Re: [PATCH v4 15/19] dmaengine: ti: k3-udma-v2: New driver for K3 BCDMA_V2

["Péter Ujfalusi" <peter.ujfalusi@gmail.com>]

On 30/01/2026 13:01, Sai Sree Kartheek Adivi wrote:
> Add support for BCDMA_V2.
> 
> The BCDMA_V2 is different than the existing BCDMA supported by the
> k3-udma driver.
> 
> The changes in BCDMA_V2 are:
> - Autopair: There is no longer a need for PSIL pair and AUTOPAIR bit
>   needs to set in the RT_CTL register.
> - Static channel mapping: Each channel is mapped to a single peripheral.
> - Direct IRQs: There is no INT-A and interrupt lines from DMA are
>   directly connected to GIC.
> - Remote side configuration handled by DMA. So no need to write to PEER
>   registers to START / STOP / PAUSE / TEARDOWN.
> 
> Signed-off-by: Sai Sree Kartheek Adivi <s-adivi@ti.com>
> ---
>  drivers/dma/ti/Kconfig            |   16 +-
>  drivers/dma/ti/Makefile           |    1 +
>  drivers/dma/ti/k3-udma-common.c   |   75 +-
>  drivers/dma/ti/k3-udma-v2.c       | 1283 +++++++++++++++++++++++++++++
>  drivers/dma/ti/k3-udma.h          |  117 +--
>  include/linux/soc/ti/k3-ringacc.h |    3 +
>  6 files changed, 1429 insertions(+), 66 deletions(-)
>  create mode 100644 drivers/dma/ti/k3-udma-v2.c
> 
> diff --git a/drivers/dma/ti/Kconfig b/drivers/dma/ti/Kconfig
> index 712e456015459..ada2ea8aca4b0 100644
> --- a/drivers/dma/ti/Kconfig
> +++ b/drivers/dma/ti/Kconfig
> @@ -49,6 +49,18 @@ config TI_K3_UDMA
>  	  Enable support for the TI UDMA (Unified DMA) controller. This
>  	  DMA engine is used in AM65x and j721e.
>  
> +config TI_K3_UDMA_V2
> +	tristate "Texas Instruments K3 UDMA v2 support"
> +	depends on ARCH_K3
> +	select DMA_ENGINE
> +	select DMA_VIRTUAL_CHANNELS
> +	select TI_K3_UDMA_COMMON
> +	select TI_K3_RINGACC
> +	select TI_K3_PSIL
> +        help
> +	  Enable support for the TI UDMA (Unified DMA) v2 controller. This
> +	  DMA engine is used in AM62L.
> +
>  config TI_K3_UDMA_COMMON
>  	tristate
>  	default n
> @@ -56,14 +68,14 @@ config TI_K3_UDMA_COMMON
>  config TI_K3_UDMA_GLUE_LAYER
>  	tristate "Texas Instruments UDMA Glue layer for non DMAengine users"
>  	depends on ARCH_K3 || COMPILE_TEST
> -	depends on TI_K3_UDMA
> +	depends on TI_K3_UDMA || TI_K3_UDMA_V2

At this point the glue layer should not have dependency on UDMA_V2 as it
only receives BCDMA support, which is not used by the glue?

>  	help
>  	  Say y here to support the K3 NAVSS DMA glue interface
>  	  If unsure, say N.
>  
>  config TI_K3_PSIL
>         tristate
> -       default TI_K3_UDMA
> +       default TI_K3_UDMA || TI_K3_UDMA_V2
>  
>  config TI_DMA_CROSSBAR
>  	bool
> diff --git a/drivers/dma/ti/Makefile b/drivers/dma/ti/Makefile
> index 41bfba944dc6c..296aa3421e71b 100644
> --- a/drivers/dma/ti/Makefile
> +++ b/drivers/dma/ti/Makefile
> @@ -3,6 +3,7 @@ obj-$(CONFIG_TI_CPPI41) += cppi41.o
>  obj-$(CONFIG_TI_EDMA) += edma.o
>  obj-$(CONFIG_DMA_OMAP) += omap-dma.o
>  obj-$(CONFIG_TI_K3_UDMA) += k3-udma.o
> +obj-$(CONFIG_TI_K3_UDMA_V2) += k3-udma-v2.o
>  obj-$(CONFIG_TI_K3_UDMA_COMMON) += k3-udma-common.o
>  obj-$(CONFIG_TI_K3_UDMA_GLUE_LAYER) += k3-udma-glue.o
>  k3-psil-lib-objs := k3-psil.o \
> diff --git a/drivers/dma/ti/k3-udma-common.c b/drivers/dma/ti/k3-udma-common.c
> index 0ffc6becc402e..ba0fc048234ac 100644
> --- a/drivers/dma/ti/k3-udma-common.c
> +++ b/drivers/dma/ti/k3-udma-common.c
> @@ -171,8 +171,13 @@ bool udma_is_desc_really_done(struct udma_chan *uc, struct udma_desc *d)
>  	    uc->config.dir != DMA_MEM_TO_DEV || !(uc->config.tx_flags & DMA_PREP_INTERRUPT))
>  		return true;
>  
> -	peer_bcnt = udma_tchanrt_read(uc, UDMA_CHAN_RT_PEER_BCNT_REG);
> -	bcnt = udma_tchanrt_read(uc, UDMA_CHAN_RT_BCNT_REG);
> +	if (uc->ud->match_data->type >= DMA_TYPE_BCDMA_V2) {
> +		peer_bcnt = udma_chanrt_read(uc, UDMA_CHAN_RT_PERIPH_BCNT_REG);
> +		bcnt = udma_chanrt_read(uc, UDMA_CHAN_RT_BCNT_REG);
> +	} else {
> +		peer_bcnt = udma_tchanrt_read(uc, UDMA_CHAN_RT_PEER_BCNT_REG);
> +		bcnt = udma_tchanrt_read(uc, UDMA_CHAN_RT_BCNT_REG);
> +	}
>  
>  	/* Transfer is incomplete, store current residue and time stamp */
>  	if (peer_bcnt < bcnt) {
> @@ -319,6 +324,7 @@ udma_prep_slave_sg_tr(struct udma_chan *uc, struct scatterlist *sgl,
>  	size_t tr_size;
>  	int num_tr = 0;
>  	int tr_idx = 0;
> +	u32 extra_flags = 0;

nitpick: reverse christmas tree order

>  	u64 asel;
>  
>  	/* estimate the number of TRs we will need */
> @@ -342,6 +348,9 @@ udma_prep_slave_sg_tr(struct udma_chan *uc, struct scatterlist *sgl,
>  	else
>  		asel = (u64)uc->config.asel << K3_ADDRESS_ASEL_SHIFT;
>  
> +	if (dir == DMA_MEM_TO_DEV && uc->ud->match_data->type == DMA_TYPE_BCDMA_V2)

I would add the evaluation order in reverse to skip checking direction
for UDMA_V1.

> +		extra_flags = CPPI5_TR_CSF_EOP;
> +
>  	tr_req = d->hwdesc[0].tr_req_base;
>  	for_each_sg(sgl, sgent, sglen, i) {
>  		dma_addr_t sg_addr = sg_dma_address(sgent);
> @@ -358,7 +367,7 @@ udma_prep_slave_sg_tr(struct udma_chan *uc, struct scatterlist *sgl,
>  
>  		cppi5_tr_init(&tr_req[tr_idx].flags, CPPI5_TR_TYPE1, false,
>  			      false, CPPI5_TR_EVENT_SIZE_COMPLETION, 0);
> -		cppi5_tr_csf_set(&tr_req[tr_idx].flags, CPPI5_TR_CSF_SUPR_EVT);
> +		cppi5_tr_csf_set(&tr_req[tr_idx].flags, CPPI5_TR_CSF_SUPR_EVT | extra_flags);
>  
>  		sg_addr |= asel;
>  		tr_req[tr_idx].addr = sg_addr;
> @@ -372,7 +381,7 @@ udma_prep_slave_sg_tr(struct udma_chan *uc, struct scatterlist *sgl,
>  				      false, false,
>  				      CPPI5_TR_EVENT_SIZE_COMPLETION, 0);
>  			cppi5_tr_csf_set(&tr_req[tr_idx].flags,
> -					 CPPI5_TR_CSF_SUPR_EVT);
> +					 CPPI5_TR_CSF_SUPR_EVT | extra_flags);
>  
>  			tr_req[tr_idx].addr = sg_addr + tr0_cnt1 * tr0_cnt0;
>  			tr_req[tr_idx].icnt0 = tr1_cnt0;
> @@ -632,7 +641,8 @@ int udma_configure_statictr(struct udma_chan *uc, struct udma_desc *d,
>  			d->static_tr.bstcnt = d->residue / d->sglen / div;
>  		else
>  			d->static_tr.bstcnt = d->residue / div;
> -	} else if (uc->ud->match_data->type == DMA_TYPE_BCDMA &&
> +	} else if ((uc->ud->match_data->type == DMA_TYPE_BCDMA ||
> +		   uc->ud->match_data->type == DMA_TYPE_BCDMA_V2) &&

Have you thought of adding a version member to struct udma_match_data
and use that instead of distinct different types for BCDMA/PKTDMA?

Here for example you would not need any change as the code is common for
both v1 and v2.

>  		   uc->config.dir == DMA_DEV_TO_MEM &&
>  		   uc->cyclic) {
>  		/*
...

> diff --git a/drivers/dma/ti/k3-udma-v2.c b/drivers/dma/ti/k3-udma-v2.c
> new file mode 100644
> index 0000000000000..af06d25fd598b
> --- /dev/null
> +++ b/drivers/dma/ti/k3-udma-v2.c

...

> +static bool udma_v2_dma_filter_fn(struct dma_chan *chan, void *param)
> +{
> +	struct udma_chan_config *ucc;
> +	struct psil_endpoint_config *ep_config;
> +	struct udma_v2_filter_param *filter_param;
> +	struct udma_chan *uc;
> +	struct udma_dev *ud;

nitpick: reverse christmas tree order
also in few other places.

-- 
Péter