Re: [PATCH v2 3/5] hw/nvram/eeprom_at24c: Add init_rom field and at24c_eeprom_init_rom helper

[Cédric Le Goater]

On 1/17/23 00:56, Peter Delevoryas wrote:
> 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
>
> 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..bb9ee75864fe 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
> @@ -131,13 +134,26 @@ 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. */

ok. This can be fixed with a property later when we have support.

> +    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)
> @@ -162,7 +178,14 @@ static void at24c_eeprom_realize(DeviceState *dev, Error 
> **errp)
>           }
>       }
>   
> +    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;
> +    }
> +
>       ee->mem = g_malloc0(ee->rsize);
> +
>   }
>   
>   static
> @@ -185,6 +208,10 @@ void at24c_eeprom_reset(DeviceState *state)
>           }
>           DPRINTK("Reset read backing file\n");
>       }
> +
> +    if (ee->init_rom) {
> +        memcpy(ee->mem, ee->init_rom, MIN(ee->init_rom_size, ee->rsize));
> +    }

I don't think we can have both an init_rom and a drive. The realize
handler should report an error in that case.

>   }
>   
>   static Property at24c_eeprom_props[] = {
> diff --git a/include/hw/nvram/eeprom_at24c.h b/include/hw/nvram/eeprom_at24c.h
> index 79a36b53ca87..e490826ab1d0 100644
> --- a/include/hw/nvram/eeprom_at24c.h
> +++ b/include/hw/nvram/eeprom_at24c.h
> @@ -6,5 +6,7 @@
>   #include "hw/i2c/i2c.h"
>   
>   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