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 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);