From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andy Shevchenko Subject: Re: [PATCH 2/5] spi: pl022: use generic DMA slave configuration if possible Date: Tue, 29 Jan 2013 09:49:54 +0200 Message-ID: <1359445794.31148.34.camel@smile> References: <1359395857-1235-1-git-send-email-arnd@arndb.de> <1359410300-26113-1-git-send-email-arnd@arndb.de> <1359410300-26113-3-git-send-email-arnd@arndb.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1359410300-26113-3-git-send-email-arnd-r2nGTMty4D4@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: devicetree-discuss-bounces+gldd-devicetree-discuss=m.gmane.org-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org Sender: "devicetree-discuss" To: Arnd Bergmann Cc: Vinod Koul , Viresh Kumar , devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, Mark Brown , spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: devicetree@vger.kernel.org On Mon, 2013-01-28 at 21:58 +0000, Arnd Bergmann wrote: > 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 > Cc: Grant Likely > Cc: Mark Brown > Cc: spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org > Cc: Viresh Kumar > Cc: Andy Shevchenko > Cc: Vinod Koul > Cc: devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org > Cc: linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org > --- > .../devicetree/bindings/spi/spi_pl022.txt | 36 ++++++++++++++++++ > drivers/spi/spi-pl022.c | 43 +++++++++++++++++++++- > 2 files changed, 77 insertions(+), 2 deletions(-) > > --- 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); Where this memory will be freed? In dependence of the answer could you consider to use devm_kmalloc or __get_free_page? > + 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; -- Andy Shevchenko Intel Finland Oy