Merge remote-tracking branch 'remotes/kraxel/tags/seabios-20220118-pull-request'...
[qemu.git] / hw / nvram / eeprom_at24c.c
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/module.h"
14 #include "hw/i2c/i2c.h"
15 #include "hw/qdev-properties.h"
16 #include "hw/qdev-properties-system.h"
17 #include "sysemu/block-backend.h"
18 #include "qom/object.h"
19
20 /* #define DEBUG_AT24C */
21
22 #ifdef DEBUG_AT24C
23 #define DPRINTK(FMT, ...) printf(TYPE_AT24C_EE " : " FMT, ## __VA_ARGS__)
24 #else
25 #define DPRINTK(FMT, ...) do {} while (0)
26 #endif
27
28 #define ERR(FMT, ...) fprintf(stderr, TYPE_AT24C_EE " : " FMT, \
29 ## __VA_ARGS__)
30
31 #define TYPE_AT24C_EE "at24c-eeprom"
32 typedef struct EEPROMState EEPROMState;
33 DECLARE_INSTANCE_CHECKER(EEPROMState, AT24C_EE,
34 TYPE_AT24C_EE)
35
36 struct EEPROMState {
37 I2CSlave parent_obj;
38
39 /* address counter */
40 uint16_t cur;
41 /* total size in bytes */
42 uint32_t rsize;
43 bool writable;
44 /* cells changed since last START? */
45 bool changed;
46 /* during WRITE, # of address bytes transfered */
47 uint8_t haveaddr;
48
49 uint8_t *mem;
50
51 BlockBackend *blk;
52 };
53
54 static
55 int at24c_eeprom_event(I2CSlave *s, enum i2c_event event)
56 {
57 EEPROMState *ee = container_of(s, EEPROMState, parent_obj);
58
59 switch (event) {
60 case I2C_START_SEND:
61 case I2C_START_RECV:
62 case I2C_FINISH:
63 ee->haveaddr = 0;
64 DPRINTK("clear\n");
65 if (ee->blk && ee->changed) {
66 int len = blk_pwrite(ee->blk, 0, ee->mem, ee->rsize, 0);
67 if (len != ee->rsize) {
68 ERR(TYPE_AT24C_EE
69 " : failed to write backing file\n");
70 }
71 DPRINTK("Wrote to backing file\n");
72 }
73 ee->changed = false;
74 break;
75 case I2C_NACK:
76 break;
77 }
78 return 0;
79 }
80
81 static
82 uint8_t at24c_eeprom_recv(I2CSlave *s)
83 {
84 EEPROMState *ee = AT24C_EE(s);
85 uint8_t ret;
86
87 ret = ee->mem[ee->cur];
88
89 ee->cur = (ee->cur + 1u) % ee->rsize;
90 DPRINTK("Recv %02x %c\n", ret, ret);
91
92 return ret;
93 }
94
95 static
96 int at24c_eeprom_send(I2CSlave *s, uint8_t data)
97 {
98 EEPROMState *ee = AT24C_EE(s);
99
100 if (ee->haveaddr < 2) {
101 ee->cur <<= 8;
102 ee->cur |= data;
103 ee->haveaddr++;
104 if (ee->haveaddr == 2) {
105 ee->cur %= ee->rsize;
106 DPRINTK("Set pointer %04x\n", ee->cur);
107 }
108
109 } else {
110 if (ee->writable) {
111 DPRINTK("Send %02x\n", data);
112 ee->mem[ee->cur] = data;
113 ee->changed = true;
114 } else {
115 DPRINTK("Send error %02x read-only\n", data);
116 }
117 ee->cur = (ee->cur + 1u) % ee->rsize;
118
119 }
120
121 return 0;
122 }
123
124 static void at24c_eeprom_realize(DeviceState *dev, Error **errp)
125 {
126 EEPROMState *ee = AT24C_EE(dev);
127
128 if (ee->blk) {
129 int64_t len = blk_getlength(ee->blk);
130
131 if (len != ee->rsize) {
132 error_setg(errp, "%s: Backing file size %" PRId64 " != %u",
133 TYPE_AT24C_EE, len, ee->rsize);
134 return;
135 }
136
137 if (blk_set_perm(ee->blk, BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE,
138 BLK_PERM_ALL, &error_fatal) < 0)
139 {
140 error_setg(errp, "%s: Backing file incorrect permission",
141 TYPE_AT24C_EE);
142 return;
143 }
144 }
145
146 ee->mem = g_malloc0(ee->rsize);
147 }
148
149 static
150 void at24c_eeprom_reset(DeviceState *state)
151 {
152 EEPROMState *ee = AT24C_EE(state);
153
154 ee->changed = false;
155 ee->cur = 0;
156 ee->haveaddr = 0;
157
158 memset(ee->mem, 0, ee->rsize);
159
160 if (ee->blk) {
161 int len = blk_pread(ee->blk, 0, ee->mem, ee->rsize);
162
163 if (len != ee->rsize) {
164 ERR(TYPE_AT24C_EE
165 " : Failed initial sync with backing file\n");
166 }
167 DPRINTK("Reset read backing file\n");
168 }
169 }
170
171 static Property at24c_eeprom_props[] = {
172 DEFINE_PROP_UINT32("rom-size", EEPROMState, rsize, 0),
173 DEFINE_PROP_BOOL("writable", EEPROMState, writable, true),
174 DEFINE_PROP_DRIVE("drive", EEPROMState, blk),
175 DEFINE_PROP_END_OF_LIST()
176 };
177
178 static
179 void at24c_eeprom_class_init(ObjectClass *klass, void *data)
180 {
181 DeviceClass *dc = DEVICE_CLASS(klass);
182 I2CSlaveClass *k = I2C_SLAVE_CLASS(klass);
183
184 dc->realize = &at24c_eeprom_realize;
185 k->event = &at24c_eeprom_event;
186 k->recv = &at24c_eeprom_recv;
187 k->send = &at24c_eeprom_send;
188
189 device_class_set_props(dc, at24c_eeprom_props);
190 dc->reset = at24c_eeprom_reset;
191 }
192
193 static
194 const TypeInfo at24c_eeprom_type = {
195 .name = TYPE_AT24C_EE,
196 .parent = TYPE_I2C_SLAVE,
197 .instance_size = sizeof(EEPROMState),
198 .class_size = sizeof(I2CSlaveClass),
199 .class_init = at24c_eeprom_class_init,
200 };
201
202 static void at24c_eeprom_register(void)
203 {
204 type_register_static(&at24c_eeprom_type);
205 }
206
207 type_init(at24c_eeprom_register)