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 -ENXIO;
 165         if (!(pd->state & OZ_PD_S_CONNECTED))
 166                 return -EAGAIN;
 167         eb = &pd->elt_buff;
 168         ei = oz_elt_info_alloc(eb);
 169         if (ei == NULL) {
 170                 count = 0;
 171                 goto out;
 172         }
 173         elt = (struct oz_elt *)ei->data;
 174         app_hdr = (struct oz_app_hdr *)(elt+1);
 175         elt->length = sizeof(struct oz_app_hdr) + count;
 176         elt->type = OZ_ELT_APP_DATA;
 177         ei->app_id = OZ_APPID_SERIAL;
 178         ei->length = elt->length + sizeof(struct oz_elt);
 179         app_hdr->app_id = OZ_APPID_SERIAL;
 180         if (copy_from_user(app_hdr+1, buf, count))
 181                 goto out;
 182         spin_lock_bh(&pd->app_lock[OZ_APPID_USB-1]);
 183         ctx = (struct oz_serial_ctx *)pd->app_ctx[OZ_APPID_SERIAL-1];
 184         if (ctx) {
 185                 app_hdr->elt_seq_num = ctx->tx_seq_num++;
 186                 if (ctx->tx_seq_num == 0)
 187                         ctx->tx_seq_num = 1;
 188                 spin_lock(&eb->lock);
 189                 if (oz_queue_elt_info(eb, 0, 0, ei) == 0)
 190                         ei = NULL;
 191                 spin_unlock(&eb->lock);
 192         }
 193         spin_unlock_bh(&pd->app_lock[OZ_APPID_USB-1]);
 194 out:
 195         if (ei) {
 196                 count = 0;
 197                 spin_lock_bh(&eb->lock);
 198                 oz_elt_info_free(eb, ei);
 199                 spin_unlock_bh(&eb->lock);
 200         }
 201         oz_pd_put(pd);
 202         return count;
 203 }
 204
 205 /*
 206  * Context: process
 207  */
 208 static int oz_set_active_pd(const u8 *addr)
 209 {
 210         int rc = 0;
 211         struct oz_pd *pd;
 212         struct oz_pd *old_pd;
 213
 214         pd = oz_pd_find(addr);
 215         if (pd) {
 216                 spin_lock_bh(&g_cdev.lock);
 217                 memcpy(g_cdev.active_addr, addr, ETH_ALEN);
 218                 old_pd = g_cdev.active_pd;
 219                 g_cdev.active_pd = pd;
 220                 spin_unlock_bh(&g_cdev.lock);
 221                 if (old_pd)
 222                         oz_pd_put(old_pd);
 223         } else {
 224                 if (is_zero_ether_addr(addr)) {
 225                         spin_lock_bh(&g_cdev.lock);
 226                         pd = g_cdev.active_pd;
 227                         g_cdev.active_pd = NULL;
 228                         memset(g_cdev.active_addr, 0,
 229                                 sizeof(g_cdev.active_addr));
 230                         spin_unlock_bh(&g_cdev.lock);
 231                         if (pd)
 232                                 oz_pd_put(pd);
 233                 } else {
 234                         rc = -1;
 235                 }
 236         }
 237         return rc;
 238 }
 239
 240 /*
 241  * Context: process
 242  */
 243 static long oz_cdev_ioctl(struct file *filp, unsigned int cmd,
 244                           unsigned long arg)
 245 {
 246         int rc = 0;
 247
 248         if (_IOC_TYPE(cmd) != OZ_IOCTL_MAGIC)
 249                 return -ENOTTY;
 250         if (_IOC_NR(cmd) > OZ_IOCTL_MAX)
 251                 return -ENOTTY;
 252         if (_IOC_DIR(cmd) & _IOC_READ)
 253                 rc = !access_ok(VERIFY_WRITE, (void __user *)arg,
 254                         _IOC_SIZE(cmd));
 255         else if (_IOC_DIR(cmd) & _IOC_WRITE)
 256                 rc = !access_ok(VERIFY_READ, (void __user *)arg,
 257                         _IOC_SIZE(cmd));
 258         if (rc)
 259                 return -EFAULT;
 260         switch (cmd) {
 261         case OZ_IOCTL_GET_PD_LIST: {
 262                         struct oz_pd_list list;
 263                         oz_dbg(ON, "OZ_IOCTL_GET_PD_LIST\n");
 264                         memset(&list, 0, sizeof(list));
 265                         list.count = oz_get_pd_list(list.addr, OZ_MAX_PDS);
 266                         if (copy_to_user((void __user *)arg, &list,
 267                                 sizeof(list)))
 268                                 return -EFAULT;
 269                 }
 270                 break;
 271         case OZ_IOCTL_SET_ACTIVE_PD: {
 272                         u8 addr[ETH_ALEN];
 273                         oz_dbg(ON, "OZ_IOCTL_SET_ACTIVE_PD\n");
 274                         if (copy_from_user(addr, (void __user *)arg, ETH_ALEN))
 275                                 return -EFAULT;
 276                         rc = oz_set_active_pd(addr);
 277                 }
 278                 break;
 279         case OZ_IOCTL_GET_ACTIVE_PD: {
 280                         u8 addr[ETH_ALEN];
 281                         oz_dbg(ON, "OZ_IOCTL_GET_ACTIVE_PD\n");
 282                         spin_lock_bh(&g_cdev.lock);
 283                         memcpy(addr, g_cdev.active_addr, ETH_ALEN);
 284                         spin_unlock_bh(&g_cdev.lock);
 285                         if (copy_to_user((void __user *)arg, addr, ETH_ALEN))
 286                                 return -EFAULT;
 287                 }
 288                 break;
 289         case OZ_IOCTL_ADD_BINDING:
 290         case OZ_IOCTL_REMOVE_BINDING: {
 291                         struct oz_binding_info b;
 292                         if (copy_from_user(&b, (void __user *)arg,
 293                                 sizeof(struct oz_binding_info))) {
 294                                 return -EFAULT;
 295                         }
 296                         /* Make sure name is null terminated. */
 297                         b.name[OZ_MAX_BINDING_LEN-1] = 0;
 298                         if (cmd == OZ_IOCTL_ADD_BINDING)
 299                                 oz_binding_add(b.name);
 300                         else
 301                                 oz_binding_remove(b.name);
 302                 }
 303                 break;
 304         }
 305         return rc;
 306 }
 307
 308 /*
 309  * Context: process
 310  */
 311 static unsigned int oz_cdev_poll(struct file *filp, poll_table *wait)
 312 {
 313         unsigned int ret = 0;
 314         struct oz_cdev *dev = filp->private_data;
 315
 316         oz_dbg(ON, "Poll called wait = %p\n", wait);
 317         spin_lock_bh(&dev->lock);
 318         if (dev->active_pd) {
 319                 struct oz_serial_ctx *ctx = oz_cdev_claim_ctx(dev->active_pd);
 320                 if (ctx) {
 321                         if (ctx->rd_in != ctx->rd_out)
 322                                 ret |= POLLIN | POLLRDNORM;
 323                         oz_cdev_release_ctx(ctx);
 324                 }
 325         }
 326         spin_unlock_bh(&dev->lock);
 327         if (wait)
 328                 poll_wait(filp, &dev->rdq, wait);
 329         return ret;
 330 }
 331
 332 /*
 333  */
 334 static const struct file_operations oz_fops = {
 335         .owner =        THIS_MODULE,
 336         .open =         oz_cdev_open,
 337         .release =      oz_cdev_release,
 338         .read =         oz_cdev_read,
 339         .write =        oz_cdev_write,
 340         .unlocked_ioctl = oz_cdev_ioctl,
 341         .poll =         oz_cdev_poll
 342 };
 343
 344 /*
 345  * Context: process
 346  */
 347 int oz_cdev_register(void)
 348 {
 349         int err;
 350         struct device *dev;
 351
 352         memset(&g_cdev, 0, sizeof(g_cdev));
 353         err = alloc_chrdev_region(&g_cdev.devnum, 0, 1, "ozwpan");
 354         if (err < 0)
 355                 return err;
 356         oz_dbg(ON, "Alloc dev number %d:%d\n",
 357                MAJOR(g_cdev.devnum), MINOR(g_cdev.devnum));
 358         cdev_init(&g_cdev.cdev, &oz_fops);
 359         g_cdev.cdev.owner = THIS_MODULE;
 360         g_cdev.cdev.ops = &oz_fops;
 361         spin_lock_init(&g_cdev.lock);
 362         init_waitqueue_head(&g_cdev.rdq);
 363         err = cdev_add(&g_cdev.cdev, g_cdev.devnum, 1);
 364         if (err < 0) {
 365                 oz_dbg(ON, "Failed to add cdev\n");
 366                 goto unregister;
 367         }
 368         g_oz_class = class_create(THIS_MODULE, "ozmo_wpan");
 369         if (IS_ERR(g_oz_class)) {
 370                 oz_dbg(ON, "Failed to register ozmo_wpan class\n");
 371                 err = PTR_ERR(g_oz_class);
 372                 goto delete;
 373         }
 374         dev = device_create(g_oz_class, NULL, g_cdev.devnum, NULL, "ozwpan");
 375         if (IS_ERR(dev)) {
 376                 oz_dbg(ON, "Failed to create sysfs entry for cdev\n");
 377                 err = PTR_ERR(dev);
 378                 goto delete;
 379         }
 380         return 0;
 381
 382 delete:
 383         cdev_del(&g_cdev.cdev);
 384 unregister:
 385         unregister_chrdev_region(g_cdev.devnum, 1);
 386         return err;
 387 }
 388
 389 /*
 390  * Context: process
 391  */
 392 int oz_cdev_deregister(void)
 393 {
 394         cdev_del(&g_cdev.cdev);
 395         unregister_chrdev_region(g_cdev.devnum, 1);
 396         if (g_oz_class) {
 397                 device_destroy(g_oz_class, g_cdev.devnum);
 398                 class_destroy(g_oz_class);
 399         }
 400         return 0;
 401 }
 402
 403 /*
 404  * Context: process
 405  */
 406 int oz_cdev_init(void)
 407 {
 408         oz_app_enable(OZ_APPID_SERIAL, 1);
 409         return 0;
 410 }
 411
 412 /*
 413  * Context: process
 414  */
 415 void oz_cdev_term(void)
 416 {
 417         oz_app_enable(OZ_APPID_SERIAL, 0);
 418 }
 419
 420 /*
 421  * Context: softirq-serialized
 422  */
 423 int oz_cdev_start(struct oz_pd *pd, int resume)
 424 {
 425         struct oz_serial_ctx *ctx;
 426         struct oz_serial_ctx *old_ctx;
 427
 428         if (resume) {
 429                 oz_dbg(ON, "Serial service resumed\n");
 430                 return 0;
 431         }
 432         ctx = kzalloc(sizeof(struct oz_serial_ctx), GFP_ATOMIC);
 433         if (ctx == NULL)
 434                 return -ENOMEM;
 435         atomic_set(&ctx->ref_count, 1);
 436         ctx->tx_seq_num = 1;
 437         spin_lock_bh(&pd->app_lock[OZ_APPID_SERIAL-1]);
 438         old_ctx = pd->app_ctx[OZ_APPID_SERIAL-1];
 439         if (old_ctx) {
 440                 spin_unlock_bh(&pd->app_lock[OZ_APPID_SERIAL-1]);
 441                 kfree(ctx);
 442         } else {
 443                 pd->app_ctx[OZ_APPID_SERIAL-1] = ctx;
 444                 spin_unlock_bh(&pd->app_lock[OZ_APPID_SERIAL-1]);
 445         }
 446         spin_lock(&g_cdev.lock);
 447         if ((g_cdev.active_pd == NULL) &&
 448                 (memcmp(pd->mac_addr, g_cdev.active_addr, ETH_ALEN) == 0)) {
 449                 oz_pd_get(pd);
 450                 g_cdev.active_pd = pd;
 451                 oz_dbg(ON, "Active PD arrived\n");
 452         }
 453         spin_unlock(&g_cdev.lock);
 454         oz_dbg(ON, "Serial service started\n");
 455         return 0;
 456 }
 457
 458 /*
 459  * Context: softirq or process
 460  */
 461 void oz_cdev_stop(struct oz_pd *pd, int pause)
 462 {
 463         struct oz_serial_ctx *ctx;
 464
 465         if (pause) {
 466                 oz_dbg(ON, "Serial service paused\n");
 467                 return;
 468         }
 469         spin_lock_bh(&pd->app_lock[OZ_APPID_SERIAL-1]);
 470         ctx = (struct oz_serial_ctx *)pd->app_ctx[OZ_APPID_SERIAL-1];
 471         pd->app_ctx[OZ_APPID_SERIAL-1] = NULL;
 472         spin_unlock_bh(&pd->app_lock[OZ_APPID_SERIAL-1]);
 473         if (ctx)
 474                 oz_cdev_release_ctx(ctx);
 475         spin_lock(&g_cdev.lock);
 476         if (pd == g_cdev.active_pd)
 477                 g_cdev.active_pd = NULL;
 478         else
 479                 pd = NULL;
 480         spin_unlock(&g_cdev.lock);
 481         if (pd) {
 482                 oz_pd_put(pd);
 483                 oz_dbg(ON, "Active PD departed\n");
 484         }
 485         oz_dbg(ON, "Serial service stopped\n");
 486 }
 487
 488 /*
 489  * Context: softirq-serialized
 490  */
 491 void oz_cdev_rx(struct oz_pd *pd, struct oz_elt *elt)
 492 {
 493         struct oz_serial_ctx *ctx;
 494         struct oz_app_hdr *app_hdr;
 495         u8 *data;
 496         int len;
 497         int space;
 498         int copy_sz;
 499         int ix;
 500
 501         ctx = oz_cdev_claim_ctx(pd);
 502         if (ctx == NULL) {
 503                 oz_dbg(ON, "Cannot claim serial context\n");
 504                 return;
 505         }
 506
 507         app_hdr = (struct oz_app_hdr *)(elt+1);
 508         /* If sequence number is non-zero then check it is not a duplicate.
 509          */
 510         if (app_hdr->elt_seq_num != 0) {
 511                 if (((ctx->rx_seq_num - app_hdr->elt_seq_num) & 0x80) == 0) {
 512                         /* Reject duplicate element. */
 513                         oz_dbg(ON, "Duplicate element:%02x %02x\n",
 514                                app_hdr->elt_seq_num, ctx->rx_seq_num);
 515                         goto out;
 516                 }
 517         }
 518         ctx->rx_seq_num = app_hdr->elt_seq_num;
 519         len = elt->length - sizeof(struct oz_app_hdr);
 520         data = ((u8 *)(elt+1)) + sizeof(struct oz_app_hdr);
 521         if (len <= 0)
 522                 goto out;
 523         space = ctx->rd_out - ctx->rd_in - 1;
 524         if (space < 0)
 525                 space += OZ_RD_BUF_SZ;
 526         if (len > space) {
 527                 oz_dbg(ON, "Not enough space:%d %d\n", len, space);
 528                 len = space;
 529         }
 530         ix = ctx->rd_in;
 531         copy_sz = OZ_RD_BUF_SZ - ix;
 532         if (copy_sz > len)
 533                 copy_sz = len;
 534         memcpy(&ctx->rd_buf[ix], data, copy_sz);
 535         len -= copy_sz;
 536         ix += copy_sz;
 537         if (ix == OZ_RD_BUF_SZ)
 538                 ix = 0;
 539         if (len) {
 540                 memcpy(ctx->rd_buf, data+copy_sz, len);
 541                 ix = len;
 542         }
 543         ctx->rd_in = ix;
 544         wake_up(&g_cdev.rdq);
 545 out:
 546         oz_cdev_release_ctx(ctx);
 547 }