register the controller for device tree based lookup of DMA channels (non-fatal for backwards compatibility with older device trees), provide the '#dma-cells' property in the shared mpc5121.dtsi file, and introduce a bindings document for the MPC512x DMA controller
Signed-off-by: Gerhard Sittig <g...@denx.de> --- .../devicetree/bindings/dma/mpc512x-dma.txt | 55 ++++++++++++++++++++ arch/powerpc/boot/dts/mpc5121.dtsi | 1 + drivers/dma/mpc512x_dma.c | 21 ++++++-- 3 files changed, 74 insertions(+), 3 deletions(-) create mode 100644 Documentation/devicetree/bindings/dma/mpc512x-dma.txt diff --git a/Documentation/devicetree/bindings/dma/mpc512x-dma.txt b/Documentation/devicetree/bindings/dma/mpc512x-dma.txt new file mode 100644 index 0000000..a4867d5 --- /dev/null +++ b/Documentation/devicetree/bindings/dma/mpc512x-dma.txt @@ -0,0 +1,55 @@ +* Freescale MPC512x DMA Controller + +The DMA controller in the Freescale MPC512x SoC can move blocks of +memory contents between memory and peripherals or memory to memory. + +Refer to the "Generic DMA Controller and DMA request bindings" description +in the dma.txt file for a more detailled discussion of the binding. The +MPC512x DMA engine binding follows the common scheme, but doesn't provide +support for the optional channels and requests counters (those values are +derived from the detected hardware features) and has a fixed client +specifier length of 1 integer cell (the value is the DMA channel, since +the DMA controller uses a fixed assignment of request lines per channel). + + +DMA controller node properties: + +Required properties: +- compatible: should be "fsl,mpc5121-dma" +- reg: address and size of the DMA controller's register set +- interrupts: interrupt spec for the DMA controller + +Optional properties: +- #dma-cells: must be <1>, describes the number of integer cells + needed to specify the 'dmas' property in client nodes, + strongly recommended since common client helper code + uses this property + +Example: + + dma0: dma@14000 { + compatible = "fsl,mpc5121-dma"; + reg = <0x14000 0x1800>; + interrupts = <65 0x8>; + #dma-cells = <1>; + }; + + +Client node properties: + +Required properties: +- dmas: list of DMA specifiers, consisting each of a handle + for the DMA controller and integer cells to specify + the channel used within the DMA controller +- dma-names: list of identifier strings for the DMA specifiers, + client device driver code uses these strings to + have DMA channels looked up at the controller + +Example: + + sdhc@1500 { + compatible = "fsl,mpc5121-sdhc"; + /* ... */ + dmas = <&dma0 30>; + dma-names = "rx-tx"; + }; diff --git a/arch/powerpc/boot/dts/mpc5121.dtsi b/arch/powerpc/boot/dts/mpc5121.dtsi index bd14c00..eb0058f 100644 --- a/arch/powerpc/boot/dts/mpc5121.dtsi +++ b/arch/powerpc/boot/dts/mpc5121.dtsi @@ -390,6 +390,7 @@ compatible = "fsl,mpc5121-dma"; reg = <0x14000 0x1800>; interrupts = <65 0x8>; + #dma-cells = <1>; }; }; diff --git a/drivers/dma/mpc512x_dma.c b/drivers/dma/mpc512x_dma.c index 55e6a87..84fd07b 100644 --- a/drivers/dma/mpc512x_dma.c +++ b/drivers/dma/mpc512x_dma.c @@ -36,6 +36,7 @@ #include <linux/io.h> #include <linux/slab.h> #include <linux/of_device.h> +#include <linux/of_dma.h> #include <linux/of_platform.h> #include <linux/random.h> @@ -959,11 +960,23 @@ static int mpc_dma_probe(struct platform_device *op) /* Register DMA engine */ dev_set_drvdata(dev, mdma); retval = dma_async_device_register(dma); - if (retval) { - devm_free_irq(dev, mdma->irq, mdma); - irq_dispose_mapping(mdma->irq); + if (retval) + goto out_irq; + + /* register with OF helpers for DMA lookups (nonfatal) */ + if (dev->of_node) { + retval = of_dma_controller_register(dev->of_node, + of_dma_xlate_by_chan_id, + mdma); + if (retval) + dev_warn(dev, "could not register for OF lookup\n"); } + return 0; + +out_irq: + devm_free_irq(dev, mdma->irq, mdma); + irq_dispose_mapping(mdma->irq); return retval; } @@ -972,6 +985,8 @@ static int mpc_dma_remove(struct platform_device *op) struct device *dev = &op->dev; struct mpc_dma *mdma = dev_get_drvdata(dev); + if (dev->of_node) + of_dma_controller_free(dev->of_node); dma_async_device_unregister(&mdma->dma); devm_free_irq(dev, mdma->irq, mdma); irq_dispose_mapping(mdma->irq); -- 1.7.10.4 _______________________________________________ devicetree-discuss mailing list devicetree-discuss@lists.ozlabs.org https://lists.ozlabs.org/listinfo/devicetree-discuss