diff options
| author | Peter Ujfalusi <peter.ujfalusi@ti.com> | 2015-10-16 09:18:08 +0200 |
|---|---|---|
| committer | Vinod Koul <vinod.koul@intel.com> | 2015-10-27 02:22:45 +0100 |
| commit | 42dbdcc6bf965997c088caff2a8be7f9bf44f701 (patch) | |
| tree | 1a69ce7985f882141835a2edea317eb4d9d22b30 /Documentation | |
| parent | dmaengine: edma: Merge the of parsing functions (diff) | |
| download | linux-42dbdcc6bf965997c088caff2a8be7f9bf44f701.tar.xz linux-42dbdcc6bf965997c088caff2a8be7f9bf44f701.zip | |
dmaengine: ti-dma-crossbar: Add support for crossbar on AM33xx/AM43xx
The DMA event crossbar on AM33xx/AM43xx is different from the one found in
DRA7x family.
Instead of a single event crossbar it has 64 identical mux attached to each
eDMA event line. When the 0 event mux is selected, the default mapped event
is going to be routed to the corresponding eDMA event line. If different
mux is selected, then the selected event is going to be routed to the given
eDMA event.
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/devicetree/bindings/dma/ti-dma-crossbar.txt | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/Documentation/devicetree/bindings/dma/ti-dma-crossbar.txt b/Documentation/devicetree/bindings/dma/ti-dma-crossbar.txt index 63a48928f3a8..b152a75dceae 100644 --- a/Documentation/devicetree/bindings/dma/ti-dma-crossbar.txt +++ b/Documentation/devicetree/bindings/dma/ti-dma-crossbar.txt @@ -2,9 +2,10 @@ Texas Instruments DMA Crossbar (DMA request router) Required properties: - compatible: "ti,dra7-dma-crossbar" for DRA7xx DMA crossbar + "ti,am335x-edma-crossbar" for AM335x and AM437x - reg: Memory map for accessing module -- #dma-cells: Should be set to <1>. - Clients should use the crossbar request number (input) +- #dma-cells: Should be set to to match with the DMA controller's dma-cells + for ti,dra7-dma-crossbar and <3> for ti,am335x-edma-crossbar. - dma-requests: Number of DMA requests the crossbar can receive - dma-masters: phandle pointing to the DMA controller @@ -14,6 +15,15 @@ The DMA controller node need to have the following poroperties: Optional properties: - ti,dma-safe-map: Safe routing value for unused request lines +Notes: +When requesting channel via ti,dra7-dma-crossbar, the DMA clinet must request +the DMA event number as crossbar ID (input to the DMA crossbar). + +For ti,am335x-edma-crossbar: the meaning of parameters of dmas for clients: +dmas = <&edma_xbar 12 0 1>; where <12> is the DMA request number, <0> is the TC +the event should be assigned and <1> is the mux selection for in the crossbar. +When mux 0 is used the DMA channel can be requested directly from edma node. + Example: /* DMA controller */ @@ -47,6 +57,7 @@ uart1: serial@4806a000 { ti,hwmods = "uart1"; clock-frequency = <48000000>; status = "disabled"; + /* Requesting crossbar input 49 and 50 */ dmas = <&sdma_xbar 49>, <&sdma_xbar 50>; dma-names = "tx", "rx"; }; |