On 04-02-24, 07:59, Andrea della Porta wrote:
> From: Dom Cobley <popcornmix@xxxxxxxxx>
>
> Add a control bit to enable a multi-beat burst on a DMA.
> This improves DMA performance and is required for HDMI audio.
>
> Signed-off-by: Dom Cobley <popcornmix@xxxxxxxxx>
> Signed-off-by: Andrea della Porta <andrea.porta@xxxxxxxx>
> ---
> drivers/dma/bcm2835-dma.c | 28 ++++++++++++++++++++--------
> 1 file changed, 20 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/dma/bcm2835-dma.c b/drivers/dma/bcm2835-dma.c
> index d8d1f9ba2572..a20700a400a2 100644
> --- a/drivers/dma/bcm2835-dma.c
> +++ b/drivers/dma/bcm2835-dma.c
> @@ -156,7 +156,8 @@ struct bcm2835_desc {
> #define BCM2835_DMA_S_WIDTH BIT(9) /* 128bit writes if set */
> #define BCM2835_DMA_S_DREQ BIT(10) /* enable SREQ for source */
> #define BCM2835_DMA_S_IGNORE BIT(11) /* ignore source reads - read 0 */
> -#define BCM2835_DMA_BURST_LENGTH(x) ((x & 15) << 12)
> +#define BCM2835_DMA_BURST_LENGTH(x) (((x) & 15) << 12)
why this changes, sounds like it does not belong here..
> +#define BCM2835_DMA_GET_BURST_LENGTH(x) (((x) >> 12) & 15)
> #define BCM2835_DMA_CS_FLAGS(x) ((x) & (BCM2835_DMA_PRIORITY(15) | \
> BCM2835_DMA_PANIC_PRIORITY(15) | \
> BCM2835_DMA_WAIT_FOR_WRITES | \
> @@ -180,6 +181,11 @@ struct bcm2835_desc {
> #define WIDE_DEST(x) (((x) & BCM2835_DMA_WIDE_DEST) ? \
> BCM2835_DMA_D_WIDTH : 0)
>
> +/* A fake bit to request that the driver requires multi-beat burst */
> +#define BCM2835_DMA_BURST BIT(30)
> +#define BURST_LENGTH(x) (((x) & BCM2835_DMA_BURST) ? \
> + BCM2835_DMA_BURST_LENGTH(3) : 0)
> +
> /* debug register bits */
> #define BCM2835_DMA_DEBUG_LAST_NOT_SET_ERR BIT(0)
> #define BCM2835_DMA_DEBUG_FIFO_ERR BIT(1)
> @@ -282,7 +288,7 @@ struct bcm2835_desc {
> /* the max dma length for different channels */
> #define MAX_DMA40_LEN SZ_1G
>
> -#define BCM2711_DMA40_BURST_LEN(x) ((min(x, 16) - 1) << 8)
> +#define BCM2711_DMA40_BURST_LEN(x) (((x) & 15) << 8)
> #define BCM2711_DMA40_INC BIT(12)
> #define BCM2711_DMA40_SIZE_32 (0 << 13)
> #define BCM2711_DMA40_SIZE_64 (1 << 13)
> @@ -359,12 +365,16 @@ static inline uint32_t to_bcm2711_ti(uint32_t info)
>
> static inline uint32_t to_bcm2711_srci(uint32_t info)
> {
> - return ((info & BCM2835_DMA_S_INC) ? BCM2711_DMA40_INC : 0);
> + return ((info & BCM2835_DMA_S_INC) ? BCM2711_DMA40_INC : 0) |
> + ((info & BCM2835_DMA_S_WIDTH) ? BCM2711_DMA40_SIZE_128 : 0) |
> + BCM2711_DMA40_BURST_LEN(BCM2835_DMA_GET_BURST_LENGTH(info));
> }
>
> static inline uint32_t to_bcm2711_dsti(uint32_t info)
> {
> - return ((info & BCM2835_DMA_D_INC) ? BCM2711_DMA40_INC : 0);
> + return ((info & BCM2835_DMA_D_INC) ? BCM2711_DMA40_INC : 0) |
> + ((info & BCM2835_DMA_D_WIDTH) ? BCM2711_DMA40_SIZE_128 : 0) |
> + BCM2711_DMA40_BURST_LEN(BCM2835_DMA_GET_BURST_LENGTH(info));
> }
>
> static inline uint32_t to_bcm2711_cbaddr(dma_addr_t addr)
> @@ -933,7 +943,8 @@ static struct dma_async_tx_descriptor *bcm2835_dma_prep_dma_memcpy(
> struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
> struct bcm2835_desc *d;
> u32 info = BCM2835_DMA_D_INC | BCM2835_DMA_S_INC |
> - WAIT_RESP(c->dreq) | WIDE_SOURCE(c->dreq) | WIDE_DEST(c->dreq);
> + WAIT_RESP(c->dreq) | WIDE_SOURCE(c->dreq) |
> + WIDE_DEST(c->dreq) | BURST_LENGTH(c->dreq);
> u32 extra = BCM2835_DMA_INT_EN;
> size_t max_len = bcm2835_dma_max_frame_length(c);
> size_t frames;
> @@ -964,8 +975,8 @@ static struct dma_async_tx_descriptor *bcm2835_dma_prep_slave_sg(
> struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
> struct bcm2835_desc *d;
> dma_addr_t src = 0, dst = 0;
> - u32 info = WAIT_RESP(c->dreq) |
> - WIDE_SOURCE(c->dreq) | WIDE_DEST(c->dreq);
> + u32 info = WAIT_RESP(c->dreq) | WIDE_SOURCE(c->dreq) |
> + WIDE_DEST(c->dreq) | BURST_LENGTH(c->dreq);
> u32 extra = BCM2835_DMA_INT_EN;
> size_t frames;
>
> @@ -1017,7 +1028,8 @@ static struct dma_async_tx_descriptor *bcm2835_dma_prep_dma_cyclic(
> struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
> struct bcm2835_desc *d;
> dma_addr_t src, dst;
> - u32 info = WAIT_RESP(c->dreq) | WIDE_SOURCE(c->dreq) | WIDE_DEST(c->dreq);
> + u32 info = WAIT_RESP(c->dreq) | WIDE_SOURCE(c->dreq) |
> + WIDE_DEST(c->dreq) | BURST_LENGTH(c->dreq);
> u32 extra = 0;
> size_t max_len = bcm2835_dma_max_frame_length(c);
> size_t frames;
> --
> 2.41.0
--
~Vinod
