drivers/firmware/arm_scmi/bus.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * System Control and Management Interface (SCMI) Message Protocol bus layer
   4  *
   5  * Copyright (C) 2018-2021 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_match_by_id_table(struct device *dev, void *data)
  55 {
  56         struct scmi_device *sdev = to_scmi_dev(dev);
  57         struct scmi_device_id *id_table = data;
  58
  59         return sdev->protocol_id == id_table->protocol_id &&
  60                 !strcmp(sdev->name, id_table->name);
  61 }
  62
  63 struct scmi_device *scmi_child_dev_find(struct device *parent,
  64                                         int prot_id, const char *name)
  65 {
  66         struct scmi_device_id id_table;
  67         struct device *dev;
  68
  69         id_table.protocol_id = prot_id;
  70         id_table.name = name;
  71
  72         dev = device_find_child(parent, &id_table, scmi_match_by_id_table);
  73         if (!dev)
  74                 return NULL;
  75
  76         return to_scmi_dev(dev);
  77 }
  78
  79 const struct scmi_protocol *scmi_protocol_get(int protocol_id)
  80 {
  81         const struct scmi_protocol *proto;
  82
  83         proto = idr_find(&scmi_protocols, protocol_id);
  84         if (!proto || !try_module_get(proto->owner)) {
  85                 pr_warn("SCMI Protocol 0x%x not found!\n", protocol_id);
  86                 return NULL;
  87         }
  88
  89         pr_debug("Found SCMI Protocol 0x%x\n", protocol_id);
  90
  91         return proto;
  92 }
  93
  94 void scmi_protocol_put(int protocol_id)
  95 {
  96         const struct scmi_protocol *proto;
  97
  98         proto = idr_find(&scmi_protocols, protocol_id);
  99         if (proto)
 100                 module_put(proto->owner);
 101 }
 102
 103 static int scmi_dev_probe(struct device *dev)
 104 {
 105         struct scmi_driver *scmi_drv = to_scmi_driver(dev->driver);
 106         struct scmi_device *scmi_dev = to_scmi_dev(dev);
 107
 108         if (!scmi_dev->handle)
 109                 return -EPROBE_DEFER;
 110
 111         return scmi_drv->probe(scmi_dev);
 112 }
 113
 114 static void scmi_dev_remove(struct device *dev)
 115 {
 116         struct scmi_driver *scmi_drv = to_scmi_driver(dev->driver);
 117         struct scmi_device *scmi_dev = to_scmi_dev(dev);
 118
 119         if (scmi_drv->remove)
 120                 scmi_drv->remove(scmi_dev);
 121 }
 122
 123 static struct bus_type scmi_bus_type = {
 124         .name = "scmi_protocol",
 125         .match = scmi_dev_match,
 126         .probe = scmi_dev_probe,
 127         .remove = scmi_dev_remove,
 128 };
 129
 130 int scmi_driver_register(struct scmi_driver *driver, struct module *owner,
 131                          const char *mod_name)
 132 {
 133         int retval;
 134
 135         if (!driver->probe)
 136                 return -EINVAL;
 137
 138         retval = scmi_protocol_device_request(driver->id_table);
 139         if (retval)
 140                 return retval;
 141
 142         driver->driver.bus = &scmi_bus_type;
 143         driver->driver.name = driver->name;
 144         driver->driver.owner = owner;
 145         driver->driver.mod_name = mod_name;
 146
 147         retval = driver_register(&driver->driver);
 148         if (!retval)
 149                 pr_debug("registered new scmi driver %s\n", driver->name);
 150
 151         return retval;
 152 }
 153 EXPORT_SYMBOL_GPL(scmi_driver_register);
 154
 155 void scmi_driver_unregister(struct scmi_driver *driver)
 156 {
 157         driver_unregister(&driver->driver);
 158         scmi_protocol_device_unrequest(driver->id_table);
 159 }
 160 EXPORT_SYMBOL_GPL(scmi_driver_unregister);
 161
 162 static void scmi_device_release(struct device *dev)
 163 {
 164         kfree(to_scmi_dev(dev));
 165 }
 166
 167 struct scmi_device *
 168 scmi_device_create(struct device_node *np, struct device *parent, int protocol,
 169                    const char *name)
 170 {
 171         int id, retval;
 172         struct scmi_device *scmi_dev;
 173
 174         scmi_dev = kzalloc(sizeof(*scmi_dev), GFP_KERNEL);
 175         if (!scmi_dev)
 176                 return NULL;
 177
 178         scmi_dev->name = kstrdup_const(name ?: "unknown", GFP_KERNEL);
 179         if (!scmi_dev->name) {
 180                 kfree(scmi_dev);
 181                 return NULL;
 182         }
 183
 184         id = ida_simple_get(&scmi_bus_id, 1, 0, GFP_KERNEL);
 185         if (id < 0) {
 186                 kfree_const(scmi_dev->name);
 187                 kfree(scmi_dev);
 188                 return NULL;
 189         }
 190
 191         scmi_dev->id = id;
 192         scmi_dev->protocol_id = protocol;
 193         scmi_dev->dev.parent = parent;
 194         scmi_dev->dev.of_node = np;
 195         scmi_dev->dev.bus = &scmi_bus_type;
 196         scmi_dev->dev.release = scmi_device_release;
 197         dev_set_name(&scmi_dev->dev, "scmi_dev.%d", id);
 198
 199         retval = device_register(&scmi_dev->dev);
 200         if (retval)
 201                 goto put_dev;
 202
 203         return scmi_dev;
 204 put_dev:
 205         kfree_const(scmi_dev->name);
 206         put_device(&scmi_dev->dev);
 207         ida_simple_remove(&scmi_bus_id, id);
 208         return NULL;
 209 }
 210
 211 void scmi_device_destroy(struct scmi_device *scmi_dev)
 212 {
 213         kfree_const(scmi_dev->name);
 214         scmi_handle_put(scmi_dev->handle);
 215         ida_simple_remove(&scmi_bus_id, scmi_dev->id);
 216         device_unregister(&scmi_dev->dev);
 217 }
 218
 219 void scmi_set_handle(struct scmi_device *scmi_dev)
 220 {
 221         scmi_dev->handle = scmi_handle_get(&scmi_dev->dev);
 222 }
 223
 224 int scmi_protocol_register(const struct scmi_protocol *proto)
 225 {
 226         int ret;
 227
 228         if (!proto) {
 229                 pr_err("invalid protocol\n");
 230                 return -EINVAL;
 231         }
 232
 233         if (!proto->instance_init) {
 234                 pr_err("missing init for protocol 0x%x\n", proto->id);
 235                 return -EINVAL;
 236         }
 237
 238         spin_lock(&protocol_lock);
 239         ret = idr_alloc(&scmi_protocols, (void *)proto,
 240                         proto->id, proto->id + 1, GFP_ATOMIC);
 241         spin_unlock(&protocol_lock);
 242         if (ret != proto->id) {
 243                 pr_err("unable to allocate SCMI idr slot for 0x%x - err %d\n",
 244                        proto->id, ret);
 245                 return ret;
 246         }
 247
 248         pr_debug("Registered SCMI Protocol 0x%x\n", proto->id);
 249
 250         return 0;
 251 }
 252 EXPORT_SYMBOL_GPL(scmi_protocol_register);
 253
 254 void scmi_protocol_unregister(const struct scmi_protocol *proto)
 255 {
 256         spin_lock(&protocol_lock);
 257         idr_remove(&scmi_protocols, proto->id);
 258         spin_unlock(&protocol_lock);
 259
 260         pr_debug("Unregistered SCMI Protocol 0x%x\n", proto->id);
 261
 262         return;
 263 }
 264 EXPORT_SYMBOL_GPL(scmi_protocol_unregister);
 265
 266 static int __scmi_devices_unregister(struct device *dev, void *data)
 267 {
 268         struct scmi_device *scmi_dev = to_scmi_dev(dev);
 269
 270         scmi_device_destroy(scmi_dev);
 271         return 0;
 272 }
 273
 274 static void scmi_devices_unregister(void)
 275 {
 276         bus_for_each_dev(&scmi_bus_type, NULL, NULL, __scmi_devices_unregister);
 277 }
 278
 279 int __init scmi_bus_init(void)
 280 {
 281         int retval;
 282
 283         retval = bus_register(&scmi_bus_type);
 284         if (retval)
 285                 pr_err("scmi protocol bus register failed (%d)\n", retval);
 286
 287         return retval;
 288 }
 289
 290 void __exit scmi_bus_exit(void)
 291 {
 292         scmi_devices_unregister();
 293         bus_unregister(&scmi_bus_type);
 294         ida_destroy(&scmi_bus_id);
 295 }