root / hw / eeprom93xx.c @ 50b7963e
History | View | Annotate | Download (10.5 kB)
1 |
/*
|
---|---|
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
|
17 |
* along with this program; if not, see <http://www.gnu.org/licenses/>.
|
18 |
*/
|
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 |
|
38 |
#include "hw.h" |
39 |
#include "eeprom93xx.h" |
40 |
|
41 |
/* Debug EEPROM emulation. */
|
42 |
//~ #define DEBUG_EEPROM
|
43 |
|
44 |
#ifdef DEBUG_EEPROM
|
45 |
#define logout(fmt, ...) fprintf(stderr, "EEPROM\t%-24s" fmt, __func__, ## __VA_ARGS__) |
46 |
#else
|
47 |
#define logout(fmt, ...) ((void)0) |
48 |
#endif
|
49 |
|
50 |
#define EEPROM_INSTANCE 0 |
51 |
#define OLD_EEPROM_VERSION 20061112 |
52 |
#define EEPROM_VERSION (OLD_EEPROM_VERSION + 1) |
53 |
|
54 |
#if 0
|
55 |
typedef enum {
|
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 */
|
63 |
eeprom_amask = 0x0f,
|
64 |
eeprom_imask = 0xf0
|
65 |
} eeprom_instruction_t;
|
66 |
#endif
|
67 |
|
68 |
#ifdef DEBUG_EEPROM
|
69 |
static const char *opstring[] = { |
70 |
"extended", "write", "read", "erase" |
71 |
}; |
72 |
#endif
|
73 |
|
74 |
struct _eeprom_t {
|
75 |
uint8_t tick; |
76 |
uint8_t address; |
77 |
uint8_t command; |
78 |
uint8_t writable; |
79 |
|
80 |
uint8_t eecs; |
81 |
uint8_t eesk; |
82 |
uint8_t eedo; |
83 |
|
84 |
uint8_t addrbits; |
85 |
uint16_t size; |
86 |
uint16_t data; |
87 |
uint16_t contents[0];
|
88 |
}; |
89 |
|
90 |
/* Code for saving and restoring of EEPROM state. */
|
91 |
|
92 |
/* Restore an uint16_t from an uint8_t
|
93 |
This is a Big hack, but it is how the old state did it.
|
94 |
*/
|
95 |
|
96 |
static int get_uint16_from_uint8(QEMUFile *f, void *pv, size_t size) |
97 |
{ |
98 |
uint16_t *v = pv; |
99 |
*v = qemu_get_ubyte(f); |
100 |
return 0; |
101 |
} |
102 |
|
103 |
static void put_unused(QEMUFile *f, void *pv, size_t size) |
104 |
{ |
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");
|
107 |
exit(0);
|
108 |
} |
109 |
|
110 |
static const VMStateInfo vmstate_hack_uint16_from_uint8 = { |
111 |
.name = "uint16_from_uint8",
|
112 |
.get = get_uint16_from_uint8, |
113 |
.put = put_unused, |
114 |
}; |
115 |
|
116 |
#define VMSTATE_UINT16_HACK_TEST(_f, _s, _t) \
|
117 |
VMSTATE_SINGLE_TEST(_f, _s, _t, 0, vmstate_hack_uint16_from_uint8, uint16_t)
|
118 |
|
119 |
static bool is_old_eeprom_version(void *opaque, int version_id) |
120 |
{ |
121 |
return version_id == OLD_EEPROM_VERSION;
|
122 |
} |
123 |
|
124 |
static const VMStateDescription vmstate_eeprom = { |
125 |
.name = "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), |
134 |
|
135 |
VMSTATE_UINT8(eecs, eeprom_t), |
136 |
VMSTATE_UINT8(eesk, eeprom_t), |
137 |
VMSTATE_UINT8(eedo, eeprom_t), |
138 |
|
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() |
147 |
} |
148 |
}; |
149 |
|
150 |
void eeprom93xx_write(eeprom_t *eeprom, int eecs, int eesk, int eedi) |
151 |
{ |
152 |
uint8_t tick = eeprom->tick; |
153 |
uint8_t eedo = eeprom->eedo; |
154 |
uint16_t address = eeprom->address; |
155 |
uint8_t command = eeprom->command; |
156 |
|
157 |
logout("CS=%u SK=%u DI=%u DO=%u, tick = %u\n",
|
158 |
eecs, eesk, eedi, eedo, tick); |
159 |
|
160 |
if (! eeprom->eecs && eecs) {
|
161 |
/* Start chip select cycle. */
|
162 |
logout("Cycle start, waiting for 1st start bit (0)\n");
|
163 |
tick = 0;
|
164 |
command = 0x0;
|
165 |
address = 0x0;
|
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) { |
171 |
/* Erase all. */
|
172 |
for (address = 0; address < eeprom->size; address++) { |
173 |
eeprom->contents[address] = 0xffff;
|
174 |
} |
175 |
} else if (command == 3) { |
176 |
/* Erase word. */
|
177 |
eeprom->contents[address] = 0xffff;
|
178 |
} else if (tick >= 2 + 2 + eeprom->addrbits + 16) { |
179 |
if (command == 1) { |
180 |
/* Write word. */
|
181 |
eeprom->contents[address] &= eeprom->data; |
182 |
} else if (command == 0 && subcommand == 1) { |
183 |
/* Write all. */
|
184 |
for (address = 0; address < eeprom->size; address++) { |
185 |
eeprom->contents[address] &= eeprom->data; |
186 |
} |
187 |
} |
188 |
} |
189 |
} |
190 |
/* Output DO is tristate, read results in 1. */
|
191 |
eedo = 1;
|
192 |
} else if (eecs && ! eeprom->eesk && eesk) { |
193 |
/* Raising edge of clock shifts data in. */
|
194 |
if (tick == 0) { |
195 |
/* Wait for 1st start bit. */
|
196 |
if (eedi == 0) { |
197 |
logout("Got correct 1st start bit, waiting for 2nd start bit (1)\n");
|
198 |
tick++; |
199 |
} else {
|
200 |
logout("wrong 1st start bit (is 1, should be 0)\n");
|
201 |
tick = 2;
|
202 |
//~ assert(!"wrong start bit");
|
203 |
} |
204 |
} else if (tick == 1) { |
205 |
/* Wait for 2nd start bit. */
|
206 |
if (eedi != 0) { |
207 |
logout("Got correct 2nd start bit, getting command + address\n");
|
208 |
tick++; |
209 |
} else {
|
210 |
logout("1st start bit is longer than needed\n");
|
211 |
} |
212 |
} else if (tick < 2 + 2) { |
213 |
/* Got 2 start bits, transfer 2 opcode bits. */
|
214 |
tick++; |
215 |
command <<= 1;
|
216 |
if (eedi) {
|
217 |
command += 1;
|
218 |
} |
219 |
} else if (tick < 2 + 2 + eeprom->addrbits) { |
220 |
/* Got 2 start bits and 2 opcode bits, transfer all address bits. */
|
221 |
tick++; |
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]); |
226 |
if (command == 2) { |
227 |
eedo = 0;
|
228 |
} |
229 |
address = address % eeprom->size; |
230 |
if (command == 0) { |
231 |
/* Command code in upper 2 bits of address. */
|
232 |
switch (address >> (eeprom->addrbits - 2)) { |
233 |
case 0: |
234 |
logout("write disable command\n");
|
235 |
eeprom->writable = 0;
|
236 |
break;
|
237 |
case 1: |
238 |
logout("write all command\n");
|
239 |
break;
|
240 |
case 2: |
241 |
logout("erase all command\n");
|
242 |
break;
|
243 |
case 3: |
244 |
logout("write enable command\n");
|
245 |
eeprom->writable = 1;
|
246 |
break;
|
247 |
} |
248 |
} else {
|
249 |
/* Read, write or erase word. */
|
250 |
eeprom->data = eeprom->contents[address]; |
251 |
} |
252 |
} |
253 |
} else if (tick < 2 + 2 + eeprom->addrbits + 16) { |
254 |
/* Transfer 16 data bits. */
|
255 |
tick++; |
256 |
if (command == 2) { |
257 |
/* Read word. */
|
258 |
eedo = ((eeprom->data & 0x8000) != 0); |
259 |
} |
260 |
eeprom->data <<= 1;
|
261 |
eeprom->data += eedi; |
262 |
} else {
|
263 |
logout("additional unneeded tick, not processed\n");
|
264 |
} |
265 |
} |
266 |
/* Save status of EEPROM. */
|
267 |
eeprom->tick = tick; |
268 |
eeprom->eecs = eecs; |
269 |
eeprom->eesk = eesk; |
270 |
eeprom->eedo = eedo; |
271 |
eeprom->address = address; |
272 |
eeprom->command = command; |
273 |
} |
274 |
|
275 |
uint16_t eeprom93xx_read(eeprom_t *eeprom) |
276 |
{ |
277 |
/* Return status of pin DO (0 or 1). */
|
278 |
logout("CS=%u DO=%u\n", eeprom->eecs, eeprom->eedo);
|
279 |
return (eeprom->eedo);
|
280 |
} |
281 |
|
282 |
#if 0
|
283 |
void eeprom93xx_reset(eeprom_t *eeprom)
|
284 |
{
|
285 |
/* prepare eeprom */
|
286 |
logout("eeprom = 0x%p\n", eeprom);
|
287 |
eeprom->tick = 0;
|
288 |
eeprom->command = 0;
|
289 |
}
|
290 |
#endif
|
291 |
|
292 |
eeprom_t *eeprom93xx_new(DeviceState *dev, uint16_t nwords) |
293 |
{ |
294 |
/* Add a new EEPROM (with 16, 64 or 256 words). */
|
295 |
eeprom_t *eeprom; |
296 |
uint8_t addrbits; |
297 |
|
298 |
switch (nwords) {
|
299 |
case 16: |
300 |
case 64: |
301 |
addrbits = 6;
|
302 |
break;
|
303 |
case 128: |
304 |
case 256: |
305 |
addrbits = 8;
|
306 |
break;
|
307 |
default:
|
308 |
assert(!"Unsupported EEPROM size, fallback to 64 words!");
|
309 |
nwords = 64;
|
310 |
addrbits = 6;
|
311 |
} |
312 |
|
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. */
|
317 |
eeprom->eedo = 1;
|
318 |
logout("eeprom = 0x%p, nwords = %u\n", eeprom, nwords);
|
319 |
vmstate_register(dev, 0, &vmstate_eeprom, eeprom);
|
320 |
return eeprom;
|
321 |
} |
322 |
|
323 |
void eeprom93xx_free(DeviceState *dev, eeprom_t *eeprom)
|
324 |
{ |
325 |
/* Destroy EEPROM. */
|
326 |
logout("eeprom = 0x%p\n", eeprom);
|
327 |
vmstate_unregister(dev, &vmstate_eeprom, eeprom); |
328 |
qemu_free(eeprom); |
329 |
} |
330 |
|
331 |
uint16_t *eeprom93xx_data(eeprom_t *eeprom) |
332 |
{ |
333 |
/* Get EEPROM data array. */
|
334 |
return &eeprom->contents[0]; |
335 |
} |
336 |
|
337 |
/* eof */
|