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authorArnd Bergmann <arnd@arndb.de>2013-02-27 21:36:03 +0000
committerVinod Koul <vinod.koul@intel.com>2013-02-28 09:53:21 +0530
commitf9c6a655a94042f94c0adb30d07d93cfd8915e95 (patch)
tree527fa9aa65510c3ad96e4bb93fbdb6abd46b9f37 /Documentation
parentdmaengine: add dma_request_slave_channel_compat() (diff)
downloadlinux-dev-f9c6a655a94042f94c0adb30d07d93cfd8915e95.tar.xz
linux-dev-f9c6a655a94042f94c0adb30d07d93cfd8915e95.zip
dmaengine: dw_dmac: move to generic DMA binding
The original device tree binding for this driver, from Viresh Kumar unfortunately conflicted with the generic DMA binding, and did not allow to completely seperate slave device configuration from the controller. This is an attempt to replace it with an implementation of the generic binding, but it is currently completely untested, because I do not have any hardware with this particular controller. The patch applies on top of the slave-dma tree, which contains both the base support for the generic DMA binding, as well as the earlier attempt from Viresh. Both of these are currently not merged upstream however. This version incorporates feedback from Viresh Kumar, Andy Shevchenko and Russell King. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Vinod Koul <vinod.koul@linux.intel.com> Cc: devicetree-discuss@lists.ozlabs.org Cc: linux-arm-kernel@lists.infradead.org Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/devicetree/bindings/dma/snps-dma.txt70
1 files changed, 36 insertions, 34 deletions
diff --git a/Documentation/devicetree/bindings/dma/snps-dma.txt b/Documentation/devicetree/bindings/dma/snps-dma.txt
index 5bb3dfb6f1d8..d58675ea1abf 100644
--- a/Documentation/devicetree/bindings/dma/snps-dma.txt
+++ b/Documentation/devicetree/bindings/dma/snps-dma.txt
@@ -3,59 +3,61 @@
Required properties:
- compatible: "snps,dma-spear1340"
- reg: Address range of the DMAC registers
-- interrupt-parent: Should be the phandle for the interrupt controller
- that services interrupts for this device
- interrupt: Should contain the DMAC interrupt number
-- nr_channels: Number of channels supported by hardware
-- is_private: The device channels should be marked as private and not for by the
- general purpose DMA channel allocator. False if not passed.
+- dma-channels: Number of channels supported by hardware
+- dma-requests: Number of DMA request lines supported, up to 16
+- dma-masters: Number of AHB masters supported by the controller
+- #dma-cells: must be <3>
- chan_allocation_order: order of allocation of channel, 0 (default): ascending,
1: descending
- chan_priority: priority of channels. 0 (default): increase from chan 0->n, 1:
increase from chan n->0
- block_size: Maximum block size supported by the controller
-- nr_masters: Number of AHB masters supported by the controller
- data_width: Maximum data width supported by hardware per AHB master
(0 - 8bits, 1 - 16bits, ..., 5 - 256bits)
-- slave_info:
- - bus_id: name of this device channel, not just a device name since
- devices may have more than one channel e.g. "foo_tx". For using the
- dw_generic_filter(), slave drivers must pass exactly this string as
- param to filter function.
- - cfg_hi: Platform-specific initializer for the CFG_HI register
- - cfg_lo: Platform-specific initializer for the CFG_LO register
- - src_master: src master for transfers on allocated channel.
- - dst_master: dest master for transfers on allocated channel.
+
+
+Optional properties:
+- interrupt-parent: Should be the phandle for the interrupt controller
+ that services interrupts for this device
+- is_private: The device channels should be marked as private and not for by the
+ general purpose DMA channel allocator. False if not passed.
Example:
- dma@fc000000 {
+ dmahost: dma@fc000000 {
compatible = "snps,dma-spear1340";
reg = <0xfc000000 0x1000>;
interrupt-parent = <&vic1>;
interrupts = <12>;
- nr_channels = <8>;
+ dma-channels = <8>;
+ dma-requests = <16>;
+ dma-masters = <2>;
+ #dma-cells = <3>;
chan_allocation_order = <1>;
chan_priority = <1>;
block_size = <0xfff>;
- nr_masters = <2>;
data_width = <3 3 0 0>;
+ };
- slave_info {
- uart0-tx {
- bus_id = "uart0-tx";
- cfg_hi = <0x4000>; /* 0x8 << 11 */
- cfg_lo = <0>;
- src_master = <0>;
- dst_master = <1>;
- };
- spi0-tx {
- bus_id = "spi0-tx";
- cfg_hi = <0x2000>; /* 0x4 << 11 */
- cfg_lo = <0>;
- src_master = <0>;
- dst_master = <0>;
- };
- };
+DMA clients connected to the Designware DMA controller must use the format
+described in the dma.txt file, using a four-cell specifier for each channel.
+The four cells in order are:
+
+1. A phandle pointing to the DMA controller
+2. The DMA request line number
+3. Source master for transfers on allocated channel
+4. Destination master for transfers on allocated channel
+
+Example:
+
+ serial@e0000000 {
+ compatible = "arm,pl011", "arm,primecell";
+ reg = <0xe0000000 0x1000>;
+ interrupts = <0 35 0x4>;
+ status = "disabled";
+ dmas = <&dmahost 12 0 1>,
+ <&dmahost 13 0 1 0>;
+ dma-names = "rx", "rx";
};