p54spi.c

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/*
 * Copyright (C) 2008 Christian Lamparter <[email protected]>
 * Copyright 2008       Johannes Berg <[email protected]>
 *
 * This driver is a port from stlc45xx:
 *  Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies).
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 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 St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 */

#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/firmware.h>
#include <linux/delay.h>
#include <linux/irq.h>
#include <linux/spi/spi.h>
#include <linux/etherdevice.h>
#include <linux/gpio.h>
#include <linux/slab.h>

#include "p54spi.h"
#include "p54.h"

#include "lmac.h"

#ifdef CONFIG_P54_SPI_DEFAULT_EEPROM
#include "p54spi_eeprom.h"
#endif /* CONFIG_P54_SPI_DEFAULT_EEPROM */

MODULE_FIRMWARE("3826.arm");

/*
 * gpios should be handled in board files and provided via platform data,
 * but because it's currently impossible for p54spi to have a header file
 * in include/linux, let's use module paramaters for now
 */

static int p54spi_gpio_power = 97;
module_param(p54spi_gpio_power, int, 0444);
MODULE_PARM_DESC(p54spi_gpio_power, "gpio number for power line");

static int p54spi_gpio_irq = 87;
module_param(p54spi_gpio_irq, int, 0444);
MODULE_PARM_DESC(p54spi_gpio_irq, "gpio number for irq line");

static void p54spi_spi_read(struct p54s_priv *priv, u8 address,
                  void *buf, size_t len)
{
    struct spi_transfer t[2];
    struct spi_message m;
    __le16 addr;

    /* We first push the address */
    addr = cpu_to_le16(address << 8 | SPI_ADRS_READ_BIT_15);

    spi_message_init(&m);
    memset(t, 0, sizeof(t));

    t[0].tx_buf = &addr;
    t[0].len = sizeof(addr);
    spi_message_add_tail(&t[0], &m);

    t[1].rx_buf = buf;
    t[1].len = len;
    spi_message_add_tail(&t[1], &m);

    spi_sync(priv->spi, &m);
}


static void p54spi_spi_write(struct p54s_priv *priv, u8 address,
                 const void *buf, size_t len)
{
    struct spi_transfer t[3];
    struct spi_message m;
    __le16 addr;

    /* We first push the address */
    addr = cpu_to_le16(address << 8);

    spi_message_init(&m);
    memset(t, 0, sizeof(t));

    t[0].tx_buf = &addr;
    t[0].len = sizeof(addr);
    spi_message_add_tail(&t[0], &m);

    t[1].tx_buf = buf;
    t[1].len = len & ~1;
    spi_message_add_tail(&t[1], &m);

    if (len % 2) {
        __le16 last_word;
        last_word = cpu_to_le16(((u8 *)buf)[len - 1]);

        t[2].tx_buf = &last_word;
        t[2].len = sizeof(last_word);
        spi_message_add_tail(&t[2], &m);
    }

    spi_sync(priv->spi, &m);
}

static u32 p54spi_read32(struct p54s_priv *priv, u8 addr)
{
    __le32 val;

    p54spi_spi_read(priv, addr, &val, sizeof(val));

    return le32_to_cpu(val);
}

static inline void p54spi_write16(struct p54s_priv *priv, u8 addr, __le16 val)
{
    p54spi_spi_write(priv, addr, &val, sizeof(val));
}

static inline void p54spi_write32(struct p54s_priv *priv, u8 addr, __le32 val)
{
    p54spi_spi_write(priv, addr, &val, sizeof(val));
}

static int p54spi_wait_bit(struct p54s_priv *priv, u16 reg, u32 bits)
{
    int i;

    for (i = 0; i < 2000; i++) {
        u32 buffer = p54spi_read32(priv, reg);
        if ((buffer & bits) == bits)
            return 1;
    }
    return 0;
}

static int p54spi_spi_write_dma(struct p54s_priv *priv, __le32 base,
                const void *buf, size_t len)
{
    if (!p54spi_wait_bit(priv, SPI_ADRS_DMA_WRITE_CTRL, HOST_ALLOWED)) {
        dev_err(&priv->spi->dev, "spi_write_dma not allowed "
            "to DMA write.\n");
        return -EAGAIN;
    }

    p54spi_write16(priv, SPI_ADRS_DMA_WRITE_CTRL,
               cpu_to_le16(SPI_DMA_WRITE_CTRL_ENABLE));

    p54spi_write16(priv, SPI_ADRS_DMA_WRITE_LEN, cpu_to_le16(len));
    p54spi_write32(priv, SPI_ADRS_DMA_WRITE_BASE, base);
    p54spi_spi_write(priv, SPI_ADRS_DMA_DATA, buf, len);
    return 0;
}

static int p54spi_request_firmware(struct ieee80211_hw *dev)
{
    struct p54s_priv *priv = dev->priv;
    int ret;

    /* FIXME: should driver use it's own struct device? */
    ret = request_firmware(&priv->firmware, "3826.arm", &priv->spi->dev);

    if (ret < 0) {
        dev_err(&priv->spi->dev, "request_firmware() failed: %d", ret);
        return ret;
    }

    ret = p54_parse_firmware(dev, priv->firmware);
    if (ret) {
        release_firmware(priv->firmware);
        return ret;
    }

    return 0;
}

static int p54spi_request_eeprom(struct ieee80211_hw *dev)
{
    struct p54s_priv *priv = dev->priv;
    const struct firmware *eeprom;
    int ret;

    /*
     * allow users to customize their eeprom.
     */

    ret = request_firmware(&eeprom, "3826.eeprom", &priv->spi->dev);
    if (ret < 0) {
#ifdef CONFIG_P54_SPI_DEFAULT_EEPROM
        dev_info(&priv->spi->dev, "loading default eeprom...\n");
        ret = p54_parse_eeprom(dev, (void *) p54spi_eeprom,
                       sizeof(p54spi_eeprom));
#else
        dev_err(&priv->spi->dev, "Failed to request user eeprom\n");
#endif /* CONFIG_P54_SPI_DEFAULT_EEPROM */
    } else {
        dev_info(&priv->spi->dev, "loading user eeprom...\n");
        ret = p54_parse_eeprom(dev, (void *) eeprom->data,
                       (int)eeprom->size);
        release_firmware(eeprom);
    }
    return ret;
}

static int p54spi_upload_firmware(struct ieee80211_hw *dev)
{
    struct p54s_priv *priv = dev->priv;
    unsigned long fw_len, _fw_len;
    unsigned int offset = 0;
    int err = 0;
    u8 *fw;

    fw_len = priv->firmware->size;
    fw = kmemdup(priv->firmware->data, fw_len, GFP_KERNEL);
    if (!fw)
        return -ENOMEM;

    /* stop the device */
    p54spi_write16(priv, SPI_ADRS_DEV_CTRL_STAT, cpu_to_le16(
               SPI_CTRL_STAT_HOST_OVERRIDE | SPI_CTRL_STAT_HOST_RESET |
               SPI_CTRL_STAT_START_HALTED));

    msleep(TARGET_BOOT_SLEEP);

    p54spi_write16(priv, SPI_ADRS_DEV_CTRL_STAT, cpu_to_le16(
               SPI_CTRL_STAT_HOST_OVERRIDE |
               SPI_CTRL_STAT_START_HALTED));

    msleep(TARGET_BOOT_SLEEP);

    while (fw_len > 0) {
        _fw_len = min_t(long, fw_len, SPI_MAX_PACKET_SIZE);

        err = p54spi_spi_write_dma(priv, cpu_to_le32(
                       ISL38XX_DEV_FIRMWARE_ADDR + offset),
                       (fw + offset), _fw_len);
        if (err < 0)
            goto out;

        fw_len -= _fw_len;
        offset += _fw_len;
    }

    BUG_ON(fw_len != 0);

    /* enable host interrupts */
    p54spi_write32(priv, SPI_ADRS_HOST_INT_EN,
               cpu_to_le32(SPI_HOST_INTS_DEFAULT));

    /* boot the device */
    p54spi_write16(priv, SPI_ADRS_DEV_CTRL_STAT, cpu_to_le16(
               SPI_CTRL_STAT_HOST_OVERRIDE | SPI_CTRL_STAT_HOST_RESET |
               SPI_CTRL_STAT_RAM_BOOT));

    msleep(TARGET_BOOT_SLEEP);

    p54spi_write16(priv, SPI_ADRS_DEV_CTRL_STAT, cpu_to_le16(
               SPI_CTRL_STAT_HOST_OVERRIDE | SPI_CTRL_STAT_RAM_BOOT));
    msleep(TARGET_BOOT_SLEEP);

out:
    kfree(fw);
    return err;
}

static void p54spi_power_off(struct p54s_priv *priv)
{
    disable_irq(gpio_to_irq(p54spi_gpio_irq));
    gpio_set_value(p54spi_gpio_power, 0);
}

static void p54spi_power_on(struct p54s_priv *priv)
{
    gpio_set_value(p54spi_gpio_power, 1);
    enable_irq(gpio_to_irq(p54spi_gpio_irq));

    /*
     * need to wait a while before device can be accessed, the length
     * is just a guess
     */
    msleep(10);
}

static inline void p54spi_int_ack(struct p54s_priv *priv, u32 val)
{
    p54spi_write32(priv, SPI_ADRS_HOST_INT_ACK, cpu_to_le32(val));
}

static int p54spi_wakeup(struct p54s_priv *priv)
{
    /* wake the chip */
    p54spi_write32(priv, SPI_ADRS_ARM_INTERRUPTS,
               cpu_to_le32(SPI_TARGET_INT_WAKEUP));

    /* And wait for the READY interrupt */
    if (!p54spi_wait_bit(priv, SPI_ADRS_HOST_INTERRUPTS,
                 SPI_HOST_INT_READY)) {
        dev_err(&priv->spi->dev, "INT_READY timeout\n");
        return -EBUSY;
    }

    p54spi_int_ack(priv, SPI_HOST_INT_READY);
    return 0;
}

static inline void p54spi_sleep(struct p54s_priv *priv)
{
    p54spi_write32(priv, SPI_ADRS_ARM_INTERRUPTS,
               cpu_to_le32(SPI_TARGET_INT_SLEEP));
}

static void p54spi_int_ready(struct p54s_priv *priv)
{
    p54spi_write32(priv, SPI_ADRS_HOST_INT_EN, cpu_to_le32(
               SPI_HOST_INT_UPDATE | SPI_HOST_INT_SW_UPDATE));

    switch (priv->fw_state) {
    case FW_STATE_BOOTING:
        priv->fw_state = FW_STATE_READY;
        complete(&priv->fw_comp);
        break;
    case FW_STATE_RESETTING:
        priv->fw_state = FW_STATE_READY;
        /* TODO: reinitialize state */
        break;
    default:
        break;
    }
}

static int p54spi_rx(struct p54s_priv *priv)
{
    struct sk_buff *skb;
    u16 len;
    u16 rx_head[2];
#define READAHEAD_SZ (sizeof(rx_head)-sizeof(u16))

    if (p54spi_wakeup(priv) < 0)
        return -EBUSY;

    /* Read data size and first data word in one SPI transaction
     * This is workaround for firmware/DMA bug,
     * when first data word gets lost under high load.
     */
    p54spi_spi_read(priv, SPI_ADRS_DMA_DATA, rx_head, sizeof(rx_head));
    len = rx_head[0];

    if (len == 0) {
        p54spi_sleep(priv);
        dev_err(&priv->spi->dev, "rx request of zero bytes\n");
        return 0;
    }

    /* Firmware may insert up to 4 padding bytes after the lmac header,
     * but it does not amend the size of SPI data transfer.
     * Such packets has correct data size in header, thus referencing
     * past the end of allocated skb. Reserve extra 4 bytes for this case */
    skb = dev_alloc_skb(len + 4);
    if (!skb) {
        p54spi_sleep(priv);
        dev_err(&priv->spi->dev, "could not alloc skb");
        return -ENOMEM;
    }

    if (len <= READAHEAD_SZ) {
        memcpy(skb_put(skb, len), rx_head + 1, len);
    } else {
        memcpy(skb_put(skb, READAHEAD_SZ), rx_head + 1, READAHEAD_SZ);
        p54spi_spi_read(priv, SPI_ADRS_DMA_DATA,
                skb_put(skb, len - READAHEAD_SZ),
                len - READAHEAD_SZ);
    }
    p54spi_sleep(priv);
    /* Put additional bytes to compensate for the possible
     * alignment-caused truncation */
    skb_put(skb, 4);

    if (p54_rx(priv->hw, skb) == 0)
        dev_kfree_skb(skb);

    return 0;
}


static irqreturn_t p54spi_interrupt(int irq, void *config)
{
    struct spi_device *spi = config;
    struct p54s_priv *priv = dev_get_drvdata(&spi->dev);

    ieee80211_queue_work(priv->hw, &priv->work);

    return IRQ_HANDLED;
}

static int p54spi_tx_frame(struct p54s_priv *priv, struct sk_buff *skb)
{
    struct p54_hdr *hdr = (struct p54_hdr *) skb->data;
    int ret = 0;

    if (p54spi_wakeup(priv) < 0)
        return -EBUSY;

    ret = p54spi_spi_write_dma(priv, hdr->req_id, skb->data, skb->len);
    if (ret < 0)
        goto out;

    if (!p54spi_wait_bit(priv, SPI_ADRS_HOST_INTERRUPTS,
                 SPI_HOST_INT_WR_READY)) {
        dev_err(&priv->spi->dev, "WR_READY timeout\n");
        ret = -EAGAIN;
        goto out;
    }

    p54spi_int_ack(priv, SPI_HOST_INT_WR_READY);

    if (FREE_AFTER_TX(skb))
        p54_free_skb(priv->hw, skb);
out:
    p54spi_sleep(priv);
    return ret;
}

static int p54spi_wq_tx(struct p54s_priv *priv)
{
    struct p54s_tx_info *entry;
    struct sk_buff *skb;
    struct ieee80211_tx_info *info;
    struct p54_tx_info *minfo;
    struct p54s_tx_info *dinfo;
    unsigned long flags;
    int ret = 0;

    spin_lock_irqsave(&priv->tx_lock, flags);

    while (!list_empty(&priv->tx_pending)) {
        entry = list_entry(priv->tx_pending.next,
                   struct p54s_tx_info, tx_list);

        list_del_init(&entry->tx_list);

        spin_unlock_irqrestore(&priv->tx_lock, flags);

        dinfo = container_of((void *) entry, struct p54s_tx_info,
                     tx_list);
        minfo = container_of((void *) dinfo, struct p54_tx_info,
                     data);
        info = container_of((void *) minfo, struct ieee80211_tx_info,
                    rate_driver_data);
        skb = container_of((void *) info, struct sk_buff, cb);

        ret = p54spi_tx_frame(priv, skb);

        if (ret < 0) {
            p54_free_skb(priv->hw, skb);
            return ret;
        }

        spin_lock_irqsave(&priv->tx_lock, flags);
    }
    spin_unlock_irqrestore(&priv->tx_lock, flags);
    return ret;
}

static void p54spi_op_tx(struct ieee80211_hw *dev, struct sk_buff *skb)
{
    struct p54s_priv *priv = dev->priv;
    struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
    struct p54_tx_info *mi = (struct p54_tx_info *) info->rate_driver_data;
    struct p54s_tx_info *di = (struct p54s_tx_info *) mi->data;
    unsigned long flags;

    BUILD_BUG_ON(sizeof(*di) > sizeof((mi->data)));

    spin_lock_irqsave(&priv->tx_lock, flags);
    list_add_tail(&di->tx_list, &priv->tx_pending);
    spin_unlock_irqrestore(&priv->tx_lock, flags);

    ieee80211_queue_work(priv->hw, &priv->work);
}

static void p54spi_work(struct work_struct *work)
{
    struct p54s_priv *priv = container_of(work, struct p54s_priv, work);
    u32 ints;
    int ret;

    mutex_lock(&priv->mutex);

    if (priv->fw_state == FW_STATE_OFF)
        goto out;

    ints = p54spi_read32(priv, SPI_ADRS_HOST_INTERRUPTS);

    if (ints & SPI_HOST_INT_READY) {
        p54spi_int_ready(priv);
        p54spi_int_ack(priv, SPI_HOST_INT_READY);
    }

    if (priv->fw_state != FW_STATE_READY)
        goto out;

    if (ints & SPI_HOST_INT_UPDATE) {
        p54spi_int_ack(priv, SPI_HOST_INT_UPDATE);
        ret = p54spi_rx(priv);
        if (ret < 0)
            goto out;
    }
    if (ints & SPI_HOST_INT_SW_UPDATE) {
        p54spi_int_ack(priv, SPI_HOST_INT_SW_UPDATE);
        ret = p54spi_rx(priv);
        if (ret < 0)
            goto out;
    }

    ret = p54spi_wq_tx(priv);
out:
    mutex_unlock(&priv->mutex);
}

static int p54spi_op_start(struct ieee80211_hw *dev)
{
    struct p54s_priv *priv = dev->priv;
    unsigned long timeout;
    int ret = 0;

    if (mutex_lock_interruptible(&priv->mutex)) {
        ret = -EINTR;
        goto out;
    }

    priv->fw_state = FW_STATE_BOOTING;

    p54spi_power_on(priv);

    ret = p54spi_upload_firmware(dev);
    if (ret < 0) {
        p54spi_power_off(priv);
        goto out_unlock;
    }

    mutex_unlock(&priv->mutex);

    timeout = msecs_to_jiffies(2000);
    timeout = wait_for_completion_interruptible_timeout(&priv->fw_comp,
                                timeout);
    if (!timeout) {
        dev_err(&priv->spi->dev, "firmware boot failed");
        p54spi_power_off(priv);
        ret = -1;
        goto out;
    }

    if (mutex_lock_interruptible(&priv->mutex)) {
        ret = -EINTR;
        p54spi_power_off(priv);
        goto out;
    }

    WARN_ON(priv->fw_state != FW_STATE_READY);

out_unlock:
    mutex_unlock(&priv->mutex);

out:
    return ret;
}

static void p54spi_op_stop(struct ieee80211_hw *dev)
{
    struct p54s_priv *priv = dev->priv;
    unsigned long flags;

    mutex_lock(&priv->mutex);
    WARN_ON(priv->fw_state != FW_STATE_READY);

    p54spi_power_off(priv);
    spin_lock_irqsave(&priv->tx_lock, flags);
    INIT_LIST_HEAD(&priv->tx_pending);
    spin_unlock_irqrestore(&priv->tx_lock, flags);

    priv->fw_state = FW_STATE_OFF;
    mutex_unlock(&priv->mutex);

    cancel_work_sync(&priv->work);
}

static int __devinit p54spi_probe(struct spi_device *spi)
{
    struct p54s_priv *priv = NULL;
    struct ieee80211_hw *hw;
    int ret = -EINVAL;

    hw = p54_init_common(sizeof(*priv));
    if (!hw) {
        dev_err(&spi->dev, "could not alloc ieee80211_hw");
        return -ENOMEM;
    }

    priv = hw->priv;
    priv->hw = hw;
    dev_set_drvdata(&spi->dev, priv);
    priv->spi = spi;

    spi->bits_per_word = 16;
    spi->max_speed_hz = 24000000;

    ret = spi_setup(spi);
    if (ret < 0) {
        dev_err(&priv->spi->dev, "spi_setup failed");
        goto err_free;
    }

    ret = gpio_request(p54spi_gpio_power, "p54spi power");
    if (ret < 0) {
        dev_err(&priv->spi->dev, "power GPIO request failed: %d", ret);
        goto err_free;
    }

    ret = gpio_request(p54spi_gpio_irq, "p54spi irq");
    if (ret < 0) {
        dev_err(&priv->spi->dev, "irq GPIO request failed: %d", ret);
        goto err_free_gpio_power;
    }

    gpio_direction_output(p54spi_gpio_power, 0);
    gpio_direction_input(p54spi_gpio_irq);

    ret = request_irq(gpio_to_irq(p54spi_gpio_irq),
              p54spi_interrupt, IRQF_DISABLED, "p54spi",
              priv->spi);
    if (ret < 0) {
        dev_err(&priv->spi->dev, "request_irq() failed");
        goto err_free_gpio_irq;
    }

    irq_set_irq_type(gpio_to_irq(p54spi_gpio_irq), IRQ_TYPE_EDGE_RISING);

    disable_irq(gpio_to_irq(p54spi_gpio_irq));

    INIT_WORK(&priv->work, p54spi_work);
    init_completion(&priv->fw_comp);
    INIT_LIST_HEAD(&priv->tx_pending);
    mutex_init(&priv->mutex);
    spin_lock_init(&priv->tx_lock);
    SET_IEEE80211_DEV(hw, &spi->dev);
    priv->common.open = p54spi_op_start;
    priv->common.stop = p54spi_op_stop;
    priv->common.tx = p54spi_op_tx;

    ret = p54spi_request_firmware(hw);
    if (ret < 0)
        goto err_free_common;

    ret = p54spi_request_eeprom(hw);
    if (ret)
        goto err_free_common;

    ret = p54_register_common(hw, &priv->spi->dev);
    if (ret)
        goto err_free_common;

    return 0;

err_free_common:
    free_irq(gpio_to_irq(p54spi_gpio_irq), spi);
err_free_gpio_irq:
    gpio_free(p54spi_gpio_irq);
err_free_gpio_power:
    gpio_free(p54spi_gpio_power);
err_free:
    p54_free_common(priv->hw);
    return ret;
}

static int __devexit p54spi_remove(struct spi_device *spi)
{
    struct p54s_priv *priv = dev_get_drvdata(&spi->dev);

    p54_unregister_common(priv->hw);

    free_irq(gpio_to_irq(p54spi_gpio_irq), spi);

    gpio_free(p54spi_gpio_power);
    gpio_free(p54spi_gpio_irq);
    release_firmware(priv->firmware);

    mutex_destroy(&priv->mutex);

    p54_free_common(priv->hw);

    return 0;
}


static struct spi_driver p54spi_driver = {
    .driver = {
        .name       = "p54spi",
        .owner      = THIS_MODULE,
    },

    .probe      = p54spi_probe,
    .remove     = __devexit_p(p54spi_remove),
};

static int __init p54spi_init(void)
{
    int ret;

    ret = spi_register_driver(&p54spi_driver);
    if (ret < 0) {
        printk(KERN_ERR "failed to register SPI driver: %d", ret);
        goto out;
    }

out:
    return ret;
}

static void __exit p54spi_exit(void)
{
    spi_unregister_driver(&p54spi_driver);
}

module_init(p54spi_init);
module_exit(p54spi_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Christian Lamparter <[email protected]>");
MODULE_ALIAS("spi:cx3110x");
MODULE_ALIAS("spi:p54spi");
MODULE_ALIAS("spi:stlc45xx");