drivers/watchdog/ast_wdt.c

   1 /*
   2  * Copyright 2017 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 <wdt.h>
  11 #include <asm/io.h>
  12 #include <asm/arch/wdt.h>
  13
  14 #define WDT_AST2500     2500
  15 #define WDT_AST2400     2400
  16
  17 DECLARE_GLOBAL_DATA_PTR;
  18
  19 struct ast_wdt_priv {
  20         struct ast_wdt *regs;
  21 };
  22
  23 static int ast_wdt_start(struct udevice *dev, u64 timeout, ulong flags)
  24 {
  25         struct ast_wdt_priv *priv = dev_get_priv(dev);
  26         ulong driver_data = dev_get_driver_data(dev);
  27         u32 reset_mode = ast_reset_mode_from_flags(flags);
  28
  29         clrsetbits_le32(&priv->regs->ctrl,
  30                         WDT_CTRL_RESET_MASK << WDT_CTRL_RESET_MODE_SHIFT,
  31                         reset_mode << WDT_CTRL_RESET_MODE_SHIFT);
  32
  33         if (driver_data >= WDT_AST2500 && reset_mode == WDT_CTRL_RESET_SOC)
  34                 writel(ast_reset_mask_from_flags(flags),
  35                        &priv->regs->reset_mask);
  36
  37         writel((u32) timeout, &priv->regs->counter_reload_val);
  38         writel(WDT_COUNTER_RESTART_VAL, &priv->regs->counter_restart);
  39         /*
  40          * Setting CLK1MHZ bit is just for compatibility with ast2400 part.
  41          * On ast2500 watchdog timer clock is fixed at 1MHz and the bit is
  42          * read-only
  43          */
  44         setbits_le32(&priv->regs->ctrl,
  45                      WDT_CTRL_EN | WDT_CTRL_RESET | WDT_CTRL_CLK1MHZ);
  46
  47         return 0;
  48 }
  49
  50 static int ast_wdt_stop(struct udevice *dev)
  51 {
  52         struct ast_wdt_priv *priv = dev_get_priv(dev);
  53
  54         clrbits_le32(&priv->regs->ctrl, WDT_CTRL_EN);
  55
  56         return 0;
  57 }
  58
  59 static int ast_wdt_reset(struct udevice *dev)
  60 {
  61         struct ast_wdt_priv *priv = dev_get_priv(dev);
  62
  63         writel(WDT_COUNTER_RESTART_VAL, &priv->regs->counter_restart);
  64
  65         return 0;
  66 }
  67
  68 static int ast_wdt_expire_now(struct udevice *dev, ulong flags)
  69 {
  70         struct ast_wdt_priv *priv = dev_get_priv(dev);
  71         int ret;
  72
  73         ret = ast_wdt_start(dev, 1, flags);
  74         if (ret)
  75                 return ret;
  76
  77         while (readl(&priv->regs->ctrl) & WDT_CTRL_EN)
  78                 ;
  79
  80         return ast_wdt_stop(dev);
  81 }
  82
  83 static int ast_wdt_ofdata_to_platdata(struct udevice *dev)
  84 {
  85         struct ast_wdt_priv *priv = dev_get_priv(dev);
  86
  87         priv->regs = devfdt_get_addr_ptr(dev);
  88         if (IS_ERR(priv->regs))
  89                 return PTR_ERR(priv->regs);
  90
  91         return 0;
  92 }
  93
  94 static const struct wdt_ops ast_wdt_ops = {
  95         .start = ast_wdt_start,
  96         .reset = ast_wdt_reset,
  97         .stop = ast_wdt_stop,
  98         .expire_now = ast_wdt_expire_now,
  99 };
 100
 101 static const struct udevice_id ast_wdt_ids[] = {
 102         { .compatible = "aspeed,wdt", .data = WDT_AST2500 },
 103         { .compatible = "aspeed,ast2500-wdt", .data = WDT_AST2500 },
 104         { .compatible = "aspeed,ast2400-wdt", .data = WDT_AST2400 },
 105         {}
 106 };
 107
 108 static int ast_wdt_probe(struct udevice *dev)
 109 {
 110         debug("%s() wdt%u\n", __func__, dev->seq);
 111         ast_wdt_stop(dev);
 112
 113         return 0;
 114 }
 115
 116 U_BOOT_DRIVER(ast_wdt) = {
 117         .name = "ast_wdt",
 118         .id = UCLASS_WDT,
 119         .of_match = ast_wdt_ids,
 120         .probe = ast_wdt_probe,
 121         .priv_auto_alloc_size = sizeof(struct ast_wdt_priv),
 122         .ofdata_to_platdata = ast_wdt_ofdata_to_platdata,
 123         .ops = &ast_wdt_ops,
 124         .flags = DM_FLAG_PRE_RELOC,
 125 };