ps3-vuart.c

Go to the documentation of this file.

/*
 *  PS3 virtual uart
 *
 *  Copyright (C) 2006 Sony Computer Entertainment Inc.
 *  Copyright 2006 Sony Corp.
 *
 *  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; version 2 of the License.
 *
 *  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/kernel.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/workqueue.h>
#include <linux/bitops.h>
#include <asm/ps3.h>

#include <asm/firmware.h>
#include <asm/lv1call.h>

#include "vuart.h"

MODULE_AUTHOR("Sony Corporation");
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("PS3 vuart");

enum {PORT_COUNT = 3,};

enum vuart_param {
    PARAM_TX_TRIGGER = 0,
    PARAM_RX_TRIGGER = 1,
    PARAM_INTERRUPT_MASK = 2,
    PARAM_RX_BUF_SIZE = 3, /* read only */
    PARAM_RX_BYTES = 4, /* read only */
    PARAM_TX_BUF_SIZE = 5, /* read only */
    PARAM_TX_BYTES = 6, /* read only */
    PARAM_INTERRUPT_STATUS = 7, /* read only */
};

enum vuart_interrupt_bit {
    INTERRUPT_BIT_TX = 0,
    INTERRUPT_BIT_RX = 1,
    INTERRUPT_BIT_DISCONNECT = 2,
};

enum vuart_interrupt_mask {
    INTERRUPT_MASK_TX = 1,
    INTERRUPT_MASK_RX = 2,
    INTERRUPT_MASK_DISCONNECT = 4,
};

struct ps3_vuart_port_priv {
    u64 interrupt_mask;

    struct {
        spinlock_t lock;
        struct list_head head;
    } tx_list;
    struct {
        struct ps3_vuart_work work;
        unsigned long bytes_held;
        spinlock_t lock;
        struct list_head head;
    } rx_list;
    struct ps3_vuart_stats stats;
};

static struct ps3_vuart_port_priv *to_port_priv(
    struct ps3_system_bus_device *dev)
{
    BUG_ON(!dev);
    BUG_ON(!dev->driver_priv);
    return (struct ps3_vuart_port_priv *)dev->driver_priv;
}

struct ports_bmp {
    u64 status;
    u64 unused[3];
} __attribute__((aligned(32)));

#define dump_ports_bmp(_b) _dump_ports_bmp(_b, __func__, __LINE__)
static void __maybe_unused _dump_ports_bmp(
    const struct ports_bmp *bmp, const char *func, int line)
{
    pr_debug("%s:%d: ports_bmp: %016llxh\n", func, line, bmp->status);
}

#define dump_port_params(_b) _dump_port_params(_b, __func__, __LINE__)
static void __maybe_unused _dump_port_params(unsigned int port_number,
    const char *func, int line)
{
#if defined(DEBUG)
    static const char *strings[] = {
        "tx_trigger      ",
        "rx_trigger      ",
        "interrupt_mask  ",
        "rx_buf_size     ",
        "rx_bytes        ",
        "tx_buf_size     ",
        "tx_bytes        ",
        "interrupt_status",
    };
    int result;
    unsigned int i;
    u64 value;

    for (i = 0; i < ARRAY_SIZE(strings); i++) {
        result = lv1_get_virtual_uart_param(port_number, i, &value);

        if (result) {
            pr_debug("%s:%d: port_%u: %s failed: %s\n", func, line,
                port_number, strings[i], ps3_result(result));
            continue;
        }
        pr_debug("%s:%d: port_%u: %s = %lxh\n",
            func, line, port_number, strings[i], value);
    }
#endif
}

struct vuart_triggers {
    unsigned long rx;
    unsigned long tx;
};

int ps3_vuart_get_triggers(struct ps3_system_bus_device *dev,
    struct vuart_triggers *trig)
{
    int result;
    u64 size;
    u64 val;
    u64 tx;

    result = lv1_get_virtual_uart_param(dev->port_number,
        PARAM_TX_TRIGGER, &tx);
    trig->tx = tx;

    if (result) {
        dev_dbg(&dev->core, "%s:%d: tx_trigger failed: %s\n",
            __func__, __LINE__, ps3_result(result));
        return result;
    }

    result = lv1_get_virtual_uart_param(dev->port_number,
        PARAM_RX_BUF_SIZE, &size);

    if (result) {
        dev_dbg(&dev->core, "%s:%d: tx_buf_size failed: %s\n",
            __func__, __LINE__, ps3_result(result));
        return result;
    }

    result = lv1_get_virtual_uart_param(dev->port_number,
        PARAM_RX_TRIGGER, &val);

    if (result) {
        dev_dbg(&dev->core, "%s:%d: rx_trigger failed: %s\n",
            __func__, __LINE__, ps3_result(result));
        return result;
    }

    trig->rx = size - val;

    dev_dbg(&dev->core, "%s:%d: tx %lxh, rx %lxh\n", __func__, __LINE__,
        trig->tx, trig->rx);

    return result;
}

int ps3_vuart_set_triggers(struct ps3_system_bus_device *dev, unsigned int tx,
    unsigned int rx)
{
    int result;
    u64 size;

    result = lv1_set_virtual_uart_param(dev->port_number,
        PARAM_TX_TRIGGER, tx);

    if (result) {
        dev_dbg(&dev->core, "%s:%d: tx_trigger failed: %s\n",
            __func__, __LINE__, ps3_result(result));
        return result;
    }

    result = lv1_get_virtual_uart_param(dev->port_number,
        PARAM_RX_BUF_SIZE, &size);

    if (result) {
        dev_dbg(&dev->core, "%s:%d: tx_buf_size failed: %s\n",
            __func__, __LINE__, ps3_result(result));
        return result;
    }

    result = lv1_set_virtual_uart_param(dev->port_number,
        PARAM_RX_TRIGGER, size - rx);

    if (result) {
        dev_dbg(&dev->core, "%s:%d: rx_trigger failed: %s\n",
            __func__, __LINE__, ps3_result(result));
        return result;
    }

    dev_dbg(&dev->core, "%s:%d: tx %xh, rx %xh\n", __func__, __LINE__,
        tx, rx);

    return result;
}

static int ps3_vuart_get_rx_bytes_waiting(struct ps3_system_bus_device *dev,
    u64 *bytes_waiting)
{
    int result;

    result = lv1_get_virtual_uart_param(dev->port_number,
        PARAM_RX_BYTES, bytes_waiting);

    if (result)
        dev_dbg(&dev->core, "%s:%d: rx_bytes failed: %s\n",
            __func__, __LINE__, ps3_result(result));

    dev_dbg(&dev->core, "%s:%d: %llxh\n", __func__, __LINE__,
        *bytes_waiting);
    return result;
}

static int ps3_vuart_set_interrupt_mask(struct ps3_system_bus_device *dev,
    unsigned long mask)
{
    int result;
    struct ps3_vuart_port_priv *priv = to_port_priv(dev);

    dev_dbg(&dev->core, "%s:%d: %lxh\n", __func__, __LINE__, mask);

    priv->interrupt_mask = mask;

    result = lv1_set_virtual_uart_param(dev->port_number,
        PARAM_INTERRUPT_MASK, priv->interrupt_mask);

    if (result)
        dev_dbg(&dev->core, "%s:%d: interrupt_mask failed: %s\n",
            __func__, __LINE__, ps3_result(result));

    return result;
}

static int ps3_vuart_get_interrupt_status(struct ps3_system_bus_device *dev,
    unsigned long *status)
{
    int result;
    struct ps3_vuart_port_priv *priv = to_port_priv(dev);
    u64 tmp;

    result = lv1_get_virtual_uart_param(dev->port_number,
        PARAM_INTERRUPT_STATUS, &tmp);

    if (result)
        dev_dbg(&dev->core, "%s:%d: interrupt_status failed: %s\n",
            __func__, __LINE__, ps3_result(result));

    *status = tmp & priv->interrupt_mask;

    dev_dbg(&dev->core, "%s:%d: m %llxh, s %llxh, m&s %lxh\n",
        __func__, __LINE__, priv->interrupt_mask, tmp, *status);

    return result;
}

int ps3_vuart_enable_interrupt_tx(struct ps3_system_bus_device *dev)
{
    struct ps3_vuart_port_priv *priv = to_port_priv(dev);

    return (priv->interrupt_mask & INTERRUPT_MASK_TX) ? 0
        : ps3_vuart_set_interrupt_mask(dev, priv->interrupt_mask
        | INTERRUPT_MASK_TX);
}

int ps3_vuart_enable_interrupt_rx(struct ps3_system_bus_device *dev)
{
    struct ps3_vuart_port_priv *priv = to_port_priv(dev);

    return (priv->interrupt_mask & INTERRUPT_MASK_RX) ? 0
        : ps3_vuart_set_interrupt_mask(dev, priv->interrupt_mask
        | INTERRUPT_MASK_RX);
}

int ps3_vuart_enable_interrupt_disconnect(struct ps3_system_bus_device *dev)
{
    struct ps3_vuart_port_priv *priv = to_port_priv(dev);

    return (priv->interrupt_mask & INTERRUPT_MASK_DISCONNECT) ? 0
        : ps3_vuart_set_interrupt_mask(dev, priv->interrupt_mask
        | INTERRUPT_MASK_DISCONNECT);
}

int ps3_vuart_disable_interrupt_tx(struct ps3_system_bus_device *dev)
{
    struct ps3_vuart_port_priv *priv = to_port_priv(dev);

    return (priv->interrupt_mask & INTERRUPT_MASK_TX)
        ? ps3_vuart_set_interrupt_mask(dev, priv->interrupt_mask
        & ~INTERRUPT_MASK_TX) : 0;
}

int ps3_vuart_disable_interrupt_rx(struct ps3_system_bus_device *dev)
{
    struct ps3_vuart_port_priv *priv = to_port_priv(dev);

    return (priv->interrupt_mask & INTERRUPT_MASK_RX)
        ? ps3_vuart_set_interrupt_mask(dev, priv->interrupt_mask
        & ~INTERRUPT_MASK_RX) : 0;
}

int ps3_vuart_disable_interrupt_disconnect(struct ps3_system_bus_device *dev)
{
    struct ps3_vuart_port_priv *priv = to_port_priv(dev);

    return (priv->interrupt_mask & INTERRUPT_MASK_DISCONNECT)
        ? ps3_vuart_set_interrupt_mask(dev, priv->interrupt_mask
        & ~INTERRUPT_MASK_DISCONNECT) : 0;
}

static int ps3_vuart_raw_write(struct ps3_system_bus_device *dev,
    const void *buf, unsigned int bytes, u64 *bytes_written)
{
    int result;
    struct ps3_vuart_port_priv *priv = to_port_priv(dev);

    result = lv1_write_virtual_uart(dev->port_number,
        ps3_mm_phys_to_lpar(__pa(buf)), bytes, bytes_written);

    if (result) {
        dev_dbg(&dev->core, "%s:%d: lv1_write_virtual_uart failed: "
            "%s\n", __func__, __LINE__, ps3_result(result));
        return result;
    }

    priv->stats.bytes_written += *bytes_written;

    dev_dbg(&dev->core, "%s:%d: wrote %llxh/%xh=>%lxh\n", __func__, __LINE__,
        *bytes_written, bytes, priv->stats.bytes_written);

    return result;
}

static int ps3_vuart_raw_read(struct ps3_system_bus_device *dev, void *buf,
    unsigned int bytes, u64 *bytes_read)
{
    int result;
    struct ps3_vuart_port_priv *priv = to_port_priv(dev);

    dev_dbg(&dev->core, "%s:%d: %xh\n", __func__, __LINE__, bytes);

    result = lv1_read_virtual_uart(dev->port_number,
        ps3_mm_phys_to_lpar(__pa(buf)), bytes, bytes_read);

    if (result) {
        dev_dbg(&dev->core, "%s:%d: lv1_read_virtual_uart failed: %s\n",
            __func__, __LINE__, ps3_result(result));
        return result;
    }

    priv->stats.bytes_read += *bytes_read;

    dev_dbg(&dev->core, "%s:%d: read %llxh/%xh=>%lxh\n", __func__, __LINE__,
        *bytes_read, bytes, priv->stats.bytes_read);

    return result;
}

void ps3_vuart_clear_rx_bytes(struct ps3_system_bus_device *dev,
    unsigned int bytes)
{
    int result;
    struct ps3_vuart_port_priv *priv = to_port_priv(dev);
    u64 bytes_waiting;
    void *tmp;

    result = ps3_vuart_get_rx_bytes_waiting(dev, &bytes_waiting);

    BUG_ON(result);

    bytes = bytes ? min(bytes, (unsigned int)bytes_waiting) : bytes_waiting;

    dev_dbg(&dev->core, "%s:%d: %u\n", __func__, __LINE__, bytes);

    if (!bytes)
        return;

    /* Add some extra space for recently arrived data. */

    bytes += 128;

    tmp = kmalloc(bytes, GFP_KERNEL);

    if (!tmp)
        return;

    ps3_vuart_raw_read(dev, tmp, bytes, &bytes_waiting);

    kfree(tmp);

    /* Don't include these bytes in the stats. */

    priv->stats.bytes_read -= bytes_waiting;
}
EXPORT_SYMBOL_GPL(ps3_vuart_clear_rx_bytes);

struct list_buffer {
    struct list_head link;
    const unsigned char *head;
    const unsigned char *tail;
    unsigned long dbg_number;
    unsigned char data[];
};

int ps3_vuart_write(struct ps3_system_bus_device *dev, const void *buf,
    unsigned int bytes)
{
    static unsigned long dbg_number;
    int result;
    struct ps3_vuart_port_priv *priv = to_port_priv(dev);
    unsigned long flags;
    struct list_buffer *lb;

    dev_dbg(&dev->core, "%s:%d: %u(%xh) bytes\n", __func__, __LINE__,
        bytes, bytes);

    spin_lock_irqsave(&priv->tx_list.lock, flags);

    if (list_empty(&priv->tx_list.head)) {
        u64 bytes_written;

        result = ps3_vuart_raw_write(dev, buf, bytes, &bytes_written);

        spin_unlock_irqrestore(&priv->tx_list.lock, flags);

        if (result) {
            dev_dbg(&dev->core,
                "%s:%d: ps3_vuart_raw_write failed\n",
                __func__, __LINE__);
            return result;
        }

        if (bytes_written == bytes) {
            dev_dbg(&dev->core, "%s:%d: wrote %xh bytes\n",
                __func__, __LINE__, bytes);
            return 0;
        }

        bytes -= bytes_written;
        buf += bytes_written;
    } else
        spin_unlock_irqrestore(&priv->tx_list.lock, flags);

    lb = kmalloc(sizeof(struct list_buffer) + bytes, GFP_KERNEL);

    if (!lb)
        return -ENOMEM;

    memcpy(lb->data, buf, bytes);
    lb->head = lb->data;
    lb->tail = lb->data + bytes;
    lb->dbg_number = ++dbg_number;

    spin_lock_irqsave(&priv->tx_list.lock, flags);
    list_add_tail(&lb->link, &priv->tx_list.head);
    ps3_vuart_enable_interrupt_tx(dev);
    spin_unlock_irqrestore(&priv->tx_list.lock, flags);

    dev_dbg(&dev->core, "%s:%d: queued buf_%lu, %xh bytes\n",
        __func__, __LINE__, lb->dbg_number, bytes);

    return 0;
}
EXPORT_SYMBOL_GPL(ps3_vuart_write);

static int ps3_vuart_queue_rx_bytes(struct ps3_system_bus_device *dev,
    u64 *bytes_queued)
{
    static unsigned long dbg_number;
    int result;
    struct ps3_vuart_port_priv *priv = to_port_priv(dev);
    struct list_buffer *lb;
    u64 bytes;

    *bytes_queued = 0;

    result = ps3_vuart_get_rx_bytes_waiting(dev, &bytes);
    BUG_ON(result);

    if (result)
        return -EIO;

    if (!bytes)
        return 0;

    /* Add some extra space for recently arrived data. */

    bytes += 128;

    lb = kmalloc(sizeof(struct list_buffer) + bytes, GFP_ATOMIC);

    if (!lb)
        return -ENOMEM;

    ps3_vuart_raw_read(dev, lb->data, bytes, &bytes);

    lb->head = lb->data;
    lb->tail = lb->data + bytes;
    lb->dbg_number = ++dbg_number;

    list_add_tail(&lb->link, &priv->rx_list.head);
    priv->rx_list.bytes_held += bytes;

    dev_dbg(&dev->core, "%s:%d: buf_%lu: queued %llxh bytes\n",
        __func__, __LINE__, lb->dbg_number, bytes);

    *bytes_queued = bytes;

    return 0;
}

int ps3_vuart_read(struct ps3_system_bus_device *dev, void *buf,
    unsigned int bytes)
{
    int result;
    struct ps3_vuart_port_priv *priv = to_port_priv(dev);
    unsigned long flags;
    struct list_buffer *lb, *n;
    unsigned long bytes_read;

    dev_dbg(&dev->core, "%s:%d: %u(%xh) bytes\n", __func__, __LINE__,
        bytes, bytes);

    spin_lock_irqsave(&priv->rx_list.lock, flags);

    /* Queue rx bytes here for polled reads. */

    while (priv->rx_list.bytes_held < bytes) {
        u64 tmp;

        result = ps3_vuart_queue_rx_bytes(dev, &tmp);
        if (result || !tmp) {
            dev_dbg(&dev->core, "%s:%d: starved for %lxh bytes\n",
                __func__, __LINE__,
                bytes - priv->rx_list.bytes_held);
            spin_unlock_irqrestore(&priv->rx_list.lock, flags);
            return -EAGAIN;
        }
    }

    list_for_each_entry_safe(lb, n, &priv->rx_list.head, link) {
        bytes_read = min((unsigned int)(lb->tail - lb->head), bytes);

        memcpy(buf, lb->head, bytes_read);
        buf += bytes_read;
        bytes -= bytes_read;
        priv->rx_list.bytes_held -= bytes_read;

        if (bytes_read < lb->tail - lb->head) {
            lb->head += bytes_read;
            dev_dbg(&dev->core, "%s:%d: buf_%lu: dequeued %lxh "
                "bytes\n", __func__, __LINE__, lb->dbg_number,
                bytes_read);
            spin_unlock_irqrestore(&priv->rx_list.lock, flags);
            return 0;
        }

        dev_dbg(&dev->core, "%s:%d: buf_%lu: free, dequeued %lxh "
            "bytes\n", __func__, __LINE__, lb->dbg_number,
            bytes_read);

        list_del(&lb->link);
        kfree(lb);
    }

    spin_unlock_irqrestore(&priv->rx_list.lock, flags);
    return 0;
}
EXPORT_SYMBOL_GPL(ps3_vuart_read);

static void ps3_vuart_work(struct work_struct *work)
{
    struct ps3_system_bus_device *dev =
        ps3_vuart_work_to_system_bus_dev(work);
    struct ps3_vuart_port_driver *drv =
        ps3_system_bus_dev_to_vuart_drv(dev);

    BUG_ON(!drv);
    drv->work(dev);
}

int ps3_vuart_read_async(struct ps3_system_bus_device *dev, unsigned int bytes)
{
    struct ps3_vuart_port_priv *priv = to_port_priv(dev);
    unsigned long flags;

    if (priv->rx_list.work.trigger) {
        dev_dbg(&dev->core, "%s:%d: warning, multiple calls\n",
            __func__, __LINE__);
        return -EAGAIN;
    }

    BUG_ON(!bytes);

    PREPARE_WORK(&priv->rx_list.work.work, ps3_vuart_work);

    spin_lock_irqsave(&priv->rx_list.lock, flags);
    if (priv->rx_list.bytes_held >= bytes) {
        dev_dbg(&dev->core, "%s:%d: schedule_work %xh bytes\n",
            __func__, __LINE__, bytes);
        schedule_work(&priv->rx_list.work.work);
        spin_unlock_irqrestore(&priv->rx_list.lock, flags);
        return 0;
    }

    priv->rx_list.work.trigger = bytes;
    spin_unlock_irqrestore(&priv->rx_list.lock, flags);

    dev_dbg(&dev->core, "%s:%d: waiting for %u(%xh) bytes\n", __func__,
        __LINE__, bytes, bytes);

    return 0;
}
EXPORT_SYMBOL_GPL(ps3_vuart_read_async);

void ps3_vuart_cancel_async(struct ps3_system_bus_device *dev)
{
    to_port_priv(dev)->rx_list.work.trigger = 0;
}
EXPORT_SYMBOL_GPL(ps3_vuart_cancel_async);

static int ps3_vuart_handle_interrupt_tx(struct ps3_system_bus_device *dev)
{
    int result = 0;
    struct ps3_vuart_port_priv *priv = to_port_priv(dev);
    unsigned long flags;
    struct list_buffer *lb, *n;
    unsigned long bytes_total = 0;

    dev_dbg(&dev->core, "%s:%d\n", __func__, __LINE__);

    spin_lock_irqsave(&priv->tx_list.lock, flags);

    list_for_each_entry_safe(lb, n, &priv->tx_list.head, link) {

        u64 bytes_written;

        result = ps3_vuart_raw_write(dev, lb->head, lb->tail - lb->head,
            &bytes_written);

        if (result) {
            dev_dbg(&dev->core,
                "%s:%d: ps3_vuart_raw_write failed\n",
                __func__, __LINE__);
            break;
        }

        bytes_total += bytes_written;

        if (bytes_written < lb->tail - lb->head) {
            lb->head += bytes_written;
            dev_dbg(&dev->core,
                "%s:%d cleared buf_%lu, %llxh bytes\n",
                __func__, __LINE__, lb->dbg_number,
                bytes_written);
            goto port_full;
        }

        dev_dbg(&dev->core, "%s:%d free buf_%lu\n", __func__, __LINE__,
            lb->dbg_number);

        list_del(&lb->link);
        kfree(lb);
    }

    ps3_vuart_disable_interrupt_tx(dev);
port_full:
    spin_unlock_irqrestore(&priv->tx_list.lock, flags);
    dev_dbg(&dev->core, "%s:%d wrote %lxh bytes total\n",
        __func__, __LINE__, bytes_total);
    return result;
}

static int ps3_vuart_handle_interrupt_rx(struct ps3_system_bus_device *dev)
{
    int result;
    struct ps3_vuart_port_priv *priv = to_port_priv(dev);
    unsigned long flags;
    u64 bytes;

    dev_dbg(&dev->core, "%s:%d\n", __func__, __LINE__);

    spin_lock_irqsave(&priv->rx_list.lock, flags);
    result = ps3_vuart_queue_rx_bytes(dev, &bytes);

    if (result) {
        spin_unlock_irqrestore(&priv->rx_list.lock, flags);
        return result;
    }

    if (priv->rx_list.work.trigger && priv->rx_list.bytes_held
        >= priv->rx_list.work.trigger) {
        dev_dbg(&dev->core, "%s:%d: schedule_work %lxh bytes\n",
            __func__, __LINE__, priv->rx_list.work.trigger);
        priv->rx_list.work.trigger = 0;
        schedule_work(&priv->rx_list.work.work);
    }

    spin_unlock_irqrestore(&priv->rx_list.lock, flags);
    return result;
}

static int ps3_vuart_handle_interrupt_disconnect(
    struct ps3_system_bus_device *dev)
{
    dev_dbg(&dev->core, "%s:%d\n", __func__, __LINE__);
    BUG_ON("no support");
    return -1;
}

static int ps3_vuart_handle_port_interrupt(struct ps3_system_bus_device *dev)
{
    int result;
    struct ps3_vuart_port_priv *priv = to_port_priv(dev);
    unsigned long status;

    result = ps3_vuart_get_interrupt_status(dev, &status);

    if (result)
        return result;

    dev_dbg(&dev->core, "%s:%d: status: %lxh\n", __func__, __LINE__,
        status);

    if (status & INTERRUPT_MASK_DISCONNECT) {
        priv->stats.disconnect_interrupts++;
        result = ps3_vuart_handle_interrupt_disconnect(dev);
        if (result)
            ps3_vuart_disable_interrupt_disconnect(dev);
    }

    if (status & INTERRUPT_MASK_TX) {
        priv->stats.tx_interrupts++;
        result = ps3_vuart_handle_interrupt_tx(dev);
        if (result)
            ps3_vuart_disable_interrupt_tx(dev);
    }

    if (status & INTERRUPT_MASK_RX) {
        priv->stats.rx_interrupts++;
        result = ps3_vuart_handle_interrupt_rx(dev);
        if (result)
            ps3_vuart_disable_interrupt_rx(dev);
    }

    return 0;
}

struct vuart_bus_priv {
    struct ports_bmp *bmp;
    unsigned int virq;
    struct mutex probe_mutex;
    int use_count;
    struct ps3_system_bus_device *devices[PORT_COUNT];
} static vuart_bus_priv;

static irqreturn_t ps3_vuart_irq_handler(int irq, void *_private)
{
    struct vuart_bus_priv *bus_priv = _private;

    BUG_ON(!bus_priv);

    while (1) {
        unsigned int port;

        dump_ports_bmp(bus_priv->bmp);

        port = (BITS_PER_LONG - 1) - __ilog2(bus_priv->bmp->status);

        if (port == BITS_PER_LONG)
            break;

        BUG_ON(port >= PORT_COUNT);
        BUG_ON(!bus_priv->devices[port]);

        ps3_vuart_handle_port_interrupt(bus_priv->devices[port]);
    }

    return IRQ_HANDLED;
}

static int ps3_vuart_bus_interrupt_get(void)
{
    int result;

    pr_debug(" -> %s:%d\n", __func__, __LINE__);

    vuart_bus_priv.use_count++;

    BUG_ON(vuart_bus_priv.use_count > 2);

    if (vuart_bus_priv.use_count != 1)
        return 0;

    BUG_ON(vuart_bus_priv.bmp);

    vuart_bus_priv.bmp = kzalloc(sizeof(struct ports_bmp), GFP_KERNEL);

    if (!vuart_bus_priv.bmp) {
        pr_debug("%s:%d: kzalloc failed.\n", __func__, __LINE__);
        result = -ENOMEM;
        goto fail_bmp_malloc;
    }

    result = ps3_vuart_irq_setup(PS3_BINDING_CPU_ANY, vuart_bus_priv.bmp,
        &vuart_bus_priv.virq);

    if (result) {
        pr_debug("%s:%d: ps3_vuart_irq_setup failed (%d)\n",
            __func__, __LINE__, result);
        result = -EPERM;
        goto fail_alloc_irq;
    }

    result = request_irq(vuart_bus_priv.virq, ps3_vuart_irq_handler,
        0, "vuart", &vuart_bus_priv);

    if (result) {
        pr_debug("%s:%d: request_irq failed (%d)\n",
            __func__, __LINE__, result);
        goto fail_request_irq;
    }

    pr_debug(" <- %s:%d: ok\n", __func__, __LINE__);
    return result;

fail_request_irq:
    ps3_vuart_irq_destroy(vuart_bus_priv.virq);
    vuart_bus_priv.virq = NO_IRQ;
fail_alloc_irq:
    kfree(vuart_bus_priv.bmp);
    vuart_bus_priv.bmp = NULL;
fail_bmp_malloc:
    vuart_bus_priv.use_count--;
    pr_debug(" <- %s:%d: failed\n", __func__, __LINE__);
    return result;
}

static int ps3_vuart_bus_interrupt_put(void)
{
    pr_debug(" -> %s:%d\n", __func__, __LINE__);

    vuart_bus_priv.use_count--;

    BUG_ON(vuart_bus_priv.use_count < 0);

    if (vuart_bus_priv.use_count != 0)
        return 0;

    free_irq(vuart_bus_priv.virq, &vuart_bus_priv);

    ps3_vuart_irq_destroy(vuart_bus_priv.virq);
    vuart_bus_priv.virq = NO_IRQ;

    kfree(vuart_bus_priv.bmp);
    vuart_bus_priv.bmp = NULL;

    pr_debug(" <- %s:%d\n", __func__, __LINE__);
    return 0;
}

static int ps3_vuart_probe(struct ps3_system_bus_device *dev)
{
    int result;
    struct ps3_vuart_port_driver *drv;
    struct ps3_vuart_port_priv *priv = NULL;

    dev_dbg(&dev->core, "%s:%d\n", __func__, __LINE__);

    drv = ps3_system_bus_dev_to_vuart_drv(dev);

    dev_dbg(&dev->core, "%s:%d: (%s)\n", __func__, __LINE__,
        drv->core.core.name);

    BUG_ON(!drv);

    if (dev->port_number >= PORT_COUNT) {
        BUG();
        return -EINVAL;
    }

    mutex_lock(&vuart_bus_priv.probe_mutex);

    result = ps3_vuart_bus_interrupt_get();

    if (result)
        goto fail_setup_interrupt;

    if (vuart_bus_priv.devices[dev->port_number]) {
        dev_dbg(&dev->core, "%s:%d: port busy (%d)\n", __func__,
            __LINE__, dev->port_number);
        result = -EBUSY;
        goto fail_busy;
    }

    vuart_bus_priv.devices[dev->port_number] = dev;

    /* Setup dev->driver_priv. */

    dev->driver_priv = kzalloc(sizeof(struct ps3_vuart_port_priv),
        GFP_KERNEL);

    if (!dev->driver_priv) {
        result = -ENOMEM;
        goto fail_dev_malloc;
    }

    priv = to_port_priv(dev);

    INIT_LIST_HEAD(&priv->tx_list.head);
    spin_lock_init(&priv->tx_list.lock);

    INIT_LIST_HEAD(&priv->rx_list.head);
    spin_lock_init(&priv->rx_list.lock);

    INIT_WORK(&priv->rx_list.work.work, NULL);
    priv->rx_list.work.trigger = 0;
    priv->rx_list.work.dev = dev;

    /* clear stale pending interrupts */

    ps3_vuart_clear_rx_bytes(dev, 0);

    ps3_vuart_set_interrupt_mask(dev, INTERRUPT_MASK_RX);

    ps3_vuart_set_triggers(dev, 1, 1);

    if (drv->probe)
        result = drv->probe(dev);
    else {
        result = 0;
        dev_info(&dev->core, "%s:%d: no probe method\n", __func__,
            __LINE__);
    }

    if (result) {
        dev_dbg(&dev->core, "%s:%d: drv->probe failed\n",
            __func__, __LINE__);
        goto fail_probe;
    }

    mutex_unlock(&vuart_bus_priv.probe_mutex);

    return result;

fail_probe:
    ps3_vuart_set_interrupt_mask(dev, 0);
    kfree(dev->driver_priv);
    dev->driver_priv = NULL;
fail_dev_malloc:
    vuart_bus_priv.devices[dev->port_number] = NULL;
fail_busy:
    ps3_vuart_bus_interrupt_put();
fail_setup_interrupt:
    mutex_unlock(&vuart_bus_priv.probe_mutex);
    dev_dbg(&dev->core, "%s:%d: failed\n", __func__, __LINE__);
    return result;
}

static int ps3_vuart_cleanup(struct ps3_system_bus_device *dev)
{
    dev_dbg(&dev->core, "%s:%d\n", __func__, __LINE__);

    ps3_vuart_cancel_async(dev);
    ps3_vuart_set_interrupt_mask(dev, 0);
    ps3_vuart_bus_interrupt_put();
    return 0;
}

static int ps3_vuart_remove(struct ps3_system_bus_device *dev)
{
    struct ps3_vuart_port_priv *priv = to_port_priv(dev);
    struct ps3_vuart_port_driver *drv;

    BUG_ON(!dev);

    mutex_lock(&vuart_bus_priv.probe_mutex);

    dev_dbg(&dev->core, " -> %s:%d: match_id %d\n", __func__, __LINE__,
        dev->match_id);

    if (!dev->core.driver) {
        dev_dbg(&dev->core, "%s:%d: no driver bound\n", __func__,
            __LINE__);
        mutex_unlock(&vuart_bus_priv.probe_mutex);
        return 0;
    }

    drv = ps3_system_bus_dev_to_vuart_drv(dev);

    BUG_ON(!drv);

    if (drv->remove) {
        drv->remove(dev);
    } else {
        dev_dbg(&dev->core, "%s:%d: no remove method\n", __func__,
        __LINE__);
        BUG();
    }

    ps3_vuart_cleanup(dev);

    vuart_bus_priv.devices[dev->port_number] = NULL;
    kfree(priv);
    priv = NULL;

    dev_dbg(&dev->core, " <- %s:%d\n", __func__, __LINE__);
    mutex_unlock(&vuart_bus_priv.probe_mutex);
    return 0;
}

static int ps3_vuart_shutdown(struct ps3_system_bus_device *dev)
{
    struct ps3_vuart_port_driver *drv;

    BUG_ON(!dev);

    mutex_lock(&vuart_bus_priv.probe_mutex);

    dev_dbg(&dev->core, " -> %s:%d: match_id %d\n", __func__, __LINE__,
        dev->match_id);

    if (!dev->core.driver) {
        dev_dbg(&dev->core, "%s:%d: no driver bound\n", __func__,
            __LINE__);
        mutex_unlock(&vuart_bus_priv.probe_mutex);
        return 0;
    }

    drv = ps3_system_bus_dev_to_vuart_drv(dev);

    BUG_ON(!drv);

    if (drv->shutdown)
        drv->shutdown(dev);
    else if (drv->remove) {
        dev_dbg(&dev->core, "%s:%d: no shutdown, calling remove\n",
            __func__, __LINE__);
        drv->remove(dev);
    } else {
        dev_dbg(&dev->core, "%s:%d: no shutdown method\n", __func__,
            __LINE__);
        BUG();
    }

    ps3_vuart_cleanup(dev);

    dev_dbg(&dev->core, " <- %s:%d\n", __func__, __LINE__);

    mutex_unlock(&vuart_bus_priv.probe_mutex);
    return 0;
}

static int __init ps3_vuart_bus_init(void)
{
    pr_debug("%s:%d:\n", __func__, __LINE__);

    if (!firmware_has_feature(FW_FEATURE_PS3_LV1))
        return -ENODEV;

    mutex_init(&vuart_bus_priv.probe_mutex);

    return 0;
}

static void __exit ps3_vuart_bus_exit(void)
{
    pr_debug("%s:%d:\n", __func__, __LINE__);
}

core_initcall(ps3_vuart_bus_init);
module_exit(ps3_vuart_bus_exit);

int ps3_vuart_port_driver_register(struct ps3_vuart_port_driver *drv)
{
    int result;

    pr_debug("%s:%d: (%s)\n", __func__, __LINE__, drv->core.core.name);

    BUG_ON(!drv->core.match_id);
    BUG_ON(!drv->core.core.name);

    drv->core.probe = ps3_vuart_probe;
    drv->core.remove = ps3_vuart_remove;
    drv->core.shutdown = ps3_vuart_shutdown;

    result = ps3_system_bus_driver_register(&drv->core);
    return result;
}
EXPORT_SYMBOL_GPL(ps3_vuart_port_driver_register);

void ps3_vuart_port_driver_unregister(struct ps3_vuart_port_driver *drv)
{
    pr_debug("%s:%d: (%s)\n", __func__, __LINE__, drv->core.core.name);
    ps3_system_bus_driver_unregister(&drv->core);
}
EXPORT_SYMBOL_GPL(ps3_vuart_port_driver_unregister);