72 lines
2.4 KiB
Plaintext
72 lines
2.4 KiB
Plaintext
Generic hwlock bindings
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=======================
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Generic bindings that are common to all the hwlock platform specific driver
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implementations.
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Please also look through the individual platform specific hwlock binding
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documentations for identifying any additional properties specific to that
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platform.
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hwlock providers:
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=================
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Required properties:
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- #hwlock-cells: Specifies the number of cells needed to represent a
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specific lock. Shall be 1 or 2 (see hwlocks below).
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hwlock users:
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=============
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Consumers that require specific hwlock(s) should specify them using the
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property "hwlocks", and an optional "hwlock-names" property.
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Required properties:
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- hwlocks: List of phandle to a hwlock provider node and an
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associated hwlock args specifier as indicated by
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#hwlock-cells. The list can have just a single hwlock
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or multiple hwlocks, with each hwlock represented by
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a phandle and a corresponding args specifier.
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If #hwlock-cells is 1, all of the locks are exclusive
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(cannot be used by several users).
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If #hwlock-cells is 2, the value of the second cell
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defines whether the lock is for exclusive usage (0) or
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shared (1) i.e. can be used by several users.
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Optional properties:
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- hwlock-names: List of hwlock name strings defined in the same order
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as the hwlocks, with one name per hwlock. Consumers can
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use the hwlock-names to match and get a specific hwlock.
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1. Example of a node using a single specific hwlock:
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The following example has a node requesting a hwlock in the bank defined by
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the node hwlock1. hwlock1 is a hwlock provider with an argument specifier
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of length 1.
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node {
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...
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hwlocks = <&hwlock1 2>;
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...
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};
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2. Example of nodes using multiple and shared specific hwlocks:
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The following example has a nodeA requesting two hwlocks:
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- an exclusive one (#hwlock-cells = 1) within the hwlock device node 'hwlock1'
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- a shared one (#hwlock-cells = 2, second cell = 1) within the hwlock device
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node 'hwlock2'.
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The shared lock is also be used by nodeB.
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nodeA {
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...
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hwlocks = <&hwlock1 2>, <&hwlock2 0 1>;
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...
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};
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nodeB {
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...
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hwlocks = <&hwlock2 0 1>;
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...
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}; |