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         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-1]);
 186         ctx = (struct oz_serial_ctx *)pd->app_ctx[OZ_APPID_SERIAL-1];
 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-1]);
 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                         oz_dbg(ON, "OZ_IOCTL_GET_PD_LIST\n");
 267                         memset(&list, 0, sizeof(list));
 268                         list.count = oz_get_pd_list(list.addr, OZ_MAX_PDS);
 269                         if (copy_to_user((void __user *)arg, &list,
 270                                 sizeof(list)))
 271                                 return -EFAULT;
 272                 }
 273                 break;
 274         case OZ_IOCTL_SET_ACTIVE_PD: {
 275                         u8 addr[ETH_ALEN];
 276                         oz_dbg(ON, "OZ_IOCTL_SET_ACTIVE_PD\n");
 277                         if (copy_from_user(addr, (void __user *)arg, ETH_ALEN))
 278                                 return -EFAULT;
 279                         rc = oz_set_active_pd(addr);
 280                 }
 281                 break;
 282         case OZ_IOCTL_GET_ACTIVE_PD: {
 283                         u8 addr[ETH_ALEN];
 284                         oz_dbg(ON, "OZ_IOCTL_GET_ACTIVE_PD\n");
 285                         spin_lock_bh(&g_cdev.lock);
 286                         ether_addr_copy(addr, g_cdev.active_addr);
 287                         spin_unlock_bh(&g_cdev.lock);
 288                         if (copy_to_user((void __user *)arg, addr, ETH_ALEN))
 289                                 return -EFAULT;
 290                 }
 291                 break;
 292         case OZ_IOCTL_ADD_BINDING:
 293         case OZ_IOCTL_REMOVE_BINDING: {
 294                         struct oz_binding_info b;
 295                         if (copy_from_user(&b, (void __user *)arg,
 296                                 sizeof(struct oz_binding_info))) {
 297                                 return -EFAULT;
 298                         }
 299                         /* Make sure name is null terminated. */
 300                         b.name[OZ_MAX_BINDING_LEN-1] = 0;
 301                         if (cmd == OZ_IOCTL_ADD_BINDING)
 302                                 oz_binding_add(b.name);
 303                         else
 304                                 oz_binding_remove(b.name);
 305                 }
 306                 break;
 307         }
 308         return rc;
 309 }
 310
 311 /*
 312  * Context: process
 313  */
 314 static unsigned int oz_cdev_poll(struct file *filp, poll_table *wait)
 315 {
 316         unsigned int ret = 0;
 317         struct oz_cdev *dev = filp->private_data;
 318
 319         oz_dbg(ON, "Poll called wait = %p\n", wait);
 320         spin_lock_bh(&dev->lock);
 321         if (dev->active_pd) {
 322                 struct oz_serial_ctx *ctx = oz_cdev_claim_ctx(dev->active_pd);
 323                 if (ctx) {
 324                         if (ctx->rd_in != ctx->rd_out)
 325                                 ret |= POLLIN | POLLRDNORM;
 326                         oz_cdev_release_ctx(ctx);
 327                 }
 328         }
 329         spin_unlock_bh(&dev->lock);
 330         if (wait)
 331                 poll_wait(filp, &dev->rdq, wait);
 332         return ret;
 333 }
 334
 335 /*
 336  */
 337 static const struct file_operations oz_fops = {
 338         .owner =        THIS_MODULE,
 339         .open =         oz_cdev_open,
 340         .release =      oz_cdev_release,
 341         .read =         oz_cdev_read,
 342         .write =        oz_cdev_write,
 343         .unlocked_ioctl = oz_cdev_ioctl,
 344         .poll =         oz_cdev_poll
 345 };
 346
 347 /*
 348  * Context: process
 349  */
 350 int oz_cdev_register(void)
 351 {
 352         int err;
 353         struct device *dev;
 354
 355         memset(&g_cdev, 0, sizeof(g_cdev));
 356         err = alloc_chrdev_region(&g_cdev.devnum, 0, 1, "ozwpan");
 357         if (err < 0)
 358                 return err;
 359         oz_dbg(ON, "Alloc dev number %d:%d\n",
 360                MAJOR(g_cdev.devnum), MINOR(g_cdev.devnum));
 361         cdev_init(&g_cdev.cdev, &oz_fops);
 362         g_cdev.cdev.owner = THIS_MODULE;
 363         g_cdev.cdev.ops = &oz_fops;
 364         spin_lock_init(&g_cdev.lock);
 365         init_waitqueue_head(&g_cdev.rdq);
 366         err = cdev_add(&g_cdev.cdev, g_cdev.devnum, 1);
 367         if (err < 0) {
 368                 oz_dbg(ON, "Failed to add cdev\n");
 369                 goto unregister;
 370         }
 371         g_oz_class = class_create(THIS_MODULE, "ozmo_wpan");
 372         if (IS_ERR(g_oz_class)) {
 373                 oz_dbg(ON, "Failed to register ozmo_wpan class\n");
 374                 err = PTR_ERR(g_oz_class);
 375                 goto delete;
 376         }
 377         dev = device_create(g_oz_class, NULL, g_cdev.devnum, NULL, "ozwpan");
 378         if (IS_ERR(dev)) {
 379                 oz_dbg(ON, "Failed to create sysfs entry for cdev\n");
 380                 err = PTR_ERR(dev);
 381                 goto delete;
 382         }
 383         return 0;
 384
 385 delete:
 386         cdev_del(&g_cdev.cdev);
 387 unregister:
 388         unregister_chrdev_region(g_cdev.devnum, 1);
 389         return err;
 390 }
 391
 392 /*
 393  * Context: process
 394  */
 395 int oz_cdev_deregister(void)
 396 {
 397         cdev_del(&g_cdev.cdev);
 398         unregister_chrdev_region(g_cdev.devnum, 1);
 399         if (g_oz_class) {
 400                 device_destroy(g_oz_class, g_cdev.devnum);
 401                 class_destroy(g_oz_class);
 402         }
 403         return 0;
 404 }
 405
 406 /*
 407  * Context: process
 408  */
 409 int oz_cdev_init(void)
 410 {
 411         oz_app_enable(OZ_APPID_SERIAL, 1);
 412         return 0;
 413 }
 414
 415 /*
 416  * Context: process
 417  */
 418 void oz_cdev_term(void)
 419 {
 420         oz_app_enable(OZ_APPID_SERIAL, 0);
 421 }
 422
 423 /*
 424  * Context: softirq-serialized
 425  */
 426 int oz_cdev_start(struct oz_pd *pd, int resume)
 427 {
 428         struct oz_serial_ctx *ctx;
 429         struct oz_serial_ctx *old_ctx;
 430
 431         if (resume) {
 432                 oz_dbg(ON, "Serial service resumed\n");
 433                 return 0;
 434         }
 435         ctx = kzalloc(sizeof(struct oz_serial_ctx), GFP_ATOMIC);
 436         if (ctx == NULL)
 437                 return -ENOMEM;
 438         atomic_set(&ctx->ref_count, 1);
 439         ctx->tx_seq_num = 1;
 440         spin_lock_bh(&pd->app_lock[OZ_APPID_SERIAL-1]);
 441         old_ctx = pd->app_ctx[OZ_APPID_SERIAL-1];
 442         if (old_ctx) {
 443                 spin_unlock_bh(&pd->app_lock[OZ_APPID_SERIAL-1]);
 444                 kfree(ctx);
 445         } else {
 446                 pd->app_ctx[OZ_APPID_SERIAL-1] = ctx;
 447                 spin_unlock_bh(&pd->app_lock[OZ_APPID_SERIAL-1]);
 448         }
 449         spin_lock(&g_cdev.lock);
 450         if ((g_cdev.active_pd == NULL) &&
 451                 ether_addr_equal(pd->mac_addr, g_cdev.active_addr)) {
 452                 oz_pd_get(pd);
 453                 g_cdev.active_pd = pd;
 454                 oz_dbg(ON, "Active PD arrived\n");
 455         }
 456         spin_unlock(&g_cdev.lock);
 457         oz_dbg(ON, "Serial service started\n");
 458         return 0;
 459 }
 460
 461 /*
 462  * Context: softirq or process
 463  */
 464 void oz_cdev_stop(struct oz_pd *pd, int pause)
 465 {
 466         struct oz_serial_ctx *ctx;
 467
 468         if (pause) {
 469                 oz_dbg(ON, "Serial service paused\n");
 470                 return;
 471         }
 472         spin_lock_bh(&pd->app_lock[OZ_APPID_SERIAL-1]);
 473         ctx = (struct oz_serial_ctx *)pd->app_ctx[OZ_APPID_SERIAL-1];
 474         pd->app_ctx[OZ_APPID_SERIAL-1] = NULL;
 475         spin_unlock_bh(&pd->app_lock[OZ_APPID_SERIAL-1]);
 476         if (ctx)
 477                 oz_cdev_release_ctx(ctx);
 478         spin_lock(&g_cdev.lock);
 479         if (pd == g_cdev.active_pd)
 480                 g_cdev.active_pd = NULL;
 481         else
 482                 pd = NULL;
 483         spin_unlock(&g_cdev.lock);
 484         if (pd) {
 485                 oz_pd_put(pd);
 486                 oz_dbg(ON, "Active PD departed\n");
 487         }
 488         oz_dbg(ON, "Serial service stopped\n");
 489 }
 490
 491 /*
 492  * Context: softirq-serialized
 493  */
 494 void oz_cdev_rx(struct oz_pd *pd, struct oz_elt *elt)
 495 {
 496         struct oz_serial_ctx *ctx;
 497         struct oz_app_hdr *app_hdr;
 498         u8 *data;
 499         int len;
 500         int space;
 501         int copy_sz;
 502         int ix;
 503
 504         ctx = oz_cdev_claim_ctx(pd);
 505         if (ctx == NULL) {
 506                 oz_dbg(ON, "Cannot claim serial context\n");
 507                 return;
 508         }
 509
 510         app_hdr = (struct oz_app_hdr *)(elt+1);
 511         /* If sequence number is non-zero then check it is not a duplicate.
 512          */
 513         if (app_hdr->elt_seq_num != 0) {
 514                 if (((ctx->rx_seq_num - app_hdr->elt_seq_num) & 0x80) == 0) {
 515                         /* Reject duplicate element. */
 516                         oz_dbg(ON, "Duplicate element:%02x %02x\n",
 517                                app_hdr->elt_seq_num, ctx->rx_seq_num);
 518                         goto out;
 519                 }
 520         }
 521         ctx->rx_seq_num = app_hdr->elt_seq_num;
 522         len = elt->length - sizeof(struct oz_app_hdr);
 523         data = ((u8 *)(elt+1)) + sizeof(struct oz_app_hdr);
 524         if (len <= 0)
 525                 goto out;
 526         space = ctx->rd_out - ctx->rd_in - 1;
 527         if (space < 0)
 528                 space += OZ_RD_BUF_SZ;
 529         if (len > space) {
 530                 oz_dbg(ON, "Not enough space:%d %d\n", len, space);
 531                 len = space;
 532         }
 533         ix = ctx->rd_in;
 534         copy_sz = OZ_RD_BUF_SZ - ix;
 535         if (copy_sz > len)
 536                 copy_sz = len;
 537         memcpy(&ctx->rd_buf[ix], data, copy_sz);
 538         len -= copy_sz;
 539         ix += copy_sz;
 540         if (ix == OZ_RD_BUF_SZ)
 541                 ix = 0;
 542         if (len) {
 543                 memcpy(ctx->rd_buf, data+copy_sz, len);
 544                 ix = len;
 545         }
 546         ctx->rd_in = ix;
 547         wake_up(&g_cdev.rdq);
 548 out:
 549         oz_cdev_release_ctx(ctx);
 550 }