Hello,
On Friday, April 01, 2011 10:36 AM Jonghun Han wrote:
> On Wednesday, March 30, 2011 4:01 PM Marek Szyprowski wrote:
> >
> > This patch adds generic frame buffer emulator for any video output device
> > that uses videobuf2 framework. This emulator assumes that the driver is
> > capable of working in single-buffering mode and use memory allocator that
> > allows coherent memory mapping.
> >
> > Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
> > Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
> > ---
> > drivers/media/video/Kconfig | 7 +
> > drivers/media/video/Makefile | 1 +
> > drivers/media/video/videobuf2-fb.c | 565
> > ++++++++++++++++++++++++++++++++++++
> > include/media/videobuf2-fb.h | 22 ++
> > 4 files changed, 595 insertions(+), 0 deletions(-) create mode 100644
>
> <snip>
>
> > +static struct fmt_desc fmt_conv_table[] = {
> > + {
> > + .fourcc = V4L2_PIX_FMT_RGB565,
> > + .bits_per_pixel = 16,
> > + .red = { .offset = 11, .length = 5, },
> > + .green = { .offset = 5, .length = 6, },
> > + .blue = { .offset = 0, .length = 5, },
> > + }, {
> > + .fourcc = V4L2_PIX_FMT_RGB555,
> > + .bits_per_pixel = 16,
> > + .red = { .offset = 11, .length = 5, },
> > + .green = { .offset = 5, .length = 5, },
> > + .blue = { .offset = 0, .length = 5, },
> > + }, {
> > + .fourcc = V4L2_PIX_FMT_RGB444,
> > + .bits_per_pixel = 16,
> > + .red = { .offset = 8, .length = 4, },
> > + .green = { .offset = 4, .length = 4, },
> > + .blue = { .offset = 0, .length = 4, },
> > + .transp = { .offset = 12, .length = 4, },
> > + }, {
> > + .fourcc = V4L2_PIX_FMT_BGR32,
> > + .bits_per_pixel = 32,
> > + .red = { .offset = 16, .length = 4, },
>
> red.length should be 8 in case of BGR32.
Right, stupid copy-paste fault.
> > + .green = { .offset = 8, .length = 8, },
> > + .blue = { .offset = 0, .length = 8, },
> > + .transp = { .offset = 24, .length = 8, },
> > + },
> > + /* TODO: add more format descriptors */ };
> > +
> > +/**
> > + * vb2_drv_lock() - a shortcut to call driver specific lock()
> > + * @q: videobuf2 queue
> > + */
> > +static inline void vb2_drv_lock(struct vb2_queue *q) {
> > + q->ops->wait_finish(q);
> > +}
> > +
> > +/**
> > + * vb2_drv_unlock() - a shortcut to call driver specific unlock()
> > + * @q: videobuf2 queue
> > + */
> > +static inline void vb2_drv_unlock(struct vb2_queue *q) {
> > + q->ops->wait_prepare(q);
> > +}
> > +
> > +/**
> > + * vb2_fb_activate() - activate framebuffer emulator
> > + * @info: framebuffer vb2 emulator data
> > + * This function activates framebuffer emulator. The pixel format
> > + * is acquired from video node, memory is allocated and framebuffer
> > + * structures are filled with valid data.
> > + */
> > +static int vb2_fb_activate(struct fb_info *info) {
> > + struct vb2_fb_data *data = info->par;
> > + struct vb2_queue *q = data->q;
> > + struct fb_var_screeninfo *var;
> > + struct v4l2_format fmt;
> > + struct fmt_desc *conv = NULL;
> > + int width, height, fourcc, bpl, size;
> > + int i, ret = 0;
> > + int (*g_fmt)(struct file *file, void *fh, struct v4l2_format *f);
> > +
> > + /*
> > + * Check if streaming api has not been already activated.
> > + */
> > + if (q->streaming || q->num_buffers > 0)
> > + return -EBUSY;
> > +
> > + dprintk(3, "setting up framebuffer\n");
> > +
> > + /*
> > + * Open video node.
> > + */
> > + ret = data->vfd->fops->open(&data->fake_file);
> > + if (ret)
> > + return ret;
> > +
> > + /*
> > + * Get format from the video node.
> > + */
> > + memset(&fmt, 0, sizeof(fmt));
> > + fmt.type = q->type;
> > + if (data->vfd->ioctl_ops->vidioc_g_fmt_vid_out) {
> > + g_fmt = data->vfd->ioctl_ops->vidioc_g_fmt_vid_out;
> > + ret = g_fmt(&data->fake_file, data->fake_file.private_data,
> > &fmt);
> > + if (ret)
> > + goto err;
> > + width = fmt.fmt.pix.width;
> > + height = fmt.fmt.pix.height;
> > + fourcc = fmt.fmt.pix.pixelformat;
> > + bpl = fmt.fmt.pix.bytesperline;
> > + size = fmt.fmt.pix.sizeimage;
> > + } else if (data->vfd->ioctl_ops->vidioc_g_fmt_vid_out_mplane) {
> > + g_fmt = data->vfd->ioctl_ops->vidioc_g_fmt_vid_out_mplane;
> > + ret = g_fmt(&data->fake_file, data->fake_file.private_data,
> > &fmt);
> > + if (ret)
> > + goto err;
> > + width = fmt.fmt.pix_mp.width;
> > + height = fmt.fmt.pix_mp.height;
> > + fourcc = fmt.fmt.pix_mp.pixelformat;
> > + bpl = fmt.fmt.pix_mp.plane_fmt[0].bytesperline;
> > + size = fmt.fmt.pix_mp.plane_fmt[0].sizeimage;
> > + } else {
> > + ret = -EINVAL;
> > + goto err;
> > + }
> > +
> > + dprintk(3, "fb emu: width %d height %d fourcc %08x size %d bpl
> %d\n",
> > + width, height, fourcc, size, bpl);
> > +
> > + /*
> > + * Find format mapping with fourcc returned by g_fmt().
> > + */
> > + for (i = 0; i < ARRAY_SIZE(fmt_conv_table); i++) {
> > + if (fmt_conv_table[i].fourcc == fourcc) {
> > + conv = &fmt_conv_table[i];
> > + break;
> > + }
> > + }
> > +
> > + if (conv == NULL) {
> > + ret = -EBUSY;
> > + goto err;
> > + }
> > +
> > + /*
> > + * Request buffers and use MMAP type to force driver
> > + * to allocate buffers by itself.
> > + */
> > + data->req.count = 1;
> > + data->req.memory = V4L2_MEMORY_MMAP;
> > + data->req.type = q->type;
> > + ret = vb2_reqbufs(q, &data->req);
> > + if (ret)
> > + goto err;
> > +
> > + /*
> > + * Check if plane_count is correct,
> > + * multiplane buffers are not supported.
> > + */
> > + if (q->bufs[0]->num_planes != 1) {
> > + data->req.count = 0;
> > + ret = -EBUSY;
> > + goto err;
> > + }
> > +
> > + /*
> > + * Get kernel address of the buffer.
> > + */
> > + data->vaddr = vb2_plane_vaddr(q->bufs[0], 0);
> > + if (data->vaddr == NULL) {
> > + ret = -EINVAL;
> > + goto err;
> > + }
> > + data->size = size = vb2_plane_size(q->bufs[0], 0);
> > +
> > + /*
> > + * Clear the buffer
> > + */
> > + memset(data->vaddr, 0, size);
> > +
> > + /*
> > + * Setup framebuffer parameters
> > + */
> > + info->screen_base = data->vaddr;
> > + info->screen_size = size;
> > + info->fix.line_length = bpl;
> > + info->fix.smem_len = info->fix.mmio_len = size;
> > +
>
> fix.smem_start is missed.
> Some window systems use it.
fix.smem_start has no meaning for non-contiguous memory allocators. Window system
should call mmap() to get access to framebuffer memory instead of hacking a direct
access with /dev/mem or so. Such mode will be not supported by this emulator.
> > + var = &info->var;
> > + var->xres = var->xres_virtual = var->width = width;
> > + var->yres = var->yres_virtual = var->height = height;
> > + var->bits_per_pixel = conv->bits_per_pixel;
> > + var->red = conv->red;
> > + var->green = conv->green;
> > + var->blue = conv->blue;
> > + var->transp = conv->transp;
> > +
>
> How about setting the fix.xpanstep and fix.ypanstep as 0 explicitly
> if it doesn't support FBIOPAN_DISPLAY ?
Currently fix.xpanstep as well as fix.ypanstep is left as 0. Support for
FBIOPAN_DISPLAY can be added on top of upcoming S_EXTCROP V4L2 ioctl.
> > + return 0;
> > +
> > +err:
> > + data->vfd->fops->release(&data->fake_file);
> > + return ret;
> > +}
> > +
>
> <snip>
>
> > +static struct fb_ops vb2_fb_ops = {
> > + .owner = THIS_MODULE,
> > + .fb_open = vb2_fb_open,
> > + .fb_release = vb2_fb_release,
> > + .fb_mmap = vb2_fb_mmap,
> > + .fb_blank = vb2_fb_blank,
> > + .fb_fillrect = cfb_fillrect,
> > + .fb_copyarea = cfb_copyarea,
> > + .fb_imageblit = cfb_imageblit,
> > +};
> > +
>
> fb_ops.fb_check_var, fb_ops.fb_set_par might be added.
Right, this can be added together with support for full display panning.
> Will FBIO_WAITFORVSYNC be added with panning support ?
This can also be added as a proxy to relevant v4l2 vsync event.
In my first version (which is in fact just a proof-of-concept than a real
patch ready for merging) I just wanted to show that it is possible to have
fb interface built on top of v4l2 video node & vb2. The interface of course
can be extended to support as much features as possible.
Best regards
--
Marek Szyprowski
Samsung Poland R&D Center
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