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 = AT24C_EE(s); 58 59 switch (event) { 60 case I2C_START_SEND: 61 case I2C_FINISH: 62 ee->haveaddr = 0; 63 /* fallthrough */ 64 case I2C_START_RECV: 65 DPRINTK("clear\n"); 66 if (ee->blk && ee->changed) { 67 int len = blk_pwrite(ee->blk, 0, ee->mem, ee->rsize, 0); 68 if (len != ee->rsize) { 69 ERR(TYPE_AT24C_EE 70 " : failed to write backing file\n"); 71 } 72 DPRINTK("Wrote to backing file\n"); 73 } 74 ee->changed = false; 75 break; 76 case I2C_NACK: 77 break; 78 } 79 return 0; 80 } 81 82 static 83 uint8_t at24c_eeprom_recv(I2CSlave *s) 84 { 85 EEPROMState *ee = AT24C_EE(s); 86 uint8_t ret; 87 88 if (ee->haveaddr == 1) { 89 return 0xff; 90 } 91 92 ret = ee->mem[ee->cur]; 93 94 ee->cur = (ee->cur + 1u) % ee->rsize; 95 DPRINTK("Recv %02x %c\n", ret, ret); 96 97 return ret; 98 } 99 100 static 101 int at24c_eeprom_send(I2CSlave *s, uint8_t data) 102 { 103 EEPROMState *ee = AT24C_EE(s); 104 105 if (ee->haveaddr < 2) { 106 ee->cur <<= 8; 107 ee->cur |= data; 108 ee->haveaddr++; 109 if (ee->haveaddr == 2) { 110 ee->cur %= ee->rsize; 111 DPRINTK("Set pointer %04x\n", ee->cur); 112 } 113 114 } else { 115 if (ee->writable) { 116 DPRINTK("Send %02x\n", data); 117 ee->mem[ee->cur] = data; 118 ee->changed = true; 119 } else { 120 DPRINTK("Send error %02x read-only\n", data); 121 } 122 ee->cur = (ee->cur + 1u) % ee->rsize; 123 124 } 125 126 return 0; 127 } 128 129 static void at24c_eeprom_realize(DeviceState *dev, Error **errp) 130 { 131 EEPROMState *ee = AT24C_EE(dev); 132 133 if (ee->blk) { 134 int64_t len = blk_getlength(ee->blk); 135 136 if (len != ee->rsize) { 137 error_setg(errp, "%s: Backing file size %" PRId64 " != %u", 138 TYPE_AT24C_EE, len, ee->rsize); 139 return; 140 } 141 142 if (blk_set_perm(ee->blk, BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE, 143 BLK_PERM_ALL, &error_fatal) < 0) 144 { 145 error_setg(errp, "%s: Backing file incorrect permission", 146 TYPE_AT24C_EE); 147 return; 148 } 149 } 150 151 ee->mem = g_malloc0(ee->rsize); 152 } 153 154 static 155 void at24c_eeprom_reset(DeviceState *state) 156 { 157 EEPROMState *ee = AT24C_EE(state); 158 159 ee->changed = false; 160 ee->cur = 0; 161 ee->haveaddr = 0; 162 163 memset(ee->mem, 0, ee->rsize); 164 165 if (ee->blk) { 166 int len = blk_pread(ee->blk, 0, ee->mem, ee->rsize); 167 168 if (len != ee->rsize) { 169 ERR(TYPE_AT24C_EE 170 " : Failed initial sync with backing file\n"); 171 } 172 DPRINTK("Reset read backing file\n"); 173 } 174 } 175 176 static Property at24c_eeprom_props[] = { 177 DEFINE_PROP_UINT32("rom-size", EEPROMState, rsize, 0), 178 DEFINE_PROP_BOOL("writable", EEPROMState, writable, true), 179 DEFINE_PROP_DRIVE("drive", EEPROMState, blk), 180 DEFINE_PROP_END_OF_LIST() 181 }; 182 183 static 184 void at24c_eeprom_class_init(ObjectClass *klass, void *data) 185 { 186 DeviceClass *dc = DEVICE_CLASS(klass); 187 I2CSlaveClass *k = I2C_SLAVE_CLASS(klass); 188 189 dc->realize = &at24c_eeprom_realize; 190 k->event = &at24c_eeprom_event; 191 k->recv = &at24c_eeprom_recv; 192 k->send = &at24c_eeprom_send; 193 194 device_class_set_props(dc, at24c_eeprom_props); 195 dc->reset = at24c_eeprom_reset; 196 } 197 198 static 199 const TypeInfo at24c_eeprom_type = { 200 .name = TYPE_AT24C_EE, 201 .parent = TYPE_I2C_SLAVE, 202 .instance_size = sizeof(EEPROMState), 203 .class_size = sizeof(I2CSlaveClass), 204 .class_init = at24c_eeprom_class_init, 205 }; 206 207 static void at24c_eeprom_register(void) 208 { 209 type_register_static(&at24c_eeprom_type); 210 } 211 212 type_init(at24c_eeprom_register) 213