Hi Biju, On Mon, Jun 14, 2021 at 04:24:38PM +0000, Biju Das wrote: > > On Mon, Jun 14, 2021 at 04:09:04PM +0000, Biju Das wrote: > > > > On Mon, Jun 14, 2021 at 12:54:02PM +0000, Biju Das wrote: > > > > > > On Fri, Jun 11, 2021 at 1:36 PM Biju Das wrote: > > > > > > > Document RZ/G2L DMAC bindings. > > > > > > > > > > > > > > Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx> > > > > > > > Reviewed-by: Lad Prabhakar > > > > > > > <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx> > > > > > > > > > > > > Thanks for your patch! > > > > > > > > > > > > > --- /dev/null > > > > > > > +++ b/Documentation/devicetree/bindings/dma/renesas,rz-dmac.ya > > > > > > > +++ ml > > > > > > > @@ -0,0 +1,132 @@ > > > > > > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) > > > > > > > +%YAML > > > > > > > +1.2 > > > > > > > +--- > > > > > > > +$id: > > > > > > > +https://jpn01.safelinks.protection.outlook.com/?url=http%3A%2 > > > > > > > +F%2F > > > > > > > +devi > > > > > > > +cetree.org%2Fschemas%2Fdma%2Frenesas%2Crz-dmac.yaml%23&da > > > > > > > +ta=0 > > > > > > > +4%7C > > > > > > > +01%7Cbiju.das.jz%40bp.renesas.com%7C4b547e10cbe64b6f4d8508d92 > > > > > > > +f2da > > > > > > > +0c0% > > > > > > > +7C53d82571da1947e49cb4625a166a4a2a%7C0%7C0%7C6375926952868468 > > > > > > > +09%7 > > > > > > > +CUnk > > > > > > > +nown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTi > > > > > > > +I6Ik > > > > > > > +1haW > > > > > > > +wiLCJXVCI6Mn0%3D%7C1000&sdata=5Jh%2FxPaia5ZOY0CrViQCcrNtz > > > > > > > +uDej > > > > > > > +p8wo > > > > > > > +Nrx9iO0ht8%3D&reserved=0 > > > > > > > +$schema: > > > > > > > +https://jpn01.safelinks.protection.outlook.com/?url=http%3A%2 > > > > > > > +F%2F > > > > > > > +devi > > > > > > > +cetree.org%2Fmeta- > > > > schemas%2Fcore.yaml%23&data=04%7C01%7Cbiju.das. > > > > > > > +jz%40bp.renesas.com%7C4b547e10cbe64b6f4d8508d92f2da0c0%7C53d8 > > > > > > > +2571 > > > > > > > +da19 > > > > > > > +47e49cb4625a166a4a2a%7C0%7C0%7C637592695286846809%7CUnknown%7 > > > > > > > +CTWF > > > > > > > +pbGZ > > > > > > > +sb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJX > > > > > > > +VCI6 > > > > > > > +Mn0% > > > > > > > +3D%7C1000&sdata=5qQ1PljM3e4Bn4%2FjdldYUHRBQL3jArJgRIAdLnh > > > > > > > +Jraw > > > > > > > +%3D& > > > > > > > +amp;reserved=0 > > > > > > > > *sigh* > > > > > > > > > > > + > > > > > > > +title: Renesas RZ/G2L DMA Controller > > > > > > > + > > > > > > > +maintainers: > > > > > > > + - Biju Das <biju.das.jz@xxxxxxxxxxxxxx> > > > > > > > + > > > > > > > +allOf: > > > > > > > + - $ref: "dma-controller.yaml#" > > > > > > > + > > > > > > > +properties: > > > > > > > + compatible: > > > > > > > + items: > > > > > > > + - enum: > > > > > > > + - renesas,dmac-r9a07g044 # RZ/G2{L,LC} > > > > > > > > > > > > Please use "renesas,r9a07g044-dmac". > > > > > > > > > > OK. Will change. > > > > > > > > > > > > + - const: renesas,rz-dmac > > > > > > > > > > > > Does this need many changes for RZ/A1H and RZ/A2M? > > > > > > > > > > It will work on both RZ/A1H and RZ/A2M. I have n't tested since I don't have the board. > > > > > There is some difference in MID bit size. Other wise both identical. > > > > > > > > > > > > + renesas,rz-dmac-slavecfg: > > > > > > > + $ref: /schemas/types.yaml#/definitions/uint32-array > > > > > > > + description: | > > > > > > > + DMA configuration for a slave channel. Each channel > > > > > > > + must have an array of > > > > > > > + 3 items as below. > > > > > > > + first item in the array is MID+RID > > > > > > > > > > > > Already in dmas. > > > > > > > > > > > > > + second item in the array is slave src or dst address > > > > > > > > > > > > As pointed out by Rob, already known by the slave driver. > > > > > > > > > > > > > + third item in the array is channel configuration value. > > > > > > > > > > > > What exactly is this? > > > > > > > > What would prevent the DMA client from passing the configuration to > > > > the DMA channel through the DMA engine API, just like it passes the > > > > slave source or destination address ? > > > > > > On RZ/G2L, there is 1 case(SSIF ch2) where MID+RID is same for both tx and rx. > > > The only way we can distinguish it is from channel configuration value. > > > > Are those two different hardware DMA channels ? And configuration values > > change between the two ? > > Yes, REQD is different, apart from this Rx have transfer source and Tx have Transfer destination. > This particular SSIF ch2 is used only for half duplex compared to other SSIF channels. Does this mean there's a single DMA channel, used by two clients, but not at the same time as it only supports half-duplex ? > > > > > > Does the R-Car DMAC have this too? If yes, how does its driver > > > > > > handle it? > > > > > > > > > > On R-CAR DMAC, we have only MID + RID values. Where as here we > > > > > have channel configuration value With different set of parameter > > > > > as mentioned in Table 16.4. > > > > > > > > > > Please see Page 569, Table 16.4 On-Chip Module requests section. > > > > > > > > > > For eg:- as per Rob's suggestion, I have modelled the driver with > > > > > the below entries in ALSA driver for playback/record use case. > > > > > > > > > > dmas = <&dmac 0x255 0x10049c18 CH_CFG(0x1,0x0,0x1,0x0,0x2,0x1,0x1,0x0)>, > > > > > <&dmac 0x256 0x10049c1c > > > > > CH_CFG(0x0,0x0,0x1,0x0,0x2,0x1,0x1,0x0)>; > > > > > dma-names = "tx", "rx"; > > > > > > > > > > Using first parameter, it gets dmac channel. using second and > > > > > third parameter it configures the channel. -- Regards, Laurent Pinchart
