Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 54 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/mailbox/fsl,mu.txt b/Documentation/devicetree/bindings/mailbox/fsl,mu.txt
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+NXP i.MX Messaging Unit (MU)
+--------------------------------------------------------------------
+
+The Messaging Unit module enables two processors within the SoC to
+communicate and coordinate by passing messages (e.g. data, status
+and control) through the MU interface. The MU also provides the ability
+for one processor to signal the other processor using interrupts.
+
+Because the MU manages the messaging between processors, the MU uses
+different clocks (from each side of the different peripheral buses).
+Therefore, the MU must synchronize the accesses from one side to the
+other. The MU accomplishes synchronization using two sets of matching
+registers (Processor A-facing, Processor B-facing).
+
+Messaging Unit Device Node:
+=============================
+
+Required properties:
+-------------------
+- compatible :	should be "fsl,<chip>-mu", the supported chips include
+		imx6sx, imx7s, imx8qxp, imx8qm.
+		The "fsl,imx6sx-mu" compatible is seen as generic and should
+		be included together with SoC specific compatible.
+- reg :		Should contain the registers location and length
+- interrupts :	Interrupt number. The interrupt specifier format depends
+		on the interrupt controller parent.
+- #mbox-cells:  Must be 2.
+			  <&phandle type channel>
+			    phandle   : Label name of controller
+			    type      : Channel type
+			    channel   : Channel number
+
+		This MU support 4 type of unidirectional channels, each type
+		has 4 channels. A total of 16 channels. Following types are
+		supported:
+		0 - TX channel with 32bit transmit register and IRQ transmit
+		acknowledgment support.
+		1 - RX channel with 32bit receive register and IRQ support
+		2 - TX doorbell channel. Without own register and no ACK support.
+		3 - RX doorbell channel.
+
+Optional properties:
+-------------------
+- clocks :	phandle to the input clock.
+- fsl,mu-side-b : Should be set for side B MU.
+
+Examples:
+--------
+lsio_mu0: mailbox@5d1b0000 {
+	compatible = "fsl,imx8qxp-mu";
+	reg = <0x0 0x5d1b0000 0x0 0x10000>;
+	interrupts = <GIC_SPI 176 IRQ_TYPE_LEVEL_HIGH>;
+	#mbox-cells = <2>;
+};