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diff --git a/Documentation/devicetree/bindings/powerpc/fsl/cpm_qe/cpm.txt b/Documentation/devicetree/bindings/powerpc/fsl/cpm_qe/cpm.txt new file mode 100644 index 00000000000..160c752484b --- /dev/null +++ b/Documentation/devicetree/bindings/powerpc/fsl/cpm_qe/cpm.txt | |||
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1 | * Freescale Communications Processor Module | ||
2 | |||
3 | NOTE: This is an interim binding, and will likely change slightly, | ||
4 | as more devices are supported. The QE bindings especially are | ||
5 | incomplete. | ||
6 | |||
7 | * Root CPM node | ||
8 | |||
9 | Properties: | ||
10 | - compatible : "fsl,cpm1", "fsl,cpm2", or "fsl,qe". | ||
11 | - reg : A 48-byte region beginning with CPCR. | ||
12 | |||
13 | Example: | ||
14 | cpm@119c0 { | ||
15 | #address-cells = <1>; | ||
16 | #size-cells = <1>; | ||
17 | #interrupt-cells = <2>; | ||
18 | compatible = "fsl,mpc8272-cpm", "fsl,cpm2"; | ||
19 | reg = <119c0 30>; | ||
20 | } | ||
21 | |||
22 | * Properties common to multiple CPM/QE devices | ||
23 | |||
24 | - fsl,cpm-command : This value is ORed with the opcode and command flag | ||
25 | to specify the device on which a CPM command operates. | ||
26 | |||
27 | - fsl,cpm-brg : Indicates which baud rate generator the device | ||
28 | is associated with. If absent, an unused BRG | ||
29 | should be dynamically allocated. If zero, the | ||
30 | device uses an external clock rather than a BRG. | ||
31 | |||
32 | - reg : Unless otherwise specified, the first resource represents the | ||
33 | scc/fcc/ucc registers, and the second represents the device's | ||
34 | parameter RAM region (if it has one). | ||
35 | |||
36 | * Multi-User RAM (MURAM) | ||
37 | |||
38 | The multi-user/dual-ported RAM is expressed as a bus under the CPM node. | ||
39 | |||
40 | Ranges must be set up subject to the following restrictions: | ||
41 | |||
42 | - Children's reg nodes must be offsets from the start of all muram, even | ||
43 | if the user-data area does not begin at zero. | ||
44 | - If multiple range entries are used, the difference between the parent | ||
45 | address and the child address must be the same in all, so that a single | ||
46 | mapping can cover them all while maintaining the ability to determine | ||
47 | CPM-side offsets with pointer subtraction. It is recommended that | ||
48 | multiple range entries not be used. | ||
49 | - A child address of zero must be translatable, even if no reg resources | ||
50 | contain it. | ||
51 | |||
52 | A child "data" node must exist, compatible with "fsl,cpm-muram-data", to | ||
53 | indicate the portion of muram that is usable by the OS for arbitrary | ||
54 | purposes. The data node may have an arbitrary number of reg resources, | ||
55 | all of which contribute to the allocatable muram pool. | ||
56 | |||
57 | Example, based on mpc8272: | ||
58 | muram@0 { | ||
59 | #address-cells = <1>; | ||
60 | #size-cells = <1>; | ||
61 | ranges = <0 0 10000>; | ||
62 | |||
63 | data@0 { | ||
64 | compatible = "fsl,cpm-muram-data"; | ||
65 | reg = <0 2000 9800 800>; | ||
66 | }; | ||
67 | }; | ||