Re: [PATCH 6/7] spi/s3c64xx: Add support DMA engine API

From: Chanho Park <parkch98@gmail.com>
To: Kukjin Kim <kgene.kim@samsung.com>
Cc: linux-arm-kernel@lists.infradead.org,
	linux-samsung-soc@vger.kernel.org,
	Vinod Koul <vinod.koul@intel.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Grant Likely <grant.likely@secretlab.ca>,
	Jassi Brar <jassisinghbrar@gmail.com>, Liam Girdwood <lrg@ti.com>,
	Mark Brown <broonie@opensource.wolfsonmicro.com>,
	Boojin Kim <boojin.kim@samsung.com>
Subject: Re: [PATCH 6/7] spi/s3c64xx: Add support DMA engine API
Date: Tue, 5 Jul 2011 17:39:50 +0900	[thread overview]
Message-ID: <CAPTzV16XF5tVJrw0UO+kM9uz+49b3jtCi9QHVm8eDbd8kbueBA@mail.gmail.com> (raw)
In-Reply-To: <1309781915-31549-7-git-send-email-kgene.kim@samsung.com>

>  static int acquire_dma(struct s3c64xx_spi_driver_data *sdd)
>  {
> +#if defined(CONFIG_DMADEV_PL330)
> +       dma_cap_mask_t mask;
> +       dma_cap_zero(mask);
> +       dma_cap_set(DMA_SLAVE, mask);
> +       sdd->rx_chan =
> +               dma_request_channel(mask, rxfilter, (void *)sdd);
> +       if (!sdd->rx_chan) {
> +               dev_err(&sdd->pdev->dev, "cannot get RxDMA\n");
> +               return 0;
> +       }
> +       sdd->tx_chan =
> +               dma_request_channel(mask, txfilter, (void *)sdd);
> +       if (!sdd->tx_chan) {
> +               dev_err(&sdd->pdev->dev, "cannot get TxDMA\n");
> +               return 0;
> +       }
> +#else

When acquiring tx_chan is failed, you must release a rx_chan before
error return.
If not, the rx_chan is always busy because it was allocated in the
previous attempt.

-- 
Best Regards,
Chanho Park