hub.c

linux core 函数例程

/*
 * USB hub driver.
 *
 * (C) Copyright 1999 Linus Torvalds
 * (C) Copyright 1999 Johannes Erdfelt
 * (C) Copyright 1999 Gregory P. Smith
 * (C) Copyright 2001 Brad Hards ([e-mail])
 *
 */

#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/completion.h>
#include <linux/sched.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/smp_lock.h>
#include <linux/ioctl.h>
#ifdef CONFIG_USB_DEBUG
	#define DEBUG
#else
	#undef DEBUG
#endif
#include <linux/usb.h>
#include <linux/usbdevice_fs.h>
#include <linux/suspend.h>

#include <asm/semaphore.h>
#include <asm/uaccess.h>
#include <asm/byteorder.h>

#include "hcd.h"
#include "hub.h"

/* Wakes up khubd */
static spinlock_t hub_event_lock = SPIN_LOCK_UNLOCKED;
static DECLARE_MUTEX(usb_address0_sem);

static LIST_HEAD(hub_event_list);	/* List of hubs needing servicing */
static LIST_HEAD(hub_list);		/* List of all hubs (for cleanup) */

static DECLARE_WAIT_QUEUE_HEAD(khubd_wait);
static int khubd_pid = 0;			/* PID of khubd */
static DECLARE_COMPLETION(khubd_exited);

#ifdef	DEBUG
static inline char *portspeed (int portstatus)
{
	if (portstatus & (1 << USB_PORT_FEAT_HIGHSPEED))
    		return "480 Mb/s";
	else if (portstatus & (1 << USB_PORT_FEAT_LOWSPEED))
		return "1.5 Mb/s";
	else
		return "12 Mb/s";
}
#endif

/* USB 2.0 spec Section 11.24.4.5 */
static int usb_get_hub_descriptor(struct usb_device *dev, void *data, int size)
{
	return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
		USB_REQ_GET_DESCRIPTOR, USB_DIR_IN | USB_RT_HUB,
		USB_DT_HUB << 8, 0, data, size, HZ);
}

/*
 * USB 2.0 spec Section 11.24.2.1
 */
static int usb_clear_hub_feature(struct usb_device *dev, int feature)
{
	return usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
		USB_REQ_CLEAR_FEATURE, USB_RT_HUB, feature, 0, NULL, 0, HZ);
}

/*
 * USB 2.0 spec Section 11.24.2.2
 * BUG: doesn't handle port indicator selector in high byte of wIndex
 */
static int usb_clear_port_feature(struct usb_device *dev, int port, int feature)
{
	return usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
		USB_REQ_CLEAR_FEATURE, USB_RT_PORT, feature, port, NULL, 0, HZ);
}

/*
 * USB 2.0 spec Section 11.24.2.13
 * BUG: doesn't handle port indicator selector in high byte of wIndex
 */
static int usb_set_port_feature(struct usb_device *dev, int port, int feature)
{
	return usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
		USB_REQ_SET_FEATURE, USB_RT_PORT, feature, port, NULL, 0, HZ);
}

/*
 * USB 2.0 spec Section 11.24.2.6
 */
static int usb_get_hub_status(struct usb_device *dev, void *data)
{
	return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
		USB_REQ_GET_STATUS, USB_DIR_IN | USB_RT_HUB, 0, 0,
		data, sizeof(struct usb_hub_status), HZ);
}

/*
 * USB 2.0 spec Section 11.24.2.7
 */
static int usb_get_port_status(struct usb_device *dev, int port, void *data)
{
	return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
		USB_REQ_GET_STATUS, USB_DIR_IN | USB_RT_PORT, 0, port,
		data, sizeof(struct usb_hub_status), HZ);
}

/* completion function, fires on port status changes and various faults */
static void hub_irq(struct urb *urb)
{
	struct usb_hub *hub = (struct usb_hub *)urb->context;
	unsigned long flags;

	switch (urb->status) {
	case -ENOENT:		/* synchronous unlink */
	case -ECONNRESET:	/* async unlink */
	case -ESHUTDOWN:	/* hardware going away */
		return;

	default:		/* presumably an error */
		/* Cause a hub reset after 10 consecutive errors */
		dbg("hub '%s' status %d for interrupt transfer",
			urb->dev->devpath, urb->status);
		if ((++hub->nerrors < 10) || hub->error)
			return;
		hub->error = urb->status;
		/* FALL THROUGH */
	
	/* let khubd handle things */
	case 0:			/* we got data:  port status changed */
		break;
	}

	hub->nerrors = 0;

	/* Something happened, let khubd figure it out */
	spin_lock_irqsave(&hub_event_lock, flags);
	if (list_empty(&hub->event_list)) {
		list_add(&hub->event_list, &hub_event_list);
		wake_up(&khubd_wait);
	}
	spin_unlock_irqrestore(&hub_event_lock, flags);
}

/* USB 2.0 spec Section 11.24.2.3 */
static inline int
hub_clear_tt_buffer (struct usb_device *hub, u16 devinfo, u16 tt)
{
	return usb_control_msg (hub, usb_rcvctrlpipe (hub, 0),
		HUB_CLEAR_TT_BUFFER, USB_DIR_IN | USB_RECIP_OTHER,
		devinfo, tt, 0, 0, HZ);
}

/*
 * enumeration blocks khubd for a long time. we use keventd instead, since
 * long blocking there is the exception, not the rule.  accordingly, HCDs
 * talking to TTs must queue control transfers (not just bulk and iso), so
 * both can talk to the same hub concurrently.
 */
static void hub_tt_kevent (void *arg)
{
	struct usb_hub		*hub = arg;
	unsigned long		flags;

	spin_lock_irqsave (&hub->tt.lock, flags);
	while (!list_empty (&hub->tt.clear_list)) {
		struct list_head	*temp;
		struct usb_tt_clear	*clear;
		int			status;

		temp = hub->tt.clear_list.next;
		clear = list_entry (temp, struct usb_tt_clear, clear_list);
		list_del (&clear->clear_list);

		/* drop lock so HCD can concurrently report other TT errors */
		spin_unlock_irqrestore (&hub->tt.lock, flags);
		status = hub_clear_tt_buffer (hub->dev,
				clear->devinfo, clear->tt);
		spin_lock_irqsave (&hub->tt.lock, flags);

		if (status)
			err ("usb-%s-%s clear tt %d (%04x) error %d",
				hub->dev->bus->bus_name, hub->dev->devpath,
				clear->tt, clear->devinfo, status);
		kfree (clear);
	}
	spin_unlock_irqrestore (&hub->tt.lock, flags);
}

/**
 * usb_hub_tt_clear_buffer - clear control/bulk TT state in high speed hub
 * @dev: the device whose split transaction failed
 * @pipe: identifies the endpoint of the failed transaction
 *
 * High speed HCDs use this to tell the hub driver that some split control or
 * bulk transaction failed in a way that requires clearing internal state of
 * a transaction translator.  This is normally detected (and reported) from
 * interrupt context.
 *
 * It may not be possible for that hub to handle additional full (or low)
 * speed transactions until that state is fully cleared out.
 */
void usb_hub_tt_clear_buffer (struct usb_device *dev, int pipe)
{
	struct usb_tt		*tt = dev->tt;
	unsigned long		flags;
	struct usb_tt_clear	*clear;

	/* we've got to cope with an arbitrary number of pending TT clears,
	 * since each TT has "at least two" buffers that can need it (and
	 * there can be many TTs per hub).  even if they're uncommon.
	 */
	if ((clear = kmalloc (sizeof *clear, SLAB_ATOMIC)) == 0) {
		err ("can't save CLEAR_TT_BUFFER state for hub at usb-%s-%s",
			dev->bus->bus_name, tt->hub->devpath);
		/* FIXME recover somehow ... RESET_TT? */
		return;
	}

	/* info that CLEAR_TT_BUFFER needs */
	clear->tt = tt->multi ? dev->ttport : 1;
	clear->devinfo = usb_pipeendpoint (pipe);
	clear->devinfo |= dev->devnum << 4;
	clear->devinfo |= usb_pipecontrol (pipe)
			? (USB_ENDPOINT_XFER_CONTROL << 11)
			: (USB_ENDPOINT_XFER_BULK << 11);
	if (usb_pipein (pipe))
		clear->devinfo |= 1 << 15;
	
	/* tell keventd to clear state for this TT */
	spin_lock_irqsave (&tt->lock, flags);
	list_add_tail (&clear->clear_list, &tt->clear_list);
	schedule_task (&tt->kevent);
	spin_unlock_irqrestore (&tt->lock, flags);
}

static void usb_hub_power_on(struct usb_hub *hub)
{
	int i;

	/* Enable power to the ports */
	dbg("enabling power on all ports");
	for (i = 0; i < hub->descriptor->bNbrPorts; i++)
		usb_set_port_feature(hub->dev, i + 1, USB_PORT_FEAT_POWER);

	/* Wait for power to be enabled */
	wait_ms(hub->descriptor->bPwrOn2PwrGood * 2);
}

static int usb_hub_configure(struct usb_hub *hub,
	struct usb_endpoint_descriptor *endpoint)
{
	struct usb_device *dev = hub->dev;
	struct usb_hub_status hubstatus;
	char portstr[USB_MAXCHILDREN + 1];
	unsigned int pipe;
	int i, maxp, ret;

	hub->descriptor = kmalloc(sizeof(*hub->descriptor), GFP_KERNEL);
	if (!hub->descriptor) {
		err("Unable to kmalloc %Zd bytes for hub descriptor",
			sizeof(*hub->descriptor));
		return -1;
	}

	/* Request the entire hub descriptor.
	 * hub->descriptor can handle USB_MAXCHILDREN ports,
	 * but the hub can/will return fewer bytes here.
	 */
	ret = usb_get_hub_descriptor(dev, hub->descriptor,
			sizeof(*hub->descriptor));
	if (ret < 0) {
		err("Unable to get hub descriptor (err = %d)", ret);
		kfree(hub->descriptor);
		return -1;
	} else if (hub->descriptor->bNbrPorts > USB_MAXCHILDREN) {
		err("Hub is too big! %d children", hub->descriptor->bNbrPorts);
		kfree(hub->descriptor);
		return -1;
	}

	dev->maxchild = hub->descriptor->bNbrPorts;
	info("%d port%s detected", dev->maxchild,
		(dev->maxchild == 1) ? "" : "s");

	le16_to_cpus(&hub->descriptor->wHubCharacteristics);

	if (hub->descriptor->wHubCharacteristics & HUB_CHAR_COMPOUND)
		dbg("part of a compound device");
	else
		dbg("standalone hub");

	switch (hub->descriptor->wHubCharacteristics & HUB_CHAR_LPSM) {
		case 0x00:
			dbg("ganged power switching");
			break;
		case 0x01:
			dbg("individual port power switching");
			break;
		case 0x02:
		case 0x03:
			dbg("unknown reserved power switching mode");
			break;
	}

	switch (hub->descriptor->wHubCharacteristics & HUB_CHAR_OCPM) {
		case 0x00:
			dbg("global over-current protection");
			break;
		case 0x08:
			dbg("individual port over-current protection");
			break;
		case 0x10:
		case 0x18:
			dbg("no over-current protection");
                        break;
	}

	spin_lock_init (&hub->tt.lock);
	INIT_LIST_HEAD (&hub->tt.clear_list);
	INIT_TQUEUE (&hub->tt.kevent, hub_tt_kevent, hub);
	switch (dev->descriptor.bDeviceProtocol) {
		case 0:
			break;
		case 1:
			dbg("Single TT");
			hub->tt.hub = dev;
			break;
		case 2:
			dbg("TT per port");
			hub->tt.hub = dev;
			hub->tt.multi = 1;
			break;
		default:
			dbg("Unrecognized hub protocol %d",
				dev->descriptor.bDeviceProtocol);
			break;
	}

	switch (hub->descriptor->wHubCharacteristics & HUB_CHAR_TTTT) {
		case 0x00:
			if (dev->descriptor.bDeviceProtocol != 0)
				dbg("TT requires at most 8 FS bit times");
			break;
		case 0x20:
			dbg("TT requires at most 16 FS bit times");
			break;
		case 0x40:
			dbg("TT requires at most 24 FS bit times");
			break;
		case 0x60:
			dbg("TT requires at most 32 FS bit times");
			break;
	}

	dbg("Port indicators are %s supported", 
	    (hub->descriptor->wHubCharacteristics & HUB_CHAR_PORTIND)
	    	? "" : "not");

	dbg("power on to power good time: %dms",
		hub->descriptor->bPwrOn2PwrGood * 2);
	dbg("hub controller current requirement: %dmA",
		hub->descriptor->bHubContrCurrent);

	for (i = 0; i < dev->maxchild; i++)
		portstr[i] = hub->descriptor->DeviceRemovable
			    [((i + 1) / 8)] & (1 << ((i + 1) % 8))
			? 'F' : 'R';
	portstr[dev->maxchild] = 0;

	dbg("port removable status: %s", portstr);

	ret = usb_get_hub_status(dev, &hubstatus);
	if (ret < 0) {
		err("Unable to get hub status (err = %d)", ret);
		kfree(hub->descriptor);
		return -1;
	}

	le16_to_cpus(&hubstatus.wHubStatus);

	dbg("local power source is %s",
		(hubstatus.wHubStatus & HUB_STATUS_LOCAL_POWER)
		? "lost (inactive)" : "good");

	dbg("%sover-current condition exists",
		(hubstatus.wHubStatus & HUB_STATUS_OVERCURRENT) ? "" : "no ");

	/* Start the interrupt endpoint */
	pipe = usb_rcvintpipe(dev, endpoint->bEndpointAddress);
	maxp = usb_maxpacket(dev, pipe, usb_pipeout(pipe));

	if (maxp > sizeof(hub->buffer))
		maxp = sizeof(hub->buffer);

	hub->urb = usb_alloc_urb(0, GFP_KERNEL);
	if (!hub->urb) {
		err("couldn't allocate interrupt urb");
		kfree(hub->descriptor);
		return -1;
	}

	FILL_INT_URB(hub->urb, dev, pipe, hub->buffer, maxp, hub_irq,
		hub, endpoint->bInterval);
	ret = usb_submit_urb(hub->urb, GFP_KERNEL);
	if (ret) {
		err("usb_submit_urb failed (%d)", ret);
		kfree(hub->descriptor);
		return -1;
	}
		
	/* Wake up khubd */
	wake_up(&khubd_wait);

	usb_hub_power_on(hub);