Axi timer


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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Changelog

2024.1

  • None

2023.2

  • None

2023.1

  • None

2022.2

  • None

2022.1

  • None

2021.2

  • Addressed warnings reported by coverity tool

2021.1

  • None

2020.2

  • None

2020.1

  • Updated driver to support SMP Microblaze systems

2019.2

  • None

2019.1

  • microblaze: Remove architecture heart beat code

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