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@foss.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 u64 sti_timer_get_count(struct udevice *dev)
  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         return (u64)((timer << 32) | low);
  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         struct clk clk;
  45         int err;
  46         ulong ret;
  47
  48         /* get arm global timer base address */
  49         priv->global_timer = (struct globaltimer *)dev_read_addr_ptr(dev);
  50         if (!priv->global_timer)
  51                 return -ENOENT;
  52
  53         err = clk_get_by_index(dev, 0, &clk);
  54         if (!err) {
  55                 ret = clk_get_rate(&clk);
  56                 if (IS_ERR_VALUE(ret))
  57                         return ret;
  58                 uc_priv->clock_rate = ret;
  59         } else {
  60                 uc_priv->clock_rate = CONFIG_SYS_HZ_CLOCK;
  61         }
  62
  63         /* init timer */
  64         writel(0x01, &priv->global_timer->ctl);
  65
  66         return 0;
  67 }
  68
  69 static const struct timer_ops sti_timer_ops = {
  70         .get_count = sti_timer_get_count,
  71 };
  72
  73 static const struct udevice_id sti_timer_ids[] = {
  74         { .compatible = "arm,cortex-a9-global-timer" },
  75         {}
  76 };
  77
  78 U_BOOT_DRIVER(sti_timer) = {
  79         .name = "sti_timer",
  80         .id = UCLASS_TIMER,
  81         .of_match = sti_timer_ids,
  82         .priv_auto_alloc_size = sizeof(struct sti_timer_priv),
  83         .probe = sti_timer_probe,
  84         .ops = &sti_timer_ops,
  85 };