config.c

来自「omap3 linux 2.6 用nocc去除了冗余代码」· C语言 代码 · 共 572 行 · 第 1/2 页

#include <linux/usb.h>
#include <linux/usb/ch9.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <asm/byteorder.h>
#include "usb.h"
#include "hcd.h"

#define USB_MAXALTSETTING		128	/* Hard limit */
#define USB_MAXENDPOINTS		30	/* Hard limit */

#define USB_MAXCONFIG			8	/* Arbitrary limit */


static inline const char *plural(int n)
{
	return (n == 1 ? "" : "s");
}

static int find_next_descriptor(unsigned char *buffer, int size,
    int dt1, int dt2, int *num_skipped)
{
	struct usb_descriptor_header *h;
	int n = 0;
	unsigned char *buffer0 = buffer;

	/* Find the next descriptor of type dt1 or dt2 */
	while (size > 0) {
		h = (struct usb_descriptor_header *) buffer;
		if (h->bDescriptorType == dt1 || h->bDescriptorType == dt2)
			break;
		buffer += h->bLength;
		size -= h->bLength;
		++n;
	}

	/* Store the number of descriptors skipped and return the
	 * number of bytes skipped */
	if (num_skipped)
		*num_skipped = n;
	return buffer - buffer0;
}

static int usb_parse_endpoint(struct device *ddev, int cfgno, int inum,
    int asnum, struct usb_host_interface *ifp, int num_ep,
    unsigned char *buffer, int size)
{
	unsigned char *buffer0 = buffer;
	struct usb_endpoint_descriptor *d;
	struct usb_host_endpoint *endpoint;
	int n, i, j;

	d = (struct usb_endpoint_descriptor *) buffer;
	buffer += d->bLength;
	size -= d->bLength;

	if (d->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE)
		n = USB_DT_ENDPOINT_AUDIO_SIZE;
	else if (d->bLength >= USB_DT_ENDPOINT_SIZE)
		n = USB_DT_ENDPOINT_SIZE;
	else {
		dev_warn(ddev, "config %d interface %d altsetting %d has an "
		    "invalid endpoint descriptor of length %d, skipping\n",
		    cfgno, inum, asnum, d->bLength);
		goto skip_to_next_endpoint_or_interface_descriptor;
	}

	i = d->bEndpointAddress & ~USB_ENDPOINT_DIR_MASK;
	if (i >= 16 || i == 0) {
		dev_warn(ddev, "config %d interface %d altsetting %d has an "
		    "invalid endpoint with address 0x%X, skipping\n",
		    cfgno, inum, asnum, d->bEndpointAddress);
		goto skip_to_next_endpoint_or_interface_descriptor;
	}

	/* Only store as many endpoints as we have room for */
	if (ifp->desc.bNumEndpoints >= num_ep)
		goto skip_to_next_endpoint_or_interface_descriptor;

	endpoint = &ifp->endpoint[ifp->desc.bNumEndpoints];
	++ifp->desc.bNumEndpoints;

	memcpy(&endpoint->desc, d, n);
	INIT_LIST_HEAD(&endpoint->urb_list);

	/* If the bInterval value is outside the legal range,
	 * set it to a default value: 32 ms */
	i = 0;		/* i = min, j = max, n = default */
	j = 255;
	if (usb_endpoint_xfer_int(d)) {
		i = 1;
		switch (to_usb_device(ddev)->speed) {
		case USB_SPEED_HIGH:
			n = 9;		/* 32 ms = 2^(9-1) uframes */
			j = 16;
			break;
		default:		/* USB_SPEED_FULL or _LOW */
			/* For low-speed, 10 ms is the official minimum.
			 * But some "overclocked" devices might want faster
			 * polling so we'll allow it. */
			n = 32;
			break;
		}
	} else if (usb_endpoint_xfer_isoc(d)) {
		i = 1;
		j = 16;
		switch (to_usb_device(ddev)->speed) {
		case USB_SPEED_HIGH:
			n = 9;		/* 32 ms = 2^(9-1) uframes */
			break;
		default:		/* USB_SPEED_FULL */
			n = 6;		/* 32 ms = 2^(6-1) frames */
			break;
		}
	}
	if (d->bInterval < i || d->bInterval > j) {
		dev_warn(ddev, "config %d interface %d altsetting %d "
		    "endpoint 0x%X has an invalid bInterval %d, "
		    "changing to %d\n",
		    cfgno, inum, asnum,
		    d->bEndpointAddress, d->bInterval, n);
		endpoint->desc.bInterval = n;
	}

	/* Skip over any Class Specific or Vendor Specific descriptors;
	 * find the next endpoint or interface descriptor */
	endpoint->extra = buffer;
	i = find_next_descriptor(buffer, size, USB_DT_ENDPOINT,
	    USB_DT_INTERFACE, &n);
	endpoint->extralen = i;
	if (n > 0)
		dev_dbg(ddev, "skipped %d descriptor%s after %s\n",
		    n, plural(n), "endpoint");
	return buffer - buffer0 + i;

skip_to_next_endpoint_or_interface_descriptor:
	i = find_next_descriptor(buffer, size, USB_DT_ENDPOINT,
	    USB_DT_INTERFACE, NULL);
	return buffer - buffer0 + i;
}

void usb_release_interface_cache(struct kref *ref)
{
	struct usb_interface_cache *intfc = ref_to_usb_interface_cache(ref);
	int j;

	for (j = 0; j < intfc->num_altsetting; j++) {
		struct usb_host_interface *alt = &intfc->altsetting[j];

		kfree(alt->endpoint);
		kfree(alt->string);
	}
	kfree(intfc);
}

static int usb_parse_interface(struct device *ddev, int cfgno,
    struct usb_host_config *config, unsigned char *buffer, int size,
    u8 inums[], u8 nalts[])
{
	unsigned char *buffer0 = buffer;
	struct usb_interface_descriptor	*d;
	int inum, asnum;
	struct usb_interface_cache *intfc;
	struct usb_host_interface *alt;
	int i, n;
	int len, retval;
	int num_ep, num_ep_orig;

	d = (struct usb_interface_descriptor *) buffer;
	buffer += d->bLength;
	size -= d->bLength;

	if (d->bLength < USB_DT_INTERFACE_SIZE)
		goto skip_to_next_interface_descriptor;

	/* Which interface entry is this? */
	intfc = NULL;
	inum = d->bInterfaceNumber;
	for (i = 0; i < config->desc.bNumInterfaces; ++i) {
		if (inums[i] == inum) {
			intfc = config->intf_cache[i];
			break;
		}
	}
	if (!intfc || intfc->num_altsetting >= nalts[i])
		goto skip_to_next_interface_descriptor;

	/* Check for duplicate altsetting entries */
	asnum = d->bAlternateSetting;
	for ((i = 0, alt = &intfc->altsetting[0]);
	      i < intfc->num_altsetting;
	     (++i, ++alt)) {
		if (alt->desc.bAlternateSetting == asnum) {
			dev_warn(ddev, "Duplicate descriptor for config %d "
			    "interface %d altsetting %d, skipping\n",
			    cfgno, inum, asnum);
			goto skip_to_next_interface_descriptor;
		}
	}

	++intfc->num_altsetting;
	memcpy(&alt->desc, d, USB_DT_INTERFACE_SIZE);

	/* Skip over any Class Specific or Vendor Specific descriptors;
	 * find the first endpoint or interface descriptor */
	alt->extra = buffer;
	i = find_next_descriptor(buffer, size, USB_DT_ENDPOINT,
	    USB_DT_INTERFACE, &n);
	alt->extralen = i;
	if (n > 0)
		dev_dbg(ddev, "skipped %d descriptor%s after %s\n",
		    n, plural(n), "interface");
	buffer += i;
	size -= i;

	/* Allocate space for the right(?) number of endpoints */
	num_ep = num_ep_orig = alt->desc.bNumEndpoints;
	alt->desc.bNumEndpoints = 0;		// Use as a counter
	if (num_ep > USB_MAXENDPOINTS) {
		dev_warn(ddev, "too many endpoints for config %d interface %d "
		    "altsetting %d: %d, using maximum allowed: %d\n",
		    cfgno, inum, asnum, num_ep, USB_MAXENDPOINTS);
		num_ep = USB_MAXENDPOINTS;
	}

	if (num_ep > 0) {	/* Can't allocate 0 bytes */
		len = sizeof(struct usb_host_endpoint) * num_ep;
		alt->endpoint = kzalloc(len, GFP_KERNEL);
		if (!alt->endpoint)
			return -ENOMEM;
	}

	/* Parse all the endpoint descriptors */
	n = 0;
	while (size > 0) {
		if (((struct usb_descriptor_header *) buffer)->bDescriptorType
		     == USB_DT_INTERFACE)
			break;
		retval = usb_parse_endpoint(ddev, cfgno, inum, asnum, alt,
		    num_ep, buffer, size);
		if (retval < 0)
			return retval;
		++n;

		buffer += retval;
		size -= retval;
	}

	if (n != num_ep_orig)
		dev_warn(ddev, "config %d interface %d altsetting %d has %d "
		    "endpoint descriptor%s, different from the interface "
		    "descriptor's value: %d\n",
		    cfgno, inum, asnum, n, plural(n), num_ep_orig);
	return buffer - buffer0;

skip_to_next_interface_descriptor:
	i = find_next_descriptor(buffer, size, USB_DT_INTERFACE,
	    USB_DT_INTERFACE, NULL);
	return buffer - buffer0 + i;
}

static int usb_parse_configuration(struct device *ddev, int cfgidx,
    struct usb_host_config *config, unsigned char *buffer, int size)
{
	unsigned char *buffer0 = buffer;
	int cfgno;
	int nintf, nintf_orig;
	int i, j, n;
	struct usb_interface_cache *intfc;
	unsigned char *buffer2;
	int size2;
	struct usb_descriptor_header *header;
	int len, retval;
	u8 inums[USB_MAXINTERFACES], nalts[USB_MAXINTERFACES];

	memcpy(&config->desc, buffer, USB_DT_CONFIG_SIZE);
	if (config->desc.bDescriptorType != USB_DT_CONFIG ||
	    config->desc.bLength < USB_DT_CONFIG_SIZE) {
		dev_err(ddev, "invalid descriptor for config index %d: "
		    "type = 0x%X, length = %d\n", cfgidx,
		    config->desc.bDescriptorType, config->desc.bLength);
		return -EINVAL;
	}
	cfgno = config->desc.bConfigurationValue;