linux-vybrid_public/drivers/media/video/ivtv/ivtv-irq.c

/* interrupt handling
    Copyright (C) 2003-2004  Kevin Thayer <nufan_wfk at yahoo.com>
    Copyright (C) 2004  Chris Kennedy <c@groovy.org>
    Copyright (C) 2005-2007  Hans Verkuil <hverkuil@xs4all.nl>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include "ivtv-driver.h"
#include "ivtv-firmware.h"
#include "ivtv-fileops.h"
#include "ivtv-queue.h"
#include "ivtv-udma.h"
#include "ivtv-irq.h"
#include "ivtv-ioctl.h"
#include "ivtv-mailbox.h"
#include "ivtv-vbi.h"
#include "ivtv-yuv.h"

#define DMA_MAGIC_COOKIE 0x000001fe

#define SLICED_VBI_PIO 1

static void ivtv_dma_dec_start(struct ivtv_stream *s);

static const int ivtv_stream_map[] = {
	IVTV_ENC_STREAM_TYPE_MPG,
	IVTV_ENC_STREAM_TYPE_YUV,
	IVTV_ENC_STREAM_TYPE_PCM,
	IVTV_ENC_STREAM_TYPE_VBI,
};

static inline int ivtv_use_pio(struct ivtv_stream *s)
{
	struct ivtv *itv = s->itv;

	return s->dma == PCI_DMA_NONE ||
	    (SLICED_VBI_PIO && s->type == IVTV_ENC_STREAM_TYPE_VBI && itv->vbi.sliced_in->service_set);
}

void ivtv_irq_work_handler(struct work_struct *work)
{
	struct ivtv *itv = container_of(work, struct ivtv, irq_work_queue);

	DEFINE_WAIT(wait);

	if (test_and_clear_bit(IVTV_F_I_WORK_HANDLER_VBI, &itv->i_flags))
		vbi_work_handler(itv);

	if (test_and_clear_bit(IVTV_F_I_WORK_HANDLER_YUV, &itv->i_flags))
		ivtv_yuv_work_handler(itv);
}

/* Determine the required DMA size, setup enough buffers in the predma queue and
   actually copy the data from the card to the buffers in case a PIO transfer is
   required for this stream.
 */
static int stream_enc_dma_append(struct ivtv_stream *s, u32 data[CX2341X_MBOX_MAX_DATA])
{
	struct ivtv *itv = s->itv;
	struct ivtv_buffer *buf;
	struct list_head *p;
	u32 bytes_needed = 0;
	u32 offset, size;
	u32 UVoffset = 0, UVsize = 0;
	int skip_bufs = s->q_predma.buffers;
	int idx = s->SG_length;
	int rc;

	/* sanity checks */
	if (s->v4l2dev == NULL) {
		IVTV_DEBUG_WARN("Stream %s not started\n", s->name);
		return -1;
	}
	if (!test_bit(IVTV_F_S_CLAIMED, &s->s_flags)) {
		IVTV_DEBUG_WARN("Stream %s not open\n", s->name);
		return -1;
	}

	/* determine offset, size and PTS for the various streams */
	switch (s->type) {
		case IVTV_ENC_STREAM_TYPE_MPG:
			offset = data[1];
			size = data[2];
			s->dma_pts = 0;
			break;

		case IVTV_ENC_STREAM_TYPE_YUV:
			offset = data[1];
			size = data[2];
			UVoffset = data[3];
			UVsize = data[4];
			s->dma_pts = ((u64) data[5] << 32) | data[6];
			break;

		case IVTV_ENC_STREAM_TYPE_PCM:
			offset = data[1] + 12;
			size = data[2] - 12;
			s->dma_pts = read_dec(offset - 8) |
				((u64)(read_dec(offset - 12)) << 32);
			if (itv->has_cx23415)
				offset += IVTV_DECODER_OFFSET;
			break;

		case IVTV_ENC_STREAM_TYPE_VBI:
			size = itv->vbi.enc_size * itv->vbi.fpi;
			offset = read_enc(itv->vbi.enc_start - 4) + 12;
			if (offset == 12) {
				IVTV_DEBUG_INFO("VBI offset == 0\n");
				return -1;
			}
			s->dma_pts = read_enc(offset - 4) | ((u64)read_enc(offset - 8) << 32);
			break;

		case IVTV_DEC_STREAM_TYPE_VBI:
			size = read_dec(itv->vbi.dec_start + 4) + 8;
			offset = read_dec(itv->vbi.dec_start) + itv->vbi.dec_start;
			s->dma_pts = 0;
			offset += IVTV_DECODER_OFFSET;
			break;
		default:
			/* shouldn't happen */
			return -1;
	}

	/* if this is the start of the DMA then fill in the magic cookie */
	if (s->SG_length == 0) {
		if (itv->has_cx23415 && (s->type == IVTV_ENC_STREAM_TYPE_PCM ||
		    s->type == IVTV_DEC_STREAM_TYPE_VBI)) {
			s->dma_backup = read_dec(offset - IVTV_DECODER_OFFSET);
			write_dec_sync(cpu_to_le32(DMA_MAGIC_COOKIE), offset - IVTV_DECODER_OFFSET);
		}
		else {
			s->dma_backup = read_enc(offset);
			write_enc_sync(cpu_to_le32(DMA_MAGIC_COOKIE), offset);
		}
		s->dma_offset = offset;
	}

	bytes_needed = size;
	if (s->type == IVTV_ENC_STREAM_TYPE_YUV) {
		/* The size for the Y samples needs to be rounded upwards to a
		   multiple of the buf_size. The UV samples then start in the
		   next buffer. */
		bytes_needed = s->buf_size * ((bytes_needed + s->buf_size - 1) / s->buf_size);
		bytes_needed += UVsize;
	}

	IVTV_DEBUG_DMA("%s %s: 0x%08x bytes at 0x%08x\n",
		ivtv_use_pio(s) ? "PIO" : "DMA", s->name, bytes_needed, offset);

	rc = ivtv_queue_move(s, &s->q_free, &s->q_full, &s->q_predma, bytes_needed);
	if (rc < 0) { /* Insufficient buffers */
		IVTV_DEBUG_WARN("Cannot obtain %d bytes for %s data transfer\n",
				bytes_needed, s->name);
		return -1;
	}
	if (rc && !s->buffers_stolen && (s->s_flags & IVTV_F_S_APPL_IO)) {
		IVTV_WARN("All %s stream buffers are full. Dropping data.\n", s->name);
		IVTV_WARN("Cause: the application is not reading fast enough.\n");
	}
	s->buffers_stolen = rc;

	/* got the buffers, now fill in SGarray (DMA) or copy the data from the card
	   to the buffers (PIO). */
	buf = list_entry(s->q_predma.list.next, struct ivtv_buffer, list);
	memset(buf->buf, 0, 128);
	list_for_each(p, &s->q_predma.list) {
		struct ivtv_buffer *buf = list_entry(p, struct ivtv_buffer, list);

		if (skip_bufs-- > 0)
			continue;
		if (!ivtv_use_pio(s)) {
			s->SGarray[idx].dst = cpu_to_le32(buf->dma_handle);
			s->SGarray[idx].src = cpu_to_le32(offset);
			s->SGarray[idx].size = cpu_to_le32(s->buf_size);
		}
		buf->bytesused = (size < s->buf_size) ? size : s->buf_size;

		/* If PIO, then copy the data from the card to the buffer */
		if (s->type == IVTV_DEC_STREAM_TYPE_VBI) {
			memcpy_fromio(buf->buf, itv->dec_mem + offset - IVTV_DECODER_OFFSET, buf->bytesused);
		}
		else if (ivtv_use_pio(s)) {
			memcpy_fromio(buf->buf, itv->enc_mem + offset, buf->bytesused);
		}

		s->q_predma.bytesused += buf->bytesused;
		size -= buf->bytesused;
		offset += s->buf_size;

		/* Sync SG buffers */
		ivtv_buf_sync_for_device(s, buf);

		if (size == 0) {	/* YUV */
			/* process the UV section */
			offset = UVoffset;
			size = UVsize;
		}
		idx++;
	}
	s->SG_length = idx;
	return 0;
}

static void dma_post(struct ivtv_stream *s)
{
	struct ivtv *itv = s->itv;
	struct ivtv_buffer *buf = NULL;
	struct list_head *p;
	u32 offset;
	u32 *u32buf;
	int x = 0;

	if (ivtv_use_pio(s)) {
		if (s->q_predma.bytesused)
			ivtv_queue_move(s, &s->q_predma, NULL, &s->q_dma, s->q_predma.bytesused);
		s->SG_length = 0;
	}
	IVTV_DEBUG_DMA("%s %s completed (%x)\n", ivtv_use_pio(s) ? "PIO" : "DMA",
			s->name, s->dma_offset);
	list_for_each(p, &s->q_dma.list) {
		buf = list_entry(p, struct ivtv_buffer, list);
		u32buf = (u32 *)buf->buf;

		/* Sync Buffer */
		ivtv_buf_sync_for_cpu(s, buf);

		if (x == 0) {
			offset = s->dma_last_offset;
			if (u32buf[offset / 4] != DMA_MAGIC_COOKIE)
			{
				for (offset = 0; offset < 64; offset++) {
					if (u32buf[offset] == DMA_MAGIC_COOKIE) {
						break;
					}
				}
				offset *= 4;
				if (offset == 256) {
					IVTV_DEBUG_WARN("%s: Couldn't find start of buffer within the first 256 bytes\n", s->name);
					offset = s->dma_last_offset;
				}
				if (s->dma_last_offset != offset)
					IVTV_DEBUG_WARN("%s: offset %d -> %d\n", s->name, s->dma_last_offset, offset);
				s->dma_last_offset = offset;
			}
			if (itv->has_cx23415 && (s->type == IVTV_ENC_STREAM_TYPE_PCM ||
						s->type == IVTV_DEC_STREAM_TYPE_VBI)) {
				write_dec_sync(0, s->dma_offset - IVTV_DECODER_OFFSET);
			}
			else {
				write_enc_sync(0, s->dma_offset);
			}
			if (offset) {
				buf->bytesused -= offset;
				memcpy(buf->buf, buf->buf + offset, buf->bytesused + offset);
			}
			*u32buf = cpu_to_le32(s->dma_backup);
		}
		x++;
		/* flag byteswap ABCD -> DCBA for MPG & VBI data outside irq */
		if (s->type == IVTV_ENC_STREAM_TYPE_MPG ||
		    s->type == IVTV_ENC_STREAM_TYPE_VBI)
			set_bit(IVTV_F_B_NEED_BUF_SWAP, &buf->b_flags);
	}
	if (buf)
		buf->bytesused += s->dma_last_offset;
	if (buf && s->type == IVTV_DEC_STREAM_TYPE_VBI) {
		/* Parse and Groom VBI Data */
		s->q_dma.bytesused -= buf->bytesused;
		ivtv_process_vbi_data(itv, buf, 0, s->type);
		s->q_dma.bytesused += buf->bytesused;
		if (s->id == -1) {
			ivtv_queue_move(s, &s->q_dma, NULL, &s->q_free, 0);
			return;
		}
	}
	ivtv_queue_move(s, &s->q_dma, NULL, &s->q_full, s->q_dma.bytesused);
	if (s->id != -1)
		wake_up(&s->waitq);
}

void ivtv_dma_stream_dec_prepare(struct ivtv_stream *s, u32 offset, int lock)
{
	struct ivtv *itv = s->itv;
	struct ivtv_buffer *buf;
	struct list_head *p;
	u32 y_size = itv->params.height * itv->params.width;
	u32 uv_offset = offset + IVTV_YUV_BUFFER_UV_OFFSET;
	int y_done = 0;
	int bytes_written = 0;
	unsigned long flags = 0;
	int idx = 0;

	IVTV_DEBUG_DMA("DEC PREPARE DMA %s: %08x %08x\n", s->name, s->q_predma.bytesused, offset);
	buf = list_entry(s->q_predma.list.next, struct ivtv_buffer, list);
	list_for_each(p, &s->q_predma.list) {
		struct ivtv_buffer *buf = list_entry(p, struct ivtv_buffer, list);

		/* YUV UV Offset from Y Buffer */
		if (s->type == IVTV_DEC_STREAM_TYPE_YUV && !y_done && bytes_written >= y_size) {
			offset = uv_offset;
			y_done = 1;
		}
		s->SGarray[idx].src = cpu_to_le32(buf->dma_handle);
		s->SGarray[idx].dst = cpu_to_le32(offset);
		s->SGarray[idx].size = cpu_to_le32(buf->bytesused);

		offset += buf->bytesused;
		bytes_written += buf->bytesused;

		/* Sync SG buffers */
		ivtv_buf_sync_for_device(s, buf);
		idx++;
	}
	s->SG_length = idx;

	/* Mark last buffer size for Interrupt flag */
	s->SGarray[s->SG_length - 1].size |= cpu_to_le32(0x80000000);

	/* Sync Hardware SG List of buffers */
	ivtv_stream_sync_for_device(s);
	if (lock)
		spin_lock_irqsave(&itv->dma_reg_lock, flags);
	if (!test_bit(IVTV_F_I_DMA, &itv->i_flags)) {
		ivtv_dma_dec_start(s);
	}
	else {
		set_bit(IVTV_F_S_DMA_PENDING, &s->s_flags);
	}
	if (lock)
		spin_unlock_irqrestore(&itv->dma_reg_lock, flags);
}

/* start the encoder DMA */
static void ivtv_dma_enc_start(struct ivtv_stream *s)
{
	struct ivtv *itv = s->itv;
	struct ivtv_stream *s_vbi = &itv->streams[IVTV_ENC_STREAM_TYPE_VBI];
	int i;

	if (s->q_predma.bytesused)
		ivtv_queue_move(s, &s->q_predma, NULL, &s->q_dma, s->q_predma.bytesused);
	IVTV_DEBUG_DMA("start DMA for %s\n", s->name);
	s->SGarray[s->SG_length - 1].size = cpu_to_le32(le32_to_cpu(s->SGarray[s->SG_length - 1].size) + 256);

	/* If this is an MPEG stream, and VBI data is also pending, then append the
	   VBI DMA to the MPEG DMA and transfer both sets of data at once.

	   VBI DMA is a second class citizen compared to MPEG and mixing them together
	   will confuse the firmware (the end of a VBI DMA is seen as the end of a
	   MPEG DMA, thus effectively dropping an MPEG frame). So instead we make
	   sure we only use the MPEG DMA to transfer the VBI DMA if both are in
	   use. This way no conflicts occur. */
	clear_bit(IVTV_F_S_DMA_HAS_VBI, &s->s_flags);
	if (s->type == IVTV_ENC_STREAM_TYPE_MPG && s_vbi->SG_length &&
			s->SG_length + s_vbi->SG_length <= s->buffers) {
		ivtv_queue_move(s_vbi, &s_vbi->q_predma, NULL, &s_vbi->q_dma, s_vbi->q_predma.bytesused);
		s_vbi->SGarray[s_vbi->SG_length - 1].size = cpu_to_le32(le32_to_cpu(s_vbi->SGarray[s->SG_length - 1].size) + 256);
		for (i = 0; i < s_vbi->SG_length; i++) {
			s->SGarray[s->SG_length++] = s_vbi->SGarray[i];
		}
		itv->vbi.dma_offset = s_vbi->dma_offset;
		s_vbi->SG_length = 0;
		set_bit(IVTV_F_S_DMA_HAS_VBI, &s->s_flags);
		IVTV_DEBUG_DMA("include DMA for %s\n", s->name);
	}

	/* Mark last buffer size for Interrupt flag */
	s->SGarray[s->SG_length - 1].size |= cpu_to_le32(0x80000000);

	/* Sync Hardware SG List of buffers */
	ivtv_stream_sync_for_device(s);
	write_reg(s->SG_handle, IVTV_REG_ENCDMAADDR);
	write_reg_sync(read_reg(IVTV_REG_DMAXFER) | 0x02, IVTV_REG_DMAXFER);
	set_bit(IVTV_F_I_DMA, &itv->i_flags);
	itv->cur_dma_stream = s->type;
	itv->dma_timer.expires = jiffies + HZ / 10;
	add_timer(&itv->dma_timer);
}

static void ivtv_dma_dec_start(struct ivtv_stream *s)
{
	struct ivtv *itv = s->itv;

	if (s->q_predma.bytesused)
		ivtv_queue_move(s, &s->q_predma, NULL, &s->q_dma, s->q_predma.bytesused);
	IVTV_DEBUG_DMA("start DMA for %s\n", s->name);
	/* put SG Handle into register 0x0c */
	write_reg(s->SG_handle, IVTV_REG_DECDMAADDR);
	write_reg_sync(read_reg(IVTV_REG_DMAXFER) | 0x01, IVTV_REG_DMAXFER);
	set_bit(IVTV_F_I_DMA, &itv->i_flags);
	itv->cur_dma_stream = s->type;
	itv->dma_timer.expires = jiffies + HZ / 10;
	add_timer(&itv->dma_timer);
}

static void ivtv_irq_dma_read(struct ivtv *itv)
{
	struct ivtv_stream *s = NULL;
	struct ivtv_buffer *buf;
	int hw_stream_type;

	IVTV_DEBUG_IRQ("DEC DMA READ\n");
	del_timer(&itv->dma_timer);
	if (read_reg(IVTV_REG_DMASTATUS) & 0x14) {
		IVTV_DEBUG_WARN("DEC DMA ERROR %x\n", read_reg(IVTV_REG_DMASTATUS));
		write_reg(read_reg(IVTV_REG_DMASTATUS) & 3, IVTV_REG_DMASTATUS);
	}
	if (!test_bit(IVTV_F_I_UDMA, &itv->i_flags)) {
		if (test_bit(IVTV_F_I_DEC_YUV, &itv->i_flags)) {
			s = &itv->streams[IVTV_DEC_STREAM_TYPE_YUV];
			hw_stream_type = 2;
		}
		else {
			s = &itv->streams[IVTV_DEC_STREAM_TYPE_MPG];
			hw_stream_type = 0;
		}
		IVTV_DEBUG_DMA("DEC DATA READ %s: %d\n", s->name, s->q_dma.bytesused);

		ivtv_stream_sync_for_cpu(s);

		/* For some reason must kick the firmware, like PIO mode,
		   I think this tells the firmware we are done and the size
		   of the xfer so it can calculate what we need next.
		   I think we can do this part ourselves but would have to
		   fully calculate xfer info ourselves and not use interrupts
		 */
		ivtv_vapi(itv, CX2341X_DEC_SCHED_DMA_FROM_HOST, 3, 0, s->q_dma.bytesused,
				hw_stream_type);

		/* Free last DMA call */
		while ((buf = ivtv_dequeue(s, &s->q_dma)) != NULL) {
			ivtv_buf_sync_for_cpu(s, buf);
			ivtv_enqueue(s, buf, &s->q_free);
		}
		wake_up(&s->waitq);
	}
	clear_bit(IVTV_F_I_UDMA, &itv->i_flags);
	clear_bit(IVTV_F_I_DMA, &itv->i_flags);
	itv->cur_dma_stream = -1;
	wake_up(&itv->dma_waitq);
}

static void ivtv_irq_enc_dma_complete(struct ivtv *itv)
{
	u32 data[CX2341X_MBOX_MAX_DATA];
	struct ivtv_stream *s;

	del_timer(&itv->dma_timer);
	ivtv_api_get_data(&itv->enc_mbox, IVTV_MBOX_DMA_END, data);
	IVTV_DEBUG_IRQ("ENC DMA COMPLETE %x %d\n", data[0], data[1]);
	if (test_and_clear_bit(IVTV_F_I_ENC_VBI, &itv->i_flags))
		data[1] = 3;
	else if (data[1] > 2)
		return;
	s = &itv->streams[ivtv_stream_map[data[1]]];
	if (data[0] & 0x18) {
		IVTV_DEBUG_WARN("ENC DMA ERROR %x\n", data[0]);
		write_reg(read_reg(IVTV_REG_DMASTATUS) & 3, IVTV_REG_DMASTATUS);
		ivtv_vapi(itv, CX2341X_ENC_SCHED_DMA_TO_HOST, 3, 0, 0, data[1]);
	}
	s->SG_length = 0;
	clear_bit(IVTV_F_I_DMA, &itv->i_flags);
	itv->cur_dma_stream = -1;
	dma_post(s);
	ivtv_stream_sync_for_cpu(s);
	if (test_and_clear_bit(IVTV_F_S_DMA_HAS_VBI, &s->s_flags)) {
		u32 tmp;

		s = &itv->streams[IVTV_ENC_STREAM_TYPE_VBI];
		tmp = s->dma_offset;
		s->dma_offset = itv->vbi.dma_offset;
		dma_post(s);
		s->dma_offset = tmp;
	}
	wake_up(&itv->dma_waitq);
}

static void ivtv_irq_dma_err(struct ivtv *itv)
{
	u32 data[CX2341X_MBOX_MAX_DATA];

	del_timer(&itv->dma_timer);
	ivtv_api_get_data(&itv->enc_mbox, IVTV_MBOX_DMA_END, data);
	IVTV_DEBUG_WARN("DMA ERROR %08x %08x %08x %d\n", data[0], data[1],
					read_reg(IVTV_REG_DMASTATUS), itv->cur_dma_stream);
	if (!test_bit(IVTV_F_I_UDMA, &itv->i_flags) &&
	    itv->cur_dma_stream >= 0 && itv->cur_dma_stream < IVTV_MAX_STREAMS) {
		struct ivtv_stream *s = &itv->streams[itv->cur_dma_stream];

		/* retry */
		write_reg(read_reg(IVTV_REG_DMASTATUS) & 3, IVTV_REG_DMASTATUS);
		if (s->type >= IVTV_DEC_STREAM_TYPE_MPG)
			ivtv_dma_dec_start(s);
		else
			ivtv_dma_enc_start(s);
		return;
	}
	clear_bit(IVTV_F_I_UDMA, &itv->i_flags);
	clear_bit(IVTV_F_I_DMA, &itv->i_flags);
	itv->cur_dma_stream = -1;
	wake_up(&itv->dma_waitq);
}

static void ivtv_irq_enc_start_cap(struct ivtv *itv)
{
	u32 data[CX2341X_MBOX_MAX_DATA];
	struct ivtv_stream *s;

	/* Get DMA destination and size arguments from card */
	ivtv_api_get_data(&itv->enc_mbox, IVTV_MBOX_DMA, data);
	IVTV_DEBUG_IRQ("ENC START CAP %d: %08x %08x\n", data[0], data[1], data[2]);

	if (data[0] > 2 || data[1] == 0 || data[2] == 0) {
		IVTV_DEBUG_WARN("Unknown input: %08x %08x %08x\n",
				data[0], data[1], data[2]);
		return;
	}
	clear_bit(IVTV_F_I_ENC_VBI, &itv->i_flags);
	s = &itv->streams[ivtv_stream_map[data[0]]];
	if (!stream_enc_dma_append(s, data)) {
		if (ivtv_use_pio(s)) {
			dma_post(s);
			ivtv_vapi(itv, CX2341X_ENC_SCHED_DMA_TO_HOST, 3, 0, 0, data[0]);
		}
		else {
			set_bit(IVTV_F_S_DMA_PENDING, &s->s_flags);
		}
	}
}

static void ivtv_irq_enc_vbi_cap(struct ivtv *itv)
{
	struct ivtv_stream *s_mpg = &itv->streams[IVTV_ENC_STREAM_TYPE_MPG];
	u32 data[CX2341X_MBOX_MAX_DATA];
	struct ivtv_stream *s;

	IVTV_DEBUG_IRQ("ENC START VBI CAP\n");
	s = &itv->streams[IVTV_ENC_STREAM_TYPE_VBI];

	if (ivtv_use_pio(s)) {
		if (stream_enc_dma_append(s, data))
			return;
		if (s->q_predma.bytesused)
			ivtv_queue_move(s, &s->q_predma, NULL, &s->q_dma, s->q_predma.bytesused);
		s->SG_length = 0;
		dma_post(s);
		return;
	}
	/* If more than two VBI buffers are pending, then
	   clear the old ones and start with this new one.
	   This can happen during transition stages when MPEG capturing is
	   started, but the first interrupts haven't arrived yet. During
	   that period VBI requests can accumulate without being able to
	   DMA the data. Since at most four VBI DMA buffers are available,
	   we just drop the old requests when there are already three
	   requests queued. */
	if (s->SG_length > 2) {
		struct list_head *p;
		list_for_each(p, &s->q_predma.list) {
			struct ivtv_buffer *buf = list_entry(p, struct ivtv_buffer, list);
			ivtv_buf_sync_for_cpu(s, buf);
		}
		ivtv_queue_move(s, &s->q_predma, NULL, &s->q_free, 0);
		s->SG_length = 0;
	}
	/* if we can append the data, and the MPEG stream isn't capturing,
	   then start a DMA request for just the VBI data. */
	if (!stream_enc_dma_append(s, data) &&
			!test_bit(IVTV_F_S_STREAMING, &s_mpg->s_flags)) {
		set_bit(IVTV_F_I_ENC_VBI, &itv->i_flags);
		set_bit(IVTV_F_S_DMA_PENDING, &s->s_flags);
	}
}

static void ivtv_irq_dev_vbi_reinsert(struct ivtv *itv)
{
	u32 data[CX2341X_MBOX_MAX_DATA];
	struct ivtv_stream *s = &itv->streams[IVTV_DEC_STREAM_TYPE_VBI];

	IVTV_DEBUG_IRQ("DEC VBI REINSERT\n");
	if (test_bit(IVTV_F_S_CLAIMED, &s->s_flags) &&
			!stream_enc_dma_append(s, data)) {
		dma_post(s);
	}
}

static void ivtv_irq_dec_data_req(struct ivtv *itv)
{
	u32 data[CX2341X_MBOX_MAX_DATA];
	struct ivtv_stream *s;

	/* YUV or MPG */
	ivtv_api_get_data(&itv->dec_mbox, IVTV_MBOX_DMA, data);

	if (test_bit(IVTV_F_I_DEC_YUV, &itv->i_flags)) {
		itv->dma_data_req_size = itv->params.width * itv->params.height * 3 / 2;
		itv->dma_data_req_offset = data[1] ? data[1] : yuv_offset[0];
		s = &itv->streams[IVTV_DEC_STREAM_TYPE_YUV];
	}
	else {
		itv->dma_data_req_size = data[2] >= 0x10000 ? 0x10000 : data[2];
		itv->dma_data_req_offset = data[1];
		s = &itv->streams[IVTV_DEC_STREAM_TYPE_MPG];
	}
	IVTV_DEBUG_IRQ("DEC DATA REQ %s: %d %08x %u\n", s->name, s->q_full.bytesused,
		       itv->dma_data_req_offset, itv->dma_data_req_size);
	if (itv->dma_data_req_size == 0 || s->q_full.bytesused < itv->dma_data_req_size) {
		set_bit(IVTV_F_S_NEEDS_DATA, &s->s_flags);
	}
	else {
		clear_bit(IVTV_F_S_NEEDS_DATA, &s->s_flags);
		ivtv_queue_move(s, &s->q_full, NULL, &s->q_predma, itv->dma_data_req_size);
		ivtv_dma_stream_dec_prepare(s, itv->dma_data_req_offset + IVTV_DECODER_OFFSET, 0);
	}
}

static void ivtv_irq_vsync(struct ivtv *itv)
{
	/* The vsync interrupt is unusual in that it won't clear until
	 * the end of the first line for the current field, at which
	 * point it clears itself. This can result in repeated vsync
	 * interrupts, or a missed vsync. Read some of the registers
	 * to determine the line being displayed and ensure we handle
	 * one vsync per frame.
	 */
	unsigned int frame = read_reg(0x28c0) & 1;
	int last_dma_frame = atomic_read(&itv->yuv_info.next_dma_frame);

	if (0) IVTV_DEBUG_IRQ("DEC VSYNC\n");

	if (((frame ^ itv->yuv_info.lace_sync_field) == 0 && ((itv->lastVsyncFrame & 1) ^ itv->yuv_info.lace_sync_field)) ||
			(frame != (itv->lastVsyncFrame & 1) && !itv->yuv_info.frame_interlaced)) {
		int next_dma_frame = last_dma_frame;

		if (next_dma_frame >= 0 && next_dma_frame != atomic_read(&itv->yuv_info.next_fill_frame)) {
			write_reg(yuv_offset[next_dma_frame] >> 4, 0x82c);
			write_reg((yuv_offset[next_dma_frame] + IVTV_YUV_BUFFER_UV_OFFSET) >> 4, 0x830);
			write_reg(yuv_offset[next_dma_frame] >> 4, 0x834);
			write_reg((yuv_offset[next_dma_frame] + IVTV_YUV_BUFFER_UV_OFFSET) >> 4, 0x838);
			next_dma_frame = (next_dma_frame + 1) & 0x3;
			atomic_set(&itv->yuv_info.next_dma_frame, next_dma_frame);
		}
	}
	if (frame != (itv->lastVsyncFrame & 1)) {
		struct ivtv_stream *s = ivtv_get_output_stream(itv);
		int work = 0;

		itv->lastVsyncFrame += 1;
		if (frame == 0) {
			clear_bit(IVTV_F_I_VALID_DEC_TIMINGS, &itv->i_flags);
			clear_bit(IVTV_F_I_EV_VSYNC_FIELD, &itv->i_flags);
		}
		else {
			set_bit(IVTV_F_I_EV_VSYNC_FIELD, &itv->i_flags);
		}
		if (test_bit(IVTV_F_I_EV_VSYNC_ENABLED, &itv->i_flags)) {
			set_bit(IVTV_F_I_EV_VSYNC, &itv->i_flags);
			wake_up(&itv->event_waitq);
		}
		wake_up(&itv->vsync_waitq);
		if (s)
			wake_up(&s->waitq);

		/* Send VBI to saa7127 */
		if (frame) {
			set_bit(IVTV_F_I_WORK_HANDLER_VBI, &itv->i_flags);
			work = 1;
		}

		/* Check if we need to update the yuv registers */
		if ((itv->yuv_info.yuv_forced_update || itv->yuv_info.new_frame_info[last_dma_frame].update) && last_dma_frame != -1) {
			if (!itv->yuv_info.new_frame_info[last_dma_frame].update)
				last_dma_frame = (last_dma_frame - 1) & 3;

			if (itv->yuv_info.new_frame_info[last_dma_frame].src_w) {
				itv->yuv_info.update_frame = last_dma_frame;
				itv->yuv_info.new_frame_info[last_dma_frame].update = 0;
				itv->yuv_info.yuv_forced_update = 0;
				set_bit(IVTV_F_I_WORK_HANDLER_YUV, &itv->i_flags);
				work = 1;
			}
		}
		if (work)
			queue_work(itv->irq_work_queues, &itv->irq_work_queue);
	}
}

#define IVTV_IRQ_DMA (IVTV_IRQ_DMA_READ | IVTV_IRQ_ENC_DMA_COMPLETE | IVTV_IRQ_DMA_ERR | IVTV_IRQ_ENC_START_CAP | IVTV_IRQ_ENC_VBI_CAP | IVTV_IRQ_DEC_DATA_REQ)

irqreturn_t ivtv_irq_handler(int irq, void *dev_id)
{
	struct ivtv *itv = (struct ivtv *)dev_id;
	u32 combo;
	u32 stat;
	int i;
	u8 vsync_force = 0;

	spin_lock(&itv->dma_reg_lock);
	/* get contents of irq status register */
	stat = read_reg(IVTV_REG_IRQSTATUS);

	combo = ~itv->irqmask & stat;

	/* Clear out IRQ */
	if (combo) write_reg(combo, IVTV_REG_IRQSTATUS);

	if (0 == combo) {
		/* The vsync interrupt is unusual and clears itself. If we
		 * took too long, we may have missed it. Do some checks
		 */
		if (~itv->irqmask & IVTV_IRQ_DEC_VSYNC) {
			/* vsync is enabled, see if we're in a new field */
			if ((itv->lastVsyncFrame & 1) != (read_reg(0x28c0) & 1)) {
				/* New field, looks like we missed it */
				IVTV_DEBUG_YUV("VSync interrupt missed %d\n",read_reg(0x28c0)>>16);
				vsync_force = 1;
			}
		}

		if (!vsync_force) {
			/* No Vsync expected, wasn't for us */
			spin_unlock(&itv->dma_reg_lock);
			return IRQ_NONE;
		}
	}

	/* Exclude interrupts noted below from the output, otherwise the log is flooded with
	   these messages */
	if (combo & ~0xff6d0400)
		IVTV_DEBUG_IRQ("======= valid IRQ bits: 0x%08x ======\n", combo);

	if (combo & IVTV_IRQ_DEC_DMA_COMPLETE) {
		IVTV_DEBUG_IRQ("DEC DMA COMPLETE\n");
	}

	if (combo & IVTV_IRQ_DMA_READ) {
		ivtv_irq_dma_read(itv);
	}

	if (combo & IVTV_IRQ_ENC_DMA_COMPLETE) {
		ivtv_irq_enc_dma_complete(itv);
	}

	if (combo & IVTV_IRQ_DMA_ERR) {
		ivtv_irq_dma_err(itv);
	}

	if (combo & IVTV_IRQ_ENC_START_CAP) {
		ivtv_irq_enc_start_cap(itv);
	}

	if (combo & IVTV_IRQ_ENC_VBI_CAP) {
		ivtv_irq_enc_vbi_cap(itv);
	}

	if (combo & IVTV_IRQ_DEC_VBI_RE_INSERT) {
		ivtv_irq_dev_vbi_reinsert(itv);
	}

	if (combo & IVTV_IRQ_ENC_EOS) {
		IVTV_DEBUG_IRQ("ENC EOS\n");
		set_bit(IVTV_F_I_EOS, &itv->i_flags);
		wake_up(&itv->cap_w);
	}

	if (combo & IVTV_IRQ_DEC_DATA_REQ) {
		ivtv_irq_dec_data_req(itv);
	}

	/* Decoder Vertical Sync - We can't rely on 'combo', so check if vsync enabled */
	if (~itv->irqmask & IVTV_IRQ_DEC_VSYNC) {
		ivtv_irq_vsync(itv);
	}

	if (combo & IVTV_IRQ_ENC_VIM_RST) {
		IVTV_DEBUG_IRQ("VIM RST\n");
		/*ivtv_vapi(itv, CX2341X_ENC_REFRESH_INPUT, 0); */
	}

	if (combo & IVTV_IRQ_DEC_AUD_MODE_CHG) {
		IVTV_DEBUG_INFO("Stereo mode changed\n");
	}

	if ((combo & IVTV_IRQ_DMA) && !test_bit(IVTV_F_I_DMA, &itv->i_flags)) {
		for (i = 0; i < IVTV_MAX_STREAMS; i++) {
			int idx = (i + itv->irq_rr_idx++) % IVTV_MAX_STREAMS;
			struct ivtv_stream *s = &itv->streams[idx];

			if (!test_and_clear_bit(IVTV_F_S_DMA_PENDING, &s->s_flags))
				continue;
			if (s->type >= IVTV_DEC_STREAM_TYPE_MPG)
				ivtv_dma_dec_start(s);
			else
				ivtv_dma_enc_start(s);
			break;
		}
		if (i == IVTV_MAX_STREAMS && test_and_clear_bit(IVTV_F_I_UDMA_PENDING, &itv->i_flags)) {
			ivtv_udma_start(itv);
		}
	}

	spin_unlock(&itv->dma_reg_lock);

	/* If we've just handled a 'forced' vsync, it's safest to say it
	 * wasn't ours. Another device may have triggered it at just
	 * the right time.
	 */
	return vsync_force ? IRQ_NONE : IRQ_HANDLED;
}

void ivtv_unfinished_dma(unsigned long arg)
{
	struct ivtv *itv = (struct ivtv *)arg;

	if (!test_bit(IVTV_F_I_DMA, &itv->i_flags))
		return;
	IVTV_ERR("DMA TIMEOUT %08x %d\n", read_reg(IVTV_REG_DMASTATUS), itv->cur_dma_stream);

	write_reg(read_reg(IVTV_REG_DMASTATUS) & 3, IVTV_REG_DMASTATUS);
	clear_bit(IVTV_F_I_UDMA, &itv->i_flags);
	clear_bit(IVTV_F_I_DMA, &itv->i_flags);
	itv->cur_dma_stream = -1;
	wake_up(&itv->dma_waitq);
}