LXR uboot/arch/arm/mach-zynq/timer.c

   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * Copyright (C) 2017 Weidmüller Interface GmbH & Co. KG
   4 * Stefan Herbrechtsmeier <stefan.herbrechtsmeier@weidmueller.com>
   5 *
   6 * Copyright (C) 2012 Michal Simek <monstr@monstr.eu>
   7 * Copyright (C) 2011-2017 Xilinx, Inc. All rights reserved.
   8 *
   9 * (C) Copyright 2008
  10 * Guennadi Liakhovetki, DENX Software Engineering, <lg@denx.de>
  11 *
  12 * (C) Copyright 2004
  13 * Philippe Robin, ARM Ltd. <philippe.robin@arm.com>
  14 *
  15 * (C) Copyright 2002-2004
  16 * Gary Jennejohn, DENX Software Engineering, <gj@denx.de>
  17 *
  18 * (C) Copyright 2003
  19 * Texas Instruments <www.ti.com>
  20 *
  21 * (C) Copyright 2002
  22 * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
  23 * Marius Groeger <mgroeger@sysgo.de>
  24 *
  25 * (C) Copyright 2002
  26 * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
  27 * Alex Zuepke <azu@sysgo.de>
  28 */
  29
  30#include <clk.h>
  31#include <common.h>
  32#include <div64.h>
  33#include <dm.h>
  34#include <init.h>
  35#include <time.h>
  36#include <malloc.h>
  37#include <asm/global_data.h>
  38#include <asm/io.h>
  39#include <asm/arch/hardware.h>
  40#include <asm/arch/clk.h>
  41
  42DECLARE_GLOBAL_DATA_PTR;
  43
  44struct scu_timer {
  45        u32 load; /* Timer Load Register */
  46        u32 counter; /* Timer Counter Register */
  47        u32 control; /* Timer Control Register */
  48};
  49
  50static struct scu_timer *timer_base =
  51                              (struct scu_timer *)ZYNQ_SCUTIMER_BASEADDR;
  52
  53#define SCUTIMER_CONTROL_PRESCALER_MASK 0x0000FF00 /* Prescaler */
  54#define SCUTIMER_CONTROL_PRESCALER_SHIFT        8
  55#define SCUTIMER_CONTROL_AUTO_RELOAD_MASK       0x00000002 /* Auto-reload */
  56#define SCUTIMER_CONTROL_ENABLE_MASK            0x00000001 /* Timer enable */
  57
  58#define TIMER_LOAD_VAL 0xFFFFFFFF
  59#define TIMER_PRESCALE 255
  60
  61int timer_init(void)
  62{
  63        const u32 emask = SCUTIMER_CONTROL_AUTO_RELOAD_MASK |
  64                        (TIMER_PRESCALE << SCUTIMER_CONTROL_PRESCALER_SHIFT) |
  65                        SCUTIMER_CONTROL_ENABLE_MASK;
  66
  67        struct udevice *dev;
  68        struct clk clk;
  69        int ret;
  70
  71        ret = uclass_get_device_by_driver(UCLASS_CLK,
  72                DM_DRIVER_GET(zynq_clk), &dev);
  73        if (ret)
  74                return ret;
  75
  76        clk.id = cpu_6or4x_clk;
  77        ret = clk_request(dev, &clk);
  78        if (ret < 0)
  79                return ret;
  80
  81        gd->cpu_clk = clk_get_rate(&clk);
  82
  83        clk_free(&clk);
  84
  85        gd->arch.timer_rate_hz = (gd->cpu_clk / 2) / (TIMER_PRESCALE + 1);
  86
  87        /* Load the timer counter register */
  88        writel(0xFFFFFFFF, &timer_base->load);
  89
  90        /*
  91         * Start the A9Timer device
  92         * Enable Auto reload mode, Clear prescaler control bits
  93         * Set prescaler value, Enable the decrementer
  94         */
  95        clrsetbits_le32(&timer_base->control, SCUTIMER_CONTROL_PRESCALER_MASK,
  96                                                                emask);
  97
  98        /* Reset time */
  99        gd->arch.lastinc = readl(&timer_base->counter) /
 100                                (gd->arch.timer_rate_hz / CONFIG_SYS_HZ);
 101        gd->arch.tbl = 0;
 102
 103        return 0;
 104}
 105
 106/*
 107 * This function is derived from PowerPC code (timebase clock frequency).
 108 * On ARM it returns the number of timer ticks per second.
 109 */
 110ulong get_tbclk(void)
 111{
 112        return gd->arch.timer_rate_hz;
 113}
 114