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 <asm/io.h>
  35#include <asm/arch/hardware.h>
  36#include <asm/arch/clk.h>
  37
  38DECLARE_GLOBAL_DATA_PTR;
  39
  40struct scu_timer {
  41        u32 load; /* Timer Load Register */
  42        u32 counter; /* Timer Counter Register */
  43        u32 control; /* Timer Control Register */
  44};
  45
  46static struct scu_timer *timer_base =
  47                              (struct scu_timer *)ZYNQ_SCUTIMER_BASEADDR;
  48
  49#define SCUTIMER_CONTROL_PRESCALER_MASK 0x0000FF00 /* Prescaler */
  50#define SCUTIMER_CONTROL_PRESCALER_SHIFT        8
  51#define SCUTIMER_CONTROL_AUTO_RELOAD_MASK       0x00000002 /* Auto-reload */
  52#define SCUTIMER_CONTROL_ENABLE_MASK            0x00000001 /* Timer enable */
  53
  54#define TIMER_LOAD_VAL 0xFFFFFFFF
  55#define TIMER_PRESCALE 255
  56
  57int timer_init(void)
  58{
  59        const u32 emask = SCUTIMER_CONTROL_AUTO_RELOAD_MASK |
  60                        (TIMER_PRESCALE << SCUTIMER_CONTROL_PRESCALER_SHIFT) |
  61                        SCUTIMER_CONTROL_ENABLE_MASK;
  62
  63        struct udevice *dev;
  64        struct clk clk;
  65        int ret;
  66
  67        ret = uclass_get_device_by_driver(UCLASS_CLK,
  68                DM_GET_DRIVER(zynq_clk), &dev);
  69        if (ret)
  70                return ret;
  71
  72        clk.id = cpu_6or4x_clk;
  73        ret = clk_request(dev, &clk);
  74        if (ret < 0)
  75                return ret;
  76
  77        gd->cpu_clk = clk_get_rate(&clk);
  78
  79        clk_free(&clk);
  80
  81        gd->arch.timer_rate_hz = (gd->cpu_clk / 2) / (TIMER_PRESCALE + 1);
  82
  83        /* Load the timer counter register */
  84        writel(0xFFFFFFFF, &timer_base->load);
  85
  86        /*
  87         * Start the A9Timer device
  88         * Enable Auto reload mode, Clear prescaler control bits
  89         * Set prescaler value, Enable the decrementer
  90         */
  91        clrsetbits_le32(&timer_base->control, SCUTIMER_CONTROL_PRESCALER_MASK,
  92                                                                emask);
  93
  94        /* Reset time */
  95        gd->arch.lastinc = readl(&timer_base->counter) /
  96                                (gd->arch.timer_rate_hz / CONFIG_SYS_HZ);
  97        gd->arch.tbl = 0;
  98
  99        return 0;
 100}
 101
 102/*
 103 * This function is derived from PowerPC code (timebase clock frequency).
 104 * On ARM it returns the number of timer ticks per second.
 105 */
 106ulong get_tbclk(void)
 107{
 108        return gd->arch.timer_rate_hz;
 109}
 110