[PATCH 2/5] spi: pl022: use generic DMA slave configuration if possible

Andy Shevchenko
2013-01-29T07:49:54Z

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 <arnd@arndb.de>
> Cc: Grant Likely <grant.likely@secretlab.ca>
> Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
> Cc: spi-devel-general at lists.sourceforge.net
> Cc: Viresh Kumar <viresh.kumar@linaro.org>
> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Cc: Vinod Koul <vinod.koul@linux.intel.com>
> Cc: devicetree-discuss at lists.ozlabs.org
> Cc: linux-arm-kernel at lists.infradead.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 <andriy.shevchenko@linux.intel.com>
Intel Finland Oy