On 8/28/2020 7:17 PM, Peter Ujfalusi wrote:
Hi,
On 27/08/2020 17.41, Reddy, MallikarjunaX wrote:
+
+ dma_dev->device_alloc_chan_resources =
+ d->inst->ops->device_alloc_chan_resources;
+ dma_dev->device_free_chan_resources =
+ d->inst->ops->device_free_chan_resources;
+ dma_dev->device_terminate_all =
d->inst->ops->device_terminate_all;
+ dma_dev->device_issue_pending =
d->inst->ops->device_issue_pending;
+ dma_dev->device_tx_status = d->inst->ops->device_tx_status;
+ dma_dev->device_resume = d->inst->ops->device_resume;
+ dma_dev->device_pause = d->inst->ops->device_pause;
+ dma_dev->device_config = d->inst->ops->device_config;
+ dma_dev->device_prep_slave_sg =
d->inst->ops->device_prep_slave_sg;
+ dma_dev->device_synchronize = d->inst->ops->device_synchronize;
+
+ if (d->ver == DMA_VER22) {
+ dma_dev->src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
+ dma_dev->dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
+ dma_dev->directions = BIT(DMA_MEM_TO_DEV) |
+ BIT(DMA_DEV_TO_MEM);
+ dma_dev->residue_granularity =
+ DMA_RESIDUE_GRANULARITY_DESCRIPTOR;
+ }
So, if version is != DMA_VER22, then you don't support any direction?
Why register the DMA device if it can not do any transfer?
Only dma0 instance (intel,lgm-cdma) is used as a general purpose slave
DMA. we set both control and datapath here.
Other instances we set only control path. data path is taken care by dma
client(GSWIP).
How the client (GSWIP) can request a channel from intel,lgm-* ? Don't
you need some capabilities for the DMA device so core can sort out the
request?
client request channel by name, dma_request_slave_channel(dev, name);
clients should use dma_request_chan(dev, name);
If the channel can be requested via DT or ACPI then we don't check the
capabilities at all, so yes, that could work.
Only thing needs to do is get the channel, set the descriptor and just
on the channel.
How do you 'on' the channel?
we on the channel in issue_pending.
Right.
Basically you only prep_slave_sg/single for the DMA_VER22? Or do you
that for the others w/o direction support?
Yes. prep_slave_sg/single only for the DMA_VER22.
For the intel,lgm-* DMAs you only call issue_pending() and probably
terminate_all?
Yes, correct.
Interesting setup ;)
- Péter
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
