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 <string.h> 11 12 #include "qemu/osdep.h" 13 #include "qapi/error.h" 14 #include "hw/hw.h" 15 #include "hw/i2c/i2c.h" 16 #include "sysemu/block-backend.h" 17 18 /* #define DEBUG_AT24C */ 19 20 #ifdef DEBUG_AT24C 21 #define DPRINTK(FMT, ...) printf(TYPE_AT24C_EE " : " FMT, ## __VA_ARGS__) 22 #else 23 #define DPRINTK(FMT, ...) do {} while (0) 24 #endif 25 26 #define ERR(FMT, ...) fprintf(stderr, TYPE_AT24C_EE " : " FMT, \ 27 ## __VA_ARGS__) 28 29 #define TYPE_AT24C_EE "at24c-eeprom" 30 #define AT24C_EE(obj) OBJECT_CHECK(EEPROMState, (obj), TYPE_AT24C_EE) 31 32 typedef struct EEPROMState { 33 I2CSlave parent_obj; 34 35 /* address counter */ 36 uint16_t cur; 37 /* total size in bytes */ 38 uint32_t rsize; 39 bool writable; 40 /* cells changed since last START? */ 41 bool changed; 42 /* during WRITE, # of address bytes transfered */ 43 uint8_t haveaddr; 44 45 uint8_t *mem; 46 47 BlockBackend *blk; 48 } EEPROMState; 49 50 static 51 int at24c_eeprom_event(I2CSlave *s, enum i2c_event event) 52 { 53 EEPROMState *ee = container_of(s, EEPROMState, parent_obj); 54 55 switch (event) { 56 case I2C_START_SEND: 57 case I2C_START_RECV: 58 case I2C_FINISH: 59 ee->haveaddr = 0; 60 DPRINTK("clear\n"); 61 if (ee->blk && ee->changed) { 62 int len = blk_pwrite(ee->blk, 0, ee->mem, ee->rsize, 0); 63 if (len != ee->rsize) { 64 ERR(TYPE_AT24C_EE 65 " : failed to write backing file\n"); 66 } 67 DPRINTK("Wrote to backing file\n"); 68 } 69 ee->changed = false; 70 break; 71 case I2C_NACK: 72 break; 73 } 74 return 0; 75 } 76 77 static 78 int at24c_eeprom_recv(I2CSlave *s) 79 { 80 EEPROMState *ee = AT24C_EE(s); 81 int ret; 82 83 ret = ee->mem[ee->cur]; 84 85 ee->cur = (ee->cur + 1u) % ee->rsize; 86 DPRINTK("Recv %02x %c\n", ret, ret); 87 88 return ret; 89 } 90 91 static 92 int at24c_eeprom_send(I2CSlave *s, uint8_t data) 93 { 94 EEPROMState *ee = AT24C_EE(s); 95 96 if (ee->haveaddr < 2) { 97 ee->cur <<= 8; 98 ee->cur |= data; 99 ee->haveaddr++; 100 if (ee->haveaddr == 2) { 101 ee->cur %= ee->rsize; 102 DPRINTK("Set pointer %04x\n", ee->cur); 103 } 104 105 } else { 106 if (ee->writable) { 107 DPRINTK("Send %02x\n", data); 108 ee->mem[ee->cur] = data; 109 ee->changed = true; 110 } else { 111 DPRINTK("Send error %02x read-only\n", data); 112 } 113 ee->cur = (ee->cur + 1u) % ee->rsize; 114 115 } 116 117 return 0; 118 } 119 120 static 121 int at24c_eeprom_init(I2CSlave *i2c) 122 { 123 EEPROMState *ee = AT24C_EE(i2c); 124 125 ee->mem = g_malloc0(ee->rsize); 126 127 if (ee->blk) { 128 int64_t len = blk_getlength(ee->blk); 129 130 if (len != ee->rsize) { 131 ERR(TYPE_AT24C_EE " : Backing file size %lu != %u\n", 132 (unsigned long)len, (unsigned)ee->rsize); 133 exit(1); 134 } 135 136 if (blk_set_perm(ee->blk, BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE, 137 BLK_PERM_ALL, &error_fatal) < 0) 138 { 139 ERR(TYPE_AT24C_EE 140 " : Backing file incorrect permission\n"); 141 exit(1); 142 } 143 } 144 return 0; 145 } 146 147 static 148 void at24c_eeprom_reset(DeviceState *state) 149 { 150 EEPROMState *ee = AT24C_EE(state); 151 152 ee->changed = false; 153 ee->cur = 0; 154 ee->haveaddr = 0; 155 156 memset(ee->mem, 0, ee->rsize); 157 158 if (ee->blk) { 159 int len = blk_pread(ee->blk, 0, ee->mem, ee->rsize); 160 161 if (len != ee->rsize) { 162 ERR(TYPE_AT24C_EE 163 " : Failed initial sync with backing file\n"); 164 } 165 DPRINTK("Reset read backing file\n"); 166 } 167 } 168 169 static Property at24c_eeprom_props[] = { 170 DEFINE_PROP_UINT32("rom-size", EEPROMState, rsize, 0), 171 DEFINE_PROP_BOOL("writable", EEPROMState, writable, true), 172 DEFINE_PROP_DRIVE("drive", EEPROMState, blk), 173 DEFINE_PROP_END_OF_LIST() 174 }; 175 176 static 177 void at24c_eeprom_class_init(ObjectClass *klass, void *data) 178 { 179 DeviceClass *dc = DEVICE_CLASS(klass); 180 I2CSlaveClass *k = I2C_SLAVE_CLASS(klass); 181 182 k->init = &at24c_eeprom_init; 183 k->event = &at24c_eeprom_event; 184 k->recv = &at24c_eeprom_recv; 185 k->send = &at24c_eeprom_send; 186 187 dc->props = at24c_eeprom_props; 188 dc->reset = at24c_eeprom_reset; 189 } 190 191 static 192 const TypeInfo at24c_eeprom_type = { 193 .name = TYPE_AT24C_EE, 194 .parent = TYPE_I2C_SLAVE, 195 .instance_size = sizeof(EEPROMState), 196 .class_size = sizeof(I2CSlaveClass), 197 .class_init = at24c_eeprom_class_init, 198 }; 199 200 static void at24c_eeprom_register(void) 201 { 202 type_register_static(&at24c_eeprom_type); 203 } 204 205 type_init(at24c_eeprom_register) 206