[PATCH v3 3/5] hw/nvram/eeprom_at24c: Add init_rom field and at24c_eeprom_init_rom helper

[Peter Delevoryas <peter@pjd.dev>]

Allows users to specify binary data to initialize an EEPROM, allowing users to
emulate data programmed at manufacturing time.

- Added init_rom and init_rom_size attributes to TYPE_AT24C_EE
- Added at24c_eeprom_init_rom helper function to initialize attributes
- If -drive property is provided, it overrides init_rom data

Signed-off-by: Peter Delevoryas <peter@pjd.dev>
---
 hw/nvram/eeprom_at24c.c         | 37 ++++++++++++++++++++++++++++-----
 include/hw/nvram/eeprom_at24c.h |  2 ++
 2 files changed, 34 insertions(+), 5 deletions(-)

diff --git a/hw/nvram/eeprom_at24c.c b/hw/nvram/eeprom_at24c.c
index 98857e3626b9..f8d751fa278d 100644
--- a/hw/nvram/eeprom_at24c.c
+++ b/hw/nvram/eeprom_at24c.c
@@ -50,6 +50,9 @@ struct EEPROMState {
     uint8_t *mem;
 
     BlockBackend *blk;
+
+    const uint8_t *init_rom;
+    uint32_t init_rom_size;
 };
 
 static
@@ -131,19 +134,38 @@ int at24c_eeprom_send(I2CSlave *s, uint8_t data)
 
 I2CSlave *at24c_eeprom_init(I2CBus *bus, uint8_t address, uint32_t rom_size)
 {
-    I2CSlave *i2c_dev = i2c_slave_new(TYPE_AT24C_EE, address);
-    DeviceState *dev = DEVICE(i2c_dev);
+    return at24c_eeprom_init_rom(bus, address, rom_size, NULL, 0);
+}
+
+I2CSlave *at24c_eeprom_init_rom(I2CBus *bus, uint8_t address, uint32_t rom_size,
+                                const uint8_t *init_rom, uint32_t init_rom_size)
+{
+    EEPROMState *s;
+
+    s = AT24C_EE(qdev_new(TYPE_AT24C_EE));
+
+    qdev_prop_set_uint8(DEVICE(s), "address", address);
+    qdev_prop_set_uint32(DEVICE(s), "rom-size", rom_size);
 
-    qdev_prop_set_uint32(dev, "rom-size", rom_size);
-    i2c_slave_realize_and_unref(i2c_dev, bus, &error_abort);
+    /* TODO: Model init_rom with QOM properties. */
+    s->init_rom = init_rom;
+    s->init_rom_size = init_rom_size;
 
-    return i2c_dev;
+    i2c_slave_realize_and_unref(I2C_SLAVE(s), bus, &error_abort);
+
+    return I2C_SLAVE(s);
 }
 
 static void at24c_eeprom_realize(DeviceState *dev, Error **errp)
 {
     EEPROMState *ee = AT24C_EE(dev);
 
+    if (ee->init_rom_size > ee->rsize) {
+        error_setg(errp, "%s: init rom is larger than rom: %u > %u",
+                   TYPE_AT24C_EE, ee->init_rom_size, ee->rsize);
+        return;
+    }
+
     if (ee->blk) {
         int64_t len = blk_getlength(ee->blk);
 
@@ -163,6 +185,7 @@ static void at24c_eeprom_realize(DeviceState *dev, Error **errp)
     }
 
     ee->mem = g_malloc0(ee->rsize);
+
 }
 
 static
@@ -176,6 +199,10 @@ void at24c_eeprom_reset(DeviceState *state)
 
     memset(ee->mem, 0, ee->rsize);
 
+    if (ee->init_rom) {
+        memcpy(ee->mem, ee->init_rom, MIN(ee->init_rom_size, ee->rsize));
+    }
+
     if (ee->blk) {
         int ret = blk_pread(ee->blk, 0, ee->rsize, ee->mem, 0);
 
diff --git a/include/hw/nvram/eeprom_at24c.h b/include/hw/nvram/eeprom_at24c.h
index 196db309d451..5c9149331144 100644
--- a/include/hw/nvram/eeprom_at24c.h
+++ b/include/hw/nvram/eeprom_at24c.h
@@ -19,5 +19,7 @@
  * @bus, and drop the reference to it (the device is realized).
  */
 I2CSlave *at24c_eeprom_init(I2CBus *bus, uint8_t address, uint32_t rom_size);
+I2CSlave *at24c_eeprom_init_rom(I2CBus *bus, uint8_t address, uint32_t rom_size,
+                                const uint8_t *init_rom, uint32_t init_rom_size);
 
 #endif
-- 
2.39.0