On Sat, 14 Mar 2009, Robert Jarzmik wrote:
> All planes were PAGE aligned (ie. 4096 bytes aligned). This
> is not consistent with YUV422 format, which requires Y, U
> and V planes glued together. The new implementation forces
> the alignement on 8 bytes (DMA requirement), which is almost
> always the case (granted by width x height being a multiple
> of 8).
>
> The test cases include tests in both YUV422 and RGB565 :
> - a picture of size 111 x 111 (cross RAM pages example)
> - a picture of size 1023 x 4 in (under 1 RAM page)
> - a picture of size 1024 x 4 in (exactly 1 RAM page)
> - a picture of size 1025 x 4 in (over 1 RAM page)
> - a picture of size 1280 x 1024 (many RAM pages)
>
> Signed-off-by: Robert Jarzmik <[email protected]>
> ---
> drivers/media/video/pxa_camera.c | 150
> +++++++++++++++++++++++++++-----------
> 1 files changed, 108 insertions(+), 42 deletions(-)
>
> diff --git a/drivers/media/video/pxa_camera.c
> b/drivers/media/video/pxa_camera.c
> index 8e5611b..aca5374 100644
> --- a/drivers/media/video/pxa_camera.c
> +++ b/drivers/media/video/pxa_camera.c
> @@ -287,19 +287,63 @@ static void free_buffer(struct videobuf_queue *vq,
> struct pxa_buffer *buf)
> buf->vb.state = VIDEOBUF_NEEDS_INIT;
> }
>
> +static int calculate_dma_sglen(struct scatterlist *sglist, int sglen,
> + int sg_first_ofs, int size)
> +{
> + int i, offset, dma_len, xfer_len;
> + struct scatterlist *sg;
> +
> + offset = sg_first_ofs;
> + for_each_sg(sglist, sg, sglen, i) {
> + dma_len = sg_dma_len(sg);
> +
> + /* PXA27x Developer's Manual 27.4.4.1: round up to 8 bytes */
> + xfer_len = roundup(min(dma_len - offset, size), 8);
> +
> + size = max(0, size - xfer_len);
> + offset = 0;
> + if (size == 0)
> + break;
> + }
> +
> + BUG_ON(size != 0);
> + return i + 1;
> +}
> +
> +/**
> + * pxa_init_dma_channel - init dma descriptors
> + * @pcdev: pxa camera device
> + * @buf: pxa buffer to find pxa dma channel
> + * @dma: dma video buffer
> + * @channel: dma channel (0 => 'Y', 1 => 'U', 2 => 'V')
> + * @cibr: camera read fifo
I would emphasise, that this is a handle to a register, and use the name
from the datasheet, i.e., just write " camera Receive Buffer Register."
> + * @size: bytes to transfer
> + * @sg_first: index of first element of sg_list
This is not an index any more.
> + * @sg_first_ofs: offset in first element of sg_list
> + *
> + * Prepares the pxa dma descriptors to transfer one camera channel.
> + * Beware sg_first and sg_first_ofs are both input and output parameters.
> + *
> + * Returns 0
...or -errno... - do it right straight away instead of correcting in 3/4.
> + */
> static int pxa_init_dma_channel(struct pxa_camera_dev *pcdev,
> struct pxa_buffer *buf,
> struct videobuf_dmabuf *dma, int channel,
> - int sglen, int sg_start, int cibr,
> - unsigned int size)
> + int cibr, int size,
> + struct scatterlist **sg_first, int
> *sg_first_ofs)
> {
> struct pxa_cam_dma *pxa_dma = &buf->dmas[channel];
> - int i;
> + struct scatterlist *sg;
> + int i, offset, sglen;
> + int dma_len = 0, xfer_len = 0;
>
> if (pxa_dma->sg_cpu)
> dma_free_coherent(pcdev->dev, pxa_dma->sg_size,
> pxa_dma->sg_cpu, pxa_dma->sg_dma);
>
> + sglen = calculate_dma_sglen(*sg_first, dma->sglen,
> + *sg_first_ofs, size);
> +
> pxa_dma->sg_size = (sglen + 1) * sizeof(struct pxa_dma_desc);
> pxa_dma->sg_cpu = dma_alloc_coherent(pcdev->dev, pxa_dma->sg_size,
> &pxa_dma->sg_dma, GFP_KERNEL);
> @@ -307,27 +351,53 @@ static int pxa_init_dma_channel(struct pxa_camera_dev
> *pcdev,
> return -ENOMEM;
>
> pxa_dma->sglen = sglen;
> + offset = *sg_first_ofs;
>
> - for (i = 0; i < sglen; i++) {
> - int sg_i = sg_start + i;
> - struct scatterlist *sg = dma->sglist;
> - unsigned int dma_len = sg_dma_len(&sg[sg_i]), xfer_len;
> + dev_dbg(pcdev->dev, "DMA: sg_first=%p, sglen=%d, ofs=%d, dma.desc=%x\n",
> + *sg_first, sglen, *sg_first_ofs, pxa_dma->sg_dma);
>
> - pxa_dma->sg_cpu[i].dsadr = pcdev->res->start + cibr;
> - pxa_dma->sg_cpu[i].dtadr = sg_dma_address(&sg[sg_i]);
> +
> + for_each_sg(*sg_first, sg, sglen, i) {
> + dma_len = sg_dma_len(sg);
>
> /* PXA27x Developer's Manual 27.4.4.1: round up to 8 bytes */
> - xfer_len = (min(dma_len, size) + 7) & ~7;
> + xfer_len = roundup(min(dma_len - offset, size), 8);
>
> + size = max(0, size - xfer_len);
> +
> + pxa_dma->sg_cpu[i].dsadr = pcdev->res->start + cibr;
> + pxa_dma->sg_cpu[i].dtadr = sg_dma_address(sg) + offset;
> pxa_dma->sg_cpu[i].dcmd =
> DCMD_FLOWSRC | DCMD_BURST8 | DCMD_INCTRGADDR | xfer_len;
> - size -= dma_len;
> pxa_dma->sg_cpu[i].ddadr =
> pxa_dma->sg_dma + (i + 1) * sizeof(struct pxa_dma_desc);
> +
> + dev_vdbg(pcdev->dev, "DMA: desc.%08x->@phys=0x%08x, len=%d\n",
> + pxa_dma->sg_dma + i * sizeof(struct pxa_dma_desc),
> + sg_dma_address(sg) + offset, xfer_len);
> + offset = 0;
> +
> + if (size == 0)
> + break;
> }
>
> - pxa_dma->sg_cpu[sglen - 1].ddadr = DDADR_STOP;
> - pxa_dma->sg_cpu[sglen - 1].dcmd |= DCMD_ENDIRQEN;
> + pxa_dma->sg_cpu[sglen].ddadr = DDADR_STOP;
> + pxa_dma->sg_cpu[sglen].dcmd = DCMD_FLOWSRC | DCMD_BURST8 |
> DCMD_ENDIRQEN;
I still do not understand why are you doing this in this patch - not in
the next one.
> +
> + *sg_first_ofs = xfer_len;
> + /*
> + * Handle 1 special case :
> + * - in 3 planes (YUV422P format), we might finish with xfer_len
> + * equal to dma_len (end on PAGE boundary). In this case, the sg
> + * element for next plane should be the next of the last one
better "next after the last?"
> + * used to store the last scatter gather RAM page
> + */
> + if (*sg_first_ofs >= dma_len) {
> + *sg_first_ofs -= dma_len;
> + *sg_first = sg_next(sg);
> + } else {
> + *sg_first = sg;
> + }
Could do a bit simpler:
+ if (xfer_len >= dma_len) {
+ *sg_first_ofs = xfer_len - dma_len;
+ *sg_first = sg_next(sg);
+ } else {
+ *sg_first_ofs = xfer_len;
+ *sg_first = sg;
+ }
>
> return 0;
> }
> @@ -340,9 +410,7 @@ static int pxa_videobuf_prepare(struct videobuf_queue *vq,
> struct pxa_camera_dev *pcdev = ici->priv;
> struct pxa_buffer *buf = container_of(vb, struct pxa_buffer, vb);
> int ret;
> - int sglen_y, sglen_yu = 0, sglen_u = 0, sglen_v = 0;
> int size_y, size_u = 0, size_v = 0;
> -
> dev_dbg(&icd->dev, "%s (vb=0x%p) 0x%08lx %d\n", __func__,
> vb, vb->baddr, vb->bsize);
Please, keep this empty line.
>
> @@ -379,53 +447,51 @@ static int pxa_videobuf_prepare(struct videobuf_queue
> *vq,
> }
>
> if (vb->state == VIDEOBUF_NEEDS_INIT) {
> - unsigned int size = vb->size;
> + int size = vb->size;
> + int next_ofs = 0;
> struct videobuf_dmabuf *dma = videobuf_to_dma(vb);
> + struct scatterlist *sg;
>
> ret = videobuf_iolock(vq, vb, NULL);
> if (ret)
> goto fail;
>
> if (pcdev->channels == 3) {
> - /* FIXME the calculations should be more precise */
> - sglen_y = dma->sglen / 2;
> - sglen_u = sglen_v = dma->sglen / 4 + 1;
> - sglen_yu = sglen_y + sglen_u;
> size_y = size / 2;
> size_u = size_v = size / 4;
> } else {
> - sglen_y = dma->sglen;
> size_y = size;
> }
>
> - /* init DMA for Y channel */
> - ret = pxa_init_dma_channel(pcdev, buf, dma, 0, sglen_y,
> - 0, 0x28, size_y);
> + sg = dma->sglist;
>
> + /* init DMA for Y channel */
> + ret = pxa_init_dma_channel(pcdev, buf, dma, 0, CIBR0, size_y,
> + &sg, &next_ofs);
> if (ret) {
> dev_err(pcdev->dev,
> "DMA initialization for Y/RGB failed\n");
> goto fail;
> }
>
> - if (pcdev->channels == 3) {
> - /* init DMA for U channel */
> - ret = pxa_init_dma_channel(pcdev, buf, dma, 1, sglen_u,
> - sglen_y, 0x30, size_u);
> - if (ret) {
> - dev_err(pcdev->dev,
> - "DMA initialization for U failed\n");
> - goto fail_u;
> - }
> + /* init DMA for U channel */
> + if (size_u)
> + ret = pxa_init_dma_channel(pcdev, buf, dma, 1, CIBR1,
> + size_u, &sg, &next_ofs);
> + if (ret) {
> + dev_err(pcdev->dev,
> + "DMA initialization for U failed\n");
> + goto fail_u;
> + }
>
> - /* init DMA for V channel */
> - ret = pxa_init_dma_channel(pcdev, buf, dma, 2, sglen_v,
> - sglen_yu, 0x38, size_v);
> - if (ret) {
> - dev_err(pcdev->dev,
> - "DMA initialization for V failed\n");
> - goto fail_v;
> - }
> + /* init DMA for V channel */
> + if (size_v)
> + ret = pxa_init_dma_channel(pcdev, buf, dma, 2, CIBR2,
> + size_u, &sg, &next_ofs);
You meant size_v
> + if (ret) {
> + dev_err(pcdev->dev,
> + "DMA initialization for V failed\n");
> + goto fail_v;
> }
>
> vb->state = VIDEOBUF_PREPARED;
> --
> 1.5.6.5
Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
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