drivers/power/reset/xgene-reboot.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * AppliedMicro X-Gene SoC Reboot Driver
   4  *
   5  * Copyright (c) 2013, Applied Micro Circuits Corporation
   6  * Author: Feng Kan <fkan@apm.com>
   7  * Author: Loc Ho <lho@apm.com>
   8  *
   9  * This driver provides system reboot functionality for APM X-Gene SoC.
  10  * For system shutdown, this is board specify. If a board designer
  11  * implements GPIO shutdown, use the gpio-poweroff.c driver.
  12  */
  13 #include <linux/delay.h>
  14 #include <linux/io.h>
  15 #include <linux/notifier.h>
  16 #include <linux/of_device.h>
  17 #include <linux/of_address.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/reboot.h>
  20 #include <linux/stat.h>
  21 #include <linux/slab.h>
  22
  23 struct xgene_reboot_context {
  24         struct device *dev;
  25         void *csr;
  26         u32 mask;
  27         struct notifier_block restart_handler;
  28 };
  29
  30 static int xgene_restart_handler(struct notifier_block *this,
  31                                  unsigned long mode, void *cmd)
  32 {
  33         struct xgene_reboot_context *ctx =
  34                 container_of(this, struct xgene_reboot_context,
  35                              restart_handler);
  36
  37         /* Issue the reboot */
  38         writel(ctx->mask, ctx->csr);
  39
  40         mdelay(1000);
  41
  42         dev_emerg(ctx->dev, "Unable to restart system\n");
  43
  44         return NOTIFY_DONE;
  45 }
  46
  47 static int xgene_reboot_probe(struct platform_device *pdev)
  48 {
  49         struct xgene_reboot_context *ctx;
  50         struct device *dev = &pdev->dev;
  51         int err;
  52
  53         ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
  54         if (!ctx)
  55                 return -ENOMEM;
  56
  57         ctx->csr = of_iomap(dev->of_node, 0);
  58         if (!ctx->csr) {
  59                 dev_err(dev, "can not map resource\n");
  60                 return -ENODEV;
  61         }
  62
  63         if (of_property_read_u32(dev->of_node, "mask", &ctx->mask))
  64                 ctx->mask = 0xFFFFFFFF;
  65
  66         ctx->dev = dev;
  67         ctx->restart_handler.notifier_call = xgene_restart_handler;
  68         ctx->restart_handler.priority = 128;
  69         err = register_restart_handler(&ctx->restart_handler);
  70         if (err) {
  71                 iounmap(ctx->csr);
  72                 dev_err(dev, "cannot register restart handler (err=%d)\n", err);
  73         }
  74
  75         return err;
  76 }
  77
  78 static const struct of_device_id xgene_reboot_of_match[] = {
  79         { .compatible = "apm,xgene-reboot" },
  80         {}
  81 };
  82
  83 static struct platform_driver xgene_reboot_driver = {
  84         .probe = xgene_reboot_probe,
  85         .driver = {
  86                 .name = "xgene-reboot",
  87                 .of_match_table = xgene_reboot_of_match,
  88         },
  89 };
  90
  91 static int __init xgene_reboot_init(void)
  92 {
  93         return platform_driver_register(&xgene_reboot_driver);
  94 }
  95 device_initcall(xgene_reboot_init);