On Thu, 7 Feb 2013, Albert Wang wrote:
> This patch adds support of 3 frame buffers in DMA-contiguous mode.
>
> In current DMA_CONTIG mode, only 2 frame buffers can be supported.
> Actually, Marvell CCIC can support 2 or 3 frame buffers.
>
> Currently 3 frame buffers mode will be used by default.
> To use 2 frame buffers mode, can do:
> #define MAX_FRAME_BUFS 2
> in mcam-core.h.
>
> Signed-off-by: Albert Wang <twang13@xxxxxxxxxxx>
> Signed-off-by: Libin Yang <lbyang@xxxxxxxxxxx>
> Acked-by: Jonathan Corbet <corbet@xxxxxxx>
> ---
> drivers/media/platform/marvell-ccic/mcam-core.c | 59 +++++++++++++++++------
> drivers/media/platform/marvell-ccic/mcam-core.h | 13 +++++
> 2 files changed, 57 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/media/platform/marvell-ccic/mcam-core.c b/drivers/media/platform/marvell-ccic/mcam-core.c
> index f206e3c..33fce6c 100755
> --- a/drivers/media/platform/marvell-ccic/mcam-core.c
> +++ b/drivers/media/platform/marvell-ccic/mcam-core.c
> @@ -494,13 +494,32 @@ static void mcam_set_contig_buffer(struct mcam_camera *cam, unsigned int frame)
> struct mcam_vb_buffer *buf;
> struct v4l2_pix_format *fmt = &cam->pix_format;
>
> - /*
> - * If there are no available buffers, go into single mode
> - */
> if (list_empty(&cam->buffers)) {
> - buf = cam->vb_bufs[frame ^ 0x1];
> - set_bit(CF_SINGLE_BUFFER, &cam->flags);
> - cam->frame_state.singles++;
> + /*
> + * If there are no available buffers
> + * go into single buffer mode
> + *
> + * If CCIC use Two Buffers mode
> + * will use another remaining frame buffer
> + * frame 0 -> buf 1
> + * frame 1 -> buf 0
> + *
> + * If CCIC use Three Buffers mode
> + * will use the 2rd remaining frame buffer
> + * frame 0 -> buf 2
> + * frame 1 -> buf 0
> + * frame 2 -> buf 1
> + */
> + buf = cam->vb_bufs[(frame + (MAX_FRAME_BUFS - 1))
> + % MAX_FRAME_BUFS];
> + if (cam->frame_state.usebufs == 0)
> + cam->frame_state.usebufs++;
> + else {
> + set_bit(CF_SINGLE_BUFFER, &cam->flags);
> + cam->frame_state.singles++;
> + if (cam->frame_state.usebufs < 2)
> + cam->frame_state.usebufs++;
What is this .usebufs actually supposed to do? AFAICS, it is only used to
decide, whether it should be changed, I don't see it having any effect on
anything else?
> + }
> } else {
> /*
> * OK, we have a buffer we can use.
> @@ -509,15 +528,15 @@ static void mcam_set_contig_buffer(struct mcam_camera *cam, unsigned int frame)
> queue);
> list_del_init(&buf->queue);
> clear_bit(CF_SINGLE_BUFFER, &cam->flags);
> + if (cam->frame_state.usebufs != (3 - MAX_FRAME_BUFS))
> + cam->frame_state.usebufs--;
> }
>
> cam->vb_bufs[frame] = buf;
> - mcam_reg_write(cam, frame == 0 ? REG_Y0BAR : REG_Y1BAR, buf->yuv_p.y);
> + mcam_reg_write(cam, REG_Y0BAR + (frame << 2), buf->yuv_p.y);
> if (mcam_fmt_is_planar(fmt->pixelformat)) {
> - mcam_reg_write(cam, frame == 0 ?
> - REG_U0BAR : REG_U1BAR, buf->yuv_p.u);
> - mcam_reg_write(cam, frame == 0 ?
> - REG_V0BAR : REG_V1BAR, buf->yuv_p.v);
> + mcam_reg_write(cam, REG_U0BAR + (frame << 2), buf->yuv_p.u);
> + mcam_reg_write(cam, REG_V0BAR + (frame << 2), buf->yuv_p.v);
> }
> }
>
> @@ -526,10 +545,14 @@ static void mcam_set_contig_buffer(struct mcam_camera *cam, unsigned int frame)
> */
> static void mcam_ctlr_dma_contig(struct mcam_camera *cam)
> {
> - mcam_reg_set_bit(cam, REG_CTRL1, C1_TWOBUFS);
> - cam->nbufs = 2;
> - mcam_set_contig_buffer(cam, 0);
> - mcam_set_contig_buffer(cam, 1);
> + unsigned int frame;
> +
> + cam->nbufs = MAX_FRAME_BUFS;
> + for (frame = 0; frame < cam->nbufs; frame++)
> + mcam_set_contig_buffer(cam, frame);
> +
> + if (cam->nbufs == 2)
> + mcam_reg_set_bit(cam, REG_CTRL1, C1_TWOBUFS);
> }
>
> /*
> @@ -1068,6 +1091,12 @@ static int mcam_vb_start_streaming(struct vb2_queue *vq, unsigned int count)
> for (frame = 0; frame < cam->nbufs; frame++)
> clear_bit(CF_FRAME_SOF0 + frame, &cam->flags);
>
> + /*
> + * If CCIC use Two Buffers mode, init usebufs == 1
> + * If CCIC use Three Buffers mode, init usebufs == 0
> + */
> + cam->frame_state.usebufs = 3 - MAX_FRAME_BUFS;
> +
> return mcam_read_setup(cam);
> }
>
> diff --git a/drivers/media/platform/marvell-ccic/mcam-core.h b/drivers/media/platform/marvell-ccic/mcam-core.h
> index 0accdbb..6fffa14 100755
> --- a/drivers/media/platform/marvell-ccic/mcam-core.h
> +++ b/drivers/media/platform/marvell-ccic/mcam-core.h
> @@ -44,6 +44,15 @@ enum mcam_state {
> };
> #define MAX_DMA_BUFS 3
>
> +#ifdef MCAM_MODE_DMA_CONTIG
> +/*
> + * CCIC can support at most 3 frame buffers in DMA_CONTIG buffer mode
> + * 2 - Use Two Buffers mode
> + * 3 - Use Three Buffers mode
> + */
> +#define MAX_FRAME_BUFS 3 /* marvell-ccic used Three Buffers mode as default */
> +#endif
> +
> /*
> * Different platforms work best with different buffer modes, so we
> * let the platform pick.
> @@ -82,6 +91,10 @@ struct mcam_frame_state {
> unsigned int frames;
> unsigned int singles;
> unsigned int delivered;
> + /*
> + * Only usebufs == 2 can enter single buffer mode
> + */
> + unsigned int usebufs;
> };
>
> #define NR_MCAM_CLK 3
> --
> 1.7.9.5
>
Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/
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