diff options
Diffstat (limited to 'hw/nvram/eeprom_at24c.c')
| -rw-r--r-- | hw/nvram/eeprom_at24c.c | 207 |
1 files changed, 207 insertions, 0 deletions
diff --git a/hw/nvram/eeprom_at24c.c b/hw/nvram/eeprom_at24c.c new file mode 100644 index 000000000..af6f5dbb9 --- /dev/null +++ b/hw/nvram/eeprom_at24c.c @@ -0,0 +1,207 @@ +/* + * *AT24C* series I2C EEPROM + * + * Copyright (c) 2015 Michael Davidsaver + * + * This work is licensed under the terms of the GNU GPL, version 2. See + * the LICENSE file in the top-level directory. + */ + +#include "qemu/osdep.h" + +#include "qapi/error.h" +#include "qemu/module.h" +#include "hw/i2c/i2c.h" +#include "hw/qdev-properties.h" +#include "hw/qdev-properties-system.h" +#include "sysemu/block-backend.h" +#include "qom/object.h" + +/* #define DEBUG_AT24C */ + +#ifdef DEBUG_AT24C +#define DPRINTK(FMT, ...) printf(TYPE_AT24C_EE " : " FMT, ## __VA_ARGS__) +#else +#define DPRINTK(FMT, ...) do {} while (0) +#endif + +#define ERR(FMT, ...) fprintf(stderr, TYPE_AT24C_EE " : " FMT, \ + ## __VA_ARGS__) + +#define TYPE_AT24C_EE "at24c-eeprom" +typedef struct EEPROMState EEPROMState; +DECLARE_INSTANCE_CHECKER(EEPROMState, AT24C_EE, + TYPE_AT24C_EE) + +struct EEPROMState { + I2CSlave parent_obj; + + /* address counter */ + uint16_t cur; + /* total size in bytes */ + uint32_t rsize; + bool writable; + /* cells changed since last START? */ + bool changed; + /* during WRITE, # of address bytes transfered */ + uint8_t haveaddr; + + uint8_t *mem; + + BlockBackend *blk; +}; + +static +int at24c_eeprom_event(I2CSlave *s, enum i2c_event event) +{ + EEPROMState *ee = container_of(s, EEPROMState, parent_obj); + + switch (event) { + case I2C_START_SEND: + case I2C_START_RECV: + case I2C_FINISH: + ee->haveaddr = 0; + DPRINTK("clear\n"); + if (ee->blk && ee->changed) { + int len = blk_pwrite(ee->blk, 0, ee->mem, ee->rsize, 0); + if (len != ee->rsize) { + ERR(TYPE_AT24C_EE + " : failed to write backing file\n"); + } + DPRINTK("Wrote to backing file\n"); + } + ee->changed = false; + break; + case I2C_NACK: + break; + } + return 0; +} + +static +uint8_t at24c_eeprom_recv(I2CSlave *s) +{ + EEPROMState *ee = AT24C_EE(s); + uint8_t ret; + + ret = ee->mem[ee->cur]; + + ee->cur = (ee->cur + 1u) % ee->rsize; + DPRINTK("Recv %02x %c\n", ret, ret); + + return ret; +} + +static +int at24c_eeprom_send(I2CSlave *s, uint8_t data) +{ + EEPROMState *ee = AT24C_EE(s); + + if (ee->haveaddr < 2) { + ee->cur <<= 8; + ee->cur |= data; + ee->haveaddr++; + if (ee->haveaddr == 2) { + ee->cur %= ee->rsize; + DPRINTK("Set pointer %04x\n", ee->cur); + } + + } else { + if (ee->writable) { + DPRINTK("Send %02x\n", data); + ee->mem[ee->cur] = data; + ee->changed = true; + } else { + DPRINTK("Send error %02x read-only\n", data); + } + ee->cur = (ee->cur + 1u) % ee->rsize; + + } + + return 0; +} + +static void at24c_eeprom_realize(DeviceState *dev, Error **errp) +{ + EEPROMState *ee = AT24C_EE(dev); + + if (ee->blk) { + int64_t len = blk_getlength(ee->blk); + + if (len != ee->rsize) { + error_setg(errp, "%s: Backing file size %" PRId64 " != %u", + TYPE_AT24C_EE, len, ee->rsize); + return; + } + + if (blk_set_perm(ee->blk, BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE, + BLK_PERM_ALL, &error_fatal) < 0) + { + error_setg(errp, "%s: Backing file incorrect permission", + TYPE_AT24C_EE); + return; + } + } + + ee->mem = g_malloc0(ee->rsize); +} + +static +void at24c_eeprom_reset(DeviceState *state) +{ + EEPROMState *ee = AT24C_EE(state); + + ee->changed = false; + ee->cur = 0; + ee->haveaddr = 0; + + memset(ee->mem, 0, ee->rsize); + + if (ee->blk) { + int len = blk_pread(ee->blk, 0, ee->mem, ee->rsize); + + if (len != ee->rsize) { + ERR(TYPE_AT24C_EE + " : Failed initial sync with backing file\n"); + } + DPRINTK("Reset read backing file\n"); + } +} + +static Property at24c_eeprom_props[] = { + DEFINE_PROP_UINT32("rom-size", EEPROMState, rsize, 0), + DEFINE_PROP_BOOL("writable", EEPROMState, writable, true), + DEFINE_PROP_DRIVE("drive", EEPROMState, blk), + DEFINE_PROP_END_OF_LIST() +}; + +static +void at24c_eeprom_class_init(ObjectClass *klass, void *data) +{ + DeviceClass *dc = DEVICE_CLASS(klass); + I2CSlaveClass *k = I2C_SLAVE_CLASS(klass); + + dc->realize = &at24c_eeprom_realize; + k->event = &at24c_eeprom_event; + k->recv = &at24c_eeprom_recv; + k->send = &at24c_eeprom_send; + + device_class_set_props(dc, at24c_eeprom_props); + dc->reset = at24c_eeprom_reset; +} + +static +const TypeInfo at24c_eeprom_type = { + .name = TYPE_AT24C_EE, + .parent = TYPE_I2C_SLAVE, + .instance_size = sizeof(EEPROMState), + .class_size = sizeof(I2CSlaveClass), + .class_init = at24c_eeprom_class_init, +}; + +static void at24c_eeprom_register(void) +{ + type_register_static(&at24c_eeprom_type); +} + +type_init(at24c_eeprom_register) |