Axi timer
Table of Contents
AXI Timer
Introduction
This page gives an overview of Axi Timer Linux driver which is available as part of the Linux distribution.The LogiCORE™ IP AXI Timer/Counter is a 32/ 64-bit timer module that interfaces to the AXI4-Lite interface.
HW IP features
- AXI interface based on the AXI4-Lite specification
- Two programmable interval timers with interrupt, event generation, and event capture capabilities
- Configurable counter width
- One Pulse Width Modulation (PWM) output
- Cascaded operation of timers in generate and capture modes
Kernel Configuration
Existing driver ( https://github.com/Xilinx/linux-xlnx/blob/xlnx_rebase_v5.4_2020.1/arch/microblaze/kernel/timer.c) is tightly coupled with Microblaze processor. By default it would be used as "arch timer" for Microblaze.
Devicetree
axi_timer_1: timer@41c00000 {
clock-frequency = <100000000>;
clocks = <&clk_bus_0>;
compatible = "xlnx,xps-timer-1.00.a";
interrupt-parent = <&axi_intc_1>;
interrupts = <2 2>;
reg = <0x41c00000 0x10000>;
xlnx,count-width = <0x20>;
xlnx,one-timer-only = <0x0>;
}; |
Mainline status
Existing driver https://github.com/Xilinx/linux-xlnx/blob/master/arch/microblaze/kernel/timer.c is in sync with mainline, except changes related to SMP support.
Boot log snippet
/amba_pl/timer@41c00000: irq=2 xilinx_timer_set_mode: shutdown xilinx_timer_set_mode: periodic sched_clock: 32 bits at 100MHz, resolution 10ns, wraps every 42949672950ns |
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