arch/ia64/hp/sim/simeth.c

   1 /*
   2  * Simulated Ethernet Driver
   3  *
   4  * Copyright (C) 1999-2001, 2003 Hewlett-Packard Co
   5  *      Stephane Eranian <eranian@hpl.hp.com>
   6  */
   7 #include <linux/kernel.h>
   8 #include <linux/sched.h>
   9 #include <linux/types.h>
  10 #include <linux/in.h>
  11 #include <linux/string.h>
  12 #include <linux/init.h>
  13 #include <linux/errno.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/netdevice.h>
  16 #include <linux/etherdevice.h>
  17 #include <linux/inetdevice.h>
  18 #include <linux/if_ether.h>
  19 #include <linux/if_arp.h>
  20 #include <linux/skbuff.h>
  21 #include <linux/notifier.h>
  22 #include <linux/bitops.h>
  23 #include <asm/system.h>
  24 #include <asm/irq.h>
  25 #include <asm/hpsim.h>
  26
  27 #include "hpsim_ssc.h"
  28
  29 #define SIMETH_RECV_MAX 10
  30
  31 /*
  32  * Maximum possible received frame for Ethernet.
  33  * We preallocate an sk_buff of that size to avoid costly
  34  * memcpy for temporary buffer into sk_buff. We do basically
  35  * what's done in other drivers, like eepro with a ring.
  36  * The difference is, of course, that we don't have real DMA !!!
  37  */
  38 #define SIMETH_FRAME_SIZE       ETH_FRAME_LEN
  39
  40
  41 #define NETWORK_INTR                    8
  42
  43 struct simeth_local {
  44         struct net_device_stats stats;
  45         int                     simfd;   /* descriptor in the simulator */
  46 };
  47
  48 static int simeth_probe1(void);
  49 static int simeth_open(struct net_device *dev);
  50 static int simeth_close(struct net_device *dev);
  51 static int simeth_tx(struct sk_buff *skb, struct net_device *dev);
  52 static int simeth_rx(struct net_device *dev);
  53 static struct net_device_stats *simeth_get_stats(struct net_device *dev);
  54 static irqreturn_t simeth_interrupt(int irq, void *dev_id);
  55 static void set_multicast_list(struct net_device *dev);
  56 static int simeth_device_event(struct notifier_block *this,unsigned long event, void *ptr);
  57
  58 static char *simeth_version="0.3";
  59
  60 /*
  61  * This variable is used to establish a mapping between the Linux/ia64 kernel
  62  * and the host linux kernel.
  63  *
  64  * As of today, we support only one card, even though most of the code
  65  * is ready for many more. The mapping is then:
  66  *      linux/ia64 -> linux/x86
  67  *         eth0    -> eth1
  68  *
  69  * In the future, we some string operations, we could easily support up
  70  * to 10 cards (0-9).
  71  *
  72  * The default mapping can be changed on the kernel command line by
  73  * specifying simeth=ethX (or whatever string you want).
  74  */
  75 static char *simeth_device="eth0";       /* default host interface to use */
  76
  77
  78
  79 static volatile unsigned int card_count; /* how many cards "found" so far */
  80 static int simeth_debug;                /* set to 1 to get debug information */
  81
  82 /*
  83  * Used to catch IFF_UP & IFF_DOWN events
  84  */
  85 static struct notifier_block simeth_dev_notifier = {
  86         simeth_device_event,
  87         NULL
  88 };
  89
  90
  91 /*
  92  * Function used when using a kernel command line option.
  93  *
  94  * Format: simeth=interface_name (like eth0)
  95  */
  96 static int __init
  97 simeth_setup(char *str)
  98 {
  99         simeth_device = str;
 100         return 1;
 101 }
 102
 103 __setup("simeth=", simeth_setup);
 104
 105 /*
 106  * Function used to probe for simeth devices when not installed
 107  * as a loadable module
 108  */
 109
 110 int __init
 111 simeth_probe (void)
 112 {
 113         int r;
 114
 115         printk(KERN_INFO "simeth: v%s\n", simeth_version);
 116
 117         r = simeth_probe1();
 118
 119         if (r == 0) register_netdevice_notifier(&simeth_dev_notifier);
 120
 121         return r;
 122 }
 123
 124 static inline int
 125 netdev_probe(char *name, unsigned char *ether)
 126 {
 127         return ia64_ssc(__pa(name), __pa(ether), 0,0, SSC_NETDEV_PROBE);
 128 }
 129
 130
 131 static inline int
 132 netdev_connect(int irq)
 133 {
 134         /* XXX Fix me
 135          * this does not support multiple cards
 136          * also no return value
 137          */
 138         ia64_ssc_connect_irq(NETWORK_INTR, irq);
 139         return 0;
 140 }
 141
 142 static inline int
 143 netdev_attach(int fd, int irq, unsigned int ipaddr)
 144 {
 145         /* this puts the host interface in the right mode (start interrupting) */
 146         return ia64_ssc(fd, ipaddr, 0,0, SSC_NETDEV_ATTACH);
 147 }
 148
 149
 150 static inline int
 151 netdev_detach(int fd)
 152 {
 153         /*
 154          * inactivate the host interface (don't interrupt anymore) */
 155         return ia64_ssc(fd, 0,0,0, SSC_NETDEV_DETACH);
 156 }
 157
 158 static inline int
 159 netdev_send(int fd, unsigned char *buf, unsigned int len)
 160 {
 161         return ia64_ssc(fd, __pa(buf), len, 0, SSC_NETDEV_SEND);
 162 }
 163
 164 static inline int
 165 netdev_read(int fd, unsigned char *buf, unsigned int len)
 166 {
 167         return ia64_ssc(fd, __pa(buf), len, 0, SSC_NETDEV_RECV);
 168 }
 169
 170 /*
 171  * Function shared with module code, so cannot be in init section
 172  *
 173  * So far this function "detects" only one card (test_&_set) but could
 174  * be extended easily.
 175  *
 176  * Return:
 177  *      - -ENODEV is no device found
 178  *      - -ENOMEM is no more memory
 179  *      - 0 otherwise
 180  */
 181 static int
 182 simeth_probe1(void)
 183 {
 184         unsigned char mac_addr[ETH_ALEN];
 185         struct simeth_local *local;
 186         struct net_device *dev;
 187         int fd, i, err, rc;
 188
 189         /*
 190          * XXX Fix me
 191          * let's support just one card for now
 192          */
 193         if (test_and_set_bit(0, &card_count))
 194                 return -ENODEV;
 195
 196         /*
 197          * check with the simulator for the device
 198          */
 199         fd = netdev_probe(simeth_device, mac_addr);
 200         if (fd == -1)
 201                 return -ENODEV;
 202
 203         dev = alloc_etherdev(sizeof(struct simeth_local));
 204         if (!dev)
 205                 return -ENOMEM;
 206
 207         memcpy(dev->dev_addr, mac_addr, sizeof(mac_addr));
 208
 209         local = dev->priv;
 210         local->simfd = fd; /* keep track of underlying file descriptor */
 211
 212         dev->open               = simeth_open;
 213         dev->stop               = simeth_close;
 214         dev->hard_start_xmit    = simeth_tx;
 215         dev->get_stats          = simeth_get_stats;
 216         dev->set_multicast_list = set_multicast_list; /* no yet used */
 217
 218         err = register_netdev(dev);
 219         if (err) {
 220                 free_netdev(dev);
 221                 return err;
 222         }
 223
 224         if ((rc = assign_irq_vector(AUTO_ASSIGN)) < 0)
 225                 panic("%s: out of interrupt vectors!\n", __FUNCTION__);
 226         dev->irq = rc;
 227
 228         /*
 229          * attach the interrupt in the simulator, this does enable interrupts
 230          * until a netdev_attach() is called
 231          */
 232         netdev_connect(dev->irq);
 233
 234         printk(KERN_INFO "%s: hosteth=%s simfd=%d, HwAddr",
 235                dev->name, simeth_device, local->simfd);
 236         for(i = 0; i < ETH_ALEN; i++) {
 237                 printk(" %2.2x", dev->dev_addr[i]);
 238         }
 239         printk(", IRQ %d\n", dev->irq);
 240
 241         return 0;
 242 }
 243
 244 /*
 245  * actually binds the device to an interrupt vector
 246  */
 247 static int
 248 simeth_open(struct net_device *dev)
 249 {
 250         if (request_irq(dev->irq, simeth_interrupt, 0, "simeth", dev)) {
 251                 printk(KERN_WARNING "simeth: unable to get IRQ %d.\n", dev->irq);
 252                 return -EAGAIN;
 253         }
 254
 255         netif_start_queue(dev);
 256
 257         return 0;
 258 }
 259
 260 /* copied from lapbether.c */
 261 static __inline__ int dev_is_ethdev(struct net_device *dev)
 262 {
 263        return ( dev->type == ARPHRD_ETHER && strncmp(dev->name, "dummy", 5));
 264 }
 265
 266
 267 /*
 268  * Handler for IFF_UP or IFF_DOWN
 269  *
 270  * The reason for that is that we don't want to be interrupted when the
 271  * interface is down. There is no way to unconnect in the simualtor. Instead
 272  * we use this function to shutdown packet processing in the frame filter
 273  * in the simulator. Thus no interrupts are generated
 274  *
 275  *
 276  * That's also the place where we pass the IP address of this device to the
 277  * simulator so that that we can start filtering packets for it
 278  *
 279  * There may be a better way of doing this, but I don't know which yet.
 280  */
 281 static int
 282 simeth_device_event(struct notifier_block *this,unsigned long event, void *ptr)
 283 {
 284         struct net_device *dev = ptr;
 285         struct simeth_local *local;
 286         struct in_device *in_dev;
 287         struct in_ifaddr **ifap = NULL;
 288         struct in_ifaddr *ifa = NULL;
 289         int r;
 290
 291
 292         if ( ! dev ) {
 293                 printk(KERN_WARNING "simeth_device_event dev=0\n");
 294                 return NOTIFY_DONE;
 295         }
 296
 297         if (dev->nd_net != &init_net)
 298                 return NOTIFY_DONE;
 299
 300         if ( event != NETDEV_UP && event != NETDEV_DOWN ) return NOTIFY_DONE;
 301
 302         /*
 303          * Check whether or not it's for an ethernet device
 304          *
 305          * XXX Fixme: This works only as long as we support one
 306          * type of ethernet device.
 307          */
 308         if ( !dev_is_ethdev(dev) ) return NOTIFY_DONE;
 309
 310         if ((in_dev=dev->ip_ptr) != NULL) {
 311                 for (ifap=&in_dev->ifa_list; (ifa=*ifap) != NULL; ifap=&ifa->ifa_next)
 312                         if (strcmp(dev->name, ifa->ifa_label) == 0) break;
 313         }
 314         if ( ifa == NULL ) {
 315                 printk(KERN_ERR "simeth_open: can't find device %s's ifa\n", dev->name);
 316                 return NOTIFY_DONE;
 317         }
 318
 319         printk(KERN_INFO "simeth_device_event: %s ipaddr=0x%x\n",
 320                dev->name, ntohl(ifa->ifa_local));
 321
 322         /*
 323          * XXX Fix me
 324          * if the device was up, and we're simply reconfiguring it, not sure
 325          * we get DOWN then UP.
 326          */
 327
 328         local = dev->priv;
 329         /* now do it for real */
 330         r = event == NETDEV_UP ?
 331                 netdev_attach(local->simfd, dev->irq, ntohl(ifa->ifa_local)):
 332                 netdev_detach(local->simfd);
 333
 334         printk(KERN_INFO "simeth: netdev_attach/detach: event=%s ->%d\n",
 335                event == NETDEV_UP ? "attach":"detach", r);
 336
 337         return NOTIFY_DONE;
 338 }
 339
 340 static int
 341 simeth_close(struct net_device *dev)
 342 {
 343         netif_stop_queue(dev);
 344
 345         free_irq(dev->irq, dev);
 346
 347         return 0;
 348 }
 349
 350 /*
 351  * Only used for debug
 352  */
 353 static void
 354 frame_print(unsigned char *from, unsigned char *frame, int len)
 355 {
 356         int i;
 357
 358         printk("%s: (%d) %02x", from, len, frame[0] & 0xff);
 359         for(i=1; i < 6; i++ ) {
 360                 printk(":%02x", frame[i] &0xff);
 361         }
 362         printk(" %2x", frame[6] &0xff);
 363         for(i=7; i < 12; i++ ) {
 364                 printk(":%02x", frame[i] &0xff);
 365         }
 366         printk(" [%02x%02x]\n", frame[12], frame[13]);
 367
 368         for(i=14; i < len; i++ ) {
 369                 printk("%02x ", frame[i] &0xff);
 370                 if ( (i%10)==0) printk("\n");
 371         }
 372         printk("\n");
 373 }
 374
 375
 376 /*
 377  * Function used to transmit of frame, very last one on the path before
 378  * going to the simulator.
 379  */
 380 static int
 381 simeth_tx(struct sk_buff *skb, struct net_device *dev)
 382 {
 383         struct simeth_local *local = dev->priv;
 384
 385 #if 0
 386         /* ensure we have at least ETH_ZLEN bytes (min frame size) */
 387         unsigned int length = ETH_ZLEN < skb->len ? skb->len : ETH_ZLEN;
 388         /* Where do the extra padding bytes comes from inthe skbuff ? */
 389 #else
 390         /* the real driver in the host system is going to take care of that
 391          * or maybe it's the NIC itself.
 392          */
 393         unsigned int length = skb->len;
 394 #endif
 395
 396         local->stats.tx_bytes += skb->len;
 397         local->stats.tx_packets++;
 398
 399
 400         if (simeth_debug > 5) frame_print("simeth_tx", skb->data, length);
 401
 402         netdev_send(local->simfd, skb->data, length);
 403
 404         /*
 405          * we are synchronous on write, so we don't simulate a
 406          * trasnmit complete interrupt, thus we don't need to arm a tx
 407          */
 408
 409         dev_kfree_skb(skb);
 410         return 0;
 411 }
 412
 413 static inline struct sk_buff *
 414 make_new_skb(struct net_device *dev)
 415 {
 416         struct sk_buff *nskb;
 417
 418         /*
 419          * The +2 is used to make sure that the IP header is nicely
 420          * aligned (on 4byte boundary I assume 14+2=16)
 421          */
 422         nskb = dev_alloc_skb(SIMETH_FRAME_SIZE + 2);
 423         if ( nskb == NULL ) {
 424                 printk(KERN_NOTICE "%s: memory squeeze. dropping packet.\n", dev->name);
 425                 return NULL;
 426         }
 427
 428         skb_reserve(nskb, 2);   /* Align IP on 16 byte boundaries */
 429
 430         skb_put(nskb,SIMETH_FRAME_SIZE);
 431
 432         return nskb;
 433 }
 434
 435 /*
 436  * called from interrupt handler to process a received frame
 437  */
 438 static int
 439 simeth_rx(struct net_device *dev)
 440 {
 441         struct simeth_local     *local;
 442         struct sk_buff          *skb;
 443         int                     len;
 444         int                     rcv_count = SIMETH_RECV_MAX;
 445
 446         local = dev->priv;
 447         /*
 448          * the loop concept has been borrowed from other drivers
 449          * looks to me like it's a throttling thing to avoid pushing to many
 450          * packets at one time into the stack. Making sure we can process them
 451          * upstream and make forward progress overall
 452          */
 453         do {
 454                 if ( (skb=make_new_skb(dev)) == NULL ) {
 455                         printk(KERN_NOTICE "%s: memory squeeze. dropping packet.\n", dev->name);
 456                         local->stats.rx_dropped++;
 457                         return 0;
 458                 }
 459                 /*
 460                  * Read only one frame at a time
 461                  */
 462                 len = netdev_read(local->simfd, skb->data, SIMETH_FRAME_SIZE);
 463                 if ( len == 0 ) {
 464                         if ( simeth_debug > 0 ) printk(KERN_WARNING "%s: count=%d netdev_read=0\n",
 465                                                        dev->name, SIMETH_RECV_MAX-rcv_count);
 466                         break;
 467                 }
 468 #if 0
 469                 /*
 470                  * XXX Fix me
 471                  * Should really do a csum+copy here
 472                  */
 473                 skb_copy_to_linear_data(skb, frame, len);
 474 #endif
 475                 skb->protocol = eth_type_trans(skb, dev);
 476
 477                 if ( simeth_debug > 6 ) frame_print("simeth_rx", skb->data, len);
 478
 479                 /*
 480                  * push the packet up & trigger software interrupt
 481                  */
 482                 netif_rx(skb);
 483
 484                 local->stats.rx_packets++;
 485                 local->stats.rx_bytes += len;
 486
 487         } while ( --rcv_count );
 488
 489         return len; /* 0 = nothing left to read, otherwise, we can try again */
 490 }
 491
 492 /*
 493  * Interrupt handler (Yes, we can do it too !!!)
 494  */
 495 static irqreturn_t
 496 simeth_interrupt(int irq, void *dev_id)
 497 {
 498         struct net_device *dev = dev_id;
 499
 500         if ( dev == NULL ) {
 501                 printk(KERN_WARNING "simeth: irq %d for unknown device\n", irq);
 502                 return IRQ_NONE;
 503         }
 504
 505         /*
 506          * very simple loop because we get interrupts only when receiving
 507          */
 508         while (simeth_rx(dev));
 509         return IRQ_HANDLED;
 510 }
 511
 512 static struct net_device_stats *
 513 simeth_get_stats(struct net_device *dev)
 514 {
 515         struct simeth_local *local = dev->priv;
 516
 517         return &local->stats;
 518 }
 519
 520 /* fake multicast ability */
 521 static void
 522 set_multicast_list(struct net_device *dev)
 523 {
 524         printk(KERN_WARNING "%s: set_multicast_list called\n", dev->name);
 525 }
 526
 527 __initcall(simeth_probe);