zc0301_urb.c

适合用于嵌入式的zc301摄像头驱动。解压缩之后放在/driver/media/video/zc0301目录下

/*	This file contains all operatinos for URB
 *
 *	It's created by WE.XCC at 2008.05.04
 *
 *	Author's E-mail:[e-mail]
 *
 */

#include <linux/module.h>
#include <linux/usb.h>
#include <linux/types.h>
#include <media/v4l2-common.h>
#include <linux/videodev.h>

#include "zc0301_debug.h"
#include "zc0301_struct.h"
#include "zc0301_descriptors.h"


void zc0301_urb_complete(struct urb *urb)
{
	struct zc0301_device *cam = NULL;
	struct zc0301_frame *f = NULL;
	u32 imagesize = 0;
	static u32 data_length = 0;
	u8 i = 0;
	int err = 0;

	if (urb == NULL)
	{
		debug_error("zc0301_urb_complete:urb is null\n");
		return;
	}
	cam = urb->context;
	if (urb->status == -ENOENT) //if uses kill, it will enable
	{
		debug_error("zc0301_urb_complete:status is -ENOENT\n");
		return;
	}
	
	if (cam->d_state & DISCONNECTED)
		return;
	if (cam->d_state & MISCONFIGED)
	{
		wake_up_interruptible(&cam->wait_frame);
		return;
	}

	if (cam->s_state == STREAM_OFF || list_empty(&cam->inqueue))
		goto resubmit;
	f = list_entry(cam->inqueue.next, struct zc0301_frame, queue);
	imagesize = 640 * 480 * 8 / 8;

	for (i = 0; i < ZC0301_PACKETS; i++)
	{
		unsigned int len = 0, status = 0;
		void *pos = NULL;
		u16 *soi = NULL;
		u8 sof = 0;

		len    = urb->iso_frame_desc[i].actual_length;
		status = urb->iso_frame_desc[i].status;
		pos    = urb->iso_frame_desc[i].offset + urb->transfer_buffer;

		if (status)
		{
			debug_error("zc0301_urb_complete:urb's packet's status is wrong\n");
			f->f_state = F_ERROR;
			continue;
		}

		sof = (*(soi = pos) == 0xd8ff); //if I have manual, I can understand it/
start_of_frame:
		if (sof)
		{
			f->f_state = F_GRABBING;
			do_gettimeofday(&f->buf.timestamp); //I don't know the function
							    //if I clear it, the driver also works well
		}
		if (f->f_state == F_GRABBING)
		{
			if (sof && data_length)
				goto end_of_frame;
			if (data_length + len > imagesize)
			{
				debug_error("exceeded imagesize\n");
				f->f_state = F_ERROR;
				continue;
			}
			memcpy(f->bufmem + data_length, pos, len);
			data_length += len;
			if (data_length == imagesize)
			{
end_of_frame:
				f->f_state = F_DONE;
				f->buf.bytesused = data_length;
				data_length = 0;
				spin_lock(&cam->queue_lock);
				list_move_tail(&f->queue, &cam->outqueue);
				//this if-else is so classical, it can speed up the display
				//the thought like DMA
				if (list_empty(&cam->inqueue))
					f = NULL;
				else
					f = list_entry(cam->inqueue.next, struct zc0301_frame, queue);
				spin_unlock(&cam->queue_lock);
				wake_up_interruptible_nr(&cam->wait_frame, 1);
				if (f == NULL)
					goto resubmit;
				else
					goto start_of_frame;
			}
		}
	}

resubmit:
	urb->dev = cam->usbdev;
	err = usb_submit_urb(urb, GFP_ATOMIC); //takes GFP_ATOMIC if in urb complete
	if (err < 0)
		debug_error("resubmit urb failed\n");
	return;
}

int zc0301_urb_start(struct zc0301_device *cam)
{
	struct usb_device *udev = NULL;
	struct usb_host_interface *altsetting = NULL;
	u16 psz = 0;
	s8 i = 0, j = 0;
	int err = 0, flag = 0;

	if (cam == NULL)
	{
		debug_error("zc0301_urb_start:cam is null\n");
		return -ENODEV;
	}
	//debug_param("%s\n", __FUNCTION__);
	udev = cam->usbdev;
	altsetting = usb_altnum_to_altsetting(usb_ifnum_to_if(udev, 0), 7);
	psz = le16_to_cpu(altsetting->endpoint[0].desc.wMaxPacketSize);

	do {
		for (i = 0; i < ZC0301_URBS; i++)
		{
			cam->transfer_buffer[i] = kzalloc(ZC0301_PACKETS * psz, GFP_KERNEL);
			if (cam->transfer_buffer[i] == NULL)
			{
				debug_error("zc0301_urb_start:alloc transfer buffer failed\n");
				err = -ENOMEM;
				flag = 1;
				break;
			}
		}

		for (i = 0; i < ZC0301_URBS; i++)
		{
			cam->urb[i] = usb_alloc_urb(ZC0301_PACKETS, GFP_KERNEL);
			if (cam->urb[i] == NULL)
			{
				debug_error("zc0301_urb_start:usb_alloc_urb failed\n");
				err = -ENOMEM;
				flag = 1;
				break;
			}
			cam->urb[i]->dev = udev;
			cam->urb[i]->context = cam;
			cam->urb[i]->pipe = usb_rcvisocpipe(udev, 1);
			cam->urb[i]->interval = 1;
			cam->urb[i]->transfer_flags = URB_ISO_ASAP;
			cam->urb[i]->transfer_buffer = cam->transfer_buffer[i];
			cam->urb[i]->complete = zc0301_urb_complete;
			cam->urb[i]->number_of_packets = ZC0301_PACKETS;
			cam->urb[i]->transfer_buffer_length = ZC0301_PACKETS * psz;
			for (j = 0; j < ZC0301_PACKETS; j++)
			{
				cam->urb[i]->iso_frame_desc[j].offset = j * psz;
				cam->urb[i]->iso_frame_desc[j].length = psz;
			}
			//debug_info("zc0301_urb_start:urb[] alloc successed\n");
		}

		err = usb_set_interface(udev, 0, 7);
		if (err)
		{
			debug_error("zc0301_urb_start:open usb interface failed\n");
			flag = 1;
			break;
		}

		for (i = 0; i < ZC0301_URBS; i++)
		{
			err = usb_submit_urb(cam->urb[i], GFP_KERNEL);
			if (err)
			{
				debug_error("zc0301_urb_start:usb_submit_urb failed\n");
				flag = 1;
				break;
			}
		}
	}while(0);

	if (flag)
	{
		debug_error("zc0301_urb_start:There is some wrong with urb start!\n");
		for (i = 0; i < ZC0301_URBS && cam->transfer_buffer[i]; i++)
			kfree(cam->transfer_buffer[i]);
		for (i = 0; i < ZC0301_URBS && cam->urb[i]; i++)
			usb_free_urb(cam->urb[i]);
		return err;
	}
	return 0;
}

int zc0301_urb_stop(struct zc0301_device *cam)
{
	struct usb_device *udev = NULL;
	s8 i = 0;
	int err = 0;
	
	if (cam == NULL)
	{
		debug_error("zc0301_urb_stop:cam is null\n");
		return -ENODEV;
	}
	//debug_param("%s\n", __FUNCTION__);
	udev = cam->usbdev;
	if (cam->d_state & DISCONNECTED)
	{
		debug_info("zc0301_urb_stop:device has been disconnected\n");
		return 0;
	}
	for (i = ZC0301_URBS-1; i >= 0; i--)
	{
		usb_kill_urb(cam->urb[i]); /*kill and unlink are so different...*/
		//usb_unlink_urb(cam->urb[i]);
		usb_free_urb(cam->urb[i]);
		kfree(cam->transfer_buffer[i]);
	}
	err = usb_set_interface(udev, 0, 0);
	if (err)
	{
		debug_error("zc0301_urb_stop:close usb interface failed\n");
		return err;
	}
	return 0;
}

EXPORT_SYMBOL(zc0301_urb_complete);
EXPORT_SYMBOL(zc0301_urb_start);
EXPORT_SYMBOL(zc0301_urb_stop);