drivers/timer/ast_timer.c

   1 /*
   2  * Copyright 2016 Google Inc.
   3  *
   4  * SPDX-License-Identifier:     GPL-2.0+
   5  */
   6
   7 #include <common.h>
   8 #include <dm.h>
   9 #include <errno.h>
  10 #include <timer.h>
  11 #include <asm/io.h>
  12 #include <asm/arch/timer.h>
  13
  14 DECLARE_GLOBAL_DATA_PTR;
  15
  16 #define AST_TICK_TIMER  1
  17 #define AST_TMC_RELOAD_VAL  0xffffffff
  18
  19 struct ast_timer_priv {
  20         struct ast_timer *regs;
  21         struct ast_timer_counter *tmc;
  22 };
  23
  24 static struct ast_timer_counter *ast_get_timer_counter(struct ast_timer *timer,
  25                                                        int n)
  26 {
  27         if (n > 3)
  28                 return &timer->timers2[n - 4];
  29         else
  30                 return &timer->timers1[n - 1];
  31 }
  32
  33 static int ast_timer_probe(struct udevice *dev)
  34 {
  35         struct ast_timer_priv *priv = dev_get_priv(dev);
  36         struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
  37
  38         writel(AST_TMC_RELOAD_VAL, &priv->tmc->reload_val);
  39
  40         /*
  41          * Stop the timer. This will also load reload_val into
  42          * the status register.
  43          */
  44         clrbits_le32(&priv->regs->ctrl1,
  45                      AST_TMC_EN << AST_TMC_CTRL1_SHIFT(AST_TICK_TIMER));
  46         /* Start the timer from the fixed 1MHz clock. */
  47         setbits_le32(&priv->regs->ctrl1,
  48                      (AST_TMC_EN | AST_TMC_1MHZ) <<
  49                      AST_TMC_CTRL1_SHIFT(AST_TICK_TIMER));
  50
  51         uc_priv->clock_rate = AST_TMC_RATE;
  52
  53         return 0;
  54 }
  55
  56 static int ast_timer_get_count(struct udevice *dev, u64 *count)
  57 {
  58         struct ast_timer_priv *priv = dev_get_priv(dev);
  59
  60         *count = AST_TMC_RELOAD_VAL - readl(&priv->tmc->status);
  61
  62         return 0;
  63 }
  64
  65 static int ast_timer_ofdata_to_platdata(struct udevice *dev)
  66 {
  67         struct ast_timer_priv *priv = dev_get_priv(dev);
  68
  69         priv->regs = dev_get_addr_ptr(dev);
  70         if (IS_ERR(priv->regs))
  71                 return PTR_ERR(priv->regs);
  72
  73         priv->tmc = ast_get_timer_counter(priv->regs, AST_TICK_TIMER);
  74
  75         return 0;
  76 }
  77
  78 static const struct timer_ops ast_timer_ops = {
  79         .get_count = ast_timer_get_count,
  80 };
  81
  82 static const struct udevice_id ast_timer_ids[] = {
  83         { .compatible = "aspeed,ast2500-timer" },
  84         { .compatible = "aspeed,ast2400-timer" },
  85         { }
  86 };
  87
  88 U_BOOT_DRIVER(ast_timer) = {
  89         .name = "ast_timer",
  90         .id = UCLASS_TIMER,
  91         .of_match = ast_timer_ids,
  92         .probe = ast_timer_probe,
  93         .priv_auto_alloc_size = sizeof(struct ast_timer_priv),
  94         .ofdata_to_platdata = ast_timer_ofdata_to_platdata,
  95         .ops = &ast_timer_ops,
  96         .flags = DM_FLAG_PRE_RELOC,
  97 };