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ths663e8e52007-04-02 12:35:34 +00001/*
2 * QEMU EEPROM 93xx emulation
3 *
4 * Copyright (c) 2006-2007 Stefan Weil
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
Blue Swirl8167ee82009-07-16 20:47:01 +000017 * along with this program; if not, see <http://www.gnu.org/licenses/>.
ths663e8e52007-04-02 12:35:34 +000018 */
19
20/* Emulation for serial EEPROMs:
21 * NMC93C06 256-Bit (16 x 16)
22 * NMC93C46 1024-Bit (64 x 16)
23 * NMC93C56 2028 Bit (128 x 16)
24 * NMC93C66 4096 Bit (256 x 16)
25 * Compatible devices include FM93C46 and others.
26 *
27 * Other drivers use these interface functions:
28 * eeprom93xx_new - add a new EEPROM (with 16, 64 or 256 words)
29 * eeprom93xx_free - destroy EEPROM
30 * eeprom93xx_read - read data from the EEPROM
31 * eeprom93xx_write - write data to the EEPROM
32 * eeprom93xx_data - get EEPROM data array for external manipulation
33 *
34 * Todo list:
35 * - No emulation of EEPROM timings.
36 */
37
Peter Maydell04308912016-01-26 18:17:30 +000038#include "qemu/osdep.h"
Paolo Bonzini0d09e412013-02-05 17:06:20 +010039#include "hw/nvram/eeprom93xx.h"
Markus Armbrusterca77ee22019-08-12 07:23:39 +020040#include "migration/qemu-file-types.h"
Markus Armbrusterd6454272019-08-12 07:23:45 +020041#include "migration/vmstate.h"
ths663e8e52007-04-02 12:35:34 +000042
43/* Debug EEPROM emulation. */
44//~ #define DEBUG_EEPROM
45
46#ifdef DEBUG_EEPROM
Blue Swirl001faf32009-05-13 17:53:17 +000047#define logout(fmt, ...) fprintf(stderr, "EEPROM\t%-24s" fmt, __func__, ## __VA_ARGS__)
ths663e8e52007-04-02 12:35:34 +000048#else
Blue Swirl001faf32009-05-13 17:53:17 +000049#define logout(fmt, ...) ((void)0)
ths663e8e52007-04-02 12:35:34 +000050#endif
51
aurel327ab25892009-03-28 23:14:52 +000052#define EEPROM_INSTANCE 0
53#define OLD_EEPROM_VERSION 20061112
54#define EEPROM_VERSION (OLD_EEPROM_VERSION + 1)
ths663e8e52007-04-02 12:35:34 +000055
56#if 0
57typedef enum {
58 eeprom_read = 0x80, /* read register xx */
59 eeprom_write = 0x40, /* write register xx */
60 eeprom_erase = 0xc0, /* erase register xx */
61 eeprom_ewen = 0x30, /* erase / write enable */
62 eeprom_ewds = 0x00, /* erase / write disable */
63 eeprom_eral = 0x20, /* erase all registers */
64 eeprom_wral = 0x10, /* write all registers */
65 eeprom_amask = 0x0f,
66 eeprom_imask = 0xf0
67} eeprom_instruction_t;
68#endif
69
70#ifdef DEBUG_EEPROM
71static const char *opstring[] = {
72 "extended", "write", "read", "erase"
73};
74#endif
75
Anthony Liguoric227f092009-10-01 16:12:16 -050076struct _eeprom_t {
ths663e8e52007-04-02 12:35:34 +000077 uint8_t tick;
78 uint8_t address;
79 uint8_t command;
Stefan Weilebabb672011-04-26 10:29:36 +020080 uint8_t writable;
ths663e8e52007-04-02 12:35:34 +000081
82 uint8_t eecs;
83 uint8_t eesk;
84 uint8_t eedo;
85
86 uint8_t addrbits;
aurel327ab25892009-03-28 23:14:52 +000087 uint16_t size;
ths663e8e52007-04-02 12:35:34 +000088 uint16_t data;
Philippe Mathieu-Daudéf7795e42020-03-04 16:38:15 +010089 uint16_t contents[];
ths663e8e52007-04-02 12:35:34 +000090};
91
92/* Code for saving and restoring of EEPROM state. */
93
Juan Quintelac4a0f2d2009-10-16 12:13:53 +020094/* Restore an uint16_t from an uint8_t
95 This is a Big hack, but it is how the old state did it.
96 */
97
Jianjun Duan2c21ee72017-01-19 11:00:50 -080098static int get_uint16_from_uint8(QEMUFile *f, void *pv, size_t size,
Marc-André Lureau03fee662018-11-14 17:29:30 +040099 const VMStateField *field)
ths663e8e52007-04-02 12:35:34 +0000100{
Juan Quintelac4a0f2d2009-10-16 12:13:53 +0200101 uint16_t *v = pv;
102 *v = qemu_get_ubyte(f);
103 return 0;
ths663e8e52007-04-02 12:35:34 +0000104}
105
Marc-André Lureau03fee662018-11-14 17:29:30 +0400106static int put_unused(QEMUFile *f, void *pv, size_t size,
Markus Armbruster3ddba9a2020-12-11 18:11:48 +0100107 const VMStateField *field, JSONWriter *vmdesc)
ths663e8e52007-04-02 12:35:34 +0000108{
Juan Quintelac4a0f2d2009-10-16 12:13:53 +0200109 fprintf(stderr, "uint16_from_uint8 is used only for backwards compatibility.\n");
110 fprintf(stderr, "Never should be used to write a new state.\n");
111 exit(0);
Jianjun Duan2c21ee72017-01-19 11:00:50 -0800112
113 return 0;
ths663e8e52007-04-02 12:35:34 +0000114}
115
Blue Swirld05ac8f2009-12-04 20:44:44 +0000116static const VMStateInfo vmstate_hack_uint16_from_uint8 = {
Juan Quintelac4a0f2d2009-10-16 12:13:53 +0200117 .name = "uint16_from_uint8",
118 .get = get_uint16_from_uint8,
119 .put = put_unused,
120};
121
122#define VMSTATE_UINT16_HACK_TEST(_f, _s, _t) \
123 VMSTATE_SINGLE_TEST(_f, _s, _t, 0, vmstate_hack_uint16_from_uint8, uint16_t)
124
125static bool is_old_eeprom_version(void *opaque, int version_id)
126{
127 return version_id == OLD_EEPROM_VERSION;
128}
129
130static const VMStateDescription vmstate_eeprom = {
131 .name = "eeprom",
132 .version_id = EEPROM_VERSION,
133 .minimum_version_id = OLD_EEPROM_VERSION,
Juan Quintelad49805a2014-04-16 15:32:32 +0200134 .fields = (VMStateField[]) {
Juan Quintelac4a0f2d2009-10-16 12:13:53 +0200135 VMSTATE_UINT8(tick, eeprom_t),
136 VMSTATE_UINT8(address, eeprom_t),
137 VMSTATE_UINT8(command, eeprom_t),
Stefan Weilebabb672011-04-26 10:29:36 +0200138 VMSTATE_UINT8(writable, eeprom_t),
Juan Quintelac4a0f2d2009-10-16 12:13:53 +0200139
140 VMSTATE_UINT8(eecs, eeprom_t),
141 VMSTATE_UINT8(eesk, eeprom_t),
142 VMSTATE_UINT8(eedo, eeprom_t),
143
144 VMSTATE_UINT8(addrbits, eeprom_t),
145 VMSTATE_UINT16_HACK_TEST(size, eeprom_t, is_old_eeprom_version),
146 VMSTATE_UNUSED_TEST(is_old_eeprom_version, 1),
Halil Pasicd2164ad2017-06-23 16:48:23 +0200147 VMSTATE_UINT16_EQUAL_V(size, eeprom_t, EEPROM_VERSION, NULL),
Juan Quintelac4a0f2d2009-10-16 12:13:53 +0200148 VMSTATE_UINT16(data, eeprom_t),
149 VMSTATE_VARRAY_UINT16_UNSAFE(contents, eeprom_t, size, 0,
150 vmstate_info_uint16, uint16_t),
151 VMSTATE_END_OF_LIST()
152 }
153};
154
Anthony Liguoric227f092009-10-01 16:12:16 -0500155void eeprom93xx_write(eeprom_t *eeprom, int eecs, int eesk, int eedi)
ths663e8e52007-04-02 12:35:34 +0000156{
157 uint8_t tick = eeprom->tick;
158 uint8_t eedo = eeprom->eedo;
159 uint16_t address = eeprom->address;
160 uint8_t command = eeprom->command;
161
162 logout("CS=%u SK=%u DI=%u DO=%u, tick = %u\n",
163 eecs, eesk, eedi, eedo, tick);
164
Antony Pavlov6fedcaa2013-12-04 10:27:29 +0400165 if (!eeprom->eecs && eecs) {
ths663e8e52007-04-02 12:35:34 +0000166 /* Start chip select cycle. */
167 logout("Cycle start, waiting for 1st start bit (0)\n");
168 tick = 0;
169 command = 0x0;
170 address = 0x0;
Antony Pavlov6fedcaa2013-12-04 10:27:29 +0400171 } else if (eeprom->eecs && !eecs) {
ths663e8e52007-04-02 12:35:34 +0000172 /* End chip select cycle. This triggers write / erase. */
Stefan Weilebabb672011-04-26 10:29:36 +0200173 if (eeprom->writable) {
ths663e8e52007-04-02 12:35:34 +0000174 uint8_t subcommand = address >> (eeprom->addrbits - 2);
175 if (command == 0 && subcommand == 2) {
176 /* Erase all. */
177 for (address = 0; address < eeprom->size; address++) {
178 eeprom->contents[address] = 0xffff;
179 }
180 } else if (command == 3) {
181 /* Erase word. */
182 eeprom->contents[address] = 0xffff;
183 } else if (tick >= 2 + 2 + eeprom->addrbits + 16) {
184 if (command == 1) {
185 /* Write word. */
186 eeprom->contents[address] &= eeprom->data;
187 } else if (command == 0 && subcommand == 1) {
188 /* Write all. */
189 for (address = 0; address < eeprom->size; address++) {
190 eeprom->contents[address] &= eeprom->data;
191 }
192 }
193 }
194 }
195 /* Output DO is tristate, read results in 1. */
196 eedo = 1;
Antony Pavlov6fedcaa2013-12-04 10:27:29 +0400197 } else if (eecs && !eeprom->eesk && eesk) {
ths663e8e52007-04-02 12:35:34 +0000198 /* Raising edge of clock shifts data in. */
199 if (tick == 0) {
200 /* Wait for 1st start bit. */
201 if (eedi == 0) {
202 logout("Got correct 1st start bit, waiting for 2nd start bit (1)\n");
203 tick++;
204 } else {
205 logout("wrong 1st start bit (is 1, should be 0)\n");
206 tick = 2;
207 //~ assert(!"wrong start bit");
208 }
209 } else if (tick == 1) {
210 /* Wait for 2nd start bit. */
211 if (eedi != 0) {
212 logout("Got correct 2nd start bit, getting command + address\n");
213 tick++;
214 } else {
215 logout("1st start bit is longer than needed\n");
216 }
217 } else if (tick < 2 + 2) {
218 /* Got 2 start bits, transfer 2 opcode bits. */
219 tick++;
220 command <<= 1;
221 if (eedi) {
222 command += 1;
223 }
224 } else if (tick < 2 + 2 + eeprom->addrbits) {
225 /* Got 2 start bits and 2 opcode bits, transfer all address bits. */
226 tick++;
227 address = ((address << 1) | eedi);
228 if (tick == 2 + 2 + eeprom->addrbits) {
229 logout("%s command, address = 0x%02x (value 0x%04x)\n",
230 opstring[command], address, eeprom->contents[address]);
231 if (command == 2) {
232 eedo = 0;
233 }
234 address = address % eeprom->size;
235 if (command == 0) {
236 /* Command code in upper 2 bits of address. */
237 switch (address >> (eeprom->addrbits - 2)) {
Antony Pavlov6fedcaa2013-12-04 10:27:29 +0400238 case 0:
239 logout("write disable command\n");
240 eeprom->writable = 0;
241 break;
242 case 1:
243 logout("write all command\n");
244 break;
245 case 2:
246 logout("erase all command\n");
247 break;
248 case 3:
249 logout("write enable command\n");
250 eeprom->writable = 1;
251 break;
ths663e8e52007-04-02 12:35:34 +0000252 }
253 } else {
254 /* Read, write or erase word. */
255 eeprom->data = eeprom->contents[address];
256 }
257 }
258 } else if (tick < 2 + 2 + eeprom->addrbits + 16) {
259 /* Transfer 16 data bits. */
260 tick++;
261 if (command == 2) {
262 /* Read word. */
263 eedo = ((eeprom->data & 0x8000) != 0);
264 }
265 eeprom->data <<= 1;
266 eeprom->data += eedi;
267 } else {
268 logout("additional unneeded tick, not processed\n");
269 }
270 }
271 /* Save status of EEPROM. */
272 eeprom->tick = tick;
273 eeprom->eecs = eecs;
274 eeprom->eesk = eesk;
275 eeprom->eedo = eedo;
276 eeprom->address = address;
277 eeprom->command = command;
278}
279
Anthony Liguoric227f092009-10-01 16:12:16 -0500280uint16_t eeprom93xx_read(eeprom_t *eeprom)
ths663e8e52007-04-02 12:35:34 +0000281{
282 /* Return status of pin DO (0 or 1). */
283 logout("CS=%u DO=%u\n", eeprom->eecs, eeprom->eedo);
Antony Pavlov6fedcaa2013-12-04 10:27:29 +0400284 return eeprom->eedo;
ths663e8e52007-04-02 12:35:34 +0000285}
286
287#if 0
288void eeprom93xx_reset(eeprom_t *eeprom)
289{
290 /* prepare eeprom */
291 logout("eeprom = 0x%p\n", eeprom);
292 eeprom->tick = 0;
293 eeprom->command = 0;
294}
295#endif
296
Alex Williamson5fce2b32010-06-25 11:09:21 -0600297eeprom_t *eeprom93xx_new(DeviceState *dev, uint16_t nwords)
ths663e8e52007-04-02 12:35:34 +0000298{
299 /* Add a new EEPROM (with 16, 64 or 256 words). */
Anthony Liguoric227f092009-10-01 16:12:16 -0500300 eeprom_t *eeprom;
ths663e8e52007-04-02 12:35:34 +0000301 uint8_t addrbits;
302
303 switch (nwords) {
Antony Pavlov6fedcaa2013-12-04 10:27:29 +0400304 case 16:
305 case 64:
306 addrbits = 6;
307 break;
308 case 128:
309 case 256:
310 addrbits = 8;
311 break;
312 default:
313 assert(!"Unsupported EEPROM size, fallback to 64 words!");
314 nwords = 64;
315 addrbits = 6;
ths663e8e52007-04-02 12:35:34 +0000316 }
317
Markus Armbruster0a553c12022-09-23 14:00:24 +0200318 eeprom = g_malloc0(sizeof(*eeprom) + nwords * 2);
ths663e8e52007-04-02 12:35:34 +0000319 eeprom->size = nwords;
320 eeprom->addrbits = addrbits;
321 /* Output DO is tristate, read results in 1. */
322 eeprom->eedo = 1;
323 logout("eeprom = 0x%p, nwords = %u\n", eeprom, nwords);
Juan Quintela7769fb82023-10-20 11:07:30 +0200324 vmstate_register_any(VMSTATE_IF(dev), &vmstate_eeprom, eeprom);
ths663e8e52007-04-02 12:35:34 +0000325 return eeprom;
326}
327
Alex Williamson5fce2b32010-06-25 11:09:21 -0600328void eeprom93xx_free(DeviceState *dev, eeprom_t *eeprom)
ths663e8e52007-04-02 12:35:34 +0000329{
330 /* Destroy EEPROM. */
331 logout("eeprom = 0x%p\n", eeprom);
Marc-André Lureau3cad4052019-08-28 16:02:32 +0400332 vmstate_unregister(VMSTATE_IF(dev), &vmstate_eeprom, eeprom);
Anthony Liguori7267c092011-08-20 22:09:37 -0500333 g_free(eeprom);
ths663e8e52007-04-02 12:35:34 +0000334}
335
Anthony Liguoric227f092009-10-01 16:12:16 -0500336uint16_t *eeprom93xx_data(eeprom_t *eeprom)
ths663e8e52007-04-02 12:35:34 +0000337{
338 /* Get EEPROM data array. */
339 return &eeprom->contents[0];
340}
341
342/* eof */