Re: [PATCH 4/7] spi: spi-geni-qcom: Add support for GPI dma

From: Lukas Wunner <lukas@wunner.de>
To: Vinod Koul <vkoul@kernel.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>,
	Mark Brown <broonie@kernel.org>, Wolfram Sang <wsa@kernel.org>,
	linux-arm-msm@vger.kernel.org, Andy Gross <agross@kernel.org>,
	Matthias Kaehlcke <mka@chromium.org>,
	Douglas Anderson <dianders@chromium.org>,
	Sumit Semwal <sumit.semwal@linaro.org>,
	Amit Pundir <amit.pundir@linaro.org>,
	linux-spi@vger.kernel.org, linux-i2c@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 4/7] spi: spi-geni-qcom: Add support for GPI dma
Date: Tue, 12 Jan 2021 08:31:52 +0100	[thread overview]
Message-ID: <20210112073152.GA11056@wunner.de> (raw)
In-Reply-To: <20210111151651.1616813-5-vkoul@kernel.org>

On Mon, Jan 11, 2021 at 08:46:48PM +0530, Vinod Koul wrote:
> @@ -328,8 +609,34 @@ static int spi_geni_init(struct spi_geni_master *mas)
>  	spi_tx_cfg &= ~CS_TOGGLE;
>  	writel(spi_tx_cfg, se->base + SE_SPI_TRANS_CFG);
>  
> +	mas->tx = dma_request_slave_channel(mas->dev, "tx");
> +	if (IS_ERR_OR_NULL(mas->tx)) {
> +		dev_err(mas->dev, "Failed to get tx DMA ch %ld", PTR_ERR(mas->tx));
> +		ret = PTR_ERR(mas->tx);
> +		goto out_pm;
> +	} else {
> +		mas->rx = dma_request_slave_channel(mas->dev, "rx");
> +		if (IS_ERR_OR_NULL(mas->rx)) {
> +			dev_err(mas->dev, "Failed to get rx DMA ch %ld", PTR_ERR(mas->rx));
> +			dma_release_channel(mas->tx);
> +			ret = PTR_ERR(mas->rx);
> +			goto out_pm;
> +		}

These channels need to be released in spi_geni_remove().

Also, you may want to fall back to PIO mode if channel allocation fails.

Thanks,

Lukas