Re: [Qemu-devel] [PATCH v3 11/16] i2c:smbus_slave: Add an SMBus vmstate structure

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* minyard@acm.org (minyard@acm.org) wrote:
> From: Corey Minyard <cminyard@mvista.com>
> 
> There is no vmstate handling for SMBus, so no device sitting on SMBus
> can have a state transfer that works reliably.  So add it.
> 
> Signed-off-by: Corey Minyard <cminyard@mvista.com>

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Michael S. Tsirkin <mst@redhat.com>
> Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
> ---
>  hw/i2c/smbus_slave.c         | 18 ++++++++++++++++++
>  include/hw/i2c/smbus_slave.h | 24 +++++++++++++++++++++---
>  2 files changed, 39 insertions(+), 3 deletions(-)
> 
> diff --git a/hw/i2c/smbus_slave.c b/hw/i2c/smbus_slave.c
> index d03f714608..e839c1dd11 100644
> --- a/hw/i2c/smbus_slave.c
> +++ b/hw/i2c/smbus_slave.c
> @@ -206,6 +206,24 @@ static void smbus_device_class_init(ObjectClass *klass, void *data)
>      sc->send = smbus_i2c_send;
>  }
>  
> +bool smbus_vmstate_needed(SMBusDevice *dev)
> +{
> +    return dev->mode != SMBUS_IDLE;
> +}
> +
> +const VMStateDescription vmstate_smbus_device = {
> +    .name = TYPE_SMBUS_DEVICE,
> +    .version_id = 1,
> +    .minimum_version_id = 1,
> +    .fields      = (VMStateField[]) {
> +        VMSTATE_I2C_SLAVE(i2c, SMBusDevice),
> +        VMSTATE_INT32(mode, SMBusDevice),
> +        VMSTATE_INT32(data_len, SMBusDevice),
> +        VMSTATE_UINT8_ARRAY(data_buf, SMBusDevice, SMBUS_DATA_MAX_LEN),
> +        VMSTATE_END_OF_LIST()
> +    }
> +};
> +
>  static const TypeInfo smbus_device_type_info = {
>      .name = TYPE_SMBUS_DEVICE,
>      .parent = TYPE_I2C_SLAVE,
> diff --git a/include/hw/i2c/smbus_slave.h b/include/hw/i2c/smbus_slave.h
> index fad2db9c76..78fd45cb51 100644
> --- a/include/hw/i2c/smbus_slave.h
> +++ b/include/hw/i2c/smbus_slave.h
> @@ -75,14 +75,32 @@ typedef struct SMBusDeviceClass
>      void (*transaction_complete)(SMBusDevice *dev);
>  } SMBusDeviceClass;
>  
> +#define SMBUS_DATA_MAX_LEN 34  /* command + len + 32 bytes of data.  */
> +
>  struct SMBusDevice {
>      /* The SMBus protocol is implemented on top of I2C.  */
>      I2CSlave i2c;
>  
>      /* Remaining fields for internal use only.  */
> -    int mode;
> -    int data_len;
> -    uint8_t data_buf[34]; /* command + len + 32 bytes of data.  */
> +    int32_t mode;
> +    int32_t data_len;
> +    uint8_t data_buf[SMBUS_DATA_MAX_LEN];
>  };
>  
> +extern const VMStateDescription vmstate_smbus_device;
> +
> +#define VMSTATE_SMBUS_DEVICE(_field, _state) {                       \
> +    .name       = (stringify(_field)),                               \
> +    .size       = sizeof(SMBusDevice),                               \
> +    .vmsd       = &vmstate_smbus_device,                             \
> +    .flags      = VMS_STRUCT,                                        \
> +    .offset     = vmstate_offset_value(_state, _field, SMBusDevice), \
> +}
> +
> +/*
> + * Users should call this in their .needed functions to know if the
> + * SMBus slave data needs to be transferred.
> + */
> +bool smbus_vmstate_needed(SMBusDevice *dev);
> +
>  #endif
> -- 
> 2.17.1
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK