2
* QEMU EEPROM 93xx emulation
4
* Copyright (c) 2006-2007 Stefan Weil
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.
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.
16
* You should have received a copy of the GNU General Public License
17
* along with this program; if not, see <http://www.gnu.org/licenses/>.
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.
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
35
* - No emulation of EEPROM timings.
39
#include "eeprom93xx.h"
41
/* Debug EEPROM emulation. */
42
//~ #define DEBUG_EEPROM
45
#define logout(fmt, ...) fprintf(stderr, "EEPROM\t%-24s" fmt, __func__, ## __VA_ARGS__)
47
#define logout(fmt, ...) ((void)0)
50
#define EEPROM_INSTANCE 0
51
#define OLD_EEPROM_VERSION 20061112
52
#define EEPROM_VERSION (OLD_EEPROM_VERSION + 1)
56
eeprom_read = 0x80, /* read register xx */
57
eeprom_write = 0x40, /* write register xx */
58
eeprom_erase = 0xc0, /* erase register xx */
59
eeprom_ewen = 0x30, /* erase / write enable */
60
eeprom_ewds = 0x00, /* erase / write disable */
61
eeprom_eral = 0x20, /* erase all registers */
62
eeprom_wral = 0x10, /* write all registers */
65
} eeprom_instruction_t;
69
static const char *opstring[] = {
70
"extended", "write", "read", "erase"
90
/* Code for saving and restoring of EEPROM state. */
92
/* Restore an uint16_t from an uint8_t
93
This is a Big hack, but it is how the old state did it.
96
static int get_uint16_from_uint8(QEMUFile *f, void *pv, size_t size)
99
*v = qemu_get_ubyte(f);
103
static void put_unused(QEMUFile *f, void *pv, size_t size)
105
fprintf(stderr, "uint16_from_uint8 is used only for backwards compatibility.\n");
106
fprintf(stderr, "Never should be used to write a new state.\n");
110
static const VMStateInfo vmstate_hack_uint16_from_uint8 = {
111
.name = "uint16_from_uint8",
112
.get = get_uint16_from_uint8,
116
#define VMSTATE_UINT16_HACK_TEST(_f, _s, _t) \
117
VMSTATE_SINGLE_TEST(_f, _s, _t, 0, vmstate_hack_uint16_from_uint8, uint16_t)
119
static bool is_old_eeprom_version(void *opaque, int version_id)
121
return version_id == OLD_EEPROM_VERSION;
124
static const VMStateDescription vmstate_eeprom = {
126
.version_id = EEPROM_VERSION,
127
.minimum_version_id = OLD_EEPROM_VERSION,
128
.minimum_version_id_old = OLD_EEPROM_VERSION,
129
.fields = (VMStateField []) {
130
VMSTATE_UINT8(tick, eeprom_t),
131
VMSTATE_UINT8(address, eeprom_t),
132
VMSTATE_UINT8(command, eeprom_t),
133
VMSTATE_UINT8(writable, eeprom_t),
135
VMSTATE_UINT8(eecs, eeprom_t),
136
VMSTATE_UINT8(eesk, eeprom_t),
137
VMSTATE_UINT8(eedo, eeprom_t),
139
VMSTATE_UINT8(addrbits, eeprom_t),
140
VMSTATE_UINT16_HACK_TEST(size, eeprom_t, is_old_eeprom_version),
141
VMSTATE_UNUSED_TEST(is_old_eeprom_version, 1),
142
VMSTATE_UINT16_EQUAL_V(size, eeprom_t, EEPROM_VERSION),
143
VMSTATE_UINT16(data, eeprom_t),
144
VMSTATE_VARRAY_UINT16_UNSAFE(contents, eeprom_t, size, 0,
145
vmstate_info_uint16, uint16_t),
146
VMSTATE_END_OF_LIST()
150
void eeprom93xx_write(eeprom_t *eeprom, int eecs, int eesk, int eedi)
152
uint8_t tick = eeprom->tick;
153
uint8_t eedo = eeprom->eedo;
154
uint16_t address = eeprom->address;
155
uint8_t command = eeprom->command;
157
logout("CS=%u SK=%u DI=%u DO=%u, tick = %u\n",
158
eecs, eesk, eedi, eedo, tick);
160
if (! eeprom->eecs && eecs) {
161
/* Start chip select cycle. */
162
logout("Cycle start, waiting for 1st start bit (0)\n");
166
} else if (eeprom->eecs && ! eecs) {
167
/* End chip select cycle. This triggers write / erase. */
168
if (eeprom->writable) {
169
uint8_t subcommand = address >> (eeprom->addrbits - 2);
170
if (command == 0 && subcommand == 2) {
172
for (address = 0; address < eeprom->size; address++) {
173
eeprom->contents[address] = 0xffff;
175
} else if (command == 3) {
177
eeprom->contents[address] = 0xffff;
178
} else if (tick >= 2 + 2 + eeprom->addrbits + 16) {
181
eeprom->contents[address] &= eeprom->data;
182
} else if (command == 0 && subcommand == 1) {
184
for (address = 0; address < eeprom->size; address++) {
185
eeprom->contents[address] &= eeprom->data;
190
/* Output DO is tristate, read results in 1. */
192
} else if (eecs && ! eeprom->eesk && eesk) {
193
/* Raising edge of clock shifts data in. */
195
/* Wait for 1st start bit. */
197
logout("Got correct 1st start bit, waiting for 2nd start bit (1)\n");
200
logout("wrong 1st start bit (is 1, should be 0)\n");
202
//~ assert(!"wrong start bit");
204
} else if (tick == 1) {
205
/* Wait for 2nd start bit. */
207
logout("Got correct 2nd start bit, getting command + address\n");
210
logout("1st start bit is longer than needed\n");
212
} else if (tick < 2 + 2) {
213
/* Got 2 start bits, transfer 2 opcode bits. */
219
} else if (tick < 2 + 2 + eeprom->addrbits) {
220
/* Got 2 start bits and 2 opcode bits, transfer all address bits. */
222
address = ((address << 1) | eedi);
223
if (tick == 2 + 2 + eeprom->addrbits) {
224
logout("%s command, address = 0x%02x (value 0x%04x)\n",
225
opstring[command], address, eeprom->contents[address]);
229
address = address % eeprom->size;
231
/* Command code in upper 2 bits of address. */
232
switch (address >> (eeprom->addrbits - 2)) {
234
logout("write disable command\n");
235
eeprom->writable = 0;
238
logout("write all command\n");
241
logout("erase all command\n");
244
logout("write enable command\n");
245
eeprom->writable = 1;
249
/* Read, write or erase word. */
250
eeprom->data = eeprom->contents[address];
253
} else if (tick < 2 + 2 + eeprom->addrbits + 16) {
254
/* Transfer 16 data bits. */
258
eedo = ((eeprom->data & 0x8000) != 0);
261
eeprom->data += eedi;
263
logout("additional unneeded tick, not processed\n");
266
/* Save status of EEPROM. */
271
eeprom->address = address;
272
eeprom->command = command;
275
uint16_t eeprom93xx_read(eeprom_t *eeprom)
277
/* Return status of pin DO (0 or 1). */
278
logout("CS=%u DO=%u\n", eeprom->eecs, eeprom->eedo);
279
return (eeprom->eedo);
283
void eeprom93xx_reset(eeprom_t *eeprom)
286
logout("eeprom = 0x%p\n", eeprom);
292
eeprom_t *eeprom93xx_new(DeviceState *dev, uint16_t nwords)
294
/* Add a new EEPROM (with 16, 64 or 256 words). */
308
assert(!"Unsupported EEPROM size, fallback to 64 words!");
313
eeprom = (eeprom_t *)qemu_mallocz(sizeof(*eeprom) + nwords * 2);
314
eeprom->size = nwords;
315
eeprom->addrbits = addrbits;
316
/* Output DO is tristate, read results in 1. */
318
logout("eeprom = 0x%p, nwords = %u\n", eeprom, nwords);
319
vmstate_register(dev, 0, &vmstate_eeprom, eeprom);
323
void eeprom93xx_free(DeviceState *dev, eeprom_t *eeprom)
325
/* Destroy EEPROM. */
326
logout("eeprom = 0x%p\n", eeprom);
327
vmstate_unregister(dev, &vmstate_eeprom, eeprom);
331
uint16_t *eeprom93xx_data(eeprom_t *eeprom)
333
/* Get EEPROM data array. */
334
return &eeprom->contents[0];
added
removed
hw/eeprom93xx.c
