[PATCH 9/9] media: cedrus: Add H264 decoding support

Paul Kocialkowski
2018-07-27T13:56:45Z

Hi,

On Wed, 2018-06-13 at 16:07 +0200, Maxime Ripard wrote:
> Introduce some basic H264 decoding support in cedrus. So far, only the
> baseline profile videos have been tested, and some more advanced features
> used in higher profiles are not even implemented.

Here are two specific comments about things I noticed when going through
the h264 code.

[...]

> @@ -88,12 +101,37 @@ struct sunxi_cedrus_ctx {
> struct work_struct run_work;
> struct list_head src_list;
> struct list_head dst_list;
> +
> + union {
> + struct {
> + void *mv_col_buf;
> + dma_addr_t mv_col_buf_dma;
> + ssize_t mv_col_buf_size;
> + void *neighbor_info_buf;
> + dma_addr_t neighbor_info_buf_dma;

Should be "neighbour" instead of "neighbor" and the same applies to most
variables related to this, as well as the register description.

[...]

> +static int sunxi_cedrus_h264_start(struct sunxi_cedrus_ctx *ctx)
> +{
> + struct sunxi_cedrus_dev *dev = ctx->dev;
> + int ret;
> +
> + ctx->codec.h264.pic_info_buf =
> + dma_alloc_coherent(dev->dev, SUNXI_CEDRUS_PIC_INFO_BUF_SIZE,
> + &ctx->codec.h264.pic_info_buf_dma,
> + GFP_KERNEL);
> + if (!ctx->codec.h264.pic_info_buf)
> + return -ENOMEM;
> +
> + ctx->codec.h264.neighbor_info_buf =
> + dma_alloc_coherent(dev->dev, SUNXI_CEDRUS_NEIGHBOR_INFO_BUF_SIZE,
> + &ctx->codec.h264.neighbor_info_buf_dma,
> + GFP_KERNEL);
> + if (!ctx->codec.h264.neighbor_info_buf) {
> + ret = -ENOMEM;
> + goto err_pic_buf;
> + }

Although this buffer is allocated here, the resulting address is
apparently never written to the appropriate VPU register (0x54).

Perhaps a write to the aforementioned register was lost along the
development process?

Cheers,

Paul

--
Paul Kocialkowski, Bootlin (formerly Free Electrons)
Embedded Linux and kernel engineering
https://bootlin.com
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