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_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) 208