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/io.h>
  28 #include <linux/of_device.h>
  29 #include <linux/of_address.h>
  30 #include <linux/platform_device.h>
  31 #include <linux/stat.h>
  32 #include <linux/slab.h>
  33 #include <asm/system_misc.h>
  34
  35 struct xgene_reboot_context {
  36         struct platform_device *pdev;
  37         void *csr;
  38         u32 mask;
  39 };
  40
  41 static struct xgene_reboot_context *xgene_restart_ctx;
  42
  43 static void xgene_restart(char str, const char *cmd)
  44 {
  45         struct xgene_reboot_context *ctx = xgene_restart_ctx;
  46         unsigned long timeout;
  47
  48         /* Issue the reboot */
  49         if (ctx)
  50                 writel(ctx->mask, ctx->csr);
  51
  52         timeout = jiffies + HZ;
  53         while (time_before(jiffies, timeout))
  54                 cpu_relax();
  55
  56         dev_emerg(&ctx->pdev->dev, "Unable to restart system\n");
  57 }
  58
  59 static int xgene_reboot_probe(struct platform_device *pdev)
  60 {
  61         struct xgene_reboot_context *ctx;
  62
  63         ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
  64         if (!ctx) {
  65                 dev_err(&pdev->dev, "out of memory for context\n");
  66                 return -ENODEV;
  67         }
  68
  69         ctx->csr = of_iomap(pdev->dev.of_node, 0);
  70         if (!ctx->csr) {
  71                 devm_kfree(&pdev->dev, ctx);
  72                 dev_err(&pdev->dev, "can not map resource\n");
  73                 return -ENODEV;
  74         }
  75
  76         if (of_property_read_u32(pdev->dev.of_node, "mask", &ctx->mask))
  77                 ctx->mask = 0xFFFFFFFF;
  78
  79         ctx->pdev = pdev;
  80         arm_pm_restart = xgene_restart;
  81         xgene_restart_ctx = ctx;
  82
  83         return 0;
  84 }
  85
  86 static struct of_device_id xgene_reboot_of_match[] = {
  87         { .compatible = "apm,xgene-reboot" },
  88         {}
  89 };
  90
  91 static struct platform_driver xgene_reboot_driver = {
  92         .probe = xgene_reboot_probe,
  93         .driver = {
  94                 .name = "xgene-reboot",
  95                 .of_match_table = xgene_reboot_of_match,
  96         },
  97 };
  98
  99 static int __init xgene_reboot_init(void)
 100 {
 101         return platform_driver_register(&xgene_reboot_driver);
 102 }
 103 device_initcall(xgene_reboot_init);