hid.c

讲述linux的初始化过程

				&& field->usage[value[n] - min].hid				/* nonzero usage */
				&& search(field->value, value[n], count))
					hid_process_event(&dev->input, &dev->quirks,
						field, &field->usage[value[n] - min], 1);
		}
	}

	memcpy(field->value, value, count * sizeof(__s32));
}

/*
 * Interrupt input handler - analyse a received report.
 */

static void hid_irq(struct urb *urb)
{
	struct hid_device *device = urb->context;
	struct hid_report_enum *report_enum = device->report_enum + HID_INPUT_REPORT;
	struct hid_report *report;
	__u8 *data = urb->transfer_buffer;
	int len = urb->actual_length;
	int n;

	if (urb->status) {
		dbg("nonzero status in irq %d", urb->status);
		return;
	}

	if (!len) {
		dbg("empty report");
		return;
	}

#ifdef DEBUG_DATA
	printk(KERN_DEBUG __FILE__ ": report (size %u) (%snumbered) = ", len, report_enum->numbered ? "" : "un");
	for (n = 0; n < len; n++)
		printk(" %02x", data[n]);
	printk("\n");
#endif

	n = 0;				/* Normally report number is 0 */

	if (report_enum->numbered) {	/* Device uses numbered reports, data[0] is report number */
		n = *data++;
		len--;
	} 

	if (!(report = report_enum->report_id_hash[n])) {
		dbg("undefined report_id %d received", n);
#ifdef DEBUG
			printk(KERN_DEBUG __FILE__ ": report (size %u) = ", len);
			for (n = 0; n < len; n++)
				printk(" %02x", data[n]);
			printk("\n");
#endif
	
		return;
	}

	if (len < ((report->size - 1) >> 3) + 1) {
		dbg("report %d is too short, (%d < %d)", report->id, len, ((report->size - 1) >> 3) + 1);
		return;
	}

	for (n = 0; n < report->maxfield; n++)
		hid_input_field(device, report->field[n], data);

	return;
}

/*
 * hid_read_report() s intended to read the hid devices values even
 * before the input device is registered, so that the userland interface
 * modules start with real values. This is especially important for joydev.c
 * automagic calibration. Doesn't work yet, though. Don't know why, the control
 * request just times out on most devices I have and returns nonsense on others.
 */

static void hid_read_report(struct hid_device *hid, struct hid_report *report)
{
#if 0
	int rlen = ((report->size - 1) >> 3) + 1;
	char rdata[rlen];
	struct urb urb;
	int read, j;

	memset(&urb, 0, sizeof(struct urb));
	memset(rdata, 0, rlen);

	urb.transfer_buffer = rdata;
	urb.actual_length = rlen;
	urb.context = hid;

	dbg("getting report type %d id %d len %d", report->type + 1, report->id, rlen);

	if ((read = usb_get_report(hid->dev, hid->ifnum, report->type + 1, report->id, rdata, rlen)) != rlen) {
		dbg("reading report failed rlen %d read %d", rlen, read);
#ifdef DEBUG
		printk(KERN_DEBUG __FILE__ ": report = ");
		for (j = 0; j < rlen; j++) printk(" %02x", rdata[j]);
		printk("\n");
#endif
		return;
	}

	hid_irq(&urb);
#endif
}

/*
 * Output the field into the report.
 */

static void hid_output_field(struct hid_field *field, __u8 *data)
{
	unsigned count = field->report_count;
	unsigned offset = field->report_offset;
	unsigned size = field->report_size;
	unsigned n;
   
	for (n = 0; n < count; n++) {
		if (field->logical_minimum < 0)	/* signed values */
			implement(data, offset + n * size, size, s32ton(field->value[n], size));
		 else				/* unsigned values */
			implement(data, offset + n * size, size, field->value[n]);
       	}
}

/*
 * Create a report.
 */

void hid_output_report(struct hid_report *report, __u8 *data)
{
	unsigned n;
	for (n = 0; n < report->maxfield; n++)
		hid_output_field(report->field[n], data);
};

/*
 * Set a field value. The report this field belongs to has to be
 * created and transfered to the device, to set this value in the
 * device.
 */

int hid_set_field(struct hid_field *field, unsigned offset, __s32 value)
{
	unsigned size = field->report_size;

	hid_dump_input(field->usage + offset, value);
	
	if (offset >= field->report_count) {
		dbg("offset exceeds report_count");
		return -1;
	}
	if (field->logical_minimum < 0) {
		if (value != snto32(s32ton(value, size), size)) {
			dbg("value %d is out of range", value);
			return -1;
		}
	}
	if (   (value > field->logical_maximum)
	    || (value < field->logical_minimum)) {
		dbg("value %d is invalid", value);
		return -1;
	}
	field->value[offset] = value;
	return 0;
}

static int hid_find_field(struct hid_device *hid, unsigned int type, unsigned int code, struct hid_field **field)
{
	struct hid_report_enum *report_enum = hid->report_enum + HID_OUTPUT_REPORT;
	struct list_head *list = report_enum->report_list.next;
	int i, j;

	while (list != &report_enum->report_list) {
		struct hid_report *report = (struct hid_report *) list;
		list = list->next;
		for (i = 0; i < report->maxfield; i++) {
			*field = report->field[i];
			for (j = 0; j < (*field)->maxusage; j++)
				if ((*field)->usage[j].type == type && (*field)->usage[j].code == code)
					return j;
		}
	}
	return -1;
}

static int hid_submit_out(struct hid_device *hid)
{
	hid->urbout.transfer_buffer_length = hid->out[hid->outtail].dr.length;
	hid->urbout.transfer_buffer = hid->out[hid->outtail].buffer;
	hid->urbout.setup_packet = (void *) &(hid->out[hid->outtail].dr);
	hid->urbout.dev = hid->dev;

	if (usb_submit_urb(&hid->urbout)) {
		err("usb_submit_urb(out) failed");
		return -1;
	}

	return 0;
}

static void hid_ctrl(struct urb *urb)
{
	struct hid_device *hid = urb->context;

        if (urb->status)
		warn("ctrl urb status %d received", urb->status);
	
	hid->outtail = (hid->outtail + 1) & (HID_CONTROL_FIFO_SIZE - 1);

	if (hid->outhead != hid->outtail)
		hid_submit_out(hid);
}       

static int hid_event(struct input_dev *dev, unsigned int type, unsigned int code, int value)
{
	struct hid_device *hid = dev->private;
	struct hid_field *field = NULL;
	int offset;

	if ((offset = hid_find_field(hid, type, code, &field)) == -1) {
		warn("event field not found");
		return -1;
	}

	hid_set_field(field, offset, value);
	hid_output_report(field->report, hid->out[hid->outhead].buffer);

	hid->out[hid->outhead].dr.value = 0x200 | field->report->id;
	hid->out[hid->outhead].dr.length = ((field->report->size - 1) >> 3) + 1;

	hid->outhead = (hid->outhead + 1) & (HID_CONTROL_FIFO_SIZE - 1);

	if (hid->outhead == hid->outtail)
		hid->outtail = (hid->outtail + 1) & (HID_CONTROL_FIFO_SIZE - 1);

	if (hid->urbout.status != -EINPROGRESS)
		hid_submit_out(hid);

	return 0;
}

static int hid_open(struct input_dev *dev)
{
	struct hid_device *hid = dev->private;

	if (hid->open++)
		return 0;

	hid->urb.dev = hid->dev;

	if (usb_submit_urb(&hid->urb))
		return -EIO;

	return 0;
}

static void hid_close(struct input_dev *dev)
{
	struct hid_device *hid = dev->private;

	if (!--hid->open)
		usb_unlink_urb(&hid->urb);
}

/*
 * Configure the input layer interface
 * Read all reports and initalize the absoulte field values.
 */

static void hid_init_input(struct hid_device *hid)
{
	struct hid_report_enum *report_enum;
	struct list_head *list;
	int i, j, k;

	hid->input.private = hid;
	hid->input.event = hid_event;
	hid->input.open = hid_open;
	hid->input.close = hid_close;

	for (k = HID_INPUT_REPORT; k <= HID_OUTPUT_REPORT; k++) {

		report_enum = hid->report_enum + k;
		list = report_enum->report_list.next;

		while (list != &report_enum->report_list) {

			struct hid_report *report = (struct hid_report *) list;

			list = list->next;

			for (i = 0; i < report->maxfield; i++)
				for (j = 0; j < report->field[i]->maxusage; j++)
					hid_configure_usage(hid, report->field[i], report->field[i]->usage + j);

			if (k == HID_INPUT_REPORT)  {
				usb_set_idle(hid->dev, hid->ifnum, 0, report->id);
				hid_read_report(hid, report);
			}
		}
	}
}

#define USB_VENDOR_ID_WACOM		0x056a
#define USB_DEVICE_ID_WACOM_GRAPHIRE	0x0010
#define USB_DEVICE_ID_WACOM_INTUOS	0x0020

struct hid_blacklist {
	__u16 idVendor;
	__u16 idProduct;
} hid_blacklist[] = {
	{ USB_VENDOR_ID_WACOM, USB_DEVICE_ID_WACOM_GRAPHIRE },
	{ USB_VENDOR_ID_WACOM, USB_DEVICE_ID_WACOM_INTUOS },
	{ USB_VENDOR_ID_WACOM, USB_DEVICE_ID_WACOM_INTUOS + 1},
	{ USB_VENDOR_ID_WACOM, USB_DEVICE_ID_WACOM_INTUOS + 2},
	{ USB_VENDOR_ID_WACOM, USB_DEVICE_ID_WACOM_INTUOS + 3},
	{ USB_VENDOR_ID_WACOM, USB_DEVICE_ID_WACOM_INTUOS + 4},
	{ 0, 0 }
};

static struct hid_device *usb_hid_configure(struct usb_device *dev, int ifnum, char *name)
{
	struct usb_interface_descriptor *interface = dev->actconfig->interface[ifnum].altsetting + 0;
	struct hid_descriptor *hdesc;
	struct hid_device *hid;
	unsigned rsize = 0;
	int n;

	for (n = 0; hid_blacklist[n].idVendor; n++)
		if ((hid_blacklist[n].idVendor == dev->descriptor.idVendor) &&
			(hid_blacklist[n].idProduct == dev->descriptor.idProduct)) return NULL;

	if (usb_get_extra_descriptor(interface, USB_DT_HID, &hdesc)
		&& usb_get_extra_descriptor(&interface->endpoint[0], USB_DT_HID, &hdesc)) {
			dbg("class descriptor not present\n");
			return NULL;
	}

	for (n = 0; n < hdesc->bNumDescriptors; n++)
		if (hdesc->desc[n].bDescriptorType == USB_DT_REPORT)
			rsize = le16_to_cpu(hdesc->desc[n].wDescriptorLength);

	if (!rsize || rsize > HID_MAX_DESCRIPTOR_SIZE) {
		dbg("weird size of report descriptor (%u)", rsize);
		return NULL;
	}

	{
		__u8 rdesc[rsize];

		if ((n = usb_get_class_descriptor(dev, interface->bInterfaceNumber, USB_DT_REPORT, 0, rdesc, rsize)) < 0) {
			dbg("reading report descriptor failed");
			return NULL;
		}

#ifdef DEBUG_DATA
		printk(KERN_DEBUG __FILE__ ": report (size %u, read %d) = ", rsize, n);
		for (n = 0; n < rsize; n++)
			printk(" %02x", (unsigned) rdesc[n]);
		printk("\n");
#endif

		if (!(hid = hid_parse_report(rdesc, rsize))) {
			dbg("parsing report descriptor failed");
			return NULL;
		}
	}

	for (n = 0; n < interface->bNumEndpoints; n++) {

		struct usb_endpoint_descriptor *endpoint = &interface->endpoint[n];
		int pipe, maxp;

		if ((endpoint->bmAttributes & 3) != 3)		/* Not an interrupt endpoint */
			continue;

		if (!(endpoint->bEndpointAddress & 0x80)) 	/* Not an input endpoint */
			continue;

		pipe = usb_rcvintpipe(dev, endpoint->bEndpointAddress);
		maxp = usb_maxpacket(dev, pipe, usb_pipeout(pipe));

		FILL_INT_URB(&hid->urb, dev, pipe, hid->buffer, maxp > 32 ? 32 : maxp, hid_irq, hid, endpoint->bInterval);
	
		break;
	}

	if (n == interface->bNumEndpoints) {
		dbg("couldn't find an input interrupt endpoint");
		hid_free_device(hid);
		return NULL;
	}

	hid->version = hdesc->bcdHID;
	hid->country = hdesc->bCountryCode;
	hid->dev = dev;
	hid->ifnum = interface->bInterfaceNumber;

	for (n = 0; n < HID_CONTROL_FIFO_SIZE; n++) {
		hid->out[n].dr.requesttype = USB_TYPE_CLASS | USB_RECIP_INTERFACE;
		hid->out[n].dr.request = USB_REQ_SET_REPORT;
		hid->out[n].dr.index = hid->ifnum;
	}

	hid->input.name = hid->name;
	hid->input.idbus = BUS_USB;
	hid->input.idvendor = dev->descriptor.idVendor;
	hid->input.idproduct = dev->descriptor.idProduct;
	hid->input.idversion = dev->descriptor.bcdDevice;

	if (strlen(name)) 
		strcpy(hid->name, name);
	else
		sprintf(hid->name, "USB HID %s %04x:%04x",
			((hid->application >= 0x00010000) && (hid->application <= 0x00010008)) ?
			hid_types[hid->application & 0xffff] : "Device",
			hid->input.idvendor, hid->input.idproduct);

	FILL_CONTROL_URB(&hid->urbout, dev, usb_sndctrlpipe(dev, 0),
		(void*) &hid->out[0].dr, hid->out[0].buffer, 1, hid_ctrl, hid);

	if (interface->bInterfaceSubClass == 1)
        	usb_set_protocol(dev, hid->ifnum, 1);

	return hid;
}

static void* hid_probe(struct usb_device *dev, unsigned int ifnum,
		       const struct usb_device_id *id)
{
	struct hid_device *hid;
	char name[128];
	char *buf;

	dbg("HID probe called for ifnum %d", ifnum);

	name[0] = 0;

	if (!(buf = kmalloc(63, GFP_KERNEL)))
		return NULL;

	if (dev->descriptor.iManufacturer &&
		usb_string(dev, dev->descriptor.iManufacturer, buf, 63) > 0)
			strcat(name, buf);
	if (dev->descriptor.iProduct &&
		usb_string(dev, dev->descriptor.iProduct, buf, 63) > 0)
			sprintf(name, "%s %s", name, buf);

	kfree(buf);

	if (!(hid = usb_hid_configure(dev, ifnum, name)))
		return NULL;

	hid_dump_device(hid);

	hid_init_input(hid);
	input_register_device(&hid->input);

	printk(KERN_INFO "input%d: USB HID v%x.%02x %s",
		hid->input.number,
		hid->version >> 8, hid->version & 0xff,
		((hid->application >= 0x00010000) && (hid->application <= 0x00010008)) ?
		hid_types[hid->application & 0xffff] : "Device");

	if (strlen(name))
		printk(" [%s]", name);
	else
		printk(" [%04x:%04x]", hid->input.idvendor, hid->input.idproduct);
	
	printk(" on usb%d:%d.%d\n", dev->bus->busnum, dev->devnum, ifnum);

	return hid;
}

static void hid_disconnect(struct usb_device *dev, void *ptr)
{
	struct hid_device *hid = ptr;

	dbg("cleanup called");
	usb_unlink_urb(&hid->urb);
	input_unregister_device(&hid->input);
	hid_free_device(hid);
}

static struct usb_device_id hid_usb_ids [] = {
    { match_flags: USB_DEVICE_ID_MATCH_INT_CLASS,
      bInterfaceClass: USB_INTERFACE_CLASS_HID},
    { }						/* Terminating entry */
};

MODULE_DEVICE_TABLE (usb, hid_usb_ids);

static struct usb_driver hid_driver = {
	name:		"hid",
	probe:		hid_probe,
	disconnect:	hid_disconnect,
	id_table:	hid_usb_ids,
};

static int __init hid_init(void)
{
	usb_register(&hid_driver);
	return 0;
}

static void __exit hid_exit(void)
{
	usb_deregister(&hid_driver);
}

module_init(hid_init);
module_exit(hid_exit);

MODULE_AUTHOR("Andreas Gal, Vojtech Pavlik <[e-mail]>");
MODULE_DESCRIPTION("USB HID support drivers");