1 // SPDX-License-Identifier: (GPL-2.0 OR MIT) 2 /* 3 * Microsemi MIPS SoC reset driver 4 * 5 * License: Dual MIT/GPL 6 * Copyright (c) 2017 Microsemi Corporation 7 */ 8 #include <linux/delay.h> 9 #include <linux/io.h> 10 #include <linux/notifier.h> 11 #include <linux/mfd/syscon.h> 12 #include <linux/of_address.h> 13 #include <linux/of_device.h> 14 #include <linux/platform_device.h> 15 #include <linux/reboot.h> 16 #include <linux/regmap.h> 17 18 struct ocelot_reset_context { 19 void __iomem *base; 20 struct regmap *cpu_ctrl; 21 struct notifier_block restart_handler; 22 }; 23 24 #define ICPU_CFG_CPU_SYSTEM_CTRL_RESET 0x20 25 #define CORE_RST_PROTECT BIT(2) 26 27 #define SOFT_CHIP_RST BIT(0) 28 29 static int ocelot_restart_handle(struct notifier_block *this, 30 unsigned long mode, void *cmd) 31 { 32 struct ocelot_reset_context *ctx = container_of(this, struct 33 ocelot_reset_context, 34 restart_handler); 35 36 /* Make sure the core is not protected from reset */ 37 regmap_update_bits(ctx->cpu_ctrl, ICPU_CFG_CPU_SYSTEM_CTRL_RESET, 38 CORE_RST_PROTECT, 0); 39 40 writel(SOFT_CHIP_RST, ctx->base); 41 42 pr_emerg("Unable to restart system\n"); 43 return NOTIFY_DONE; 44 } 45 46 static int ocelot_reset_probe(struct platform_device *pdev) 47 { 48 struct ocelot_reset_context *ctx; 49 struct resource *res; 50 51 struct device *dev = &pdev->dev; 52 int err; 53 54 ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL); 55 if (!ctx) 56 return -ENOMEM; 57 58 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 59 ctx->base = devm_ioremap_resource(dev, res); 60 if (IS_ERR(ctx->base)) 61 return PTR_ERR(ctx->base); 62 63 ctx->cpu_ctrl = syscon_regmap_lookup_by_compatible("mscc,ocelot-cpu-syscon"); 64 if (IS_ERR(ctx->cpu_ctrl)) 65 return PTR_ERR(ctx->cpu_ctrl); 66 67 ctx->restart_handler.notifier_call = ocelot_restart_handle; 68 ctx->restart_handler.priority = 192; 69 err = register_restart_handler(&ctx->restart_handler); 70 if (err) 71 dev_err(dev, "can't register restart notifier (err=%d)\n", err); 72 73 return err; 74 } 75 76 static const struct of_device_id ocelot_reset_of_match[] = { 77 { .compatible = "mscc,ocelot-chip-reset" }, 78 {} 79 }; 80 81 static struct platform_driver ocelot_reset_driver = { 82 .probe = ocelot_reset_probe, 83 .driver = { 84 .name = "ocelot-chip-reset", 85 .of_match_table = ocelot_reset_of_match, 86 }, 87 }; 88 builtin_platform_driver(ocelot_reset_driver); 89