Hi Marek,

Here is my comments.

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.szyprow...@samsung.com>
> Signed-off-by: Kyungmin Park <kyungmin.p...@samsung.com>
> ---
>  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.

> +             .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.

> +     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 ?

> +     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.
Will FBIO_WAITFORVSYNC be added with panning support ?

<snip>

> --
> 1.7.1.569.g6f426
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