drivers/timer/sti-timer.c

   1 /*
   2  * Copyright (C) 2017, STMicroelectronics - All Rights Reserved
   3  * Author(s): Patrice Chotard, <patrice.chotard@st.com> for STMicroelectronics.
   4  *
   5  * SPDX-License-Identifier:     GPL-2.0+
   6  */
   7
   8 #include <common.h>
   9 #include <dm.h>
  10 #include <fdtdec.h>
  11 #include <timer.h>
  12
  13 #include <asm/io.h>
  14 #include <asm/arch-armv7/globaltimer.h>
  15
  16 DECLARE_GLOBAL_DATA_PTR;
  17
  18 struct sti_timer_priv {
  19         struct globaltimer *global_timer;
  20 };
  21
  22 static int sti_timer_get_count(struct udevice *dev, u64 *count)
  23 {
  24         struct sti_timer_priv *priv = dev_get_priv(dev);
  25         struct globaltimer *global_timer = priv->global_timer;
  26         u32 low, high;
  27         u64 timer;
  28         u32 old = readl(&global_timer->cnt_h);
  29
  30         while (1) {
  31                 low = readl(&global_timer->cnt_l);
  32                 high = readl(&global_timer->cnt_h);
  33                 if (old == high)
  34                         break;
  35                 else
  36                         old = high;
  37         }
  38         timer = high;
  39         *count = (u64)((timer << 32) | low);
  40
  41         return 0;
  42 }
  43
  44 static int sti_timer_probe(struct udevice *dev)
  45 {
  46         struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
  47         struct sti_timer_priv *priv = dev_get_priv(dev);
  48         fdt_addr_t addr;
  49
  50         uc_priv->clock_rate = CONFIG_SYS_HZ_CLOCK;
  51
  52         /* get arm global timer base address */
  53         addr = fdtdec_get_addr(gd->fdt_blob, dev_of_offset(dev), "reg");
  54         priv->global_timer = (struct globaltimer *)addr;
  55
  56         /* init timer */
  57         writel(0x01, &priv->global_timer->ctl);
  58
  59         return 0;
  60 }
  61
  62 static const struct timer_ops sti_timer_ops = {
  63         .get_count = sti_timer_get_count,
  64 };
  65
  66 static const struct udevice_id sti_timer_ids[] = {
  67         { .compatible = "arm,cortex-a9-global-timer" },
  68         {}
  69 };
  70
  71 U_BOOT_DRIVER(sti_timer) = {
  72         .name = "sti_timer",
  73         .id = UCLASS_TIMER,
  74         .of_match = sti_timer_ids,
  75         .priv_auto_alloc_size = sizeof(struct sti_timer_priv),
  76         .probe = sti_timer_probe,
  77         .ops = &sti_timer_ops,
  78         .flags = DM_FLAG_PRE_RELOC,
  79 };