drivers/watchdog/ast_wdt.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright 2017 Google, Inc
   4  */
   5
   6 #include <common.h>
   7 #include <dm.h>
   8 #include <errno.h>
   9 #include <wdt.h>
  10 #include <asm/io.h>
  11 #include <asm/arch/wdt.h>
  12
  13 #define WDT_AST2500     2500
  14 #define WDT_AST2400     2400
  15
  16 struct ast_wdt_priv {
  17         struct ast_wdt *regs;
  18 };
  19
  20 static int ast_wdt_start(struct udevice *dev, u64 timeout, ulong flags)
  21 {
  22         struct ast_wdt_priv *priv = dev_get_priv(dev);
  23         ulong driver_data = dev_get_driver_data(dev);
  24         u32 reset_mode = ast_reset_mode_from_flags(flags);
  25
  26         clrsetbits_le32(&priv->regs->ctrl,
  27                         WDT_CTRL_RESET_MASK << WDT_CTRL_RESET_MODE_SHIFT,
  28                         reset_mode << WDT_CTRL_RESET_MODE_SHIFT);
  29
  30         if (driver_data >= WDT_AST2500 && reset_mode == WDT_CTRL_RESET_SOC)
  31                 writel(ast_reset_mask_from_flags(flags),
  32                        &priv->regs->reset_mask);
  33
  34         writel((u32) timeout, &priv->regs->counter_reload_val);
  35         writel(WDT_COUNTER_RESTART_VAL, &priv->regs->counter_restart);
  36         /*
  37          * Setting CLK1MHZ bit is just for compatibility with ast2400 part.
  38          * On ast2500 watchdog timer clock is fixed at 1MHz and the bit is
  39          * read-only
  40          */
  41         setbits_le32(&priv->regs->ctrl,
  42                      WDT_CTRL_EN | WDT_CTRL_RESET | WDT_CTRL_CLK1MHZ);
  43
  44         return 0;
  45 }
  46
  47 static int ast_wdt_stop(struct udevice *dev)
  48 {
  49         struct ast_wdt_priv *priv = dev_get_priv(dev);
  50
  51         clrbits_le32(&priv->regs->ctrl, WDT_CTRL_EN);
  52
  53         return 0;
  54 }
  55
  56 static int ast_wdt_reset(struct udevice *dev)
  57 {
  58         struct ast_wdt_priv *priv = dev_get_priv(dev);
  59
  60         writel(WDT_COUNTER_RESTART_VAL, &priv->regs->counter_restart);
  61
  62         return 0;
  63 }
  64
  65 static int ast_wdt_expire_now(struct udevice *dev, ulong flags)
  66 {
  67         struct ast_wdt_priv *priv = dev_get_priv(dev);
  68         int ret;
  69
  70         ret = ast_wdt_start(dev, 1, flags);
  71         if (ret)
  72                 return ret;
  73
  74         while (readl(&priv->regs->ctrl) & WDT_CTRL_EN)
  75                 ;
  76
  77         return ast_wdt_stop(dev);
  78 }
  79
  80 static int ast_wdt_ofdata_to_platdata(struct udevice *dev)
  81 {
  82         struct ast_wdt_priv *priv = dev_get_priv(dev);
  83
  84         priv->regs = devfdt_get_addr_ptr(dev);
  85         if (IS_ERR(priv->regs))
  86                 return PTR_ERR(priv->regs);
  87
  88         return 0;
  89 }
  90
  91 static const struct wdt_ops ast_wdt_ops = {
  92         .start = ast_wdt_start,
  93         .reset = ast_wdt_reset,
  94         .stop = ast_wdt_stop,
  95         .expire_now = ast_wdt_expire_now,
  96 };
  97
  98 static const struct udevice_id ast_wdt_ids[] = {
  99         { .compatible = "aspeed,wdt", .data = WDT_AST2500 },
 100         { .compatible = "aspeed,ast2500-wdt", .data = WDT_AST2500 },
 101         { .compatible = "aspeed,ast2400-wdt", .data = WDT_AST2400 },
 102         {}
 103 };
 104
 105 static int ast_wdt_probe(struct udevice *dev)
 106 {
 107         debug("%s() wdt%u\n", __func__, dev->seq);
 108         ast_wdt_stop(dev);
 109
 110         return 0;
 111 }
 112
 113 U_BOOT_DRIVER(ast_wdt) = {
 114         .name = "ast_wdt",
 115         .id = UCLASS_WDT,
 116         .of_match = ast_wdt_ids,
 117         .probe = ast_wdt_probe,
 118         .priv_auto_alloc_size = sizeof(struct ast_wdt_priv),
 119         .ofdata_to_platdata = ast_wdt_ofdata_to_platdata,
 120         .ops = &ast_wdt_ops,
 121         .flags = DM_FLAG_PRE_RELOC,
 122 };