drivers/timer/sti-timer.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (C) 2017, STMicroelectronics - All Rights Reserved
   4  * Author(s): Patrice Chotard, <patrice.chotard@st.com> for STMicroelectronics.
   5  */
   6
   7 #include <common.h>
   8 #include <dm.h>
   9 #include <timer.h>
  10
  11 #include <asm/io.h>
  12 #include <asm/arch-armv7/globaltimer.h>
  13
  14 struct sti_timer_priv {
  15         struct globaltimer *global_timer;
  16 };
  17
  18 static int sti_timer_get_count(struct udevice *dev, u64 *count)
  19 {
  20         struct sti_timer_priv *priv = dev_get_priv(dev);
  21         struct globaltimer *global_timer = priv->global_timer;
  22         u32 low, high;
  23         u64 timer;
  24         u32 old = readl(&global_timer->cnt_h);
  25
  26         while (1) {
  27                 low = readl(&global_timer->cnt_l);
  28                 high = readl(&global_timer->cnt_h);
  29                 if (old == high)
  30                         break;
  31                 else
  32                         old = high;
  33         }
  34         timer = high;
  35         *count = (u64)((timer << 32) | low);
  36
  37         return 0;
  38 }
  39
  40 static int sti_timer_probe(struct udevice *dev)
  41 {
  42         struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
  43         struct sti_timer_priv *priv = dev_get_priv(dev);
  44
  45         uc_priv->clock_rate = CONFIG_SYS_HZ_CLOCK;
  46
  47         /* get arm global timer base address */
  48         priv->global_timer = (struct globaltimer *)dev_read_addr_ptr(dev);
  49         if (!priv->global_timer)
  50                 return -ENOENT;
  51
  52         /* init timer */
  53         writel(0x01, &priv->global_timer->ctl);
  54
  55         return 0;
  56 }
  57
  58 static const struct timer_ops sti_timer_ops = {
  59         .get_count = sti_timer_get_count,
  60 };
  61
  62 static const struct udevice_id sti_timer_ids[] = {
  63         { .compatible = "arm,cortex-a9-global-timer" },
  64         {}
  65 };
  66
  67 U_BOOT_DRIVER(sti_timer) = {
  68         .name = "sti_timer",
  69         .id = UCLASS_TIMER,
  70         .of_match = sti_timer_ids,
  71         .priv_auto_alloc_size = sizeof(struct sti_timer_priv),
  72         .probe = sti_timer_probe,
  73         .ops = &sti_timer_ops,
  74 };