4 The OMAP mailbox hardware facilitates communication between different processors
5 using a queued mailbox interrupt mechanism. The IP block is external to the
6 various processor subsystems and is connected on an interconnect bus. The
7 communication is achieved through a set of registers for message storage and
8 interrupt configuration registers.
10 Each mailbox IP block has a certain number of h/w fifo queues and output
11 interrupt lines. An output interrupt line is routed to an interrupt controller
12 within a processor subsystem, and there can be more than one line going to a
13 specific processor's interrupt controller. The interrupt line connections are
14 fixed for an instance and are dictated by the IP integration into the SoC
15 (excluding the SoCs that have a Interrupt Crossbar IP). Each interrupt line is
16 programmable through a set of interrupt configuration registers, and have a rx
17 and tx interrupt source per h/w fifo. Communication between different processors
18 is achieved through the appropriate programming of the rx and tx interrupt
19 sources on the appropriate interrupt lines.
21 The number of h/w fifo queues and interrupt lines dictate the usable registers.
22 All the current OMAP SoCs except for the newest DRA7xx SoC has a single IP
23 instance. DRA7xx has multiple instances with different number of h/w fifo queues
24 and interrupt lines between different instances. The interrupt lines can also be
25 routed to different processor sub-systems on DRA7xx as they are routed through
26 the Crossbar, a kind of interrupt router/multiplexer.
30 A Mailbox device node is used to represent a Mailbox IP instance within a SoC.
31 The sub-mailboxes are represented as child nodes of this parent node.
35 - compatible: Should be one of the following,
36 "ti,omap2-mailbox" for OMAP2420, OMAP2430 SoCs
37 "ti,omap3-mailbox" for OMAP3430, OMAP3630 SoCs
38 "ti,omap4-mailbox" for OMAP44xx, OMAP54xx, AM33xx,
39 AM43xx and DRA7xx SoCs
40 - reg: Contains the mailbox register address range (base
42 - interrupts: Contains the interrupt information for the mailbox
43 device. The format is dependent on which interrupt
44 controller the OMAP device uses
45 - ti,hwmods: Name of the hwmod associated with the mailbox
46 - ti,mbox-num-users: Number of targets (processor devices) that the mailbox
48 - ti,mbox-num-fifos: Number of h/w fifo queues within the mailbox IP block
52 A child node is used for representing the actual sub-mailbox device that is
53 used for the communication between the host processor and a remote processor.
54 Each child node should have a unique node name across all the different
59 - ti,mbox-tx: sub-mailbox descriptor property defining a Tx fifo
60 - ti,mbox-rx: sub-mailbox descriptor property defining a Rx fifo
62 Sub-mailbox Descriptor Data
63 ---------------------------
64 Each of the above ti,mbox-tx and ti,mbox-rx properties should have 3 cells of
65 data that represent the following:
66 Cell #1 (fifo_id) - mailbox fifo id used either for transmitting
67 (ti,mbox-tx) or for receiving (ti,mbox-rx)
68 Cell #2 (irq_id) - irq identifier index number to use from the parent's
69 interrupts data. Should be 0 for most of the cases, a
70 positive index value is seen only on mailboxes that have
71 multiple interrupt lines connected to the MPU processor.
72 Cell #3 (usr_id) - mailbox user id for identifying the interrupt line
73 associated with generating a tx/rx fifo interrupt.
79 mailbox: mailbox@4a0f4000 {
80 compatible = "ti,omap4-mailbox";
81 reg = <0x4a0f4000 0x200>;
82 interrupts = <GIC_SPI 26 IRQ_TYPE_LEVEL_HIGH>;
83 ti,hwmods = "mailbox";
84 ti,mbox-num-users = <3>;
85 ti,mbox-num-fifos = <8>;
97 mailbox: mailbox@480C8000 {
98 compatible = "ti,omap4-mailbox";
99 reg = <0x480C8000 0x200>;
101 ti,hwmods = "mailbox";
102 ti,mbox-num-users = <4>;
103 ti,mbox-num-fifos = <8>;
104 mbox_wkupm3: wkup_m3 {
105 ti,mbox-tx = <0 0 0>;
106 ti,mbox-rx = <0 0 3>;