xref: /openbmc/qemu/hw/net/cadence_gem.c (revision 61b9251a)
1 /*
2  * QEMU Cadence 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/net/cadence_gem.h"
28 #include "net/checksum.h"
29 
30 #ifdef CADENCE_GEM_ERR_DEBUG
31 #define DB_PRINT(...) do { \
32     fprintf(stderr,  ": %s: ", __func__); \
33     fprintf(stderr, ## __VA_ARGS__); \
34     } while (0);
35 #else
36     #define DB_PRINT(...)
37 #endif
38 
39 #define GEM_NWCTRL        (0x00000000/4) /* Network Control reg */
40 #define GEM_NWCFG         (0x00000004/4) /* Network Config reg */
41 #define GEM_NWSTATUS      (0x00000008/4) /* Network Status reg */
42 #define GEM_USERIO        (0x0000000C/4) /* User IO reg */
43 #define GEM_DMACFG        (0x00000010/4) /* DMA Control reg */
44 #define GEM_TXSTATUS      (0x00000014/4) /* TX Status reg */
45 #define GEM_RXQBASE       (0x00000018/4) /* RX Q Base address reg */
46 #define GEM_TXQBASE       (0x0000001C/4) /* TX Q Base address reg */
47 #define GEM_RXSTATUS      (0x00000020/4) /* RX Status reg */
48 #define GEM_ISR           (0x00000024/4) /* Interrupt Status reg */
49 #define GEM_IER           (0x00000028/4) /* Interrupt Enable reg */
50 #define GEM_IDR           (0x0000002C/4) /* Interrupt Disable reg */
51 #define GEM_IMR           (0x00000030/4) /* Interrupt Mask reg */
52 #define GEM_PHYMNTNC      (0x00000034/4) /* Phy Maintenance reg */
53 #define GEM_RXPAUSE       (0x00000038/4) /* RX Pause Time reg */
54 #define GEM_TXPAUSE       (0x0000003C/4) /* TX Pause Time reg */
55 #define GEM_TXPARTIALSF   (0x00000040/4) /* TX Partial Store and Forward */
56 #define GEM_RXPARTIALSF   (0x00000044/4) /* RX Partial Store and Forward */
57 #define GEM_HASHLO        (0x00000080/4) /* Hash Low address reg */
58 #define GEM_HASHHI        (0x00000084/4) /* Hash High address reg */
59 #define GEM_SPADDR1LO     (0x00000088/4) /* Specific addr 1 low reg */
60 #define GEM_SPADDR1HI     (0x0000008C/4) /* Specific addr 1 high reg */
61 #define GEM_SPADDR2LO     (0x00000090/4) /* Specific addr 2 low reg */
62 #define GEM_SPADDR2HI     (0x00000094/4) /* Specific addr 2 high reg */
63 #define GEM_SPADDR3LO     (0x00000098/4) /* Specific addr 3 low reg */
64 #define GEM_SPADDR3HI     (0x0000009C/4) /* Specific addr 3 high reg */
65 #define GEM_SPADDR4LO     (0x000000A0/4) /* Specific addr 4 low reg */
66 #define GEM_SPADDR4HI     (0x000000A4/4) /* Specific addr 4 high reg */
67 #define GEM_TIDMATCH1     (0x000000A8/4) /* Type ID1 Match reg */
68 #define GEM_TIDMATCH2     (0x000000AC/4) /* Type ID2 Match reg */
69 #define GEM_TIDMATCH3     (0x000000B0/4) /* Type ID3 Match reg */
70 #define GEM_TIDMATCH4     (0x000000B4/4) /* Type ID4 Match reg */
71 #define GEM_WOLAN         (0x000000B8/4) /* Wake on LAN reg */
72 #define GEM_IPGSTRETCH    (0x000000BC/4) /* IPG Stretch reg */
73 #define GEM_SVLAN         (0x000000C0/4) /* Stacked VLAN reg */
74 #define GEM_MODID         (0x000000FC/4) /* Module ID reg */
75 #define GEM_OCTTXLO       (0x00000100/4) /* Octects transmitted Low reg */
76 #define GEM_OCTTXHI       (0x00000104/4) /* Octects transmitted High reg */
77 #define GEM_TXCNT         (0x00000108/4) /* Error-free Frames transmitted */
78 #define GEM_TXBCNT        (0x0000010C/4) /* Error-free Broadcast Frames */
79 #define GEM_TXMCNT        (0x00000110/4) /* Error-free Multicast Frame */
80 #define GEM_TXPAUSECNT    (0x00000114/4) /* Pause Frames Transmitted */
81 #define GEM_TX64CNT       (0x00000118/4) /* Error-free 64 TX */
82 #define GEM_TX65CNT       (0x0000011C/4) /* Error-free 65-127 TX */
83 #define GEM_TX128CNT      (0x00000120/4) /* Error-free 128-255 TX */
84 #define GEM_TX256CNT      (0x00000124/4) /* Error-free 256-511 */
85 #define GEM_TX512CNT      (0x00000128/4) /* Error-free 512-1023 TX */
86 #define GEM_TX1024CNT     (0x0000012C/4) /* Error-free 1024-1518 TX */
87 #define GEM_TX1519CNT     (0x00000130/4) /* Error-free larger than 1519 TX */
88 #define GEM_TXURUNCNT     (0x00000134/4) /* TX under run error counter */
89 #define GEM_SINGLECOLLCNT (0x00000138/4) /* Single Collision Frames */
90 #define GEM_MULTCOLLCNT   (0x0000013C/4) /* Multiple Collision Frames */
91 #define GEM_EXCESSCOLLCNT (0x00000140/4) /* Excessive Collision Frames */
92 #define GEM_LATECOLLCNT   (0x00000144/4) /* Late Collision Frames */
93 #define GEM_DEFERTXCNT    (0x00000148/4) /* Deferred Transmission Frames */
94 #define GEM_CSENSECNT     (0x0000014C/4) /* Carrier Sense Error Counter */
95 #define GEM_OCTRXLO       (0x00000150/4) /* Octects Received register Low */
96 #define GEM_OCTRXHI       (0x00000154/4) /* Octects Received register High */
97 #define GEM_RXCNT         (0x00000158/4) /* Error-free Frames Received */
98 #define GEM_RXBROADCNT    (0x0000015C/4) /* Error-free Broadcast Frames RX */
99 #define GEM_RXMULTICNT    (0x00000160/4) /* Error-free Multicast Frames RX */
100 #define GEM_RXPAUSECNT    (0x00000164/4) /* Pause Frames Received Counter */
101 #define GEM_RX64CNT       (0x00000168/4) /* Error-free 64 byte Frames RX */
102 #define GEM_RX65CNT       (0x0000016C/4) /* Error-free 65-127B Frames RX */
103 #define GEM_RX128CNT      (0x00000170/4) /* Error-free 128-255B Frames RX */
104 #define GEM_RX256CNT      (0x00000174/4) /* Error-free 256-512B Frames RX */
105 #define GEM_RX512CNT      (0x00000178/4) /* Error-free 512-1023B Frames RX */
106 #define GEM_RX1024CNT     (0x0000017C/4) /* Error-free 1024-1518B Frames RX */
107 #define GEM_RX1519CNT     (0x00000180/4) /* Error-free 1519-max Frames RX */
108 #define GEM_RXUNDERCNT    (0x00000184/4) /* Undersize Frames Received */
109 #define GEM_RXOVERCNT     (0x00000188/4) /* Oversize Frames Received */
110 #define GEM_RXJABCNT      (0x0000018C/4) /* Jabbers Received Counter */
111 #define GEM_RXFCSCNT      (0x00000190/4) /* Frame Check seq. Error Counter */
112 #define GEM_RXLENERRCNT   (0x00000194/4) /* Length Field Error Counter */
113 #define GEM_RXSYMERRCNT   (0x00000198/4) /* Symbol Error Counter */
114 #define GEM_RXALIGNERRCNT (0x0000019C/4) /* Alignment Error Counter */
115 #define GEM_RXRSCERRCNT   (0x000001A0/4) /* Receive Resource Error Counter */
116 #define GEM_RXORUNCNT     (0x000001A4/4) /* Receive Overrun Counter */
117 #define GEM_RXIPCSERRCNT  (0x000001A8/4) /* IP header Checksum Error Counter */
118 #define GEM_RXTCPCCNT     (0x000001AC/4) /* TCP Checksum Error Counter */
119 #define GEM_RXUDPCCNT     (0x000001B0/4) /* UDP Checksum Error Counter */
120 
121 #define GEM_1588S         (0x000001D0/4) /* 1588 Timer Seconds */
122 #define GEM_1588NS        (0x000001D4/4) /* 1588 Timer Nanoseconds */
123 #define GEM_1588ADJ       (0x000001D8/4) /* 1588 Timer Adjust */
124 #define GEM_1588INC       (0x000001DC/4) /* 1588 Timer Increment */
125 #define GEM_PTPETXS       (0x000001E0/4) /* PTP Event Frame Transmitted (s) */
126 #define GEM_PTPETXNS      (0x000001E4/4) /* PTP Event Frame Transmitted (ns) */
127 #define GEM_PTPERXS       (0x000001E8/4) /* PTP Event Frame Received (s) */
128 #define GEM_PTPERXNS      (0x000001EC/4) /* PTP Event Frame Received (ns) */
129 #define GEM_PTPPTXS       (0x000001E0/4) /* PTP Peer Frame Transmitted (s) */
130 #define GEM_PTPPTXNS      (0x000001E4/4) /* PTP Peer Frame Transmitted (ns) */
131 #define GEM_PTPPRXS       (0x000001E8/4) /* PTP Peer Frame Received (s) */
132 #define GEM_PTPPRXNS      (0x000001EC/4) /* PTP Peer Frame Received (ns) */
133 
134 /* Design Configuration Registers */
135 #define GEM_DESCONF       (0x00000280/4)
136 #define GEM_DESCONF2      (0x00000284/4)
137 #define GEM_DESCONF3      (0x00000288/4)
138 #define GEM_DESCONF4      (0x0000028C/4)
139 #define GEM_DESCONF5      (0x00000290/4)
140 #define GEM_DESCONF6      (0x00000294/4)
141 #define GEM_DESCONF7      (0x00000298/4)
142 
143 /*****************************************/
144 #define GEM_NWCTRL_TXSTART     0x00000200 /* Transmit Enable */
145 #define GEM_NWCTRL_TXENA       0x00000008 /* Transmit Enable */
146 #define GEM_NWCTRL_RXENA       0x00000004 /* Receive Enable */
147 #define GEM_NWCTRL_LOCALLOOP   0x00000002 /* Local Loopback */
148 
149 #define GEM_NWCFG_STRIP_FCS    0x00020000 /* Strip FCS field */
150 #define GEM_NWCFG_LERR_DISC    0x00010000 /* Discard RX frames with len err */
151 #define GEM_NWCFG_BUFF_OFST_M  0x0000C000 /* Receive buffer offset mask */
152 #define GEM_NWCFG_BUFF_OFST_S  14         /* Receive buffer offset shift */
153 #define GEM_NWCFG_UCAST_HASH   0x00000080 /* accept unicast if hash match */
154 #define GEM_NWCFG_MCAST_HASH   0x00000040 /* accept multicast if hash match */
155 #define GEM_NWCFG_BCAST_REJ    0x00000020 /* Reject broadcast packets */
156 #define GEM_NWCFG_PROMISC      0x00000010 /* Accept all packets */
157 
158 #define GEM_DMACFG_RBUFSZ_M    0x00FF0000 /* DMA RX Buffer Size mask */
159 #define GEM_DMACFG_RBUFSZ_S    16         /* DMA RX Buffer Size shift */
160 #define GEM_DMACFG_RBUFSZ_MUL  64         /* DMA RX Buffer Size multiplier */
161 #define GEM_DMACFG_TXCSUM_OFFL 0x00000800 /* Transmit checksum offload */
162 
163 #define GEM_TXSTATUS_TXCMPL    0x00000020 /* Transmit Complete */
164 #define GEM_TXSTATUS_USED      0x00000001 /* sw owned descriptor encountered */
165 
166 #define GEM_RXSTATUS_FRMRCVD   0x00000002 /* Frame received */
167 #define GEM_RXSTATUS_NOBUF     0x00000001 /* Buffer unavailable */
168 
169 /* GEM_ISR GEM_IER GEM_IDR GEM_IMR */
170 #define GEM_INT_TXCMPL        0x00000080 /* Transmit Complete */
171 #define GEM_INT_TXUSED         0x00000008
172 #define GEM_INT_RXUSED         0x00000004
173 #define GEM_INT_RXCMPL        0x00000002
174 
175 #define GEM_PHYMNTNC_OP_R      0x20000000 /* read operation */
176 #define GEM_PHYMNTNC_OP_W      0x10000000 /* write operation */
177 #define GEM_PHYMNTNC_ADDR      0x0F800000 /* Address bits */
178 #define GEM_PHYMNTNC_ADDR_SHFT 23
179 #define GEM_PHYMNTNC_REG       0x007C0000 /* register bits */
180 #define GEM_PHYMNTNC_REG_SHIFT 18
181 
182 /* Marvell PHY definitions */
183 #define BOARD_PHY_ADDRESS    23 /* PHY address we will emulate a device at */
184 
185 #define PHY_REG_CONTROL      0
186 #define PHY_REG_STATUS       1
187 #define PHY_REG_PHYID1       2
188 #define PHY_REG_PHYID2       3
189 #define PHY_REG_ANEGADV      4
190 #define PHY_REG_LINKPABIL    5
191 #define PHY_REG_ANEGEXP      6
192 #define PHY_REG_NEXTP        7
193 #define PHY_REG_LINKPNEXTP   8
194 #define PHY_REG_100BTCTRL    9
195 #define PHY_REG_1000BTSTAT   10
196 #define PHY_REG_EXTSTAT      15
197 #define PHY_REG_PHYSPCFC_CTL 16
198 #define PHY_REG_PHYSPCFC_ST  17
199 #define PHY_REG_INT_EN       18
200 #define PHY_REG_INT_ST       19
201 #define PHY_REG_EXT_PHYSPCFC_CTL  20
202 #define PHY_REG_RXERR        21
203 #define PHY_REG_EACD         22
204 #define PHY_REG_LED          24
205 #define PHY_REG_LED_OVRD     25
206 #define PHY_REG_EXT_PHYSPCFC_CTL2 26
207 #define PHY_REG_EXT_PHYSPCFC_ST   27
208 #define PHY_REG_CABLE_DIAG   28
209 
210 #define PHY_REG_CONTROL_RST  0x8000
211 #define PHY_REG_CONTROL_LOOP 0x4000
212 #define PHY_REG_CONTROL_ANEG 0x1000
213 
214 #define PHY_REG_STATUS_LINK     0x0004
215 #define PHY_REG_STATUS_ANEGCMPL 0x0020
216 
217 #define PHY_REG_INT_ST_ANEGCMPL 0x0800
218 #define PHY_REG_INT_ST_LINKC    0x0400
219 #define PHY_REG_INT_ST_ENERGY   0x0010
220 
221 /***********************************************************************/
222 #define GEM_RX_REJECT                   (-1)
223 #define GEM_RX_PROMISCUOUS_ACCEPT       (-2)
224 #define GEM_RX_BROADCAST_ACCEPT         (-3)
225 #define GEM_RX_MULTICAST_HASH_ACCEPT    (-4)
226 #define GEM_RX_UNICAST_HASH_ACCEPT      (-5)
227 
228 #define GEM_RX_SAR_ACCEPT               0
229 
230 /***********************************************************************/
231 
232 #define DESC_1_USED 0x80000000
233 #define DESC_1_LENGTH 0x00001FFF
234 
235 #define DESC_1_TX_WRAP 0x40000000
236 #define DESC_1_TX_LAST 0x00008000
237 
238 #define DESC_0_RX_WRAP 0x00000002
239 #define DESC_0_RX_OWNERSHIP 0x00000001
240 
241 #define R_DESC_1_RX_SAR_SHIFT           25
242 #define R_DESC_1_RX_SAR_LENGTH          2
243 #define R_DESC_1_RX_SAR_MATCH           (1 << 27)
244 #define R_DESC_1_RX_UNICAST_HASH        (1 << 29)
245 #define R_DESC_1_RX_MULTICAST_HASH      (1 << 30)
246 #define R_DESC_1_RX_BROADCAST           (1 << 31)
247 
248 #define DESC_1_RX_SOF 0x00004000
249 #define DESC_1_RX_EOF 0x00008000
250 
251 static inline unsigned tx_desc_get_buffer(unsigned *desc)
252 {
253     return desc[0];
254 }
255 
256 static inline unsigned tx_desc_get_used(unsigned *desc)
257 {
258     return (desc[1] & DESC_1_USED) ? 1 : 0;
259 }
260 
261 static inline void tx_desc_set_used(unsigned *desc)
262 {
263     desc[1] |= DESC_1_USED;
264 }
265 
266 static inline unsigned tx_desc_get_wrap(unsigned *desc)
267 {
268     return (desc[1] & DESC_1_TX_WRAP) ? 1 : 0;
269 }
270 
271 static inline unsigned tx_desc_get_last(unsigned *desc)
272 {
273     return (desc[1] & DESC_1_TX_LAST) ? 1 : 0;
274 }
275 
276 static inline unsigned tx_desc_get_length(unsigned *desc)
277 {
278     return desc[1] & DESC_1_LENGTH;
279 }
280 
281 static inline void print_gem_tx_desc(unsigned *desc)
282 {
283     DB_PRINT("TXDESC:\n");
284     DB_PRINT("bufaddr: 0x%08x\n", *desc);
285     DB_PRINT("used_hw: %d\n", tx_desc_get_used(desc));
286     DB_PRINT("wrap:    %d\n", tx_desc_get_wrap(desc));
287     DB_PRINT("last:    %d\n", tx_desc_get_last(desc));
288     DB_PRINT("length:  %d\n", tx_desc_get_length(desc));
289 }
290 
291 static inline unsigned rx_desc_get_buffer(unsigned *desc)
292 {
293     return desc[0] & ~0x3UL;
294 }
295 
296 static inline unsigned rx_desc_get_wrap(unsigned *desc)
297 {
298     return desc[0] & DESC_0_RX_WRAP ? 1 : 0;
299 }
300 
301 static inline unsigned rx_desc_get_ownership(unsigned *desc)
302 {
303     return desc[0] & DESC_0_RX_OWNERSHIP ? 1 : 0;
304 }
305 
306 static inline void rx_desc_set_ownership(unsigned *desc)
307 {
308     desc[0] |= DESC_0_RX_OWNERSHIP;
309 }
310 
311 static inline void rx_desc_set_sof(unsigned *desc)
312 {
313     desc[1] |= DESC_1_RX_SOF;
314 }
315 
316 static inline void rx_desc_set_eof(unsigned *desc)
317 {
318     desc[1] |= DESC_1_RX_EOF;
319 }
320 
321 static inline void rx_desc_set_length(unsigned *desc, unsigned len)
322 {
323     desc[1] &= ~DESC_1_LENGTH;
324     desc[1] |= len;
325 }
326 
327 static inline void rx_desc_set_broadcast(unsigned *desc)
328 {
329     desc[1] |= R_DESC_1_RX_BROADCAST;
330 }
331 
332 static inline void rx_desc_set_unicast_hash(unsigned *desc)
333 {
334     desc[1] |= R_DESC_1_RX_UNICAST_HASH;
335 }
336 
337 static inline void rx_desc_set_multicast_hash(unsigned *desc)
338 {
339     desc[1] |= R_DESC_1_RX_MULTICAST_HASH;
340 }
341 
342 static inline void rx_desc_set_sar(unsigned *desc, int sar_idx)
343 {
344     desc[1] = deposit32(desc[1], R_DESC_1_RX_SAR_SHIFT, R_DESC_1_RX_SAR_LENGTH,
345                         sar_idx);
346     desc[1] |= R_DESC_1_RX_SAR_MATCH;
347 }
348 
349 /* The broadcast MAC address: 0xFFFFFFFFFFFF */
350 static const uint8_t broadcast_addr[] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
351 
352 /*
353  * gem_init_register_masks:
354  * One time initialization.
355  * Set masks to identify which register bits have magical clear properties
356  */
357 static void gem_init_register_masks(CadenceGEMState *s)
358 {
359     /* Mask of register bits which are read only */
360     memset(&s->regs_ro[0], 0, sizeof(s->regs_ro));
361     s->regs_ro[GEM_NWCTRL]   = 0xFFF80000;
362     s->regs_ro[GEM_NWSTATUS] = 0xFFFFFFFF;
363     s->regs_ro[GEM_DMACFG]   = 0xFE00F000;
364     s->regs_ro[GEM_TXSTATUS] = 0xFFFFFE08;
365     s->regs_ro[GEM_RXQBASE]  = 0x00000003;
366     s->regs_ro[GEM_TXQBASE]  = 0x00000003;
367     s->regs_ro[GEM_RXSTATUS] = 0xFFFFFFF0;
368     s->regs_ro[GEM_ISR]      = 0xFFFFFFFF;
369     s->regs_ro[GEM_IMR]      = 0xFFFFFFFF;
370     s->regs_ro[GEM_MODID]    = 0xFFFFFFFF;
371 
372     /* Mask of register bits which are clear on read */
373     memset(&s->regs_rtc[0], 0, sizeof(s->regs_rtc));
374     s->regs_rtc[GEM_ISR]      = 0xFFFFFFFF;
375 
376     /* Mask of register bits which are write 1 to clear */
377     memset(&s->regs_w1c[0], 0, sizeof(s->regs_w1c));
378     s->regs_w1c[GEM_TXSTATUS] = 0x000001F7;
379     s->regs_w1c[GEM_RXSTATUS] = 0x0000000F;
380 
381     /* Mask of register bits which are write only */
382     memset(&s->regs_wo[0], 0, sizeof(s->regs_wo));
383     s->regs_wo[GEM_NWCTRL]   = 0x00073E60;
384     s->regs_wo[GEM_IER]      = 0x07FFFFFF;
385     s->regs_wo[GEM_IDR]      = 0x07FFFFFF;
386 }
387 
388 /*
389  * phy_update_link:
390  * Make the emulated PHY link state match the QEMU "interface" state.
391  */
392 static void phy_update_link(CadenceGEMState *s)
393 {
394     DB_PRINT("down %d\n", qemu_get_queue(s->nic)->link_down);
395 
396     /* Autonegotiation status mirrors link status.  */
397     if (qemu_get_queue(s->nic)->link_down) {
398         s->phy_regs[PHY_REG_STATUS] &= ~(PHY_REG_STATUS_ANEGCMPL |
399                                          PHY_REG_STATUS_LINK);
400         s->phy_regs[PHY_REG_INT_ST] |= PHY_REG_INT_ST_LINKC;
401     } else {
402         s->phy_regs[PHY_REG_STATUS] |= (PHY_REG_STATUS_ANEGCMPL |
403                                          PHY_REG_STATUS_LINK);
404         s->phy_regs[PHY_REG_INT_ST] |= (PHY_REG_INT_ST_LINKC |
405                                         PHY_REG_INT_ST_ANEGCMPL |
406                                         PHY_REG_INT_ST_ENERGY);
407     }
408 }
409 
410 static int gem_can_receive(NetClientState *nc)
411 {
412     CadenceGEMState *s;
413 
414     s = qemu_get_nic_opaque(nc);
415 
416     /* Do nothing if receive is not enabled. */
417     if (!(s->regs[GEM_NWCTRL] & GEM_NWCTRL_RXENA)) {
418         if (s->can_rx_state != 1) {
419             s->can_rx_state = 1;
420             DB_PRINT("can't receive - no enable\n");
421         }
422         return 0;
423     }
424 
425     if (rx_desc_get_ownership(s->rx_desc) == 1) {
426         if (s->can_rx_state != 2) {
427             s->can_rx_state = 2;
428             DB_PRINT("can't receive - busy buffer descriptor 0x%x\n",
429                      s->rx_desc_addr);
430         }
431         return 0;
432     }
433 
434     if (s->can_rx_state != 0) {
435         s->can_rx_state = 0;
436         DB_PRINT("can receive 0x%x\n", s->rx_desc_addr);
437     }
438     return 1;
439 }
440 
441 /*
442  * gem_update_int_status:
443  * Raise or lower interrupt based on current status.
444  */
445 static void gem_update_int_status(CadenceGEMState *s)
446 {
447     if (s->regs[GEM_ISR]) {
448         DB_PRINT("asserting int. (0x%08x)\n", s->regs[GEM_ISR]);
449         qemu_set_irq(s->irq, 1);
450     }
451 }
452 
453 /*
454  * gem_receive_updatestats:
455  * Increment receive statistics.
456  */
457 static void gem_receive_updatestats(CadenceGEMState *s, const uint8_t *packet,
458                                     unsigned bytes)
459 {
460     uint64_t octets;
461 
462     /* Total octets (bytes) received */
463     octets = ((uint64_t)(s->regs[GEM_OCTRXLO]) << 32) |
464              s->regs[GEM_OCTRXHI];
465     octets += bytes;
466     s->regs[GEM_OCTRXLO] = octets >> 32;
467     s->regs[GEM_OCTRXHI] = octets;
468 
469     /* Error-free Frames received */
470     s->regs[GEM_RXCNT]++;
471 
472     /* Error-free Broadcast Frames counter */
473     if (!memcmp(packet, broadcast_addr, 6)) {
474         s->regs[GEM_RXBROADCNT]++;
475     }
476 
477     /* Error-free Multicast Frames counter */
478     if (packet[0] == 0x01) {
479         s->regs[GEM_RXMULTICNT]++;
480     }
481 
482     if (bytes <= 64) {
483         s->regs[GEM_RX64CNT]++;
484     } else if (bytes <= 127) {
485         s->regs[GEM_RX65CNT]++;
486     } else if (bytes <= 255) {
487         s->regs[GEM_RX128CNT]++;
488     } else if (bytes <= 511) {
489         s->regs[GEM_RX256CNT]++;
490     } else if (bytes <= 1023) {
491         s->regs[GEM_RX512CNT]++;
492     } else if (bytes <= 1518) {
493         s->regs[GEM_RX1024CNT]++;
494     } else {
495         s->regs[GEM_RX1519CNT]++;
496     }
497 }
498 
499 /*
500  * Get the MAC Address bit from the specified position
501  */
502 static unsigned get_bit(const uint8_t *mac, unsigned bit)
503 {
504     unsigned byte;
505 
506     byte = mac[bit / 8];
507     byte >>= (bit & 0x7);
508     byte &= 1;
509 
510     return byte;
511 }
512 
513 /*
514  * Calculate a GEM MAC Address hash index
515  */
516 static unsigned calc_mac_hash(const uint8_t *mac)
517 {
518     int index_bit, mac_bit;
519     unsigned hash_index;
520 
521     hash_index = 0;
522     mac_bit = 5;
523     for (index_bit = 5; index_bit >= 0; index_bit--) {
524         hash_index |= (get_bit(mac,  mac_bit) ^
525                                get_bit(mac, mac_bit + 6) ^
526                                get_bit(mac, mac_bit + 12) ^
527                                get_bit(mac, mac_bit + 18) ^
528                                get_bit(mac, mac_bit + 24) ^
529                                get_bit(mac, mac_bit + 30) ^
530                                get_bit(mac, mac_bit + 36) ^
531                                get_bit(mac, mac_bit + 42)) << index_bit;
532         mac_bit--;
533     }
534 
535     return hash_index;
536 }
537 
538 /*
539  * gem_mac_address_filter:
540  * Accept or reject this destination address?
541  * Returns:
542  * GEM_RX_REJECT: reject
543  * >= 0: Specific address accept (which matched SAR is returned)
544  * others for various other modes of accept:
545  * GEM_RM_PROMISCUOUS_ACCEPT, GEM_RX_BROADCAST_ACCEPT,
546  * GEM_RX_MULTICAST_HASH_ACCEPT or GEM_RX_UNICAST_HASH_ACCEPT
547  */
548 static int gem_mac_address_filter(CadenceGEMState *s, const uint8_t *packet)
549 {
550     uint8_t *gem_spaddr;
551     int i;
552 
553     /* Promiscuous mode? */
554     if (s->regs[GEM_NWCFG] & GEM_NWCFG_PROMISC) {
555         return GEM_RX_PROMISCUOUS_ACCEPT;
556     }
557 
558     if (!memcmp(packet, broadcast_addr, 6)) {
559         /* Reject broadcast packets? */
560         if (s->regs[GEM_NWCFG] & GEM_NWCFG_BCAST_REJ) {
561             return GEM_RX_REJECT;
562         }
563         return GEM_RX_BROADCAST_ACCEPT;
564     }
565 
566     /* Accept packets -w- hash match? */
567     if ((packet[0] == 0x01 && (s->regs[GEM_NWCFG] & GEM_NWCFG_MCAST_HASH)) ||
568         (packet[0] != 0x01 && (s->regs[GEM_NWCFG] & GEM_NWCFG_UCAST_HASH))) {
569         unsigned hash_index;
570 
571         hash_index = calc_mac_hash(packet);
572         if (hash_index < 32) {
573             if (s->regs[GEM_HASHLO] & (1<<hash_index)) {
574                 return packet[0] == 0x01 ? GEM_RX_MULTICAST_HASH_ACCEPT :
575                                            GEM_RX_UNICAST_HASH_ACCEPT;
576             }
577         } else {
578             hash_index -= 32;
579             if (s->regs[GEM_HASHHI] & (1<<hash_index)) {
580                 return packet[0] == 0x01 ? GEM_RX_MULTICAST_HASH_ACCEPT :
581                                            GEM_RX_UNICAST_HASH_ACCEPT;
582             }
583         }
584     }
585 
586     /* Check all 4 specific addresses */
587     gem_spaddr = (uint8_t *)&(s->regs[GEM_SPADDR1LO]);
588     for (i = 3; i >= 0; i--) {
589         if (s->sar_active[i] && !memcmp(packet, gem_spaddr + 8 * i, 6)) {
590             return GEM_RX_SAR_ACCEPT + i;
591         }
592     }
593 
594     /* No address match; reject the packet */
595     return GEM_RX_REJECT;
596 }
597 
598 static void gem_get_rx_desc(CadenceGEMState *s)
599 {
600     DB_PRINT("read descriptor 0x%x\n", (unsigned)s->rx_desc_addr);
601     /* read current descriptor */
602     cpu_physical_memory_read(s->rx_desc_addr,
603                              (uint8_t *)s->rx_desc, sizeof(s->rx_desc));
604 
605     /* Descriptor owned by software ? */
606     if (rx_desc_get_ownership(s->rx_desc) == 1) {
607         DB_PRINT("descriptor 0x%x owned by sw.\n",
608                  (unsigned)s->rx_desc_addr);
609         s->regs[GEM_RXSTATUS] |= GEM_RXSTATUS_NOBUF;
610         s->regs[GEM_ISR] |= GEM_INT_RXUSED & ~(s->regs[GEM_IMR]);
611         /* Handle interrupt consequences */
612         gem_update_int_status(s);
613     }
614 }
615 
616 /*
617  * gem_receive:
618  * Fit a packet handed to us by QEMU into the receive descriptor ring.
619  */
620 static ssize_t gem_receive(NetClientState *nc, const uint8_t *buf, size_t size)
621 {
622     CadenceGEMState *s;
623     unsigned   rxbufsize, bytes_to_copy;
624     unsigned   rxbuf_offset;
625     uint8_t    rxbuf[2048];
626     uint8_t   *rxbuf_ptr;
627     bool first_desc = true;
628     int maf;
629 
630     s = qemu_get_nic_opaque(nc);
631 
632     /* Is this destination MAC address "for us" ? */
633     maf = gem_mac_address_filter(s, buf);
634     if (maf == GEM_RX_REJECT) {
635         return -1;
636     }
637 
638     /* Discard packets with receive length error enabled ? */
639     if (s->regs[GEM_NWCFG] & GEM_NWCFG_LERR_DISC) {
640         unsigned type_len;
641 
642         /* Fish the ethertype / length field out of the RX packet */
643         type_len = buf[12] << 8 | buf[13];
644         /* It is a length field, not an ethertype */
645         if (type_len < 0x600) {
646             if (size < type_len) {
647                 /* discard */
648                 return -1;
649             }
650         }
651     }
652 
653     /*
654      * Determine configured receive buffer offset (probably 0)
655      */
656     rxbuf_offset = (s->regs[GEM_NWCFG] & GEM_NWCFG_BUFF_OFST_M) >>
657                    GEM_NWCFG_BUFF_OFST_S;
658 
659     /* The configure size of each receive buffer.  Determines how many
660      * buffers needed to hold this packet.
661      */
662     rxbufsize = ((s->regs[GEM_DMACFG] & GEM_DMACFG_RBUFSZ_M) >>
663                  GEM_DMACFG_RBUFSZ_S) * GEM_DMACFG_RBUFSZ_MUL;
664     bytes_to_copy = size;
665 
666     /* Pad to minimum length. Assume FCS field is stripped, logic
667      * below will increment it to the real minimum of 64 when
668      * not FCS stripping
669      */
670     if (size < 60) {
671         size = 60;
672     }
673 
674     /* Strip of FCS field ? (usually yes) */
675     if (s->regs[GEM_NWCFG] & GEM_NWCFG_STRIP_FCS) {
676         rxbuf_ptr = (void *)buf;
677     } else {
678         unsigned crc_val;
679 
680         /* The application wants the FCS field, which QEMU does not provide.
681          * We must try and calculate one.
682          */
683 
684         memcpy(rxbuf, buf, size);
685         memset(rxbuf + size, 0, sizeof(rxbuf) - size);
686         rxbuf_ptr = rxbuf;
687         crc_val = cpu_to_le32(crc32(0, rxbuf, MAX(size, 60)));
688         memcpy(rxbuf + size, &crc_val, sizeof(crc_val));
689 
690         bytes_to_copy += 4;
691         size += 4;
692     }
693 
694     DB_PRINT("config bufsize: %d packet size: %ld\n", rxbufsize, size);
695 
696     while (bytes_to_copy) {
697         /* Do nothing if receive is not enabled. */
698         if (!gem_can_receive(nc)) {
699             assert(!first_desc);
700             return -1;
701         }
702 
703         DB_PRINT("copy %d bytes to 0x%x\n", MIN(bytes_to_copy, rxbufsize),
704                 rx_desc_get_buffer(s->rx_desc));
705 
706         /* Copy packet data to emulated DMA buffer */
707         cpu_physical_memory_write(rx_desc_get_buffer(s->rx_desc) + rxbuf_offset,
708                                   rxbuf_ptr, MIN(bytes_to_copy, rxbufsize));
709         rxbuf_ptr += MIN(bytes_to_copy, rxbufsize);
710         bytes_to_copy -= MIN(bytes_to_copy, rxbufsize);
711 
712         /* Update the descriptor.  */
713         if (first_desc) {
714             rx_desc_set_sof(s->rx_desc);
715             first_desc = false;
716         }
717         if (bytes_to_copy == 0) {
718             rx_desc_set_eof(s->rx_desc);
719             rx_desc_set_length(s->rx_desc, size);
720         }
721         rx_desc_set_ownership(s->rx_desc);
722 
723         switch (maf) {
724         case GEM_RX_PROMISCUOUS_ACCEPT:
725             break;
726         case GEM_RX_BROADCAST_ACCEPT:
727             rx_desc_set_broadcast(s->rx_desc);
728             break;
729         case GEM_RX_UNICAST_HASH_ACCEPT:
730             rx_desc_set_unicast_hash(s->rx_desc);
731             break;
732         case GEM_RX_MULTICAST_HASH_ACCEPT:
733             rx_desc_set_multicast_hash(s->rx_desc);
734             break;
735         case GEM_RX_REJECT:
736             abort();
737         default: /* SAR */
738             rx_desc_set_sar(s->rx_desc, maf);
739         }
740 
741         /* Descriptor write-back.  */
742         cpu_physical_memory_write(s->rx_desc_addr,
743                                   (uint8_t *)s->rx_desc, sizeof(s->rx_desc));
744 
745         /* Next descriptor */
746         if (rx_desc_get_wrap(s->rx_desc)) {
747             DB_PRINT("wrapping RX descriptor list\n");
748             s->rx_desc_addr = s->regs[GEM_RXQBASE];
749         } else {
750             DB_PRINT("incrementing RX descriptor list\n");
751             s->rx_desc_addr += 8;
752         }
753         gem_get_rx_desc(s);
754     }
755 
756     /* Count it */
757     gem_receive_updatestats(s, buf, size);
758 
759     s->regs[GEM_RXSTATUS] |= GEM_RXSTATUS_FRMRCVD;
760     s->regs[GEM_ISR] |= GEM_INT_RXCMPL & ~(s->regs[GEM_IMR]);
761 
762     /* Handle interrupt consequences */
763     gem_update_int_status(s);
764 
765     return size;
766 }
767 
768 /*
769  * gem_transmit_updatestats:
770  * Increment transmit statistics.
771  */
772 static void gem_transmit_updatestats(CadenceGEMState *s, const uint8_t *packet,
773                                      unsigned bytes)
774 {
775     uint64_t octets;
776 
777     /* Total octets (bytes) transmitted */
778     octets = ((uint64_t)(s->regs[GEM_OCTTXLO]) << 32) |
779              s->regs[GEM_OCTTXHI];
780     octets += bytes;
781     s->regs[GEM_OCTTXLO] = octets >> 32;
782     s->regs[GEM_OCTTXHI] = octets;
783 
784     /* Error-free Frames transmitted */
785     s->regs[GEM_TXCNT]++;
786 
787     /* Error-free Broadcast Frames counter */
788     if (!memcmp(packet, broadcast_addr, 6)) {
789         s->regs[GEM_TXBCNT]++;
790     }
791 
792     /* Error-free Multicast Frames counter */
793     if (packet[0] == 0x01) {
794         s->regs[GEM_TXMCNT]++;
795     }
796 
797     if (bytes <= 64) {
798         s->regs[GEM_TX64CNT]++;
799     } else if (bytes <= 127) {
800         s->regs[GEM_TX65CNT]++;
801     } else if (bytes <= 255) {
802         s->regs[GEM_TX128CNT]++;
803     } else if (bytes <= 511) {
804         s->regs[GEM_TX256CNT]++;
805     } else if (bytes <= 1023) {
806         s->regs[GEM_TX512CNT]++;
807     } else if (bytes <= 1518) {
808         s->regs[GEM_TX1024CNT]++;
809     } else {
810         s->regs[GEM_TX1519CNT]++;
811     }
812 }
813 
814 /*
815  * gem_transmit:
816  * Fish packets out of the descriptor ring and feed them to QEMU
817  */
818 static void gem_transmit(CadenceGEMState *s)
819 {
820     unsigned    desc[2];
821     hwaddr packet_desc_addr;
822     uint8_t     tx_packet[2048];
823     uint8_t     *p;
824     unsigned    total_bytes;
825 
826     /* Do nothing if transmit is not enabled. */
827     if (!(s->regs[GEM_NWCTRL] & GEM_NWCTRL_TXENA)) {
828         return;
829     }
830 
831     DB_PRINT("\n");
832 
833     /* The packet we will hand off to QEMU.
834      * Packets scattered across multiple descriptors are gathered to this
835      * one contiguous buffer first.
836      */
837     p = tx_packet;
838     total_bytes = 0;
839 
840     /* read current descriptor */
841     packet_desc_addr = s->tx_desc_addr;
842 
843     DB_PRINT("read descriptor 0x%" HWADDR_PRIx "\n", packet_desc_addr);
844     cpu_physical_memory_read(packet_desc_addr,
845                              (uint8_t *)desc, sizeof(desc));
846     /* Handle all descriptors owned by hardware */
847     while (tx_desc_get_used(desc) == 0) {
848 
849         /* Do nothing if transmit is not enabled. */
850         if (!(s->regs[GEM_NWCTRL] & GEM_NWCTRL_TXENA)) {
851             return;
852         }
853         print_gem_tx_desc(desc);
854 
855         /* The real hardware would eat this (and possibly crash).
856          * For QEMU let's lend a helping hand.
857          */
858         if ((tx_desc_get_buffer(desc) == 0) ||
859             (tx_desc_get_length(desc) == 0)) {
860             DB_PRINT("Invalid TX descriptor @ 0x%x\n",
861                      (unsigned)packet_desc_addr);
862             break;
863         }
864 
865         /* Gather this fragment of the packet from "dma memory" to our contig.
866          * buffer.
867          */
868         cpu_physical_memory_read(tx_desc_get_buffer(desc), p,
869                                  tx_desc_get_length(desc));
870         p += tx_desc_get_length(desc);
871         total_bytes += tx_desc_get_length(desc);
872 
873         /* Last descriptor for this packet; hand the whole thing off */
874         if (tx_desc_get_last(desc)) {
875             unsigned    desc_first[2];
876 
877             /* Modify the 1st descriptor of this packet to be owned by
878              * the processor.
879              */
880             cpu_physical_memory_read(s->tx_desc_addr, (uint8_t *)desc_first,
881                                      sizeof(desc_first));
882             tx_desc_set_used(desc_first);
883             cpu_physical_memory_write(s->tx_desc_addr, (uint8_t *)desc_first,
884                                       sizeof(desc_first));
885             /* Advance the hardware current descriptor past this packet */
886             if (tx_desc_get_wrap(desc)) {
887                 s->tx_desc_addr = s->regs[GEM_TXQBASE];
888             } else {
889                 s->tx_desc_addr = packet_desc_addr + 8;
890             }
891             DB_PRINT("TX descriptor next: 0x%08x\n", s->tx_desc_addr);
892 
893             s->regs[GEM_TXSTATUS] |= GEM_TXSTATUS_TXCMPL;
894             s->regs[GEM_ISR] |= GEM_INT_TXCMPL & ~(s->regs[GEM_IMR]);
895 
896             /* Handle interrupt consequences */
897             gem_update_int_status(s);
898 
899             /* Is checksum offload enabled? */
900             if (s->regs[GEM_DMACFG] & GEM_DMACFG_TXCSUM_OFFL) {
901                 net_checksum_calculate(tx_packet, total_bytes);
902             }
903 
904             /* Update MAC statistics */
905             gem_transmit_updatestats(s, tx_packet, total_bytes);
906 
907             /* Send the packet somewhere */
908             if (s->phy_loop || (s->regs[GEM_NWCTRL] & GEM_NWCTRL_LOCALLOOP)) {
909                 gem_receive(qemu_get_queue(s->nic), tx_packet, total_bytes);
910             } else {
911                 qemu_send_packet(qemu_get_queue(s->nic), tx_packet,
912                                  total_bytes);
913             }
914 
915             /* Prepare for next packet */
916             p = tx_packet;
917             total_bytes = 0;
918         }
919 
920         /* read next descriptor */
921         if (tx_desc_get_wrap(desc)) {
922             packet_desc_addr = s->regs[GEM_TXQBASE];
923         } else {
924             packet_desc_addr += 8;
925         }
926         DB_PRINT("read descriptor 0x%" HWADDR_PRIx "\n", packet_desc_addr);
927         cpu_physical_memory_read(packet_desc_addr,
928                                  (uint8_t *)desc, sizeof(desc));
929     }
930 
931     if (tx_desc_get_used(desc)) {
932         s->regs[GEM_TXSTATUS] |= GEM_TXSTATUS_USED;
933         s->regs[GEM_ISR] |= GEM_INT_TXUSED & ~(s->regs[GEM_IMR]);
934         gem_update_int_status(s);
935     }
936 }
937 
938 static void gem_phy_reset(CadenceGEMState *s)
939 {
940     memset(&s->phy_regs[0], 0, sizeof(s->phy_regs));
941     s->phy_regs[PHY_REG_CONTROL] = 0x1140;
942     s->phy_regs[PHY_REG_STATUS] = 0x7969;
943     s->phy_regs[PHY_REG_PHYID1] = 0x0141;
944     s->phy_regs[PHY_REG_PHYID2] = 0x0CC2;
945     s->phy_regs[PHY_REG_ANEGADV] = 0x01E1;
946     s->phy_regs[PHY_REG_LINKPABIL] = 0xCDE1;
947     s->phy_regs[PHY_REG_ANEGEXP] = 0x000F;
948     s->phy_regs[PHY_REG_NEXTP] = 0x2001;
949     s->phy_regs[PHY_REG_LINKPNEXTP] = 0x40E6;
950     s->phy_regs[PHY_REG_100BTCTRL] = 0x0300;
951     s->phy_regs[PHY_REG_1000BTSTAT] = 0x7C00;
952     s->phy_regs[PHY_REG_EXTSTAT] = 0x3000;
953     s->phy_regs[PHY_REG_PHYSPCFC_CTL] = 0x0078;
954     s->phy_regs[PHY_REG_PHYSPCFC_ST] = 0x7C00;
955     s->phy_regs[PHY_REG_EXT_PHYSPCFC_CTL] = 0x0C60;
956     s->phy_regs[PHY_REG_LED] = 0x4100;
957     s->phy_regs[PHY_REG_EXT_PHYSPCFC_CTL2] = 0x000A;
958     s->phy_regs[PHY_REG_EXT_PHYSPCFC_ST] = 0x848B;
959 
960     phy_update_link(s);
961 }
962 
963 static void gem_reset(DeviceState *d)
964 {
965     int i;
966     CadenceGEMState *s = CADENCE_GEM(d);
967     const uint8_t *a;
968 
969     DB_PRINT("\n");
970 
971     /* Set post reset register values */
972     memset(&s->regs[0], 0, sizeof(s->regs));
973     s->regs[GEM_NWCFG] = 0x00080000;
974     s->regs[GEM_NWSTATUS] = 0x00000006;
975     s->regs[GEM_DMACFG] = 0x00020784;
976     s->regs[GEM_IMR] = 0x07ffffff;
977     s->regs[GEM_TXPAUSE] = 0x0000ffff;
978     s->regs[GEM_TXPARTIALSF] = 0x000003ff;
979     s->regs[GEM_RXPARTIALSF] = 0x000003ff;
980     s->regs[GEM_MODID] = 0x00020118;
981     s->regs[GEM_DESCONF] = 0x02500111;
982     s->regs[GEM_DESCONF2] = 0x2ab13fff;
983     s->regs[GEM_DESCONF5] = 0x002f2145;
984     s->regs[GEM_DESCONF6] = 0x00000200;
985 
986     /* Set MAC address */
987     a = &s->conf.macaddr.a[0];
988     s->regs[GEM_SPADDR1LO] = a[0] | (a[1] << 8) | (a[2] << 16) | (a[3] << 24);
989     s->regs[GEM_SPADDR1HI] = a[4] | (a[5] << 8);
990 
991     for (i = 0; i < 4; i++) {
992         s->sar_active[i] = false;
993     }
994 
995     gem_phy_reset(s);
996 
997     gem_update_int_status(s);
998 }
999 
1000 static uint16_t gem_phy_read(CadenceGEMState *s, unsigned reg_num)
1001 {
1002     DB_PRINT("reg: %d value: 0x%04x\n", reg_num, s->phy_regs[reg_num]);
1003     return s->phy_regs[reg_num];
1004 }
1005 
1006 static void gem_phy_write(CadenceGEMState *s, unsigned reg_num, uint16_t val)
1007 {
1008     DB_PRINT("reg: %d value: 0x%04x\n", reg_num, val);
1009 
1010     switch (reg_num) {
1011     case PHY_REG_CONTROL:
1012         if (val & PHY_REG_CONTROL_RST) {
1013             /* Phy reset */
1014             gem_phy_reset(s);
1015             val &= ~(PHY_REG_CONTROL_RST | PHY_REG_CONTROL_LOOP);
1016             s->phy_loop = 0;
1017         }
1018         if (val & PHY_REG_CONTROL_ANEG) {
1019             /* Complete autonegotiation immediately */
1020             val &= ~PHY_REG_CONTROL_ANEG;
1021             s->phy_regs[PHY_REG_STATUS] |= PHY_REG_STATUS_ANEGCMPL;
1022         }
1023         if (val & PHY_REG_CONTROL_LOOP) {
1024             DB_PRINT("PHY placed in loopback\n");
1025             s->phy_loop = 1;
1026         } else {
1027             s->phy_loop = 0;
1028         }
1029         break;
1030     }
1031     s->phy_regs[reg_num] = val;
1032 }
1033 
1034 /*
1035  * gem_read32:
1036  * Read a GEM register.
1037  */
1038 static uint64_t gem_read(void *opaque, hwaddr offset, unsigned size)
1039 {
1040     CadenceGEMState *s;
1041     uint32_t retval;
1042 
1043     s = (CadenceGEMState *)opaque;
1044 
1045     offset >>= 2;
1046     retval = s->regs[offset];
1047 
1048     DB_PRINT("offset: 0x%04x read: 0x%08x\n", (unsigned)offset*4, retval);
1049 
1050     switch (offset) {
1051     case GEM_ISR:
1052         DB_PRINT("lowering irq on ISR read\n");
1053         qemu_set_irq(s->irq, 0);
1054         break;
1055     case GEM_PHYMNTNC:
1056         if (retval & GEM_PHYMNTNC_OP_R) {
1057             uint32_t phy_addr, reg_num;
1058 
1059             phy_addr = (retval & GEM_PHYMNTNC_ADDR) >> GEM_PHYMNTNC_ADDR_SHFT;
1060             if (phy_addr == BOARD_PHY_ADDRESS || phy_addr == 0) {
1061                 reg_num = (retval & GEM_PHYMNTNC_REG) >> GEM_PHYMNTNC_REG_SHIFT;
1062                 retval &= 0xFFFF0000;
1063                 retval |= gem_phy_read(s, reg_num);
1064             } else {
1065                 retval |= 0xFFFF; /* No device at this address */
1066             }
1067         }
1068         break;
1069     }
1070 
1071     /* Squash read to clear bits */
1072     s->regs[offset] &= ~(s->regs_rtc[offset]);
1073 
1074     /* Do not provide write only bits */
1075     retval &= ~(s->regs_wo[offset]);
1076 
1077     DB_PRINT("0x%08x\n", retval);
1078     return retval;
1079 }
1080 
1081 /*
1082  * gem_write32:
1083  * Write a GEM register.
1084  */
1085 static void gem_write(void *opaque, hwaddr offset, uint64_t val,
1086         unsigned size)
1087 {
1088     CadenceGEMState *s = (CadenceGEMState *)opaque;
1089     uint32_t readonly;
1090 
1091     DB_PRINT("offset: 0x%04x write: 0x%08x ", (unsigned)offset, (unsigned)val);
1092     offset >>= 2;
1093 
1094     /* Squash bits which are read only in write value */
1095     val &= ~(s->regs_ro[offset]);
1096     /* Preserve (only) bits which are read only and wtc in register */
1097     readonly = s->regs[offset] & (s->regs_ro[offset] | s->regs_w1c[offset]);
1098 
1099     /* Copy register write to backing store */
1100     s->regs[offset] = (val & ~s->regs_w1c[offset]) | readonly;
1101 
1102     /* do w1c */
1103     s->regs[offset] &= ~(s->regs_w1c[offset] & val);
1104 
1105     /* Handle register write side effects */
1106     switch (offset) {
1107     case GEM_NWCTRL:
1108         if (val & GEM_NWCTRL_RXENA) {
1109             gem_get_rx_desc(s);
1110         }
1111         if (val & GEM_NWCTRL_TXSTART) {
1112             gem_transmit(s);
1113         }
1114         if (!(val & GEM_NWCTRL_TXENA)) {
1115             /* Reset to start of Q when transmit disabled. */
1116             s->tx_desc_addr = s->regs[GEM_TXQBASE];
1117         }
1118         if (gem_can_receive(qemu_get_queue(s->nic))) {
1119             qemu_flush_queued_packets(qemu_get_queue(s->nic));
1120         }
1121         break;
1122 
1123     case GEM_TXSTATUS:
1124         gem_update_int_status(s);
1125         break;
1126     case GEM_RXQBASE:
1127         s->rx_desc_addr = val;
1128         break;
1129     case GEM_TXQBASE:
1130         s->tx_desc_addr = val;
1131         break;
1132     case GEM_RXSTATUS:
1133         gem_update_int_status(s);
1134         break;
1135     case GEM_IER:
1136         s->regs[GEM_IMR] &= ~val;
1137         gem_update_int_status(s);
1138         break;
1139     case GEM_IDR:
1140         s->regs[GEM_IMR] |= val;
1141         gem_update_int_status(s);
1142         break;
1143     case GEM_SPADDR1LO:
1144     case GEM_SPADDR2LO:
1145     case GEM_SPADDR3LO:
1146     case GEM_SPADDR4LO:
1147         s->sar_active[(offset - GEM_SPADDR1LO) / 2] = false;
1148         break;
1149     case GEM_SPADDR1HI:
1150     case GEM_SPADDR2HI:
1151     case GEM_SPADDR3HI:
1152     case GEM_SPADDR4HI:
1153         s->sar_active[(offset - GEM_SPADDR1HI) / 2] = true;
1154         break;
1155     case GEM_PHYMNTNC:
1156         if (val & GEM_PHYMNTNC_OP_W) {
1157             uint32_t phy_addr, reg_num;
1158 
1159             phy_addr = (val & GEM_PHYMNTNC_ADDR) >> GEM_PHYMNTNC_ADDR_SHFT;
1160             if (phy_addr == BOARD_PHY_ADDRESS || phy_addr == 0) {
1161                 reg_num = (val & GEM_PHYMNTNC_REG) >> GEM_PHYMNTNC_REG_SHIFT;
1162                 gem_phy_write(s, reg_num, val);
1163             }
1164         }
1165         break;
1166     }
1167 
1168     DB_PRINT("newval: 0x%08x\n", s->regs[offset]);
1169 }
1170 
1171 static const MemoryRegionOps gem_ops = {
1172     .read = gem_read,
1173     .write = gem_write,
1174     .endianness = DEVICE_LITTLE_ENDIAN,
1175 };
1176 
1177 static void gem_set_link(NetClientState *nc)
1178 {
1179     DB_PRINT("\n");
1180     phy_update_link(qemu_get_nic_opaque(nc));
1181 }
1182 
1183 static NetClientInfo net_gem_info = {
1184     .type = NET_CLIENT_OPTIONS_KIND_NIC,
1185     .size = sizeof(NICState),
1186     .can_receive = gem_can_receive,
1187     .receive = gem_receive,
1188     .link_status_changed = gem_set_link,
1189 };
1190 
1191 static int gem_init(SysBusDevice *sbd)
1192 {
1193     DeviceState *dev = DEVICE(sbd);
1194     CadenceGEMState *s = CADENCE_GEM(dev);
1195 
1196     DB_PRINT("\n");
1197 
1198     gem_init_register_masks(s);
1199     memory_region_init_io(&s->iomem, OBJECT(s), &gem_ops, s,
1200                           "enet", sizeof(s->regs));
1201     sysbus_init_mmio(sbd, &s->iomem);
1202     sysbus_init_irq(sbd, &s->irq);
1203     qemu_macaddr_default_if_unset(&s->conf.macaddr);
1204 
1205     s->nic = qemu_new_nic(&net_gem_info, &s->conf,
1206             object_get_typename(OBJECT(dev)), dev->id, s);
1207 
1208     return 0;
1209 }
1210 
1211 static const VMStateDescription vmstate_cadence_gem = {
1212     .name = "cadence_gem",
1213     .version_id = 2,
1214     .minimum_version_id = 2,
1215     .fields = (VMStateField[]) {
1216         VMSTATE_UINT32_ARRAY(regs, CadenceGEMState, CADENCE_GEM_MAXREG),
1217         VMSTATE_UINT16_ARRAY(phy_regs, CadenceGEMState, 32),
1218         VMSTATE_UINT8(phy_loop, CadenceGEMState),
1219         VMSTATE_UINT32(rx_desc_addr, CadenceGEMState),
1220         VMSTATE_UINT32(tx_desc_addr, CadenceGEMState),
1221         VMSTATE_BOOL_ARRAY(sar_active, CadenceGEMState, 4),
1222         VMSTATE_END_OF_LIST(),
1223     }
1224 };
1225 
1226 static Property gem_properties[] = {
1227     DEFINE_NIC_PROPERTIES(CadenceGEMState, conf),
1228     DEFINE_PROP_END_OF_LIST(),
1229 };
1230 
1231 static void gem_class_init(ObjectClass *klass, void *data)
1232 {
1233     DeviceClass *dc = DEVICE_CLASS(klass);
1234     SysBusDeviceClass *sdc = SYS_BUS_DEVICE_CLASS(klass);
1235 
1236     sdc->init = gem_init;
1237     dc->props = gem_properties;
1238     dc->vmsd = &vmstate_cadence_gem;
1239     dc->reset = gem_reset;
1240 }
1241 
1242 static const TypeInfo gem_info = {
1243     .name  = TYPE_CADENCE_GEM,
1244     .parent = TYPE_SYS_BUS_DEVICE,
1245     .instance_size  = sizeof(CadenceGEMState),
1246     .class_init = gem_class_init,
1247 };
1248 
1249 static void gem_register_types(void)
1250 {
1251     type_register_static(&gem_info);
1252 }
1253 
1254 type_init(gem_register_types)
1255