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 <clk.h>
  10 #include <timer.h>
  11 #include <linux/err.h>
  12
  13 #include <asm/io.h>
  14 #include <asm/arch-armv7/globaltimer.h>
  15
  16 struct sti_timer_priv {
  17         struct globaltimer *global_timer;
  18 };
  19
  20 static int sti_timer_get_count(struct udevice *dev, u64 *count)
  21 {
  22         struct sti_timer_priv *priv = dev_get_priv(dev);
  23         struct globaltimer *global_timer = priv->global_timer;
  24         u32 low, high;
  25         u64 timer;
  26         u32 old = readl(&global_timer->cnt_h);
  27
  28         while (1) {
  29                 low = readl(&global_timer->cnt_l);
  30                 high = readl(&global_timer->cnt_h);
  31                 if (old == high)
  32                         break;
  33                 else
  34                         old = high;
  35         }
  36         timer = high;
  37         *count = (u64)((timer << 32) | low);
  38
  39         return 0;
  40 }
  41
  42 static int sti_timer_probe(struct udevice *dev)
  43 {
  44         struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
  45         struct sti_timer_priv *priv = dev_get_priv(dev);
  46         struct clk clk;
  47         int err;
  48         ulong ret;
  49
  50         /* get arm global timer base address */
  51         priv->global_timer = (struct globaltimer *)dev_read_addr_ptr(dev);
  52         if (!priv->global_timer)
  53                 return -ENOENT;
  54
  55         err = clk_get_by_index(dev, 0, &clk);
  56         if (!err) {
  57                 ret = clk_get_rate(&clk);
  58                 if (IS_ERR_VALUE(ret))
  59                         return ret;
  60                 uc_priv->clock_rate = ret;
  61         } else {
  62                 uc_priv->clock_rate = CONFIG_SYS_HZ_CLOCK;
  63         }
  64
  65         /* init timer */
  66         writel(0x01, &priv->global_timer->ctl);
  67
  68         return 0;
  69 }
  70
  71 static const struct timer_ops sti_timer_ops = {
  72         .get_count = sti_timer_get_count,
  73 };
  74
  75 static const struct udevice_id sti_timer_ids[] = {
  76         { .compatible = "arm,cortex-a9-global-timer" },
  77         {}
  78 };
  79
  80 U_BOOT_DRIVER(sti_timer) = {
  81         .name = "sti_timer",
  82         .id = UCLASS_TIMER,
  83         .of_match = sti_timer_ids,
  84         .priv_auto_alloc_size = sizeof(struct sti_timer_priv),
  85         .probe = sti_timer_probe,
  86         .ops = &sti_timer_ops,
  87 };