1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * System Control and Management Interface (SCMI) Message Protocol bus layer 4 * 5 * Copyright (C) 2018 ARM Ltd. 6 */ 7 8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 9 10 #include <linux/types.h> 11 #include <linux/module.h> 12 #include <linux/kernel.h> 13 #include <linux/slab.h> 14 #include <linux/device.h> 15 16 #include "common.h" 17 18 static DEFINE_IDA(scmi_bus_id); 19 static DEFINE_IDR(scmi_protocols); 20 static DEFINE_SPINLOCK(protocol_lock); 21 22 static const struct scmi_device_id * 23 scmi_dev_match_id(struct scmi_device *scmi_dev, struct scmi_driver *scmi_drv) 24 { 25 const struct scmi_device_id *id = scmi_drv->id_table; 26 27 if (!id) 28 return NULL; 29 30 for (; id->protocol_id; id++) 31 if (id->protocol_id == scmi_dev->protocol_id) { 32 if (!id->name) 33 return id; 34 else if (!strcmp(id->name, scmi_dev->name)) 35 return id; 36 } 37 38 return NULL; 39 } 40 41 static int scmi_dev_match(struct device *dev, struct device_driver *drv) 42 { 43 struct scmi_driver *scmi_drv = to_scmi_driver(drv); 44 struct scmi_device *scmi_dev = to_scmi_dev(dev); 45 const struct scmi_device_id *id; 46 47 id = scmi_dev_match_id(scmi_dev, scmi_drv); 48 if (id) 49 return 1; 50 51 return 0; 52 } 53 54 static int scmi_protocol_init(int protocol_id, struct scmi_handle *handle) 55 { 56 scmi_prot_init_fn_t fn = idr_find(&scmi_protocols, protocol_id); 57 58 if (unlikely(!fn)) 59 return -EINVAL; 60 return fn(handle); 61 } 62 63 static int scmi_dev_probe(struct device *dev) 64 { 65 struct scmi_driver *scmi_drv = to_scmi_driver(dev->driver); 66 struct scmi_device *scmi_dev = to_scmi_dev(dev); 67 const struct scmi_device_id *id; 68 int ret; 69 70 id = scmi_dev_match_id(scmi_dev, scmi_drv); 71 if (!id) 72 return -ENODEV; 73 74 if (!scmi_dev->handle) 75 return -EPROBE_DEFER; 76 77 ret = scmi_protocol_init(scmi_dev->protocol_id, scmi_dev->handle); 78 if (ret) 79 return ret; 80 81 return scmi_drv->probe(scmi_dev); 82 } 83 84 static int scmi_dev_remove(struct device *dev) 85 { 86 struct scmi_driver *scmi_drv = to_scmi_driver(dev->driver); 87 struct scmi_device *scmi_dev = to_scmi_dev(dev); 88 89 if (scmi_drv->remove) 90 scmi_drv->remove(scmi_dev); 91 92 return 0; 93 } 94 95 static struct bus_type scmi_bus_type = { 96 .name = "scmi_protocol", 97 .match = scmi_dev_match, 98 .probe = scmi_dev_probe, 99 .remove = scmi_dev_remove, 100 }; 101 102 int scmi_driver_register(struct scmi_driver *driver, struct module *owner, 103 const char *mod_name) 104 { 105 int retval; 106 107 driver->driver.bus = &scmi_bus_type; 108 driver->driver.name = driver->name; 109 driver->driver.owner = owner; 110 driver->driver.mod_name = mod_name; 111 112 retval = driver_register(&driver->driver); 113 if (!retval) 114 pr_debug("registered new scmi driver %s\n", driver->name); 115 116 return retval; 117 } 118 EXPORT_SYMBOL_GPL(scmi_driver_register); 119 120 void scmi_driver_unregister(struct scmi_driver *driver) 121 { 122 driver_unregister(&driver->driver); 123 } 124 EXPORT_SYMBOL_GPL(scmi_driver_unregister); 125 126 static void scmi_device_release(struct device *dev) 127 { 128 kfree(to_scmi_dev(dev)); 129 } 130 131 struct scmi_device * 132 scmi_device_create(struct device_node *np, struct device *parent, int protocol, 133 const char *name) 134 { 135 int id, retval; 136 struct scmi_device *scmi_dev; 137 138 scmi_dev = kzalloc(sizeof(*scmi_dev), GFP_KERNEL); 139 if (!scmi_dev) 140 return NULL; 141 142 scmi_dev->name = kstrdup_const(name ?: "unknown", GFP_KERNEL); 143 if (!scmi_dev->name) { 144 kfree(scmi_dev); 145 return NULL; 146 } 147 148 id = ida_simple_get(&scmi_bus_id, 1, 0, GFP_KERNEL); 149 if (id < 0) { 150 kfree_const(scmi_dev->name); 151 kfree(scmi_dev); 152 return NULL; 153 } 154 155 scmi_dev->id = id; 156 scmi_dev->protocol_id = protocol; 157 scmi_dev->dev.parent = parent; 158 scmi_dev->dev.of_node = np; 159 scmi_dev->dev.bus = &scmi_bus_type; 160 scmi_dev->dev.release = scmi_device_release; 161 dev_set_name(&scmi_dev->dev, "scmi_dev.%d", id); 162 163 retval = device_register(&scmi_dev->dev); 164 if (retval) 165 goto put_dev; 166 167 return scmi_dev; 168 put_dev: 169 kfree_const(scmi_dev->name); 170 put_device(&scmi_dev->dev); 171 ida_simple_remove(&scmi_bus_id, id); 172 return NULL; 173 } 174 175 void scmi_device_destroy(struct scmi_device *scmi_dev) 176 { 177 kfree_const(scmi_dev->name); 178 scmi_handle_put(scmi_dev->handle); 179 ida_simple_remove(&scmi_bus_id, scmi_dev->id); 180 device_unregister(&scmi_dev->dev); 181 } 182 183 void scmi_set_handle(struct scmi_device *scmi_dev) 184 { 185 scmi_dev->handle = scmi_handle_get(&scmi_dev->dev); 186 } 187 188 int scmi_protocol_register(int protocol_id, scmi_prot_init_fn_t fn) 189 { 190 int ret; 191 192 spin_lock(&protocol_lock); 193 ret = idr_alloc(&scmi_protocols, fn, protocol_id, protocol_id + 1, 194 GFP_ATOMIC); 195 spin_unlock(&protocol_lock); 196 if (ret != protocol_id) 197 pr_err("unable to allocate SCMI idr slot, err %d\n", ret); 198 199 return ret; 200 } 201 EXPORT_SYMBOL_GPL(scmi_protocol_register); 202 203 void scmi_protocol_unregister(int protocol_id) 204 { 205 spin_lock(&protocol_lock); 206 idr_remove(&scmi_protocols, protocol_id); 207 spin_unlock(&protocol_lock); 208 } 209 EXPORT_SYMBOL_GPL(scmi_protocol_unregister); 210 211 static int __scmi_devices_unregister(struct device *dev, void *data) 212 { 213 struct scmi_device *scmi_dev = to_scmi_dev(dev); 214 215 scmi_device_destroy(scmi_dev); 216 return 0; 217 } 218 219 static void scmi_devices_unregister(void) 220 { 221 bus_for_each_dev(&scmi_bus_type, NULL, NULL, __scmi_devices_unregister); 222 } 223 224 static int __init scmi_bus_init(void) 225 { 226 int retval; 227 228 retval = bus_register(&scmi_bus_type); 229 if (retval) 230 pr_err("scmi protocol bus register failed (%d)\n", retval); 231 232 return retval; 233 } 234 subsys_initcall(scmi_bus_init); 235 236 static void __exit scmi_bus_exit(void) 237 { 238 scmi_devices_unregister(); 239 bus_unregister(&scmi_bus_type); 240 ida_destroy(&scmi_bus_id); 241 } 242 module_exit(scmi_bus_exit); 243