From: Gerhard Sittig <gsi@xxxxxxx>
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 <gsi@xxxxxxx>
---
.../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 d2ec42d..9929cdc 100644
--- a/drivers/dma/mpc512x_dma.c
+++ b/drivers/dma/mpc512x_dma.c
@@ -48,6 +48,7 @@
#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>
@@ -1013,11 +1014,23 @@ 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;
}
@@ -1026,6 +1039,8 @@ 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);
--
1.7.11.3
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