IF_SPI_IO_RDWRPORT_REG:
    case IF_SPI_CMD_RDWRPORT_REG:
    case IF_SPI_DATA_RDWRPORT_REG:
        return 1;
    default:
        return 0;
    }
}

static int spu_read(struct if_spi_card *card, u16 reg, u8 *buf, int len)
{
    unsigned int delay;
    int err = 0;
    __le16 reg_out = cpu_to_le16(reg | IF_SPI_READ_OPERATION_MASK);
    struct spi_message m;
    struct spi_transfer reg_trans;
    struct spi_transfer dummy_trans;
    struct spi_transfer data_trans;

    /*
     * You must take an even number of bytes from the SPU, even if you
     * don't care about the last one.
     */
    BUG_ON(len & 0x1);

    spu_transaction_init(card);

    spi_message_init(&m);
    memset(&reg_trans, 0, sizeof(reg_trans));
    memset(&dummy_trans, 0, sizeof(dummy_trans));
    memset(&data_trans, 0, sizeof(data_trans));

    /* write SPU register index */
    reg_trans.tx_buf = &reg_out;
    reg_trans.len = sizeof(reg_out);
    spi_message_add_tail(&reg_trans, &m);

    delay = spu_reg_is_port_reg(reg) ? card->spu_port_delay :
                        card->spu_reg_delay;
    if (card->use_dummy_writes) {
        /* Clock in dummy cycles while the SPU fills the FIFO */
        dummy_trans.len = delay / 8;
        spi_message_add_tail(&dummy_trans, &m);
    } else {
        /* Busy-wait while the SPU fills the FIFO */
        reg_trans.delay_usecs =
            DIV_ROUND_UP((100 + (delay * 10)), 1000);
    }

    /* read in data */
    data_trans.rx_buf = buf;
    data_trans.len = len;
    spi_message_add_tail(&data_trans, &m);

    err = spi_sync(card->spi, &m);
    spu_transaction_finish(card);
    return err;
}

/* Read 16 bits from an SPI register */
static inline int spu_read_u16(struct if_spi_card *card, u16 reg, u16 *val)
{
    __le16 buf;
    int ret;

    ret = spu_read(card, reg, (u8 *)&buf, sizeof(buf));
    if (ret == 0)
        *val = le16_to_cpup(&buf);
    return ret;
}

/*
 * Read 32 bits from an SPI register.
 * The low 16 bits are read first.
 */
static int spu_read_u32(struct if_spi_card *card, u16 reg, u32 *val)
{
    __le32 buf;
    int err;

    err = spu_read(card, reg, (u8 *)&buf, sizeof(buf));
    if (!err)
        *val = le32_to_cpup(&buf);
    return err;
}

/*
 * Keep reading 16 bits from an SPI register until you get the correct result.
 *
 * If mask = 0, the correct result is any non-zero number.
 * If mask != 0, the correct result is any number where
 * number & target_mask == target
 *
 * Returns -ETIMEDOUT if a second passes without the correct result.
 */
static int spu_wait_for_u16(struct if_spi_card *card, u16 reg,
            u16 target_mask, u16 target)
{
    int err;
    unsigned long timeout = jiffies + 5*HZ;
    while (1) {
        u16 val;
        err = spu_read_u16(card, reg, &val);
        if (err)
            return err;
        if (target_mask) {
            if ((val & target_mask) == target)
                return 0;
        } else {
            if (val)
                return 0;
        }
        udelay(100);
        if (time_after(jiffies, timeout)) {
            pr_err("%s: timeout with val=%02x, target_mask=%02x, target=%02x\n",
                   __func__, val, target_mask, target);
            return -ETIMEDOUT;
        }
    }
}

/*
 * Read 16 bits from an SPI register until you receive a specific value.
 * Returns -ETIMEDOUT if a 4 tries pass without success.
 */
static int spu_wait_for_u32(struct if_spi_card *card, u32 reg, u32 target)
{
    int err, try;
    for (try = 0; try < 4; ++try) {
        u32 val = 0;
        err = spu_read_u32(card, reg, &val);
        if (err)
            return err;
        if (val == target)
            return 0;
        mdelay(100);
    }
    return -ETIMEDOUT;
}

static int spu_set_interrupt_mode(struct if_spi_card *card,
               int suppress_host_int,
               int auto_int)
{
    int err = 0;

    /*
     * We can suppress a host interrupt by clearing the appropriate
     * bit in the "host interrupt status mask" register
     */
    if (suppress_host_int) {
        err = spu_write_u16(card, IF_SPI_HOST_INT_STATUS_MASK_REG, 0);
        if (err)
            return err;
    } else {
        err = spu_write_u16(card, IF_SPI_HOST_INT_STATUS_MASK_REG,
                  IF_SPI_HISM_TX_DOWNLOAD_RDY |
                  IF_SPI_HISM_RX_UPLOAD_RDY |
                  IF_SPI_HISM_CMD_DOWNLOAD_RDY |
                  IF_SPI_HISM_CARDEVENT |
                  IF_SPI_HISM_CMD_UPLOAD_RDY);
        if (err)
            return err;
    }

    /*
     * If auto-interrupts are on, the completion of certain transactions
     * will trigger an interrupt automatically. If auto-interrupts
     * are off, we need to set the "Card Interrupt Cause" register to
     * trigger a card interrupt.
     */
    if (auto_int) {
        err = spu_write_u16(card, IF_SPI_HOST_INT_CTRL_REG,
                IF_SPI_HICT_TX_DOWNLOAD_OVER_AUTO |
                IF_SPI_HICT_RX_UPLOAD_OVER_AUTO |
                IF_SPI_HICT_CMD_DOWNLOAD_OVER_AUTO |
                IF_SPI_HICT_CMD_UPLOAD_OVER_AUTO);
        if (err)
            return err;
    } else {
        err = spu_write_u16(card, IF_SPI_HOST_INT_STATUS_MASK_REG, 0);
        if (err)
            return err;
    }
    return err;
}

static int spu_get_chip_revision(struct if_spi_card *card,
                  u16 *card_id, u8 *card_rev)
{
    int err = 0;
    u32 dev_ctrl;
    err = spu_read_u32(card, IF_SPI_DEVICEID_CTRL_REG, &dev_ctrl);
    if (err)
        return err;
    *card_id = IF_SPI_DEVICEID_CTRL_REG_TO_CARD_ID(dev_ctrl);
    *card_rev = IF_SPI_DEVICEID_CTRL_REG_TO_CARD_REV(dev_ctrl);
    return err;
}

static int spu_set_bus_mode(struct if_spi_card *card, u16 mode)
{
    int err = 0;
    u16 rval;
    /* set bus mode */
    err = spu_write_u16(card, IF_SPI_SPU_BUS_MODE_REG, mode);
    if (err)
        return err;
    /* Check that we were able to read back what we just wrote. */
    err = spu_read_u16(card, IF_SPI_SPU_BUS_MODE_REG, &rval);
    if (err)
        return err;
    if ((rval & 0xF) != mode) {
        pr_err("Can't read bus mode register\n");
        return -EIO;
    }
    return 0;
}

static int spu_init(struct if_spi_card *card, int use_dummy_writes)
{
    int err = 0;
    u32 delay;

    /*
     * We have to start up in timed delay mode so that we can safely
     * read the Delay Read Register.
     */
    card->use_dummy_writes = 0;
    err = spu_set_bus_mode(card,
                IF_SPI_BUS_MODE_SPI_CLOCK_PHASE_RISING |
                IF_SPI_BUS_MODE_DELAY_METHOD_TIMED |
                IF_SPI_BUS_MODE_16_BIT_ADDRESS_16_BIT_DATA);
    if (err)
        return err;
    card->spu_port_delay = 1000;
    card->spu_reg_delay = 1000;
    err = spu_read_u32(card, IF_SPI_DELAY_READ_REG, &delay);
    if (err)
        return err;
    card->spu_port_delay = delay & 0x0000ffff;
    card->spu_reg_delay = (delay & 0xffff0000) >> 16;

    /* If dummy clock delay mode has been requested, switch to it now */
    if (use_dummy_writes) {
        card->use_dummy_writes = 1;
        err = spu_set_bus_mode(card,
                IF_SPI_BUS_MODE_SPI_CLOCK_PHASE_RISING |
                IF_SPI_BUS_MODE_DELAY_METHOD_DUMMY_CLOCK |
                IF_SPI_BUS_MODE_16_BIT_ADDRESS_16_BIT_DATA);
        if (err)
            return err;
    }

    lbs_deb_spi("Initialized SPU unit. "
            "spu_port_delay=0x%04lx, spu_reg_delay=0x%04lx\n",
            card->spu_port_delay, card->spu_reg_delay);
    return err;
}

/*
 * Firmware Loading
 */

static int if_spi_prog_helper_firmware(struct if_spi_card *card,
                    const struct firmware *firmware)
{
    int err = 0;
    int bytes_remaining;
    const u8 *fw;
    u8 temp[HELPER_FW_LOAD_CHUNK_SZ];

    lbs_deb_enter(LBS_DEB_SPI);

    err = spu_set_interrupt_mode(card, 1, 0);
    if (err)
        goto out;

    bytes_remaining = firmware->size;
    fw = firmware->data;

    /* Load helper firmware image */
    while (bytes_remaining > 0) {
        /*
         * Scratch pad 1 should contain the number of bytes we
         * want to download to the firmware
         */
        err = spu_write_u16(card, IF_SPI_SCRATCH_1_REG,
                    HELPER_FW_LOAD_CHUNK_SZ);
        if (err)
            goto out;

        err = spu_wait_for_u16(card, IF_SPI_HOST_INT_STATUS_REG,
                    IF_SPI_HIST_CMD_DOWNLOAD_RDY,
                    IF_SPI_HIST_CMD_DOWNLOAD_RDY);
        if (err)
            goto out;

        /*
         * Feed the data into the command read/write port reg
         * in chunks of 64 bytes
         */
        memset(temp, 0, sizeof(temp));
        memcpy(temp, fw,
               min(bytes_remaining, HELPER_FW_LOAD_CHUNK_SZ));
        mdelay(10);
        err = spu_write(card, IF_SPI_CMD_RDWRPORT_REG,
                    temp, HELPER_FW_LOAD_CHUNK_SZ);
        if (err)
            goto out;

        /* Interrupt the boot code */
        err = spu_write_u16(card, IF_SPI_HOST_INT_STATUS_REG, 0);
        if (err)
            goto out;
        err = spu_write_u16(card, IF_SPI_CARD_INT_CAUSE_REG,
                       IF_SPI_CIC_CMD_DOWNLOAD_OVER);
        if (err)
            goto out;
        bytes_remaining -= HELPER_FW_LOAD_CHUNK_SZ;
        fw += HELPER_FW_LOAD_CHUNK_SZ;
    }

    /*
     * Once the helper / single stage firmware download is complete,
     * write 0 to scratch pad 1 and interrupt the
     * bootloader. This completes the helper download.
     */
    err = spu_write_u16(card, IF_SPI_SCRATCH_1_REG, FIRMWARE_DNLD_OK);
    if (err)
        goto out;
    err = spu_write_u16(card, IF_SPI_HOST_INT_STATUS_REG, 0);
    if (err)
        goto out;
    err = spu_write_u16(card, IF_SPI_CARD_INT_CAUSE_REG,
                IF_SPI_CIC_CMD_DOWNLOAD_OVER);
out:
    if (err)
        pr_err("failed to load helper firmware (err=%d)\n", err);
    lbs_deb_leave_args(LBS_DEB_SPI, "err %d", err);
    return err;
}

/*
 * Returns the length of the next packet the firmware expects us to send.
 * Sets crc_err if the previous transfer had a CRC error.
 */
static int if_spi_prog_main_firmware_check_len(struct if_spi_card *card,
                        int *crc_err)
{
    u16 len;
    int err = 0;

    /*
     * wait until the host interrupt status register indicates
     * that we are ready to download
     */
    err = spu_wait_for_u16(card, IF_SPI_HOST_INT_STATUS_REG,
                IF_SPI_HIST_CMD_DOWNLOAD_RDY,
                IF_SPI_HIST_CMD_DOWNLOAD_RDY);
    if (err) {
        pr_err("timed out waiting for host_int_status\n");
        return err;
    }

    /* Ask the device how many bytes of firmware it wants. */
    err = spu_read_u16(card, IF_SPI_SCRATCH_1_REG, &len);
    if (err)
        return err;

    if (len > IF_SPI_CMD_BUF_SIZE) {
        pr_err("firmware load device requested a larger transfer than we are prepared to handle (len = %d)\n",
               len);
        return -EIO;
    }
    if (len & 0x1) {
        lbs_deb_spi("%s: crc error\n", __func__);
        len &= ~0x1;
        *crc_err = 1;
    } else
        *crc_err = 0;

    return len;
}

static int if_spi_prog_main_firmware(struct if_spi_card *card,
                    const struct firmware *firmware)
{
    struct lbs_private *priv = card->priv;
    int len, prev_len;
    int bytes, crc_err = 0, err = 0;
    const u8 *fw;
    u16 num_crc_errs;

    lbs_deb_enter(LBS_DEB_SPI);

    err = spu_set_interrupt_mode(card, 1, 0);
    if (err)
        goto out;

    err = spu_wait_for_u16(card, IF_SPI_SCRATCH_1_REG, 0, 0);
    if (err) {
        netdev_err(priv->dev,
               "%s: timed out waiting for initial scratch reg = 0\n",
               __func__);
        goto out;
    }

    num_crc_errs = 0;
    prev_len = 0;
    bytes = firmware->size;
    fw = firmware->data;
    while ((len = if_spi_prog_main_firmware_check_len(card, &crc_err))) {
        if (len < 0) {
            err = len;
            goto out;
        }
        if (bytes < 0) {
            /*
             * If there are no more bytes left, we would normally
             * expect to have terminated with len = 0
             */
            netdev_err(priv->dev,
                   "Firmware load wants more bytes than we have to offer.\n");
            break;
        }
        if (crc_err) {
            /* Previous transfer failed. */
            if (++num_crc_errs > MAX_MAIN_FW_LOAD_CRC_ERR) {
                pr_err("Too many CRC errors encountered in firmware load.\n");
                err = -EIO;
                goto out;
            }
        } else {
            /* Previous transfer succeeded. Advance counters. */
            bytes -= prev_len;
            fw += prev_len;
        }
        if (bytes < len) {
            memset(card->cmd_buffer, 0, len);
            memcpy(card->cmd_buffer, fw, bytes);
        } else
            memcpy(card->cmd_buffer, fw, len);

        err = spu_write_u16(card, IF_SPI_HOST_INT_STATUS_REG, 0);
        if (err)
            goto out;
        err = spu_write(card, IF_SPI_CMD_RDWRPORT_REG,
                card->cmd_buffer, len);
        if (err)
            goto out;
        err = spu_write_u16(card, IF_SPI_CARD_INT_CAUSE_REG ,
                    IF_SPI_CIC_CMD_DOWNLOAD_OVER);
        if (err)
            goto out;
        prev_len = len;
    }
    if (bytes > prev_len) {
        pr_err("firmware load wants fewer bytes than we have to offer\n");
    }

    /* Confirm firmware download */
    err = spu_wait_for_u32(card, IF_SPI_SCRATCH_4_REG,
                    SUCCESSFUL_FW_DOWNLOAD_MAGIC);
    if (err) {
        pr_err("failed to confirm the firmware download\n");
        goto out;
    }

out:
    if (err)
        pr_err("failed to load firmware (err=%d)\n", err);
    lbs_deb_leave_args(LBS_DEB_SPI, "err %d", err);
    return err;
}

/*
 * SPI Transfer Thread
 *
 * The SPI worker handles all SPI transfers, so there is no need for a lock.
 */

/* Move a command from the card to the host */
static int if_spi_c2h_cmd(struct if_spi_card *card)
{
    struct lbs_private *priv = card->priv;
    unsigned long flags;
    int err = 0;
    u16 len;
    u8 i;

    /*
     * We need a buffer big enough to handle whatever people send to
     * hw_host_to_card
     */
    BUILD_BUG_ON(IF_SPI_CMD_BUF_SIZE < LBS_CMD_BUFFER_SIZE);
    BUILD_BUG_ON(IF_SPI_CMD_BUF_SIZE < LBS_UPLD_SIZE);

    /*
     * It's just annoying if the buffer size isn't a multiple of 4, because
     * then we might have len < IF_SPI_CMD_BUF_SIZE but
     * ALIGN(len, 4) > IF_SPI_CMD_BUF_SIZE
     */
    BUILD_BUG_ON(IF_SPI_CMD_BUF_SIZE % 4 != 0);

    lbs_deb_enter(LBS_DEB_SPI);

    /* How many bytes are there to read? */
    err = spu_read_u16(card, IF_SPI_SCRATCH_2_REG, &len);
    if (err)
        goto out;
    if (!len) {
        netdev_err(priv->dev, "%s: error: card has no data for host\n",
               __func__);
        err = -EINVAL;
        goto out;
    } else if (len > IF_SPI_CMD_BUF_SIZE) {
        netdev_err(priv->dev,
               "%s: error: response packet too large: %d bytes, but maximum is %d\n",
               __func__, len, IF_SPI_CMD_BUF_SIZE);
        err = -EINVAL;
        goto out;
    }

    /* Read the data from the WLAN module into our command buffer */
    err = spu_read(card, IF_SPI_CMD_RDWRPORT_REG,
                card->cmd_buffer, ALIGN(len, 4));
    if (err)
        goto out;

    spin_lock_irqsave(&priv->driver_lock, flags);
    i = (priv->resp_idx == 0) ? 1 : 0;
    BUG_ON(priv->resp_len[i]);
    priv->resp_len[i] = len;
    memcpy(priv->resp_buf[i], card->cmd_buffer, len);
    lbs_notify_command_response(priv, i);
    spin_unlock_irqrestore(&priv->driver_lock, flags);

out:
    if (err)
        netdev_err(priv->dev, "%s: err=%d\n", __func__, err);
    lbs_deb_leave(LBS_DEB_SPI);
    return err;
}

/* Move data from the card to the host */
static int if_spi_c2h_data(struct if_spi_card *card)
{
    struct lbs_private *priv = card->priv;
    struct sk_buff *skb;
    char *data;
    u16 len;
    int err = 0;

    lbs_deb_enter(LBS_DEB_SPI);

    /* How many bytes are there to read? */
    err = spu_read_u16(card, IF_SPI_SCRATCH_1_REG, &len);
    if (err)
        goto out;
    if (!len) {
        netdev_err(priv->dev, "%s: error: card has no data for host\n",
               __func__);
        err = -EINVAL;
        goto out;
    } else if (len > MRVDRV_ETH_RX_PACKET_BUFFER_SIZE) {
        netdev_err(priv->dev,
               "%s: error: card has %d bytes of data, but our maximum skb size is %zu\n",
               __func__, len, MRVDRV_ETH_RX_PACKET_BUFFER_SIZE);
        err = -EINVAL;
        goto out;
    }

    /* TODO: should we allocate a smaller skb if we have less data? */
    skb = dev_alloc_skb(MRVDRV_ETH_RX_PACKET_BUFFER_SIZE);
    if (!skb) {
        err = -ENOBUFS;
        goto out;
    }
    skb_reserve(skb, IPFIELD_ALIGN_OFFSET);
    data = skb_put(skb, len);

    /* Read the data from the WLAN module into our skb... */
    err = spu_read(card, IF_SPI_DATA_RDWRPORT_REG, data, ALIGN(len, 4));
    if (err)
        goto free_skb;

    /* pass the SKB to libertas */
    err = lbs_process_rxed_packet(card->priv, skb);
    if (err)
        goto free_skb;

    /* success */
    goto out;

free_skb:
    dev_kfree_skb(skb);
out:
    if (err)
        netdev_err(priv->dev, "%s: err=%d\n", __func__, err);
    lbs_deb_leave(LBS_DEB_SPI);
    return err;
}

/* Move data or a command from the host to the card. */
static void if_spi_h2c(struct if_spi_card *card,
            struct if_spi_packet *packet, int type)
{
    struct lbs_private *priv = card->priv;
    int err = 0;
    u16 int_type, port_reg;

    switch (type) {
    case MVMS_DAT:
        int_type = IF_SPI_CIC_TX_DOWNLOAD_OVER;
        port_reg = IF_SPI_DATA_RDWRPORT_REG;
        break;
    case MVMS_CMD:
        int_type = IF_SPI_CIC_CMD_DOWNLOAD_OVER;
        port_reg = IF_SPI_CMD_RDWRPORT_REG;
        break;
    default:
        netdev_err(priv->dev, "can't transfer buffer of type %d\n",
               type);
        err = -EINVAL;
        goto out;
    }

    /* Write the data to the card */
    err = spu_write(card, port_reg, packet->buffer, packet->blen);
    if (err)
        goto out;

out:
    kfree(packet);

    if (err)
        netdev_err(priv->dev, "%s: error %d\n", __func__, err);
}

/* Inform the host about a card event */
static void if_spi_e2h(struct if_spi_card *card)
{
    int err = 0;
    u32 cause;
    struct lbs_private *priv = card->priv;

    err = spu_read_u32(card, IF_SPI_SCRATCH_3_REG, &cause);
    if (err)
        goto out;

    /* re-enable the card event interrupt */
    spu_write_u16(card, IF_SPI_HOST_INT_STATUS_REG,
            ~IF_SPI_HICU_CARD_EVENT);

    /* generate a card interrupt */
    spu_write_u16(card, IF_SPI_CARD_INT_CAUSE_REG, IF_SPI_CIC_HOST_EVENT);

    lbs_queue_event(priv, cause & 0xff);
out:
    if (err)
        netdev_err(priv->dev, "%s: error %d\n", __func__, err);
}

static void if_spi_host_to_card_worker(struct work_struct *work)
{
    int err;
    struct if_spi_card *card;
    u16 hiStatus;
    unsigned long flags;
    struct if_spi_packet *packet;
    struct lbs_private *priv;

    card = container_of(work, struct if_spi_card, packet_work);
    priv = card->priv;

    lbs_deb_enter(LBS_DEB_SPI);

    /*
     * Read the host interrupt status register to see what we
     * can do.
     */
    err = spu_read_u16(card, IF_SPI_HOST_INT_STATUS_REG,
                &hiStatus);
    if (err) {
        netdev_err(priv->dev, "I/O error\n");
        goto err;
    }

    if (hiStatus & IF_SPI_HIST_CMD_UPLOAD_RDY) {
        err = if_spi_c2h_cmd(card);
        if (err)
            goto err;
    }
    if (hiStatus & IF_SPI_HIST_RX_UPLOAD_RDY) {
        err = if_spi_c2h_data(card);
        if (err)
            goto err;
    }

    /*
     * workaround: in PS mode, the card does not set the Command
     * Download Ready bit, but it sets TX Download Ready.
     */
    if (hiStatus & IF_SPI_HIST_CMD_DOWNLOAD_RDY ||
       (card->priv->psstate != PS_STATE_FULL_POWER &&
        (hiStatus & IF_SPI_HIST_TX_DOWNLOAD_RDY))) {
        /*
         * This means two things. First of all,
         * if there was a previous command sent, the card has
         * successfully received it.
         * Secondly, it is now ready to download another
         * command.
         */
        lbs_host_to_card_done(card->priv);

        /* Do we have any command packets from the host to send? */
        packet = NULL;
        spin_lock_irqsave(&card->buffer_lock, flags);
        if (!list_empty(&card->cmd_packet_list)) {
            packet = (struct if_spi_packet *)(card->
                    cmd_packet_list.next);
            list_del(&packet->list);
        }
        spin_unlock_irqrestore(&card->buffer_lock, flags);

        if (packet)
            if_spi_h2c(card, packet, MVMS_CMD);
    }
    if (hiStatus & IF_SPI_HIST_TX_DOWNLOAD_RDY) {
        /* Do we have any data packets from the host to send? */
        packet = NULL;
        spin_lock_irqsave(&card->buffer_lock, flags);
        if (!list_empty(&card->data_packet_list)) {
            packet = (struct if_spi_packet *)(card->
                    data_packet_list.next);
            list_del(&packet->list);
        }
        spin_unlock_irqrestore(&card->buffer_lock, flags);

        if (packet)
            if_spi_h2c(card, packet, MVMS_DAT);
    }
    if (hiStatus & IF_SPI_HIST_CARD_EVENT)
        if_spi_e2h(card);

err:
    if (err)
        netdev_err(priv->dev, "%s: got error %d\n", __func__, err);

    lbs_deb_leave(LBS_DEB_SPI);
}

/*
 * Host to Card
 *
 * Called from Libertas to transfer some data to the WLAN device
 * We can't sleep here.
 */
static int if_spi_host_to_card(struct lbs_private *priv,
                u8 type, u8 *buf, u16 nb)
{
    int err = 0;
    unsigned long flags;
    struct if_spi_card *card = priv->card;
    struct if_spi_packet *packet;
    u16 blen;

    lbs_deb_enter_args(LBS_DEB_SPI, "type %d, bytes %d", type, nb);

    if (nb == 0) {
        netdev_err(priv->dev, "%s: invalid size requested: %d\n",
               __func__, nb);
        err = -EINVAL;
        goto out;
    }
    blen = ALIGN(nb, 4);
    packet = kzalloc(sizeof(struct if_spi_packet) + blen, GFP_ATOMIC);
    if (!packet) {
        err = -ENOMEM;
        goto out;
    }
    packet->blen = blen;
    memcpy(packet->buffer, buf, nb);
    memset(packet->buffer + nb, 0, blen - nb);

    switch (type) {
    case MVMS_CMD:
        priv->dnld_sent = DNLD_CMD_SENT;
        spin_lock_irqsave(&card->buffer_lock, flags);
        list_add_tail(&packet->list, &card->cmd_packet_list);
        spin_unlock_irqrestore(&card->buffer_lock, flags);
        break;
    case MVMS_DAT:
        priv->dnld_sent = DNLD_DATA_SENT;
        spin_lock_irqsave(&card->buffer_lock, flags);
        list_add_tail(&packet->list, &card->data_packet_list);
        spin_unlock_irqrestore(&card->buffer_lock, flags);
        break;
    default:
        kfree(packet);
        netdev_err(priv->dev, "can't transfer buffer of type %d\n",
               type);
        err = -EINVAL;
        break;
    }

    /* Queue spi xfer work */
    queue_work(card->workqueue, &card->packet_work);
out:
    lbs_deb_leave_args(LBS_DEB_SPI, "err=%d", err);
    return err;
}

/*
 * Host Interrupts
 *
 * Service incoming interrupts from the WLAN device. We can't sleep here, so
 * don't try to talk on the SPI bus, just queue the SPI xfer work.
 */
static irqreturn_t if_spi_host_interrupt(int irq, void *dev_id)
{
    struct if_spi_card *card = dev_id;

    queue_work(card->workqueue, &card->packet_work);

    return IRQ_HANDLED;
}

/*
 * SPI callbacks
 */

static int if_spi_init_card(struct if_spi_card *card)
{
    struct lbs_private *priv = card->priv;
    int err, i;
    u32 scratch;
    const struct firmware *helper = NULL;
    const struct firmware *mainfw = NULL;

    lbs_deb_enter(LBS_DEB_SPI);

    err = spu_init(card, card->pdata->use_dummy_writes);
    if (err)
        goto out;
    err = spu_get_chip_revision(card, &card->card_id, &card->card_rev);
    if (err)
        goto out;

    err = spu_read_u32(card, IF_SPI_SCRATCH_4_REG, &scratch);
    if (err)
        goto out;
    if (scratch == SUCCESSFUL_FW_DOWNLOAD_MAGIC)
        lbs_deb_spi("Firmware is already loaded for "
                "Marvell WLAN 802.11 adapter\n");
    else {
        /* Check if we support this card */
        for (i = 0; i < ARRAY_SIZE(fw_table); i++) {
            if (card->card_id == fw_table[i].model)
                break;
        }
        if (i == ARRAY_SIZE(fw_table)) {
            netdev_err(priv->dev, "Unsupported chip_id: 0x%02x\n",
                   card->card_id);
            err = -ENODEV;
            goto out;
        }

        err = lbs_get_firmware(&card->spi->dev, card->card_id,
                    &fw_table[0], &helper, &mainfw);
        if (err) {
            netdev_err(priv->dev, "failed to find firmware (%d)\n",
                   err);
            goto out;
        }

        lbs_deb_spi("Initializing FW for Marvell WLAN 802.11 adapter "
                "(chip_id = 0x%04x, chip_rev = 0x%02x) "
                "attached to SPI bus_num %d, chip_select %d. "
                "spi->max_speed_hz=%d\n",
                card->card_id, card->card_rev,
                card->spi->master->bus_num,
                card->spi->chip_select,
                card->spi->max_speed_hz);
        err = if_spi_prog_helper_firmware(card, helper);
        if (err)
            goto out;
        err = if_spi_prog_main_firmware(card, mainfw);
        if (err)
            goto out;
        lbs_deb_spi("loaded FW for Marvell WLAN 802.11 adapter\n");
    }

    err = spu_set_interrupt_mode(card, 0, 1);
    if (err)
        goto out;

out:
    release_firmware(helper);
    release_firmware(mainfw);

    lbs_deb_leave_args(LBS_DEB_SPI, "err %d\n", err);

    return err;
}

static void if_spi_resume_worker(struct work_struct *work)
{
    struct if_spi_card *card;

    card = container_of(work, struct if_spi_card, resume_work);

    if (card->suspended) {
        if (card->pdata->setup)
            card->pdata->setup(card->spi);

        /* Init card ... */
        if_spi_init_card(card);

        enable_irq(card->spi->irq);

        /* And resume it ... */
        lbs_resume(card->priv);

        card->suspended = 0;
    }
}

static int __devinit if_spi_probe(struct spi_device *spi)
{
    struct if_spi_card *card;
    struct lbs_private *priv = NULL;
    struct libertas_spi_platform_data *pdata = spi->dev.platform_data;
    int err = 0;

    lbs_deb_enter(LBS_DEB_SPI);

    if (!pdata) {
        err = -EINVAL;
        goto out;
    }

    if (pdata->setup) {
        err = pdata->setup(spi);
        if (err)
            goto out;
    }

    /* Allocate card structure to represent this specific device */
    card = kzalloc(sizeof(struct if_spi_card), GFP_KERNEL);
    if (!card) {
        err = -ENOMEM;
        goto teardown;
    }
    spi_set_drvdata(spi, card);
    card->pdata = pdata;
    card->spi = spi;
    card->prev_xfer_time = jiffies;

    INIT_LIST_HEAD(&card->cmd_packet_list);
    INIT_LIST_HEAD(&card->data_packet_list);
    spin_lock_init(&card->buffer_lock);

    /* Initialize the SPI Interface Unit */

    /* Firmware load */
    err = if_spi_init_card(card);
    if (err)
        goto free_card;

    /*
     * Register our card with libertas.
     * This will call alloc_etherdev.
     */
    priv = lbs_add_card(card, &spi->dev);
    if (!priv) {
        err = -ENOMEM;
        goto free_card;
    }
    card->priv = priv;
    priv->setup_fw_on_resume = 1;
    priv->card = card;
    priv->hw_host_to_card = if_spi_host_to_card;
    priv->enter_deep_sleep = NULL;
    priv->exit_deep_sleep = NULL;
    priv->reset_deep_sleep_wakeup = NULL;
    priv->fw_ready = 1;

    /* Initialize interrupt handling stuff. */
    card->workqueue = create_workqueue("libertas_spi");
    INIT_WORK(&card->packet_work, if_spi_host_to_card_worker);
    INIT_WORK(&card->resume_work, if_spi_resume_worker);

    err = request_irq(spi->irq, if_spi_host_interrupt,
            IRQF_TRIGGER_FALLING, "libertas_spi", card);
    if (err) {
        pr_err("can't get host irq line-- request_irq failed\n");
        goto terminate_workqueue;
    }

    /*
     * Start the card.
     * This will call register_netdev, and we'll start
     * getting interrupts...
     */
    err = lbs_start_card(priv);
    if (err)
        goto release_irq;

    lbs_deb_spi("Finished initializing WLAN module.\n");

    /* successful exit */
    goto out;

release_irq:
    free_irq(spi->irq, card);
terminate_workqueue:
    flush_workqueue(card->workqueue);
    destroy_workqueue(card->workqueue);
    lbs_remove_card(priv); /* will call free_netdev */
free_card:
    free_if_spi_card(card);
teardown:
    if (pdata->teardown)
        pdata->teardown(spi);
out:
    lbs_deb_leave_args(LBS_DEB_SPI, "err %d\n", err);
    return err;
}

static int __devexit libertas_spi_remove(struct spi_device *spi)
{
    struct if_spi_card *card = spi_get_drvdata(spi);
    struct lbs_private *priv = card->priv;

    lbs_deb_spi("libertas_spi_remove\n");
    lbs_deb_enter(LBS_DEB_SPI);

    cancel_work_sync(&card->resume_work);

    lbs_stop_card(priv);
    lbs_remove_card(priv); /* will call free_netdev */

    free_irq(spi->irq, card);
    flush_workqueue(card->workqueue);
    destroy_workqueue(card->workqueue);
    if (card->pdata->teardown)
        card->pdata->teardown(spi);
    free_if_spi_card(card);
    lbs_deb_leave(LBS_DEB_SPI);
    return 0;
}

static int if_spi_suspend(struct device *dev)
{
    struct spi_device *spi = to_spi_device(dev);
    struct if_spi_card *card = spi_get_drvdata(spi);

    if (!card->suspended) {
        lbs_suspend(card->priv);
        flush_workqueue(card->workqueue);
        disable_irq(spi->irq);

        if (card->pdata->teardown)
            card->pdata->teardown(spi);
        card->suspended = 1;
    }

    return 0;
}

static int if_spi_resume(struct device *dev)
{
    struct spi_device *spi = to_spi_device(dev);
    struct if_spi_card *card = spi_get_drvdata(spi);

    /* Schedule delayed work */
    schedule_work(&card->resume_work);

    return 0;
}

static const struct dev_pm_ops if_spi_pm_ops = {
    .suspend    = if_spi_suspend,
    .resume     = if_spi_resume,
};

static struct spi_driver libertas_spi_driver = {
    .probe  = if_spi_probe,
    .remove = __devexit_p(libertas_spi_remove),
    .driver = {
        .name   = "libertas_spi",
        .owner  = THIS_MODULE,
        .pm = &if_spi_pm_ops,
    },
};

/*
 * Module functions
 */

static int __init if_spi_init_module(void)
{
    int ret = 0;
    lbs_deb_enter(LBS_DEB_SPI);
    printk(KERN_INFO "libertas_spi: Libertas SPI driver\n");
    ret = spi_register_driver(&libertas_spi_driver);
    lbs_deb_leave(LBS_DEB_SPI);
    return ret;
}

static void __exit if_spi_exit_module(void)
{
    lbs_deb_enter(LBS_DEB_SPI);
    spi_unregister_driver(&libertas_spi_driver);
    lbs_deb_leave(LBS_DEB_SPI);
}

module_init(if_spi_init_module);
module_exit(if_spi_exit_module);

MODULE_DESCRIPTION("Libertas SPI WLAN Driver");
MODULE_AUTHOR("Andrey Yurovsky <[email protected]>, "
          "Colin McCabe <[email protected]>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("spi:libertas_spi");