xref: /kernel/linux/linux-6.6/drivers/media/pci/bt8xx/bttv-vbi.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*

    bttv - Bt848 frame grabber driver
    vbi interface

    (c) 2002 Gerd Knorr <kraxel@bytesex.org>

    Copyright (C) 2005, 2006 Michael H. Schimek <mschimek@gmx.at>
    Sponsored by OPQ Systems AB

*/

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/kdev_t.h>
#include <media/v4l2-ioctl.h>
#include <asm/io.h>
#include "bttvp.h"

/* Offset from line sync pulse leading edge (0H) to start of VBI capture,
   in fCLKx2 pixels.  According to the datasheet, VBI capture starts
   VBI_HDELAY fCLKx1 pixels from the tailing edgeof /HRESET, and /HRESET
   is 64 fCLKx1 pixels wide.  VBI_HDELAY is set to 0, so this should be
   (64 + 0) * 2 = 128 fCLKx2 pixels.  But it's not!  The datasheet is
   Just Plain Wrong.  The real value appears to be different for
   different revisions of the bt8x8 chips, and to be affected by the
   horizontal scaling factor.  Experimentally, the value is measured
   to be about 244.  */
#define VBI_OFFSET 244

static unsigned int vbibufs = 4;
static unsigned int vbi_debug;

module_param(vbibufs,   int, 0444);
module_param(vbi_debug, int, 0644);
MODULE_PARM_DESC(vbibufs,"number of vbi buffers, range 2-32, default 4");
MODULE_PARM_DESC(vbi_debug,"vbi code debug messages, default is 0 (no)");

#ifdef dprintk
# undef dprintk
#endif
#define dprintk(fmt, ...)						\
do {									\
	if (vbi_debug)							\
		pr_debug("%d: " fmt, btv->c.nr, ##__VA_ARGS__);		\
} while (0)

#define IMAGE_SIZE(fmt) \
	(((fmt)->count[0] + (fmt)->count[1]) * (fmt)->samples_per_line)

/* ----------------------------------------------------------------------- */
/* vbi risc code + mm                                                      */

static int queue_setup_vbi(struct vb2_queue *q, unsigned int *num_buffers,
			   unsigned int *num_planes, unsigned int sizes[],
			   struct device *alloc_devs[])
{
	struct bttv *btv = vb2_get_drv_priv(q);
	unsigned int size = IMAGE_SIZE(&btv->vbi_fmt.fmt);

	if (*num_planes)
		return sizes[0] < size ? -EINVAL : 0;
	*num_planes = 1;
	sizes[0] = size;

	return 0;
}

static void buf_queue_vbi(struct vb2_buffer *vb)
{
	struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
	struct vb2_queue *vq = vb->vb2_queue;
	struct bttv *btv = vb2_get_drv_priv(vq);
	struct bttv_buffer *buf = container_of(vbuf, struct bttv_buffer, vbuf);
	unsigned long flags;

	spin_lock_irqsave(&btv->s_lock, flags);
	if (list_empty(&btv->vcapture)) {
		btv->loop_irq = BT848_RISC_VBI;
		if (vb2_is_streaming(&btv->capq))
			btv->loop_irq |= BT848_RISC_VIDEO;
		bttv_set_dma(btv, BT848_CAP_CTL_CAPTURE_VBI_ODD |
			     BT848_CAP_CTL_CAPTURE_VBI_EVEN);
	}
	list_add_tail(&buf->list, &btv->vcapture);
	spin_unlock_irqrestore(&btv->s_lock, flags);
}

static int buf_prepare_vbi(struct vb2_buffer *vb)
{
	int ret = 0;
	struct vb2_queue *vq = vb->vb2_queue;
	struct bttv *btv = vb2_get_drv_priv(vq);
	struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
	struct bttv_buffer *buf = container_of(vbuf, struct bttv_buffer, vbuf);
	unsigned int size = IMAGE_SIZE(&btv->vbi_fmt.fmt);

	if (vb2_plane_size(vb, 0) < size)
		return -EINVAL;
	vb2_set_plane_payload(vb, 0, size);
	buf->vbuf.field = V4L2_FIELD_NONE;
	ret = bttv_buffer_risc_vbi(btv, buf);

	return ret;
}

static void buf_cleanup_vbi(struct vb2_buffer *vb)
{
	struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
	struct bttv_buffer *buf = container_of(vbuf, struct bttv_buffer, vbuf);
	struct vb2_queue *vq = vb->vb2_queue;
	struct bttv *btv = vb2_get_drv_priv(vq);

	btcx_riscmem_free(btv->c.pci, &buf->top);
	btcx_riscmem_free(btv->c.pci, &buf->bottom);
}

static int start_streaming_vbi(struct vb2_queue *q, unsigned int count)
{
	int seqnr = 0;
	struct bttv_buffer *buf;
	struct bttv *btv = vb2_get_drv_priv(q);

	btv->framedrop = 0;
	if (!check_alloc_btres_lock(btv, RESOURCE_VBI)) {
		if (btv->field_count)
			seqnr++;
		while (!list_empty(&btv->vcapture)) {
			buf = list_entry(btv->vcapture.next,
					 struct bttv_buffer, list);
			list_del(&buf->list);
			buf->vbuf.sequence = (btv->field_count >> 1) + seqnr++;
			vb2_buffer_done(&buf->vbuf.vb2_buf,
					VB2_BUF_STATE_QUEUED);
		}
		return -EBUSY;
	}
	if (!vb2_is_streaming(&btv->capq)) {
		init_irqreg(btv);
		btv->field_count = 0;
	}
	return 0;
}

static void stop_streaming_vbi(struct vb2_queue *q)
{
	struct bttv *btv = vb2_get_drv_priv(q);
	unsigned long flags;

	vb2_wait_for_all_buffers(q);
	spin_lock_irqsave(&btv->s_lock, flags);
	free_btres_lock(btv, RESOURCE_VBI);
	if (!vb2_is_streaming(&btv->capq)) {
		/* stop field counter */
		btand(~BT848_INT_VSYNC, BT848_INT_MASK);
	}
	spin_unlock_irqrestore(&btv->s_lock, flags);
}

const struct vb2_ops bttv_vbi_qops = {
	.queue_setup    = queue_setup_vbi,
	.buf_queue      = buf_queue_vbi,
	.buf_prepare    = buf_prepare_vbi,
	.buf_cleanup	= buf_cleanup_vbi,
	.start_streaming = start_streaming_vbi,
	.stop_streaming = stop_streaming_vbi,
	.wait_prepare   = vb2_ops_wait_prepare,
	.wait_finish    = vb2_ops_wait_finish,
};

/* ----------------------------------------------------------------------- */

static int try_fmt(struct v4l2_vbi_format *f, const struct bttv_tvnorm *tvnorm,
			__s32 crop_start)
{
	__s32 min_start, max_start, max_end, f2_offset;
	unsigned int i;

	/* For compatibility with earlier driver versions we must pretend
	   the VBI and video capture window may overlap. In reality RISC
	   magic aborts VBI capturing at the first line of video capturing,
	   leaving the rest of the buffer unchanged, usually all zero.
	   VBI capturing must always start before video capturing. >> 1
	   because cropping counts field lines times two. */
	min_start = tvnorm->vbistart[0];
	max_start = (crop_start >> 1) - 1;
	max_end = (tvnorm->cropcap.bounds.top
		   + tvnorm->cropcap.bounds.height) >> 1;

	if (min_start > max_start)
		return -EBUSY;

	WARN_ON(max_start >= max_end);

	f->sampling_rate    = tvnorm->Fsc;
	f->samples_per_line = VBI_BPL;
	f->sample_format    = V4L2_PIX_FMT_GREY;
	f->offset           = VBI_OFFSET;

	f2_offset = tvnorm->vbistart[1] - tvnorm->vbistart[0];

	for (i = 0; i < 2; ++i) {
		if (0 == f->count[i]) {
			/* No data from this field. We leave f->start[i]
			   alone because VIDIOCSVBIFMT is w/o and EINVALs
			   when a driver does not support exactly the
			   requested parameters. */
		} else {
			s64 start, count;

			start = clamp(f->start[i], min_start, max_start);
			/* s64 to prevent overflow. */
			count = (s64) f->start[i] + f->count[i] - start;
			f->start[i] = start;
			f->count[i] = clamp(count, (s64) 1,
					    max_end - start);
		}

		min_start += f2_offset;
		max_start += f2_offset;
		max_end += f2_offset;
	}

	if (0 == (f->count[0] | f->count[1])) {
		/* As in earlier driver versions. */
		f->start[0] = tvnorm->vbistart[0];
		f->start[1] = tvnorm->vbistart[1];
		f->count[0] = 1;
		f->count[1] = 1;
	}

	f->flags = 0;

	f->reserved[0] = 0;
	f->reserved[1] = 0;

	return 0;
}

int bttv_try_fmt_vbi_cap(struct file *file, void *f, struct v4l2_format *frt)
{
	struct bttv *btv = video_drvdata(file);
	const struct bttv_tvnorm *tvnorm;
	__s32 crop_start;

	mutex_lock(&btv->lock);

	tvnorm = &bttv_tvnorms[btv->tvnorm];
	crop_start = btv->crop_start;

	mutex_unlock(&btv->lock);

	return try_fmt(&frt->fmt.vbi, tvnorm, crop_start);
}


int bttv_s_fmt_vbi_cap(struct file *file, void *f, struct v4l2_format *frt)
{
	struct bttv *btv = video_drvdata(file);
	const struct bttv_tvnorm *tvnorm;
	__s32 start1, end;
	int rc;

	mutex_lock(&btv->lock);

	rc = -EBUSY;
	if (btv->resources & RESOURCE_VBI)
		goto fail;

	tvnorm = &bttv_tvnorms[btv->tvnorm];

	rc = try_fmt(&frt->fmt.vbi, tvnorm, btv->crop_start);
	if (0 != rc)
		goto fail;

	start1 = frt->fmt.vbi.start[1] - tvnorm->vbistart[1] +
		tvnorm->vbistart[0];

	/* First possible line of video capturing. Should be
	   max(f->start[0] + f->count[0], start1 + f->count[1]) * 2
	   when capturing both fields. But for compatibility we must
	   pretend the VBI and video capture window may overlap,
	   so end = start + 1, the lowest possible value, times two
	   because vbi_fmt.end counts field lines times two. */
	end = max(frt->fmt.vbi.start[0], start1) * 2 + 2;

	btv->vbi_fmt.fmt = frt->fmt.vbi;
	btv->vbi_fmt.tvnorm = tvnorm;
	btv->vbi_fmt.end = end;

	rc = 0;

 fail:
	mutex_unlock(&btv->lock);

	return rc;
}


int bttv_g_fmt_vbi_cap(struct file *file, void *f, struct v4l2_format *frt)
{
	const struct bttv_tvnorm *tvnorm;
	struct bttv *btv = video_drvdata(file);

	frt->fmt.vbi = btv->vbi_fmt.fmt;

	tvnorm = &bttv_tvnorms[btv->tvnorm];

	if (tvnorm != btv->vbi_fmt.tvnorm) {
		__s32 max_end;
		unsigned int i;

		/* As in vbi_buffer_prepare() this imitates the
		   behaviour of earlier driver versions after video
		   standard changes, with default parameters anyway. */

		max_end = (tvnorm->cropcap.bounds.top
			   + tvnorm->cropcap.bounds.height) >> 1;

		frt->fmt.vbi.sampling_rate = tvnorm->Fsc;

		for (i = 0; i < 2; ++i) {
			__s32 new_start;

			new_start = frt->fmt.vbi.start[i] + tvnorm->vbistart[i]
				- btv->vbi_fmt.tvnorm->vbistart[i];

			frt->fmt.vbi.start[i] = min(new_start, max_end - 1);
			frt->fmt.vbi.count[i] =
				min((__s32) frt->fmt.vbi.count[i],
					  max_end - frt->fmt.vbi.start[i]);

			max_end += tvnorm->vbistart[1]
				- tvnorm->vbistart[0];
		}
	}
	return 0;
}

void bttv_vbi_fmt_reset(struct bttv_vbi_fmt *f, unsigned int norm)
{
	const struct bttv_tvnorm *tvnorm;
	unsigned int real_samples_per_line;
	unsigned int real_count;

	tvnorm = &bttv_tvnorms[norm];

	f->fmt.sampling_rate    = tvnorm->Fsc;
	f->fmt.samples_per_line = VBI_BPL;
	f->fmt.sample_format    = V4L2_PIX_FMT_GREY;
	f->fmt.offset           = VBI_OFFSET;
	f->fmt.start[0]		= tvnorm->vbistart[0];
	f->fmt.start[1]		= tvnorm->vbistart[1];
	f->fmt.count[0]		= VBI_DEFLINES;
	f->fmt.count[1]		= VBI_DEFLINES;
	f->fmt.flags            = 0;
	f->fmt.reserved[0]      = 0;
	f->fmt.reserved[1]      = 0;

	/* For compatibility the buffer size must be 2 * VBI_DEFLINES *
	   VBI_BPL regardless of the current video standard. */
	real_samples_per_line   = 1024 + tvnorm->vbipack * 4;
	real_count              = ((tvnorm->cropcap.defrect.top >> 1)
				   - tvnorm->vbistart[0]);

	WARN_ON(real_samples_per_line > VBI_BPL);
	WARN_ON(real_count > VBI_DEFLINES);

	f->tvnorm               = tvnorm;

	/* See bttv_vbi_fmt_set(). */
	f->end                  = tvnorm->vbistart[0] * 2 + 2;
}