kernel/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 "ozdbg.h"
  15 #include "ozprotocol.h"
  16 #include "ozappif.h"
  17 #include "ozeltbuf.h"
  18 #include "ozpd.h"
  19 #include "ozproto.h"
  20 #include "ozcdev.h"
  21
  22 #define OZ_RD_BUF_SZ    256
  23 struct oz_cdev {
  24         dev_t devnum;
  25         struct cdev cdev;
  26         wait_queue_head_t rdq;
  27         spinlock_t lock;
  28         u8 active_addr[ETH_ALEN];
  29         struct oz_pd *active_pd;
  30 };
  31
  32 /* Per PD context for the serial service stored in the PD. */
  33 struct oz_serial_ctx {
  34         atomic_t ref_count;
  35         u8 tx_seq_num;
  36         u8 rx_seq_num;
  37         u8 rd_buf[OZ_RD_BUF_SZ];
  38         int rd_in;
  39         int rd_out;
  40 };
  41
  42 static struct oz_cdev g_cdev;
  43 static struct class *g_oz_class;
  44
  45 /*
  46  * Context: process and softirq
  47  */
  48 static struct oz_serial_ctx *oz_cdev_claim_ctx(struct oz_pd *pd)
  49 {
  50         struct oz_serial_ctx *ctx;
  51
  52         spin_lock_bh(&pd->app_lock[OZ_APPID_SERIAL]);
  53         ctx = (struct oz_serial_ctx *) pd->app_ctx[OZ_APPID_SERIAL];
  54         if (ctx)
  55                 atomic_inc(&ctx->ref_count);
  56         spin_unlock_bh(&pd->app_lock[OZ_APPID_SERIAL]);
  57         return ctx;
  58 }
  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_dbg(ON, "Dealloc serial context\n");
  67                 kfree(ctx);
  68         }
  69 }
  70
  71 /*
  72  * Context: process
  73  */
  74 static int oz_cdev_open(struct inode *inode, struct file *filp)
  75 {
  76         struct oz_cdev *dev = container_of(inode->i_cdev, struct oz_cdev, cdev);
  77
  78         oz_dbg(ON, "major = %d minor = %d\n", imajor(inode), iminor(inode));
  79
  80         filp->private_data = dev;
  81         return 0;
  82 }
  83
  84 /*
  85  * Context: process
  86  */
  87 static int oz_cdev_release(struct inode *inode, struct file *filp)
  88 {
  89         return 0;
  90 }
  91
  92 /*
  93  * Context: process
  94  */
  95 static ssize_t oz_cdev_read(struct file *filp, char __user *buf, size_t count,
  96                 loff_t *fpos)
  97 {
  98         int n;
  99         int ix;
 100
 101         struct oz_pd *pd;
 102         struct oz_serial_ctx *ctx;
 103
 104         spin_lock_bh(&g_cdev.lock);
 105         pd = g_cdev.active_pd;
 106         if (pd)
 107                 oz_pd_get(pd);
 108         spin_unlock_bh(&g_cdev.lock);
 109         if (pd == NULL)
 110                 return -1;
 111         ctx = oz_cdev_claim_ctx(pd);
 112         if (ctx == NULL)
 113                 goto out2;
 114         n = ctx->rd_in - ctx->rd_out;
 115         if (n < 0)
 116                 n += OZ_RD_BUF_SZ;
 117         if (count > n)
 118                 count = n;
 119         ix = ctx->rd_out;
 120         n = OZ_RD_BUF_SZ - ix;
 121         if (n > count)
 122                 n = count;
 123         if (copy_to_user(buf, &ctx->rd_buf[ix], n)) {
 124                 count = 0;
 125                 goto out1;
 126         }
 127         ix += n;
 128         if (ix == OZ_RD_BUF_SZ)
 129                 ix = 0;
 130         if (n < count) {
 131                 if (copy_to_user(&buf[n], ctx->rd_buf, count-n)) {
 132                         count = 0;
 133                         goto out1;
 134                 }
 135                 ix = count-n;
 136         }
 137         ctx->rd_out = ix;
 138 out1:
 139         oz_cdev_release_ctx(ctx);
 140 out2:
 141         oz_pd_put(pd);
 142         return count;
 143 }
 144
 145 /*
 146  * Context: process
 147  */
 148 static ssize_t oz_cdev_write(struct file *filp, const char __user *buf,
 149                 size_t count, loff_t *fpos)
 150 {
 151         struct oz_pd *pd;
 152         struct oz_elt_buf *eb;
 153         struct oz_elt_info *ei;
 154         struct oz_elt *elt;
 155         struct oz_app_hdr *app_hdr;
 156         struct oz_serial_ctx *ctx;
 157
 158         if (count > sizeof(ei->data) - sizeof(*elt) - sizeof(*app_hdr))
 159                 return -EINVAL;
 160
 161         spin_lock_bh(&g_cdev.lock);
 162         pd = g_cdev.active_pd;
 163         if (pd)
 164                 oz_pd_get(pd);
 165         spin_unlock_bh(&g_cdev.lock);
 166         if (pd == NULL)
 167                 return -ENXIO;
 168         if (!(pd->state & OZ_PD_S_CONNECTED))
 169                 return -EAGAIN;
 170         eb = &pd->elt_buff;
 171         ei = oz_elt_info_alloc(eb);
 172         if (ei == NULL) {
 173                 count = 0;
 174                 goto out;
 175         }
 176         elt = (struct oz_elt *)ei->data;
 177         app_hdr = (struct oz_app_hdr *)(elt+1);
 178         elt->length = sizeof(struct oz_app_hdr) + count;
 179         elt->type = OZ_ELT_APP_DATA;
 180         ei->app_id = OZ_APPID_SERIAL;
 181         ei->length = elt->length + sizeof(struct oz_elt);
 182         app_hdr->app_id = OZ_APPID_SERIAL;
 183         if (copy_from_user(app_hdr+1, buf, count))
 184                 goto out;
 185         spin_lock_bh(&pd->app_lock[OZ_APPID_USB]);
 186         ctx = (struct oz_serial_ctx *) pd->app_ctx[OZ_APPID_SERIAL];
 187         if (ctx) {
 188                 app_hdr->elt_seq_num = ctx->tx_seq_num++;
 189                 if (ctx->tx_seq_num == 0)
 190                         ctx->tx_seq_num = 1;
 191                 spin_lock(&eb->lock);
 192                 if (oz_queue_elt_info(eb, 0, 0, ei) == 0)
 193                         ei = NULL;
 194                 spin_unlock(&eb->lock);
 195         }
 196         spin_unlock_bh(&pd->app_lock[OZ_APPID_USB]);
 197 out:
 198         if (ei) {
 199                 count = 0;
 200                 spin_lock_bh(&eb->lock);
 201                 oz_elt_info_free(eb, ei);
 202                 spin_unlock_bh(&eb->lock);
 203         }
 204         oz_pd_put(pd);
 205         return count;
 206 }
 207
 208 /*
 209  * Context: process
 210  */
 211 static int oz_set_active_pd(const u8 *addr)
 212 {
 213         int rc = 0;
 214         struct oz_pd *pd;
 215         struct oz_pd *old_pd;
 216
 217         pd = oz_pd_find(addr);
 218         if (pd) {
 219                 spin_lock_bh(&g_cdev.lock);
 220                 ether_addr_copy(g_cdev.active_addr, addr);
 221                 old_pd = g_cdev.active_pd;
 222                 g_cdev.active_pd = pd;
 223                 spin_unlock_bh(&g_cdev.lock);
 224                 if (old_pd)
 225                         oz_pd_put(old_pd);
 226         } else {
 227                 if (is_zero_ether_addr(addr)) {
 228                         spin_lock_bh(&g_cdev.lock);
 229                         pd = g_cdev.active_pd;
 230                         g_cdev.active_pd = NULL;
 231                         memset(g_cdev.active_addr, 0,
 232                                 sizeof(g_cdev.active_addr));
 233                         spin_unlock_bh(&g_cdev.lock);
 234                         if (pd)
 235                                 oz_pd_put(pd);
 236                 } else {
 237                         rc = -1;
 238                 }
 239         }
 240         return rc;
 241 }
 242
 243 /*
 244  * Context: process
 245  */
 246 static long oz_cdev_ioctl(struct file *filp, unsigned int cmd,
 247                           unsigned long arg)
 248 {
 249         int rc = 0;
 250
 251         if (_IOC_TYPE(cmd) != OZ_IOCTL_MAGIC)
 252                 return -ENOTTY;
 253         if (_IOC_NR(cmd) > OZ_IOCTL_MAX)
 254                 return -ENOTTY;
 255         if (_IOC_DIR(cmd) & _IOC_READ)
 256                 rc = !access_ok(VERIFY_WRITE, (void __user *)arg,
 257                         _IOC_SIZE(cmd));
 258         else if (_IOC_DIR(cmd) & _IOC_WRITE)
 259                 rc = !access_ok(VERIFY_READ, (void __user *)arg,
 260                         _IOC_SIZE(cmd));
 261         if (rc)
 262                 return -EFAULT;
 263         switch (cmd) {
 264         case OZ_IOCTL_GET_PD_LIST: {
 265                         struct oz_pd_list list;
 266
 267                         oz_dbg(ON, "OZ_IOCTL_GET_PD_LIST\n");
 268                         memset(&list, 0, sizeof(list));
 269                         list.count = oz_get_pd_list(list.addr, OZ_MAX_PDS);
 270                         if (copy_to_user((void __user *)arg, &list,
 271                                 sizeof(list)))
 272                                 return -EFAULT;
 273                 }
 274                 break;
 275         case OZ_IOCTL_SET_ACTIVE_PD: {
 276                         u8 addr[ETH_ALEN];
 277
 278                         oz_dbg(ON, "OZ_IOCTL_SET_ACTIVE_PD\n");
 279                         if (copy_from_user(addr, (void __user *)arg, ETH_ALEN))
 280                                 return -EFAULT;
 281                         rc = oz_set_active_pd(addr);
 282                 }
 283                 break;
 284         case OZ_IOCTL_GET_ACTIVE_PD: {
 285                         u8 addr[ETH_ALEN];
 286
 287                         oz_dbg(ON, "OZ_IOCTL_GET_ACTIVE_PD\n");
 288                         spin_lock_bh(&g_cdev.lock);
 289                         ether_addr_copy(addr, g_cdev.active_addr);
 290                         spin_unlock_bh(&g_cdev.lock);
 291                         if (copy_to_user((void __user *)arg, addr, ETH_ALEN))
 292                                 return -EFAULT;
 293                 }
 294                 break;
 295         case OZ_IOCTL_ADD_BINDING:
 296         case OZ_IOCTL_REMOVE_BINDING: {
 297                         struct oz_binding_info b;
 298
 299                         if (copy_from_user(&b, (void __user *)arg,
 300                                 sizeof(struct oz_binding_info))) {
 301                                 return -EFAULT;
 302                         }
 303                         /* Make sure name is null terminated. */
 304                         b.name[OZ_MAX_BINDING_LEN-1] = 0;
 305                         if (cmd == OZ_IOCTL_ADD_BINDING)
 306                                 oz_binding_add(b.name);
 307                         else
 308                                 oz_binding_remove(b.name);
 309                 }
 310                 break;
 311         }
 312         return rc;
 313 }
 314
 315 /*
 316  * Context: process
 317  */
 318 static unsigned int oz_cdev_poll(struct file *filp, poll_table *wait)
 319 {
 320         unsigned int ret = 0;
 321         struct oz_cdev *dev = filp->private_data;
 322
 323         oz_dbg(ON, "Poll called wait = %p\n", wait);
 324         spin_lock_bh(&dev->lock);
 325         if (dev->active_pd) {
 326                 struct oz_serial_ctx *ctx = oz_cdev_claim_ctx(dev->active_pd);
 327
 328                 if (ctx) {
 329                         if (ctx->rd_in != ctx->rd_out)
 330                                 ret |= POLLIN | POLLRDNORM;
 331                         oz_cdev_release_ctx(ctx);
 332                 }
 333         }
 334         spin_unlock_bh(&dev->lock);
 335         if (wait)
 336                 poll_wait(filp, &dev->rdq, wait);
 337         return ret;
 338 }
 339
 340 /*
 341  */
 342 static const struct file_operations oz_fops = {
 343         .owner =        THIS_MODULE,
 344         .open =         oz_cdev_open,
 345         .release =      oz_cdev_release,
 346         .read =         oz_cdev_read,
 347         .write =        oz_cdev_write,
 348         .unlocked_ioctl = oz_cdev_ioctl,
 349         .poll =         oz_cdev_poll
 350 };
 351
 352 /*
 353  * Context: process
 354  */
 355 int oz_cdev_register(void)
 356 {
 357         int err;
 358         struct device *dev;
 359
 360         memset(&g_cdev, 0, sizeof(g_cdev));
 361         err = alloc_chrdev_region(&g_cdev.devnum, 0, 1, "ozwpan");
 362         if (err < 0)
 363                 return err;
 364         oz_dbg(ON, "Alloc dev number %d:%d\n",
 365                MAJOR(g_cdev.devnum), MINOR(g_cdev.devnum));
 366         cdev_init(&g_cdev.cdev, &oz_fops);
 367         g_cdev.cdev.owner = THIS_MODULE;
 368         spin_lock_init(&g_cdev.lock);
 369         init_waitqueue_head(&g_cdev.rdq);
 370         err = cdev_add(&g_cdev.cdev, g_cdev.devnum, 1);
 371         if (err < 0) {
 372                 oz_dbg(ON, "Failed to add cdev\n");
 373                 goto unregister;
 374         }
 375         g_oz_class = class_create(THIS_MODULE, "ozmo_wpan");
 376         if (IS_ERR(g_oz_class)) {
 377                 oz_dbg(ON, "Failed to register ozmo_wpan class\n");
 378                 err = PTR_ERR(g_oz_class);
 379                 goto delete;
 380         }
 381         dev = device_create(g_oz_class, NULL, g_cdev.devnum, NULL, "ozwpan");
 382         if (IS_ERR(dev)) {
 383                 oz_dbg(ON, "Failed to create sysfs entry for cdev\n");
 384                 err = PTR_ERR(dev);
 385                 goto delete;
 386         }
 387         return 0;
 388
 389 delete:
 390         cdev_del(&g_cdev.cdev);
 391 unregister:
 392         unregister_chrdev_region(g_cdev.devnum, 1);
 393         return err;
 394 }
 395
 396 /*
 397  * Context: process
 398  */
 399 int oz_cdev_deregister(void)
 400 {
 401         cdev_del(&g_cdev.cdev);
 402         unregister_chrdev_region(g_cdev.devnum, 1);
 403         if (g_oz_class) {
 404                 device_destroy(g_oz_class, g_cdev.devnum);
 405                 class_destroy(g_oz_class);
 406         }
 407         return 0;
 408 }
 409
 410 /*
 411  * Context: process
 412  */
 413 int oz_cdev_init(void)
 414 {
 415         oz_app_enable(OZ_APPID_SERIAL, 1);
 416         return 0;
 417 }
 418
 419 /*
 420  * Context: process
 421  */
 422 void oz_cdev_term(void)
 423 {
 424         oz_app_enable(OZ_APPID_SERIAL, 0);
 425 }
 426
 427 /*
 428  * Context: softirq-serialized
 429  */
 430 int oz_cdev_start(struct oz_pd *pd, int resume)
 431 {
 432         struct oz_serial_ctx *ctx;
 433         struct oz_serial_ctx *old_ctx;
 434
 435         if (resume) {
 436                 oz_dbg(ON, "Serial service resumed\n");
 437                 return 0;
 438         }
 439         ctx = kzalloc(sizeof(struct oz_serial_ctx), GFP_ATOMIC);
 440         if (ctx == NULL)
 441                 return -ENOMEM;
 442         atomic_set(&ctx->ref_count, 1);
 443         ctx->tx_seq_num = 1;
 444         spin_lock_bh(&pd->app_lock[OZ_APPID_SERIAL]);
 445         old_ctx = pd->app_ctx[OZ_APPID_SERIAL];
 446         if (old_ctx) {
 447                 spin_unlock_bh(&pd->app_lock[OZ_APPID_SERIAL]);
 448                 kfree(ctx);
 449         } else {
 450                 pd->app_ctx[OZ_APPID_SERIAL] = ctx;
 451                 spin_unlock_bh(&pd->app_lock[OZ_APPID_SERIAL]);
 452         }
 453         spin_lock(&g_cdev.lock);
 454         if ((g_cdev.active_pd == NULL) &&
 455                 ether_addr_equal(pd->mac_addr, g_cdev.active_addr)) {
 456                 oz_pd_get(pd);
 457                 g_cdev.active_pd = pd;
 458                 oz_dbg(ON, "Active PD arrived\n");
 459         }
 460         spin_unlock(&g_cdev.lock);
 461         oz_dbg(ON, "Serial service started\n");
 462         return 0;
 463 }
 464
 465 /*
 466  * Context: softirq or process
 467  */
 468 void oz_cdev_stop(struct oz_pd *pd, int pause)
 469 {
 470         struct oz_serial_ctx *ctx;
 471
 472         if (pause) {
 473                 oz_dbg(ON, "Serial service paused\n");
 474                 return;
 475         }
 476         spin_lock_bh(&pd->app_lock[OZ_APPID_SERIAL]);
 477         ctx = (struct oz_serial_ctx *) pd->app_ctx[OZ_APPID_SERIAL];
 478         pd->app_ctx[OZ_APPID_SERIAL] = NULL;
 479         spin_unlock_bh(&pd->app_lock[OZ_APPID_SERIAL]);
 480         if (ctx)
 481                 oz_cdev_release_ctx(ctx);
 482         spin_lock(&g_cdev.lock);
 483         if (pd == g_cdev.active_pd)
 484                 g_cdev.active_pd = NULL;
 485         else
 486                 pd = NULL;
 487         spin_unlock(&g_cdev.lock);
 488         if (pd) {
 489                 oz_pd_put(pd);
 490                 oz_dbg(ON, "Active PD departed\n");
 491         }
 492         oz_dbg(ON, "Serial service stopped\n");
 493 }
 494
 495 /*
 496  * Context: softirq-serialized
 497  */
 498 void oz_cdev_rx(struct oz_pd *pd, struct oz_elt *elt)
 499 {
 500         struct oz_serial_ctx *ctx;
 501         struct oz_app_hdr *app_hdr;
 502         u8 *data;
 503         int len;
 504         int space;
 505         int copy_sz;
 506         int ix;
 507
 508         ctx = oz_cdev_claim_ctx(pd);
 509         if (ctx == NULL) {
 510                 oz_dbg(ON, "Cannot claim serial context\n");
 511                 return;
 512         }
 513
 514         app_hdr = (struct oz_app_hdr *)(elt+1);
 515         /* If sequence number is non-zero then check it is not a duplicate.
 516          */
 517         if (app_hdr->elt_seq_num != 0) {
 518                 if (((ctx->rx_seq_num - app_hdr->elt_seq_num) & 0x80) == 0) {
 519                         /* Reject duplicate element. */
 520                         oz_dbg(ON, "Duplicate element:%02x %02x\n",
 521                                app_hdr->elt_seq_num, ctx->rx_seq_num);
 522                         goto out;
 523                 }
 524         }
 525         ctx->rx_seq_num = app_hdr->elt_seq_num;
 526         len = elt->length - sizeof(struct oz_app_hdr);
 527         data = ((u8 *)(elt+1)) + sizeof(struct oz_app_hdr);
 528         if (len <= 0)
 529                 goto out;
 530         space = ctx->rd_out - ctx->rd_in - 1;
 531         if (space < 0)
 532                 space += OZ_RD_BUF_SZ;
 533         if (len > space) {
 534                 oz_dbg(ON, "Not enough space:%d %d\n", len, space);
 535                 len = space;
 536         }
 537         ix = ctx->rd_in;
 538         copy_sz = OZ_RD_BUF_SZ - ix;
 539         if (copy_sz > len)
 540                 copy_sz = len;
 541         memcpy(&ctx->rd_buf[ix], data, copy_sz);
 542         len -= copy_sz;
 543         ix += copy_sz;
 544         if (ix == OZ_RD_BUF_SZ)
 545                 ix = 0;
 546         if (len) {
 547                 memcpy(ctx->rd_buf, data+copy_sz, len);
 548                 ix = len;
 549         }
 550         ctx->rd_in = ix;
 551         wake_up(&g_cdev.rdq);
 552 out:
 553         oz_cdev_release_ctx(ctx);
 554 }