- Last edited 2 years ago ago
Linux Mailbox framework overview
This article gives information about the Linux® mailbox framework. The mailbox framework is involved in interprocessor communication in heterogeneous multicore systems.
Contents
1 Framework purpose[edit]
The mailbox is used in interprocessor communication to exchange messages or signals between the host and the coprocessor cores. The mailbox framework is based on:
- A mailbox controller that is platform dependent:
- It is in charge of configuring and handling IRQ from the IPCC peripheral.
- It provides a generic API to the mailbox client.
- A mailbox client that is in charge of the message to send or receive.
A general presentation of the mailbox framework is available in the Linux mailbox documentation [1].
2 System overview[edit]
2.1 Component description[edit]
- Mailbox controller
- The mailbox controller is the stm32_ipcc. It configures and controls the IPCC peripheral
- Mailbox client
- The user can define his own mailbox client.
- For example, the RPMsg framework uses mailbox for the interprocessor communication.
- In this case the mailbox client is the remoteproc driver that forwards services from/to the RPMsg framework.
2.2 API description[edit]
The APIs are described in the Mailbox client API [2]
3 Configuration[edit]
3.1 Kernel Configuration[edit]
Activate stm32 IPCC mailbox in kernel configuration using the Linux Menuconfig tool: Menuconfig or how to configure kernel
Device drivers --->
-*- Mailbox Hardware Support --->
<*> STM32 IPCC Mailbox
3.2 Device tree configuration[edit]
Please refer to the IPCC device tree configuration.
4 How to use the framework[edit]
The Linux mailbox documentation [1] provides with a very simple example of use.
5 How to trace and debug the framework[edit]
5.1 How to trace[edit]
Dynamic debug traces can be added using the following commands:
echo -n 'file stm32-ipcc.c +p' > /sys/kernel/debug/dynamic_debug/control echo -n 'file mailbox.c +p' > /sys/kernel/debug/dynamic_debug/control
- stm32-ipcc driver: drivers/mailbox/stm32-ipcc.c
6 Source code location[edit]
- framework: drivers/mailbox/mailbox.c
- client interface: include/linux/mailbox_client.h