drivers/timer/ast_timer.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright 2016 Google Inc.
   4  */
   5
   6 #include <common.h>
   7 #include <dm.h>
   8 #include <errno.h>
   9 #include <timer.h>
  10 #include <asm/io.h>
  11 #include <asm/arch/timer.h>
  12 #include <linux/err.h>
  13
  14 #define AST_TICK_TIMER  1
  15 #define AST_TMC_RELOAD_VAL  0xffffffff
  16
  17 struct ast_timer_priv {
  18         struct ast_timer *regs;
  19         struct ast_timer_counter *tmc;
  20 };
  21
  22 static struct ast_timer_counter *ast_get_timer_counter(struct ast_timer *timer,
  23                                                        int n)
  24 {
  25         if (n > 3)
  26                 return &timer->timers2[n - 4];
  27         else
  28                 return &timer->timers1[n - 1];
  29 }
  30
  31 static int ast_timer_probe(struct udevice *dev)
  32 {
  33         struct ast_timer_priv *priv = dev_get_priv(dev);
  34         struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
  35
  36         writel(AST_TMC_RELOAD_VAL, &priv->tmc->reload_val);
  37
  38         /*
  39          * Stop the timer. This will also load reload_val into
  40          * the status register.
  41          */
  42         clrbits_le32(&priv->regs->ctrl1,
  43                      AST_TMC_EN << AST_TMC_CTRL1_SHIFT(AST_TICK_TIMER));
  44         /* Start the timer from the fixed 1MHz clock. */
  45         setbits_le32(&priv->regs->ctrl1,
  46                      (AST_TMC_EN | AST_TMC_1MHZ) <<
  47                      AST_TMC_CTRL1_SHIFT(AST_TICK_TIMER));
  48
  49         uc_priv->clock_rate = AST_TMC_RATE;
  50
  51         return 0;
  52 }
  53
  54 static int ast_timer_get_count(struct udevice *dev, u64 *count)
  55 {
  56         struct ast_timer_priv *priv = dev_get_priv(dev);
  57
  58         *count = AST_TMC_RELOAD_VAL - readl(&priv->tmc->status);
  59
  60         return 0;
  61 }
  62
  63 static int ast_timer_ofdata_to_platdata(struct udevice *dev)
  64 {
  65         struct ast_timer_priv *priv = dev_get_priv(dev);
  66
  67         priv->regs = dev_read_addr_ptr(dev);
  68         if (!priv->regs)
  69                 return -EINVAL;
  70
  71         priv->tmc = ast_get_timer_counter(priv->regs, AST_TICK_TIMER);
  72
  73         return 0;
  74 }
  75
  76 static const struct timer_ops ast_timer_ops = {
  77         .get_count = ast_timer_get_count,
  78 };
  79
  80 static const struct udevice_id ast_timer_ids[] = {
  81         { .compatible = "aspeed,ast2500-timer" },
  82         { .compatible = "aspeed,ast2400-timer" },
  83         { }
  84 };
  85
  86 U_BOOT_DRIVER(ast_timer) = {
  87         .name = "ast_timer",
  88         .id = UCLASS_TIMER,
  89         .of_match = ast_timer_ids,
  90         .probe = ast_timer_probe,
  91         .priv_auto_alloc_size = sizeof(struct ast_timer_priv),
  92         .ofdata_to_platdata = ast_timer_ofdata_to_platdata,
  93         .ops = &ast_timer_ops,
  94 };