xref: /openbmc/qemu/hw/net/dp8393x.c (revision 135b03cb)
1 /*
2  * QEMU NS SONIC DP8393x netcard
3  *
4  * Copyright (c) 2008-2009 Herve Poussineau
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License as
8  * published by the Free Software Foundation; either version 2 of
9  * the License, or (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License along
17  * with this program; if not, see <http://www.gnu.org/licenses/>.
18  */
19 
20 #include "qemu/osdep.h"
21 #include "hw/irq.h"
22 #include "hw/qdev-properties.h"
23 #include "hw/sysbus.h"
24 #include "migration/vmstate.h"
25 #include "net/net.h"
26 #include "qapi/error.h"
27 #include "qemu/module.h"
28 #include "qemu/timer.h"
29 #include <zlib.h>
30 
31 //#define DEBUG_SONIC
32 
33 #define SONIC_PROM_SIZE 0x1000
34 
35 #ifdef DEBUG_SONIC
36 #define DPRINTF(fmt, ...) \
37 do { printf("sonic: " fmt , ##  __VA_ARGS__); } while (0)
38 static const char* reg_names[] = {
39     "CR", "DCR", "RCR", "TCR", "IMR", "ISR", "UTDA", "CTDA",
40     "TPS", "TFC", "TSA0", "TSA1", "TFS", "URDA", "CRDA", "CRBA0",
41     "CRBA1", "RBWC0", "RBWC1", "EOBC", "URRA", "RSA", "REA", "RRP",
42     "RWP", "TRBA0", "TRBA1", "0x1b", "0x1c", "0x1d", "0x1e", "LLFA",
43     "TTDA", "CEP", "CAP2", "CAP1", "CAP0", "CE", "CDP", "CDC",
44     "SR", "WT0", "WT1", "RSC", "CRCT", "FAET", "MPT", "MDT",
45     "0x30", "0x31", "0x32", "0x33", "0x34", "0x35", "0x36", "0x37",
46     "0x38", "0x39", "0x3a", "0x3b", "0x3c", "0x3d", "0x3e", "DCR2" };
47 #else
48 #define DPRINTF(fmt, ...) do {} while (0)
49 #endif
50 
51 #define SONIC_ERROR(fmt, ...) \
52 do { printf("sonic ERROR: %s: " fmt, __func__ , ## __VA_ARGS__); } while (0)
53 
54 #define SONIC_CR     0x00
55 #define SONIC_DCR    0x01
56 #define SONIC_RCR    0x02
57 #define SONIC_TCR    0x03
58 #define SONIC_IMR    0x04
59 #define SONIC_ISR    0x05
60 #define SONIC_UTDA   0x06
61 #define SONIC_CTDA   0x07
62 #define SONIC_TPS    0x08
63 #define SONIC_TFC    0x09
64 #define SONIC_TSA0   0x0a
65 #define SONIC_TSA1   0x0b
66 #define SONIC_TFS    0x0c
67 #define SONIC_URDA   0x0d
68 #define SONIC_CRDA   0x0e
69 #define SONIC_CRBA0  0x0f
70 #define SONIC_CRBA1  0x10
71 #define SONIC_RBWC0  0x11
72 #define SONIC_RBWC1  0x12
73 #define SONIC_EOBC   0x13
74 #define SONIC_URRA   0x14
75 #define SONIC_RSA    0x15
76 #define SONIC_REA    0x16
77 #define SONIC_RRP    0x17
78 #define SONIC_RWP    0x18
79 #define SONIC_TRBA0  0x19
80 #define SONIC_TRBA1  0x1a
81 #define SONIC_LLFA   0x1f
82 #define SONIC_TTDA   0x20
83 #define SONIC_CEP    0x21
84 #define SONIC_CAP2   0x22
85 #define SONIC_CAP1   0x23
86 #define SONIC_CAP0   0x24
87 #define SONIC_CE     0x25
88 #define SONIC_CDP    0x26
89 #define SONIC_CDC    0x27
90 #define SONIC_SR     0x28
91 #define SONIC_WT0    0x29
92 #define SONIC_WT1    0x2a
93 #define SONIC_RSC    0x2b
94 #define SONIC_CRCT   0x2c
95 #define SONIC_FAET   0x2d
96 #define SONIC_MPT    0x2e
97 #define SONIC_MDT    0x2f
98 #define SONIC_DCR2   0x3f
99 
100 #define SONIC_CR_HTX     0x0001
101 #define SONIC_CR_TXP     0x0002
102 #define SONIC_CR_RXDIS   0x0004
103 #define SONIC_CR_RXEN    0x0008
104 #define SONIC_CR_STP     0x0010
105 #define SONIC_CR_ST      0x0020
106 #define SONIC_CR_RST     0x0080
107 #define SONIC_CR_RRRA    0x0100
108 #define SONIC_CR_LCAM    0x0200
109 #define SONIC_CR_MASK    0x03bf
110 
111 #define SONIC_DCR_DW     0x0020
112 #define SONIC_DCR_LBR    0x2000
113 #define SONIC_DCR_EXBUS  0x8000
114 
115 #define SONIC_RCR_PRX    0x0001
116 #define SONIC_RCR_LBK    0x0002
117 #define SONIC_RCR_FAER   0x0004
118 #define SONIC_RCR_CRCR   0x0008
119 #define SONIC_RCR_CRS    0x0020
120 #define SONIC_RCR_LPKT   0x0040
121 #define SONIC_RCR_BC     0x0080
122 #define SONIC_RCR_MC     0x0100
123 #define SONIC_RCR_LB0    0x0200
124 #define SONIC_RCR_LB1    0x0400
125 #define SONIC_RCR_AMC    0x0800
126 #define SONIC_RCR_PRO    0x1000
127 #define SONIC_RCR_BRD    0x2000
128 #define SONIC_RCR_RNT    0x4000
129 
130 #define SONIC_TCR_PTX    0x0001
131 #define SONIC_TCR_BCM    0x0002
132 #define SONIC_TCR_FU     0x0004
133 #define SONIC_TCR_EXC    0x0040
134 #define SONIC_TCR_CRSL   0x0080
135 #define SONIC_TCR_NCRS   0x0100
136 #define SONIC_TCR_EXD    0x0400
137 #define SONIC_TCR_CRCI   0x2000
138 #define SONIC_TCR_PINT   0x8000
139 
140 #define SONIC_ISR_RBE    0x0020
141 #define SONIC_ISR_RDE    0x0040
142 #define SONIC_ISR_TC     0x0080
143 #define SONIC_ISR_TXDN   0x0200
144 #define SONIC_ISR_PKTRX  0x0400
145 #define SONIC_ISR_PINT   0x0800
146 #define SONIC_ISR_LCD    0x1000
147 
148 #define TYPE_DP8393X "dp8393x"
149 #define DP8393X(obj) OBJECT_CHECK(dp8393xState, (obj), TYPE_DP8393X)
150 
151 typedef struct dp8393xState {
152     SysBusDevice parent_obj;
153 
154     /* Hardware */
155     uint8_t it_shift;
156     qemu_irq irq;
157 #ifdef DEBUG_SONIC
158     int irq_level;
159 #endif
160     QEMUTimer *watchdog;
161     int64_t wt_last_update;
162     NICConf conf;
163     NICState *nic;
164     MemoryRegion mmio;
165     MemoryRegion prom;
166 
167     /* Registers */
168     uint8_t cam[16][6];
169     uint16_t regs[0x40];
170 
171     /* Temporaries */
172     uint8_t tx_buffer[0x10000];
173     int loopback_packet;
174 
175     /* Memory access */
176     void *dma_mr;
177     AddressSpace as;
178 } dp8393xState;
179 
180 /* Accessor functions for values which are formed by
181  * concatenating two 16 bit device registers. By putting these
182  * in their own functions with a uint32_t return type we avoid the
183  * pitfall of implicit sign extension where ((x << 16) | y) is a
184  * signed 32 bit integer that might get sign-extended to a 64 bit integer.
185  */
186 static uint32_t dp8393x_cdp(dp8393xState *s)
187 {
188     return (s->regs[SONIC_URRA] << 16) | s->regs[SONIC_CDP];
189 }
190 
191 static uint32_t dp8393x_crba(dp8393xState *s)
192 {
193     return (s->regs[SONIC_CRBA1] << 16) | s->regs[SONIC_CRBA0];
194 }
195 
196 static uint32_t dp8393x_crda(dp8393xState *s)
197 {
198     return (s->regs[SONIC_URDA] << 16) | s->regs[SONIC_CRDA];
199 }
200 
201 static uint32_t dp8393x_rbwc(dp8393xState *s)
202 {
203     return (s->regs[SONIC_RBWC1] << 16) | s->regs[SONIC_RBWC0];
204 }
205 
206 static uint32_t dp8393x_rrp(dp8393xState *s)
207 {
208     return (s->regs[SONIC_URRA] << 16) | s->regs[SONIC_RRP];
209 }
210 
211 static uint32_t dp8393x_tsa(dp8393xState *s)
212 {
213     return (s->regs[SONIC_TSA1] << 16) | s->regs[SONIC_TSA0];
214 }
215 
216 static uint32_t dp8393x_ttda(dp8393xState *s)
217 {
218     return (s->regs[SONIC_UTDA] << 16) | s->regs[SONIC_TTDA];
219 }
220 
221 static uint32_t dp8393x_wt(dp8393xState *s)
222 {
223     return s->regs[SONIC_WT1] << 16 | s->regs[SONIC_WT0];
224 }
225 
226 static void dp8393x_update_irq(dp8393xState *s)
227 {
228     int level = (s->regs[SONIC_IMR] & s->regs[SONIC_ISR]) ? 1 : 0;
229 
230 #ifdef DEBUG_SONIC
231     if (level != s->irq_level) {
232         s->irq_level = level;
233         if (level) {
234             DPRINTF("raise irq, isr is 0x%04x\n", s->regs[SONIC_ISR]);
235         } else {
236             DPRINTF("lower irq\n");
237         }
238     }
239 #endif
240 
241     qemu_set_irq(s->irq, level);
242 }
243 
244 static void dp8393x_do_load_cam(dp8393xState *s)
245 {
246     uint16_t data[8];
247     int width, size;
248     uint16_t index = 0;
249 
250     width = (s->regs[SONIC_DCR] & SONIC_DCR_DW) ? 2 : 1;
251     size = sizeof(uint16_t) * 4 * width;
252 
253     while (s->regs[SONIC_CDC] & 0x1f) {
254         /* Fill current entry */
255         address_space_rw(&s->as, dp8393x_cdp(s),
256             MEMTXATTRS_UNSPECIFIED, (uint8_t *)data, size, 0);
257         s->cam[index][0] = data[1 * width] & 0xff;
258         s->cam[index][1] = data[1 * width] >> 8;
259         s->cam[index][2] = data[2 * width] & 0xff;
260         s->cam[index][3] = data[2 * width] >> 8;
261         s->cam[index][4] = data[3 * width] & 0xff;
262         s->cam[index][5] = data[3 * width] >> 8;
263         DPRINTF("load cam[%d] with %02x%02x%02x%02x%02x%02x\n", index,
264             s->cam[index][0], s->cam[index][1], s->cam[index][2],
265             s->cam[index][3], s->cam[index][4], s->cam[index][5]);
266         /* Move to next entry */
267         s->regs[SONIC_CDC]--;
268         s->regs[SONIC_CDP] += size;
269         index++;
270     }
271 
272     /* Read CAM enable */
273     address_space_rw(&s->as, dp8393x_cdp(s),
274         MEMTXATTRS_UNSPECIFIED, (uint8_t *)data, size, 0);
275     s->regs[SONIC_CE] = data[0 * width];
276     DPRINTF("load cam done. cam enable mask 0x%04x\n", s->regs[SONIC_CE]);
277 
278     /* Done */
279     s->regs[SONIC_CR] &= ~SONIC_CR_LCAM;
280     s->regs[SONIC_ISR] |= SONIC_ISR_LCD;
281     dp8393x_update_irq(s);
282 }
283 
284 static void dp8393x_do_read_rra(dp8393xState *s)
285 {
286     uint16_t data[8];
287     int width, size;
288 
289     /* Read memory */
290     width = (s->regs[SONIC_DCR] & SONIC_DCR_DW) ? 2 : 1;
291     size = sizeof(uint16_t) * 4 * width;
292     address_space_rw(&s->as, dp8393x_rrp(s),
293         MEMTXATTRS_UNSPECIFIED, (uint8_t *)data, size, 0);
294 
295     /* Update SONIC registers */
296     s->regs[SONIC_CRBA0] = data[0 * width];
297     s->regs[SONIC_CRBA1] = data[1 * width];
298     s->regs[SONIC_RBWC0] = data[2 * width];
299     s->regs[SONIC_RBWC1] = data[3 * width];
300     DPRINTF("CRBA0/1: 0x%04x/0x%04x, RBWC0/1: 0x%04x/0x%04x\n",
301         s->regs[SONIC_CRBA0], s->regs[SONIC_CRBA1],
302         s->regs[SONIC_RBWC0], s->regs[SONIC_RBWC1]);
303 
304     /* Go to next entry */
305     s->regs[SONIC_RRP] += size;
306 
307     /* Handle wrap */
308     if (s->regs[SONIC_RRP] == s->regs[SONIC_REA]) {
309         s->regs[SONIC_RRP] = s->regs[SONIC_RSA];
310     }
311 
312     /* Check resource exhaustion */
313     if (s->regs[SONIC_RRP] == s->regs[SONIC_RWP])
314     {
315         s->regs[SONIC_ISR] |= SONIC_ISR_RBE;
316         dp8393x_update_irq(s);
317     }
318 
319     /* Done */
320     s->regs[SONIC_CR] &= ~SONIC_CR_RRRA;
321 }
322 
323 static void dp8393x_do_software_reset(dp8393xState *s)
324 {
325     timer_del(s->watchdog);
326 
327     s->regs[SONIC_CR] &= ~(SONIC_CR_LCAM | SONIC_CR_RRRA | SONIC_CR_TXP | SONIC_CR_HTX);
328     s->regs[SONIC_CR] |= SONIC_CR_RST | SONIC_CR_RXDIS;
329 }
330 
331 static void dp8393x_set_next_tick(dp8393xState *s)
332 {
333     uint32_t ticks;
334     int64_t delay;
335 
336     if (s->regs[SONIC_CR] & SONIC_CR_STP) {
337         timer_del(s->watchdog);
338         return;
339     }
340 
341     ticks = dp8393x_wt(s);
342     s->wt_last_update = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
343     delay = NANOSECONDS_PER_SECOND * ticks / 5000000;
344     timer_mod(s->watchdog, s->wt_last_update + delay);
345 }
346 
347 static void dp8393x_update_wt_regs(dp8393xState *s)
348 {
349     int64_t elapsed;
350     uint32_t val;
351 
352     if (s->regs[SONIC_CR] & SONIC_CR_STP) {
353         timer_del(s->watchdog);
354         return;
355     }
356 
357     elapsed = s->wt_last_update - qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
358     val = dp8393x_wt(s);
359     val -= elapsed / 5000000;
360     s->regs[SONIC_WT1] = (val >> 16) & 0xffff;
361     s->regs[SONIC_WT0] = (val >> 0)  & 0xffff;
362     dp8393x_set_next_tick(s);
363 
364 }
365 
366 static void dp8393x_do_start_timer(dp8393xState *s)
367 {
368     s->regs[SONIC_CR] &= ~SONIC_CR_STP;
369     dp8393x_set_next_tick(s);
370 }
371 
372 static void dp8393x_do_stop_timer(dp8393xState *s)
373 {
374     s->regs[SONIC_CR] &= ~SONIC_CR_ST;
375     dp8393x_update_wt_regs(s);
376 }
377 
378 static int dp8393x_can_receive(NetClientState *nc);
379 
380 static void dp8393x_do_receiver_enable(dp8393xState *s)
381 {
382     s->regs[SONIC_CR] &= ~SONIC_CR_RXDIS;
383     if (dp8393x_can_receive(s->nic->ncs)) {
384         qemu_flush_queued_packets(qemu_get_queue(s->nic));
385     }
386 }
387 
388 static void dp8393x_do_receiver_disable(dp8393xState *s)
389 {
390     s->regs[SONIC_CR] &= ~SONIC_CR_RXEN;
391 }
392 
393 static void dp8393x_do_transmit_packets(dp8393xState *s)
394 {
395     NetClientState *nc = qemu_get_queue(s->nic);
396     uint16_t data[12];
397     int width, size;
398     int tx_len, len;
399     uint16_t i;
400 
401     width = (s->regs[SONIC_DCR] & SONIC_DCR_DW) ? 2 : 1;
402 
403     while (1) {
404         /* Read memory */
405         size = sizeof(uint16_t) * 6 * width;
406         s->regs[SONIC_TTDA] = s->regs[SONIC_CTDA];
407         DPRINTF("Transmit packet at %08x\n", dp8393x_ttda(s));
408         address_space_rw(&s->as,
409             dp8393x_ttda(s) + sizeof(uint16_t) * width,
410             MEMTXATTRS_UNSPECIFIED, (uint8_t *)data, size, 0);
411         tx_len = 0;
412 
413         /* Update registers */
414         s->regs[SONIC_TCR] = data[0 * width] & 0xf000;
415         s->regs[SONIC_TPS] = data[1 * width];
416         s->regs[SONIC_TFC] = data[2 * width];
417         s->regs[SONIC_TSA0] = data[3 * width];
418         s->regs[SONIC_TSA1] = data[4 * width];
419         s->regs[SONIC_TFS] = data[5 * width];
420 
421         /* Handle programmable interrupt */
422         if (s->regs[SONIC_TCR] & SONIC_TCR_PINT) {
423             s->regs[SONIC_ISR] |= SONIC_ISR_PINT;
424         } else {
425             s->regs[SONIC_ISR] &= ~SONIC_ISR_PINT;
426         }
427 
428         for (i = 0; i < s->regs[SONIC_TFC]; ) {
429             /* Append fragment */
430             len = s->regs[SONIC_TFS];
431             if (tx_len + len > sizeof(s->tx_buffer)) {
432                 len = sizeof(s->tx_buffer) - tx_len;
433             }
434             address_space_rw(&s->as, dp8393x_tsa(s),
435                 MEMTXATTRS_UNSPECIFIED, &s->tx_buffer[tx_len], len, 0);
436             tx_len += len;
437 
438             i++;
439             if (i != s->regs[SONIC_TFC]) {
440                 /* Read next fragment details */
441                 size = sizeof(uint16_t) * 3 * width;
442                 address_space_rw(&s->as,
443                     dp8393x_ttda(s) + sizeof(uint16_t) * (4 + 3 * i) * width,
444                     MEMTXATTRS_UNSPECIFIED, (uint8_t *)data, size, 0);
445                 s->regs[SONIC_TSA0] = data[0 * width];
446                 s->regs[SONIC_TSA1] = data[1 * width];
447                 s->regs[SONIC_TFS] = data[2 * width];
448             }
449         }
450 
451         /* Handle Ethernet checksum */
452         if (!(s->regs[SONIC_TCR] & SONIC_TCR_CRCI)) {
453             /* Don't append FCS there, to look like slirp packets
454              * which don't have one */
455         } else {
456             /* Remove existing FCS */
457             tx_len -= 4;
458         }
459 
460         if (s->regs[SONIC_RCR] & (SONIC_RCR_LB1 | SONIC_RCR_LB0)) {
461             /* Loopback */
462             s->regs[SONIC_TCR] |= SONIC_TCR_CRSL;
463             if (nc->info->can_receive(nc)) {
464                 s->loopback_packet = 1;
465                 nc->info->receive(nc, s->tx_buffer, tx_len);
466             }
467         } else {
468             /* Transmit packet */
469             qemu_send_packet(nc, s->tx_buffer, tx_len);
470         }
471         s->regs[SONIC_TCR] |= SONIC_TCR_PTX;
472 
473         /* Write status */
474         data[0 * width] = s->regs[SONIC_TCR] & 0x0fff; /* status */
475         size = sizeof(uint16_t) * width;
476         address_space_rw(&s->as,
477             dp8393x_ttda(s),
478             MEMTXATTRS_UNSPECIFIED, (uint8_t *)data, size, 1);
479 
480         if (!(s->regs[SONIC_CR] & SONIC_CR_HTX)) {
481             /* Read footer of packet */
482             size = sizeof(uint16_t) * width;
483             address_space_rw(&s->as,
484                 dp8393x_ttda(s) +
485                              sizeof(uint16_t) *
486                              (4 + 3 * s->regs[SONIC_TFC]) * width,
487                 MEMTXATTRS_UNSPECIFIED, (uint8_t *)data, size, 0);
488             s->regs[SONIC_CTDA] = data[0 * width] & ~0x1;
489             if (data[0 * width] & 0x1) {
490                 /* EOL detected */
491                 break;
492             }
493         }
494     }
495 
496     /* Done */
497     s->regs[SONIC_CR] &= ~SONIC_CR_TXP;
498     s->regs[SONIC_ISR] |= SONIC_ISR_TXDN;
499     dp8393x_update_irq(s);
500 }
501 
502 static void dp8393x_do_halt_transmission(dp8393xState *s)
503 {
504     /* Nothing to do */
505 }
506 
507 static void dp8393x_do_command(dp8393xState *s, uint16_t command)
508 {
509     if ((s->regs[SONIC_CR] & SONIC_CR_RST) && !(command & SONIC_CR_RST)) {
510         s->regs[SONIC_CR] &= ~SONIC_CR_RST;
511         return;
512     }
513 
514     s->regs[SONIC_CR] |= (command & SONIC_CR_MASK);
515 
516     if (command & SONIC_CR_HTX)
517         dp8393x_do_halt_transmission(s);
518     if (command & SONIC_CR_TXP)
519         dp8393x_do_transmit_packets(s);
520     if (command & SONIC_CR_RXDIS)
521         dp8393x_do_receiver_disable(s);
522     if (command & SONIC_CR_RXEN)
523         dp8393x_do_receiver_enable(s);
524     if (command & SONIC_CR_STP)
525         dp8393x_do_stop_timer(s);
526     if (command & SONIC_CR_ST)
527         dp8393x_do_start_timer(s);
528     if (command & SONIC_CR_RST)
529         dp8393x_do_software_reset(s);
530     if (command & SONIC_CR_RRRA)
531         dp8393x_do_read_rra(s);
532     if (command & SONIC_CR_LCAM)
533         dp8393x_do_load_cam(s);
534 }
535 
536 static uint64_t dp8393x_read(void *opaque, hwaddr addr, unsigned int size)
537 {
538     dp8393xState *s = opaque;
539     int reg = addr >> s->it_shift;
540     uint16_t val = 0;
541 
542     switch (reg) {
543         /* Update data before reading it */
544         case SONIC_WT0:
545         case SONIC_WT1:
546             dp8393x_update_wt_regs(s);
547             val = s->regs[reg];
548             break;
549         /* Accept read to some registers only when in reset mode */
550         case SONIC_CAP2:
551         case SONIC_CAP1:
552         case SONIC_CAP0:
553             if (s->regs[SONIC_CR] & SONIC_CR_RST) {
554                 val = s->cam[s->regs[SONIC_CEP] & 0xf][2* (SONIC_CAP0 - reg) + 1] << 8;
555                 val |= s->cam[s->regs[SONIC_CEP] & 0xf][2* (SONIC_CAP0 - reg)];
556             }
557             break;
558         /* All other registers have no special contrainst */
559         default:
560             val = s->regs[reg];
561     }
562 
563     DPRINTF("read 0x%04x from reg %s\n", val, reg_names[reg]);
564 
565     return val;
566 }
567 
568 static void dp8393x_write(void *opaque, hwaddr addr, uint64_t data,
569                           unsigned int size)
570 {
571     dp8393xState *s = opaque;
572     int reg = addr >> s->it_shift;
573 
574     DPRINTF("write 0x%04x to reg %s\n", (uint16_t)data, reg_names[reg]);
575 
576     switch (reg) {
577         /* Command register */
578         case SONIC_CR:
579             dp8393x_do_command(s, data);
580             break;
581         /* Prevent write to read-only registers */
582         case SONIC_CAP2:
583         case SONIC_CAP1:
584         case SONIC_CAP0:
585         case SONIC_SR:
586         case SONIC_MDT:
587             DPRINTF("writing to reg %d invalid\n", reg);
588             break;
589         /* Accept write to some registers only when in reset mode */
590         case SONIC_DCR:
591             if (s->regs[SONIC_CR] & SONIC_CR_RST) {
592                 s->regs[reg] = data & 0xbfff;
593             } else {
594                 DPRINTF("writing to DCR invalid\n");
595             }
596             break;
597         case SONIC_DCR2:
598             if (s->regs[SONIC_CR] & SONIC_CR_RST) {
599                 s->regs[reg] = data & 0xf017;
600             } else {
601                 DPRINTF("writing to DCR2 invalid\n");
602             }
603             break;
604         /* 12 lower bytes are Read Only */
605         case SONIC_TCR:
606             s->regs[reg] = data & 0xf000;
607             break;
608         /* 9 lower bytes are Read Only */
609         case SONIC_RCR:
610             s->regs[reg] = data & 0xffe0;
611             break;
612         /* Ignore most significant bit */
613         case SONIC_IMR:
614             s->regs[reg] = data & 0x7fff;
615             dp8393x_update_irq(s);
616             break;
617         /* Clear bits by writing 1 to them */
618         case SONIC_ISR:
619             data &= s->regs[reg];
620             s->regs[reg] &= ~data;
621             if (data & SONIC_ISR_RBE) {
622                 dp8393x_do_read_rra(s);
623             }
624             dp8393x_update_irq(s);
625             if (dp8393x_can_receive(s->nic->ncs)) {
626                 qemu_flush_queued_packets(qemu_get_queue(s->nic));
627             }
628             break;
629         /* Ignore least significant bit */
630         case SONIC_RSA:
631         case SONIC_REA:
632         case SONIC_RRP:
633         case SONIC_RWP:
634             s->regs[reg] = data & 0xfffe;
635             break;
636         /* Invert written value for some registers */
637         case SONIC_CRCT:
638         case SONIC_FAET:
639         case SONIC_MPT:
640             s->regs[reg] = data ^ 0xffff;
641             break;
642         /* All other registers have no special contrainst */
643         default:
644             s->regs[reg] = data;
645     }
646 
647     if (reg == SONIC_WT0 || reg == SONIC_WT1) {
648         dp8393x_set_next_tick(s);
649     }
650 }
651 
652 static const MemoryRegionOps dp8393x_ops = {
653     .read = dp8393x_read,
654     .write = dp8393x_write,
655     .impl.min_access_size = 2,
656     .impl.max_access_size = 2,
657     .endianness = DEVICE_NATIVE_ENDIAN,
658 };
659 
660 static void dp8393x_watchdog(void *opaque)
661 {
662     dp8393xState *s = opaque;
663 
664     if (s->regs[SONIC_CR] & SONIC_CR_STP) {
665         return;
666     }
667 
668     s->regs[SONIC_WT1] = 0xffff;
669     s->regs[SONIC_WT0] = 0xffff;
670     dp8393x_set_next_tick(s);
671 
672     /* Signal underflow */
673     s->regs[SONIC_ISR] |= SONIC_ISR_TC;
674     dp8393x_update_irq(s);
675 }
676 
677 static int dp8393x_can_receive(NetClientState *nc)
678 {
679     dp8393xState *s = qemu_get_nic_opaque(nc);
680 
681     if (!(s->regs[SONIC_CR] & SONIC_CR_RXEN))
682         return 0;
683     if (s->regs[SONIC_ISR] & SONIC_ISR_RBE)
684         return 0;
685     return 1;
686 }
687 
688 static int dp8393x_receive_filter(dp8393xState *s, const uint8_t * buf,
689                                   int size)
690 {
691     static const uint8_t bcast[] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
692     int i;
693 
694     /* Check promiscuous mode */
695     if ((s->regs[SONIC_RCR] & SONIC_RCR_PRO) && (buf[0] & 1) == 0) {
696         return 0;
697     }
698 
699     /* Check multicast packets */
700     if ((s->regs[SONIC_RCR] & SONIC_RCR_AMC) && (buf[0] & 1) == 1) {
701         return SONIC_RCR_MC;
702     }
703 
704     /* Check broadcast */
705     if ((s->regs[SONIC_RCR] & SONIC_RCR_BRD) && !memcmp(buf, bcast, sizeof(bcast))) {
706         return SONIC_RCR_BC;
707     }
708 
709     /* Check CAM */
710     for (i = 0; i < 16; i++) {
711         if (s->regs[SONIC_CE] & (1 << i)) {
712              /* Entry enabled */
713              if (!memcmp(buf, s->cam[i], sizeof(s->cam[i]))) {
714                  return 0;
715              }
716         }
717     }
718 
719     return -1;
720 }
721 
722 static ssize_t dp8393x_receive(NetClientState *nc, const uint8_t * buf,
723                                size_t size)
724 {
725     dp8393xState *s = qemu_get_nic_opaque(nc);
726     uint16_t data[10];
727     int packet_type;
728     uint32_t available, address;
729     int width, rx_len = size;
730     uint32_t checksum;
731 
732     width = (s->regs[SONIC_DCR] & SONIC_DCR_DW) ? 2 : 1;
733 
734     s->regs[SONIC_RCR] &= ~(SONIC_RCR_PRX | SONIC_RCR_LBK | SONIC_RCR_FAER |
735         SONIC_RCR_CRCR | SONIC_RCR_LPKT | SONIC_RCR_BC | SONIC_RCR_MC);
736 
737     packet_type = dp8393x_receive_filter(s, buf, size);
738     if (packet_type < 0) {
739         DPRINTF("packet not for netcard\n");
740         return -1;
741     }
742 
743     /* XXX: Check byte ordering */
744 
745     /* Check for EOL */
746     if (s->regs[SONIC_LLFA] & 0x1) {
747         /* Are we still in resource exhaustion? */
748         size = sizeof(uint16_t) * 1 * width;
749         address = dp8393x_crda(s) + sizeof(uint16_t) * 5 * width;
750         address_space_rw(&s->as, address, MEMTXATTRS_UNSPECIFIED,
751                          (uint8_t *)data, size, 0);
752         if (data[0 * width] & 0x1) {
753             /* Still EOL ; stop reception */
754             return -1;
755         } else {
756             s->regs[SONIC_CRDA] = s->regs[SONIC_LLFA];
757         }
758     }
759 
760     /* Save current position */
761     s->regs[SONIC_TRBA1] = s->regs[SONIC_CRBA1];
762     s->regs[SONIC_TRBA0] = s->regs[SONIC_CRBA0];
763 
764     /* Calculate the ethernet checksum */
765     checksum = cpu_to_le32(crc32(0, buf, rx_len));
766 
767     /* Put packet into RBA */
768     DPRINTF("Receive packet at %08x\n", dp8393x_crba(s));
769     address = dp8393x_crba(s);
770     address_space_rw(&s->as, address,
771         MEMTXATTRS_UNSPECIFIED, (uint8_t *)buf, rx_len, 1);
772     address += rx_len;
773     address_space_rw(&s->as, address,
774         MEMTXATTRS_UNSPECIFIED, (uint8_t *)&checksum, 4, 1);
775     rx_len += 4;
776     s->regs[SONIC_CRBA1] = address >> 16;
777     s->regs[SONIC_CRBA0] = address & 0xffff;
778     available = dp8393x_rbwc(s);
779     available -= rx_len / 2;
780     s->regs[SONIC_RBWC1] = available >> 16;
781     s->regs[SONIC_RBWC0] = available & 0xffff;
782 
783     /* Update status */
784     if (dp8393x_rbwc(s) < s->regs[SONIC_EOBC]) {
785         s->regs[SONIC_RCR] |= SONIC_RCR_LPKT;
786     }
787     s->regs[SONIC_RCR] |= packet_type;
788     s->regs[SONIC_RCR] |= SONIC_RCR_PRX;
789     if (s->loopback_packet) {
790         s->regs[SONIC_RCR] |= SONIC_RCR_LBK;
791         s->loopback_packet = 0;
792     }
793 
794     /* Write status to memory */
795     DPRINTF("Write status at %08x\n", dp8393x_crda(s));
796     data[0 * width] = s->regs[SONIC_RCR]; /* status */
797     data[1 * width] = rx_len; /* byte count */
798     data[2 * width] = s->regs[SONIC_TRBA0]; /* pkt_ptr0 */
799     data[3 * width] = s->regs[SONIC_TRBA1]; /* pkt_ptr1 */
800     data[4 * width] = s->regs[SONIC_RSC]; /* seq_no */
801     size = sizeof(uint16_t) * 5 * width;
802     address_space_rw(&s->as, dp8393x_crda(s),
803         MEMTXATTRS_UNSPECIFIED, (uint8_t *)data, size, 1);
804 
805     /* Move to next descriptor */
806     size = sizeof(uint16_t) * width;
807     address_space_rw(&s->as, dp8393x_crda(s) + sizeof(uint16_t) * 5 * width,
808         MEMTXATTRS_UNSPECIFIED, (uint8_t *)data, size, 0);
809     s->regs[SONIC_LLFA] = data[0 * width];
810     if (s->regs[SONIC_LLFA] & 0x1) {
811         /* EOL detected */
812         s->regs[SONIC_ISR] |= SONIC_ISR_RDE;
813     } else {
814         data[0 * width] = 0; /* in_use */
815         address_space_rw(&s->as, dp8393x_crda(s) + sizeof(uint16_t) * 6 * width,
816             MEMTXATTRS_UNSPECIFIED, (uint8_t *)data, sizeof(uint16_t), 1);
817         s->regs[SONIC_CRDA] = s->regs[SONIC_LLFA];
818         s->regs[SONIC_ISR] |= SONIC_ISR_PKTRX;
819         s->regs[SONIC_RSC] = (s->regs[SONIC_RSC] & 0xff00) | (((s->regs[SONIC_RSC] & 0x00ff) + 1) & 0x00ff);
820 
821         if (s->regs[SONIC_RCR] & SONIC_RCR_LPKT) {
822             /* Read next RRA */
823             dp8393x_do_read_rra(s);
824         }
825     }
826 
827     /* Done */
828     dp8393x_update_irq(s);
829 
830     return size;
831 }
832 
833 static void dp8393x_reset(DeviceState *dev)
834 {
835     dp8393xState *s = DP8393X(dev);
836     timer_del(s->watchdog);
837 
838     memset(s->regs, 0, sizeof(s->regs));
839     s->regs[SONIC_CR] = SONIC_CR_RST | SONIC_CR_STP | SONIC_CR_RXDIS;
840     s->regs[SONIC_DCR] &= ~(SONIC_DCR_EXBUS | SONIC_DCR_LBR);
841     s->regs[SONIC_RCR] &= ~(SONIC_RCR_LB0 | SONIC_RCR_LB1 | SONIC_RCR_BRD | SONIC_RCR_RNT);
842     s->regs[SONIC_TCR] |= SONIC_TCR_NCRS | SONIC_TCR_PTX;
843     s->regs[SONIC_TCR] &= ~SONIC_TCR_BCM;
844     s->regs[SONIC_IMR] = 0;
845     s->regs[SONIC_ISR] = 0;
846     s->regs[SONIC_DCR2] = 0;
847     s->regs[SONIC_EOBC] = 0x02F8;
848     s->regs[SONIC_RSC] = 0;
849     s->regs[SONIC_CE] = 0;
850     s->regs[SONIC_RSC] = 0;
851 
852     /* Network cable is connected */
853     s->regs[SONIC_RCR] |= SONIC_RCR_CRS;
854 
855     dp8393x_update_irq(s);
856 }
857 
858 static NetClientInfo net_dp83932_info = {
859     .type = NET_CLIENT_DRIVER_NIC,
860     .size = sizeof(NICState),
861     .can_receive = dp8393x_can_receive,
862     .receive = dp8393x_receive,
863 };
864 
865 static void dp8393x_instance_init(Object *obj)
866 {
867     SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
868     dp8393xState *s = DP8393X(obj);
869 
870     sysbus_init_mmio(sbd, &s->mmio);
871     sysbus_init_mmio(sbd, &s->prom);
872     sysbus_init_irq(sbd, &s->irq);
873 }
874 
875 static void dp8393x_realize(DeviceState *dev, Error **errp)
876 {
877     dp8393xState *s = DP8393X(dev);
878     int i, checksum;
879     uint8_t *prom;
880     Error *local_err = NULL;
881 
882     address_space_init(&s->as, s->dma_mr, "dp8393x");
883     memory_region_init_io(&s->mmio, OBJECT(dev), &dp8393x_ops, s,
884                           "dp8393x-regs", 0x40 << s->it_shift);
885 
886     s->nic = qemu_new_nic(&net_dp83932_info, &s->conf,
887                           object_get_typename(OBJECT(dev)), dev->id, s);
888     qemu_format_nic_info_str(qemu_get_queue(s->nic), s->conf.macaddr.a);
889 
890     s->watchdog = timer_new_ns(QEMU_CLOCK_VIRTUAL, dp8393x_watchdog, s);
891     s->regs[SONIC_SR] = 0x0004; /* only revision recognized by Linux */
892 
893     memory_region_init_ram(&s->prom, OBJECT(dev),
894                            "dp8393x-prom", SONIC_PROM_SIZE, &local_err);
895     if (local_err) {
896         error_propagate(errp, local_err);
897         return;
898     }
899     memory_region_set_readonly(&s->prom, true);
900     prom = memory_region_get_ram_ptr(&s->prom);
901     checksum = 0;
902     for (i = 0; i < 6; i++) {
903         prom[i] = s->conf.macaddr.a[i];
904         checksum += prom[i];
905         if (checksum > 0xff) {
906             checksum = (checksum + 1) & 0xff;
907         }
908     }
909     prom[7] = 0xff - checksum;
910 }
911 
912 static const VMStateDescription vmstate_dp8393x = {
913     .name = "dp8393x",
914     .version_id = 0,
915     .minimum_version_id = 0,
916     .fields = (VMStateField []) {
917         VMSTATE_BUFFER_UNSAFE(cam, dp8393xState, 0, 16 * 6),
918         VMSTATE_UINT16_ARRAY(regs, dp8393xState, 0x40),
919         VMSTATE_END_OF_LIST()
920     }
921 };
922 
923 static Property dp8393x_properties[] = {
924     DEFINE_NIC_PROPERTIES(dp8393xState, conf),
925     DEFINE_PROP_PTR("dma_mr", dp8393xState, dma_mr),
926     DEFINE_PROP_UINT8("it_shift", dp8393xState, it_shift, 0),
927     DEFINE_PROP_END_OF_LIST(),
928 };
929 
930 static void dp8393x_class_init(ObjectClass *klass, void *data)
931 {
932     DeviceClass *dc = DEVICE_CLASS(klass);
933 
934     set_bit(DEVICE_CATEGORY_NETWORK, dc->categories);
935     dc->realize = dp8393x_realize;
936     dc->reset = dp8393x_reset;
937     dc->vmsd = &vmstate_dp8393x;
938     dc->props = dp8393x_properties;
939     /* Reason: dma_mr property can't be set */
940     dc->user_creatable = false;
941 }
942 
943 static const TypeInfo dp8393x_info = {
944     .name          = TYPE_DP8393X,
945     .parent        = TYPE_SYS_BUS_DEVICE,
946     .instance_size = sizeof(dp8393xState),
947     .instance_init = dp8393x_instance_init,
948     .class_init    = dp8393x_class_init,
949 };
950 
951 static void dp8393x_register_types(void)
952 {
953     type_register_static(&dp8393x_info);
954 }
955 
956 type_init(dp8393x_register_types)
957