drivers/s390/net/smsgiucv.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * IUCV special message driver
   4  *
   5  * Copyright IBM Corp. 2003, 2009
   6  *
   7  * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
   8  */
   9
  10 #include <linux/module.h>
  11 #include <linux/init.h>
  12 #include <linux/errno.h>
  13 #include <linux/device.h>
  14 #include <linux/slab.h>
  15 #include <net/iucv/iucv.h>
  16 #include <asm/cpcmd.h>
  17 #include <asm/ebcdic.h>
  18 #include "smsgiucv.h"
  19
  20 struct smsg_callback {
  21         struct list_head list;
  22         const char *prefix;
  23         int len;
  24         void (*callback)(const char *from, char *str);
  25 };
  26
  27 MODULE_AUTHOR
  28    ("(C) 2003 IBM Corporation by Martin Schwidefsky (schwidefsky@de.ibm.com)");
  29 MODULE_DESCRIPTION ("Linux for S/390 IUCV special message driver");
  30
  31 static struct iucv_path *smsg_path;
  32 /* dummy device used as trigger for PM functions */
  33 static struct device *smsg_dev;
  34
  35 static DEFINE_SPINLOCK(smsg_list_lock);
  36 static LIST_HEAD(smsg_list);
  37 static int iucv_path_connected;
  38
  39 static int smsg_path_pending(struct iucv_path *, u8 *, u8 *);
  40 static void smsg_message_pending(struct iucv_path *, struct iucv_message *);
  41
  42 static struct iucv_handler smsg_handler = {
  43         .path_pending    = smsg_path_pending,
  44         .message_pending = smsg_message_pending,
  45 };
  46
  47 static int smsg_path_pending(struct iucv_path *path, u8 *ipvmid, u8 *ipuser)
  48 {
  49         if (strncmp(ipvmid, "*MSG    ", 8) != 0)
  50                 return -EINVAL;
  51         /* Path pending from *MSG. */
  52         return iucv_path_accept(path, &smsg_handler, "SMSGIUCV        ", NULL);
  53 }
  54
  55 static void smsg_message_pending(struct iucv_path *path,
  56                                  struct iucv_message *msg)
  57 {
  58         struct smsg_callback *cb;
  59         unsigned char *buffer;
  60         unsigned char sender[9];
  61         int rc, i;
  62
  63         buffer = kmalloc(msg->length + 1, GFP_ATOMIC | GFP_DMA);
  64         if (!buffer) {
  65                 iucv_message_reject(path, msg);
  66                 return;
  67         }
  68         rc = iucv_message_receive(path, msg, 0, buffer, msg->length, NULL);
  69         if (rc == 0) {
  70                 buffer[msg->length] = 0;
  71                 EBCASC(buffer, msg->length);
  72                 memcpy(sender, buffer, 8);
  73                 sender[8] = 0;
  74                 /* Remove trailing whitespace from the sender name. */
  75                 for (i = 7; i >= 0; i--) {
  76                         if (sender[i] != ' ' && sender[i] != '\t')
  77                                 break;
  78                         sender[i] = 0;
  79                 }
  80                 spin_lock(&smsg_list_lock);
  81                 list_for_each_entry(cb, &smsg_list, list)
  82                         if (strncmp(buffer + 8, cb->prefix, cb->len) == 0) {
  83                                 cb->callback(sender, buffer + 8);
  84                                 break;
  85                         }
  86                 spin_unlock(&smsg_list_lock);
  87         }
  88         kfree(buffer);
  89 }
  90
  91 int smsg_register_callback(const char *prefix,
  92                            void (*callback)(const char *from, char *str))
  93 {
  94         struct smsg_callback *cb;
  95
  96         cb = kmalloc(sizeof(struct smsg_callback), GFP_KERNEL);
  97         if (!cb)
  98                 return -ENOMEM;
  99         cb->prefix = prefix;
 100         cb->len = strlen(prefix);
 101         cb->callback = callback;
 102         spin_lock_bh(&smsg_list_lock);
 103         list_add_tail(&cb->list, &smsg_list);
 104         spin_unlock_bh(&smsg_list_lock);
 105         return 0;
 106 }
 107
 108 void smsg_unregister_callback(const char *prefix,
 109                               void (*callback)(const char *from,
 110                                                char *str))
 111 {
 112         struct smsg_callback *cb, *tmp;
 113
 114         spin_lock_bh(&smsg_list_lock);
 115         cb = NULL;
 116         list_for_each_entry(tmp, &smsg_list, list)
 117                 if (tmp->callback == callback &&
 118                     strcmp(tmp->prefix, prefix) == 0) {
 119                         cb = tmp;
 120                         list_del(&cb->list);
 121                         break;
 122                 }
 123         spin_unlock_bh(&smsg_list_lock);
 124         kfree(cb);
 125 }
 126
 127 static int smsg_pm_freeze(struct device *dev)
 128 {
 129 #ifdef CONFIG_PM_DEBUG
 130         printk(KERN_WARNING "smsg_pm_freeze\n");
 131 #endif
 132         if (smsg_path && iucv_path_connected) {
 133                 iucv_path_sever(smsg_path, NULL);
 134                 iucv_path_connected = 0;
 135         }
 136         return 0;
 137 }
 138
 139 static int smsg_pm_restore_thaw(struct device *dev)
 140 {
 141         int rc;
 142
 143 #ifdef CONFIG_PM_DEBUG
 144         printk(KERN_WARNING "smsg_pm_restore_thaw\n");
 145 #endif
 146         if (smsg_path && !iucv_path_connected) {
 147                 memset(smsg_path, 0, sizeof(*smsg_path));
 148                 smsg_path->msglim = 255;
 149                 smsg_path->flags = 0;
 150                 rc = iucv_path_connect(smsg_path, &smsg_handler, "*MSG    ",
 151                                        NULL, NULL, NULL);
 152 #ifdef CONFIG_PM_DEBUG
 153                 if (rc)
 154                         printk(KERN_ERR
 155                                "iucv_path_connect returned with rc %i\n", rc);
 156 #endif
 157                 if (!rc)
 158                         iucv_path_connected = 1;
 159                 cpcmd("SET SMSG IUCV", NULL, 0, NULL);
 160         }
 161         return 0;
 162 }
 163
 164 static const struct dev_pm_ops smsg_pm_ops = {
 165         .freeze = smsg_pm_freeze,
 166         .thaw = smsg_pm_restore_thaw,
 167         .restore = smsg_pm_restore_thaw,
 168 };
 169
 170 static struct device_driver smsg_driver = {
 171         .owner = THIS_MODULE,
 172         .name = SMSGIUCV_DRV_NAME,
 173         .bus  = &iucv_bus,
 174         .pm = &smsg_pm_ops,
 175 };
 176
 177 static void __exit smsg_exit(void)
 178 {
 179         cpcmd("SET SMSG OFF", NULL, 0, NULL);
 180         device_unregister(smsg_dev);
 181         iucv_unregister(&smsg_handler, 1);
 182         driver_unregister(&smsg_driver);
 183 }
 184
 185 static int __init smsg_init(void)
 186 {
 187         int rc;
 188
 189         if (!MACHINE_IS_VM) {
 190                 rc = -EPROTONOSUPPORT;
 191                 goto out;
 192         }
 193         rc = driver_register(&smsg_driver);
 194         if (rc != 0)
 195                 goto out;
 196         rc = iucv_register(&smsg_handler, 1);
 197         if (rc)
 198                 goto out_driver;
 199         smsg_path = iucv_path_alloc(255, 0, GFP_KERNEL);
 200         if (!smsg_path) {
 201                 rc = -ENOMEM;
 202                 goto out_register;
 203         }
 204         rc = iucv_path_connect(smsg_path, &smsg_handler, "*MSG    ",
 205                                NULL, NULL, NULL);
 206         if (rc)
 207                 goto out_free_path;
 208         else
 209                 iucv_path_connected = 1;
 210         smsg_dev = kzalloc(sizeof(struct device), GFP_KERNEL);
 211         if (!smsg_dev) {
 212                 rc = -ENOMEM;
 213                 goto out_free_path;
 214         }
 215         dev_set_name(smsg_dev, "smsg_iucv");
 216         smsg_dev->bus = &iucv_bus;
 217         smsg_dev->parent = iucv_root;
 218         smsg_dev->release = (void (*)(struct device *))kfree;
 219         smsg_dev->driver = &smsg_driver;
 220         rc = device_register(smsg_dev);
 221         if (rc)
 222                 goto out_put;
 223
 224         cpcmd("SET SMSG IUCV", NULL, 0, NULL);
 225         return 0;
 226
 227 out_put:
 228         put_device(smsg_dev);
 229 out_free_path:
 230         iucv_path_free(smsg_path);
 231         smsg_path = NULL;
 232 out_register:
 233         iucv_unregister(&smsg_handler, 1);
 234 out_driver:
 235         driver_unregister(&smsg_driver);
 236 out:
 237         return rc;
 238 }
 239
 240 module_init(smsg_init);
 241 module_exit(smsg_exit);
 242 MODULE_LICENSE("GPL");
 243
 244 EXPORT_SYMBOL(smsg_register_callback);
 245 EXPORT_SYMBOL(smsg_unregister_callback);