RE: [PATCH v2 1/3] mtd: rawnand: cadence: support deferred prob when DMA is not ready

[Rabara, Niravkumar L]

Hi Miquel,

> -----Original Message-----
> From: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
> Sent: Tuesday, 4 February, 2025 5:20 PM
> To: Rabara, Niravkumar L <niravkumar.l.rabara@xxxxxxxxx>
> Cc: Richard Weinberger <richard@xxxxxx>; Vignesh Raghavendra
> <vigneshr@xxxxxx>; linux@xxxxxxxxxxx; Shen Lichuan <shenlichuan@xxxxxxxx>;
> Jinjie Ruan <ruanjinjie@xxxxxxxxxx>; u.kleine-koenig@xxxxxxxxxxxx; linux-
> mtd@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; stable@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v2 1/3] mtd: rawnand: cadence: support deferred prob when
> DMA is not ready
> 
> Hello,
> 
> > My apologies for the confusion.
> > Slave DMA terminology used in cadence nand controller bindings and
> > driver is indeed confusing.
> >
> > To answer your question it is,
> > 1 - External DMA (Generic DMA controller).
> >
> > Nand controller IP do not have embedded DMA controller (2 - peripheral
> DMA).
> >
> > FYR, how external DMA is used.
> > https://elixir.bootlin.com/linux/v6.13.1/source/drivers/mtd/nand/raw/c
> > adence-nand-controller.c#L1962
> 
> In this case we should have a dmas property (and perhaps dma-names), no?
> 
No, I believe.
Cadence NAND controller IP do not have dedicated handshake interface to connect
with DMA controller.
My understanding is dmas (and dma-names) are only used for the dedicated handshake
interface between peripheral and the DMA controller.

Thanks,
Nirav