patch-2.2.7 linux/drivers/usb/uhci.c

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diff -u --recursive --new-file v2.2.6/linux/drivers/usb/uhci.c linux/drivers/usb/uhci.c
@@ -0,0 +1,1202 @@
+/*
+ * Universal Host Controller Interface driver for USB.
+ *
+ * (C) Copyright 1999 Linus Torvalds
+ *
+ * Intel documents this fairly well, and as far as I know there
+ * are no royalties or anything like that, but even so there are
+ * people who decided that they want to do the same thing in a
+ * completely different way.
+ *
+ * Oh, well. The intel version is the more common by far. As such,
+ * that's the one I care about right now.
+ *
+ * WARNING! The USB documentation is downright evil. Most of it
+ * is just crap, written by a committee. You're better off ignoring
+ * most of it, the important stuff is:
+ *  - the low-level protocol (fairly simple but lots of small details)
+ *  - working around the horridness of the rest
+ */
+
+/* 4/4/1999 added data toggle for interrupt pipes -keryan */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/ioport.h>
+#include <linux/sched.h>
+#include <linux/malloc.h>
+#include <linux/smp_lock.h>
+#include <linux/errno.h>
+
+#include <asm/spinlock.h>
+#include <asm/io.h>
+#include <asm/irq.h>
+#include <asm/system.h>
+
+#include "uhci.h"
+#include "inits.h"
+
+#ifdef CONFIG_APM
+#include <linux/apm_bios.h>
+static int handle_apm_event(apm_event_t event);
+static int apm_resume = 0;
+#endif
+
+#define compile_assert(x) do { switch (0) { case 1: case !(x): } } while (0)
+
+int usb_mouse_init(void);
+int hub_init(void);
+
+static struct wait_queue *uhci_configure = NULL;
+
+/*
+ * Return the result of a TD..
+ */
+static int uhci_td_result(struct uhci_device *dev, struct uhci_td *td)
+{
+	unsigned int status;
+
+	status = (td->status >> 16) & 0xff;
+
+	/* Some debugging code */
+	if (status) {
+		int i = 10;
+		struct uhci_td *tmp = dev->control_td;
+		printk("uhci_td_result() failed with status %d\n", status);
+		show_status(dev->uhci);
+		do {
+			show_td(tmp);
+			tmp++;
+			if (!--i)
+				break;
+		} while (tmp <= td);
+	}
+	return status;		
+}
+
+/*
+ * Inserts a td into qh list at the top.
+ *
+ * Careful about atomicity: even on UP this
+ * requires a locked access due to the concurrent
+ * DMA engine.
+ *
+ * NOTE! This assumes that first->last is a valid
+ * list of TD's with the proper backpointers set
+ * up and all..
+ */
+static void uhci_insert_tds_in_qh(struct uhci_qh *qh, struct uhci_td *first, struct uhci_td *last)
+{
+	unsigned int link = qh->element;
+	unsigned int new = 4 | virt_to_bus(first);
+
+	for (;;) {
+		unsigned char success;
+
+		last->link = link;
+		first->backptr = &qh->element;
+		asm volatile("lock ; cmpxchg %4,%2 ; sete %0"
+			:"=q" (success), "=a" (link)
+			:"m" (qh->element), "1" (link), "r" (new)
+			:"memory");
+		if (success) {
+			/* Was there a successor entry? Fix it's backpointer.. */
+			if ((link & 1) == 0) {
+				struct uhci_td *next = bus_to_virt(link & ~15);
+				next->backptr = &last->link;
+			}
+			break;
+		}
+	}
+}
+
+static inline void uhci_insert_td_in_qh(struct uhci_qh *qh, struct uhci_td *td)
+{
+	uhci_insert_tds_in_qh(qh, td, td);
+}
+
+static void uhci_insert_qh(struct uhci_qh *qh, struct uhci_qh *newqh)
+{
+	newqh->link = qh->link;
+	qh->link = virt_to_bus(newqh) | 2;
+}
+
+static void uhci_remove_qh(struct uhci_qh *qh, struct uhci_qh *remqh)
+{
+	unsigned int remphys = virt_to_bus(remqh);
+	struct uhci_qh *lqh = qh;
+
+	while ((lqh->link & ~0xF) != remphys) {
+		if (lqh->link & 1)
+			break;
+
+		lqh = bus_to_virt(lqh->link & ~0xF);
+	}
+
+	if (lqh->link & 1) {
+		printk("couldn't find qh in chain!\n");
+		return;
+	}
+
+	lqh->link = remqh->link;
+}
+
+/*
+ * Removes td from qh if present.
+ *
+ * NOTE! We keep track of both forward and back-pointers,
+ * so this should be trivial, right?
+ *
+ * Wrong. While all TD insert/remove operations are synchronous
+ * on the CPU, the UHCI controller can (and does) play with the
+ * very first forward pointer. So we need to validate the backptr
+ * before we change it, so that we don't by mistake reset the QH
+ * head to something old.
+ */
+static void uhci_remove_td(struct uhci_td *td)
+{
+	unsigned int *backptr = td->backptr;
+	unsigned int link = td->link;
+	unsigned int me;
+
+	if (!backptr)
+		return;
+
+	td->backptr = NULL;
+
+	/*
+	 * This is the easy case: the UHCI will never change "td->link",
+	 * so we can always just look at that and fix up the backpointer
+	 * of any next element..
+	 */
+	if (!(link & 1)) {
+		struct uhci_td *next = bus_to_virt(link & ~15);
+		next->backptr = backptr;
+	}
+
+	/*
+	 * The nasty case is "backptr->next", which we need to
+	 * update to "link" _only_ if "backptr" still points
+	 * to us (it may not: maybe backptr is a QH->element
+	 * pointer and the UHCI has changed the value).
+	 */
+	me = virt_to_bus(td) | (0xe & *backptr);
+	asm volatile("lock ; cmpxchg %0,%1"
+		:
+		:"r" (link), "m" (*backptr), "a" (me)
+		:"memory");
+}
+
+static struct uhci_qh *uhci_qh_allocate(struct uhci_device *dev)
+{
+	struct uhci_qh *qh;
+	int inuse;
+
+	qh = dev->qh;
+	for (; (inuse = test_and_set_bit(0, &qh->inuse)) != 0 && qh < &dev->qh[UHCI_MAXQH]; qh++)
+		;
+
+	if (!inuse)
+		return(qh);
+
+	printk("ran out of qh's for dev %p\n", dev);
+	return(NULL);
+}
+
+static void uhci_qh_deallocate(struct uhci_qh *qh)
+{
+	if (qh->element != 1)
+		printk("qh %p leaving dangling entries? (%X)\n", qh, qh->element);
+
+	qh->element = 1;
+	qh->link = 1;
+
+	clear_bit(0, &qh->inuse);
+}
+
+static struct uhci_td *uhci_td_allocate(struct uhci_device *dev)
+{
+	struct uhci_td *td;
+	int inuse;
+
+	td = dev->td;
+	for (; (inuse = test_and_set_bit(0, &td->inuse)) != 0 && td < &dev->td[UHCI_MAXTD]; td++)
+		;
+
+	if (!inuse)
+		return(td);
+
+	printk("ran out of td's for dev %p\n", dev);
+	return(NULL);
+}
+
+/*
+ * This MUST only be called when it has been removed from a QH already (or
+ * the QH has been removed from the skeleton
+ */
+static void uhci_td_deallocate(struct uhci_td *td)
+{
+	td->link = 1;
+
+	clear_bit(0, &td->inuse);
+}
+
+/*
+ * UHCI interrupt list operations..
+ */
+static spinlock_t irqlist_lock = SPIN_LOCK_UNLOCKED;
+
+static void uhci_add_irq_list(struct uhci *uhci, struct uhci_td *td, usb_device_irq completed, void *dev_id)
+{
+	unsigned long flags;
+
+	td->completed = completed;
+	td->dev_id = dev_id;
+
+	spin_lock_irqsave(&irqlist_lock, flags);
+	list_add(&td->irq_list, &uhci->interrupt_list);
+	spin_unlock_irqrestore(&irqlist_lock, flags);
+}
+
+static void uhci_remove_irq_list(struct uhci_td *td)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&irqlist_lock, flags);
+	list_del(&td->irq_list);
+	spin_unlock_irqrestore(&irqlist_lock, flags);
+}
+
+/*
+ * Request a interrupt handler..
+ */
+static int uhci_request_irq(struct usb_device *usb_dev, unsigned int pipe, usb_device_irq handler, int period, void *dev_id)
+{
+	struct uhci_device *dev = usb_to_uhci(usb_dev);
+	struct uhci_td *td = uhci_td_allocate(dev);
+	struct uhci_qh *interrupt_qh = uhci_qh_allocate(dev);
+
+	unsigned int destination, status;
+
+	/* Destination: pipe destination with INPUT */
+	destination = (pipe & 0x0007ff00)  |  0x69;
+
+	/* Status:    slow/fast,      Interrupt,   Active,    Short Packet Detect     Infinite Errors */
+	status = (pipe & (1 << 26)) | (1 << 24) | (1 << 23)   |   (1 << 29)       |    (0 << 27);
+
+	if(interrupt_qh->element != 1)
+		printk("interrupt_qh->element = 0x%x\n", 
+		       interrupt_qh->element);
+
+	td->link = 1;
+	td->status = status;			/* In */
+	td->info = destination | (7 << 21);	/* 8 bytes of data */
+	td->buffer = virt_to_bus(dev->data);
+	td->qh = interrupt_qh;
+	interrupt_qh->skel = &dev->uhci->root_hub->skel_int8_qh;
+
+	uhci_add_irq_list(dev->uhci, td, handler, dev_id);
+
+	uhci_insert_td_in_qh(interrupt_qh, td);
+
+	/* Add it into the skeleton */
+	uhci_insert_qh(&dev->uhci->root_hub->skel_int8_qh, interrupt_qh);
+	return 0;
+}
+
+/*
+ * Control thread operations: we just mark the last TD
+ * in a control thread as an interrupt TD, and wake up
+ * the front-end on completion.
+ *
+ * We need to remove the TD from the lists (both interrupt
+ * list and TD lists) by hand if something bad happens!
+ */
+static struct wait_queue *control_wakeup;
+
+static int uhci_control_completed(int status, void *buffer, void *dev_id)
+{
+	wake_up(&control_wakeup);
+	return 0;			/* Don't re-instate */
+}
+
+/* td points to the last td in the list, which interrupts on completion */
+static int uhci_run_control(struct uhci_device *dev, struct uhci_td *first, struct uhci_td *last)
+{
+	struct wait_queue wait = { current, NULL };
+	struct uhci_qh *ctrl_qh = uhci_qh_allocate(dev);
+	struct uhci_td *curtd;
+
+	current->state = TASK_UNINTERRUPTIBLE;
+	add_wait_queue(&control_wakeup, &wait);
+
+	uhci_add_irq_list(dev->uhci, last, uhci_control_completed, NULL);
+	
+	/* FIXME: This is kinda kludged */
+	/* Walk the TD list and update the QH pointer */
+	{
+	int maxcount = 100;
+
+	curtd = first;
+	do {
+		curtd->qh = ctrl_qh;
+		if (curtd->link & 1)
+			break;
+
+		curtd = bus_to_virt(curtd->link & ~0xF);
+		if (!--maxcount) {
+			printk("runaway tds!\n");
+			break;
+		}
+	} while (1);
+	}
+
+	uhci_insert_tds_in_qh(ctrl_qh, first, last);
+
+	/* Add it into the skeleton */
+	uhci_insert_qh(&dev->uhci->root_hub->skel_control_qh, ctrl_qh);
+
+	schedule_timeout(HZ/10);
+
+	remove_wait_queue(&control_wakeup, &wait);
+
+	/* Clean up in case it failed.. */
+	uhci_remove_irq_list(last);
+
+#if 0
+	printk("Looking for tds [%p, %p]\n", dev->control_td, td);
+#endif
+
+	/* Remove it from the skeleton */
+	uhci_remove_qh(&dev->uhci->root_hub->skel_control_qh, ctrl_qh);
+
+	uhci_qh_deallocate(ctrl_qh);
+
+	return uhci_td_result(dev, last);
+}
+
+/*
+ * Send or receive a control message on a pipe.
+ *
+ * Note that the "pipe" structure is set up to map
+ * easily to the uhci destination fields.
+ *
+ * A control message is built up from three parts:
+ *  - The command itself
+ *  - [ optional ] data phase
+ *  - Status complete phase
+ *
+ * The data phase can be an arbitrary number of TD's
+ * although we currently had better not have more than
+ * 29 TD's here (we have 31 TD's allocated for control
+ * operations, and two of them are used for command and
+ * status).
+ *
+ * 29 TD's is a minimum of 232 bytes worth of control
+ * information, that's just ridiculously high. Most
+ * control messages have just a few bytes of data.
+ */
+static int uhci_control_msg(struct usb_device *usb_dev, unsigned int pipe, void *cmd, void *data, int len)
+{
+	struct uhci_device *dev = usb_to_uhci(usb_dev);
+	struct uhci_td *first, *td, *prevtd;
+	unsigned long destination, status;
+	int ret;
+
+	if (len > usb_maxpacket(usb_dev->maxpacketsize) * 29)
+		printk("Warning, too much data for a control packet, crashing\n");
+
+	first = td = uhci_td_allocate(dev);
+
+	/* The "pipe" thing contains the destination in bits 8--18, 0x2D is SETUP */
+	destination = (pipe & 0x0007ff00) | 0x2D;
+
+	/* Status:    slow/fast,       Active,    Short Packet Detect     Three Errors */
+	status = (pipe & (1 << 26)) | (1 << 23)   |   (1 << 29)       |    (3 << 27);
+
+	/*
+	 * Build the TD for the control request
+	 */
+	td->status = status;				/* Try forever */
+	td->info = destination | (7 << 21);		/* 8 bytes of data */
+	td->buffer = virt_to_bus(cmd);
+
+	/*
+	 * If direction is "send", change the frame from SETUP (0x2D)
+	 * to OUT (0xE1). Else change it from SETUP to IN (0x69)
+	 */
+	destination ^= (0x2D ^ 0x69);			/* SETUP -> IN */
+	if (usb_pipeout(pipe))
+		destination ^= (0xE1 ^ 0x69);		/* IN -> OUT */
+
+	prevtd = td;
+	td = uhci_td_allocate(dev);
+	prevtd->link = 4 | virt_to_bus(td);
+
+	/*
+	 * Build the DATA TD's
+	 */
+	while (len > 0) {
+		/* Build the TD for control status */
+		int pktsze = len;
+		int maxsze = usb_maxpacket(pipe);
+
+		if (pktsze > maxsze)
+			pktsze = maxsze;
+
+		/* Alternate Data0/1 (start with Data1) */
+		destination ^= 1 << 19;
+	
+		td->status = status;					/* Status */
+		td->info = destination | ((pktsze-1) << 21);		/* pktsze bytes of data */
+		td->buffer = virt_to_bus(data);
+		td->backptr = &prevtd->link;
+
+		prevtd = td;
+		td = uhci_td_allocate(dev);
+		prevtd->link = 4 | virt_to_bus(td);			/* Update previous TD */
+
+		data += maxsze;
+		len -= maxsze;
+	}
+
+	/*
+	 * Build the final TD for control status
+	 */
+	destination ^= (0xE1 ^ 0x69);			/* OUT -> IN */
+	destination |= 1 << 19;				/* End in Data1 */
+
+	td->link = 1;					/* Terminate */
+	td->status = status | (1 << 24);		/* IOC */
+	td->info = destination | (0x7ff << 21);		/* 0 bytes of data */
+	td->buffer = 0;
+	td->backptr = &prevtd->link;
+
+	/* Start it up.. */
+	ret = uhci_run_control(dev, first, td);
+
+	{
+		int maxcount = 100;
+		struct uhci_td *curtd = first;
+		unsigned int nextlink;
+
+		do {
+			nextlink = curtd->link;
+			uhci_remove_td(curtd);
+			uhci_td_deallocate(curtd);
+			if (nextlink & 1)	/* Tail? */
+				break;
+
+			curtd = bus_to_virt(nextlink & ~0xF);
+			if (!--maxcount) {
+				printk("runaway td's!?\n");
+				break;
+			}
+		} while (1);
+	}
+
+	return ret;
+}
+
+static struct usb_device *uhci_usb_allocate(struct usb_device *parent)
+{
+	struct usb_device *usb_dev;
+	struct uhci_device *dev;
+	int i;
+
+	usb_dev = kmalloc(sizeof(*usb_dev), GFP_KERNEL);
+	if (!usb_dev)
+		return NULL;
+
+	memset(usb_dev, 0, sizeof(*usb_dev));
+
+	dev = kmalloc(sizeof(*dev), GFP_KERNEL);
+	if (!dev) {
+		kfree(usb_dev);
+		return NULL;
+	}
+
+	/* Initialize "dev" */
+	memset(dev, 0, sizeof(*dev));
+
+	usb_dev->hcpriv = dev;
+	dev->usb = usb_dev;
+
+	usb_dev->parent = parent;
+
+	if (parent) {
+		usb_dev->bus = parent->bus;
+		dev->uhci = usb_to_uhci(parent)->uhci;
+	}
+
+	/* Reset the QH's and TD's */
+	for (i = 0; i < UHCI_MAXQH; i++) {
+		dev->qh[i].link = 1;
+		dev->qh[i].element = 1;
+		dev->qh[i].inuse = 0;
+	}
+
+	for (i = 0; i < UHCI_MAXTD; i++) {
+		dev->td[i].link = 1;
+		dev->td[i].inuse = 0;
+	}
+
+	return usb_dev;
+}
+
+static int uhci_usb_deallocate(struct usb_device *usb_dev)
+{
+	struct uhci_device *dev = usb_to_uhci(usb_dev);
+	int i;
+
+	/* There are UHCI_MAXTD preallocated tds */
+	for (i = 0; i < UHCI_MAXTD; ++i) {
+		struct uhci_td *td = dev->td + i;
+
+		/* And remove it from the irq list, if it's active */
+		if (td->status & (1 << 23))
+			uhci_remove_irq_list(td);
+
+		if (td->inuse)
+			uhci_remove_td(td);
+	}
+
+	/* Remove the td from any queues */
+	for (i = 0; i < UHCI_MAXQH; ++i) {
+		struct uhci_qh *qh = dev->qh + i;
+
+		if (qh->inuse)
+			uhci_remove_qh(qh->skel, qh);
+	}
+
+	kfree(dev);
+	kfree(usb_dev);
+
+	return 0;
+}
+
+struct usb_operations uhci_device_operations = {
+	uhci_usb_allocate,
+	uhci_usb_deallocate,
+	uhci_control_msg,
+	uhci_request_irq,
+};
+
+/*
+ * This is just incredibly fragile. The timings must be just
+ * right, and they aren't really documented very well.
+ *
+ * Note the short delay between disabling reset and enabling
+ * the port..
+ */
+static void uhci_reset_port(unsigned int port)
+{
+	unsigned short status;
+
+	status = inw(port);
+	outw(status | USBPORTSC_PR, port);		/* reset port */
+	wait_ms(10);
+	outw(status & ~USBPORTSC_PR, port);
+	udelay(5);
+
+	status = inw(port);
+	outw(status | USBPORTSC_PE, port);		/* enable port */
+	wait_ms(10);
+
+	status = inw(port);
+	if(!(status & USBPORTSC_PE)) {
+		outw(status | USBPORTSC_PE, port);	/* one more try at enabling port */
+		wait_ms(50);
+	}
+
+}
+
+
+/*
+ * This gets called if the connect status on the root
+ * hub (and the root hub only) changes.
+ */
+static void uhci_connect_change(struct uhci *uhci, unsigned int port, unsigned int nr)
+{
+	struct usb_device *usb_dev;
+	struct uhci_device *dev;
+	unsigned short status;
+
+	printk("uhci_connect_change: called for %d\n", nr);
+
+	/*
+	 * Even if the status says we're connected,
+	 * the fact that the status bits changed may
+	 * that we got disconnected and then reconnected.
+	 *
+	 * So start off by getting rid of any old devices..
+	 */
+	usb_disconnect(&uhci->root_hub->usb->children[nr]);
+
+	status = inw(port);
+
+	/* If we have nothing connected, then clear change status and disable the port */
+	status = (status & ~USBPORTSC_PE) | USBPORTSC_PEC;
+	if (!(status & USBPORTSC_CCS)) {
+		outw(status, port);
+		return;
+	}
+
+	/*
+	 * Ok, we got a new connection. Allocate a device to it,
+	 * and find out what it wants to do..
+	 */
+	usb_dev = uhci_usb_allocate(uhci->root_hub->usb);
+	dev = usb_dev->hcpriv;
+
+	dev->uhci = uhci;
+
+	usb_connect(usb_dev);
+
+	uhci->root_hub->usb->children[nr] = usb_dev;
+
+	wait_ms(200); /* wait for powerup */
+	uhci_reset_port(port);
+
+	/* Get speed information */
+	usb_dev->slow = (inw(port) & USBPORTSC_LSDA) ? 1 : 0;
+
+	/*
+	 * Ok, all the stuff specific to the root hub has been done.
+	 * The rest is generic for any new USB attach, regardless of
+	 * hub type.
+	 */
+	usb_new_device(usb_dev);
+}
+
+/*
+ * This gets called when the root hub configuration
+ * has changed. Just go through each port, seeing if
+ * there is something interesting happening.
+ */
+static void uhci_check_configuration(struct uhci *uhci)
+{
+	unsigned int io_addr = uhci->io_addr + USBPORTSC1;
+	int maxchild = uhci->root_hub->usb->maxchild;
+	int nr = 0;
+
+	do {
+		unsigned short status = inw(io_addr);
+
+		if (status & USBPORTSC_CSC)
+			uhci_connect_change(uhci, io_addr, nr);
+
+		nr++; io_addr += 2;
+	} while (nr < maxchild);
+}
+
+static void uhci_interrupt_notify(struct uhci *uhci)
+{
+	struct list_head *head = &uhci->interrupt_list;
+	struct list_head *tmp;
+
+	spin_lock(&irqlist_lock);
+	tmp = head->next;
+	while (tmp != head) {
+		struct uhci_td *td = list_entry(tmp, struct uhci_td, irq_list);
+		struct list_head *next;
+
+		next = tmp->next;
+
+		if (!(td->status & (1 << 23))) {	/* No longer active? */
+			/* remove from IRQ list */
+			__list_del(tmp->prev, next);
+			INIT_LIST_HEAD(tmp);
+			if (td->completed(td->status, bus_to_virt(td->buffer), td->dev_id)) {
+				struct uhci_qh *interrupt_qh = td->qh;
+
+				list_add(&td->irq_list, &uhci->interrupt_list);
+				td->info ^= 1 << 19; /* toggle between data0 and data1 */
+				td->status = (td->status & 0x2f000000) | (1 << 23) | (1 << 24);	/* active */
+
+				/* Remove then readd? Is that necessary */
+				uhci_remove_td(td);
+				uhci_insert_td_in_qh(interrupt_qh, td);
+			}
+			/* If completed wants to not reactivate, then it's */
+			/* responsible for free'ing the TD's and QH's */
+			/* or another function (such as run_control) */
+		}
+		tmp = next;
+	}
+	spin_unlock(&irqlist_lock);
+}
+
+/*
+ * Check port status - Connect Status Change - for
+ * each of the attached ports (defaults to two ports,
+ * but at least in theory there can be more of them).
+ *
+ * Wake up the configurator if something happened, we
+ * can't really do much at interrupt time.
+ */
+static void uhci_root_hub_events(struct uhci *uhci, unsigned int io_addr)
+{
+	if (waitqueue_active(&uhci_configure)) {
+		int ports = uhci->root_hub->usb->maxchild;
+		io_addr += USBPORTSC1;
+		do {
+			if (inw(io_addr) & USBPORTSC_CSC) {
+				wake_up(&uhci_configure);
+				return;
+			}
+			io_addr += 2;
+		} while (--ports > 0);
+	}
+}
+
+static void uhci_interrupt(int irq, void *__uhci, struct pt_regs *regs)
+{
+	struct uhci *uhci = __uhci;
+	unsigned int io_addr = uhci->io_addr;
+	unsigned short status;
+
+	/*
+	 * Read the interrupt status, and write it back to clear the interrupt cause
+	 */
+	status = inw(io_addr + USBSTS);
+	outw(status, io_addr + USBSTS);
+
+	/* Walk the list of pending TD's to see which ones completed.. */
+	uhci_interrupt_notify(uhci);
+
+	/* Check if there are any events on the root hub.. */
+	uhci_root_hub_events(uhci, io_addr);
+}
+
+/*
+ * We init one packet, and mark it just IOC and _not_
+ * active. Which will result in no actual USB traffic,
+ * but _will_ result in an interrupt every second.
+ *
+ * Which is exactly what we want.
+ */
+static void uhci_init_ticktd(struct uhci *uhci)
+{
+	struct uhci_device *dev = uhci->root_hub;
+	struct uhci_td *td = uhci_td_allocate(dev);
+
+	td->link = 1;
+	td->status = (1 << 24);					/* interrupt on completion */
+	td->info = (15 << 21) | 0x7f69;				/* (ignored) input packet, 16 bytes, device 127 */
+	td->buffer = 0;
+	td->qh = NULL;
+
+	uhci->fl->frame[0] = virt_to_bus(td);
+}
+
+static void reset_hc(struct uhci *uhci)
+{
+	unsigned int io_addr = uhci->io_addr;
+
+	/* Global reset for 50ms */
+	outw(USBCMD_GRESET, io_addr+USBCMD);
+	wait_ms(50);
+	outw(0, io_addr+USBCMD);
+	wait_ms(10);
+}
+
+static void start_hc(struct uhci *uhci)
+{
+	unsigned int io_addr = uhci->io_addr;
+	int timeout = 1000;
+
+	uhci_init_ticktd(uhci);
+
+	/*
+	 * Reset the HC - this will force us to get a
+	 * new notification of any already connected
+	 * ports due to the virtual disconnect that it
+	 * implies.
+	 */
+	outw(USBCMD_HCRESET, io_addr + USBCMD);
+	while (inw(io_addr + USBCMD) & USBCMD_HCRESET) {
+		if (!--timeout) {
+			printk("USBCMD_HCRESET timed out!\n");
+			break;
+		}
+	}
+
+	outw(USBINTR_TIMEOUT | USBINTR_RESUME | USBINTR_IOC | USBINTR_SP, io_addr + USBINTR);
+	outw(0, io_addr + USBFRNUM);
+	outl(virt_to_bus(uhci->fl), io_addr + USBFLBASEADD);
+
+	/* Run and mark it configured with a 64-byte max packet */
+	outw(USBCMD_RS | USBCMD_CF, io_addr + USBCMD);
+}
+
+/*
+ * Allocate a frame list, and four regular queues.
+ *
+ * The hardware doesn't really know any difference
+ * in the queues, but the order does matter for the
+ * protocols higher up. The order is:
+ *
+ *  - any isochronous events handled before any
+ *    of the queues. We don't do that here, because
+ *    we'll create the actual TD entries on demand.
+ *  - The first queue is the "interrupt queue".
+ *  - The second queue is the "control queue".
+ *  - The third queue is "bulk data".
+ *
+ * We could certainly have multiple queues of the same
+ * type, and maybe we should. We could have per-device
+ * queues, for example. We begin small.
+ */
+static struct uhci *alloc_uhci(unsigned int io_addr)
+{
+	int i;
+	struct uhci *uhci;
+	struct usb_bus *bus;
+	struct uhci_device *dev;
+	struct usb_device *usb;
+
+	uhci = kmalloc(sizeof(*uhci), GFP_KERNEL);
+	if (!uhci)
+		return NULL;
+
+	memset(uhci, 0, sizeof(*uhci));
+
+	uhci->irq = -1;
+	uhci->io_addr = io_addr;
+	INIT_LIST_HEAD(&uhci->interrupt_list);
+
+	/* We need exactly one page (per UHCI specs), how convenient */
+	uhci->fl = (void *)__get_free_page(GFP_KERNEL);
+
+	bus = kmalloc(sizeof(*bus), GFP_KERNEL);
+	if (!bus)
+		return NULL;
+
+	memset(bus, 0, sizeof(*bus));
+
+	uhci->bus = bus;
+	bus->hcpriv = uhci;
+	bus->op = &uhci_device_operations;
+
+	/*
+	 * We allocate a 8kB area for the UHCI hub. The area
+	 * is described by the uhci_device structure, and basically
+	 * contains everything needed for normal operation.
+	 *
+	 * The first page is the actual device descriptor for the
+	 * hub.
+	 *
+	 * The second page is used for the frame list.
+	 */
+	usb = uhci_usb_allocate(NULL);
+	if (!usb)
+		return NULL;
+
+	dev = uhci->root_hub = usb_to_uhci(usb);
+
+	usb->bus = bus;
+
+	/* Initialize the root hub */
+	/* UHCI specs says devices must have 2 ports, but goes on to say */
+	/* they may have more but give no way to determine how many they */
+	/* have, so default to 2 */
+	usb->maxchild = 2;
+	usb_init_root_hub(usb);
+
+	/*
+	 * Initialize the queues. They all start out empty,
+	 * linked to each other in the proper order.
+	 */
+	for (i = 1 ; i < 9; i++) {
+		dev->qh[i].link = 2 | virt_to_bus(&dev->skel_control_qh);
+		dev->qh[i].element = 1;
+	}
+	
+	dev->skel_control_qh.link = 2 | virt_to_bus(&dev->skel_bulk0_qh);
+	dev->skel_control_qh.element = 1;
+
+	dev->skel_bulk0_qh.link = 2 | virt_to_bus(&dev->skel_bulk1_qh);
+	dev->skel_bulk0_qh.element = 1;
+
+	dev->skel_bulk1_qh.link = 2 | virt_to_bus(&dev->skel_bulk2_qh);
+	dev->skel_bulk1_qh.element = 1;
+
+	dev->skel_bulk2_qh.link = 2 | virt_to_bus(&dev->skel_bulk3_qh);
+	dev->skel_bulk2_qh.element = 1;
+
+	dev->skel_bulk3_qh.link = 1;
+	dev->skel_bulk3_qh.element = 1;
+
+	/*
+	 * Fill the frame list: make all entries point to
+	 * the proper interrupt queue.
+	 *
+	 * This is probably silly, but it's a simple way to
+	 * scatter the interrupt queues in a way that gives
+	 * us a reasonable dynamic range for irq latencies.
+	 */
+	for (i = 0; i < 1024; i++) {
+		struct uhci_qh * irq = &dev->skel_int2_qh;
+		if (i & 1) {
+			irq++;
+			if (i & 2) {
+				irq++;
+				if (i & 4) { 
+					irq++;
+					if (i & 8) { 
+						irq++;
+						if (i & 16) {
+							irq++;
+							if (i & 32) {
+								irq++;
+								if (i & 64) {
+									irq++;
+								}
+							}
+						}
+					}
+				}
+			}
+		}
+		uhci->fl->frame[i] =  2 | virt_to_bus(irq);
+	}
+
+	return uhci;
+}
+
+
+/*
+ * De-allocate all resources..
+ */
+static void release_uhci(struct uhci *uhci)
+{
+	if (uhci->irq >= 0) {
+		free_irq(uhci->irq, uhci);
+		uhci->irq = -1;
+	}
+
+#if 0
+	if (uhci->root_hub) {
+		uhci_usb_deallocate(uhci_to_usb(uhci->root_hub));
+		uhci->root_hub = NULL;
+	}
+#endif
+
+	if (uhci->fl) {
+		free_page((unsigned long)uhci->fl);
+		uhci->fl = NULL;
+	}
+
+	kfree(uhci->bus);
+	kfree(uhci);
+}
+
+static int uhci_control_thread(void * __uhci)
+{
+	struct uhci *uhci = (struct uhci *)__uhci;
+
+	lock_kernel();
+	request_region(uhci->io_addr, 32, "usb-uhci");
+
+	/*
+	 * This thread doesn't need any user-level access,
+	 * so get rid of all our resources..
+	 */
+	printk("uhci_control_thread at %p\n", &uhci_control_thread);
+	exit_mm(current);
+	exit_files(current);
+	exit_fs(current);
+
+	strcpy(current->comm, "uhci-control");
+
+	/*
+	 * Ok, all systems are go..
+	 */
+	start_hc(uhci);
+	for(;;) {
+		siginfo_t info;
+		int unsigned long signr;
+
+		interruptible_sleep_on(&uhci_configure);
+#ifdef CONFIG_APM
+		if (apm_resume) {
+			apm_resume = 0;
+			start_hc(uhci);
+			continue;
+		}
+#endif
+		uhci_check_configuration(uhci);
+
+		if(signal_pending(current)) {
+			/* sending SIGUSR1 makes us print out some info */
+			spin_lock_irq(&current->sigmask_lock);
+			signr = dequeue_signal(&current->blocked, &info);
+			spin_unlock_irq(&current->sigmask_lock);
+
+			if(signr == SIGUSR1) {
+				printk("UHCI queue dump:\n");
+				show_queues(uhci);
+			} else {
+				break;
+			}
+		}
+	}
+
+#if 0
+	if(uhci->root_hub)
+		for(i = 0; i < uhci->root_hub->usb->maxchild; i++)
+			usb_disconnect(uhci->root_hub->usb->children + i);
+#endif
+
+	reset_hc(uhci);
+	release_region(uhci->io_addr, 32);
+
+	release_uhci(uhci);
+	MOD_DEC_USE_COUNT;
+
+	printk("uhci_control_thread exiting\n");
+
+	return 0;
+}	
+
+/*
+ * If we've successfully found a UHCI, now is the time to increment the
+ * module usage count, start the control thread, and return success..
+ */
+static int found_uhci(int irq, unsigned int io_addr)
+{
+	int retval;
+	struct uhci *uhci;
+
+	uhci = alloc_uhci(io_addr);
+	if (!uhci)
+		return -ENOMEM;
+
+	reset_hc(uhci);
+
+	retval = -EBUSY;
+	if (request_irq(irq, uhci_interrupt, SA_SHIRQ, "usb", uhci) == 0) {
+		int pid;
+
+		MOD_INC_USE_COUNT;
+		uhci->irq = irq;
+		pid = kernel_thread(uhci_control_thread, uhci, CLONE_FS | CLONE_FILES | CLONE_SIGHAND);
+		if (pid >= 0)
+			return 0;
+
+		MOD_DEC_USE_COUNT;
+		retval = pid;
+	}
+	release_uhci(uhci);
+	return retval;
+}
+
+static int start_uhci(struct pci_dev *dev)
+{
+	int i;
+
+	/* Search for the IO base address.. */
+	for (i = 0; i < 6; i++) {
+		unsigned int io_addr = dev->base_address[i];
+
+		/* IO address? */
+		if (!(io_addr & 1))
+			continue;
+
+		io_addr &= PCI_BASE_ADDRESS_IO_MASK;
+
+		/* Is it already in use? */
+		if (check_region(io_addr, 32))
+			break;
+
+		return found_uhci(dev->irq, io_addr);
+	}
+	return -1;
+}
+
+#ifdef CONFIG_APM
+static int handle_apm_event(apm_event_t event)
+{
+	static int down = 0;
+
+	switch (event) {
+	case APM_SYS_SUSPEND:
+	case APM_USER_SUSPEND:
+		if (down) {
+			printk(KERN_DEBUG "uhci: received extra suspend event\n");
+			break;
+		}
+		down = 1;
+		break;
+	case APM_NORMAL_RESUME:
+	case APM_CRITICAL_RESUME:
+		if (!down) {
+			printk(KERN_DEBUG "uhci: received bogus resume event\n");
+			break;
+		}
+		down = 0;
+		if (waitqueue_active(&uhci_configure)) {
+			apm_resume = 1;
+			wake_up(&uhci_configure);
+		}
+		break;
+	}
+	return 0;
+}
+#endif
+
+#ifdef MODULE
+
+void cleanup_module(void)
+{
+#ifdef CONFIG_APM
+	apm_unregister_callback(&handle_apm_event);
+#endif
+}
+
+#define uhci_init init_module
+
+#endif
+
+int uhci_init(void)
+{
+	int retval;
+	struct pci_dev *dev = NULL;
+	u8 type;
+
+	retval = -ENODEV;
+	for (;;) {
+		dev = pci_find_class(PCI_CLASS_SERIAL_USB<<8, dev);
+		if (!dev)
+			break;
+		/* Is it UHCI */
+		pci_read_config_byte(dev, PCI_CLASS_PROG, &type);
+		if(type != 0)
+			continue;
+		/* Ok set it up */
+		retval = start_uhci(dev);
+		if (retval < 0)
+			continue;
+
+#ifdef CONFIG_USB_MOUSE
+		usb_mouse_init();
+#endif
+#ifdef CONFIG_USB_KBD		
+		usb_kbd_init();
+#endif		
+		hub_init();
+#ifdef CONFIG_USB_AUDIO		
+		usb_audio_init();
+#endif		
+#ifdef CONFIG_APM
+		apm_register_callback(&handle_apm_event);
+#endif
+
+		return 0;
+	}
+	return retval;
+}
FUNET's LINUX-ADM group, linux-adm@nic.funet.fi
TCL-scripts by Sam Shen (who was at: slshen@lbl.gov)