uhci.c

超小usb协议栈

	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 init_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

int init_module(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 = init_uhci(dev);
		if (retval < 0)
			continue;

		usb_mouse_init();
		usb_kbd_init();
		hub_init();
#ifdef CONFIG_APM
		apm_register_callback(&handle_apm_event);
#endif

		return 0;
	}
	return retval;
}

void cleanup_module(void)
{
#ifdef CONFIG_APM
	apm_unregister_callback(&handle_apm_event);
#endif
}