From fed8b7e366e7c8f81e957ef91aa8f0a38e038c66 Mon Sep 17 00:00:00 2001 From: Mikko Perttunen Date: Wed, 28 Nov 2018 10:54:12 +0100 Subject: dt-bindings: tegra186-hsp: Add shared mailboxes Shared mailboxes are a mechanism to transport data from one processor in the system to another. They are bidirectional links with both a producer and a consumer. Interrupts are used to let the consumer know when data was written to the mailbox by the producer, and to let the producer know when the consumer has read the data from the mailbox. These interrupts are mapped to one or more "shared interrupts". Typically each processor in the system owns one of these shared interrupts. Add documentation to the device tree bindings about how clients can use mailbox specifiers to request a specific shared mailbox and select which direction they drive. Also document how to specify the shared interrupts in addition to the existing doorbell interrupt. Signed-off-by: Mikko Perttunen Acked-by: Jon Hunter Reviewed-by: Rob Herring Acked-by: Thierry Reding Signed-off-by: Thierry Reding Signed-off-by: Jassi Brar --- .../bindings/mailbox/nvidia,tegra186-hsp.txt | 30 ++++++++++++++++++---- 1 file changed, 25 insertions(+), 5 deletions(-) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/mailbox/nvidia,tegra186-hsp.txt b/Documentation/devicetree/bindings/mailbox/nvidia,tegra186-hsp.txt index b99d25fc2f26..ff3eafc5a882 100644 --- a/Documentation/devicetree/bindings/mailbox/nvidia,tegra186-hsp.txt +++ b/Documentation/devicetree/bindings/mailbox/nvidia,tegra186-hsp.txt @@ -15,12 +15,15 @@ Required properties: Array of strings. one of: - "nvidia,tegra186-hsp" + - "nvidia,tegra194-hsp", "nvidia,tegra186-hsp" - reg : Offset and length of the register set for the device. - interrupt-names Array of strings. Contains a list of names for the interrupts described by the interrupt property. May contain the following entries, in any order: - "doorbell" + - "sharedN", where 'N' is a number from zero up to the number of + external interrupts supported by the HSP instance minus one. Users of this binding MUST look up entries in the interrupt property by name, using this interrupt-names property to do so. - interrupts @@ -29,12 +32,29 @@ Required properties: in a matching order. - #mbox-cells : Should be 2. -The mbox specifier of the "mboxes" property in the client node should -contain two data. The first one should be the HSP type and the second -one should be the ID that the client is going to use. Those information -can be found in the following file. +The mbox specifier of the "mboxes" property in the client node should contain +two cells. The first cell determines the HSP type and the second cell is used +to identify the mailbox that the client is going to use. -- . +For doorbells, the second cell specifies the index of the doorbell to use. + +For shared mailboxes, the second cell is composed of two fields: +- bits 31..24: + A bit mask of flags that further specify how the shared mailbox will be + used. Valid flags are: + - bit 31: + Defines the direction of the mailbox. If set, the mailbox will be used + as a producer (i.e. used to send data). If cleared, the mailbox is the + consumer of data sent by a producer. + +- bits 23.. 0: + The index of the shared mailbox to use. The number of available mailboxes + may vary by instance of the HSP block and SoC generation. + +The following file contains definitions that can be used to construct mailbox +specifiers: + + Example: -- cgit v1.2.3-59-g8ed1b