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


EXPORT_SYMBOL(adb_controller);
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 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;

struct adb_driver *adb_controller;
BLOCKING_NOTIFIER_HEAD(adb_client_list);
static int adb_got_sleep;
static int adb_inited;
static pid_t adb_probe_task_pid;
static DECLARE_MUTEX(adb_probe_mutex);
static struct completion adb_probe_task_comp;
static int sleepy_trackpad;
static int autopoll_devs;
int __adb_probe_sync;

#ifdef CONFIG_PM_SLEEP
static void adb_notify_sleep(struct pmu_sleep_notifier *self, int when);
static struct pmu_sleep_notifier adb_sleep_notifier = {
	adb_notify_sleep,
	SLEEP_LEVEL_ADB,
};
#endif

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_sem 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 DECLARE_MUTEX(adb_handler_sem);
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 __inline__ void adb_wait_ms(unsigned int ms)
{
	if (current->pid && adb_probe_task_pid &&
	  adb_probe_task_pid == current->pid)
		msleep(ms);
	else
		mdelay(ms);
}

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)
{
	strcpy(current->comm, "kadbprobe");

	printk(KERN_INFO "adb: starting probe task...\n");
	do_adb_reset_bus();
	printk(KERN_INFO "adb: finished probe task...\n");

	adb_probe_task_pid = 0;
	up(&adb_probe_mutex);

	return 0;
}

static void
__adb_probe_task(struct work_struct *bullshit)
{
	adb_probe_task_pid = kernel_thread(adb_probe_task, NULL, SIGCHLD | CLONE_KERNEL);
}

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;
}

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()) {
		printk(KERN_WARNING "Warning: no ADB interface detected\n");
		adb_controller = NULL;
	} else {
#ifdef CONFIG_PM_SLEEP
		pmu_register_sleep_notifier(&adb_sleep_notifier);
#endif /* CONFIG_PM */
#ifdef CONFIG_PPC
		if (machine_is_compatible("AAPL,PowerBook1998") ||
			machine_is_compatible("PowerBook1,1"))
			sleepy_trackpad = 1;
#endif /* CONFIG_PPC */
		init_completion(&adb_probe_task_comp);
		adbdev_init();
		adb_reset_bus();
	}
	return 0;
}

__initcall(adb_init);

#ifdef CONFIG_PM
/*
 * notify clients before sleep and reset bus afterwards
 */
void
adb_notify_sleep(struct pmu_sleep_notifier *self, int when)
{
	switch (when) {
	case PBOOK_SLEEP_REQUEST:
		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);
		break;
	case PBOOK_WAKE:
		adb_got_sleep = 0;
		up(&adb_probe_mutex);
		adb_reset_bus();
		break;
	}
}
#endif /* CONFIG_PM */

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 */
		adb_wait_ms(500);
	}

	down(&adb_handler_sem);
	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 */
		adb_wait_ms(1500);
	}

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

	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_probe_wakeup(struct adb_request *req)
{
	complete(&adb_probe_task_comp);
}

/* Static request used during probe */
static struct adb_request adb_sreq;
static unsigned long adb_sreq_lock; // Use semaphore ! */ 

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

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