xref: /openbmc/qemu/hw/ppc/pnv_i2c.c (revision 7200fb21)
1 /*
2  * QEMU PowerPC PowerNV Processor I2C model
3  *
4  * Copyright (c) 2019-2023, IBM Corporation.
5  *
6  * SPDX-License-Identifier: GPL-2.0-or-later
7  */
8 
9 #include "qemu/osdep.h"
10 #include "qemu/module.h"
11 #include "qemu/log.h"
12 #include "sysemu/reset.h"
13 
14 #include "hw/irq.h"
15 #include "hw/qdev-properties.h"
16 
17 #include "hw/ppc/pnv.h"
18 #include "hw/ppc/pnv_chip.h"
19 #include "hw/ppc/pnv_i2c.h"
20 #include "hw/ppc/pnv_xscom.h"
21 #include "hw/ppc/fdt.h"
22 
23 #include <libfdt.h>
24 
25 /* I2C FIFO register */
26 #define I2C_FIFO_REG                    0x4
27 #define I2C_FIFO                        PPC_BITMASK(0, 7)
28 
29 /* I2C command register */
30 #define I2C_CMD_REG                     0x5
31 #define I2C_CMD_WITH_START              PPC_BIT(0)
32 #define I2C_CMD_WITH_ADDR               PPC_BIT(1)
33 #define I2C_CMD_READ_CONT               PPC_BIT(2)
34 #define I2C_CMD_WITH_STOP               PPC_BIT(3)
35 #define I2C_CMD_INTR_STEERING           PPC_BITMASK(6, 7) /* P9 */
36 #define   I2C_CMD_INTR_STEER_HOST       1
37 #define   I2C_CMD_INTR_STEER_OCC        2
38 #define I2C_CMD_DEV_ADDR                PPC_BITMASK(8, 14)
39 #define I2C_CMD_READ_NOT_WRITE          PPC_BIT(15)
40 #define I2C_CMD_LEN_BYTES               PPC_BITMASK(16, 31)
41 #define I2C_MAX_TFR_LEN                 0xfff0ull
42 
43 /* I2C mode register */
44 #define I2C_MODE_REG                    0x6
45 #define I2C_MODE_BIT_RATE_DIV           PPC_BITMASK(0, 15)
46 #define I2C_MODE_PORT_NUM               PPC_BITMASK(16, 21)
47 #define I2C_MODE_ENHANCED               PPC_BIT(28)
48 #define I2C_MODE_DIAGNOSTIC             PPC_BIT(29)
49 #define I2C_MODE_PACING_ALLOW           PPC_BIT(30)
50 #define I2C_MODE_WRAP                   PPC_BIT(31)
51 
52 /* I2C watermark register */
53 #define I2C_WATERMARK_REG               0x7
54 #define I2C_WATERMARK_HIGH              PPC_BITMASK(16, 19)
55 #define I2C_WATERMARK_LOW               PPC_BITMASK(24, 27)
56 
57 /*
58  * I2C interrupt mask and condition registers
59  *
60  * NB: The function of 0x9 and 0xa changes depending on whether you're reading
61  *     or writing to them. When read they return the interrupt condition bits
62  *     and on writes they update the interrupt mask register.
63  *
64  *  The bit definitions are the same for all the interrupt registers.
65  */
66 #define I2C_INTR_MASK_REG               0x8
67 
68 #define I2C_INTR_RAW_COND_REG           0x9 /* read */
69 #define I2C_INTR_MASK_OR_REG            0x9 /* write*/
70 
71 #define I2C_INTR_COND_REG               0xa /* read */
72 #define I2C_INTR_MASK_AND_REG           0xa /* write */
73 
74 #define I2C_INTR_ALL                    PPC_BITMASK(16, 31)
75 #define I2C_INTR_INVALID_CMD            PPC_BIT(16)
76 #define I2C_INTR_LBUS_PARITY_ERR        PPC_BIT(17)
77 #define I2C_INTR_BKEND_OVERRUN_ERR      PPC_BIT(18)
78 #define I2C_INTR_BKEND_ACCESS_ERR       PPC_BIT(19)
79 #define I2C_INTR_ARBT_LOST_ERR          PPC_BIT(20)
80 #define I2C_INTR_NACK_RCVD_ERR          PPC_BIT(21)
81 #define I2C_INTR_DATA_REQ               PPC_BIT(22)
82 #define I2C_INTR_CMD_COMP               PPC_BIT(23)
83 #define I2C_INTR_STOP_ERR               PPC_BIT(24)
84 #define I2C_INTR_I2C_BUSY               PPC_BIT(25)
85 #define I2C_INTR_NOT_I2C_BUSY           PPC_BIT(26)
86 #define I2C_INTR_SCL_EQ_1               PPC_BIT(28)
87 #define I2C_INTR_SCL_EQ_0               PPC_BIT(29)
88 #define I2C_INTR_SDA_EQ_1               PPC_BIT(30)
89 #define I2C_INTR_SDA_EQ_0               PPC_BIT(31)
90 
91 /* I2C status register */
92 #define I2C_RESET_I2C_REG               0xb /* write */
93 #define I2C_RESET_ERRORS                0xc
94 #define I2C_STAT_REG                    0xb /* read */
95 #define I2C_STAT_INVALID_CMD            PPC_BIT(0)
96 #define I2C_STAT_LBUS_PARITY_ERR        PPC_BIT(1)
97 #define I2C_STAT_BKEND_OVERRUN_ERR      PPC_BIT(2)
98 #define I2C_STAT_BKEND_ACCESS_ERR       PPC_BIT(3)
99 #define I2C_STAT_ARBT_LOST_ERR          PPC_BIT(4)
100 #define I2C_STAT_NACK_RCVD_ERR          PPC_BIT(5)
101 #define I2C_STAT_DATA_REQ               PPC_BIT(6)
102 #define I2C_STAT_CMD_COMP               PPC_BIT(7)
103 #define I2C_STAT_STOP_ERR               PPC_BIT(8)
104 #define I2C_STAT_UPPER_THRS             PPC_BITMASK(9, 15)
105 #define I2C_STAT_ANY_I2C_INTR           PPC_BIT(16)
106 #define I2C_STAT_PORT_HISTORY_BUSY      PPC_BIT(19)
107 #define I2C_STAT_SCL_INPUT_LEVEL        PPC_BIT(20)
108 #define I2C_STAT_SDA_INPUT_LEVEL        PPC_BIT(21)
109 #define I2C_STAT_PORT_BUSY              PPC_BIT(22)
110 #define I2C_STAT_INTERFACE_BUSY         PPC_BIT(23)
111 #define I2C_STAT_FIFO_ENTRY_COUNT       PPC_BITMASK(24, 31)
112 
113 #define I2C_STAT_ANY_ERR (I2C_STAT_INVALID_CMD | I2C_STAT_LBUS_PARITY_ERR | \
114                           I2C_STAT_BKEND_OVERRUN_ERR | \
115                           I2C_STAT_BKEND_ACCESS_ERR | I2C_STAT_ARBT_LOST_ERR | \
116                           I2C_STAT_NACK_RCVD_ERR | I2C_STAT_STOP_ERR)
117 
118 
119 #define I2C_INTR_ACTIVE \
120         ((I2C_STAT_ANY_ERR >> 16) | I2C_INTR_CMD_COMP | I2C_INTR_DATA_REQ)
121 
122 /* Pseudo-status used for timeouts */
123 #define I2C_STAT_PSEUDO_TIMEOUT         PPC_BIT(63)
124 
125 /* I2C extended status register */
126 #define I2C_EXTD_STAT_REG               0xc
127 #define I2C_EXTD_STAT_FIFO_SIZE         PPC_BITMASK(0, 7)
128 #define I2C_EXTD_STAT_MSM_CURSTATE      PPC_BITMASK(11, 15)
129 #define I2C_EXTD_STAT_SCL_IN_SYNC       PPC_BIT(16)
130 #define I2C_EXTD_STAT_SDA_IN_SYNC       PPC_BIT(17)
131 #define I2C_EXTD_STAT_S_SCL             PPC_BIT(18)
132 #define I2C_EXTD_STAT_S_SDA             PPC_BIT(19)
133 #define I2C_EXTD_STAT_M_SCL             PPC_BIT(20)
134 #define I2C_EXTD_STAT_M_SDA             PPC_BIT(21)
135 #define I2C_EXTD_STAT_HIGH_WATER        PPC_BIT(22)
136 #define I2C_EXTD_STAT_LOW_WATER         PPC_BIT(23)
137 #define I2C_EXTD_STAT_I2C_BUSY          PPC_BIT(24)
138 #define I2C_EXTD_STAT_SELF_BUSY         PPC_BIT(25)
139 #define I2C_EXTD_STAT_I2C_VERSION       PPC_BITMASK(27, 31)
140 
141 /* I2C residual front end/back end length */
142 #define I2C_RESIDUAL_LEN_REG            0xd
143 #define I2C_RESIDUAL_FRONT_END          PPC_BITMASK(0, 15)
144 #define I2C_RESIDUAL_BACK_END           PPC_BITMASK(16, 31)
145 
146 /* Port busy register */
147 #define I2C_PORT_BUSY_REG               0xe
148 #define I2C_SET_S_SCL_REG               0xd
149 #define I2C_RESET_S_SCL_REG             0xf
150 #define I2C_SET_S_SDA_REG               0x10
151 #define I2C_RESET_S_SDA_REG             0x11
152 
153 #define PNV_I2C_FIFO_SIZE 8
154 
155 static I2CBus *pnv_i2c_get_bus(PnvI2C *i2c)
156 {
157     uint8_t port = GETFIELD(I2C_MODE_PORT_NUM, i2c->regs[I2C_MODE_REG]);
158 
159     if (port >= i2c->num_busses) {
160         qemu_log_mask(LOG_GUEST_ERROR, "I2C: invalid bus number %d/%d\n", port,
161                       i2c->num_busses);
162         return NULL;
163     }
164     return i2c->busses[port];
165 }
166 
167 static void pnv_i2c_update_irq(PnvI2C *i2c)
168 {
169     I2CBus *bus = pnv_i2c_get_bus(i2c);
170     bool recv = !!(i2c->regs[I2C_CMD_REG] & I2C_CMD_READ_NOT_WRITE);
171     uint16_t front_end = GETFIELD(I2C_RESIDUAL_FRONT_END,
172                                   i2c->regs[I2C_RESIDUAL_LEN_REG]);
173     uint16_t back_end = GETFIELD(I2C_RESIDUAL_BACK_END,
174                                  i2c->regs[I2C_RESIDUAL_LEN_REG]);
175     uint8_t fifo_count = GETFIELD(I2C_STAT_FIFO_ENTRY_COUNT,
176                                    i2c->regs[I2C_STAT_REG]);
177     uint8_t fifo_free = PNV_I2C_FIFO_SIZE - fifo_count;
178 
179     if (!bus) {
180         qemu_log_mask(LOG_GUEST_ERROR, "I2C: invalid port\n");
181         return;
182     }
183 
184     if (i2c_bus_busy(bus)) {
185         i2c->regs[I2C_STAT_REG] &= ~I2C_STAT_DATA_REQ;
186 
187         if (recv) {
188             if (fifo_count >=
189                 GETFIELD(I2C_WATERMARK_HIGH, i2c->regs[I2C_WATERMARK_REG])) {
190                 i2c->regs[I2C_EXTD_STAT_REG] |= I2C_EXTD_STAT_HIGH_WATER;
191             } else {
192                 i2c->regs[I2C_EXTD_STAT_REG] &= ~I2C_EXTD_STAT_HIGH_WATER;
193             }
194 
195             if (((i2c->regs[I2C_EXTD_STAT_REG] & I2C_EXTD_STAT_HIGH_WATER) &&
196                  fifo_count != 0) || front_end == 0) {
197                 i2c->regs[I2C_STAT_REG] |= I2C_STAT_DATA_REQ;
198             }
199         } else {
200             if (fifo_count <=
201                 GETFIELD(I2C_WATERMARK_LOW, i2c->regs[I2C_WATERMARK_REG])) {
202                 i2c->regs[I2C_EXTD_STAT_REG] |= I2C_EXTD_STAT_LOW_WATER;
203             } else {
204                 i2c->regs[I2C_EXTD_STAT_REG] &= ~I2C_EXTD_STAT_LOW_WATER;
205             }
206 
207             if (back_end > 0 &&
208                 (fifo_free >= back_end ||
209                  (i2c->regs[I2C_EXTD_STAT_REG] & I2C_EXTD_STAT_LOW_WATER))) {
210                 i2c->regs[I2C_STAT_REG] |= I2C_STAT_DATA_REQ;
211             }
212         }
213 
214         if (back_end == 0 && front_end == 0) {
215             i2c->regs[I2C_STAT_REG] &= ~I2C_STAT_DATA_REQ;
216             i2c->regs[I2C_STAT_REG] |= I2C_STAT_CMD_COMP;
217 
218             if (i2c->regs[I2C_CMD_REG] & I2C_CMD_WITH_STOP) {
219                 i2c_end_transfer(bus);
220                 i2c->regs[I2C_EXTD_STAT_REG] &=
221                     ~(I2C_EXTD_STAT_I2C_BUSY | I2C_EXTD_STAT_SELF_BUSY);
222             }
223         } else {
224             i2c->regs[I2C_STAT_REG] &= ~I2C_STAT_CMD_COMP;
225         }
226     }
227 
228     /*
229      * Status and interrupt registers have nearly the same layout.
230      */
231     i2c->regs[I2C_INTR_RAW_COND_REG] = i2c->regs[I2C_STAT_REG] >> 16;
232     i2c->regs[I2C_INTR_COND_REG] =
233         i2c->regs[I2C_INTR_RAW_COND_REG] & i2c->regs[I2C_INTR_MASK_REG];
234 
235     qemu_set_irq(i2c->psi_irq, i2c->regs[I2C_INTR_COND_REG] != 0);
236 }
237 
238 static void pnv_i2c_fifo_update_count(PnvI2C *i2c)
239 {
240     uint64_t stat = i2c->regs[I2C_STAT_REG];
241 
242     i2c->regs[I2C_STAT_REG] = SETFIELD(I2C_STAT_FIFO_ENTRY_COUNT, stat,
243                                        fifo8_num_used(&i2c->fifo));
244 }
245 
246 static void pnv_i2c_frontend_update(PnvI2C *i2c)
247 {
248     uint64_t residual_end = i2c->regs[I2C_RESIDUAL_LEN_REG];
249     uint16_t front_end = GETFIELD(I2C_RESIDUAL_FRONT_END, residual_end);
250 
251     i2c->regs[I2C_RESIDUAL_LEN_REG] =
252         SETFIELD(I2C_RESIDUAL_FRONT_END, residual_end, front_end - 1);
253 }
254 
255 static void pnv_i2c_fifo_flush(PnvI2C *i2c)
256 {
257     I2CBus *bus = pnv_i2c_get_bus(i2c);
258     uint8_t data;
259     int ret;
260 
261     if (!bus) {
262         qemu_log_mask(LOG_GUEST_ERROR, "I2C: invalid port\n");
263         return;
264     }
265     if (!i2c_bus_busy(bus)) {
266         return;
267     }
268 
269     if (i2c->regs[I2C_CMD_REG] & I2C_CMD_READ_NOT_WRITE) {
270         if (fifo8_is_full(&i2c->fifo)) {
271             return;
272         }
273 
274         data = i2c_recv(bus);
275         fifo8_push(&i2c->fifo, data);
276     } else {
277         if (fifo8_is_empty(&i2c->fifo)) {
278             return;
279         }
280 
281         data = fifo8_pop(&i2c->fifo);
282         ret = i2c_send(bus, data);
283         if (ret) {
284             i2c->regs[I2C_STAT_REG] |= I2C_STAT_NACK_RCVD_ERR;
285             i2c_end_transfer(bus);
286         }
287     }
288 
289     pnv_i2c_fifo_update_count(i2c);
290     pnv_i2c_frontend_update(i2c);
291 }
292 
293 static void pnv_i2c_handle_cmd(PnvI2C *i2c, uint64_t val)
294 {
295     I2CBus *bus = pnv_i2c_get_bus(i2c);
296     uint8_t addr = GETFIELD(I2C_CMD_DEV_ADDR, val);
297     int recv = !!(val & I2C_CMD_READ_NOT_WRITE);
298     uint32_t len_bytes = GETFIELD(I2C_CMD_LEN_BYTES, val);
299 
300     if (!(val & I2C_CMD_WITH_START) && !(val & I2C_CMD_WITH_ADDR) &&
301         !(val & I2C_CMD_WITH_STOP) && !len_bytes) {
302         i2c->regs[I2C_STAT_REG] |= I2C_STAT_INVALID_CMD;
303         qemu_log_mask(LOG_GUEST_ERROR, "I2C: invalid command 0x%"PRIx64"\n",
304                       val);
305         return;
306     }
307 
308     if (!(i2c->regs[I2C_STAT_REG] & I2C_STAT_CMD_COMP)) {
309         i2c->regs[I2C_STAT_REG] |= I2C_STAT_INVALID_CMD;
310         qemu_log_mask(LOG_GUEST_ERROR, "I2C: command in progress\n");
311         return;
312     }
313 
314     if (!bus) {
315         qemu_log_mask(LOG_GUEST_ERROR, "I2C: invalid port\n");
316         return;
317     }
318 
319     i2c->regs[I2C_RESIDUAL_LEN_REG] =
320         SETFIELD(I2C_RESIDUAL_FRONT_END, 0ull, len_bytes) |
321         SETFIELD(I2C_RESIDUAL_BACK_END, 0ull, len_bytes);
322 
323     if (val & I2C_CMD_WITH_START) {
324         if (i2c_start_transfer(bus, addr, recv)) {
325             i2c->regs[I2C_STAT_REG] |= I2C_STAT_NACK_RCVD_ERR;
326         } else {
327             i2c->regs[I2C_EXTD_STAT_REG] |=
328                 (I2C_EXTD_STAT_I2C_BUSY | I2C_EXTD_STAT_SELF_BUSY);
329             pnv_i2c_fifo_flush(i2c);
330         }
331     }
332 }
333 
334 static void pnv_i2c_backend_update(PnvI2C *i2c)
335 {
336     uint64_t residual_end = i2c->regs[I2C_RESIDUAL_LEN_REG];
337     uint16_t back_end = GETFIELD(I2C_RESIDUAL_BACK_END, residual_end);
338 
339     if (!back_end) {
340         i2c->regs[I2C_STAT_REG] |= I2C_STAT_BKEND_ACCESS_ERR;
341         return;
342     }
343 
344     i2c->regs[I2C_RESIDUAL_LEN_REG] =
345         SETFIELD(I2C_RESIDUAL_BACK_END, residual_end, back_end - 1);
346 }
347 
348 static void pnv_i2c_fifo_in(PnvI2C *i2c)
349 {
350     uint8_t data = GETFIELD(I2C_FIFO, i2c->regs[I2C_FIFO_REG]);
351     I2CBus *bus = pnv_i2c_get_bus(i2c);
352 
353     if (!bus) {
354         qemu_log_mask(LOG_GUEST_ERROR, "I2C: invalid port\n");
355         return;
356     }
357 
358     if (!i2c_bus_busy(bus)) {
359         i2c->regs[I2C_STAT_REG] |= I2C_STAT_INVALID_CMD;
360         qemu_log_mask(LOG_GUEST_ERROR, "I2C: no command in progress\n");
361         return;
362     }
363 
364     if (i2c->regs[I2C_CMD_REG] & I2C_CMD_READ_NOT_WRITE) {
365         i2c->regs[I2C_STAT_REG] |= I2C_STAT_INVALID_CMD;
366         qemu_log_mask(LOG_GUEST_ERROR, "I2C: read command in progress\n");
367         return;
368     }
369 
370     if (fifo8_is_full(&i2c->fifo)) {
371         if (!(i2c->regs[I2C_MODE_REG] & I2C_MODE_PACING_ALLOW)) {
372             i2c->regs[I2C_STAT_REG] |= I2C_STAT_BKEND_OVERRUN_ERR;
373         }
374         return;
375     }
376 
377     fifo8_push(&i2c->fifo, data);
378     pnv_i2c_fifo_update_count(i2c);
379     pnv_i2c_backend_update(i2c);
380     pnv_i2c_fifo_flush(i2c);
381 }
382 
383 static void pnv_i2c_fifo_out(PnvI2C *i2c)
384 {
385     uint8_t data;
386     I2CBus *bus = pnv_i2c_get_bus(i2c);
387 
388     if (!bus) {
389         qemu_log_mask(LOG_GUEST_ERROR, "I2C: invalid port\n");
390         return;
391     }
392 
393     if (!i2c_bus_busy(bus)) {
394         i2c->regs[I2C_STAT_REG] |= I2C_STAT_INVALID_CMD;
395         qemu_log_mask(LOG_GUEST_ERROR, "I2C: no command in progress\n");
396         return;
397     }
398 
399     if (!(i2c->regs[I2C_CMD_REG] & I2C_CMD_READ_NOT_WRITE)) {
400         i2c->regs[I2C_STAT_REG] |= I2C_STAT_INVALID_CMD;
401         qemu_log_mask(LOG_GUEST_ERROR, "I2C: write command in progress\n");
402         return;
403     }
404 
405     if (fifo8_is_empty(&i2c->fifo)) {
406         if (!(i2c->regs[I2C_MODE_REG] & I2C_MODE_PACING_ALLOW)) {
407             i2c->regs[I2C_STAT_REG] |= I2C_STAT_BKEND_OVERRUN_ERR;
408         }
409         return;
410     }
411 
412     data = fifo8_pop(&i2c->fifo);
413 
414     i2c->regs[I2C_FIFO_REG] = SETFIELD(I2C_FIFO, 0ull, data);
415     pnv_i2c_fifo_update_count(i2c);
416     pnv_i2c_backend_update(i2c);
417 }
418 
419 static uint64_t pnv_i2c_xscom_read(void *opaque, hwaddr addr,
420                                    unsigned size)
421 {
422     PnvI2C *i2c = PNV_I2C(opaque);
423     uint32_t offset = addr >> 3;
424     uint64_t val = -1;
425     int i;
426 
427     switch (offset) {
428     case I2C_STAT_REG:
429         val = i2c->regs[offset];
430         break;
431 
432     case I2C_FIFO_REG:
433         pnv_i2c_fifo_out(i2c);
434         val = i2c->regs[offset];
435         break;
436 
437     case I2C_PORT_BUSY_REG: /* compute busy bit for each port  */
438         val = 0;
439         for (i = 0; i < i2c->num_busses; i++) {
440             val |= i2c_bus_busy(i2c->busses[i]) << i;
441         }
442         break;
443 
444     case I2C_CMD_REG:
445     case I2C_MODE_REG:
446     case I2C_WATERMARK_REG:
447     case I2C_INTR_MASK_REG:
448     case I2C_INTR_RAW_COND_REG:
449     case I2C_INTR_COND_REG:
450     case I2C_EXTD_STAT_REG:
451     case I2C_RESIDUAL_LEN_REG:
452         val = i2c->regs[offset];
453         break;
454     default:
455         i2c->regs[I2C_STAT_REG] |= I2C_STAT_INVALID_CMD;
456         qemu_log_mask(LOG_GUEST_ERROR, "I2C: read at register: 0x%"
457                       HWADDR_PRIx "\n", addr >> 3);
458     }
459 
460     pnv_i2c_update_irq(i2c);
461 
462     return val;
463 }
464 
465 static void pnv_i2c_xscom_write(void *opaque, hwaddr addr,
466                                 uint64_t val, unsigned size)
467 {
468     PnvI2C *i2c = PNV_I2C(opaque);
469     uint32_t offset = addr >> 3;
470 
471     switch (offset) {
472     case I2C_MODE_REG:
473         {
474             i2c->regs[offset] = val;
475             I2CBus *bus = pnv_i2c_get_bus(i2c);
476             if (!bus) {
477                 qemu_log_mask(LOG_GUEST_ERROR, "I2C: invalid port\n");
478                 return;
479             }
480             if (i2c_bus_busy(bus)) {
481                 i2c->regs[I2C_STAT_REG] |= I2C_STAT_INVALID_CMD;
482                 qemu_log_mask(LOG_GUEST_ERROR, "I2C: command in progress\n");
483             }
484         }
485         break;
486 
487     case I2C_CMD_REG:
488         i2c->regs[offset] = val;
489         pnv_i2c_handle_cmd(i2c, val);
490         break;
491 
492     case I2C_FIFO_REG:
493         i2c->regs[offset] = val;
494         pnv_i2c_fifo_in(i2c);
495         break;
496 
497     case I2C_WATERMARK_REG:
498         i2c->regs[offset] = val;
499         break;
500 
501     case I2C_RESET_I2C_REG:
502         i2c->regs[I2C_MODE_REG] = 0;
503         i2c->regs[I2C_CMD_REG] = 0;
504         i2c->regs[I2C_WATERMARK_REG] = 0;
505         i2c->regs[I2C_INTR_MASK_REG] = 0;
506         i2c->regs[I2C_INTR_COND_REG] = 0;
507         i2c->regs[I2C_INTR_RAW_COND_REG] = 0;
508         i2c->regs[I2C_STAT_REG] = 0;
509         i2c->regs[I2C_RESIDUAL_LEN_REG] = 0;
510         i2c->regs[I2C_EXTD_STAT_REG] &=
511             (I2C_EXTD_STAT_FIFO_SIZE | I2C_EXTD_STAT_I2C_VERSION);
512         break;
513 
514     case I2C_RESET_ERRORS:
515         i2c->regs[I2C_STAT_REG] &= ~I2C_STAT_ANY_ERR;
516         i2c->regs[I2C_RESIDUAL_LEN_REG] = 0;
517         i2c->regs[I2C_EXTD_STAT_REG] &=
518             (I2C_EXTD_STAT_FIFO_SIZE | I2C_EXTD_STAT_I2C_VERSION);
519         fifo8_reset(&i2c->fifo);
520         break;
521 
522     case I2C_INTR_MASK_REG:
523         i2c->regs[offset] = val;
524         break;
525 
526     case I2C_INTR_MASK_OR_REG:
527         i2c->regs[I2C_INTR_MASK_REG] |= val;
528         break;
529 
530     case I2C_INTR_MASK_AND_REG:
531         i2c->regs[I2C_INTR_MASK_REG] &= val;
532         break;
533 
534     case I2C_PORT_BUSY_REG:
535     case I2C_SET_S_SCL_REG:
536     case I2C_RESET_S_SCL_REG:
537     case I2C_SET_S_SDA_REG:
538     case I2C_RESET_S_SDA_REG:
539         i2c->regs[offset] = val;
540         break;
541     default:
542         i2c->regs[I2C_STAT_REG] |= I2C_STAT_INVALID_CMD;
543         qemu_log_mask(LOG_GUEST_ERROR, "I2C: write at register: 0x%"
544                       HWADDR_PRIx " val=0x%"PRIx64"\n", addr >> 3, val);
545     }
546 
547     pnv_i2c_update_irq(i2c);
548 }
549 
550 static const MemoryRegionOps pnv_i2c_xscom_ops = {
551     .read = pnv_i2c_xscom_read,
552     .write = pnv_i2c_xscom_write,
553     .valid.min_access_size = 8,
554     .valid.max_access_size = 8,
555     .impl.min_access_size = 8,
556     .impl.max_access_size = 8,
557     .endianness = DEVICE_BIG_ENDIAN,
558 };
559 
560 static int pnv_i2c_bus_dt_xscom(PnvI2C *i2c, void *fdt,
561                                 int offset, int index)
562 {
563     int i2c_bus_offset;
564     const char i2c_compat[] =
565         "ibm,opal-i2c\0ibm,power8-i2c-port\0ibm,power9-i2c-port";
566     g_autofree char *i2c_port_name = NULL;
567     g_autofree char *name = g_strdup_printf("i2c-bus@%x", index);
568 
569     i2c_bus_offset = fdt_add_subnode(fdt, offset, name);
570     _FDT(i2c_bus_offset);
571 
572     _FDT((fdt_setprop_cell(fdt, i2c_bus_offset, "reg", index)));
573     _FDT((fdt_setprop_cell(fdt, i2c_bus_offset, "#address-cells", 1)));
574     _FDT((fdt_setprop_cell(fdt, i2c_bus_offset, "#size-cells", 0)));
575     _FDT(fdt_setprop(fdt, i2c_bus_offset, "compatible", i2c_compat,
576                      sizeof(i2c_compat)));
577     _FDT((fdt_setprop_cell(fdt, i2c_bus_offset, "bus-frequency", 400000)));
578 
579     i2c_port_name = g_strdup_printf("p8_%08x_e%dp%d", i2c->chip->chip_id,
580                                     i2c->engine, index);
581     _FDT(fdt_setprop_string(fdt, i2c_bus_offset, "ibm,port-name",
582                             i2c_port_name));
583     return 0;
584 }
585 
586 #define XSCOM_BUS_FREQUENCY 466500000
587 #define I2C_CLOCK_FREQUENCY (XSCOM_BUS_FREQUENCY / 4)
588 
589 static int pnv_i2c_dt_xscom(PnvXScomInterface *dev, void *fdt,
590                             int offset)
591 {
592     PnvI2C *i2c = PNV_I2C(dev);
593     int i2c_offset;
594     const char i2c_compat[] = "ibm,power8-i2cm\0ibm,power9-i2cm";
595     uint32_t i2c_pcba = PNV9_XSCOM_I2CM_BASE +
596         i2c->engine * PNV9_XSCOM_I2CM_SIZE;
597     uint32_t reg[2] = {
598         cpu_to_be32(i2c_pcba),
599         cpu_to_be32(PNV9_XSCOM_I2CM_SIZE)
600     };
601     int i;
602     g_autofree char *name = g_strdup_printf("i2cm@%x", i2c_pcba);
603 
604     i2c_offset = fdt_add_subnode(fdt, offset, name);
605     _FDT(i2c_offset);
606 
607     _FDT(fdt_setprop(fdt, i2c_offset, "reg", reg, sizeof(reg)));
608 
609     _FDT((fdt_setprop_cell(fdt, i2c_offset, "#address-cells", 1)));
610     _FDT((fdt_setprop_cell(fdt, i2c_offset, "#size-cells", 0)));
611     _FDT(fdt_setprop(fdt, i2c_offset, "compatible", i2c_compat,
612                      sizeof(i2c_compat)));
613     _FDT((fdt_setprop_cell(fdt, i2c_offset, "chip-engine#", i2c->engine)));
614     _FDT((fdt_setprop_cell(fdt, i2c_offset, "clock-frequency",
615                            I2C_CLOCK_FREQUENCY)));
616 
617     for (i = 0; i < i2c->num_busses; i++) {
618         pnv_i2c_bus_dt_xscom(i2c, fdt, i2c_offset, i);
619     }
620     return 0;
621 }
622 
623 static void pnv_i2c_reset(void *dev)
624 {
625     PnvI2C *i2c = PNV_I2C(dev);
626 
627     memset(i2c->regs, 0, sizeof(i2c->regs));
628 
629     i2c->regs[I2C_STAT_REG] = I2C_STAT_CMD_COMP;
630     i2c->regs[I2C_EXTD_STAT_REG] =
631         SETFIELD(I2C_EXTD_STAT_FIFO_SIZE, 0ull, PNV_I2C_FIFO_SIZE) |
632         SETFIELD(I2C_EXTD_STAT_I2C_VERSION, 0ull, 23); /* last version */
633 
634     fifo8_reset(&i2c->fifo);
635 }
636 
637 static void pnv_i2c_realize(DeviceState *dev, Error **errp)
638 {
639     PnvI2C *i2c = PNV_I2C(dev);
640     int i;
641 
642     assert(i2c->chip);
643 
644     pnv_xscom_region_init(&i2c->xscom_regs, OBJECT(i2c), &pnv_i2c_xscom_ops,
645                           i2c, "xscom-i2c", PNV9_XSCOM_I2CM_SIZE);
646 
647     i2c->busses = g_new(I2CBus *, i2c->num_busses);
648     for (i = 0; i < i2c->num_busses; i++) {
649         char name[32];
650 
651         snprintf(name, sizeof(name), TYPE_PNV_I2C ".%d", i);
652         i2c->busses[i] = i2c_init_bus(dev, name);
653     }
654 
655     fifo8_create(&i2c->fifo, PNV_I2C_FIFO_SIZE);
656 
657     qemu_register_reset(pnv_i2c_reset, dev);
658 
659     qdev_init_gpio_out(DEVICE(dev), &i2c->psi_irq, 1);
660 }
661 
662 static Property pnv_i2c_properties[] = {
663     DEFINE_PROP_LINK("chip", PnvI2C, chip, TYPE_PNV_CHIP, PnvChip *),
664     DEFINE_PROP_UINT32("engine", PnvI2C, engine, 1),
665     DEFINE_PROP_UINT32("num-busses", PnvI2C, num_busses, 1),
666     DEFINE_PROP_END_OF_LIST(),
667 };
668 
669 static void pnv_i2c_class_init(ObjectClass *klass, void *data)
670 {
671     DeviceClass *dc = DEVICE_CLASS(klass);
672     PnvXScomInterfaceClass *xscomc = PNV_XSCOM_INTERFACE_CLASS(klass);
673 
674     xscomc->dt_xscom = pnv_i2c_dt_xscom;
675 
676     dc->desc = "PowerNV I2C";
677     dc->realize = pnv_i2c_realize;
678     device_class_set_props(dc, pnv_i2c_properties);
679 }
680 
681 static const TypeInfo pnv_i2c_info = {
682     .name          = TYPE_PNV_I2C,
683     .parent        = TYPE_DEVICE,
684     .instance_size = sizeof(PnvI2C),
685     .class_init    = pnv_i2c_class_init,
686     .interfaces    = (InterfaceInfo[]) {
687         { TYPE_PNV_XSCOM_INTERFACE },
688         { }
689     }
690 };
691 
692 static void pnv_i2c_register_types(void)
693 {
694     type_register_static(&pnv_i2c_info);
695 }
696 
697 type_init(pnv_i2c_register_types);
698