xref: /openbmc/qemu/hw/ssi/pnv_spi.c (revision fac933ca)
1 /*
2  * QEMU PowerPC SPI model
3  *
4  * Copyright (c) 2024, IBM Corporation.
5  *
6  * SPDX-License-Identifier: GPL-2.0-or-later
7  */
8 
9 #include "qemu/osdep.h"
10 #include "qemu/log.h"
11 #include "hw/qdev-properties.h"
12 #include "hw/ppc/pnv_xscom.h"
13 #include "hw/ssi/pnv_spi.h"
14 #include "hw/ssi/pnv_spi_regs.h"
15 #include "hw/ssi/ssi.h"
16 #include <libfdt.h>
17 #include "hw/irq.h"
18 #include "trace.h"
19 
20 #define PNV_SPI_OPCODE_LO_NIBBLE(x) (x & 0x0F)
21 #define PNV_SPI_MASKED_OPCODE(x) (x & 0xF0)
22 
23 /*
24  * Macro from include/hw/ppc/fdt.h
25  * fdt.h cannot be included here as it contain ppc target specific dependency.
26  */
27 #define _FDT(exp)                                                  \
28     do {                                                           \
29         int _ret = (exp);                                          \
30         if (_ret < 0) {                                            \
31             qemu_log_mask(LOG_GUEST_ERROR,                         \
32                     "error creating device tree: %s: %s",          \
33                     #exp, fdt_strerror(_ret));                     \
34             exit(1);                                               \
35         }                                                          \
36     } while (0)
37 
38 /* PnvXferBuffer */
39 typedef struct PnvXferBuffer {
40 
41     uint32_t    len;
42     uint8_t    *data;
43 
44 } PnvXferBuffer;
45 
46 /* pnv_spi_xfer_buffer_methods */
47 static PnvXferBuffer *pnv_spi_xfer_buffer_new(void)
48 {
49     PnvXferBuffer *payload = g_malloc0(sizeof(*payload));
50 
51     return payload;
52 }
53 
54 static void pnv_spi_xfer_buffer_free(PnvXferBuffer *payload)
55 {
56     g_free(payload->data);
57     g_free(payload);
58 }
59 
60 static uint8_t *pnv_spi_xfer_buffer_write_ptr(PnvXferBuffer *payload,
61                 uint32_t offset, uint32_t length)
62 {
63     if (payload->len < (offset + length)) {
64         payload->len = offset + length;
65         payload->data = g_realloc(payload->data, payload->len);
66     }
67     return &payload->data[offset];
68 }
69 
70 static bool does_rdr_match(PnvSpi *s)
71 {
72     /*
73      * According to spec, the mask bits that are 0 are compared and the
74      * bits that are 1 are ignored.
75      */
76     uint16_t rdr_match_mask = GETFIELD(SPI_MM_RDR_MATCH_MASK,
77                                         s->regs[SPI_MM_REG]);
78     uint16_t rdr_match_val = GETFIELD(SPI_MM_RDR_MATCH_VAL,
79                                         s->regs[SPI_MM_REG]);
80 
81     if ((~rdr_match_mask & rdr_match_val) == ((~rdr_match_mask) &
82             GETFIELD(PPC_BITMASK(48, 63), s->regs[SPI_RCV_DATA_REG]))) {
83         return true;
84     }
85     return false;
86 }
87 
88 static uint8_t get_from_offset(PnvSpi *s, uint8_t offset)
89 {
90     uint8_t byte;
91 
92     /*
93      * Offset is an index between 0 and PNV_SPI_REG_SIZE - 1
94      * Check the offset before using it.
95      */
96     if (offset < PNV_SPI_REG_SIZE) {
97         byte = (s->regs[SPI_XMIT_DATA_REG] >> (56 - offset * 8)) & 0xFF;
98     } else {
99         /*
100          * Log an error and return a 0xFF since we have to assign something
101          * to byte before returning.
102          */
103         qemu_log_mask(LOG_GUEST_ERROR, "Invalid offset = %d used to get byte "
104                       "from TDR\n", offset);
105         byte = 0xff;
106     }
107     return byte;
108 }
109 
110 static uint8_t read_from_frame(PnvSpi *s, uint8_t *read_buf, uint8_t nr_bytes,
111                 uint8_t ecc_count, uint8_t shift_in_count)
112 {
113     uint8_t byte;
114     int count = 0;
115 
116     while (count < nr_bytes) {
117         shift_in_count++;
118         if ((ecc_count != 0) &&
119             (shift_in_count == (PNV_SPI_REG_SIZE + ecc_count))) {
120             shift_in_count = 0;
121         } else {
122             byte = read_buf[count];
123             trace_pnv_spi_shift_rx(byte, count);
124             s->regs[SPI_RCV_DATA_REG] = (s->regs[SPI_RCV_DATA_REG] << 8) | byte;
125         }
126         count++;
127     } /* end of while */
128     return shift_in_count;
129 }
130 
131 static void spi_response(PnvSpi *s, int bits, PnvXferBuffer *rsp_payload)
132 {
133     uint8_t ecc_count;
134     uint8_t shift_in_count;
135 
136     /*
137      * Processing here must handle:
138      * - Which bytes in the payload we should move to the RDR
139      * - Explicit mode counter configuration settings
140      * - RDR full and RDR overrun status
141      */
142 
143     /*
144      * First check that the response payload is the exact same
145      * number of bytes as the request payload was
146      */
147     if (rsp_payload->len != (s->N1_bytes + s->N2_bytes)) {
148         qemu_log_mask(LOG_GUEST_ERROR, "Invalid response payload size in "
149                        "bytes, expected %d, got %d\n",
150                        (s->N1_bytes + s->N2_bytes), rsp_payload->len);
151     } else {
152         uint8_t ecc_control;
153         trace_pnv_spi_rx_received(rsp_payload->len);
154         trace_pnv_spi_log_Ncounts(s->N1_bits, s->N1_bytes, s->N1_tx,
155                         s->N1_rx, s->N2_bits, s->N2_bytes, s->N2_tx, s->N2_rx);
156         /*
157          * Adding an ECC count let's us know when we have found a payload byte
158          * that was shifted in but cannot be loaded into RDR.  Bits 29-30 of
159          * clock_config_reset_control register equal to either 0b00 or 0b10
160          * indicate that we are taking in data with ECC and either applying
161          * the ECC or discarding it.
162          */
163         ecc_count = 0;
164         ecc_control = GETFIELD(SPI_CLK_CFG_ECC_CTRL, s->regs[SPI_CLK_CFG_REG]);
165         if (ecc_control == 0 || ecc_control == 2) {
166             ecc_count = 1;
167         }
168         /*
169          * Use the N1_rx and N2_rx counts to control shifting data from the
170          * payload into the RDR.  Keep an overall count of the number of bytes
171          * shifted into RDR so we can discard every 9th byte when ECC is
172          * enabled.
173          */
174         shift_in_count = 0;
175         /* Handle the N1 portion of the frame first */
176         if (s->N1_rx != 0) {
177             trace_pnv_spi_rx_read_N1frame();
178             shift_in_count = read_from_frame(s, &rsp_payload->data[0],
179                             s->N1_bytes, ecc_count, shift_in_count);
180         }
181         /* Handle the N2 portion of the frame */
182         if (s->N2_rx != 0) {
183             trace_pnv_spi_rx_read_N2frame();
184             shift_in_count = read_from_frame(s,
185                             &rsp_payload->data[s->N1_bytes], s->N2_bytes,
186                             ecc_count, shift_in_count);
187         }
188         if ((s->N1_rx + s->N2_rx) > 0) {
189             /*
190              * Data was received so handle RDR status.
191              * It is easier to handle RDR_full and RDR_overrun status here
192              * since the RDR register's shift_byte_in method is called
193              * multiple times in a row. Controlling RDR status is done here
194              * instead of in the RDR scoped methods for that reason.
195              */
196             if (GETFIELD(SPI_STS_RDR_FULL, s->status) == 1) {
197                 /*
198                  * Data was shifted into the RDR before having been read
199                  * causing previous data to have been overrun.
200                  */
201                 s->status = SETFIELD(SPI_STS_RDR_OVERRUN, s->status, 1);
202             } else {
203                 /*
204                  * Set status to indicate that the received data register is
205                  * full. This flag is only cleared once the RDR is unloaded.
206                  */
207                 s->status = SETFIELD(SPI_STS_RDR_FULL, s->status, 1);
208             }
209         }
210     } /* end of else */
211 } /* end of spi_response() */
212 
213 static void transfer(PnvSpi *s, PnvXferBuffer *payload)
214 {
215     uint32_t tx;
216     uint32_t rx;
217     PnvXferBuffer *rsp_payload = NULL;
218 
219     rsp_payload = pnv_spi_xfer_buffer_new();
220     if (!rsp_payload) {
221         return;
222     }
223     for (int offset = 0; offset < payload->len; offset += s->transfer_len) {
224         tx = 0;
225         for (int i = 0; i < s->transfer_len; i++) {
226             if ((offset + i) >= payload->len) {
227                 tx <<= 8;
228             } else {
229                 tx = (tx << 8) | payload->data[offset + i];
230             }
231         }
232         rx = ssi_transfer(s->ssi_bus, tx);
233         for (int i = 0; i < s->transfer_len; i++) {
234             if ((offset + i) >= payload->len) {
235                 break;
236             }
237             *(pnv_spi_xfer_buffer_write_ptr(rsp_payload, rsp_payload->len, 1)) =
238                     (rx >> (8 * (s->transfer_len - 1) - i * 8)) & 0xFF;
239         }
240     }
241     spi_response(s, s->N1_bits, rsp_payload);
242     pnv_spi_xfer_buffer_free(rsp_payload);
243 }
244 
245 static inline uint8_t get_seq_index(PnvSpi *s)
246 {
247     return GETFIELD(SPI_STS_SEQ_INDEX, s->status);
248 }
249 
250 static inline void next_sequencer_fsm(PnvSpi *s)
251 {
252     uint8_t seq_index = get_seq_index(s);
253     s->status = SETFIELD(SPI_STS_SEQ_INDEX, s->status, (seq_index + 1));
254     s->status = SETFIELD(SPI_STS_SEQ_FSM, s->status, SEQ_STATE_INDEX_INCREMENT);
255 }
256 
257 /*
258  * Calculate the N1 counters based on passed in opcode and
259  * internal register values.
260  * The method assumes that the opcode is a Shift_N1 opcode
261  * and doesn't test it.
262  * The counters returned are:
263  * N1 bits: Number of bits in the payload data that are significant
264  * to the responder.
265  * N1_bytes: Total count of payload bytes for the N1 (portion of the) frame.
266  * N1_tx: Total number of bytes taken from TDR for N1
267  * N1_rx: Total number of bytes taken from the payload for N1
268  */
269 static void calculate_N1(PnvSpi *s, uint8_t opcode)
270 {
271     /*
272      * Shift_N1 opcode form: 0x3M
273      * Implicit mode:
274      * If M != 0 the shift count is M bytes and M is the number of tx bytes.
275      * Forced Implicit mode:
276      * M is the shift count but tx and rx is determined by the count control
277      * register fields.  Note that we only check for forced Implicit mode when
278      * M != 0 since the mode doesn't make sense when M = 0.
279      * Explicit mode:
280      * If M == 0 then shift count is number of bits defined in the
281      * Counter Configuration Register's shift_count_N1 field.
282      */
283     if (PNV_SPI_OPCODE_LO_NIBBLE(opcode) == 0) {
284         /* Explicit mode */
285         s->N1_bits = GETFIELD(SPI_CTR_CFG_N1, s->regs[SPI_CTR_CFG_REG]);
286         s->N1_bytes = (s->N1_bits + 7) / 8;
287         s->N1_tx = 0;
288         s->N1_rx = 0;
289         /* If tx count control for N1 is set, load the tx value */
290         if (GETFIELD(SPI_CTR_CFG_N1_CTRL_B2, s->regs[SPI_CTR_CFG_REG]) == 1) {
291             s->N1_tx = s->N1_bytes;
292         }
293         /* If rx count control for N1 is set, load the rx value */
294         if (GETFIELD(SPI_CTR_CFG_N1_CTRL_B3, s->regs[SPI_CTR_CFG_REG]) == 1) {
295             s->N1_rx = s->N1_bytes;
296         }
297     } else {
298         /* Implicit mode/Forced Implicit mode, use M field from opcode */
299         s->N1_bytes = PNV_SPI_OPCODE_LO_NIBBLE(opcode);
300         s->N1_bits = s->N1_bytes * 8;
301         /*
302          * Assume that we are going to transmit the count
303          * (pure Implicit only)
304          */
305         s->N1_tx = s->N1_bytes;
306         s->N1_rx = 0;
307         /* Let Forced Implicit mode have an effect on the counts */
308         if (GETFIELD(SPI_CTR_CFG_N1_CTRL_B1, s->regs[SPI_CTR_CFG_REG]) == 1) {
309             /*
310              * If Forced Implicit mode and count control doesn't
311              * indicate transmit then reset the tx count to 0
312              */
313             if (GETFIELD(SPI_CTR_CFG_N1_CTRL_B2,
314                                     s->regs[SPI_CTR_CFG_REG]) == 0) {
315                 s->N1_tx = 0;
316             }
317             /* If rx count control for N1 is set, load the rx value */
318             if (GETFIELD(SPI_CTR_CFG_N1_CTRL_B3,
319                                     s->regs[SPI_CTR_CFG_REG]) == 1) {
320                 s->N1_rx = s->N1_bytes;
321             }
322         }
323     }
324     /*
325      * Enforce an upper limit on the size of N1 that is equal to the known size
326      * of the shift register, 64 bits or 72 bits if ECC is enabled.
327      * If the size exceeds 72 bits it is a user error so log an error,
328      * cap the size at a max of 64 bits or 72 bits and set the sequencer FSM
329      * error bit.
330      */
331     uint8_t ecc_control = GETFIELD(SPI_CLK_CFG_ECC_CTRL,
332                                    s->regs[SPI_CLK_CFG_REG]);
333     if (ecc_control == 0 || ecc_control == 2) {
334         if (s->N1_bytes > (PNV_SPI_REG_SIZE + 1)) {
335             qemu_log_mask(LOG_GUEST_ERROR, "Unsupported N1 shift size when "
336                           "ECC enabled, bytes = 0x%x, bits = 0x%x\n",
337                           s->N1_bytes, s->N1_bits);
338             s->N1_bytes = PNV_SPI_REG_SIZE + 1;
339             s->N1_bits = s->N1_bytes * 8;
340         }
341     } else if (s->N1_bytes > PNV_SPI_REG_SIZE) {
342         qemu_log_mask(LOG_GUEST_ERROR, "Unsupported N1 shift size, "
343                       "bytes = 0x%x, bits = 0x%x\n",
344                       s->N1_bytes, s->N1_bits);
345         s->N1_bytes = PNV_SPI_REG_SIZE;
346         s->N1_bits = s->N1_bytes * 8;
347     }
348 } /* end of calculate_N1 */
349 
350 /*
351  * Shift_N1 operation handler method
352  */
353 static bool operation_shiftn1(PnvSpi *s, uint8_t opcode,
354                        PnvXferBuffer **payload, bool send_n1_alone)
355 {
356     uint8_t n1_count;
357     bool stop = false;
358 
359     /*
360      * If there isn't a current payload left over from a stopped sequence
361      * create a new one.
362      */
363     if (*payload == NULL) {
364         *payload = pnv_spi_xfer_buffer_new();
365     }
366     /*
367      * Use a combination of N1 counters to build the N1 portion of the
368      * transmit payload.
369      * We only care about transmit at this time since the request payload
370      * only represents data going out on the controller output line.
371      * Leave mode specific considerations in the calculate function since
372      * all we really care about are counters that tell use exactly how
373      * many bytes are in the payload and how many of those bytes to
374      * include from the TDR into the payload.
375      */
376     calculate_N1(s, opcode);
377     trace_pnv_spi_log_Ncounts(s->N1_bits, s->N1_bytes, s->N1_tx,
378                     s->N1_rx, s->N2_bits, s->N2_bytes, s->N2_tx, s->N2_rx);
379     /*
380      * Zero out the N2 counters here in case there is no N2 operation following
381      * the N1 operation in the sequencer.  This keeps leftover N2 information
382      * from interfering with spi_response logic.
383      */
384     s->N2_bits = 0;
385     s->N2_bytes = 0;
386     s->N2_tx = 0;
387     s->N2_rx = 0;
388     /*
389      * N1_bytes is the overall size of the N1 portion of the frame regardless of
390      * whether N1 is used for tx, rx or both.  Loop over the size to build a
391      * payload that is N1_bytes long.
392      * N1_tx is the count of bytes to take from the TDR and "shift" into the
393      * frame which means append those bytes to the payload for the N1 portion
394      * of the frame.
395      * If N1_tx is 0 or if the count exceeds the size of the TDR append 0xFF to
396      * the frame until the overall N1 count is reached.
397      */
398     n1_count = 0;
399     while (n1_count < s->N1_bytes) {
400         /*
401          * Assuming that if N1_tx is not equal to 0 then it is the same as
402          * N1_bytes.
403          */
404         if ((s->N1_tx != 0) && (n1_count < PNV_SPI_REG_SIZE)) {
405 
406             if (GETFIELD(SPI_STS_TDR_FULL, s->status) == 1) {
407                 /*
408                  * Note that we are only appending to the payload IF the TDR
409                  * is full otherwise we don't touch the payload because we are
410                  * going to NOT send the payload and instead tell the sequencer
411                  * that called us to stop and wait for a TDR write so we have
412                  * data to load into the payload.
413                  */
414                 uint8_t n1_byte = 0x00;
415                 n1_byte = get_from_offset(s, n1_count);
416                 trace_pnv_spi_tx_append("n1_byte", n1_byte, n1_count);
417                 *(pnv_spi_xfer_buffer_write_ptr(*payload, (*payload)->len, 1)) =
418                         n1_byte;
419             } else {
420                 /*
421                  * We hit a shift_n1 opcode TX but the TDR is empty, tell the
422                  * sequencer to stop and break this loop.
423                  */
424                 trace_pnv_spi_sequencer_stop_requested("Shift N1"
425                                 "set for transmit but TDR is empty");
426                 stop = true;
427                 break;
428             }
429         } else {
430             /*
431              * Cases here:
432              * - we are receiving during the N1 frame segment and the RDR
433              *   is full so we need to stop until the RDR is read
434              * - we are transmitting and we don't care about RDR status
435              *   since we won't be loading RDR during the frame segment.
436              * - we are receiving and the RDR is empty so we allow the operation
437              *   to proceed.
438              */
439             if ((s->N1_rx != 0) && (GETFIELD(SPI_STS_RDR_FULL,
440                                            s->status) == 1)) {
441                 trace_pnv_spi_sequencer_stop_requested("shift N1"
442                                 "set for receive but RDR is full");
443                 stop = true;
444                 break;
445             } else {
446                 trace_pnv_spi_tx_append_FF("n1_byte");
447                 *(pnv_spi_xfer_buffer_write_ptr(*payload, (*payload)->len, 1))
448                         = 0xff;
449             }
450         }
451         n1_count++;
452     } /* end of while */
453     /*
454      * If we are not stopping due to an empty TDR and we are doing an N1 TX
455      * and the TDR is full we need to clear the TDR_full status.
456      * Do this here instead of up in the loop above so we don't log the message
457      * in every loop iteration.
458      * Ignore the send_n1_alone flag, all that does is defer the TX until the N2
459      * operation, which was found immediately after the current opcode.  The TDR
460      * was unloaded and will be shifted so we have to clear the TDR_full status.
461      */
462     if (!stop && (s->N1_tx != 0) &&
463         (GETFIELD(SPI_STS_TDR_FULL, s->status) == 1)) {
464         s->status = SETFIELD(SPI_STS_TDR_FULL, s->status, 0);
465     }
466     /*
467      * There are other reasons why the shifter would stop, such as a TDR empty
468      * or RDR full condition with N1 set to receive.  If we haven't stopped due
469      * to either one of those conditions then check if the send_n1_alone flag is
470      * equal to False, indicating the next opcode is an N2 operation, AND if
471      * the N2 counter reload switch (bit 0 of the N2 count control field) is
472      * set.  This condition requires a pacing write to "kick" off the N2
473      * shift which includes the N1 shift as well when send_n1_alone is False.
474      */
475     if (!stop && !send_n1_alone &&
476        (GETFIELD(SPI_CTR_CFG_N2_CTRL_B0, s->regs[SPI_CTR_CFG_REG]) == 1)) {
477         trace_pnv_spi_sequencer_stop_requested("N2 counter reload "
478                         "active, stop N1 shift, TDR_underrun set to 1");
479         stop = true;
480         s->status = SETFIELD(SPI_STS_TDR_UNDERRUN, s->status, 1);
481     }
482     /*
483      * If send_n1_alone is set AND we have a full TDR then this is the first and
484      * last payload to send and we don't have an N2 frame segment to add to the
485      * payload.
486      */
487     if (send_n1_alone && !stop) {
488         /* We have a TX and a full TDR or an RX and an empty RDR */
489         trace_pnv_spi_tx_request("Shifting N1 frame", (*payload)->len);
490         transfer(s, *payload);
491         /* The N1 frame shift is complete so reset the N1 counters */
492         s->N2_bits = 0;
493         s->N2_bytes = 0;
494         s->N2_tx = 0;
495         s->N2_rx = 0;
496         pnv_spi_xfer_buffer_free(*payload);
497         *payload = NULL;
498     }
499     return stop;
500 } /* end of operation_shiftn1() */
501 
502 /*
503  * Calculate the N2 counters based on passed in opcode and
504  * internal register values.
505  * The method assumes that the opcode is a Shift_N2 opcode
506  * and doesn't test it.
507  * The counters returned are:
508  * N2 bits: Number of bits in the payload data that are significant
509  * to the responder.
510  * N2_bytes: Total count of payload bytes for the N2 frame.
511  * N2_tx: Total number of bytes taken from TDR for N2
512  * N2_rx: Total number of bytes taken from the payload for N2
513  */
514 static void calculate_N2(PnvSpi *s, uint8_t opcode)
515 {
516     /*
517      * Shift_N2 opcode form: 0x4M
518      * Implicit mode:
519      * If M!=0 the shift count is M bytes and M is the number of rx bytes.
520      * Forced Implicit mode:
521      * M is the shift count but tx and rx is determined by the count control
522      * register fields.  Note that we only check for Forced Implicit mode when
523      * M != 0 since the mode doesn't make sense when M = 0.
524      * Explicit mode:
525      * If M==0 then shift count is number of bits defined in the
526      * Counter Configuration Register's shift_count_N1 field.
527      */
528     if (PNV_SPI_OPCODE_LO_NIBBLE(opcode) == 0) {
529         /* Explicit mode */
530         s->N2_bits = GETFIELD(SPI_CTR_CFG_N2, s->regs[SPI_CTR_CFG_REG]);
531         s->N2_bytes = (s->N2_bits + 7) / 8;
532         s->N2_tx = 0;
533         s->N2_rx = 0;
534         /* If tx count control for N2 is set, load the tx value */
535         if (GETFIELD(SPI_CTR_CFG_N2_CTRL_B2, s->regs[SPI_CTR_CFG_REG]) == 1) {
536             s->N2_tx = s->N2_bytes;
537         }
538         /* If rx count control for N2 is set, load the rx value */
539         if (GETFIELD(SPI_CTR_CFG_N2_CTRL_B3, s->regs[SPI_CTR_CFG_REG]) == 1) {
540             s->N2_rx = s->N2_bytes;
541         }
542     } else {
543         /* Implicit mode/Forced Implicit mode, use M field from opcode */
544         s->N2_bytes = PNV_SPI_OPCODE_LO_NIBBLE(opcode);
545         s->N2_bits = s->N2_bytes * 8;
546         /* Assume that we are going to receive the count */
547         s->N2_rx = s->N2_bytes;
548         s->N2_tx = 0;
549         /* Let Forced Implicit mode have an effect on the counts */
550         if (GETFIELD(SPI_CTR_CFG_N2_CTRL_B1, s->regs[SPI_CTR_CFG_REG]) == 1) {
551             /*
552              * If Forced Implicit mode and count control doesn't
553              * indicate a receive then reset the rx count to 0
554              */
555             if (GETFIELD(SPI_CTR_CFG_N2_CTRL_B3,
556                                     s->regs[SPI_CTR_CFG_REG]) == 0) {
557                 s->N2_rx = 0;
558             }
559             /* If tx count control for N2 is set, load the tx value */
560             if (GETFIELD(SPI_CTR_CFG_N2_CTRL_B2,
561                                     s->regs[SPI_CTR_CFG_REG]) == 1) {
562                 s->N2_tx = s->N2_bytes;
563             }
564         }
565     }
566     /*
567      * Enforce an upper limit on the size of N1 that is equal to the
568      * known size of the shift register, 64 bits or 72 bits if ECC
569      * is enabled.
570      * If the size exceeds 72 bits it is a user error so log an error,
571      * cap the size at a max of 64 bits or 72 bits and set the sequencer FSM
572      * error bit.
573      */
574     uint8_t ecc_control = GETFIELD(SPI_CLK_CFG_ECC_CTRL,
575                     s->regs[SPI_CLK_CFG_REG]);
576     if (ecc_control == 0 || ecc_control == 2) {
577         if (s->N2_bytes > (PNV_SPI_REG_SIZE + 1)) {
578             /* Unsupported N2 shift size when ECC enabled */
579             s->N2_bytes = PNV_SPI_REG_SIZE + 1;
580             s->N2_bits = s->N2_bytes * 8;
581         }
582     } else if (s->N2_bytes > PNV_SPI_REG_SIZE) {
583         /* Unsupported N2 shift size */
584         s->N2_bytes = PNV_SPI_REG_SIZE;
585         s->N2_bits = s->N2_bytes * 8;
586     }
587 } /* end of calculate_N2 */
588 
589 /*
590  * Shift_N2 operation handler method
591  */
592 
593 static bool operation_shiftn2(PnvSpi *s, uint8_t opcode,
594                        PnvXferBuffer **payload)
595 {
596     uint8_t n2_count;
597     bool stop = false;
598 
599     /*
600      * If there isn't a current payload left over from a stopped sequence
601      * create a new one.
602      */
603     if (*payload == NULL) {
604         *payload = pnv_spi_xfer_buffer_new();
605     }
606     /*
607      * Use a combination of N2 counters to build the N2 portion of the
608      * transmit payload.
609      */
610     calculate_N2(s, opcode);
611     trace_pnv_spi_log_Ncounts(s->N1_bits, s->N1_bytes, s->N1_tx,
612                     s->N1_rx, s->N2_bits, s->N2_bytes, s->N2_tx, s->N2_rx);
613     /*
614      * The only difference between this code and the code for shift N1 is
615      * that this code has to account for the possible presence of N1 transmit
616      * bytes already taken from the TDR.
617      * If there are bytes to be transmitted for the N2 portion of the frame
618      * and there are still bytes in TDR that have not been copied into the
619      * TX data of the payload, this code will handle transmitting those
620      * remaining bytes.
621      * If for some reason the transmit count(s) add up to more than the size
622      * of the TDR we will just append 0xFF to the transmit payload data until
623      * the payload is N1 + N2 bytes long.
624      */
625     n2_count = 0;
626     while (n2_count < s->N2_bytes) {
627         /*
628          * If the RDR is full and we need to RX just bail out, letting the
629          * code continue will end up building the payload twice in the same
630          * buffer since RDR full causes a sequence stop and restart.
631          */
632         if ((s->N2_rx != 0) &&
633             (GETFIELD(SPI_STS_RDR_FULL, s->status) == 1)) {
634             trace_pnv_spi_sequencer_stop_requested("shift N2 set"
635                             "for receive but RDR is full");
636             stop = true;
637             break;
638         }
639         if ((s->N2_tx != 0) && ((s->N1_tx + n2_count) <
640                                 PNV_SPI_REG_SIZE)) {
641             /* Always append data for the N2 segment if it is set for TX */
642             uint8_t n2_byte = 0x00;
643             n2_byte = get_from_offset(s, (s->N1_tx + n2_count));
644             trace_pnv_spi_tx_append("n2_byte", n2_byte, (s->N1_tx + n2_count));
645             *(pnv_spi_xfer_buffer_write_ptr(*payload, (*payload)->len, 1))
646                     = n2_byte;
647         } else {
648             /*
649              * Regardless of whether or not N2 is set for TX or RX, we need
650              * the number of bytes in the payload to match the overall length
651              * of the operation.
652              */
653             trace_pnv_spi_tx_append_FF("n2_byte");
654             *(pnv_spi_xfer_buffer_write_ptr(*payload, (*payload)->len, 1))
655                     = 0xff;
656         }
657         n2_count++;
658     } /* end of while */
659     if (!stop) {
660         /* We have a TX and a full TDR or an RX and an empty RDR */
661         trace_pnv_spi_tx_request("Shifting N2 frame", (*payload)->len);
662         transfer(s, *payload);
663         /*
664          * If we are doing an N2 TX and the TDR is full we need to clear the
665          * TDR_full status. Do this here instead of up in the loop above so we
666          * don't log the message in every loop iteration.
667          */
668         if ((s->N2_tx != 0) &&
669             (GETFIELD(SPI_STS_TDR_FULL, s->status) == 1)) {
670             s->status = SETFIELD(SPI_STS_TDR_FULL, s->status, 0);
671         }
672         /*
673          * The N2 frame shift is complete so reset the N2 counters.
674          * Reset the N1 counters also in case the frame was a combination of
675          * N1 and N2 segments.
676          */
677         s->N2_bits = 0;
678         s->N2_bytes = 0;
679         s->N2_tx = 0;
680         s->N2_rx = 0;
681         s->N1_bits = 0;
682         s->N1_bytes = 0;
683         s->N1_tx = 0;
684         s->N1_rx = 0;
685         pnv_spi_xfer_buffer_free(*payload);
686         *payload = NULL;
687     }
688     return stop;
689 } /*  end of operation_shiftn2()*/
690 
691 static void operation_sequencer(PnvSpi *s)
692 {
693     /*
694      * Loop through each sequencer operation ID and perform the requested
695      *  operations.
696      * Flag for indicating if we should send the N1 frame or wait to combine
697      * it with a preceding N2 frame.
698      */
699     bool send_n1_alone = true;
700     bool stop = false; /* Flag to stop the sequencer */
701     uint8_t opcode = 0;
702     uint8_t masked_opcode = 0;
703 
704     /*
705      * PnvXferBuffer for containing the payload of the SPI frame.
706      * This is a static because there are cases where a sequence has to stop
707      * and wait for the target application to unload the RDR.  If this occurs
708      * during a sequence where N1 is not sent alone and instead combined with
709      * N2 since the N1 tx length + the N2 tx length is less than the size of
710      * the TDR.
711      */
712     static PnvXferBuffer *payload;
713 
714     if (payload == NULL) {
715         payload = pnv_spi_xfer_buffer_new();
716     }
717     /*
718      * Clear the sequencer FSM error bit - general_SPI_status[3]
719      * before starting a sequence.
720      */
721     s->status = SETFIELD(SPI_STS_GEN_STATUS_B3, s->status, 0);
722     /*
723      * If the FSM is idle set the sequencer index to 0
724      * (new/restarted sequence)
725      */
726     if (GETFIELD(SPI_STS_SEQ_FSM, s->status) == SEQ_STATE_IDLE) {
727         s->status = SETFIELD(SPI_STS_SEQ_INDEX, s->status, 0);
728     }
729     /*
730      * There are only 8 possible operation IDs to iterate through though
731      * some operations may cause more than one frame to be sequenced.
732      */
733     while (get_seq_index(s) < NUM_SEQ_OPS) {
734         opcode = s->seq_op[get_seq_index(s)];
735         /* Set sequencer state to decode */
736         s->status = SETFIELD(SPI_STS_SEQ_FSM, s->status, SEQ_STATE_DECODE);
737         /*
738          * Only the upper nibble of the operation ID is needed to know what
739          * kind of operation is requested.
740          */
741         masked_opcode = PNV_SPI_MASKED_OPCODE(opcode);
742         switch (masked_opcode) {
743         /*
744          * Increment the operation index in each case instead of just
745          * once at the end in case an operation like the branch
746          * operation needs to change the index.
747          */
748         case SEQ_OP_STOP:
749             s->status = SETFIELD(SPI_STS_SEQ_FSM, s->status, SEQ_STATE_EXECUTE);
750             /* A stop operation in any position stops the sequencer */
751             trace_pnv_spi_sequencer_op("STOP", get_seq_index(s));
752 
753             stop = true;
754             s->status = SETFIELD(SPI_STS_SHIFTER_FSM, s->status, FSM_IDLE);
755             s->loop_counter_1 = 0;
756             s->loop_counter_2 = 0;
757             s->status = SETFIELD(SPI_STS_SEQ_FSM, s->status, SEQ_STATE_IDLE);
758             break;
759 
760         case SEQ_OP_SELECT_SLAVE:
761             s->status = SETFIELD(SPI_STS_SEQ_FSM, s->status, SEQ_STATE_EXECUTE);
762             trace_pnv_spi_sequencer_op("SELECT_SLAVE", get_seq_index(s));
763             /*
764              * This device currently only supports a single responder
765              * connection at position 0.  De-selecting a responder is fine
766              * and expected at the end of a sequence but selecting any
767              * responder other than 0 should cause an error.
768              */
769             s->responder_select = PNV_SPI_OPCODE_LO_NIBBLE(opcode);
770             if (s->responder_select == 0) {
771                 trace_pnv_spi_shifter_done();
772                 qemu_set_irq(s->cs_line[0], 1);
773                 s->status = SETFIELD(SPI_STS_SEQ_INDEX, s->status,
774                                 (get_seq_index(s) + 1));
775                 s->status = SETFIELD(SPI_STS_SHIFTER_FSM, s->status, FSM_DONE);
776             } else if (s->responder_select != 1) {
777                 qemu_log_mask(LOG_GUEST_ERROR, "Slave selection other than 1 "
778                               "not supported, select = 0x%x\n",
779                                s->responder_select);
780                 trace_pnv_spi_sequencer_stop_requested("invalid "
781                                 "responder select");
782                 s->status = SETFIELD(SPI_STS_SHIFTER_FSM, s->status, FSM_IDLE);
783                 stop = true;
784             } else {
785                 /*
786                  * Only allow an FSM_START state when a responder is
787                  * selected
788                  */
789                 s->status = SETFIELD(SPI_STS_SHIFTER_FSM, s->status, FSM_START);
790                 trace_pnv_spi_shifter_stating();
791                 qemu_set_irq(s->cs_line[0], 0);
792                 /*
793                  * A Shift_N2 operation is only valid after a Shift_N1
794                  * according to the spec. The spec doesn't say if that means
795                  * immediately after or just after at any point. We will track
796                  * the occurrence of a Shift_N1 to enforce this requirement in
797                  * the most generic way possible by assuming that the rule
798                  * applies once a valid responder select has occurred.
799                  */
800                 s->shift_n1_done = false;
801                 next_sequencer_fsm(s);
802             }
803             break;
804 
805         case SEQ_OP_SHIFT_N1:
806             s->status = SETFIELD(SPI_STS_SEQ_FSM, s->status, SEQ_STATE_EXECUTE);
807             trace_pnv_spi_sequencer_op("SHIFT_N1", get_seq_index(s));
808             /*
809              * Only allow a shift_n1 when the state is not IDLE or DONE.
810              * In either of those two cases the sequencer is not in a proper
811              * state to perform shift operations because the sequencer has:
812              * - processed a responder deselect (DONE)
813              * - processed a stop opcode (IDLE)
814              * - encountered an error (IDLE)
815              */
816             if ((GETFIELD(SPI_STS_SHIFTER_FSM, s->status) == FSM_IDLE) ||
817                 (GETFIELD(SPI_STS_SHIFTER_FSM, s->status) == FSM_DONE)) {
818                 qemu_log_mask(LOG_GUEST_ERROR, "Shift_N1 not allowed in "
819                               "shifter state = 0x%llx", GETFIELD(
820                         SPI_STS_SHIFTER_FSM, s->status));
821                 /*
822                  * Set sequencer FSM error bit 3 (general_SPI_status[3])
823                  * in status reg.
824                  */
825                 s->status = SETFIELD(SPI_STS_GEN_STATUS_B3, s->status, 1);
826                 trace_pnv_spi_sequencer_stop_requested("invalid shifter state");
827                 stop = true;
828             } else {
829                 /*
830                  * Look for the special case where there is a shift_n1 set for
831                  * transmit and it is followed by a shift_n2 set for transmit
832                  * AND the combined transmit length of the two operations is
833                  * less than or equal to the size of the TDR register. In this
834                  * case we want to use both this current shift_n1 opcode and the
835                  * following shift_n2 opcode to assemble the frame for
836                  * transmission to the responder without requiring a refill of
837                  * the TDR between the two operations.
838                  */
839                 if (PNV_SPI_MASKED_OPCODE(s->seq_op[get_seq_index(s) + 1])
840                                 == SEQ_OP_SHIFT_N2) {
841                     send_n1_alone = false;
842                 }
843                 s->status = SETFIELD(SPI_STS_SHIFTER_FSM, s->status,
844                                 FSM_SHIFT_N1);
845                 stop = operation_shiftn1(s, opcode, &payload, send_n1_alone);
846                 if (stop) {
847                     /*
848                      *  The operation code says to stop, this can occur if:
849                      * (1) RDR is full and the N1 shift is set for receive
850                      * (2) TDR was empty at the time of the N1 shift so we need
851                      * to wait for data.
852                      * (3) Neither 1 nor 2 are occurring and we aren't sending
853                      * N1 alone and N2 counter reload is set (bit 0 of the N2
854                      * counter reload field).  In this case TDR_underrun will
855                      * will be set and the Payload has been loaded so it is
856                      * ok to advance the sequencer.
857                      */
858                     if (GETFIELD(SPI_STS_TDR_UNDERRUN, s->status)) {
859                         s->shift_n1_done = true;
860                         s->status = SETFIELD(SPI_STS_SHIFTER_FSM, s->status,
861                                                   FSM_SHIFT_N2);
862                         s->status = SETFIELD(SPI_STS_SEQ_INDEX, s->status,
863                                         (get_seq_index(s) + 1));
864                     } else {
865                         /*
866                          * This is case (1) or (2) so the sequencer needs to
867                          * wait and NOT go to the next sequence yet.
868                          */
869                         s->status = SETFIELD(SPI_STS_SHIFTER_FSM, s->status,
870                                         FSM_WAIT);
871                     }
872                 } else {
873                     /* Ok to move on to the next index */
874                     s->shift_n1_done = true;
875                     next_sequencer_fsm(s);
876                 }
877             }
878             break;
879 
880         case SEQ_OP_SHIFT_N2:
881             s->status = SETFIELD(SPI_STS_SEQ_FSM, s->status, SEQ_STATE_EXECUTE);
882             trace_pnv_spi_sequencer_op("SHIFT_N2", get_seq_index(s));
883             if (!s->shift_n1_done) {
884                 qemu_log_mask(LOG_GUEST_ERROR, "Shift_N2 is not allowed if a "
885                               "Shift_N1 is not done, shifter state = 0x%llx",
886                               GETFIELD(SPI_STS_SHIFTER_FSM, s->status));
887                 /*
888                  * In case the sequencer actually stops if an N2 shift is
889                  * requested before any N1 shift is done. Set sequencer FSM
890                  * error bit 3 (general_SPI_status[3]) in status reg.
891                  */
892                 s->status = SETFIELD(SPI_STS_GEN_STATUS_B3, s->status, 1);
893                 trace_pnv_spi_sequencer_stop_requested("shift_n2 "
894                                     "w/no shift_n1 done");
895                 stop = true;
896             } else {
897                 /* Ok to do a Shift_N2 */
898                 s->status = SETFIELD(SPI_STS_SHIFTER_FSM, s->status,
899                                 FSM_SHIFT_N2);
900                 stop = operation_shiftn2(s, opcode, &payload);
901                 /*
902                  * If the operation code says to stop set the shifter state to
903                  * wait and stop
904                  */
905                 if (stop) {
906                     s->status = SETFIELD(SPI_STS_SHIFTER_FSM, s->status,
907                                     FSM_WAIT);
908                 } else {
909                     /* Ok to move on to the next index */
910                     next_sequencer_fsm(s);
911                 }
912             }
913             break;
914 
915         case SEQ_OP_BRANCH_IFNEQ_RDR:
916             s->status = SETFIELD(SPI_STS_SEQ_FSM, s->status, SEQ_STATE_EXECUTE);
917             trace_pnv_spi_sequencer_op("BRANCH_IFNEQ_RDR", get_seq_index(s));
918             /*
919              * The memory mapping register RDR match value is compared against
920              * the 16 rightmost bytes of the RDR (potentially with masking).
921              * Since this comparison is performed against the contents of the
922              * RDR then a receive must have previously occurred otherwise
923              * there is no data to compare and the operation cannot be
924              * completed and will stop the sequencer until RDR full is set to
925              * 1.
926              */
927             if (GETFIELD(SPI_STS_RDR_FULL, s->status) == 1) {
928                 bool rdr_matched = false;
929                 rdr_matched = does_rdr_match(s);
930                 if (rdr_matched) {
931                     trace_pnv_spi_RDR_match("success");
932                     /* A match occurred, increment the sequencer index. */
933                     next_sequencer_fsm(s);
934                 } else {
935                     trace_pnv_spi_RDR_match("failed");
936                     /*
937                      * Branch the sequencer to the index coded into the op
938                      * code.
939                      */
940                     s->status = SETFIELD(SPI_STS_SEQ_INDEX, s->status,
941                                     PNV_SPI_OPCODE_LO_NIBBLE(opcode));
942                 }
943                 /*
944                  * Regardless of where the branch ended up we want the
945                  * sequencer to continue shifting so we have to clear
946                  * RDR_full.
947                  */
948                 s->status = SETFIELD(SPI_STS_RDR_FULL, s->status, 0);
949             } else {
950                 trace_pnv_spi_sequencer_stop_requested("RDR not"
951                                 "full for 0x6x opcode");
952                 stop = true;
953                 s->status = SETFIELD(SPI_STS_SHIFTER_FSM, s->status, FSM_WAIT);
954             }
955             break;
956 
957         case SEQ_OP_TRANSFER_TDR:
958             s->status = SETFIELD(SPI_STS_SEQ_FSM, s->status, SEQ_STATE_EXECUTE);
959             qemu_log_mask(LOG_GUEST_ERROR, "Transfer TDR is not supported\n");
960             next_sequencer_fsm(s);
961             break;
962 
963         case SEQ_OP_BRANCH_IFNEQ_INC_1:
964             s->status = SETFIELD(SPI_STS_SEQ_FSM, s->status, SEQ_STATE_EXECUTE);
965             trace_pnv_spi_sequencer_op("BRANCH_IFNEQ_INC_1", get_seq_index(s));
966             /*
967              * The spec says the loop should execute count compare + 1 times.
968              * However we learned from engineering that we really only loop
969              * count_compare times, count compare = 0 makes this op code a
970              * no-op
971              */
972             if (s->loop_counter_1 !=
973                 GETFIELD(SPI_CTR_CFG_CMP1, s->regs[SPI_CTR_CFG_REG])) {
974                 /*
975                  * Next index is the lower nibble of the branch operation ID,
976                  * mask off all but the first three bits so we don't try to
977                  * access beyond the sequencer_operation_reg boundary.
978                  */
979                 s->status = SETFIELD(SPI_STS_SEQ_INDEX, s->status,
980                                 PNV_SPI_OPCODE_LO_NIBBLE(opcode));
981                 s->loop_counter_1++;
982             } else {
983                 /* Continue to next index if loop counter is reached */
984                 next_sequencer_fsm(s);
985             }
986             break;
987 
988         case SEQ_OP_BRANCH_IFNEQ_INC_2:
989             s->status = SETFIELD(SPI_STS_SEQ_FSM, s->status, SEQ_STATE_EXECUTE);
990             trace_pnv_spi_sequencer_op("BRANCH_IFNEQ_INC_2", get_seq_index(s));
991             uint8_t condition2 = GETFIELD(SPI_CTR_CFG_CMP2,
992                               s->regs[SPI_CTR_CFG_REG]);
993             /*
994              * The spec says the loop should execute count compare + 1 times.
995              * However we learned from engineering that we really only loop
996              * count_compare times, count compare = 0 makes this op code a
997              * no-op
998              */
999             if (s->loop_counter_2 != condition2) {
1000                 /*
1001                  * Next index is the lower nibble of the branch operation ID,
1002                  * mask off all but the first three bits so we don't try to
1003                  * access beyond the sequencer_operation_reg boundary.
1004                  */
1005                 s->status = SETFIELD(SPI_STS_SEQ_INDEX,
1006                                 s->status, PNV_SPI_OPCODE_LO_NIBBLE(opcode));
1007                 s->loop_counter_2++;
1008             } else {
1009                 /* Continue to next index if loop counter is reached */
1010                 next_sequencer_fsm(s);
1011             }
1012             break;
1013 
1014         default:
1015             s->status = SETFIELD(SPI_STS_SEQ_FSM, s->status, SEQ_STATE_EXECUTE);
1016             /* Ignore unsupported operations. */
1017             next_sequencer_fsm(s);
1018             break;
1019         } /* end of switch */
1020         /*
1021          * If we used all 8 opcodes without seeing a 00 - STOP in the sequence
1022          * we need to go ahead and end things as if there was a STOP at the
1023          * end.
1024          */
1025         if (get_seq_index(s) == NUM_SEQ_OPS) {
1026             /* All 8 opcodes completed, sequencer idling */
1027             s->status = SETFIELD(SPI_STS_SHIFTER_FSM, s->status, FSM_IDLE);
1028             s->status = SETFIELD(SPI_STS_SEQ_INDEX, s->status, 0);
1029             s->loop_counter_1 = 0;
1030             s->loop_counter_2 = 0;
1031             s->status = SETFIELD(SPI_STS_SEQ_FSM, s->status, SEQ_STATE_IDLE);
1032             break;
1033         }
1034         /* Break the loop if a stop was requested */
1035         if (stop) {
1036             break;
1037         }
1038     } /* end of while */
1039     return;
1040 } /* end of operation_sequencer() */
1041 
1042 /*
1043  * The SPIC engine and its internal sequencer can be interrupted and reset by
1044  * a hardware signal, the sbe_spicst_hard_reset bits from Pervasive
1045  * Miscellaneous Register of sbe_register_bo device.
1046  * Reset immediately aborts any SPI transaction in progress and returns the
1047  * sequencer and state machines to idle state.
1048  * The configuration register values are not changed. The status register is
1049  * not reset. The engine registers are not reset.
1050  * The SPIC engine reset does not have any affect on the attached devices.
1051  * Reset handling of any attached devices is beyond the scope of the engine.
1052  */
1053 static void do_reset(DeviceState *dev)
1054 {
1055     PnvSpi *s = PNV_SPI(dev);
1056     DeviceState *ssi_dev;
1057 
1058     trace_pnv_spi_reset();
1059 
1060     /* Connect cs irq */
1061     ssi_dev = ssi_get_cs(s->ssi_bus, 0);
1062     if (ssi_dev) {
1063         qemu_irq cs_line = qdev_get_gpio_in_named(ssi_dev, SSI_GPIO_CS, 0);
1064         qdev_connect_gpio_out_named(DEVICE(s), "cs", 0, cs_line);
1065     }
1066 
1067     /* Reset all N1 and N2 counters, and other constants */
1068     s->N2_bits = 0;
1069     s->N2_bytes = 0;
1070     s->N2_tx = 0;
1071     s->N2_rx = 0;
1072     s->N1_bits = 0;
1073     s->N1_bytes = 0;
1074     s->N1_tx = 0;
1075     s->N1_rx = 0;
1076     s->loop_counter_1 = 0;
1077     s->loop_counter_2 = 0;
1078     /* Disconnected from responder */
1079     qemu_set_irq(s->cs_line[0], 1);
1080 }
1081 
1082 static uint64_t pnv_spi_xscom_read(void *opaque, hwaddr addr, unsigned size)
1083 {
1084     PnvSpi *s = PNV_SPI(opaque);
1085     uint32_t reg = addr >> 3;
1086     uint64_t val = ~0ull;
1087 
1088     switch (reg) {
1089     case ERROR_REG:
1090     case SPI_CTR_CFG_REG:
1091     case CONFIG_REG1:
1092     case SPI_CLK_CFG_REG:
1093     case SPI_MM_REG:
1094     case SPI_XMIT_DATA_REG:
1095         val = s->regs[reg];
1096         break;
1097     case SPI_RCV_DATA_REG:
1098         val = s->regs[reg];
1099         trace_pnv_spi_read_RDR(val);
1100         s->status = SETFIELD(SPI_STS_RDR_FULL, s->status, 0);
1101         if (GETFIELD(SPI_STS_SHIFTER_FSM, s->status) == FSM_WAIT) {
1102             trace_pnv_spi_start_sequencer();
1103             operation_sequencer(s);
1104         }
1105         break;
1106     case SPI_SEQ_OP_REG:
1107         val = 0;
1108         for (int i = 0; i < PNV_SPI_REG_SIZE; i++) {
1109             val = (val << 8) | s->seq_op[i];
1110         }
1111         break;
1112     case SPI_STS_REG:
1113         val = s->status;
1114         break;
1115     default:
1116         qemu_log_mask(LOG_GUEST_ERROR, "pnv_spi_regs: Invalid xscom "
1117                  "read at 0x%" PRIx32 "\n", reg);
1118     }
1119 
1120     trace_pnv_spi_read(addr, val);
1121     return val;
1122 }
1123 
1124 static void pnv_spi_xscom_write(void *opaque, hwaddr addr,
1125                                  uint64_t val, unsigned size)
1126 {
1127     PnvSpi *s = PNV_SPI(opaque);
1128     uint32_t reg = addr >> 3;
1129 
1130     trace_pnv_spi_write(addr, val);
1131 
1132     switch (reg) {
1133     case ERROR_REG:
1134     case SPI_CTR_CFG_REG:
1135     case CONFIG_REG1:
1136     case SPI_MM_REG:
1137     case SPI_RCV_DATA_REG:
1138         s->regs[reg] = val;
1139         break;
1140     case SPI_CLK_CFG_REG:
1141         /*
1142          * To reset the SPI controller write the sequence 0x5 0xA to
1143          * reset_control field
1144          */
1145         if ((GETFIELD(SPI_CLK_CFG_RST_CTRL, s->regs[SPI_CLK_CFG_REG]) == 0x5)
1146              && (GETFIELD(SPI_CLK_CFG_RST_CTRL, val) == 0xA)) {
1147                 /* SPI controller reset sequence completed, resetting */
1148             s->regs[reg] = SPI_CLK_CFG_HARD_RST;
1149         } else {
1150             s->regs[reg] = val;
1151         }
1152         break;
1153     case SPI_XMIT_DATA_REG:
1154         /*
1155          * Writing to the transmit data register causes the transmit data
1156          * register full status bit in the status register to be set.  Writing
1157          * when the transmit data register full status bit is already set
1158          * causes a "Resource Not Available" condition.  This is not possible
1159          * in the model since writes to this register are not asynchronous to
1160          * the operation sequence like it would be in hardware.
1161          */
1162         s->regs[reg] = val;
1163         trace_pnv_spi_write_TDR(val);
1164         s->status = SETFIELD(SPI_STS_TDR_FULL, s->status, 1);
1165         s->status = SETFIELD(SPI_STS_TDR_UNDERRUN, s->status, 0);
1166         trace_pnv_spi_start_sequencer();
1167         operation_sequencer(s);
1168         break;
1169     case SPI_SEQ_OP_REG:
1170         for (int i = 0; i < PNV_SPI_REG_SIZE; i++) {
1171             s->seq_op[i] = (val >> (56 - i * 8)) & 0xFF;
1172         }
1173         break;
1174     case SPI_STS_REG:
1175         /* other fields are ignore_write */
1176         s->status = SETFIELD(SPI_STS_RDR_OVERRUN, s->status,
1177                                   GETFIELD(SPI_STS_RDR, val));
1178         s->status = SETFIELD(SPI_STS_TDR_OVERRUN, s->status,
1179                                   GETFIELD(SPI_STS_TDR, val));
1180         break;
1181     default:
1182         qemu_log_mask(LOG_GUEST_ERROR, "pnv_spi_regs: Invalid xscom "
1183                  "write at 0x%" PRIx32 "\n", reg);
1184     }
1185     return;
1186 }
1187 
1188 static const MemoryRegionOps pnv_spi_xscom_ops = {
1189     .read = pnv_spi_xscom_read,
1190     .write = pnv_spi_xscom_write,
1191     .valid.min_access_size = 8,
1192     .valid.max_access_size = 8,
1193     .impl.min_access_size = 8,
1194     .impl.max_access_size = 8,
1195     .endianness = DEVICE_BIG_ENDIAN,
1196 };
1197 
1198 static Property pnv_spi_properties[] = {
1199     DEFINE_PROP_UINT32("spic_num", PnvSpi, spic_num, 0),
1200     DEFINE_PROP_UINT8("transfer_len", PnvSpi, transfer_len, 4),
1201     DEFINE_PROP_END_OF_LIST(),
1202 };
1203 
1204 static void pnv_spi_realize(DeviceState *dev, Error **errp)
1205 {
1206     PnvSpi *s = PNV_SPI(dev);
1207     g_autofree char *name = g_strdup_printf(TYPE_PNV_SPI_BUS ".%d",
1208                     s->spic_num);
1209     s->ssi_bus = ssi_create_bus(dev, name);
1210     s->cs_line = g_new0(qemu_irq, 1);
1211     qdev_init_gpio_out_named(DEVICE(s), s->cs_line, "cs", 1);
1212 
1213     /* spi scoms */
1214     pnv_xscom_region_init(&s->xscom_spic_regs, OBJECT(s), &pnv_spi_xscom_ops,
1215                           s, "xscom-spi", PNV10_XSCOM_PIB_SPIC_SIZE);
1216 }
1217 
1218 static int pnv_spi_dt_xscom(PnvXScomInterface *dev, void *fdt,
1219                              int offset)
1220 {
1221     PnvSpi *s = PNV_SPI(dev);
1222     g_autofree char *name;
1223     int s_offset;
1224     const char compat[] = "ibm,power10-spi";
1225     uint32_t spic_pcba = PNV10_XSCOM_PIB_SPIC_BASE +
1226         s->spic_num * PNV10_XSCOM_PIB_SPIC_SIZE;
1227     uint32_t reg[] = {
1228         cpu_to_be32(spic_pcba),
1229         cpu_to_be32(PNV10_XSCOM_PIB_SPIC_SIZE)
1230     };
1231     name = g_strdup_printf("pnv_spi@%x", spic_pcba);
1232     s_offset = fdt_add_subnode(fdt, offset, name);
1233     _FDT(s_offset);
1234 
1235     _FDT(fdt_setprop(fdt, s_offset, "reg", reg, sizeof(reg)));
1236     _FDT(fdt_setprop(fdt, s_offset, "compatible", compat, sizeof(compat)));
1237     _FDT((fdt_setprop_cell(fdt, s_offset, "spic_num#", s->spic_num)));
1238     return 0;
1239 }
1240 
1241 static void pnv_spi_class_init(ObjectClass *klass, void *data)
1242 {
1243     DeviceClass *dc = DEVICE_CLASS(klass);
1244     PnvXScomInterfaceClass *xscomc = PNV_XSCOM_INTERFACE_CLASS(klass);
1245 
1246     xscomc->dt_xscom = pnv_spi_dt_xscom;
1247 
1248     dc->desc = "PowerNV SPI";
1249     dc->realize = pnv_spi_realize;
1250     dc->reset = do_reset;
1251     device_class_set_props(dc, pnv_spi_properties);
1252 }
1253 
1254 static const TypeInfo pnv_spi_info = {
1255     .name          = TYPE_PNV_SPI,
1256     .parent        = TYPE_SYS_BUS_DEVICE,
1257     .instance_size = sizeof(PnvSpi),
1258     .class_init    = pnv_spi_class_init,
1259     .interfaces    = (InterfaceInfo[]) {
1260         { TYPE_PNV_XSCOM_INTERFACE },
1261         { }
1262     }
1263 };
1264 
1265 static void pnv_spi_register_types(void)
1266 {
1267     type_register_static(&pnv_spi_info);
1268 }
1269 
1270 type_init(pnv_spi_register_types);
1271