Re: [PATCH v11 2/2] mtd: rawnand: Add Loongson-1 NAND Controller Driver

From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Keguang Zhang <keguang.zhang@gmail.com>
Cc: Keguang Zhang via B4 Relay
	<devnull+keguang.zhang.gmail.com@kernel.org>,
	Richard Weinberger <richard@nod.at>,
	 Vignesh Raghavendra <vigneshr@ti.com>,
	 Rob Herring <robh@kernel.org>,
	 Krzysztof Kozlowski <krzk+dt@kernel.org>,
	 Conor Dooley <conor+dt@kernel.org>,
	linux-mtd@lists.infradead.org,  linux-kernel@vger.kernel.org,
	devicetree@vger.kernel.org,  linux-media@vger.kernel.org
Subject: Re: [PATCH v11 2/2] mtd: rawnand: Add Loongson-1 NAND Controller Driver
Date: Mon, 20 Jan 2025 13:54:17 +0100	[thread overview]
Message-ID: <8734hdsl1i.fsf@bootlin.com> (raw)
In-Reply-To: <CAJhJPsU1eFJ_R1-emENs8T5rrKXUKjvk-cQx9RT2ztTvmOTZug@mail.gmail.com> (Keguang Zhang's message of "Mon, 20 Jan 2025 19:08:55 +0800")

>> IIUC, yes and no. It is the remapped address of the physical address you
>> want to reach, not the physical address itself. The type is dma_addr_t
>> and not phys_addr_t and you can get a dma address out of a physical
>> address with a call to dma_map_resource(). The numerical value might be
>> the same if there is no IO-MMU involved, but the good practice is to
>> remap anyway.
>
> Got it. I will keep dma_map_resource() as it is, which is called in
> ls1x_nand_probe().
>
> +       res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "nand-dma");
> +       host->dma_base = dma_map_resource(dev, res->start, resource_size(res),
> +                                         DMA_BIDIRECTIONAL, 0);
> +       if (dma_mapping_error(dev, host->dma_base))
> +               return -ENXIO;

Looks correct.

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