drivers/power/reset/xgene-reboot.c

   1 /*
   2  * AppliedMicro X-Gene SoC Reboot Driver
   3  *
   4  * Copyright (c) 2013, Applied Micro Circuits Corporation
   5  * Author: Feng Kan <fkan@apm.com>
   6  * Author: Loc Ho <lho@apm.com>
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License as
  10  * published by the Free Software Foundation; either version 2 of
  11  * the License, or (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  21  * MA 02111-1307 USA
  22  *
  23  * This driver provides system reboot functionality for APM X-Gene SoC.
  24  * For system shutdown, this is board specify. If a board designer
  25  * implements GPIO shutdown, use the gpio-poweroff.c driver.
  26  */
  27 #include <linux/delay.h>
  28 #include <linux/io.h>
  29 #include <linux/notifier.h>
  30 #include <linux/of_device.h>
  31 #include <linux/of_address.h>
  32 #include <linux/platform_device.h>
  33 #include <linux/reboot.h>
  34 #include <linux/stat.h>
  35 #include <linux/slab.h>
  36
  37 struct xgene_reboot_context {
  38         struct device *dev;
  39         void *csr;
  40         u32 mask;
  41         struct notifier_block restart_handler;
  42 };
  43
  44 static int xgene_restart_handler(struct notifier_block *this,
  45                                  unsigned long mode, void *cmd)
  46 {
  47         struct xgene_reboot_context *ctx =
  48                 container_of(this, struct xgene_reboot_context,
  49                              restart_handler);
  50
  51         /* Issue the reboot */
  52         writel(ctx->mask, ctx->csr);
  53
  54         mdelay(1000);
  55
  56         dev_emerg(ctx->dev, "Unable to restart system\n");
  57
  58         return NOTIFY_DONE;
  59 }
  60
  61 static int xgene_reboot_probe(struct platform_device *pdev)
  62 {
  63         struct xgene_reboot_context *ctx;
  64         struct device *dev = &pdev->dev;
  65         int err;
  66
  67         ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
  68         if (!ctx)
  69                 return -ENOMEM;
  70
  71         ctx->csr = of_iomap(dev->of_node, 0);
  72         if (!ctx->csr) {
  73                 dev_err(dev, "can not map resource\n");
  74                 return -ENODEV;
  75         }
  76
  77         if (of_property_read_u32(dev->of_node, "mask", &ctx->mask))
  78                 ctx->mask = 0xFFFFFFFF;
  79
  80         ctx->dev = dev;
  81         ctx->restart_handler.notifier_call = xgene_restart_handler;
  82         ctx->restart_handler.priority = 128;
  83         err = register_restart_handler(&ctx->restart_handler);
  84         if (err) {
  85                 iounmap(ctx->csr);
  86                 dev_err(dev, "cannot register restart handler (err=%d)\n", err);
  87         }
  88
  89         return err;
  90 }
  91
  92 static const struct of_device_id xgene_reboot_of_match[] = {
  93         { .compatible = "apm,xgene-reboot" },
  94         {}
  95 };
  96
  97 static struct platform_driver xgene_reboot_driver = {
  98         .probe = xgene_reboot_probe,
  99         .driver = {
 100                 .name = "xgene-reboot",
 101                 .of_match_table = xgene_reboot_of_match,
 102         },
 103 };
 104
 105 static int __init xgene_reboot_init(void)
 106 {
 107         return platform_driver_register(&xgene_reboot_driver);
 108 }
 109 device_initcall(xgene_reboot_init);