[PATCH 1/3] dt-bindings: Add a binding for the sunxi message box
samuel at sholland.org
Wed Feb 28 09:52:05 PST 2018
On 02/28/18 02:28, Maxime Ripard wrote:
> On Tue, Feb 27, 2018 at 08:27:12PM -0600, Samuel Holland wrote:
>> This mailbox hardware is present in several Allwinner sun8i and sun50i
>> SoCs. Add a device tree binding for it.
>> Signed-off-by: Samuel Holland <samuel at sholland.org>
>> .../devicetree/bindings/mailbox/sunxi-msgbox.txt | 40 ++++++++++++++++++++++
>> 1 file changed, 40 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/mailbox/sunxi-msgbox.txt
>> diff --git a/Documentation/devicetree/bindings/mailbox/sunxi-msgbox.txt b/Documentation/devicetree/bindings/mailbox/sunxi-msgbox.txt
>> new file mode 100644
>> index 000000000000..3b3ed7f870a0
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/mailbox/sunxi-msgbox.txt
>> @@ -0,0 +1,40 @@
>> +Allwinner sunxi Message Box
>> +The hardware message box on sunxi SoCs is a two-user mailbox controller
>> +containing 8 unidirectional FIFOs bonded into 4 bidirectional mailbox channels.
>> +An interrupt is raised for received messages, but software must poll to know
>> +when a transmitted message has been acknowledged by the remote user.
>> +Refer to ./mailbox.txt for generic information about mailbox device-tree
>> +Mailbox Device Node:
>> +Required properties:
>> +- compatible: Must be "allwinner,sunxi-msgbox".
> The IP change quite often in the Allwinner SoCs, so it would be better
> to use a more specific compatible there. IIRC that IP was introduced
> with the A31, so what about sun6i-a31-msgbox?
Ok, I will do this for v2, following Andre's suggestion. (I knew the AR100 was
introduced with the A31, but I couldn't find any reference to the msgbox in the
>> +- reg: Contains the mailbox register address range (base
>> + address and length).
>> +- clocks: phandle for the clock controller and specifier.
>> +- clock-names: Must be "bus".
>> +- resets: phandle for the reset controller and specifier.
>> +- reset-names: Must be "bus".
>> +- interrupts: Contains interrupt information for the mailbox.
>> +- #mbox-cells Must be 2 - the indexes of the transmit and receive
>> + channels, respectively.
> That would prevent any unidirectional communication, wouldn't it?
> Other mailboxes driver seem to have two mbox channels, one for each
> direction, which also seem to mimic our DMA bindings (where we are in
> pretty much the same situation).
I've responded to Jassi's comment about the same issue on patch 3.
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