drivers/staging/ozwpan/ozcdev.c

   1 /* -----------------------------------------------------------------------------
   2  * Copyright (c) 2011 Ozmo Inc
   3  * Released under the GNU General Public License Version 2 (GPLv2).
   4  * -----------------------------------------------------------------------------
   5  */
   6 #include <linux/module.h>
   7 #include <linux/fs.h>
   8 #include <linux/cdev.h>
   9 #include <linux/uaccess.h>
  10 #include <linux/netdevice.h>
  11 #include <linux/etherdevice.h>
  12 #include <linux/poll.h>
  13 #include <linux/sched.h>
  14 #include "ozconfig.h"
  15 #include "ozprotocol.h"
  16 #include "oztrace.h"
  17 #include "ozappif.h"
  18 #include "ozeltbuf.h"
  19 #include "ozpd.h"
  20 #include "ozproto.h"
  21 #include "ozcdev.h"
  22 /*------------------------------------------------------------------------------
  23  */
  24 #define OZ_RD_BUF_SZ    256
  25 struct oz_cdev {
  26         dev_t devnum;
  27         struct cdev cdev;
  28         wait_queue_head_t rdq;
  29         spinlock_t lock;
  30         u8 active_addr[ETH_ALEN];
  31         struct oz_pd *active_pd;
  32 };
  33
  34 /* Per PD context for the serial service stored in the PD. */
  35 struct oz_serial_ctx {
  36         atomic_t ref_count;
  37         u8 tx_seq_num;
  38         u8 rx_seq_num;
  39         u8 rd_buf[OZ_RD_BUF_SZ];
  40         int rd_in;
  41         int rd_out;
  42 };
  43 /*------------------------------------------------------------------------------
  44  */
  45 static struct oz_cdev g_cdev;
  46 static struct class *g_oz_class;
  47 /*------------------------------------------------------------------------------
  48  * Context: process and softirq
  49  */
  50 static struct oz_serial_ctx *oz_cdev_claim_ctx(struct oz_pd *pd)
  51 {
  52         struct oz_serial_ctx *ctx;
  53         spin_lock_bh(&pd->app_lock[OZ_APPID_SERIAL-1]);
  54         ctx = (struct oz_serial_ctx *)pd->app_ctx[OZ_APPID_SERIAL-1];
  55         if (ctx)
  56                 atomic_inc(&ctx->ref_count);
  57         spin_unlock_bh(&pd->app_lock[OZ_APPID_SERIAL-1]);
  58         return ctx;
  59 }
  60 /*------------------------------------------------------------------------------
  61  * Context: softirq or process
  62  */
  63 static void oz_cdev_release_ctx(struct oz_serial_ctx *ctx)
  64 {
  65         if (atomic_dec_and_test(&ctx->ref_count)) {
  66                 oz_trace("Dealloc serial context.\n");
  67                 kfree(ctx);
  68         }
  69 }
  70 /*------------------------------------------------------------------------------
  71  * Context: process
  72  */
  73 static int oz_cdev_open(struct inode *inode, struct file *filp)
  74 {
  75         struct oz_cdev *dev;
  76         oz_trace("oz_cdev_open()\n");
  77         oz_trace("major = %d minor = %d\n", imajor(inode), iminor(inode));
  78         dev = container_of(inode->i_cdev, struct oz_cdev, cdev);
  79         filp->private_data = dev;
  80         return 0;
  81 }
  82 /*------------------------------------------------------------------------------
  83  * Context: process
  84  */
  85 static int oz_cdev_release(struct inode *inode, struct file *filp)
  86 {
  87         oz_trace("oz_cdev_release()\n");
  88         return 0;
  89 }
  90 /*------------------------------------------------------------------------------
  91  * Context: process
  92  */
  93 static ssize_t oz_cdev_read(struct file *filp, char __user *buf, size_t count,
  94                 loff_t *fpos)
  95 {
  96         int n;
  97         int ix;
  98
  99         struct oz_pd *pd;
 100         struct oz_serial_ctx *ctx;
 101
 102         spin_lock_bh(&g_cdev.lock);
 103         pd = g_cdev.active_pd;
 104         if (pd)
 105                 oz_pd_get(pd);
 106         spin_unlock_bh(&g_cdev.lock);
 107         if (pd == NULL)
 108                 return -1;
 109         ctx = oz_cdev_claim_ctx(pd);
 110         if (ctx == NULL)
 111                 goto out2;
 112         n = ctx->rd_in - ctx->rd_out;
 113         if (n < 0)
 114                 n += OZ_RD_BUF_SZ;
 115         if (count > n)
 116                 count = n;
 117         ix = ctx->rd_out;
 118         n = OZ_RD_BUF_SZ - ix;
 119         if (n > count)
 120                 n = count;
 121         if (copy_to_user(buf, &ctx->rd_buf[ix], n)) {
 122                 count = 0;
 123                 goto out1;
 124         }
 125         ix += n;
 126         if (ix == OZ_RD_BUF_SZ)
 127                 ix = 0;
 128         if (n < count) {
 129                 if (copy_to_user(&buf[n], ctx->rd_buf, count-n)) {
 130                         count = 0;
 131                         goto out1;
 132                 }
 133                 ix = count-n;
 134         }
 135         ctx->rd_out = ix;
 136 out1:
 137         oz_cdev_release_ctx(ctx);
 138 out2:
 139         oz_pd_put(pd);
 140         return count;
 141 }
 142 /*------------------------------------------------------------------------------
 143  * Context: process
 144  */
 145 static ssize_t oz_cdev_write(struct file *filp, const char __user *buf,
 146                 size_t count, loff_t *fpos)
 147 {
 148         struct oz_pd *pd;
 149         struct oz_elt_buf *eb;
 150         struct oz_elt_info *ei;
 151         struct oz_elt *elt;
 152         struct oz_app_hdr *app_hdr;
 153         struct oz_serial_ctx *ctx;
 154
 155         spin_lock_bh(&g_cdev.lock);
 156         pd = g_cdev.active_pd;
 157         if (pd)
 158                 oz_pd_get(pd);
 159         spin_unlock_bh(&g_cdev.lock);
 160         if (pd == NULL)
 161                 return -1;
 162         eb = &pd->elt_buff;
 163         ei = oz_elt_info_alloc(eb);
 164         if (ei == NULL) {
 165                 count = 0;
 166                 goto out;
 167         }
 168         elt = (struct oz_elt *)ei->data;
 169         app_hdr = (struct oz_app_hdr *)(elt+1);
 170         elt->length = sizeof(struct oz_app_hdr) + count;
 171         elt->type = OZ_ELT_APP_DATA;
 172         ei->app_id = OZ_APPID_SERIAL;
 173         ei->length = elt->length + sizeof(struct oz_elt);
 174         app_hdr->app_id = OZ_APPID_SERIAL;
 175         if (copy_from_user(app_hdr+1, buf, count))
 176                 goto out;
 177         spin_lock_bh(&pd->app_lock[OZ_APPID_USB-1]);
 178         ctx = (struct oz_serial_ctx *)pd->app_ctx[OZ_APPID_SERIAL-1];
 179         if (ctx) {
 180                 app_hdr->elt_seq_num = ctx->tx_seq_num++;
 181                 if (ctx->tx_seq_num == 0)
 182                         ctx->tx_seq_num = 1;
 183                 spin_lock(&eb->lock);
 184                 if (oz_queue_elt_info(eb, 0, 0, ei) == 0)
 185                         ei = NULL;
 186                 spin_unlock(&eb->lock);
 187         }
 188         spin_unlock_bh(&pd->app_lock[OZ_APPID_USB-1]);
 189 out:
 190         if (ei) {
 191                 count = 0;
 192                 spin_lock_bh(&eb->lock);
 193                 oz_elt_info_free(eb, ei);
 194                 spin_unlock_bh(&eb->lock);
 195         }
 196         oz_pd_put(pd);
 197         return count;
 198 }
 199 /*------------------------------------------------------------------------------
 200  * Context: process
 201  */
 202 static int oz_set_active_pd(const u8 *addr)
 203 {
 204         int rc = 0;
 205         struct oz_pd *pd;
 206         struct oz_pd *old_pd;
 207         pd = oz_pd_find(addr);
 208         if (pd) {
 209                 spin_lock_bh(&g_cdev.lock);
 210                 memcpy(g_cdev.active_addr, addr, ETH_ALEN);
 211                 old_pd = g_cdev.active_pd;
 212                 g_cdev.active_pd = pd;
 213                 spin_unlock_bh(&g_cdev.lock);
 214                 if (old_pd)
 215                         oz_pd_put(old_pd);
 216         } else {
 217                 if (is_zero_ether_addr(addr)) {
 218                         spin_lock_bh(&g_cdev.lock);
 219                         pd = g_cdev.active_pd;
 220                         g_cdev.active_pd = NULL;
 221                         memset(g_cdev.active_addr, 0,
 222                                 sizeof(g_cdev.active_addr));
 223                         spin_unlock_bh(&g_cdev.lock);
 224                         if (pd)
 225                                 oz_pd_put(pd);
 226                 } else {
 227                         rc = -1;
 228                 }
 229         }
 230         return rc;
 231 }
 232 /*------------------------------------------------------------------------------
 233  * Context: process
 234  */
 235 static long oz_cdev_ioctl(struct file *filp, unsigned int cmd,
 236                           unsigned long arg)
 237 {
 238         int rc = 0;
 239         if (_IOC_TYPE(cmd) != OZ_IOCTL_MAGIC)
 240                 return -ENOTTY;
 241         if (_IOC_NR(cmd) > OZ_IOCTL_MAX)
 242                 return -ENOTTY;
 243         if (_IOC_DIR(cmd) & _IOC_READ)
 244                 rc = !access_ok(VERIFY_WRITE, (void __user *)arg,
 245                         _IOC_SIZE(cmd));
 246         else if (_IOC_DIR(cmd) & _IOC_WRITE)
 247                 rc = !access_ok(VERIFY_READ, (void __user *)arg,
 248                         _IOC_SIZE(cmd));
 249         if (rc)
 250                 return -EFAULT;
 251         switch (cmd) {
 252         case OZ_IOCTL_GET_PD_LIST: {
 253                         struct oz_pd_list list;
 254                         oz_trace("OZ_IOCTL_GET_PD_LIST\n");
 255                         memset(&list, 0, sizeof(list));
 256                         list.count = oz_get_pd_list(list.addr, OZ_MAX_PDS);
 257                         if (copy_to_user((void __user *)arg, &list,
 258                                 sizeof(list)))
 259                                 return -EFAULT;
 260                 }
 261                 break;
 262         case OZ_IOCTL_SET_ACTIVE_PD: {
 263                         u8 addr[ETH_ALEN];
 264                         oz_trace("OZ_IOCTL_SET_ACTIVE_PD\n");
 265                         if (copy_from_user(addr, (void __user *)arg, ETH_ALEN))
 266                                 return -EFAULT;
 267                         rc = oz_set_active_pd(addr);
 268                 }
 269                 break;
 270         case OZ_IOCTL_GET_ACTIVE_PD: {
 271                         u8 addr[ETH_ALEN];
 272                         oz_trace("OZ_IOCTL_GET_ACTIVE_PD\n");
 273                         spin_lock_bh(&g_cdev.lock);
 274                         memcpy(addr, g_cdev.active_addr, ETH_ALEN);
 275                         spin_unlock_bh(&g_cdev.lock);
 276                         if (copy_to_user((void __user *)arg, addr, ETH_ALEN))
 277                                 return -EFAULT;
 278                 }
 279                 break;
 280         case OZ_IOCTL_ADD_BINDING:
 281         case OZ_IOCTL_REMOVE_BINDING: {
 282                         struct oz_binding_info b;
 283                         if (copy_from_user(&b, (void __user *)arg,
 284                                 sizeof(struct oz_binding_info))) {
 285                                 return -EFAULT;
 286                         }
 287                         /* Make sure name is null terminated. */
 288                         b.name[OZ_MAX_BINDING_LEN-1] = 0;
 289                         if (cmd == OZ_IOCTL_ADD_BINDING)
 290                                 oz_binding_add(b.name);
 291                         else
 292                                 oz_binding_remove(b.name);
 293                 }
 294                 break;
 295         }
 296         return rc;
 297 }
 298 /*------------------------------------------------------------------------------
 299  * Context: process
 300  */
 301 static unsigned int oz_cdev_poll(struct file *filp, poll_table *wait)
 302 {
 303         unsigned int ret = 0;
 304         struct oz_cdev *dev = filp->private_data;
 305         oz_trace("Poll called wait = %p\n", wait);
 306         spin_lock_bh(&dev->lock);
 307         if (dev->active_pd) {
 308                 struct oz_serial_ctx *ctx = oz_cdev_claim_ctx(dev->active_pd);
 309                 if (ctx) {
 310                         if (ctx->rd_in != ctx->rd_out)
 311                                 ret |= POLLIN | POLLRDNORM;
 312                         oz_cdev_release_ctx(ctx);
 313                 }
 314         }
 315         spin_unlock_bh(&dev->lock);
 316         if (wait)
 317                 poll_wait(filp, &dev->rdq, wait);
 318         return ret;
 319 }
 320 /*------------------------------------------------------------------------------
 321  */
 322 static const struct file_operations oz_fops = {
 323         .owner =        THIS_MODULE,
 324         .open =         oz_cdev_open,
 325         .release =      oz_cdev_release,
 326         .read =         oz_cdev_read,
 327         .write =        oz_cdev_write,
 328         .unlocked_ioctl = oz_cdev_ioctl,
 329         .poll =         oz_cdev_poll
 330 };
 331 /*------------------------------------------------------------------------------
 332  * Context: process
 333  */
 334 int oz_cdev_register(void)
 335 {
 336         int err;
 337         struct device *dev;
 338         memset(&g_cdev, 0, sizeof(g_cdev));
 339         err = alloc_chrdev_region(&g_cdev.devnum, 0, 1, "ozwpan");
 340         if (err < 0)
 341                 goto out3;
 342         oz_trace("Alloc dev number %d:%d\n", MAJOR(g_cdev.devnum),
 343                         MINOR(g_cdev.devnum));
 344         cdev_init(&g_cdev.cdev, &oz_fops);
 345         g_cdev.cdev.owner = THIS_MODULE;
 346         g_cdev.cdev.ops = &oz_fops;
 347         spin_lock_init(&g_cdev.lock);
 348         init_waitqueue_head(&g_cdev.rdq);
 349         err = cdev_add(&g_cdev.cdev, g_cdev.devnum, 1);
 350         if (err < 0) {
 351                 oz_trace("Failed to add cdev\n");
 352                 goto out2;
 353         }
 354         g_oz_class = class_create(THIS_MODULE, "ozmo_wpan");
 355         if (IS_ERR(g_oz_class)) {
 356                 oz_trace("Failed to register ozmo_wpan class\n");
 357                 err = PTR_ERR(g_oz_class);
 358                 goto out1;
 359         }
 360         dev = device_create(g_oz_class, NULL, g_cdev.devnum, NULL, "ozwpan");
 361         if (IS_ERR(dev)) {
 362                 oz_trace("Failed to create sysfs entry for cdev\n");
 363                 err = PTR_ERR(dev);
 364                 goto out1;
 365         }
 366         return 0;
 367 out1:
 368         cdev_del(&g_cdev.cdev);
 369 out2:
 370         unregister_chrdev_region(g_cdev.devnum, 1);
 371 out3:
 372         return err;
 373 }
 374 /*------------------------------------------------------------------------------
 375  * Context: process
 376  */
 377 int oz_cdev_deregister(void)
 378 {
 379         cdev_del(&g_cdev.cdev);
 380         unregister_chrdev_region(g_cdev.devnum, 1);
 381         if (g_oz_class) {
 382                 device_destroy(g_oz_class, g_cdev.devnum);
 383                 class_destroy(g_oz_class);
 384         }
 385         return 0;
 386 }
 387 /*------------------------------------------------------------------------------
 388  * Context: process
 389  */
 390 int oz_cdev_init(void)
 391 {
 392         oz_app_enable(OZ_APPID_SERIAL, 1);
 393         return 0;
 394 }
 395 /*------------------------------------------------------------------------------
 396  * Context: process
 397  */
 398 void oz_cdev_term(void)
 399 {
 400         oz_app_enable(OZ_APPID_SERIAL, 0);
 401 }
 402 /*------------------------------------------------------------------------------
 403  * Context: softirq-serialized
 404  */
 405 int oz_cdev_start(struct oz_pd *pd, int resume)
 406 {
 407         struct oz_serial_ctx *ctx;
 408         struct oz_serial_ctx *old_ctx;
 409         if (resume) {
 410                 oz_trace("Serial service resumed.\n");
 411                 return 0;
 412         }
 413         ctx = kzalloc(sizeof(struct oz_serial_ctx), GFP_ATOMIC);
 414         if (ctx == NULL)
 415                 return -ENOMEM;
 416         atomic_set(&ctx->ref_count, 1);
 417         ctx->tx_seq_num = 1;
 418         spin_lock_bh(&pd->app_lock[OZ_APPID_SERIAL-1]);
 419         old_ctx = pd->app_ctx[OZ_APPID_SERIAL-1];
 420         if (old_ctx) {
 421                 spin_unlock_bh(&pd->app_lock[OZ_APPID_SERIAL-1]);
 422                 kfree(ctx);
 423         } else {
 424                 pd->app_ctx[OZ_APPID_SERIAL-1] = ctx;
 425                 spin_unlock_bh(&pd->app_lock[OZ_APPID_SERIAL-1]);
 426         }
 427         spin_lock(&g_cdev.lock);
 428         if ((g_cdev.active_pd == NULL) &&
 429                 (memcmp(pd->mac_addr, g_cdev.active_addr, ETH_ALEN) == 0)) {
 430                 oz_pd_get(pd);
 431                 g_cdev.active_pd = pd;
 432                 oz_trace("Active PD arrived.\n");
 433         }
 434         spin_unlock(&g_cdev.lock);
 435         oz_trace("Serial service started.\n");
 436         return 0;
 437 }
 438 /*------------------------------------------------------------------------------
 439  * Context: softirq or process
 440  */
 441 void oz_cdev_stop(struct oz_pd *pd, int pause)
 442 {
 443         struct oz_serial_ctx *ctx;
 444         if (pause) {
 445                 oz_trace("Serial service paused.\n");
 446                 return;
 447         }
 448         spin_lock_bh(&pd->app_lock[OZ_APPID_SERIAL-1]);
 449         ctx = (struct oz_serial_ctx *)pd->app_ctx[OZ_APPID_SERIAL-1];
 450         pd->app_ctx[OZ_APPID_SERIAL-1] = NULL;
 451         spin_unlock_bh(&pd->app_lock[OZ_APPID_SERIAL-1]);
 452         if (ctx)
 453                 oz_cdev_release_ctx(ctx);
 454         spin_lock(&g_cdev.lock);
 455         if (pd == g_cdev.active_pd)
 456                 g_cdev.active_pd = NULL;
 457         else
 458                 pd = NULL;
 459         spin_unlock(&g_cdev.lock);
 460         if (pd) {
 461                 oz_pd_put(pd);
 462                 oz_trace("Active PD departed.\n");
 463         }
 464         oz_trace("Serial service stopped.\n");
 465 }
 466 /*------------------------------------------------------------------------------
 467  * Context: softirq-serialized
 468  */
 469 void oz_cdev_rx(struct oz_pd *pd, struct oz_elt *elt)
 470 {
 471         struct oz_serial_ctx *ctx;
 472         struct oz_app_hdr *app_hdr;
 473         u8 *data;
 474         int len;
 475         int space;
 476         int copy_sz;
 477         int ix;
 478
 479         ctx = oz_cdev_claim_ctx(pd);
 480         if (ctx == NULL) {
 481                 oz_trace("Cannot claim serial context.\n");
 482                 return;
 483         }
 484
 485         app_hdr = (struct oz_app_hdr *)(elt+1);
 486         /* If sequence number is non-zero then check it is not a duplicate.
 487          */
 488         if (app_hdr->elt_seq_num != 0) {
 489                 if (((ctx->rx_seq_num - app_hdr->elt_seq_num) & 0x80) == 0) {
 490                         /* Reject duplicate element. */
 491                         oz_trace("Duplicate element:%02x %02x\n",
 492                                 app_hdr->elt_seq_num, ctx->rx_seq_num);
 493                         goto out;
 494                 }
 495         }
 496         ctx->rx_seq_num = app_hdr->elt_seq_num;
 497         len = elt->length - sizeof(struct oz_app_hdr);
 498         data = ((u8 *)(elt+1)) + sizeof(struct oz_app_hdr);
 499         if (len <= 0)
 500                 goto out;
 501         space = ctx->rd_out - ctx->rd_in - 1;
 502         if (space < 0)
 503                 space += OZ_RD_BUF_SZ;
 504         if (len > space) {
 505                 oz_trace("Not enough space:%d %d\n", len, space);
 506                 len = space;
 507         }
 508         ix = ctx->rd_in;
 509         copy_sz = OZ_RD_BUF_SZ - ix;
 510         if (copy_sz > len)
 511                 copy_sz = len;
 512         memcpy(&ctx->rd_buf[ix], data, copy_sz);
 513         len -= copy_sz;
 514         ix += copy_sz;
 515         if (ix == OZ_RD_BUF_SZ)
 516                 ix = 0;
 517         if (len) {
 518                 memcpy(ctx->rd_buf, data+copy_sz, len);
 519                 ix = len;
 520         }
 521         ctx->rd_in = ix;
 522         wake_up(&g_cdev.rdq);
 523 out:
 524         oz_cdev_release_ctx(ctx);
 525 }