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     bool writable;
  45     /* cells changed since last START? */
  46     bool changed;
  47     /* during WRITE, # of address bytes transfered */
  48     uint8_t haveaddr;
  49
  50     uint8_t *mem;
  51
  52     BlockBackend *blk;
  53
  54     const uint8_t *init_rom;
  55     uint32_t init_rom_size;
  56 };
  57
  58 static
  59 int at24c_eeprom_event(I2CSlave *s, enum i2c_event event)
  60 {
  61     EEPROMState *ee = AT24C_EE(s);
  62
  63     switch (event) {
  64     case I2C_START_SEND:
  65     case I2C_FINISH:
  66         ee->haveaddr = 0;
  67         /* fallthrough */
  68     case I2C_START_RECV:
  69         DPRINTK("clear\n");
  70         if (ee->blk && ee->changed) {
  71             int ret = blk_pwrite(ee->blk, 0, ee->rsize, ee->mem, 0);
  72             if (ret < 0) {
  73                 ERR(TYPE_AT24C_EE
  74                         " : failed to write backing file\n");
  75             }
  76             DPRINTK("Wrote to backing file\n");
  77         }
  78         ee->changed = false;
  79         break;
  80     case I2C_NACK:
  81         break;
  82     default:
  83         return -1;
  84     }
  85     return 0;
  86 }
  87
  88 static
  89 uint8_t at24c_eeprom_recv(I2CSlave *s)
  90 {
  91     EEPROMState *ee = AT24C_EE(s);
  92     uint8_t ret;
  93
  94     if (ee->haveaddr == 1) {
  95         return 0xff;
  96     }
  97
  98     ret = ee->mem[ee->cur];
  99
 100     ee->cur = (ee->cur + 1u) % ee->rsize;
 101     DPRINTK("Recv %02x %c\n", ret, ret);
 102
 103     return ret;
 104 }
 105
 106 static
 107 int at24c_eeprom_send(I2CSlave *s, uint8_t data)
 108 {
 109     EEPROMState *ee = AT24C_EE(s);
 110
 111     if (ee->haveaddr < 2) {
 112         ee->cur <<= 8;
 113         ee->cur |= data;
 114         ee->haveaddr++;
 115         if (ee->haveaddr == 2) {
 116             ee->cur %= ee->rsize;
 117             DPRINTK("Set pointer %04x\n", ee->cur);
 118         }
 119
 120     } else {
 121         if (ee->writable) {
 122             DPRINTK("Send %02x\n", data);
 123             ee->mem[ee->cur] = data;
 124             ee->changed = true;
 125         } else {
 126             DPRINTK("Send error %02x read-only\n", data);
 127         }
 128         ee->cur = (ee->cur + 1u) % ee->rsize;
 129
 130     }
 131
 132     return 0;
 133 }
 134
 135 I2CSlave *at24c_eeprom_init(I2CBus *bus, uint8_t address, uint32_t rom_size)
 136 {
 137     return at24c_eeprom_init_rom(bus, address, rom_size, NULL, 0);
 138 }
 139
 140 I2CSlave *at24c_eeprom_init_rom(I2CBus *bus, uint8_t address, uint32_t rom_size,
 141                                 const uint8_t *init_rom, uint32_t init_rom_size)
 142 {
 143     EEPROMState *s;
 144
 145     s = AT24C_EE(i2c_slave_new(TYPE_AT24C_EE, address));
 146
 147     qdev_prop_set_uint32(DEVICE(s), "rom-size", rom_size);
 148
 149     /* TODO: Model init_rom with QOM properties. */
 150     s->init_rom = init_rom;
 151     s->init_rom_size = init_rom_size;
 152
 153     i2c_slave_realize_and_unref(I2C_SLAVE(s), bus, &error_abort);
 154
 155     return I2C_SLAVE(s);
 156 }
 157
 158 static void at24c_eeprom_realize(DeviceState *dev, Error **errp)
 159 {
 160     EEPROMState *ee = AT24C_EE(dev);
 161
 162     if (ee->init_rom_size > ee->rsize) {
 163         error_setg(errp, "%s: init rom is larger than rom: %u > %u",
 164                    TYPE_AT24C_EE, ee->init_rom_size, ee->rsize);
 165         return;
 166     }
 167
 168     if (ee->blk) {
 169         int64_t len = blk_getlength(ee->blk);
 170
 171         if (len != ee->rsize) {
 172             error_setg(errp, "%s: Backing file size %" PRId64 " != %u",
 173                        TYPE_AT24C_EE, len, ee->rsize);
 174             return;
 175         }
 176
 177         if (blk_set_perm(ee->blk, BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE,
 178                          BLK_PERM_ALL, &error_fatal) < 0)
 179         {
 180             error_setg(errp, "%s: Backing file incorrect permission",
 181                        TYPE_AT24C_EE);
 182             return;
 183         }
 184     }
 185
 186     ee->mem = g_malloc0(ee->rsize);
 187     memset(ee->mem, 0, ee->rsize);
 188
 189     if (ee->init_rom) {
 190         memcpy(ee->mem, ee->init_rom, MIN(ee->init_rom_size, ee->rsize));
 191     }
 192
 193     if (ee->blk) {
 194         int ret = blk_pread(ee->blk, 0, ee->rsize, ee->mem, 0);
 195
 196         if (ret < 0) {
 197             ERR(TYPE_AT24C_EE
 198                     " : Failed initial sync with backing file\n");
 199         }
 200         DPRINTK("Reset read backing file\n");
 201     }
 202 }
 203
 204 static
 205 void at24c_eeprom_reset(DeviceState *state)
 206 {
 207     EEPROMState *ee = AT24C_EE(state);
 208
 209     ee->changed = false;
 210     ee->cur = 0;
 211     ee->haveaddr = 0;
 212 }
 213
 214 static Property at24c_eeprom_props[] = {
 215     DEFINE_PROP_UINT32("rom-size", EEPROMState, rsize, 0),
 216     DEFINE_PROP_BOOL("writable", EEPROMState, writable, true),
 217     DEFINE_PROP_DRIVE("drive", EEPROMState, blk),
 218     DEFINE_PROP_END_OF_LIST()
 219 };
 220
 221 static
 222 void at24c_eeprom_class_init(ObjectClass *klass, void *data)
 223 {
 224     DeviceClass *dc = DEVICE_CLASS(klass);
 225     I2CSlaveClass *k = I2C_SLAVE_CLASS(klass);
 226
 227     dc->realize = &at24c_eeprom_realize;
 228     k->event = &at24c_eeprom_event;
 229     k->recv = &at24c_eeprom_recv;
 230     k->send = &at24c_eeprom_send;
 231
 232     device_class_set_props(dc, at24c_eeprom_props);
 233     dc->reset = at24c_eeprom_reset;
 234 }
 235
 236 static
 237 const TypeInfo at24c_eeprom_type = {
 238     .name = TYPE_AT24C_EE,
 239     .parent = TYPE_I2C_SLAVE,
 240     .instance_size = sizeof(EEPROMState),
 241     .class_size = sizeof(I2CSlaveClass),
 242     .class_init = at24c_eeprom_class_init,
 243 };
 244
 245 static void at24c_eeprom_register(void)
 246 {
 247     type_register_static(&at24c_eeprom_type);
 248 }
 249
 250 type_init(at24c_eeprom_register)