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.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 __iomem *csr;
  26         u32 mask;
  27 };
  28
  29 static int xgene_restart_handler(struct sys_off_data *data)
  30 {
  31         struct xgene_reboot_context *ctx = data->cb_data;
  32
  33         /* Issue the reboot */
  34         writel(ctx->mask, ctx->csr);
  35
  36         mdelay(1000);
  37
  38         dev_emerg(ctx->dev, "Unable to restart system\n");
  39
  40         return NOTIFY_DONE;
  41 }
  42
  43 static int xgene_reboot_probe(struct platform_device *pdev)
  44 {
  45         struct xgene_reboot_context *ctx;
  46         struct device *dev = &pdev->dev;
  47         int err;
  48
  49         ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
  50         if (!ctx)
  51                 return -ENOMEM;
  52
  53         ctx->csr = devm_platform_ioremap_resource(pdev, 0);
  54         if (IS_ERR(ctx->csr)) {
  55                 dev_err(dev, "can not map resource\n");
  56                 return PTR_ERR(ctx->csr);
  57         }
  58
  59         if (of_property_read_u32(dev->of_node, "mask", &ctx->mask))
  60                 ctx->mask = 0xFFFFFFFF;
  61
  62         ctx->dev = dev;
  63         err = devm_register_sys_off_handler(dev, SYS_OFF_MODE_RESTART, 128,
  64                                             xgene_restart_handler, ctx);
  65         if (err)
  66                 dev_err(dev, "cannot register restart handler (err=%d)\n", err);
  67
  68         return err;
  69 }
  70
  71 static const struct of_device_id xgene_reboot_of_match[] = {
  72         { .compatible = "apm,xgene-reboot" },
  73         {}
  74 };
  75
  76 static struct platform_driver xgene_reboot_driver = {
  77         .probe = xgene_reboot_probe,
  78         .driver = {
  79                 .name = "xgene-reboot",
  80                 .of_match_table = xgene_reboot_of_match,
  81         },
  82 };
  83 builtin_platform_driver(xgene_reboot_driver);