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); 110