Re: [Qemu-devel] [PATCH qom-next v2 3/5] target-arm: Use parent classes for reset + realize

[Igor Mammedov <imammedo@redhat.com>]

On Thu, 11 Jul 2013 11:47:16 +1000
peter.crosthwaite@xilinx.com wrote:

> From: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
> 
> ARMCPUClass is only needed for parent-class abstract function access.
> Just use parent classes for reset and realize access and remove
> ARMCPUClass completely.
> 
> Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
> ---
> 
>  target-arm/cpu-qom.h | 20 --------------------
>  target-arm/cpu.c     | 16 +++++++---------
>  2 files changed, 7 insertions(+), 29 deletions(-)
> 
> diff --git a/target-arm/cpu-qom.h b/target-arm/cpu-qom.h
> index ef6261f..bdad93a 100644
> --- a/target-arm/cpu-qom.h
> +++ b/target-arm/cpu-qom.h
> @@ -24,28 +24,8 @@
>  
>  #define TYPE_ARM_CPU "arm-cpu"
>  
> -#define ARM_CPU_CLASS(klass) \
> -    OBJECT_CLASS_CHECK(ARMCPUClass, (klass), TYPE_ARM_CPU)
>  #define ARM_CPU(obj) \
>      OBJECT_CHECK(ARMCPU, (obj), TYPE_ARM_CPU)
> -#define ARM_CPU_GET_CLASS(obj) \
> -    OBJECT_GET_CLASS(ARMCPUClass, (obj), TYPE_ARM_CPU)
> -
> -/**
> - * ARMCPUClass:
> - * @parent_realize: The parent class' realize handler.
> - * @parent_reset: The parent class' reset handler.
> - *
> - * An ARM CPU model.
> - */
> -typedef struct ARMCPUClass {
> -    /*< private >*/
> -    CPUClass parent_class;
> -    /*< public >*/
> -
> -    DeviceRealize parent_realize;
> -    void (*parent_reset)(CPUState *cpu);
> -} ARMCPUClass;
>  
>  /**
>   * ARMCPU:
> diff --git a/target-arm/cpu.c b/target-arm/cpu.c
> index ed53df8..ad5ec7b 100644
> --- a/target-arm/cpu.c
> +++ b/target-arm/cpu.c
> @@ -60,7 +60,8 @@ static void cp_reg_reset(gpointer key, gpointer value, gpointer opaque)
>  static void arm_cpu_reset(CPUState *s)
>  {
>      ARMCPU *cpu = ARM_CPU(s);
> -    ARMCPUClass *acc = ARM_CPU_GET_CLASS(cpu);
> +    CPUClass *cc_parent =
> +            CPU_CLASS(object_class_get_parent_by_name(TYPE_ARM_CPU));
Maybe object_class_get_parent_of_type() would be less confusing?

This usage assumes that parent of TYPE_ARM_CPU is TYPE_CPU and if
another TYPE_X added between them, it might break if TYPE_X doesn't
re-implement this logic in its reset.

Could reset be modeled like DEVICE.instance_init() instead? Then
no explicit access to parent from child would be needed and it
still leaves possibility to override resets if parent->child
propagation order is not desirable for a particular device.

>      CPUARMState *env = &cpu->env;
>  
>      if (qemu_loglevel_mask(CPU_LOG_RESET)) {
> @@ -68,7 +69,7 @@ static void arm_cpu_reset(CPUState *s)
>          log_cpu_state(env, 0);
>      }
>  
> -    acc->parent_reset(s);
> +    cc_parent->reset(s);
>  
>      memset(env, 0, offsetof(CPUARMState, breakpoints));
>      g_hash_table_foreach(cpu->cp_regs, cp_reg_reset, cpu);
> @@ -158,7 +159,8 @@ static void arm_cpu_finalizefn(Object *obj)
>  static void arm_cpu_realizefn(DeviceState *dev, Error **errp)
>  {
>      ARMCPU *cpu = ARM_CPU(dev);
> -    ARMCPUClass *acc = ARM_CPU_GET_CLASS(dev);
> +    DeviceClass *dc_parent =
> +            DEVICE_CLASS(object_class_get_parent_by_name(TYPE_ARM_CPU));
>      CPUARMState *env = &cpu->env;
>  
>      /* Some features automatically imply others: */
> @@ -209,7 +211,7 @@ static void arm_cpu_realizefn(DeviceState *dev, Error **errp)
>  
>      cpu_reset(CPU(cpu));
>  
> -    acc->parent_realize(dev, errp);
> +    dc_parent->realize(dev, errp);
>  }
>  
>  /* CPU models */
> @@ -803,14 +805,11 @@ static const ARMCPUInfo arm_cpus[] = {
>  
>  static void arm_cpu_class_init(ObjectClass *oc, void *data)
>  {
> -    ARMCPUClass *acc = ARM_CPU_CLASS(oc);
> -    CPUClass *cc = CPU_CLASS(acc);
> +    CPUClass *cc = CPU_CLASS(oc);
>      DeviceClass *dc = DEVICE_CLASS(oc);
>  
> -    acc->parent_realize = dc->realize;
>      dc->realize = arm_cpu_realizefn;
>  
> -    acc->parent_reset = cc->reset;
>      cc->reset = arm_cpu_reset;
>  
>      cc->class_by_name = arm_cpu_class_by_name;
> @@ -839,7 +838,6 @@ static const TypeInfo arm_cpu_type_info = {
>      .instance_init = arm_cpu_initfn,
>      .instance_finalize = arm_cpu_finalizefn,
>      .abstract = true,
> -    .class_size = sizeof(ARMCPUClass),
>      .class_init = arm_cpu_class_init,
>  };
>