Hi Laurent, > Subject: Re: [PATCH 1/5] dt-bindings: dma: Document RZ/G2L bindings > > Hi Biju, > > 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. Regards, Biju > > > > > > 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
