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-1]);
  53         ctx = (struct oz_serial_ctx *)pd->app_ctx[OZ_APPID_SERIAL-1];
  54         if (ctx)
  55                 atomic_inc(&ctx->ref_count);
  56         spin_unlock_bh(&pd->app_lock[OZ_APPID_SERIAL-1]);
  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         spin_lock_bh(&g_cdev.lock);
 159         pd = g_cdev.active_pd;
 160         if (pd)
 161                 oz_pd_get(pd);
 162         spin_unlock_bh(&g_cdev.lock);
 163         if (pd == NULL)
 164                 return -1;
 165         eb = &pd->elt_buff;
 166         ei = oz_elt_info_alloc(eb);
 167         if (ei == NULL) {
 168                 count = 0;
 169                 goto out;
 170         }
 171         elt = (struct oz_elt *)ei->data;
 172         app_hdr = (struct oz_app_hdr *)(elt+1);
 173         elt->length = sizeof(struct oz_app_hdr) + count;
 174         elt->type = OZ_ELT_APP_DATA;
 175         ei->app_id = OZ_APPID_SERIAL;
 176         ei->length = elt->length + sizeof(struct oz_elt);
 177         app_hdr->app_id = OZ_APPID_SERIAL;
 178         if (copy_from_user(app_hdr+1, buf, count))
 179                 goto out;
 180         spin_lock_bh(&pd->app_lock[OZ_APPID_USB-1]);
 181         ctx = (struct oz_serial_ctx *)pd->app_ctx[OZ_APPID_SERIAL-1];
 182         if (ctx) {
 183                 app_hdr->elt_seq_num = ctx->tx_seq_num++;
 184                 if (ctx->tx_seq_num == 0)
 185                         ctx->tx_seq_num = 1;
 186                 spin_lock(&eb->lock);
 187                 if (oz_queue_elt_info(eb, 0, 0, ei) == 0)
 188                         ei = NULL;
 189                 spin_unlock(&eb->lock);
 190         }
 191         spin_unlock_bh(&pd->app_lock[OZ_APPID_USB-1]);
 192 out:
 193         if (ei) {
 194                 count = 0;
 195                 spin_lock_bh(&eb->lock);
 196                 oz_elt_info_free(eb, ei);
 197                 spin_unlock_bh(&eb->lock);
 198         }
 199         oz_pd_put(pd);
 200         return count;
 201 }
 202
 203 /*
 204  * Context: process
 205  */
 206 static int oz_set_active_pd(const u8 *addr)
 207 {
 208         int rc = 0;
 209         struct oz_pd *pd;
 210         struct oz_pd *old_pd;
 211
 212         pd = oz_pd_find(addr);
 213         if (pd) {
 214                 spin_lock_bh(&g_cdev.lock);
 215                 memcpy(g_cdev.active_addr, addr, ETH_ALEN);
 216                 old_pd = g_cdev.active_pd;
 217                 g_cdev.active_pd = pd;
 218                 spin_unlock_bh(&g_cdev.lock);
 219                 if (old_pd)
 220                         oz_pd_put(old_pd);
 221         } else {
 222                 if (is_zero_ether_addr(addr)) {
 223                         spin_lock_bh(&g_cdev.lock);
 224                         pd = g_cdev.active_pd;
 225                         g_cdev.active_pd = NULL;
 226                         memset(g_cdev.active_addr, 0,
 227                                 sizeof(g_cdev.active_addr));
 228                         spin_unlock_bh(&g_cdev.lock);
 229                         if (pd)
 230                                 oz_pd_put(pd);
 231                 } else {
 232                         rc = -1;
 233                 }
 234         }
 235         return rc;
 236 }
 237
 238 /*
 239  * Context: process
 240  */
 241 static long oz_cdev_ioctl(struct file *filp, unsigned int cmd,
 242                           unsigned long arg)
 243 {
 244         int rc = 0;
 245
 246         if (_IOC_TYPE(cmd) != OZ_IOCTL_MAGIC)
 247                 return -ENOTTY;
 248         if (_IOC_NR(cmd) > OZ_IOCTL_MAX)
 249                 return -ENOTTY;
 250         if (_IOC_DIR(cmd) & _IOC_READ)
 251                 rc = !access_ok(VERIFY_WRITE, (void __user *)arg,
 252                         _IOC_SIZE(cmd));
 253         else if (_IOC_DIR(cmd) & _IOC_WRITE)
 254                 rc = !access_ok(VERIFY_READ, (void __user *)arg,
 255                         _IOC_SIZE(cmd));
 256         if (rc)
 257                 return -EFAULT;
 258         switch (cmd) {
 259         case OZ_IOCTL_GET_PD_LIST: {
 260                         struct oz_pd_list list;
 261                         oz_dbg(ON, "OZ_IOCTL_GET_PD_LIST\n");
 262                         memset(&list, 0, sizeof(list));
 263                         list.count = oz_get_pd_list(list.addr, OZ_MAX_PDS);
 264                         if (copy_to_user((void __user *)arg, &list,
 265                                 sizeof(list)))
 266                                 return -EFAULT;
 267                 }
 268                 break;
 269         case OZ_IOCTL_SET_ACTIVE_PD: {
 270                         u8 addr[ETH_ALEN];
 271                         oz_dbg(ON, "OZ_IOCTL_SET_ACTIVE_PD\n");
 272                         if (copy_from_user(addr, (void __user *)arg, ETH_ALEN))
 273                                 return -EFAULT;
 274                         rc = oz_set_active_pd(addr);
 275                 }
 276                 break;
 277         case OZ_IOCTL_GET_ACTIVE_PD: {
 278                         u8 addr[ETH_ALEN];
 279                         oz_dbg(ON, "OZ_IOCTL_GET_ACTIVE_PD\n");
 280                         spin_lock_bh(&g_cdev.lock);
 281                         memcpy(addr, g_cdev.active_addr, ETH_ALEN);
 282                         spin_unlock_bh(&g_cdev.lock);
 283                         if (copy_to_user((void __user *)arg, addr, ETH_ALEN))
 284                                 return -EFAULT;
 285                 }
 286                 break;
 287         case OZ_IOCTL_ADD_BINDING:
 288         case OZ_IOCTL_REMOVE_BINDING: {
 289                         struct oz_binding_info b;
 290                         if (copy_from_user(&b, (void __user *)arg,
 291                                 sizeof(struct oz_binding_info))) {
 292                                 return -EFAULT;
 293                         }
 294                         /* Make sure name is null terminated. */
 295                         b.name[OZ_MAX_BINDING_LEN-1] = 0;
 296                         if (cmd == OZ_IOCTL_ADD_BINDING)
 297                                 oz_binding_add(b.name);
 298                         else
 299                                 oz_binding_remove(b.name);
 300                 }
 301                 break;
 302         }
 303         return rc;
 304 }
 305
 306 /*
 307  * Context: process
 308  */
 309 static unsigned int oz_cdev_poll(struct file *filp, poll_table *wait)
 310 {
 311         unsigned int ret = 0;
 312         struct oz_cdev *dev = filp->private_data;
 313
 314         oz_dbg(ON, "Poll called wait = %p\n", wait);
 315         spin_lock_bh(&dev->lock);
 316         if (dev->active_pd) {
 317                 struct oz_serial_ctx *ctx = oz_cdev_claim_ctx(dev->active_pd);
 318                 if (ctx) {
 319                         if (ctx->rd_in != ctx->rd_out)
 320                                 ret |= POLLIN | POLLRDNORM;
 321                         oz_cdev_release_ctx(ctx);
 322                 }
 323         }
 324         spin_unlock_bh(&dev->lock);
 325         if (wait)
 326                 poll_wait(filp, &dev->rdq, wait);
 327         return ret;
 328 }
 329
 330 /*
 331  */
 332 static const struct file_operations oz_fops = {
 333         .owner =        THIS_MODULE,
 334         .open =         oz_cdev_open,
 335         .release =      oz_cdev_release,
 336         .read =         oz_cdev_read,
 337         .write =        oz_cdev_write,
 338         .unlocked_ioctl = oz_cdev_ioctl,
 339         .poll =         oz_cdev_poll
 340 };
 341
 342 /*
 343  * Context: process
 344  */
 345 int oz_cdev_register(void)
 346 {
 347         int err;
 348         struct device *dev;
 349
 350         memset(&g_cdev, 0, sizeof(g_cdev));
 351         err = alloc_chrdev_region(&g_cdev.devnum, 0, 1, "ozwpan");
 352         if (err < 0)
 353                 return err;
 354         oz_dbg(ON, "Alloc dev number %d:%d\n",
 355                MAJOR(g_cdev.devnum), MINOR(g_cdev.devnum));
 356         cdev_init(&g_cdev.cdev, &oz_fops);
 357         g_cdev.cdev.owner = THIS_MODULE;
 358         g_cdev.cdev.ops = &oz_fops;
 359         spin_lock_init(&g_cdev.lock);
 360         init_waitqueue_head(&g_cdev.rdq);
 361         err = cdev_add(&g_cdev.cdev, g_cdev.devnum, 1);
 362         if (err < 0) {
 363                 oz_dbg(ON, "Failed to add cdev\n");
 364                 goto unregister;
 365         }
 366         g_oz_class = class_create(THIS_MODULE, "ozmo_wpan");
 367         if (IS_ERR(g_oz_class)) {
 368                 oz_dbg(ON, "Failed to register ozmo_wpan class\n");
 369                 err = PTR_ERR(g_oz_class);
 370                 goto delete;
 371         }
 372         dev = device_create(g_oz_class, NULL, g_cdev.devnum, NULL, "ozwpan");
 373         if (IS_ERR(dev)) {
 374                 oz_dbg(ON, "Failed to create sysfs entry for cdev\n");
 375                 err = PTR_ERR(dev);
 376                 goto delete;
 377         }
 378         return 0;
 379
 380 delete:
 381         cdev_del(&g_cdev.cdev);
 382 unregister:
 383         unregister_chrdev_region(g_cdev.devnum, 1);
 384         return err;
 385 }
 386
 387 /*
 388  * Context: process
 389  */
 390 int oz_cdev_deregister(void)
 391 {
 392         cdev_del(&g_cdev.cdev);
 393         unregister_chrdev_region(g_cdev.devnum, 1);
 394         if (g_oz_class) {
 395                 device_destroy(g_oz_class, g_cdev.devnum);
 396                 class_destroy(g_oz_class);
 397         }
 398         return 0;
 399 }
 400
 401 /*
 402  * Context: process
 403  */
 404 int oz_cdev_init(void)
 405 {
 406         oz_app_enable(OZ_APPID_SERIAL, 1);
 407         return 0;
 408 }
 409
 410 /*
 411  * Context: process
 412  */
 413 void oz_cdev_term(void)
 414 {
 415         oz_app_enable(OZ_APPID_SERIAL, 0);
 416 }
 417
 418 /*
 419  * Context: softirq-serialized
 420  */
 421 int oz_cdev_start(struct oz_pd *pd, int resume)
 422 {
 423         struct oz_serial_ctx *ctx;
 424         struct oz_serial_ctx *old_ctx;
 425
 426         if (resume) {
 427                 oz_dbg(ON, "Serial service resumed\n");
 428                 return 0;
 429         }
 430         ctx = kzalloc(sizeof(struct oz_serial_ctx), GFP_ATOMIC);
 431         if (ctx == NULL)
 432                 return -ENOMEM;
 433         atomic_set(&ctx->ref_count, 1);
 434         ctx->tx_seq_num = 1;
 435         spin_lock_bh(&pd->app_lock[OZ_APPID_SERIAL-1]);
 436         old_ctx = pd->app_ctx[OZ_APPID_SERIAL-1];
 437         if (old_ctx) {
 438                 spin_unlock_bh(&pd->app_lock[OZ_APPID_SERIAL-1]);
 439                 kfree(ctx);
 440         } else {
 441                 pd->app_ctx[OZ_APPID_SERIAL-1] = ctx;
 442                 spin_unlock_bh(&pd->app_lock[OZ_APPID_SERIAL-1]);
 443         }
 444         spin_lock(&g_cdev.lock);
 445         if ((g_cdev.active_pd == NULL) &&
 446                 (memcmp(pd->mac_addr, g_cdev.active_addr, ETH_ALEN) == 0)) {
 447                 oz_pd_get(pd);
 448                 g_cdev.active_pd = pd;
 449                 oz_dbg(ON, "Active PD arrived\n");
 450         }
 451         spin_unlock(&g_cdev.lock);
 452         oz_dbg(ON, "Serial service started\n");
 453         return 0;
 454 }
 455
 456 /*
 457  * Context: softirq or process
 458  */
 459 void oz_cdev_stop(struct oz_pd *pd, int pause)
 460 {
 461         struct oz_serial_ctx *ctx;
 462
 463         if (pause) {
 464                 oz_dbg(ON, "Serial service paused\n");
 465                 return;
 466         }
 467         spin_lock_bh(&pd->app_lock[OZ_APPID_SERIAL-1]);
 468         ctx = (struct oz_serial_ctx *)pd->app_ctx[OZ_APPID_SERIAL-1];
 469         pd->app_ctx[OZ_APPID_SERIAL-1] = NULL;
 470         spin_unlock_bh(&pd->app_lock[OZ_APPID_SERIAL-1]);
 471         if (ctx)
 472                 oz_cdev_release_ctx(ctx);
 473         spin_lock(&g_cdev.lock);
 474         if (pd == g_cdev.active_pd)
 475                 g_cdev.active_pd = NULL;
 476         else
 477                 pd = NULL;
 478         spin_unlock(&g_cdev.lock);
 479         if (pd) {
 480                 oz_pd_put(pd);
 481                 oz_dbg(ON, "Active PD departed\n");
 482         }
 483         oz_dbg(ON, "Serial service stopped\n");
 484 }
 485
 486 /*
 487  * Context: softirq-serialized
 488  */
 489 void oz_cdev_rx(struct oz_pd *pd, struct oz_elt *elt)
 490 {
 491         struct oz_serial_ctx *ctx;
 492         struct oz_app_hdr *app_hdr;
 493         u8 *data;
 494         int len;
 495         int space;
 496         int copy_sz;
 497         int ix;
 498
 499         ctx = oz_cdev_claim_ctx(pd);
 500         if (ctx == NULL) {
 501                 oz_dbg(ON, "Cannot claim serial context\n");
 502                 return;
 503         }
 504
 505         app_hdr = (struct oz_app_hdr *)(elt+1);
 506         /* If sequence number is non-zero then check it is not a duplicate.
 507          */
 508         if (app_hdr->elt_seq_num != 0) {
 509                 if (((ctx->rx_seq_num - app_hdr->elt_seq_num) & 0x80) == 0) {
 510                         /* Reject duplicate element. */
 511                         oz_dbg(ON, "Duplicate element:%02x %02x\n",
 512                                app_hdr->elt_seq_num, ctx->rx_seq_num);
 513                         goto out;
 514                 }
 515         }
 516         ctx->rx_seq_num = app_hdr->elt_seq_num;
 517         len = elt->length - sizeof(struct oz_app_hdr);
 518         data = ((u8 *)(elt+1)) + sizeof(struct oz_app_hdr);
 519         if (len <= 0)
 520                 goto out;
 521         space = ctx->rd_out - ctx->rd_in - 1;
 522         if (space < 0)
 523                 space += OZ_RD_BUF_SZ;
 524         if (len > space) {
 525                 oz_dbg(ON, "Not enough space:%d %d\n", len, space);
 526                 len = space;
 527         }
 528         ix = ctx->rd_in;
 529         copy_sz = OZ_RD_BUF_SZ - ix;
 530         if (copy_sz > len)
 531                 copy_sz = len;
 532         memcpy(&ctx->rd_buf[ix], data, copy_sz);
 533         len -= copy_sz;
 534         ix += copy_sz;
 535         if (ix == OZ_RD_BUF_SZ)
 536                 ix = 0;
 537         if (len) {
 538                 memcpy(ctx->rd_buf, data+copy_sz, len);
 539                 ix = len;
 540         }
 541         ctx->rd_in = ix;
 542         wake_up(&g_cdev.rdq);
 543 out:
 544         oz_cdev_release_ctx(ctx);
 545 }