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?
For the intel,lgm-* DMAs you only call issue_pending() and probably
terminate_all?
Interesting setup ;)
- Péter
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
