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/nvram/eeprom_at24c.h"
  16 #include "hw/qdev-properties.h"
  17 #include "hw/qdev-properties-system.h"
  18 #include "sysemu/block-backend.h"
  19 #include "qom/object.h"
  20
  21 /* #define DEBUG_AT24C */
  22
  23 #ifdef DEBUG_AT24C
  24 #define DPRINTK(FMT, ...) printf(TYPE_AT24C_EE " : " FMT, ## __VA_ARGS__)
  25 #else
  26 #define DPRINTK(FMT, ...) do {} while (0)
  27 #endif
  28
  29 #define ERR(FMT, ...) fprintf(stderr, TYPE_AT24C_EE " : " FMT, \
  30                             ## __VA_ARGS__)
  31
  32 #define TYPE_AT24C_EE "at24c-eeprom"
  33 typedef struct EEPROMState EEPROMState;
  34 DECLARE_INSTANCE_CHECKER(EEPROMState, AT24C_EE,
  35                          TYPE_AT24C_EE)
  36
  37 struct EEPROMState {
  38     I2CSlave parent_obj;
  39
  40     /* address counter */
  41     uint16_t cur;
  42     /* total size in bytes */
  43     uint32_t rsize;
  44     /*
  45      * address byte number
  46      *  for  24c01, 24c02 size <= 256 byte, use only 1 byte
  47      *  otherwise size > 256, use 2 byte
  48      */
  49     uint8_t asize;
  50
  51     bool writable;
  52     /* cells changed since last START? */
  53     bool changed;
  54     /* during WRITE, # of address bytes transfered */
  55     uint8_t haveaddr;
  56
  57     uint8_t *mem;
  58
  59     BlockBackend *blk;
  60
  61     const uint8_t *init_rom;
  62     uint32_t init_rom_size;
  63 };
  64
  65 static
  66 int at24c_eeprom_event(I2CSlave *s, enum i2c_event event)
  67 {
  68     EEPROMState *ee = AT24C_EE(s);
  69
  70     switch (event) {
  71     case I2C_START_SEND:
  72     case I2C_FINISH:
  73         ee->haveaddr = 0;
  74         /* fallthrough */
  75     case I2C_START_RECV:
  76         DPRINTK("clear\n");
  77         if (ee->blk && ee->changed) {
  78             int ret = blk_pwrite(ee->blk, 0, ee->rsize, ee->mem, 0);
  79             if (ret < 0) {
  80                 ERR(TYPE_AT24C_EE
  81                         " : failed to write backing file\n");
  82             }
  83             DPRINTK("Wrote to backing file\n");
  84         }
  85         ee->changed = false;
  86         break;
  87     case I2C_NACK:
  88         break;
  89     default:
  90         return -1;
  91     }
  92     return 0;
  93 }
  94
  95 static
  96 uint8_t at24c_eeprom_recv(I2CSlave *s)
  97 {
  98     EEPROMState *ee = AT24C_EE(s);
  99     uint8_t ret;
 100
 101     /*
 102      * If got the byte address but not completely with address size
 103      * will return the invalid value
 104      */
 105     if (ee->haveaddr > 0 && ee->haveaddr < ee->asize) {
 106         return 0xff;
 107     }
 108
 109     ret = ee->mem[ee->cur];
 110
 111     ee->cur = (ee->cur + 1u) % ee->rsize;
 112     DPRINTK("Recv %02x %c\n", ret, ret);
 113
 114     return ret;
 115 }
 116
 117 static
 118 int at24c_eeprom_send(I2CSlave *s, uint8_t data)
 119 {
 120     EEPROMState *ee = AT24C_EE(s);
 121
 122     if (ee->haveaddr < ee->asize) {
 123         ee->cur <<= 8;
 124         ee->cur |= data;
 125         ee->haveaddr++;
 126         if (ee->haveaddr == ee->asize) {
 127             ee->cur %= ee->rsize;
 128             DPRINTK("Set pointer %04x\n", ee->cur);
 129         }
 130
 131     } else {
 132         if (ee->writable) {
 133             DPRINTK("Send %02x\n", data);
 134             ee->mem[ee->cur] = data;
 135             ee->changed = true;
 136         } else {
 137             DPRINTK("Send error %02x read-only\n", data);
 138         }
 139         ee->cur = (ee->cur + 1u) % ee->rsize;
 140
 141     }
 142
 143     return 0;
 144 }
 145
 146 I2CSlave *at24c_eeprom_init(I2CBus *bus, uint8_t address, uint32_t rom_size)
 147 {
 148     return at24c_eeprom_init_rom(bus, address, rom_size, NULL, 0);
 149 }
 150
 151 I2CSlave *at24c_eeprom_init_rom(I2CBus *bus, uint8_t address, uint32_t rom_size,
 152                                 const uint8_t *init_rom, uint32_t init_rom_size)
 153 {
 154     EEPROMState *s;
 155
 156     s = AT24C_EE(i2c_slave_new(TYPE_AT24C_EE, address));
 157
 158     qdev_prop_set_uint32(DEVICE(s), "rom-size", rom_size);
 159
 160     /* TODO: Model init_rom with QOM properties. */
 161     s->init_rom = init_rom;
 162     s->init_rom_size = init_rom_size;
 163
 164     i2c_slave_realize_and_unref(I2C_SLAVE(s), bus, &error_abort);
 165
 166     return I2C_SLAVE(s);
 167 }
 168
 169 static void at24c_eeprom_realize(DeviceState *dev, Error **errp)
 170 {
 171     EEPROMState *ee = AT24C_EE(dev);
 172
 173     if (ee->init_rom_size > ee->rsize) {
 174         error_setg(errp, "%s: init rom is larger than rom: %u > %u",
 175                    TYPE_AT24C_EE, ee->init_rom_size, ee->rsize);
 176         return;
 177     }
 178
 179     if (ee->blk) {
 180         int64_t len = blk_getlength(ee->blk);
 181
 182         if (len != ee->rsize) {
 183             error_setg(errp, "%s: Backing file size %" PRId64 " != %u",
 184                        TYPE_AT24C_EE, len, ee->rsize);
 185             return;
 186         }
 187
 188         if (blk_set_perm(ee->blk, BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE,
 189                          BLK_PERM_ALL, &error_fatal) < 0)
 190         {
 191             error_setg(errp, "%s: Backing file incorrect permission",
 192                        TYPE_AT24C_EE);
 193             return;
 194         }
 195     }
 196
 197     ee->mem = g_malloc0(ee->rsize);
 198     memset(ee->mem, 0, ee->rsize);
 199
 200     if (ee->init_rom) {
 201         memcpy(ee->mem, ee->init_rom, MIN(ee->init_rom_size, ee->rsize));
 202     }
 203
 204     if (ee->blk) {
 205         int ret = blk_pread(ee->blk, 0, ee->rsize, ee->mem, 0);
 206
 207         if (ret < 0) {
 208             ERR(TYPE_AT24C_EE
 209                     " : Failed initial sync with backing file\n");
 210         }
 211         DPRINTK("Reset read backing file\n");
 212     }
 213
 214     /*
 215      * If address size didn't define with property set
 216      *   value is 0 as default, setting it by Rom size detecting.
 217      */
 218     if (ee->asize == 0) {
 219         if (ee->rsize <= 256) {
 220             ee->asize = 1;
 221         } else {
 222             ee->asize = 2;
 223         }
 224     }
 225 }
 226
 227 static
 228 void at24c_eeprom_reset(DeviceState *state)
 229 {
 230     EEPROMState *ee = AT24C_EE(state);
 231
 232     ee->changed = false;
 233     ee->cur = 0;
 234     ee->haveaddr = 0;
 235 }
 236
 237 static Property at24c_eeprom_props[] = {
 238     DEFINE_PROP_UINT32("rom-size", EEPROMState, rsize, 0),
 239     DEFINE_PROP_UINT8("address-size", EEPROMState, asize, 0),
 240     DEFINE_PROP_BOOL("writable", EEPROMState, writable, true),
 241     DEFINE_PROP_DRIVE("drive", EEPROMState, blk),
 242     DEFINE_PROP_END_OF_LIST()
 243 };
 244
 245 static
 246 void at24c_eeprom_class_init(ObjectClass *klass, void *data)
 247 {
 248     DeviceClass *dc = DEVICE_CLASS(klass);
 249     I2CSlaveClass *k = I2C_SLAVE_CLASS(klass);
 250
 251     dc->realize = &at24c_eeprom_realize;
 252     k->event = &at24c_eeprom_event;
 253     k->recv = &at24c_eeprom_recv;
 254     k->send = &at24c_eeprom_send;
 255
 256     device_class_set_props(dc, at24c_eeprom_props);
 257     dc->reset = at24c_eeprom_reset;
 258 }
 259
 260 static
 261 const TypeInfo at24c_eeprom_type = {
 262     .name = TYPE_AT24C_EE,
 263     .parent = TYPE_I2C_SLAVE,
 264     .instance_size = sizeof(EEPROMState),
 265     .class_size = sizeof(I2CSlaveClass),
 266     .class_init = at24c_eeprom_class_init,
 267 };
 268
 269 static void at24c_eeprom_register(void)
 270 {
 271     type_register_static(&at24c_eeprom_type);
 272 }
 273
 274 type_init(at24c_eeprom_register)