drivers/reset/ast2500-reset.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 <misc.h>
  10 #include <reset.h>
  11 #include <reset-uclass.h>
  12 #include <wdt.h>
  13 #include <asm/io.h>
  14 #include <asm/arch/scu_ast2500.h>
  15 #include <asm/arch/wdt.h>
  16
  17 DECLARE_GLOBAL_DATA_PTR;
  18
  19 struct ast2500_reset_priv {
  20         /* WDT used to perform resets. */
  21         struct udevice *wdt;
  22         struct ast2500_scu *scu;
  23 };
  24
  25 static int ast2500_ofdata_to_platdata(struct udevice *dev)
  26 {
  27         struct ast2500_reset_priv *priv = dev_get_priv(dev);
  28         int ret;
  29
  30         ret = uclass_get_device_by_phandle(UCLASS_WDT, dev, "aspeed,wdt",
  31                                            &priv->wdt);
  32         if (ret) {
  33                 debug("%s: can't find WDT for reset controller", __func__);
  34                 return ret;
  35         }
  36
  37         return 0;
  38 }
  39
  40 static int ast2500_reset_assert(struct reset_ctl *reset_ctl)
  41 {
  42         struct ast2500_reset_priv *priv = dev_get_priv(reset_ctl->dev);
  43         u32 reset_mode, reset_mask;
  44         bool reset_sdram;
  45         int ret;
  46
  47         /*
  48          * To reset SDRAM, a specifal flag in SYSRESET register
  49          * needs to be enabled first
  50          */
  51         reset_mode = ast_reset_mode_from_flags(reset_ctl->id);
  52         reset_mask = ast_reset_mask_from_flags(reset_ctl->id);
  53         reset_sdram = reset_mode == WDT_CTRL_RESET_SOC &&
  54                 (reset_mask & WDT_RESET_SDRAM);
  55
  56         if (reset_sdram) {
  57                 ast_scu_unlock(priv->scu);
  58                 setbits_le32(&priv->scu->sysreset_ctrl1,
  59                              SCU_SYSRESET_SDRAM_WDT);
  60                 ret = wdt_expire_now(priv->wdt, reset_ctl->id);
  61                 clrbits_le32(&priv->scu->sysreset_ctrl1,
  62                              SCU_SYSRESET_SDRAM_WDT);
  63                 ast_scu_lock(priv->scu);
  64         } else {
  65                 ret = wdt_expire_now(priv->wdt, reset_ctl->id);
  66         }
  67
  68         return ret;
  69 }
  70
  71 static int ast2500_reset_request(struct reset_ctl *reset_ctl)
  72 {
  73         debug("%s(reset_ctl=%p) (dev=%p, id=%lu)\n", __func__, reset_ctl,
  74               reset_ctl->dev, reset_ctl->id);
  75
  76         return 0;
  77 }
  78
  79 static int ast2500_reset_probe(struct udevice *dev)
  80 {
  81         struct ast2500_reset_priv *priv = dev_get_priv(dev);
  82
  83         priv->scu = ast_get_scu();
  84
  85         return 0;
  86 }
  87
  88 static const struct udevice_id ast2500_reset_ids[] = {
  89         { .compatible = "aspeed,ast2500-reset" },
  90         { }
  91 };
  92
  93 struct reset_ops ast2500_reset_ops = {
  94         .rst_assert = ast2500_reset_assert,
  95         .request = ast2500_reset_request,
  96 };
  97
  98 U_BOOT_DRIVER(ast2500_reset) = {
  99         .name           = "ast2500_reset",
 100         .id             = UCLASS_RESET,
 101         .of_match = ast2500_reset_ids,
 102         .probe = ast2500_reset_probe,
 103         .ops = &ast2500_reset_ops,
 104         .ofdata_to_platdata = ast2500_ofdata_to_platdata,
 105         .priv_auto_alloc_size = sizeof(struct ast2500_reset_priv),
 106 };