xref: /openbmc/qemu/hw/net/cadence_gem.c (revision 2e142114)
1 /*
2  * QEMU Xilinx GEM emulation
3  *
4  * Copyright (c) 2011 Xilinx, Inc.
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a copy
7  * of this software and associated documentation files (the "Software"), to deal
8  * in the Software without restriction, including without limitation the rights
9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10  * copies of the Software, and to permit persons to whom the Software is
11  * furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice shall be included in
14  * all copies or substantial portions of the Software.
15  *
16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22  * THE SOFTWARE.
23  */
24 
25 #include <zlib.h> /* For crc32 */
26 
27 #include "hw/sysbus.h"
28 #include "net/net.h"
29 #include "net/checksum.h"
30 
31 #ifdef CADENCE_GEM_ERR_DEBUG
32 #define DB_PRINT(...) do { \
33     fprintf(stderr,  ": %s: ", __func__); \
34     fprintf(stderr, ## __VA_ARGS__); \
35     } while (0);
36 #else
37     #define DB_PRINT(...)
38 #endif
39 
40 #define GEM_NWCTRL        (0x00000000/4) /* Network Control reg */
41 #define GEM_NWCFG         (0x00000004/4) /* Network Config reg */
42 #define GEM_NWSTATUS      (0x00000008/4) /* Network Status reg */
43 #define GEM_USERIO        (0x0000000C/4) /* User IO reg */
44 #define GEM_DMACFG        (0x00000010/4) /* DMA Control reg */
45 #define GEM_TXSTATUS      (0x00000014/4) /* TX Status reg */
46 #define GEM_RXQBASE       (0x00000018/4) /* RX Q Base address reg */
47 #define GEM_TXQBASE       (0x0000001C/4) /* TX Q Base address reg */
48 #define GEM_RXSTATUS      (0x00000020/4) /* RX Status reg */
49 #define GEM_ISR           (0x00000024/4) /* Interrupt Status reg */
50 #define GEM_IER           (0x00000028/4) /* Interrupt Enable reg */
51 #define GEM_IDR           (0x0000002C/4) /* Interrupt Disable reg */
52 #define GEM_IMR           (0x00000030/4) /* Interrupt Mask reg */
53 #define GEM_PHYMNTNC      (0x00000034/4) /* Phy Maintaince reg */
54 #define GEM_RXPAUSE       (0x00000038/4) /* RX Pause Time reg */
55 #define GEM_TXPAUSE       (0x0000003C/4) /* TX Pause Time reg */
56 #define GEM_TXPARTIALSF   (0x00000040/4) /* TX Partial Store and Forward */
57 #define GEM_RXPARTIALSF   (0x00000044/4) /* RX Partial Store and Forward */
58 #define GEM_HASHLO        (0x00000080/4) /* Hash Low address reg */
59 #define GEM_HASHHI        (0x00000084/4) /* Hash High address reg */
60 #define GEM_SPADDR1LO     (0x00000088/4) /* Specific addr 1 low reg */
61 #define GEM_SPADDR1HI     (0x0000008C/4) /* Specific addr 1 high reg */
62 #define GEM_SPADDR2LO     (0x00000090/4) /* Specific addr 2 low reg */
63 #define GEM_SPADDR2HI     (0x00000094/4) /* Specific addr 2 high reg */
64 #define GEM_SPADDR3LO     (0x00000098/4) /* Specific addr 3 low reg */
65 #define GEM_SPADDR3HI     (0x0000009C/4) /* Specific addr 3 high reg */
66 #define GEM_SPADDR4LO     (0x000000A0/4) /* Specific addr 4 low reg */
67 #define GEM_SPADDR4HI     (0x000000A4/4) /* Specific addr 4 high reg */
68 #define GEM_TIDMATCH1     (0x000000A8/4) /* Type ID1 Match reg */
69 #define GEM_TIDMATCH2     (0x000000AC/4) /* Type ID2 Match reg */
70 #define GEM_TIDMATCH3     (0x000000B0/4) /* Type ID3 Match reg */
71 #define GEM_TIDMATCH4     (0x000000B4/4) /* Type ID4 Match reg */
72 #define GEM_WOLAN         (0x000000B8/4) /* Wake on LAN reg */
73 #define GEM_IPGSTRETCH    (0x000000BC/4) /* IPG Stretch reg */
74 #define GEM_SVLAN         (0x000000C0/4) /* Stacked VLAN reg */
75 #define GEM_MODID         (0x000000FC/4) /* Module ID reg */
76 #define GEM_OCTTXLO       (0x00000100/4) /* Octects transmitted Low reg */
77 #define GEM_OCTTXHI       (0x00000104/4) /* Octects transmitted High reg */
78 #define GEM_TXCNT         (0x00000108/4) /* Error-free Frames transmitted */
79 #define GEM_TXBCNT        (0x0000010C/4) /* Error-free Broadcast Frames */
80 #define GEM_TXMCNT        (0x00000110/4) /* Error-free Multicast Frame */
81 #define GEM_TXPAUSECNT    (0x00000114/4) /* Pause Frames Transmitted */
82 #define GEM_TX64CNT       (0x00000118/4) /* Error-free 64 TX */
83 #define GEM_TX65CNT       (0x0000011C/4) /* Error-free 65-127 TX */
84 #define GEM_TX128CNT      (0x00000120/4) /* Error-free 128-255 TX */
85 #define GEM_TX256CNT      (0x00000124/4) /* Error-free 256-511 */
86 #define GEM_TX512CNT      (0x00000128/4) /* Error-free 512-1023 TX */
87 #define GEM_TX1024CNT     (0x0000012C/4) /* Error-free 1024-1518 TX */
88 #define GEM_TX1519CNT     (0x00000130/4) /* Error-free larger than 1519 TX */
89 #define GEM_TXURUNCNT     (0x00000134/4) /* TX under run error counter */
90 #define GEM_SINGLECOLLCNT (0x00000138/4) /* Single Collision Frames */
91 #define GEM_MULTCOLLCNT   (0x0000013C/4) /* Multiple Collision Frames */
92 #define GEM_EXCESSCOLLCNT (0x00000140/4) /* Excessive Collision Frames */
93 #define GEM_LATECOLLCNT   (0x00000144/4) /* Late Collision Frames */
94 #define GEM_DEFERTXCNT    (0x00000148/4) /* Deferred Transmission Frames */
95 #define GEM_CSENSECNT     (0x0000014C/4) /* Carrier Sense Error Counter */
96 #define GEM_OCTRXLO       (0x00000150/4) /* Octects Received register Low */
97 #define GEM_OCTRXHI       (0x00000154/4) /* Octects Received register High */
98 #define GEM_RXCNT         (0x00000158/4) /* Error-free Frames Received */
99 #define GEM_RXBROADCNT    (0x0000015C/4) /* Error-free Broadcast Frames RX */
100 #define GEM_RXMULTICNT    (0x00000160/4) /* Error-free Multicast Frames RX */
101 #define GEM_RXPAUSECNT    (0x00000164/4) /* Pause Frames Received Counter */
102 #define GEM_RX64CNT       (0x00000168/4) /* Error-free 64 byte Frames RX */
103 #define GEM_RX65CNT       (0x0000016C/4) /* Error-free 65-127B Frames RX */
104 #define GEM_RX128CNT      (0x00000170/4) /* Error-free 128-255B Frames RX */
105 #define GEM_RX256CNT      (0x00000174/4) /* Error-free 256-512B Frames RX */
106 #define GEM_RX512CNT      (0x00000178/4) /* Error-free 512-1023B Frames RX */
107 #define GEM_RX1024CNT     (0x0000017C/4) /* Error-free 1024-1518B Frames RX */
108 #define GEM_RX1519CNT     (0x00000180/4) /* Error-free 1519-max Frames RX */
109 #define GEM_RXUNDERCNT    (0x00000184/4) /* Undersize Frames Received */
110 #define GEM_RXOVERCNT     (0x00000188/4) /* Oversize Frames Received */
111 #define GEM_RXJABCNT      (0x0000018C/4) /* Jabbers Received Counter */
112 #define GEM_RXFCSCNT      (0x00000190/4) /* Frame Check seq. Error Counter */
113 #define GEM_RXLENERRCNT   (0x00000194/4) /* Length Field Error Counter */
114 #define GEM_RXSYMERRCNT   (0x00000198/4) /* Symbol Error Counter */
115 #define GEM_RXALIGNERRCNT (0x0000019C/4) /* Alignment Error Counter */
116 #define GEM_RXRSCERRCNT   (0x000001A0/4) /* Receive Resource Error Counter */
117 #define GEM_RXORUNCNT     (0x000001A4/4) /* Receive Overrun Counter */
118 #define GEM_RXIPCSERRCNT  (0x000001A8/4) /* IP header Checksum Error Counter */
119 #define GEM_RXTCPCCNT     (0x000001AC/4) /* TCP Checksum Error Counter */
120 #define GEM_RXUDPCCNT     (0x000001B0/4) /* UDP Checksum Error Counter */
121 
122 #define GEM_1588S         (0x000001D0/4) /* 1588 Timer Seconds */
123 #define GEM_1588NS        (0x000001D4/4) /* 1588 Timer Nanoseconds */
124 #define GEM_1588ADJ       (0x000001D8/4) /* 1588 Timer Adjust */
125 #define GEM_1588INC       (0x000001DC/4) /* 1588 Timer Increment */
126 #define GEM_PTPETXS       (0x000001E0/4) /* PTP Event Frame Transmitted (s) */
127 #define GEM_PTPETXNS      (0x000001E4/4) /* PTP Event Frame Transmitted (ns) */
128 #define GEM_PTPERXS       (0x000001E8/4) /* PTP Event Frame Received (s) */
129 #define GEM_PTPERXNS      (0x000001EC/4) /* PTP Event Frame Received (ns) */
130 #define GEM_PTPPTXS       (0x000001E0/4) /* PTP Peer Frame Transmitted (s) */
131 #define GEM_PTPPTXNS      (0x000001E4/4) /* PTP Peer Frame Transmitted (ns) */
132 #define GEM_PTPPRXS       (0x000001E8/4) /* PTP Peer Frame Received (s) */
133 #define GEM_PTPPRXNS      (0x000001EC/4) /* PTP Peer Frame Received (ns) */
134 
135 /* Design Configuration Registers */
136 #define GEM_DESCONF       (0x00000280/4)
137 #define GEM_DESCONF2      (0x00000284/4)
138 #define GEM_DESCONF3      (0x00000288/4)
139 #define GEM_DESCONF4      (0x0000028C/4)
140 #define GEM_DESCONF5      (0x00000290/4)
141 #define GEM_DESCONF6      (0x00000294/4)
142 #define GEM_DESCONF7      (0x00000298/4)
143 
144 #define GEM_MAXREG        (0x00000640/4) /* Last valid GEM address */
145 
146 /*****************************************/
147 #define GEM_NWCTRL_TXSTART     0x00000200 /* Transmit Enable */
148 #define GEM_NWCTRL_TXENA       0x00000008 /* Transmit Enable */
149 #define GEM_NWCTRL_RXENA       0x00000004 /* Receive Enable */
150 #define GEM_NWCTRL_LOCALLOOP   0x00000002 /* Local Loopback */
151 
152 #define GEM_NWCFG_STRIP_FCS    0x00020000 /* Strip FCS field */
153 #define GEM_NWCFG_LERR_DISC    0x00010000 /* Discard RX frames with lenth err */
154 #define GEM_NWCFG_BUFF_OFST_M  0x0000C000 /* Receive buffer offset mask */
155 #define GEM_NWCFG_BUFF_OFST_S  14         /* Receive buffer offset shift */
156 #define GEM_NWCFG_UCAST_HASH   0x00000080 /* accept unicast if hash match */
157 #define GEM_NWCFG_MCAST_HASH   0x00000040 /* accept multicast if hash match */
158 #define GEM_NWCFG_BCAST_REJ    0x00000020 /* Reject broadcast packets */
159 #define GEM_NWCFG_PROMISC      0x00000010 /* Accept all packets */
160 
161 #define GEM_DMACFG_RBUFSZ_M    0x007F0000 /* DMA RX Buffer Size mask */
162 #define GEM_DMACFG_RBUFSZ_S    16         /* DMA RX Buffer Size shift */
163 #define GEM_DMACFG_RBUFSZ_MUL  64         /* DMA RX Buffer Size multiplier */
164 #define GEM_DMACFG_TXCSUM_OFFL 0x00000800 /* Transmit checksum offload */
165 
166 #define GEM_TXSTATUS_TXCMPL    0x00000020 /* Transmit Complete */
167 #define GEM_TXSTATUS_USED      0x00000001 /* sw owned descriptor encountered */
168 
169 #define GEM_RXSTATUS_FRMRCVD   0x00000002 /* Frame received */
170 #define GEM_RXSTATUS_NOBUF     0x00000001 /* Buffer unavailable */
171 
172 /* GEM_ISR GEM_IER GEM_IDR GEM_IMR */
173 #define GEM_INT_TXCMPL        0x00000080 /* Transmit Complete */
174 #define GEM_INT_TXUSED         0x00000008
175 #define GEM_INT_RXUSED         0x00000004
176 #define GEM_INT_RXCMPL        0x00000002
177 
178 #define GEM_PHYMNTNC_OP_R      0x20000000 /* read operation */
179 #define GEM_PHYMNTNC_OP_W      0x10000000 /* write operation */
180 #define GEM_PHYMNTNC_ADDR      0x0F800000 /* Address bits */
181 #define GEM_PHYMNTNC_ADDR_SHFT 23
182 #define GEM_PHYMNTNC_REG       0x007C0000 /* register bits */
183 #define GEM_PHYMNTNC_REG_SHIFT 18
184 
185 /* Marvell PHY definitions */
186 #define BOARD_PHY_ADDRESS    23 /* PHY address we will emulate a device at */
187 
188 #define PHY_REG_CONTROL      0
189 #define PHY_REG_STATUS       1
190 #define PHY_REG_PHYID1       2
191 #define PHY_REG_PHYID2       3
192 #define PHY_REG_ANEGADV      4
193 #define PHY_REG_LINKPABIL    5
194 #define PHY_REG_ANEGEXP      6
195 #define PHY_REG_NEXTP        7
196 #define PHY_REG_LINKPNEXTP   8
197 #define PHY_REG_100BTCTRL    9
198 #define PHY_REG_1000BTSTAT   10
199 #define PHY_REG_EXTSTAT      15
200 #define PHY_REG_PHYSPCFC_CTL 16
201 #define PHY_REG_PHYSPCFC_ST  17
202 #define PHY_REG_INT_EN       18
203 #define PHY_REG_INT_ST       19
204 #define PHY_REG_EXT_PHYSPCFC_CTL  20
205 #define PHY_REG_RXERR        21
206 #define PHY_REG_EACD         22
207 #define PHY_REG_LED          24
208 #define PHY_REG_LED_OVRD     25
209 #define PHY_REG_EXT_PHYSPCFC_CTL2 26
210 #define PHY_REG_EXT_PHYSPCFC_ST   27
211 #define PHY_REG_CABLE_DIAG   28
212 
213 #define PHY_REG_CONTROL_RST  0x8000
214 #define PHY_REG_CONTROL_LOOP 0x4000
215 #define PHY_REG_CONTROL_ANEG 0x1000
216 
217 #define PHY_REG_STATUS_LINK     0x0004
218 #define PHY_REG_STATUS_ANEGCMPL 0x0020
219 
220 #define PHY_REG_INT_ST_ANEGCMPL 0x0800
221 #define PHY_REG_INT_ST_LINKC    0x0400
222 #define PHY_REG_INT_ST_ENERGY   0x0010
223 
224 /***********************************************************************/
225 #define GEM_RX_REJECT  1
226 #define GEM_RX_ACCEPT  0
227 
228 /***********************************************************************/
229 
230 #define DESC_1_USED 0x80000000
231 #define DESC_1_LENGTH 0x00001FFF
232 
233 #define DESC_1_TX_WRAP 0x40000000
234 #define DESC_1_TX_LAST 0x00008000
235 
236 #define DESC_0_RX_WRAP 0x00000002
237 #define DESC_0_RX_OWNERSHIP 0x00000001
238 
239 #define DESC_1_RX_SOF 0x00004000
240 #define DESC_1_RX_EOF 0x00008000
241 
242 static inline unsigned tx_desc_get_buffer(unsigned *desc)
243 {
244     return desc[0];
245 }
246 
247 static inline unsigned tx_desc_get_used(unsigned *desc)
248 {
249     return (desc[1] & DESC_1_USED) ? 1 : 0;
250 }
251 
252 static inline void tx_desc_set_used(unsigned *desc)
253 {
254     desc[1] |= DESC_1_USED;
255 }
256 
257 static inline unsigned tx_desc_get_wrap(unsigned *desc)
258 {
259     return (desc[1] & DESC_1_TX_WRAP) ? 1 : 0;
260 }
261 
262 static inline unsigned tx_desc_get_last(unsigned *desc)
263 {
264     return (desc[1] & DESC_1_TX_LAST) ? 1 : 0;
265 }
266 
267 static inline unsigned tx_desc_get_length(unsigned *desc)
268 {
269     return desc[1] & DESC_1_LENGTH;
270 }
271 
272 static inline void print_gem_tx_desc(unsigned *desc)
273 {
274     DB_PRINT("TXDESC:\n");
275     DB_PRINT("bufaddr: 0x%08x\n", *desc);
276     DB_PRINT("used_hw: %d\n", tx_desc_get_used(desc));
277     DB_PRINT("wrap:    %d\n", tx_desc_get_wrap(desc));
278     DB_PRINT("last:    %d\n", tx_desc_get_last(desc));
279     DB_PRINT("length:  %d\n", tx_desc_get_length(desc));
280 }
281 
282 static inline unsigned rx_desc_get_buffer(unsigned *desc)
283 {
284     return desc[0] & ~0x3UL;
285 }
286 
287 static inline unsigned rx_desc_get_wrap(unsigned *desc)
288 {
289     return desc[0] & DESC_0_RX_WRAP ? 1 : 0;
290 }
291 
292 static inline unsigned rx_desc_get_ownership(unsigned *desc)
293 {
294     return desc[0] & DESC_0_RX_OWNERSHIP ? 1 : 0;
295 }
296 
297 static inline void rx_desc_set_ownership(unsigned *desc)
298 {
299     desc[0] |= DESC_0_RX_OWNERSHIP;
300 }
301 
302 static inline void rx_desc_set_sof(unsigned *desc)
303 {
304     desc[1] |= DESC_1_RX_SOF;
305 }
306 
307 static inline void rx_desc_set_eof(unsigned *desc)
308 {
309     desc[1] |= DESC_1_RX_EOF;
310 }
311 
312 static inline void rx_desc_set_length(unsigned *desc, unsigned len)
313 {
314     desc[1] &= ~DESC_1_LENGTH;
315     desc[1] |= len;
316 }
317 
318 #define TYPE_CADENCE_GEM "cadence_gem"
319 #define GEM(obj) OBJECT_CHECK(GemState, (obj), TYPE_CADENCE_GEM)
320 
321 typedef struct GemState {
322     SysBusDevice parent_obj;
323 
324     MemoryRegion iomem;
325     NICState *nic;
326     NICConf conf;
327     qemu_irq irq;
328 
329     /* GEM registers backing store */
330     uint32_t regs[GEM_MAXREG];
331     /* Mask of register bits which are write only */
332     uint32_t regs_wo[GEM_MAXREG];
333     /* Mask of register bits which are read only */
334     uint32_t regs_ro[GEM_MAXREG];
335     /* Mask of register bits which are clear on read */
336     uint32_t regs_rtc[GEM_MAXREG];
337     /* Mask of register bits which are write 1 to clear */
338     uint32_t regs_w1c[GEM_MAXREG];
339 
340     /* PHY registers backing store */
341     uint16_t phy_regs[32];
342 
343     uint8_t phy_loop; /* Are we in phy loopback? */
344 
345     /* The current DMA descriptor pointers */
346     uint32_t rx_desc_addr;
347     uint32_t tx_desc_addr;
348 
349 } GemState;
350 
351 /* The broadcast MAC address: 0xFFFFFFFFFFFF */
352 const uint8_t broadcast_addr[] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
353 
354 /*
355  * gem_init_register_masks:
356  * One time initialization.
357  * Set masks to identify which register bits have magical clear properties
358  */
359 static void gem_init_register_masks(GemState *s)
360 {
361     /* Mask of register bits which are read only*/
362     memset(&s->regs_ro[0], 0, sizeof(s->regs_ro));
363     s->regs_ro[GEM_NWCTRL]   = 0xFFF80000;
364     s->regs_ro[GEM_NWSTATUS] = 0xFFFFFFFF;
365     s->regs_ro[GEM_DMACFG]   = 0xFE00F000;
366     s->regs_ro[GEM_TXSTATUS] = 0xFFFFFE08;
367     s->regs_ro[GEM_RXQBASE]  = 0x00000003;
368     s->regs_ro[GEM_TXQBASE]  = 0x00000003;
369     s->regs_ro[GEM_RXSTATUS] = 0xFFFFFFF0;
370     s->regs_ro[GEM_ISR]      = 0xFFFFFFFF;
371     s->regs_ro[GEM_IMR]      = 0xFFFFFFFF;
372     s->regs_ro[GEM_MODID]    = 0xFFFFFFFF;
373 
374     /* Mask of register bits which are clear on read */
375     memset(&s->regs_rtc[0], 0, sizeof(s->regs_rtc));
376     s->regs_rtc[GEM_ISR]      = 0xFFFFFFFF;
377 
378     /* Mask of register bits which are write 1 to clear */
379     memset(&s->regs_w1c[0], 0, sizeof(s->regs_w1c));
380     s->regs_w1c[GEM_TXSTATUS] = 0x000001F7;
381     s->regs_w1c[GEM_RXSTATUS] = 0x0000000F;
382 
383     /* Mask of register bits which are write only */
384     memset(&s->regs_wo[0], 0, sizeof(s->regs_wo));
385     s->regs_wo[GEM_NWCTRL]   = 0x00073E60;
386     s->regs_wo[GEM_IER]      = 0x07FFFFFF;
387     s->regs_wo[GEM_IDR]      = 0x07FFFFFF;
388 }
389 
390 /*
391  * phy_update_link:
392  * Make the emulated PHY link state match the QEMU "interface" state.
393  */
394 static void phy_update_link(GemState *s)
395 {
396     DB_PRINT("down %d\n", qemu_get_queue(s->nic)->link_down);
397 
398     /* Autonegotiation status mirrors link status.  */
399     if (qemu_get_queue(s->nic)->link_down) {
400         s->phy_regs[PHY_REG_STATUS] &= ~(PHY_REG_STATUS_ANEGCMPL |
401                                          PHY_REG_STATUS_LINK);
402         s->phy_regs[PHY_REG_INT_ST] |= PHY_REG_INT_ST_LINKC;
403     } else {
404         s->phy_regs[PHY_REG_STATUS] |= (PHY_REG_STATUS_ANEGCMPL |
405                                          PHY_REG_STATUS_LINK);
406         s->phy_regs[PHY_REG_INT_ST] |= (PHY_REG_INT_ST_LINKC |
407                                         PHY_REG_INT_ST_ANEGCMPL |
408                                         PHY_REG_INT_ST_ENERGY);
409     }
410 }
411 
412 static int gem_can_receive(NetClientState *nc)
413 {
414     GemState *s;
415 
416     s = qemu_get_nic_opaque(nc);
417 
418     DB_PRINT("\n");
419 
420     /* Do nothing if receive is not enabled. */
421     if (!(s->regs[GEM_NWCTRL] & GEM_NWCTRL_RXENA)) {
422         return 0;
423     }
424 
425     return 1;
426 }
427 
428 /*
429  * gem_update_int_status:
430  * Raise or lower interrupt based on current status.
431  */
432 static void gem_update_int_status(GemState *s)
433 {
434     if (s->regs[GEM_ISR]) {
435         DB_PRINT("asserting int. (0x%08x)\n", s->regs[GEM_ISR]);
436         qemu_set_irq(s->irq, 1);
437     }
438 }
439 
440 /*
441  * gem_receive_updatestats:
442  * Increment receive statistics.
443  */
444 static void gem_receive_updatestats(GemState *s, const uint8_t *packet,
445                                     unsigned bytes)
446 {
447     uint64_t octets;
448 
449     /* Total octets (bytes) received */
450     octets = ((uint64_t)(s->regs[GEM_OCTRXLO]) << 32) |
451              s->regs[GEM_OCTRXHI];
452     octets += bytes;
453     s->regs[GEM_OCTRXLO] = octets >> 32;
454     s->regs[GEM_OCTRXHI] = octets;
455 
456     /* Error-free Frames received */
457     s->regs[GEM_RXCNT]++;
458 
459     /* Error-free Broadcast Frames counter */
460     if (!memcmp(packet, broadcast_addr, 6)) {
461         s->regs[GEM_RXBROADCNT]++;
462     }
463 
464     /* Error-free Multicast Frames counter */
465     if (packet[0] == 0x01) {
466         s->regs[GEM_RXMULTICNT]++;
467     }
468 
469     if (bytes <= 64) {
470         s->regs[GEM_RX64CNT]++;
471     } else if (bytes <= 127) {
472         s->regs[GEM_RX65CNT]++;
473     } else if (bytes <= 255) {
474         s->regs[GEM_RX128CNT]++;
475     } else if (bytes <= 511) {
476         s->regs[GEM_RX256CNT]++;
477     } else if (bytes <= 1023) {
478         s->regs[GEM_RX512CNT]++;
479     } else if (bytes <= 1518) {
480         s->regs[GEM_RX1024CNT]++;
481     } else {
482         s->regs[GEM_RX1519CNT]++;
483     }
484 }
485 
486 /*
487  * Get the MAC Address bit from the specified position
488  */
489 static unsigned get_bit(const uint8_t *mac, unsigned bit)
490 {
491     unsigned byte;
492 
493     byte = mac[bit / 8];
494     byte >>= (bit & 0x7);
495     byte &= 1;
496 
497     return byte;
498 }
499 
500 /*
501  * Calculate a GEM MAC Address hash index
502  */
503 static unsigned calc_mac_hash(const uint8_t *mac)
504 {
505     int index_bit, mac_bit;
506     unsigned hash_index;
507 
508     hash_index = 0;
509     mac_bit = 5;
510     for (index_bit = 5; index_bit >= 0; index_bit--) {
511         hash_index |= (get_bit(mac,  mac_bit) ^
512                                get_bit(mac, mac_bit + 6) ^
513                                get_bit(mac, mac_bit + 12) ^
514                                get_bit(mac, mac_bit + 18) ^
515                                get_bit(mac, mac_bit + 24) ^
516                                get_bit(mac, mac_bit + 30) ^
517                                get_bit(mac, mac_bit + 36) ^
518                                get_bit(mac, mac_bit + 42)) << index_bit;
519         mac_bit--;
520     }
521 
522     return hash_index;
523 }
524 
525 /*
526  * gem_mac_address_filter:
527  * Accept or reject this destination address?
528  * Returns:
529  * GEM_RX_REJECT: reject
530  * GEM_RX_ACCEPT: accept
531  */
532 static int gem_mac_address_filter(GemState *s, const uint8_t *packet)
533 {
534     uint8_t *gem_spaddr;
535     int i;
536 
537     /* Promiscuous mode? */
538     if (s->regs[GEM_NWCFG] & GEM_NWCFG_PROMISC) {
539         return GEM_RX_ACCEPT;
540     }
541 
542     if (!memcmp(packet, broadcast_addr, 6)) {
543         /* Reject broadcast packets? */
544         if (s->regs[GEM_NWCFG] & GEM_NWCFG_BCAST_REJ) {
545             return GEM_RX_REJECT;
546         }
547         return GEM_RX_ACCEPT;
548     }
549 
550     /* Accept packets -w- hash match? */
551     if ((packet[0] == 0x01 && (s->regs[GEM_NWCFG] & GEM_NWCFG_MCAST_HASH)) ||
552         (packet[0] != 0x01 && (s->regs[GEM_NWCFG] & GEM_NWCFG_UCAST_HASH))) {
553         unsigned hash_index;
554 
555         hash_index = calc_mac_hash(packet);
556         if (hash_index < 32) {
557             if (s->regs[GEM_HASHLO] & (1<<hash_index)) {
558                 return GEM_RX_ACCEPT;
559             }
560         } else {
561             hash_index -= 32;
562             if (s->regs[GEM_HASHHI] & (1<<hash_index)) {
563                 return GEM_RX_ACCEPT;
564             }
565         }
566     }
567 
568     /* Check all 4 specific addresses */
569     gem_spaddr = (uint8_t *)&(s->regs[GEM_SPADDR1LO]);
570     for (i = 0; i < 4; i++) {
571         if (!memcmp(packet, gem_spaddr, 6)) {
572             return GEM_RX_ACCEPT;
573         }
574 
575         gem_spaddr += 8;
576     }
577 
578     /* No address match; reject the packet */
579     return GEM_RX_REJECT;
580 }
581 
582 /*
583  * gem_receive:
584  * Fit a packet handed to us by QEMU into the receive descriptor ring.
585  */
586 static ssize_t gem_receive(NetClientState *nc, const uint8_t *buf, size_t size)
587 {
588     unsigned    desc[2];
589     hwaddr packet_desc_addr, last_desc_addr;
590     GemState *s;
591     unsigned   rxbufsize, bytes_to_copy;
592     unsigned   rxbuf_offset;
593     uint8_t    rxbuf[2048];
594     uint8_t   *rxbuf_ptr;
595 
596     s = qemu_get_nic_opaque(nc);
597 
598     /* Do nothing if receive is not enabled. */
599     if (!gem_can_receive(nc)) {
600         return -1;
601     }
602 
603     /* Is this destination MAC address "for us" ? */
604     if (gem_mac_address_filter(s, buf) == GEM_RX_REJECT) {
605         return -1;
606     }
607 
608     /* Discard packets with receive length error enabled ? */
609     if (s->regs[GEM_NWCFG] & GEM_NWCFG_LERR_DISC) {
610         unsigned type_len;
611 
612         /* Fish the ethertype / length field out of the RX packet */
613         type_len = buf[12] << 8 | buf[13];
614         /* It is a length field, not an ethertype */
615         if (type_len < 0x600) {
616             if (size < type_len) {
617                 /* discard */
618                 return -1;
619             }
620         }
621     }
622 
623     /*
624      * Determine configured receive buffer offset (probably 0)
625      */
626     rxbuf_offset = (s->regs[GEM_NWCFG] & GEM_NWCFG_BUFF_OFST_M) >>
627                    GEM_NWCFG_BUFF_OFST_S;
628 
629     /* The configure size of each receive buffer.  Determines how many
630      * buffers needed to hold this packet.
631      */
632     rxbufsize = ((s->regs[GEM_DMACFG] & GEM_DMACFG_RBUFSZ_M) >>
633                  GEM_DMACFG_RBUFSZ_S) * GEM_DMACFG_RBUFSZ_MUL;
634     bytes_to_copy = size;
635 
636     /* Strip of FCS field ? (usually yes) */
637     if (s->regs[GEM_NWCFG] & GEM_NWCFG_STRIP_FCS) {
638         rxbuf_ptr = (void *)buf;
639     } else {
640         unsigned crc_val;
641         int      crc_offset;
642 
643         /* The application wants the FCS field, which QEMU does not provide.
644          * We must try and caclculate one.
645          */
646 
647         memcpy(rxbuf, buf, size);
648         memset(rxbuf + size, 0, sizeof(rxbuf) - size);
649         rxbuf_ptr = rxbuf;
650         crc_val = cpu_to_le32(crc32(0, rxbuf, MAX(size, 60)));
651         if (size < 60) {
652             crc_offset = 60;
653         } else {
654             crc_offset = size;
655         }
656         memcpy(rxbuf + crc_offset, &crc_val, sizeof(crc_val));
657 
658         bytes_to_copy += 4;
659         size += 4;
660     }
661 
662     /* Pad to minimum length */
663     if (size < 64) {
664         size = 64;
665     }
666 
667     DB_PRINT("config bufsize: %d packet size: %ld\n", rxbufsize, size);
668 
669     packet_desc_addr = s->rx_desc_addr;
670     while (1) {
671         DB_PRINT("read descriptor 0x%x\n", (unsigned)packet_desc_addr);
672         /* read current descriptor */
673         cpu_physical_memory_read(packet_desc_addr,
674                                  (uint8_t *)&desc[0], sizeof(desc));
675 
676         /* Descriptor owned by software ? */
677         if (rx_desc_get_ownership(desc) == 1) {
678             DB_PRINT("descriptor 0x%x owned by sw.\n",
679                      (unsigned)packet_desc_addr);
680             s->regs[GEM_RXSTATUS] |= GEM_RXSTATUS_NOBUF;
681             s->regs[GEM_ISR] |= GEM_INT_RXUSED & ~(s->regs[GEM_IMR]);
682             /* Handle interrupt consequences */
683             gem_update_int_status(s);
684             return -1;
685         }
686 
687         DB_PRINT("copy %d bytes to 0x%x\n", MIN(bytes_to_copy, rxbufsize),
688                 rx_desc_get_buffer(desc));
689 
690         /*
691          * Let's have QEMU lend a helping hand.
692          */
693         if (rx_desc_get_buffer(desc) == 0) {
694             DB_PRINT("Invalid RX buffer (NULL) for descriptor 0x%x\n",
695                      (unsigned)packet_desc_addr);
696             break;
697         }
698 
699         /* Copy packet data to emulated DMA buffer */
700         cpu_physical_memory_write(rx_desc_get_buffer(desc) + rxbuf_offset,
701                                   rxbuf_ptr, MIN(bytes_to_copy, rxbufsize));
702         bytes_to_copy -= MIN(bytes_to_copy, rxbufsize);
703         rxbuf_ptr += MIN(bytes_to_copy, rxbufsize);
704         if (bytes_to_copy == 0) {
705             break;
706         }
707 
708         /* Next descriptor */
709         if (rx_desc_get_wrap(desc)) {
710             packet_desc_addr = s->regs[GEM_RXQBASE];
711         } else {
712             packet_desc_addr += 8;
713         }
714     }
715 
716     DB_PRINT("set length: %ld, EOF on descriptor 0x%x\n", size,
717             (unsigned)packet_desc_addr);
718 
719     /* Update last descriptor with EOF and total length */
720     rx_desc_set_eof(desc);
721     rx_desc_set_length(desc, size);
722     cpu_physical_memory_write(packet_desc_addr,
723                               (uint8_t *)&desc[0], sizeof(desc));
724 
725     /* Advance RX packet descriptor Q */
726     last_desc_addr = packet_desc_addr;
727     packet_desc_addr = s->rx_desc_addr;
728     s->rx_desc_addr = last_desc_addr;
729     if (rx_desc_get_wrap(desc)) {
730         s->rx_desc_addr = s->regs[GEM_RXQBASE];
731         DB_PRINT("wrapping RX descriptor list\n");
732     } else {
733         DB_PRINT("incrementing RX descriptor list\n");
734         s->rx_desc_addr += 8;
735     }
736 
737     DB_PRINT("set SOF, OWN on descriptor 0x%08x\n", (unsigned)packet_desc_addr);
738 
739     /* Count it */
740     gem_receive_updatestats(s, buf, size);
741 
742     /* Update first descriptor (which could also be the last) */
743     /* read descriptor */
744     cpu_physical_memory_read(packet_desc_addr,
745                              (uint8_t *)&desc[0], sizeof(desc));
746     rx_desc_set_sof(desc);
747     rx_desc_set_ownership(desc);
748     cpu_physical_memory_write(packet_desc_addr,
749                               (uint8_t *)&desc[0], sizeof(desc));
750 
751     s->regs[GEM_RXSTATUS] |= GEM_RXSTATUS_FRMRCVD;
752     s->regs[GEM_ISR] |= GEM_INT_RXCMPL & ~(s->regs[GEM_IMR]);
753 
754     /* Handle interrupt consequences */
755     gem_update_int_status(s);
756 
757     return size;
758 }
759 
760 /*
761  * gem_transmit_updatestats:
762  * Increment transmit statistics.
763  */
764 static void gem_transmit_updatestats(GemState *s, const uint8_t *packet,
765                                      unsigned bytes)
766 {
767     uint64_t octets;
768 
769     /* Total octets (bytes) transmitted */
770     octets = ((uint64_t)(s->regs[GEM_OCTTXLO]) << 32) |
771              s->regs[GEM_OCTTXHI];
772     octets += bytes;
773     s->regs[GEM_OCTTXLO] = octets >> 32;
774     s->regs[GEM_OCTTXHI] = octets;
775 
776     /* Error-free Frames transmitted */
777     s->regs[GEM_TXCNT]++;
778 
779     /* Error-free Broadcast Frames counter */
780     if (!memcmp(packet, broadcast_addr, 6)) {
781         s->regs[GEM_TXBCNT]++;
782     }
783 
784     /* Error-free Multicast Frames counter */
785     if (packet[0] == 0x01) {
786         s->regs[GEM_TXMCNT]++;
787     }
788 
789     if (bytes <= 64) {
790         s->regs[GEM_TX64CNT]++;
791     } else if (bytes <= 127) {
792         s->regs[GEM_TX65CNT]++;
793     } else if (bytes <= 255) {
794         s->regs[GEM_TX128CNT]++;
795     } else if (bytes <= 511) {
796         s->regs[GEM_TX256CNT]++;
797     } else if (bytes <= 1023) {
798         s->regs[GEM_TX512CNT]++;
799     } else if (bytes <= 1518) {
800         s->regs[GEM_TX1024CNT]++;
801     } else {
802         s->regs[GEM_TX1519CNT]++;
803     }
804 }
805 
806 /*
807  * gem_transmit:
808  * Fish packets out of the descriptor ring and feed them to QEMU
809  */
810 static void gem_transmit(GemState *s)
811 {
812     unsigned    desc[2];
813     hwaddr packet_desc_addr;
814     uint8_t     tx_packet[2048];
815     uint8_t     *p;
816     unsigned    total_bytes;
817 
818     /* Do nothing if transmit is not enabled. */
819     if (!(s->regs[GEM_NWCTRL] & GEM_NWCTRL_TXENA)) {
820         return;
821     }
822 
823     DB_PRINT("\n");
824 
825     /* The packet we will hand off to qemu.
826      * Packets scattered across multiple descriptors are gathered to this
827      * one contiguous buffer first.
828      */
829     p = tx_packet;
830     total_bytes = 0;
831 
832     /* read current descriptor */
833     packet_desc_addr = s->tx_desc_addr;
834     cpu_physical_memory_read(packet_desc_addr,
835                              (uint8_t *)&desc[0], sizeof(desc));
836     /* Handle all descriptors owned by hardware */
837     while (tx_desc_get_used(desc) == 0) {
838 
839         /* Do nothing if transmit is not enabled. */
840         if (!(s->regs[GEM_NWCTRL] & GEM_NWCTRL_TXENA)) {
841             return;
842         }
843         print_gem_tx_desc(desc);
844 
845         /* The real hardware would eat this (and possibly crash).
846          * For QEMU let's lend a helping hand.
847          */
848         if ((tx_desc_get_buffer(desc) == 0) ||
849             (tx_desc_get_length(desc) == 0)) {
850             DB_PRINT("Invalid TX descriptor @ 0x%x\n",
851                      (unsigned)packet_desc_addr);
852             break;
853         }
854 
855         /* Gather this fragment of the packet from "dma memory" to our contig.
856          * buffer.
857          */
858         cpu_physical_memory_read(tx_desc_get_buffer(desc), p,
859                                  tx_desc_get_length(desc));
860         p += tx_desc_get_length(desc);
861         total_bytes += tx_desc_get_length(desc);
862 
863         /* Last descriptor for this packet; hand the whole thing off */
864         if (tx_desc_get_last(desc)) {
865             /* Modify the 1st descriptor of this packet to be owned by
866              * the processor.
867              */
868             cpu_physical_memory_read(s->tx_desc_addr,
869                                      (uint8_t *)&desc[0], sizeof(desc));
870             tx_desc_set_used(desc);
871             cpu_physical_memory_write(s->tx_desc_addr,
872                                       (uint8_t *)&desc[0], sizeof(desc));
873             /* Advance the hardare current descriptor past this packet */
874             if (tx_desc_get_wrap(desc)) {
875                 s->tx_desc_addr = s->regs[GEM_TXQBASE];
876             } else {
877                 s->tx_desc_addr = packet_desc_addr + 8;
878             }
879             DB_PRINT("TX descriptor next: 0x%08x\n", s->tx_desc_addr);
880 
881             s->regs[GEM_TXSTATUS] |= GEM_TXSTATUS_TXCMPL;
882             s->regs[GEM_ISR] |= GEM_INT_TXCMPL & ~(s->regs[GEM_IMR]);
883 
884             /* Handle interrupt consequences */
885             gem_update_int_status(s);
886 
887             /* Is checksum offload enabled? */
888             if (s->regs[GEM_DMACFG] & GEM_DMACFG_TXCSUM_OFFL) {
889                 net_checksum_calculate(tx_packet, total_bytes);
890             }
891 
892             /* Update MAC statistics */
893             gem_transmit_updatestats(s, tx_packet, total_bytes);
894 
895             /* Send the packet somewhere */
896             if (s->phy_loop) {
897                 gem_receive(qemu_get_queue(s->nic), tx_packet, total_bytes);
898             } else {
899                 qemu_send_packet(qemu_get_queue(s->nic), tx_packet,
900                                  total_bytes);
901             }
902 
903             /* Prepare for next packet */
904             p = tx_packet;
905             total_bytes = 0;
906         }
907 
908         /* read next descriptor */
909         if (tx_desc_get_wrap(desc)) {
910             packet_desc_addr = s->regs[GEM_TXQBASE];
911         } else {
912             packet_desc_addr += 8;
913         }
914         cpu_physical_memory_read(packet_desc_addr,
915                                  (uint8_t *)&desc[0], sizeof(desc));
916     }
917 
918     if (tx_desc_get_used(desc)) {
919         s->regs[GEM_TXSTATUS] |= GEM_TXSTATUS_USED;
920         s->regs[GEM_ISR] |= GEM_INT_TXUSED & ~(s->regs[GEM_IMR]);
921         gem_update_int_status(s);
922     }
923 }
924 
925 static void gem_phy_reset(GemState *s)
926 {
927     memset(&s->phy_regs[0], 0, sizeof(s->phy_regs));
928     s->phy_regs[PHY_REG_CONTROL] = 0x1140;
929     s->phy_regs[PHY_REG_STATUS] = 0x7969;
930     s->phy_regs[PHY_REG_PHYID1] = 0x0141;
931     s->phy_regs[PHY_REG_PHYID2] = 0x0CC2;
932     s->phy_regs[PHY_REG_ANEGADV] = 0x01E1;
933     s->phy_regs[PHY_REG_LINKPABIL] = 0xCDE1;
934     s->phy_regs[PHY_REG_ANEGEXP] = 0x000F;
935     s->phy_regs[PHY_REG_NEXTP] = 0x2001;
936     s->phy_regs[PHY_REG_LINKPNEXTP] = 0x40E6;
937     s->phy_regs[PHY_REG_100BTCTRL] = 0x0300;
938     s->phy_regs[PHY_REG_1000BTSTAT] = 0x7C00;
939     s->phy_regs[PHY_REG_EXTSTAT] = 0x3000;
940     s->phy_regs[PHY_REG_PHYSPCFC_CTL] = 0x0078;
941     s->phy_regs[PHY_REG_PHYSPCFC_ST] = 0xBC00;
942     s->phy_regs[PHY_REG_EXT_PHYSPCFC_CTL] = 0x0C60;
943     s->phy_regs[PHY_REG_LED] = 0x4100;
944     s->phy_regs[PHY_REG_EXT_PHYSPCFC_CTL2] = 0x000A;
945     s->phy_regs[PHY_REG_EXT_PHYSPCFC_ST] = 0x848B;
946 
947     phy_update_link(s);
948 }
949 
950 static void gem_reset(DeviceState *d)
951 {
952     GemState *s = GEM(d);
953 
954     DB_PRINT("\n");
955 
956     /* Set post reset register values */
957     memset(&s->regs[0], 0, sizeof(s->regs));
958     s->regs[GEM_NWCFG] = 0x00080000;
959     s->regs[GEM_NWSTATUS] = 0x00000006;
960     s->regs[GEM_DMACFG] = 0x00020784;
961     s->regs[GEM_IMR] = 0x07ffffff;
962     s->regs[GEM_TXPAUSE] = 0x0000ffff;
963     s->regs[GEM_TXPARTIALSF] = 0x000003ff;
964     s->regs[GEM_RXPARTIALSF] = 0x000003ff;
965     s->regs[GEM_MODID] = 0x00020118;
966     s->regs[GEM_DESCONF] = 0x02500111;
967     s->regs[GEM_DESCONF2] = 0x2ab13fff;
968     s->regs[GEM_DESCONF5] = 0x002f2145;
969     s->regs[GEM_DESCONF6] = 0x00000200;
970 
971     gem_phy_reset(s);
972 
973     gem_update_int_status(s);
974 }
975 
976 static uint16_t gem_phy_read(GemState *s, unsigned reg_num)
977 {
978     DB_PRINT("reg: %d value: 0x%04x\n", reg_num, s->phy_regs[reg_num]);
979     return s->phy_regs[reg_num];
980 }
981 
982 static void gem_phy_write(GemState *s, unsigned reg_num, uint16_t val)
983 {
984     DB_PRINT("reg: %d value: 0x%04x\n", reg_num, val);
985 
986     switch (reg_num) {
987     case PHY_REG_CONTROL:
988         if (val & PHY_REG_CONTROL_RST) {
989             /* Phy reset */
990             gem_phy_reset(s);
991             val &= ~(PHY_REG_CONTROL_RST | PHY_REG_CONTROL_LOOP);
992             s->phy_loop = 0;
993         }
994         if (val & PHY_REG_CONTROL_ANEG) {
995             /* Complete autonegotiation immediately */
996             val &= ~PHY_REG_CONTROL_ANEG;
997             s->phy_regs[PHY_REG_STATUS] |= PHY_REG_STATUS_ANEGCMPL;
998         }
999         if (val & PHY_REG_CONTROL_LOOP) {
1000             DB_PRINT("PHY placed in loopback\n");
1001             s->phy_loop = 1;
1002         } else {
1003             s->phy_loop = 0;
1004         }
1005         break;
1006     }
1007     s->phy_regs[reg_num] = val;
1008 }
1009 
1010 /*
1011  * gem_read32:
1012  * Read a GEM register.
1013  */
1014 static uint64_t gem_read(void *opaque, hwaddr offset, unsigned size)
1015 {
1016     GemState *s;
1017     uint32_t retval;
1018 
1019     s = (GemState *)opaque;
1020 
1021     offset >>= 2;
1022     retval = s->regs[offset];
1023 
1024     DB_PRINT("offset: 0x%04x read: 0x%08x\n", (unsigned)offset*4, retval);
1025 
1026     switch (offset) {
1027     case GEM_ISR:
1028         DB_PRINT("lowering irq on ISR read\n");
1029         qemu_set_irq(s->irq, 0);
1030         break;
1031     case GEM_PHYMNTNC:
1032         if (retval & GEM_PHYMNTNC_OP_R) {
1033             uint32_t phy_addr, reg_num;
1034 
1035             phy_addr = (retval & GEM_PHYMNTNC_ADDR) >> GEM_PHYMNTNC_ADDR_SHFT;
1036             if (phy_addr == BOARD_PHY_ADDRESS) {
1037                 reg_num = (retval & GEM_PHYMNTNC_REG) >> GEM_PHYMNTNC_REG_SHIFT;
1038                 retval &= 0xFFFF0000;
1039                 retval |= gem_phy_read(s, reg_num);
1040             } else {
1041                 retval |= 0xFFFF; /* No device at this address */
1042             }
1043         }
1044         break;
1045     }
1046 
1047     /* Squash read to clear bits */
1048     s->regs[offset] &= ~(s->regs_rtc[offset]);
1049 
1050     /* Do not provide write only bits */
1051     retval &= ~(s->regs_wo[offset]);
1052 
1053     DB_PRINT("0x%08x\n", retval);
1054     return retval;
1055 }
1056 
1057 /*
1058  * gem_write32:
1059  * Write a GEM register.
1060  */
1061 static void gem_write(void *opaque, hwaddr offset, uint64_t val,
1062         unsigned size)
1063 {
1064     GemState *s = (GemState *)opaque;
1065     uint32_t readonly;
1066 
1067     DB_PRINT("offset: 0x%04x write: 0x%08x ", (unsigned)offset, (unsigned)val);
1068     offset >>= 2;
1069 
1070     /* Squash bits which are read only in write value */
1071     val &= ~(s->regs_ro[offset]);
1072     /* Preserve (only) bits which are read only in register */
1073     readonly = s->regs[offset];
1074     readonly &= s->regs_ro[offset];
1075 
1076     /* Squash bits which are write 1 to clear */
1077     val &= ~(s->regs_w1c[offset] & val);
1078 
1079     /* Copy register write to backing store */
1080     s->regs[offset] = val | readonly;
1081 
1082     /* Handle register write side effects */
1083     switch (offset) {
1084     case GEM_NWCTRL:
1085         if (val & GEM_NWCTRL_TXSTART) {
1086             gem_transmit(s);
1087         }
1088         if (!(val & GEM_NWCTRL_TXENA)) {
1089             /* Reset to start of Q when transmit disabled. */
1090             s->tx_desc_addr = s->regs[GEM_TXQBASE];
1091         }
1092         if (val & GEM_NWCTRL_RXENA) {
1093             qemu_flush_queued_packets(qemu_get_queue(s->nic));
1094         }
1095         break;
1096 
1097     case GEM_TXSTATUS:
1098         gem_update_int_status(s);
1099         break;
1100     case GEM_RXQBASE:
1101         s->rx_desc_addr = val;
1102         break;
1103     case GEM_TXQBASE:
1104         s->tx_desc_addr = val;
1105         break;
1106     case GEM_RXSTATUS:
1107         gem_update_int_status(s);
1108         break;
1109     case GEM_IER:
1110         s->regs[GEM_IMR] &= ~val;
1111         gem_update_int_status(s);
1112         break;
1113     case GEM_IDR:
1114         s->regs[GEM_IMR] |= val;
1115         gem_update_int_status(s);
1116         break;
1117     case GEM_PHYMNTNC:
1118         if (val & GEM_PHYMNTNC_OP_W) {
1119             uint32_t phy_addr, reg_num;
1120 
1121             phy_addr = (val & GEM_PHYMNTNC_ADDR) >> GEM_PHYMNTNC_ADDR_SHFT;
1122             if (phy_addr == BOARD_PHY_ADDRESS) {
1123                 reg_num = (val & GEM_PHYMNTNC_REG) >> GEM_PHYMNTNC_REG_SHIFT;
1124                 gem_phy_write(s, reg_num, val);
1125             }
1126         }
1127         break;
1128     }
1129 
1130     DB_PRINT("newval: 0x%08x\n", s->regs[offset]);
1131 }
1132 
1133 static const MemoryRegionOps gem_ops = {
1134     .read = gem_read,
1135     .write = gem_write,
1136     .endianness = DEVICE_LITTLE_ENDIAN,
1137 };
1138 
1139 static void gem_cleanup(NetClientState *nc)
1140 {
1141     GemState *s = qemu_get_nic_opaque(nc);
1142 
1143     DB_PRINT("\n");
1144     s->nic = NULL;
1145 }
1146 
1147 static void gem_set_link(NetClientState *nc)
1148 {
1149     DB_PRINT("\n");
1150     phy_update_link(qemu_get_nic_opaque(nc));
1151 }
1152 
1153 static NetClientInfo net_gem_info = {
1154     .type = NET_CLIENT_OPTIONS_KIND_NIC,
1155     .size = sizeof(NICState),
1156     .can_receive = gem_can_receive,
1157     .receive = gem_receive,
1158     .cleanup = gem_cleanup,
1159     .link_status_changed = gem_set_link,
1160 };
1161 
1162 static int gem_init(SysBusDevice *sbd)
1163 {
1164     DeviceState *dev = DEVICE(sbd);
1165     GemState *s = GEM(dev);
1166 
1167     DB_PRINT("\n");
1168 
1169     gem_init_register_masks(s);
1170     memory_region_init_io(&s->iomem, OBJECT(s), &gem_ops, s,
1171                           "enet", sizeof(s->regs));
1172     sysbus_init_mmio(sbd, &s->iomem);
1173     sysbus_init_irq(sbd, &s->irq);
1174     qemu_macaddr_default_if_unset(&s->conf.macaddr);
1175 
1176     s->nic = qemu_new_nic(&net_gem_info, &s->conf,
1177             object_get_typename(OBJECT(dev)), dev->id, s);
1178 
1179     return 0;
1180 }
1181 
1182 static const VMStateDescription vmstate_cadence_gem = {
1183     .name = "cadence_gem",
1184     .version_id = 1,
1185     .minimum_version_id = 1,
1186     .minimum_version_id_old = 1,
1187     .fields      = (VMStateField[]) {
1188         VMSTATE_UINT32_ARRAY(regs, GemState, GEM_MAXREG),
1189         VMSTATE_UINT16_ARRAY(phy_regs, GemState, 32),
1190         VMSTATE_UINT8(phy_loop, GemState),
1191         VMSTATE_UINT32(rx_desc_addr, GemState),
1192         VMSTATE_UINT32(tx_desc_addr, GemState),
1193     }
1194 };
1195 
1196 static Property gem_properties[] = {
1197     DEFINE_NIC_PROPERTIES(GemState, conf),
1198     DEFINE_PROP_END_OF_LIST(),
1199 };
1200 
1201 static void gem_class_init(ObjectClass *klass, void *data)
1202 {
1203     DeviceClass *dc = DEVICE_CLASS(klass);
1204     SysBusDeviceClass *sdc = SYS_BUS_DEVICE_CLASS(klass);
1205 
1206     sdc->init = gem_init;
1207     dc->props = gem_properties;
1208     dc->vmsd = &vmstate_cadence_gem;
1209     dc->reset = gem_reset;
1210 }
1211 
1212 static const TypeInfo gem_info = {
1213     .name  = TYPE_CADENCE_GEM,
1214     .parent = TYPE_SYS_BUS_DEVICE,
1215     .instance_size  = sizeof(GemState),
1216     .class_init = gem_class_init,
1217 };
1218 
1219 static void gem_register_types(void)
1220 {
1221     type_register_static(&gem_info);
1222 }
1223 
1224 type_init(gem_register_types)
1225