linux-kernel - Re: [PATCH V1 1/6] arm64: tegra: Configure QSPI clocks and add DMA

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Message-ID:
 <SN7PR12MB67687FB2A524ED45AEEF6C17BFFC2@SN7PR12MB6768.namprd12.prod.outlook.com>
Date: Wed, 12 Feb 2025 14:39:58 +0000
From: Vishwaroop A <va@...dia.com>
To: Thierry Reding <thierry.reding@...il.com>
CC: Jon Hunter <jonathanh@...dia.com>, Sowjanya Komatineni
	<skomatineni@...dia.com>, Laxman Dewangan <ldewangan@...dia.com>,
	"broonie@...nel.org" <broonie@...nel.org>, "linux-spi@...r.kernel.org"
	<linux-spi@...r.kernel.org>, "linux-tegra@...r.kernel.org"
	<linux-tegra@...r.kernel.org>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>, Krishna Yarlagadda <kyarlagadda@...dia.com>,
	Suresh Mangipudi <smangipudi@...dia.com>
Subject: Re: [PATCH V1 1/6] arm64: tegra: Configure QSPI clocks and add DMA



________________________________________
From: Thierry Reding
Sent: Thursday, January 09, 2025 16:10
To: Vishwaroop A
Cc: Jon Hunter; Sowjanya Komatineni; Laxman Dewangan; broonie@...nel.org; linux-spi@...r.kernel.org; linux-tegra@...r.kernel.org; linux-kernel@...r.kernel.org; Krishna Yarlagadda; Suresh Mangipudi
Subject: Re: [PATCH V1 1/6] arm64: tegra: Configure QSPI clocks and add DMA

On Fri, Jan 03, 2025 at 06:04:02AM +0000, Vishwaroop A wrote:
> Set QSPI0_2X_PM to 199.99 MHz and QSPI0_PM to 99.99 MHz using
> PLLC as the parent clock. These frequencies allow Quad IO DT
> reads up to 99.99 MHz, which is the fastest that can be
> achieved considering various PLL and clock divider constraints.
>
> Populate the DMA and IOMMU properties for the Tegra234 QSPI devices to
> enable DMA support.
>
> Change-Id: I1dded904aa8e0f278c89998481e829f1ce474e8c
> Signed-off-by: Vishwaroop A <va@...dia.com>
> ---
>  arch/arm64/boot/dts/nvidia/tegra234.dtsi | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
>
> diff --git a/arch/arm64/boot/dts/nvidia/tegra234.dtsi b/arch/arm64/boot/dts/nvidia/tegra234.dtsi
> index 984c85eab41a..96d0f13390ae 100644
> --- a/arch/arm64/boot/dts/nvidia/tegra234.dtsi
> +++ b/arch/arm64/boot/dts/nvidia/tegra234.dtsi
> @@ -2948,6 +2948,13 @@
>                                <&bpmp TEGRA234_CLK_QSPI0_PM>;
>                       clock-names = "qspi", "qspi_out";
>                       resets = <&bpmp TEGRA234_RESET_QSPI0>;
> +                     assigned-clocks = <&bpmp TEGRA234_CLK_QSPI0_2X_PM>,
> +                                       <&bpmp TEGRA234_CLK_QSPI0_PM>;
> +                     assigned-clock-rates = <199999999 99999999>;
> +                     assigned-clock-parents = <&bpmp TEGRA234_CLK_PLLC>;
> +                     dma-names = "rx", "tx";
> +                     dma-coherent;
> +                     iommus = <&smmu_niso1 TEGRA234_SID_QSPI0>;
>                       status = "disabled";
>               };
>
> @@ -3031,6 +3038,13 @@
>                                <&bpmp TEGRA234_CLK_QSPI1_PM>;
>                       clock-names = "qspi", "qspi_out";
>                       resets = <&bpmp TEGRA234_RESET_QSPI1>;
> +                     assigned-clocks = <&bpmp TEGRA234_CLK_QSPI1_2X_PM>,
> +                                       <&bpmp TEGRA234_CLK_QSPI1_PM>;
> +                     assigned-clock-rates = <199999999 99999999>;
> +                     assigned-clock-parents = <&bpmp TEGRA234_CLK_PLLC>;
> +                     dma-names = "rx", "tx";
> +                     dma-coherent;
> +                     iommus = <&smmu_niso1 TEGRA234_SID_QSPI1>;
>                       status = "disabled";
>               };
>

>> It looks like these are missing the "dmas" properties that go along with "dma-names".
[Vishwaroop A] dmas property is not required as QSPI uses native dma engine. dmas property is used for assigning  the dma channels. In case of QSPI it has own native DMA engine.  

Thanks,
Vishwaroop

Thierry