1 /*
2 * *AT24C* series I2C EEPROM
3 *
4 * Copyright (c) 2015 Michael Davidsaver
5 *
6 * This work is licensed under the terms of the GNU GPL, version 2. See
7 * the LICENSE file in the top-level directory.
8 */
9
10 #include "qemu/osdep.h"
11
12 #include "qapi/error.h"
13 #include "qemu/error-report.h"
14 #include "qemu/module.h"
15 #include "hw/i2c/i2c.h"
16 #include "hw/nvram/eeprom_at24c.h"
17 #include "hw/qdev-properties.h"
18 #include "hw/qdev-properties-system.h"
19 #include "system/block-backend.h"
20 #include "qom/object.h"
21
22 /* #define DEBUG_AT24C */
23
24 #ifdef DEBUG_AT24C
25 #define DPRINTK(FMT, ...) printf(TYPE_AT24C_EE " : " FMT, ## __VA_ARGS__)
26 #else
27 #define DPRINTK(FMT, ...) do {} while (0)
28 #endif
29
30 #define TYPE_AT24C_EE "at24c-eeprom"
31 OBJECT_DECLARE_SIMPLE_TYPE(EEPROMState, AT24C_EE)
32
33 struct EEPROMState {
34 I2CSlave parent_obj;
35
36 /* address counter */
37 uint16_t cur;
38 /* total size in bytes */
39 uint32_t rsize;
40 /*
41 * address byte number
42 * for 24c01, 24c02 size <= 256 byte, use only 1 byte
43 * otherwise size > 256, use 2 byte
44 */
45 uint8_t asize;
46
47 bool writable;
48 /* cells changed since last START? */
49 bool changed;
50 /* during WRITE, # of address bytes transferred */
51 uint8_t haveaddr;
52
53 uint8_t *mem;
54
55 BlockBackend *blk;
56
57 const uint8_t *init_rom;
58 uint32_t init_rom_size;
59 };
60
61 static
at24c_eeprom_event(I2CSlave * s,enum i2c_event event)62 int at24c_eeprom_event(I2CSlave *s, enum i2c_event event)
63 {
64 EEPROMState *ee = AT24C_EE(s);
65
66 switch (event) {
67 case I2C_START_SEND:
68 case I2C_FINISH:
69 ee->haveaddr = 0;
70 /* fallthrough */
71 case I2C_START_RECV:
72 DPRINTK("clear\n");
73 if (ee->blk && ee->changed) {
74 int ret = blk_pwrite(ee->blk, 0, ee->rsize, ee->mem, 0);
75 if (ret < 0) {
76 error_report("%s: failed to write backing file", __func__);
77 }
78 DPRINTK("Wrote to backing file\n");
79 }
80 ee->changed = false;
81 break;
82 case I2C_NACK:
83 break;
84 default:
85 return -1;
86 }
87 return 0;
88 }
89
90 static
at24c_eeprom_recv(I2CSlave * s)91 uint8_t at24c_eeprom_recv(I2CSlave *s)
92 {
93 EEPROMState *ee = AT24C_EE(s);
94 uint8_t ret;
95
96 /*
97 * If got the byte address but not completely with address size
98 * will return the invalid value
99 */
100 if (ee->haveaddr > 0 && ee->haveaddr < ee->asize) {
101 return 0xff;
102 }
103
104 ret = ee->mem[ee->cur];
105
106 ee->cur = (ee->cur + 1u) % ee->rsize;
107 DPRINTK("Recv %02x %c\n", ret, ret);
108
109 return ret;
110 }
111
112 static
at24c_eeprom_send(I2CSlave * s,uint8_t data)113 int at24c_eeprom_send(I2CSlave *s, uint8_t data)
114 {
115 EEPROMState *ee = AT24C_EE(s);
116
117 if (ee->haveaddr < ee->asize) {
118 ee->cur <<= 8;
119 ee->cur |= data;
120 ee->haveaddr++;
121 if (ee->haveaddr == ee->asize) {
122 ee->cur %= ee->rsize;
123 DPRINTK("Set pointer %04x\n", ee->cur);
124 }
125
126 } else {
127 if (ee->writable) {
128 DPRINTK("Send %02x\n", data);
129 ee->mem[ee->cur] = data;
130 ee->changed = true;
131 } else {
132 DPRINTK("Send error %02x read-only\n", data);
133 }
134 ee->cur = (ee->cur + 1u) % ee->rsize;
135
136 }
137
138 return 0;
139 }
140
at24c_eeprom_init(I2CBus * bus,uint8_t address,uint32_t rom_size)141 I2CSlave *at24c_eeprom_init(I2CBus *bus, uint8_t address, uint32_t rom_size)
142 {
143 return at24c_eeprom_init_rom(bus, address, rom_size, NULL, 0);
144 }
145
at24c_eeprom_init_rom(I2CBus * bus,uint8_t address,uint32_t rom_size,const uint8_t * init_rom,uint32_t init_rom_size)146 I2CSlave *at24c_eeprom_init_rom(I2CBus *bus, uint8_t address, uint32_t rom_size,
147 const uint8_t *init_rom, uint32_t init_rom_size)
148 {
149 EEPROMState *s;
150
151 s = AT24C_EE(i2c_slave_new(TYPE_AT24C_EE, address));
152
153 qdev_prop_set_uint32(DEVICE(s), "rom-size", rom_size);
154
155 /* TODO: Model init_rom with QOM properties. */
156 s->init_rom = init_rom;
157 s->init_rom_size = init_rom_size;
158
159 i2c_slave_realize_and_unref(I2C_SLAVE(s), bus, &error_abort);
160
161 return I2C_SLAVE(s);
162 }
163
at24c_eeprom_realize(DeviceState * dev,Error ** errp)164 static void at24c_eeprom_realize(DeviceState *dev, Error **errp)
165 {
166 EEPROMState *ee = AT24C_EE(dev);
167
168 if (ee->init_rom_size > ee->rsize) {
169 error_setg(errp, "%s: init rom is larger than rom: %u > %u",
170 TYPE_AT24C_EE, ee->init_rom_size, ee->rsize);
171 return;
172 }
173
174 if (ee->blk) {
175 int64_t len = blk_getlength(ee->blk);
176
177 if (len != ee->rsize) {
178 error_setg(errp, "%s: Backing file size %" PRId64 " != %u",
179 TYPE_AT24C_EE, len, ee->rsize);
180 return;
181 }
182
183 if (blk_set_perm(ee->blk, BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE,
184 BLK_PERM_ALL, &error_fatal) < 0)
185 {
186 error_setg(errp, "%s: Backing file incorrect permission",
187 TYPE_AT24C_EE);
188 return;
189 }
190 }
191
192 ee->mem = g_malloc0(ee->rsize);
193
194 if (ee->blk) {
195 int ret = blk_pread(ee->blk, 0, ee->rsize, ee->mem, 0);
196
197 if (ret < 0) {
198 error_setg(errp, "%s: Failed initial sync with backing file",
199 TYPE_AT24C_EE);
200 return;
201 }
202 DPRINTK("Reset read backing file\n");
203 } else if (ee->init_rom) {
204 memcpy(ee->mem, ee->init_rom, MIN(ee->init_rom_size, ee->rsize));
205 }
206
207 /*
208 * If address size didn't define with property set
209 * value is 0 as default, setting it by Rom size detecting.
210 */
211 if (ee->asize == 0) {
212 if (ee->rsize <= 256) {
213 ee->asize = 1;
214 } else {
215 ee->asize = 2;
216 }
217 }
218 }
219
220 static
at24c_eeprom_reset(DeviceState * state)221 void at24c_eeprom_reset(DeviceState *state)
222 {
223 EEPROMState *ee = AT24C_EE(state);
224
225 ee->changed = false;
226 ee->cur = 0;
227 ee->haveaddr = 0;
228 }
229
230 static const Property at24c_eeprom_props[] = {
231 DEFINE_PROP_UINT32("rom-size", EEPROMState, rsize, 0),
232 DEFINE_PROP_UINT8("address-size", EEPROMState, asize, 0),
233 DEFINE_PROP_BOOL("writable", EEPROMState, writable, true),
234 DEFINE_PROP_DRIVE("drive", EEPROMState, blk),
235 };
236
237 static
at24c_eeprom_class_init(ObjectClass * klass,const void * data)238 void at24c_eeprom_class_init(ObjectClass *klass, const void *data)
239 {
240 DeviceClass *dc = DEVICE_CLASS(klass);
241 I2CSlaveClass *k = I2C_SLAVE_CLASS(klass);
242
243 dc->realize = &at24c_eeprom_realize;
244 k->event = &at24c_eeprom_event;
245 k->recv = &at24c_eeprom_recv;
246 k->send = &at24c_eeprom_send;
247
248 device_class_set_props(dc, at24c_eeprom_props);
249 device_class_set_legacy_reset(dc, at24c_eeprom_reset);
250 }
251
252 static
253 const TypeInfo at24c_eeprom_type = {
254 .name = TYPE_AT24C_EE,
255 .parent = TYPE_I2C_SLAVE,
256 .instance_size = sizeof(EEPROMState),
257 .class_size = sizeof(I2CSlaveClass),
258 .class_init = at24c_eeprom_class_init,
259 };
260
at24c_eeprom_register(void)261 static void at24c_eeprom_register(void)
262 {
263 type_register_static(&at24c_eeprom_type);
264 }
265
266 type_init(at24c_eeprom_register)
267