adb.c

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/*
 * Device driver for the Apple Desktop Bus
 * and the /dev/adb device on macintoshes.
 *
 * Copyright (C) 1996 Paul Mackerras.
 *
 * Modified to declare controllers as structures, added
 * client notification of bus reset and handles PowerBook
 * sleep, by Benjamin Herrenschmidt.
 *
 * To do:
 *
 * - /sys/bus/adb to list the devices and infos
 * - more /dev/adb to allow userland to receive the
 *   flow of auto-polling datas from a given device.
 * - move bus probe to a kernel thread
 */

#include <linux/types.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/adb.h>
#include <linux/cuda.h>
#include <linux/pmu.h>
#include <linux/notifier.h>
#include <linux/wait.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/device.h>
#include <linux/kthread.h>
#include <linux/platform_device.h>
#include <linux/mutex.h>

#include <asm/uaccess.h>
#ifdef CONFIG_PPC
#include <asm/prom.h>
#include <asm/machdep.h>
#endif


EXPORT_SYMBOL(adb_client_list);

extern struct adb_driver via_macii_driver;
extern struct adb_driver via_maciisi_driver;
extern struct adb_driver via_cuda_driver;
extern struct adb_driver adb_iop_driver;
extern struct adb_driver via_pmu_driver;
extern struct adb_driver macio_adb_driver;

static DEFINE_MUTEX(adb_mutex);
static struct adb_driver *adb_driver_list[] = {
#ifdef CONFIG_ADB_MACII
    &via_macii_driver,
#endif
#ifdef CONFIG_ADB_MACIISI
    &via_maciisi_driver,
#endif
#ifdef CONFIG_ADB_CUDA
    &via_cuda_driver,
#endif
#ifdef CONFIG_ADB_IOP
    &adb_iop_driver,
#endif
#if defined(CONFIG_ADB_PMU) || defined(CONFIG_ADB_PMU68K)
    &via_pmu_driver,
#endif
#ifdef CONFIG_ADB_MACIO
    &macio_adb_driver,
#endif
    NULL
};

static struct class *adb_dev_class;

static struct adb_driver *adb_controller;
BLOCKING_NOTIFIER_HEAD(adb_client_list);
static int adb_got_sleep;
static int adb_inited;
static DEFINE_SEMAPHORE(adb_probe_mutex);
static int sleepy_trackpad;
static int autopoll_devs;
int __adb_probe_sync;

static int adb_scan_bus(void);
static int do_adb_reset_bus(void);
static void adbdev_init(void);
static int try_handler_change(int, int);

static struct adb_handler {
    void (*handler)(unsigned char *, int, int);
    int original_address;
    int handler_id;
    int busy;
} adb_handler[16];

/*
 * The adb_handler_mutex mutex protects all accesses to the original_address
 * and handler_id fields of adb_handler[i] for all i, and changes to the
 * handler field.
 * Accesses to the handler field are protected by the adb_handler_lock
 * rwlock.  It is held across all calls to any handler, so that by the
 * time adb_unregister returns, we know that the old handler isn't being
 * called.
 */
static DEFINE_MUTEX(adb_handler_mutex);
static DEFINE_RWLOCK(adb_handler_lock);

#if 0
static void printADBreply(struct adb_request *req)
{
        int i;

        printk("adb reply (%d)", req->reply_len);
        for(i = 0; i < req->reply_len; i++)
                printk(" %x", req->reply[i]);
        printk("\n");

}
#endif

static int adb_scan_bus(void)
{
    int i, highFree=0, noMovement;
    int devmask = 0;
    struct adb_request req;
    
    /* assumes adb_handler[] is all zeroes at this point */
    for (i = 1; i < 16; i++) {
        /* see if there is anything at address i */
        adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
                            (i << 4) | 0xf);
        if (req.reply_len > 1)
            /* one or more devices at this address */
            adb_handler[i].original_address = i;
        else if (i > highFree)
            highFree = i;
    }

    /* Note we reset noMovement to 0 each time we move a device */
    for (noMovement = 1; noMovement < 2 && highFree > 0; noMovement++) {
        for (i = 1; i < 16; i++) {
            if (adb_handler[i].original_address == 0)
                continue;
            /*
             * Send a "talk register 3" command to address i
             * to provoke a collision if there is more than
             * one device at this address.
             */
            adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
                    (i << 4) | 0xf);
            /*
             * Move the device(s) which didn't detect a
             * collision to address `highFree'.  Hopefully
             * this only moves one device.
             */
            adb_request(&req, NULL, ADBREQ_SYNC, 3,
                    (i<< 4) | 0xb, (highFree | 0x60), 0xfe);
            /*
             * See if anybody actually moved. This is suggested
             * by HW TechNote 01:
             *
             * http://developer.apple.com/technotes/hw/hw_01.html
             */
            adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
                    (highFree << 4) | 0xf);
            if (req.reply_len <= 1) continue;
            /*
             * Test whether there are any device(s) left
             * at address i.
             */
            adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
                    (i << 4) | 0xf);
            if (req.reply_len > 1) {
                /*
                 * There are still one or more devices
                 * left at address i.  Register the one(s)
                 * we moved to `highFree', and find a new
                 * value for highFree.
                 */
                adb_handler[highFree].original_address =
                    adb_handler[i].original_address;
                while (highFree > 0 &&
                       adb_handler[highFree].original_address)
                    highFree--;
                if (highFree <= 0)
                    break;

                noMovement = 0;
            }
            else {
                /*
                 * No devices left at address i; move the
                 * one(s) we moved to `highFree' back to i.
                 */
                adb_request(&req, NULL, ADBREQ_SYNC, 3,
                        (highFree << 4) | 0xb,
                        (i | 0x60), 0xfe);
            }
        }   
    }

    /* Now fill in the handler_id field of the adb_handler entries. */
    printk(KERN_DEBUG "adb devices:");
    for (i = 1; i < 16; i++) {
        if (adb_handler[i].original_address == 0)
            continue;
        adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
                (i << 4) | 0xf);
        adb_handler[i].handler_id = req.reply[2];
        printk(" [%d]: %d %x", i, adb_handler[i].original_address,
               adb_handler[i].handler_id);
        devmask |= 1 << i;
    }
    printk("\n");
    return devmask;
}

/*
 * This kernel task handles ADB probing. It dies once probing is
 * completed.
 */
static int
adb_probe_task(void *x)
{
    printk(KERN_INFO "adb: starting probe task...\n");
    do_adb_reset_bus();
    printk(KERN_INFO "adb: finished probe task...\n");

    up(&adb_probe_mutex);

    return 0;
}

static void
__adb_probe_task(struct work_struct *bullshit)
{
    kthread_run(adb_probe_task, NULL, "kadbprobe");
}

static DECLARE_WORK(adb_reset_work, __adb_probe_task);

int
adb_reset_bus(void)
{
    if (__adb_probe_sync) {
        do_adb_reset_bus();
        return 0;
    }

    down(&adb_probe_mutex);
    schedule_work(&adb_reset_work);
    return 0;
}

#ifdef CONFIG_PM
/*
 * notify clients before sleep
 */
static int adb_suspend(struct platform_device *dev, pm_message_t state)
{
    adb_got_sleep = 1;
    /* We need to get a lock on the probe thread */
    down(&adb_probe_mutex);
    /* Stop autopoll */
    if (adb_controller->autopoll)
        adb_controller->autopoll(0);
    blocking_notifier_call_chain(&adb_client_list, ADB_MSG_POWERDOWN, NULL);

    return 0;
}

/*
 * reset bus after sleep
 */
static int adb_resume(struct platform_device *dev)
{
    adb_got_sleep = 0;
    up(&adb_probe_mutex);
    adb_reset_bus();

    return 0;
}
#endif /* CONFIG_PM */

static int __init adb_init(void)
{
    struct adb_driver *driver;
    int i;

#ifdef CONFIG_PPC32
    if (!machine_is(chrp) && !machine_is(powermac))
        return 0;
#endif
#ifdef CONFIG_MAC
    if (!MACH_IS_MAC)
        return 0;
#endif

    /* xmon may do early-init */
    if (adb_inited)
        return 0;
    adb_inited = 1;
        
    adb_controller = NULL;

    i = 0;
    while ((driver = adb_driver_list[i++]) != NULL) {
        if (!driver->probe()) {
            adb_controller = driver;
            break;
        }
    }
    if (adb_controller != NULL && adb_controller->init &&
        adb_controller->init())
        adb_controller = NULL;
    if (adb_controller == NULL) {
        printk(KERN_WARNING "Warning: no ADB interface detected\n");
    } else {
#ifdef CONFIG_PPC
        if (of_machine_is_compatible("AAPL,PowerBook1998") ||
            of_machine_is_compatible("PowerBook1,1"))
            sleepy_trackpad = 1;
#endif /* CONFIG_PPC */

        adbdev_init();
        adb_reset_bus();
    }
    return 0;
}

device_initcall(adb_init);

static int
do_adb_reset_bus(void)
{
    int ret;
    
    if (adb_controller == NULL)
        return -ENXIO;
        
    if (adb_controller->autopoll)
        adb_controller->autopoll(0);

    blocking_notifier_call_chain(&adb_client_list,
        ADB_MSG_PRE_RESET, NULL);

    if (sleepy_trackpad) {
        /* Let the trackpad settle down */
        msleep(500);
    }

    mutex_lock(&adb_handler_mutex);
    write_lock_irq(&adb_handler_lock);
    memset(adb_handler, 0, sizeof(adb_handler));
    write_unlock_irq(&adb_handler_lock);

    /* That one is still a bit synchronous, oh well... */
    if (adb_controller->reset_bus)
        ret = adb_controller->reset_bus();
    else
        ret = 0;

    if (sleepy_trackpad) {
        /* Let the trackpad settle down */
        msleep(1500);
    }

    if (!ret) {
        autopoll_devs = adb_scan_bus();
        if (adb_controller->autopoll)
            adb_controller->autopoll(autopoll_devs);
    }
    mutex_unlock(&adb_handler_mutex);

    blocking_notifier_call_chain(&adb_client_list,
        ADB_MSG_POST_RESET, NULL);
    
    return ret;
}

void
adb_poll(void)
{
    if ((adb_controller == NULL)||(adb_controller->poll == NULL))
        return;
    adb_controller->poll();
}

static void adb_sync_req_done(struct adb_request *req)
{
    struct completion *comp = req->arg;

    complete(comp);
}

int
adb_request(struct adb_request *req, void (*done)(struct adb_request *),
        int flags, int nbytes, ...)
{
    va_list list;
    int i;
    int rc;
    struct completion comp;

    if ((adb_controller == NULL) || (adb_controller->send_request == NULL))
        return -ENXIO;
    if (nbytes < 1)
        return -EINVAL;

    req->nbytes = nbytes+1;
    req->done = done;
    req->reply_expected = flags & ADBREQ_REPLY;
    req->data[0] = ADB_PACKET;
    va_start(list, nbytes);
    for (i = 0; i < nbytes; ++i)
        req->data[i+1] = va_arg(list, int);
    va_end(list);

    if (flags & ADBREQ_NOSEND)
        return 0;

    /* Synchronous requests block using an on-stack completion */
    if (flags & ADBREQ_SYNC) {
        WARN_ON(done);
        req->done = adb_sync_req_done;
        req->arg = &comp;
        init_completion(&comp);
    }

    rc = adb_controller->send_request(req, 0);

    if ((flags & ADBREQ_SYNC) && !rc && !req->complete)
        wait_for_completion(&comp);

    return rc;
}

 /* Ultimately this should return the number of devices with
    the given default id.
    And it does it now ! Note: changed behaviour: This function
    will now register if default_id _and_ handler_id both match
    but handler_id can be left to 0 to match with default_id only.
    When handler_id is set, this function will try to adjust
    the handler_id id it doesn't match. */
int
adb_register(int default_id, int handler_id, struct adb_ids *ids,
         void (*handler)(unsigned char *, int, int))
{
    int i;

    mutex_lock(&adb_handler_mutex);
    ids->nids = 0;
    for (i = 1; i < 16; i++) {
        if ((adb_handler[i].original_address == default_id) &&
            (!handler_id || (handler_id == adb_handler[i].handler_id) || 
            try_handler_change(i, handler_id))) {
            if (adb_handler[i].handler != 0) {
                printk(KERN_ERR
                       "Two handlers for ADB device %d\n",
                       default_id);
                continue;
            }
            write_lock_irq(&adb_handler_lock);
            adb_handler[i].handler = handler;
            write_unlock_irq(&adb_handler_lock);
            ids->id[ids->nids++] = i;
        }
    }
    mutex_unlock(&adb_handler_mutex);
    return ids->nids;
}

int
adb_unregister(int index)
{
    int ret = -ENODEV;

    mutex_lock(&adb_handler_mutex);
    write_lock_irq(&adb_handler_lock);
    if (adb_handler[index].handler) {
        while(adb_handler[index].busy) {
            write_unlock_irq(&adb_handler_lock);
            yield();
            write_lock_irq(&adb_handler_lock);
        }
        ret = 0;
        adb_handler[index].handler = NULL;
    }
    write_unlock_irq(&adb_handler_lock);
    mutex_unlock(&adb_handler_mutex);
    return ret;
}

void
adb_input(unsigned char *buf, int nb, int autopoll)
{
    int i, id;
    static int dump_adb_input = 0;
    unsigned long flags;
    
    void (*handler)(unsigned char *, int, int);

    /* We skip keystrokes and mouse moves when the sleep process
     * has been started. We stop autopoll, but this is another security
     */
    if (adb_got_sleep)
        return;
        
    id = buf[0] >> 4;
    if (dump_adb_input) {
        printk(KERN_INFO "adb packet: ");
        for (i = 0; i < nb; ++i)
            printk(" %x", buf[i]);
        printk(", id = %d\n", id);
    }
    write_lock_irqsave(&adb_handler_lock, flags);
    handler = adb_handler[id].handler;
    if (handler != NULL)
        adb_handler[id].busy = 1;
    write_unlock_irqrestore(&adb_handler_lock, flags);
    if (handler != NULL) {
        (*handler)(buf, nb, autopoll);
        wmb();
        adb_handler[id].busy = 0;
    }
        
}

/* Try to change handler to new_id. Will return 1 if successful. */
static int try_handler_change(int address, int new_id)
{
    struct adb_request req;

    if (adb_handler[address].handler_id == new_id)
        return 1;
    adb_request(&req, NULL, ADBREQ_SYNC, 3,
        ADB_WRITEREG(address, 3), address | 0x20, new_id);
    adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
        ADB_READREG(address, 3));
    if (req.reply_len < 2)
        return 0;
    if (req.reply[2] != new_id)
        return 0;
    adb_handler[address].handler_id = req.reply[2];

    return 1;
}

int
adb_try_handler_change(int address, int new_id)
{
    int ret;

    mutex_lock(&adb_handler_mutex);
    ret = try_handler_change(address, new_id);
    mutex_unlock(&adb_handler_mutex);
    return ret;
}

int
adb_get_infos(int address, int *original_address, int *handler_id)
{
    mutex_lock(&adb_handler_mutex);
    *original_address = adb_handler[address].original_address;
    *handler_id = adb_handler[address].handler_id;
    mutex_unlock(&adb_handler_mutex);

    return (*original_address != 0);
}


/*
 * /dev/adb device driver.
 */

#define ADB_MAJOR   56  /* major number for /dev/adb */

struct adbdev_state {
    spinlock_t  lock;
    atomic_t    n_pending;
    struct adb_request *completed;
    wait_queue_head_t wait_queue;
    int     inuse;
};

static void adb_write_done(struct adb_request *req)
{
    struct adbdev_state *state = (struct adbdev_state *) req->arg;
    unsigned long flags;

    if (!req->complete) {
        req->reply_len = 0;
        req->complete = 1;
    }
    spin_lock_irqsave(&state->lock, flags);
    atomic_dec(&state->n_pending);
    if (!state->inuse) {
        kfree(req);
        if (atomic_read(&state->n_pending) == 0) {
            spin_unlock_irqrestore(&state->lock, flags);
            kfree(state);
            return;
        }
    } else {
        struct adb_request **ap = &state->completed;
        while (*ap != NULL)
            ap = &(*ap)->next;
        req->next = NULL;
        *ap = req;
        wake_up_interruptible(&state->wait_queue);
    }
    spin_unlock_irqrestore(&state->lock, flags);
}

static int
do_adb_query(struct adb_request *req)
{
    int ret = -EINVAL;

    switch(req->data[1])
    {
    case ADB_QUERY_GETDEVINFO:
        if (req->nbytes < 3)
            break;
        mutex_lock(&adb_handler_mutex);
        req->reply[0] = adb_handler[req->data[2]].original_address;
        req->reply[1] = adb_handler[req->data[2]].handler_id;
        mutex_unlock(&adb_handler_mutex);
        req->complete = 1;
        req->reply_len = 2;
        adb_write_done(req);
        ret = 0;
        break;
    }
    return ret;
}

static int adb_open(struct inode *inode, struct file *file)
{
    struct adbdev_state *state;
    int ret = 0;

    mutex_lock(&adb_mutex);
    if (iminor(inode) > 0 || adb_controller == NULL) {
        ret = -ENXIO;
        goto out;
    }
    state = kmalloc(sizeof(struct adbdev_state), GFP_KERNEL);
    if (state == 0) {
        ret = -ENOMEM;
        goto out;
    }
    file->private_data = state;
    spin_lock_init(&state->lock);
    atomic_set(&state->n_pending, 0);
    state->completed = NULL;
    init_waitqueue_head(&state->wait_queue);
    state->inuse = 1;

out:
    mutex_unlock(&adb_mutex);
    return ret;
}

static int adb_release(struct inode *inode, struct file *file)
{
    struct adbdev_state *state = file->private_data;
    unsigned long flags;

    mutex_lock(&adb_mutex);
    if (state) {
        file->private_data = NULL;
        spin_lock_irqsave(&state->lock, flags);
        if (atomic_read(&state->n_pending) == 0
            && state->completed == NULL) {
            spin_unlock_irqrestore(&state->lock, flags);
            kfree(state);
        } else {
            state->inuse = 0;
            spin_unlock_irqrestore(&state->lock, flags);
        }
    }
    mutex_unlock(&adb_mutex);
    return 0;
}

static ssize_t adb_read(struct file *file, char __user *buf,
            size_t count, loff_t *ppos)
{
    int ret = 0;
    struct adbdev_state *state = file->private_data;
    struct adb_request *req;
    wait_queue_t wait = __WAITQUEUE_INITIALIZER(wait,current);
    unsigned long flags;

    if (count < 2)
        return -EINVAL;
    if (count > sizeof(req->reply))
        count = sizeof(req->reply);
    if (!access_ok(VERIFY_WRITE, buf, count))
        return -EFAULT;

    req = NULL;
    spin_lock_irqsave(&state->lock, flags);
    add_wait_queue(&state->wait_queue, &wait);
    set_current_state(TASK_INTERRUPTIBLE);

    for (;;) {
        req = state->completed;
        if (req != NULL)
            state->completed = req->next;
        else if (atomic_read(&state->n_pending) == 0)
            ret = -EIO;
        if (req != NULL || ret != 0)
            break;
        
        if (file->f_flags & O_NONBLOCK) {
            ret = -EAGAIN;
            break;
        }
        if (signal_pending(current)) {
            ret = -ERESTARTSYS;
            break;
        }
        spin_unlock_irqrestore(&state->lock, flags);
        schedule();
        spin_lock_irqsave(&state->lock, flags);
    }

    set_current_state(TASK_RUNNING);
    remove_wait_queue(&state->wait_queue, &wait);
    spin_unlock_irqrestore(&state->lock, flags);
    
    if (ret)
        return ret;

    ret = req->reply_len;
    if (ret > count)
        ret = count;
    if (ret > 0 && copy_to_user(buf, req->reply, ret))
        ret = -EFAULT;

    kfree(req);
    return ret;
}

static ssize_t adb_write(struct file *file, const char __user *buf,
             size_t count, loff_t *ppos)
{
    int ret/*, i*/;
    struct adbdev_state *state = file->private_data;
    struct adb_request *req;

    if (count < 2 || count > sizeof(req->data))
        return -EINVAL;
    if (adb_controller == NULL)
        return -ENXIO;
    if (!access_ok(VERIFY_READ, buf, count))
        return -EFAULT;

    req = kmalloc(sizeof(struct adb_request),
                         GFP_KERNEL);
    if (req == NULL)
        return -ENOMEM;

    req->nbytes = count;
    req->done = adb_write_done;
    req->arg = (void *) state;
    req->complete = 0;
    
    ret = -EFAULT;
    if (copy_from_user(req->data, buf, count))
        goto out;

    atomic_inc(&state->n_pending);

    /* If a probe is in progress or we are sleeping, wait for it to complete */
    down(&adb_probe_mutex);

    /* Queries are special requests sent to the ADB driver itself */
    if (req->data[0] == ADB_QUERY) {
        if (count > 1)
            ret = do_adb_query(req);
        else
            ret = -EINVAL;
        up(&adb_probe_mutex);
    }
    /* Special case for ADB_BUSRESET request, all others are sent to
       the controller */
    else if ((req->data[0] == ADB_PACKET)&&(count > 1)
        &&(req->data[1] == ADB_BUSRESET)) {
        ret = do_adb_reset_bus();
        up(&adb_probe_mutex);
        atomic_dec(&state->n_pending);
        if (ret == 0)
            ret = count;
        goto out;
    } else {    
        req->reply_expected = ((req->data[1] & 0xc) == 0xc);
        if (adb_controller && adb_controller->send_request)
            ret = adb_controller->send_request(req, 0);
        else
            ret = -ENXIO;
        up(&adb_probe_mutex);
    }

    if (ret != 0) {
        atomic_dec(&state->n_pending);
        goto out;
    }
    return count;

out:
    kfree(req);
    return ret;
}

static const struct file_operations adb_fops = {
    .owner      = THIS_MODULE,
    .llseek     = no_llseek,
    .read       = adb_read,
    .write      = adb_write,
    .open       = adb_open,
    .release    = adb_release,
};

static struct platform_driver adb_pfdrv = {
    .driver = {
        .name = "adb",
    },
#ifdef CONFIG_PM
    .suspend = adb_suspend,
    .resume = adb_resume,
#endif
};

static struct platform_device adb_pfdev = {
    .name = "adb",
};

static int __init
adb_dummy_probe(struct platform_device *dev)
{
    if (dev == &adb_pfdev)
        return 0;
    return -ENODEV;
}

static void __init
adbdev_init(void)
{
    if (register_chrdev(ADB_MAJOR, "adb", &adb_fops)) {
        printk(KERN_ERR "adb: unable to get major %d\n", ADB_MAJOR);
        return;
    }

    adb_dev_class = class_create(THIS_MODULE, "adb");
    if (IS_ERR(adb_dev_class))
        return;
    device_create(adb_dev_class, NULL, MKDEV(ADB_MAJOR, 0), NULL, "adb");

    platform_device_register(&adb_pfdev);
    platform_driver_probe(&adb_pfdrv, adb_dummy_probe);
}