xref: /openbmc/qemu/hw/net/i82596.c (revision f76b348e)
1 /*
2  * QEMU Intel i82596 (Apricot) emulation
3  *
4  * Copyright (c) 2019 Helge Deller <deller@gmx.de>
5  * This work is licensed under the GNU GPL license version 2 or later.
6  *
7  * This software was written to be compatible with the specification:
8  * https://www.intel.com/assets/pdf/general/82596ca.pdf
9  */
10 
11 #include "qemu/osdep.h"
12 #include "qemu/timer.h"
13 #include "net/net.h"
14 #include "net/eth.h"
15 #include "sysemu/sysemu.h"
16 #include "hw/irq.h"
17 #include "hw/qdev-properties.h"
18 #include "migration/vmstate.h"
19 #include "qemu/module.h"
20 #include "trace.h"
21 #include "i82596.h"
22 #include <zlib.h>       /* For crc32 */
23 
24 #if defined(ENABLE_DEBUG)
25 #define DBG(x)          x
26 #else
27 #define DBG(x)          do { } while (0)
28 #endif
29 
30 #define USE_TIMER       0
31 
32 #define BITS(n, m) (((0xffffffffU << (31 - n)) >> (31 - n + m)) << m)
33 
34 #define PKT_BUF_SZ      1536
35 #define MAX_MC_CNT      64
36 
37 #define ISCP_BUSY       0x0001
38 
39 #define I596_NULL       ((uint32_t)0xffffffff)
40 
41 #define SCB_STATUS_CX   0x8000 /* CU finished command with I bit */
42 #define SCB_STATUS_FR   0x4000 /* RU finished receiving a frame */
43 #define SCB_STATUS_CNA  0x2000 /* CU left active state */
44 #define SCB_STATUS_RNR  0x1000 /* RU left active state */
45 
46 #define SCB_COMMAND_ACK_MASK \
47         (SCB_STATUS_CX | SCB_STATUS_FR | SCB_STATUS_CNA | SCB_STATUS_RNR)
48 
49 #define CU_IDLE         0
50 #define CU_SUSPENDED    1
51 #define CU_ACTIVE       2
52 
53 #define RX_IDLE         0
54 #define RX_SUSPENDED    1
55 #define RX_READY        4
56 
57 #define CMD_EOL         0x8000  /* The last command of the list, stop. */
58 #define CMD_SUSP        0x4000  /* Suspend after doing cmd. */
59 #define CMD_INTR        0x2000  /* Interrupt after doing cmd. */
60 
61 #define CMD_FLEX        0x0008  /* Enable flexible memory model */
62 
63 enum commands {
64         CmdNOp = 0, CmdSASetup = 1, CmdConfigure = 2, CmdMulticastList = 3,
65         CmdTx = 4, CmdTDR = 5, CmdDump = 6, CmdDiagnose = 7
66 };
67 
68 #define STAT_C          0x8000  /* Set to 0 after execution */
69 #define STAT_B          0x4000  /* Command being executed */
70 #define STAT_OK         0x2000  /* Command executed ok */
71 #define STAT_A          0x1000  /* Command aborted */
72 
73 #define I596_EOF        0x8000
74 #define SIZE_MASK       0x3fff
75 
76 #define ETHER_TYPE_LEN 2
77 #define VLAN_TCI_LEN 2
78 #define VLAN_HLEN (ETHER_TYPE_LEN + VLAN_TCI_LEN)
79 
80 /* various flags in the chip config registers */
81 #define I596_PREFETCH   (s->config[0] & 0x80)
82 #define I596_PROMISC    (s->config[8] & 0x01)
83 #define I596_BC_DISABLE (s->config[8] & 0x02) /* broadcast disable */
84 #define I596_NOCRC_INS  (s->config[8] & 0x08)
85 #define I596_CRCINM     (s->config[11] & 0x04) /* CRC appended */
86 #define I596_MC_ALL     (s->config[11] & 0x20)
87 #define I596_MULTIIA    (s->config[13] & 0x40)
88 
89 
90 static uint8_t get_byte(uint32_t addr)
91 {
92     return ldub_phys(&address_space_memory, addr);
93 }
94 
95 static void set_byte(uint32_t addr, uint8_t c)
96 {
97     return stb_phys(&address_space_memory, addr, c);
98 }
99 
100 static uint16_t get_uint16(uint32_t addr)
101 {
102     return lduw_be_phys(&address_space_memory, addr);
103 }
104 
105 static void set_uint16(uint32_t addr, uint16_t w)
106 {
107     return stw_be_phys(&address_space_memory, addr, w);
108 }
109 
110 static uint32_t get_uint32(uint32_t addr)
111 {
112     uint32_t lo = lduw_be_phys(&address_space_memory, addr);
113     uint32_t hi = lduw_be_phys(&address_space_memory, addr + 2);
114     return (hi << 16) | lo;
115 }
116 
117 static void set_uint32(uint32_t addr, uint32_t val)
118 {
119     set_uint16(addr, (uint16_t) val);
120     set_uint16(addr + 2, val >> 16);
121 }
122 
123 
124 struct qemu_ether_header {
125     uint8_t ether_dhost[6];
126     uint8_t ether_shost[6];
127     uint16_t ether_type;
128 };
129 
130 #define PRINT_PKTHDR(txt, BUF) do {                  \
131     struct qemu_ether_header *hdr = (void *)(BUF); \
132     printf(txt ": packet dhost=" MAC_FMT ", shost=" MAC_FMT ", type=0x%04x\n",\
133            MAC_ARG(hdr->ether_dhost), MAC_ARG(hdr->ether_shost),        \
134            be16_to_cpu(hdr->ether_type));       \
135 } while (0)
136 
137 static void i82596_transmit(I82596State *s, uint32_t addr)
138 {
139     uint32_t tdb_p; /* Transmit Buffer Descriptor */
140 
141     /* TODO: Check flexible mode */
142     tdb_p = get_uint32(addr + 8);
143     while (tdb_p != I596_NULL) {
144         uint16_t size, len;
145         uint32_t tba;
146 
147         size = get_uint16(tdb_p);
148         len = size & SIZE_MASK;
149         tba = get_uint32(tdb_p + 8);
150         trace_i82596_transmit(len, tba);
151 
152         if (s->nic && len) {
153             assert(len <= sizeof(s->tx_buffer));
154             address_space_read(&address_space_memory, tba,
155                                MEMTXATTRS_UNSPECIFIED, s->tx_buffer, len);
156             DBG(PRINT_PKTHDR("Send", &s->tx_buffer));
157             DBG(printf("Sending %d bytes\n", len));
158             qemu_send_packet(qemu_get_queue(s->nic), s->tx_buffer, len);
159         }
160 
161         /* was this the last package? */
162         if (size & I596_EOF) {
163             break;
164         }
165 
166         /* get next buffer pointer */
167         tdb_p = get_uint32(tdb_p + 4);
168     }
169 }
170 
171 static void set_individual_address(I82596State *s, uint32_t addr)
172 {
173     NetClientState *nc;
174     uint8_t *m;
175 
176     nc = qemu_get_queue(s->nic);
177     m = s->conf.macaddr.a;
178     address_space_read(&address_space_memory, addr + 8,
179                        MEMTXATTRS_UNSPECIFIED, m, ETH_ALEN);
180     qemu_format_nic_info_str(nc, m);
181     trace_i82596_new_mac(nc->info_str);
182 }
183 
184 static void set_multicast_list(I82596State *s, uint32_t addr)
185 {
186     uint16_t mc_count, i;
187 
188     memset(&s->mult[0], 0, sizeof(s->mult));
189     mc_count = get_uint16(addr + 8) / ETH_ALEN;
190     addr += 10;
191     if (mc_count > MAX_MC_CNT) {
192         mc_count = MAX_MC_CNT;
193     }
194     for (i = 0; i < mc_count; i++) {
195         uint8_t multicast_addr[ETH_ALEN];
196         address_space_read(&address_space_memory, addr + i * ETH_ALEN,
197                            MEMTXATTRS_UNSPECIFIED, multicast_addr, ETH_ALEN);
198         DBG(printf("Add multicast entry " MAC_FMT "\n",
199                     MAC_ARG(multicast_addr)));
200         unsigned mcast_idx = (net_crc32(multicast_addr, ETH_ALEN) &
201                               BITS(7, 2)) >> 2;
202         assert(mcast_idx < 8 * sizeof(s->mult));
203         s->mult[mcast_idx >> 3] |= (1 << (mcast_idx & 7));
204     }
205     trace_i82596_set_multicast(mc_count);
206 }
207 
208 void i82596_set_link_status(NetClientState *nc)
209 {
210     I82596State *d = qemu_get_nic_opaque(nc);
211 
212     d->lnkst = nc->link_down ? 0 : 0x8000;
213 }
214 
215 static void update_scb_status(I82596State *s)
216 {
217     s->scb_status = (s->scb_status & 0xf000)
218         | (s->cu_status << 8) | (s->rx_status << 4);
219     set_uint16(s->scb, s->scb_status);
220 }
221 
222 
223 static void i82596_s_reset(I82596State *s)
224 {
225     trace_i82596_s_reset(s);
226     s->scp = 0;
227     s->scb_status = 0;
228     s->cu_status = CU_IDLE;
229     s->rx_status = RX_SUSPENDED;
230     s->cmd_p = I596_NULL;
231     s->lnkst = 0x8000; /* initial link state: up */
232     s->ca = s->ca_active = 0;
233     s->send_irq = 0;
234 }
235 
236 
237 static void command_loop(I82596State *s)
238 {
239     uint16_t cmd;
240     uint16_t status;
241     uint8_t byte_cnt;
242 
243     DBG(printf("STARTING COMMAND LOOP cmd_p=%08x\n", s->cmd_p));
244 
245     while (s->cmd_p != I596_NULL) {
246         /* set status */
247         status = STAT_B;
248         set_uint16(s->cmd_p, status);
249         status = STAT_C | STAT_OK; /* update, but write later */
250 
251         cmd = get_uint16(s->cmd_p + 2);
252         DBG(printf("Running command %04x at %08x\n", cmd, s->cmd_p));
253 
254         switch (cmd & 0x07) {
255         case CmdNOp:
256             break;
257         case CmdSASetup:
258             set_individual_address(s, s->cmd_p);
259             break;
260         case CmdConfigure:
261             byte_cnt = get_byte(s->cmd_p + 8) & 0x0f;
262             byte_cnt = MAX(byte_cnt, 4);
263             byte_cnt = MIN(byte_cnt, sizeof(s->config));
264             /* copy byte_cnt max. */
265             address_space_read(&address_space_memory, s->cmd_p + 8,
266                                MEMTXATTRS_UNSPECIFIED, s->config, byte_cnt);
267             /* config byte according to page 35ff */
268             s->config[2] &= 0x82; /* mask valid bits */
269             s->config[2] |= 0x40;
270             s->config[7]  &= 0xf7; /* clear zero bit */
271             assert(I596_NOCRC_INS == 0); /* do CRC insertion */
272             s->config[10] = MAX(s->config[10], 5); /* min frame length */
273             s->config[12] &= 0x40; /* only full duplex field valid */
274             s->config[13] |= 0x3f; /* set ones in byte 13 */
275             break;
276         case CmdTDR:
277             /* get signal LINK */
278             set_uint32(s->cmd_p + 8, s->lnkst);
279             break;
280         case CmdTx:
281             i82596_transmit(s, s->cmd_p);
282             break;
283         case CmdMulticastList:
284             set_multicast_list(s, s->cmd_p);
285             break;
286         case CmdDump:
287         case CmdDiagnose:
288             printf("FIXME Command %d !!\n", cmd & 7);
289             assert(0);
290         }
291 
292         /* update status */
293         set_uint16(s->cmd_p, status);
294 
295         s->cmd_p = get_uint32(s->cmd_p + 4); /* get link address */
296         DBG(printf("NEXT addr would be %08x\n", s->cmd_p));
297         if (s->cmd_p == 0) {
298             s->cmd_p = I596_NULL;
299         }
300 
301         /* Stop when last command of the list. */
302         if (cmd & CMD_EOL) {
303             s->cmd_p = I596_NULL;
304         }
305         /* Suspend after doing cmd? */
306         if (cmd & CMD_SUSP) {
307             s->cu_status = CU_SUSPENDED;
308             printf("FIXME SUSPEND !!\n");
309         }
310         /* Interrupt after doing cmd? */
311         if (cmd & CMD_INTR) {
312             s->scb_status |= SCB_STATUS_CX;
313         } else {
314             s->scb_status &= ~SCB_STATUS_CX;
315         }
316         update_scb_status(s);
317 
318         /* Interrupt after doing cmd? */
319         if (cmd & CMD_INTR) {
320             s->send_irq = 1;
321         }
322 
323         if (s->cu_status != CU_ACTIVE) {
324             break;
325         }
326     }
327     DBG(printf("FINISHED COMMAND LOOP\n"));
328     qemu_flush_queued_packets(qemu_get_queue(s->nic));
329 }
330 
331 static void i82596_flush_queue_timer(void *opaque)
332 {
333     I82596State *s = opaque;
334     if (0) {
335         timer_del(s->flush_queue_timer);
336         qemu_flush_queued_packets(qemu_get_queue(s->nic));
337         timer_mod(s->flush_queue_timer,
338               qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 1000);
339     }
340 }
341 
342 static void examine_scb(I82596State *s)
343 {
344     uint16_t command, cuc, ruc;
345 
346     /* get the scb command word */
347     command = get_uint16(s->scb + 2);
348     cuc = (command >> 8) & 0x7;
349     ruc = (command >> 4) & 0x7;
350     DBG(printf("MAIN COMMAND %04x  cuc %02x ruc %02x\n", command, cuc, ruc));
351     /* and clear the scb command word */
352     set_uint16(s->scb + 2, 0);
353 
354     s->scb_status &= ~(command & SCB_COMMAND_ACK_MASK);
355 
356     switch (cuc) {
357     case 0:     /* no change */
358         break;
359     case 1:     /* CUC_START */
360         s->cu_status = CU_ACTIVE;
361         break;
362     case 4:     /* CUC_ABORT */
363         s->cu_status = CU_SUSPENDED;
364         s->scb_status |= SCB_STATUS_CNA; /* CU left active state */
365         break;
366     default:
367         printf("WARNING: Unknown CUC %d!\n", cuc);
368     }
369 
370     switch (ruc) {
371     case 0:     /* no change */
372         break;
373     case 1:     /* RX_START */
374     case 2:     /* RX_RESUME */
375         s->rx_status = RX_IDLE;
376         if (USE_TIMER) {
377             timer_mod(s->flush_queue_timer, qemu_clock_get_ms(
378                                 QEMU_CLOCK_VIRTUAL) + 1000);
379         }
380         break;
381     case 3:     /* RX_SUSPEND */
382     case 4:     /* RX_ABORT */
383         s->rx_status = RX_SUSPENDED;
384         s->scb_status |= SCB_STATUS_RNR; /* RU left active state */
385         break;
386     default:
387         printf("WARNING: Unknown RUC %d!\n", ruc);
388     }
389 
390     if (command & 0x80) { /* reset bit set? */
391         i82596_s_reset(s);
392     }
393 
394     /* execute commands from SCBL */
395     if (s->cu_status != CU_SUSPENDED) {
396         if (s->cmd_p == I596_NULL) {
397             s->cmd_p = get_uint32(s->scb + 4);
398         }
399     }
400 
401     /* update scb status */
402     update_scb_status(s);
403 
404     command_loop(s);
405 }
406 
407 static void signal_ca(I82596State *s)
408 {
409     uint32_t iscp = 0;
410 
411     /* trace_i82596_channel_attention(s); */
412     if (s->scp) {
413         /* CA after reset -> do init with new scp. */
414         s->sysbus = get_byte(s->scp + 3); /* big endian */
415         DBG(printf("SYSBUS = %08x\n", s->sysbus));
416         if (((s->sysbus >> 1) & 0x03) != 2) {
417             printf("WARNING: NO LINEAR MODE !!\n");
418         }
419         if ((s->sysbus >> 7)) {
420             printf("WARNING: 32BIT LINMODE IN B-STEPPING NOT SUPPORTED !!\n");
421         }
422         iscp = get_uint32(s->scp + 8);
423         s->scb = get_uint32(iscp + 4);
424         set_byte(iscp + 1, 0); /* clear BUSY flag in iscp */
425         s->scp = 0;
426     }
427 
428     s->ca++;    /* count ca() */
429     if (!s->ca_active) {
430         s->ca_active = 1;
431         while (s->ca)   {
432             examine_scb(s);
433             s->ca--;
434         }
435         s->ca_active = 0;
436     }
437 
438     if (s->send_irq) {
439         s->send_irq = 0;
440         qemu_set_irq(s->irq, 1);
441     }
442 }
443 
444 void i82596_ioport_writew(void *opaque, uint32_t addr, uint32_t val)
445 {
446     I82596State *s = opaque;
447     /* printf("i82596_ioport_writew addr=0x%08x val=0x%04x\n", addr, val); */
448     switch (addr) {
449     case PORT_RESET: /* Reset */
450         i82596_s_reset(s);
451         break;
452     case PORT_ALTSCP:
453         s->scp = val;
454         break;
455     case PORT_CA:
456         signal_ca(s);
457         break;
458     }
459 }
460 
461 uint32_t i82596_ioport_readw(void *opaque, uint32_t addr)
462 {
463     return -1;
464 }
465 
466 void i82596_h_reset(void *opaque)
467 {
468     I82596State *s = opaque;
469 
470     i82596_s_reset(s);
471 }
472 
473 bool i82596_can_receive(NetClientState *nc)
474 {
475     I82596State *s = qemu_get_nic_opaque(nc);
476 
477     if (s->rx_status == RX_SUSPENDED) {
478         return false;
479     }
480 
481     if (!s->lnkst) {
482         return false;
483     }
484 
485     if (USE_TIMER && !timer_pending(s->flush_queue_timer)) {
486         return true;
487     }
488 
489     return true;
490 }
491 
492 #define MIN_BUF_SIZE 60
493 
494 ssize_t i82596_receive(NetClientState *nc, const uint8_t *buf, size_t sz)
495 {
496     I82596State *s = qemu_get_nic_opaque(nc);
497     uint32_t rfd_p;
498     uint32_t rbd;
499     uint16_t is_broadcast = 0;
500     size_t len = sz; /* length of data for guest (including CRC) */
501     size_t bufsz = sz; /* length of data in buf */
502     uint32_t crc;
503     uint8_t *crc_ptr;
504     uint8_t buf1[MIN_BUF_SIZE + VLAN_HLEN];
505     static const uint8_t broadcast_macaddr[6] = {
506                 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
507 
508     DBG(printf("i82596_receive() start\n"));
509 
510     if (USE_TIMER && timer_pending(s->flush_queue_timer)) {
511         return 0;
512     }
513 
514     /* first check if receiver is enabled */
515     if (s->rx_status == RX_SUSPENDED) {
516         trace_i82596_receive_analysis(">>> Receiving suspended");
517         return -1;
518     }
519 
520     if (!s->lnkst) {
521         trace_i82596_receive_analysis(">>> Link down");
522         return -1;
523     }
524 
525     /* Received frame smaller than configured "min frame len"? */
526     if (sz < s->config[10]) {
527         printf("Received frame too small, %zu vs. %u bytes\n",
528                sz, s->config[10]);
529         return -1;
530     }
531 
532     DBG(printf("Received %lu bytes\n", sz));
533 
534     if (I596_PROMISC) {
535 
536         /* promiscuous: receive all */
537         trace_i82596_receive_analysis(
538                 ">>> packet received in promiscuous mode");
539 
540     } else {
541 
542         if (!memcmp(buf,  broadcast_macaddr, 6)) {
543             /* broadcast address */
544             if (I596_BC_DISABLE) {
545                 trace_i82596_receive_analysis(">>> broadcast packet rejected");
546 
547                 return len;
548             }
549 
550             trace_i82596_receive_analysis(">>> broadcast packet received");
551             is_broadcast = 1;
552 
553         } else if (buf[0] & 0x01) {
554             /* multicast */
555             if (!I596_MC_ALL) {
556                 trace_i82596_receive_analysis(">>> multicast packet rejected");
557 
558                 return len;
559             }
560 
561             int mcast_idx = (net_crc32(buf, ETH_ALEN) & BITS(7, 2)) >> 2;
562             assert(mcast_idx < 8 * sizeof(s->mult));
563 
564             if (!(s->mult[mcast_idx >> 3] & (1 << (mcast_idx & 7)))) {
565                 trace_i82596_receive_analysis(">>> multicast address mismatch");
566 
567                 return len;
568             }
569 
570             trace_i82596_receive_analysis(">>> multicast packet received");
571             is_broadcast = 1;
572 
573         } else if (!memcmp(s->conf.macaddr.a, buf, 6)) {
574 
575             /* match */
576             trace_i82596_receive_analysis(
577                     ">>> physical address matching packet received");
578 
579         } else {
580 
581             trace_i82596_receive_analysis(">>> unknown packet");
582 
583             return len;
584         }
585     }
586 
587     /* if too small buffer, then expand it */
588     if (len < MIN_BUF_SIZE + VLAN_HLEN) {
589         memcpy(buf1, buf, len);
590         memset(buf1 + len, 0, MIN_BUF_SIZE + VLAN_HLEN - len);
591         buf = buf1;
592         if (len < MIN_BUF_SIZE) {
593             len = MIN_BUF_SIZE;
594         }
595         bufsz = len;
596     }
597 
598     /* Calculate the ethernet checksum (4 bytes) */
599     len += 4;
600     crc = cpu_to_be32(crc32(~0, buf, sz));
601     crc_ptr = (uint8_t *) &crc;
602 
603     rfd_p = get_uint32(s->scb + 8); /* get Receive Frame Descriptor */
604     assert(rfd_p && rfd_p != I596_NULL);
605 
606     /* get first Receive Buffer Descriptor Address */
607     rbd = get_uint32(rfd_p + 8);
608     assert(rbd && rbd != I596_NULL);
609 
610     trace_i82596_receive_packet(len);
611     /* PRINT_PKTHDR("Receive", buf); */
612 
613     while (len) {
614         uint16_t command, status;
615         uint32_t next_rfd;
616 
617         command = get_uint16(rfd_p + 2);
618         assert(command & CMD_FLEX); /* assert Flex Mode */
619         /* get first Receive Buffer Descriptor Address */
620         rbd = get_uint32(rfd_p + 8);
621         assert(get_uint16(rfd_p + 14) == 0);
622 
623         /* printf("Receive: rfd is %08x\n", rfd_p); */
624 
625         while (len) {
626             uint16_t buffer_size, num;
627             uint32_t rba;
628             size_t bufcount, crccount;
629 
630             /* printf("Receive: rbd is %08x\n", rbd); */
631             buffer_size = get_uint16(rbd + 12);
632             /* printf("buffer_size is 0x%x\n", buffer_size); */
633             assert(buffer_size != 0);
634 
635             num = buffer_size & SIZE_MASK;
636             if (num > len) {
637                 num = len;
638             }
639             rba = get_uint32(rbd + 8);
640             /* printf("rba is 0x%x\n", rba); */
641             /*
642              * Calculate how many bytes we want from buf[] and how many
643              * from the CRC.
644              */
645             if ((len - num) >= 4) {
646                 /* The whole guest buffer, we haven't hit the CRC yet */
647                 bufcount = num;
648             } else {
649                 /* All that's left of buf[] */
650                 bufcount = len - 4;
651             }
652             crccount = num - bufcount;
653 
654             if (bufcount > 0) {
655                 /* Still some of the actual data buffer to transfer */
656                 assert(bufsz >= bufcount);
657                 bufsz -= bufcount;
658                 address_space_write(&address_space_memory, rba,
659                                     MEMTXATTRS_UNSPECIFIED, buf, bufcount);
660                 rba += bufcount;
661                 buf += bufcount;
662                 len -= bufcount;
663             }
664 
665             /* Write as much of the CRC as fits */
666             if (crccount > 0) {
667                 address_space_write(&address_space_memory, rba,
668                                     MEMTXATTRS_UNSPECIFIED, crc_ptr, crccount);
669                 rba += crccount;
670                 crc_ptr += crccount;
671                 len -= crccount;
672             }
673 
674             num |= 0x4000; /* set F BIT */
675             if (len == 0) {
676                 num |= I596_EOF; /* set EOF BIT */
677             }
678             set_uint16(rbd + 0, num); /* write actual count with flags */
679 
680             /* get next rbd */
681             rbd = get_uint32(rbd + 4);
682             /* printf("Next Receive: rbd is %08x\n", rbd); */
683 
684             if (buffer_size & I596_EOF) /* last entry */
685                 break;
686         }
687 
688         /* Housekeeping, see pg. 18 */
689         next_rfd = get_uint32(rfd_p + 4);
690         set_uint32(next_rfd + 8, rbd);
691 
692         status = STAT_C | STAT_OK | is_broadcast;
693         set_uint16(rfd_p, status);
694 
695         if (command & CMD_SUSP) {  /* suspend after command? */
696             s->rx_status = RX_SUSPENDED;
697             s->scb_status |= SCB_STATUS_RNR; /* RU left active state */
698             break;
699         }
700         if (command & CMD_EOL) /* was it last Frame Descriptor? */
701             break;
702 
703         assert(len == 0);
704     }
705 
706     assert(len == 0);
707 
708     s->scb_status |= SCB_STATUS_FR; /* set "RU finished receiving frame" bit. */
709     update_scb_status(s);
710 
711     /* send IRQ that we received data */
712     qemu_set_irq(s->irq, 1);
713     /* s->send_irq = 1; */
714 
715     if (0) {
716         DBG(printf("Checking:\n"));
717         rfd_p = get_uint32(s->scb + 8); /* get Receive Frame Descriptor */
718         DBG(printf("Next Receive: rfd is %08x\n", rfd_p));
719         rfd_p = get_uint32(rfd_p + 4); /* get Next Receive Frame Descriptor */
720         DBG(printf("Next Receive: rfd is %08x\n", rfd_p));
721         /* get first Receive Buffer Descriptor Address */
722         rbd = get_uint32(rfd_p + 8);
723         DBG(printf("Next Receive: rbd is %08x\n", rbd));
724     }
725 
726     return sz;
727 }
728 
729 
730 const VMStateDescription vmstate_i82596 = {
731     .name = "i82596",
732     .version_id = 1,
733     .minimum_version_id = 1,
734     .fields = (VMStateField[]) {
735         VMSTATE_UINT16(lnkst, I82596State),
736         VMSTATE_TIMER_PTR(flush_queue_timer, I82596State),
737         VMSTATE_END_OF_LIST()
738     }
739 };
740 
741 void i82596_common_init(DeviceState *dev, I82596State *s, NetClientInfo *info)
742 {
743     if (s->conf.macaddr.a[0] == 0) {
744         qemu_macaddr_default_if_unset(&s->conf.macaddr);
745     }
746     s->nic = qemu_new_nic(info, &s->conf, object_get_typename(OBJECT(dev)),
747                 dev->id, s);
748     qemu_format_nic_info_str(qemu_get_queue(s->nic), s->conf.macaddr.a);
749 
750     if (USE_TIMER) {
751         s->flush_queue_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
752                                     i82596_flush_queue_timer, s);
753     }
754     s->lnkst = 0x8000; /* initial link state: up */
755 }
756