From dc715452e9145156840b09df765ea2ede4851eda Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Mon, 28 Jan 2013 16:24:37 +0000 Subject: spi: pl022: use generic DMA slave configuration if possible With the new OF DMA binding, it is possible to completely avoid the need for platform_data for configuring a DMA channel. In cases where the platform has already been converted, calling dma_request_slave_channel should get all the necessary information from the device tree. Like the patch that converts the dw_dma controller, this is completely untested and is looking for someone to try it out. Signed-off-by: Arnd Bergmann Acked-by: Grant Likely Acked-by: Mark Brown Acked-by: Linus Walleij Cc: spi-devel-general@lists.sourceforge.net Cc: Viresh Kumar Cc: Andy Shevchenko Cc: Vinod Koul Cc: devicetree-discuss@lists.ozlabs.org Cc: linux-arm-kernel@lists.infradead.org --- drivers/spi/spi-pl022.c | 43 +++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 41 insertions(+), 2 deletions(-) (limited to 'drivers/spi') diff --git a/drivers/spi/spi-pl022.c b/drivers/spi/spi-pl022.c index b0fe393c882c..371cc66f1a0e 100644 --- a/drivers/spi/spi-pl022.c +++ b/drivers/spi/spi-pl022.c @@ -1139,6 +1139,35 @@ err_no_rxchan: return -ENODEV; } +static int pl022_dma_autoprobe(struct pl022 *pl022) +{ + struct device *dev = &pl022->adev->dev; + + /* automatically configure DMA channels from platform, normally using DT */ + pl022->dma_rx_channel = dma_request_slave_channel(dev, "rx"); + if (!pl022->dma_rx_channel) + goto err_no_rxchan; + + pl022->dma_tx_channel = dma_request_slave_channel(dev, "tx"); + if (!pl022->dma_tx_channel) + goto err_no_txchan; + + pl022->dummypage = kmalloc(PAGE_SIZE, GFP_KERNEL); + if (!pl022->dummypage) + goto err_no_dummypage; + + return 0; + +err_no_dummypage: + dma_release_channel(pl022->dma_tx_channel); + pl022->dma_tx_channel = NULL; +err_no_txchan: + dma_release_channel(pl022->dma_rx_channel); + pl022->dma_rx_channel = NULL; +err_no_rxchan: + return -ENODEV; +} + static void terminate_dma(struct pl022 *pl022) { struct dma_chan *rxchan = pl022->dma_rx_channel; @@ -1167,6 +1196,11 @@ static inline int configure_dma(struct pl022 *pl022) return -ENODEV; } +static inline int pl022_dma_autoprobe(struct pl022 *pl022) +{ + return 0; +} + static inline int pl022_dma_probe(struct pl022 *pl022) { return 0; @@ -2226,8 +2260,13 @@ static int pl022_probe(struct amba_device *adev, const struct amba_id *id) goto err_no_irq; } - /* Get DMA channels */ - if (platform_info->enable_dma) { + /* Get DMA channels, try autoconfiguration first */ + status = pl022_dma_autoprobe(pl022); + + /* If that failed, use channels from platform_info */ + if (status == 0) + platform_info->enable_dma = 1; + else if (platform_info->enable_dma) { status = pl022_dma_probe(pl022); if (status != 0) platform_info->enable_dma = 0; -- cgit v1.2.3-59-g8ed1b