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); 96