On 04/02/2025 at 10:43:20 GMT, "Rabara, Niravkumar L" <niravkumar.l.rabara@xxxxxxxxx> wrote: > 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. I don't see well how you can defer if there is no resource to grab. And if there is a resource to grab, why is it not described anywhere? Thanks, Miquèl
