1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2018, Intel Corporation 4 * Copied from reset-sunxi.c 5 */ 6 7 #include <linux/err.h> 8 #include <linux/io.h> 9 #include <linux/init.h> 10 #include <linux/of.h> 11 #include <linux/of_address.h> 12 #include <linux/platform_device.h> 13 #include <linux/reset-controller.h> 14 #include <linux/reset/reset-simple.h> 15 #include <linux/reset/socfpga.h> 16 #include <linux/slab.h> 17 #include <linux/spinlock.h> 18 #include <linux/types.h> 19 20 #define SOCFPGA_NR_BANKS 8 21 22 static int a10_reset_init(struct device_node *np) 23 { 24 struct reset_simple_data *data; 25 struct resource res; 26 resource_size_t size; 27 int ret; 28 u32 reg_offset = 0x10; 29 30 data = kzalloc(sizeof(*data), GFP_KERNEL); 31 if (!data) 32 return -ENOMEM; 33 34 ret = of_address_to_resource(np, 0, &res); 35 if (ret) 36 goto err_alloc; 37 38 size = resource_size(&res); 39 if (!request_mem_region(res.start, size, np->name)) { 40 ret = -EBUSY; 41 goto err_alloc; 42 } 43 44 data->membase = ioremap(res.start, size); 45 if (!data->membase) { 46 ret = -ENOMEM; 47 goto release_region; 48 } 49 50 if (of_property_read_u32(np, "altr,modrst-offset", ®_offset)) 51 pr_warn("missing altr,modrst-offset property, assuming 0x10\n"); 52 data->membase += reg_offset; 53 54 spin_lock_init(&data->lock); 55 56 data->rcdev.owner = THIS_MODULE; 57 data->rcdev.nr_resets = SOCFPGA_NR_BANKS * 32; 58 data->rcdev.ops = &reset_simple_ops; 59 data->rcdev.of_node = np; 60 data->status_active_low = true; 61 62 ret = reset_controller_register(&data->rcdev); 63 if (ret) 64 pr_err("unable to register device\n"); 65 66 return ret; 67 68 release_region: 69 release_mem_region(res.start, size); 70 71 err_alloc: 72 kfree(data); 73 return ret; 74 }; 75 76 /* 77 * These are the reset controller we need to initialize early on in 78 * our system, before we can even think of using a regular device 79 * driver for it. 80 * The controllers that we can register through the regular device 81 * model are handled by the simple reset driver directly. 82 */ 83 static const struct of_device_id socfpga_early_reset_dt_ids[] __initconst = { 84 { .compatible = "altr,rst-mgr", }, 85 { /* sentinel */ }, 86 }; 87 88 void __init socfpga_reset_init(void) 89 { 90 struct device_node *np; 91 92 for_each_matching_node(np, socfpga_early_reset_dt_ids) 93 a10_reset_init(np); 94 } 95 96 /* 97 * The early driver is problematic, because it doesn't register 98 * itself as a driver. This causes certain device links to prevent 99 * consumer devices from probing. The hacky solution is to register 100 * an empty driver, whose only job is to attach itself to the reset 101 * manager and call probe. 102 */ 103 static const struct of_device_id socfpga_reset_dt_ids[] = { 104 { .compatible = "altr,rst-mgr", }, 105 { /* sentinel */ }, 106 }; 107 108 static int reset_simple_probe(struct platform_device *pdev) 109 { 110 return 0; 111 } 112 113 static struct platform_driver reset_socfpga_driver = { 114 .probe = reset_simple_probe, 115 .driver = { 116 .name = "socfpga-reset", 117 .of_match_table = socfpga_reset_dt_ids, 118 }, 119 }; 120 builtin_platform_driver(reset_socfpga_driver); 121