Messages in this thread | | | Subject | Re: [PATCH v5 2/2] Add Intel LGM soc DMA support. | From | "Reddy, MallikarjunaX" <> | Date | Mon, 31 Aug 2020 16:07:29 +0800 |
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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 >
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