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