Re: [PATCH v4 11/11] target/loongarch: Add loongarch32 cpu la132

[Jiajie Chen]

On 2023/8/9 03:26, Richard Henderson wrote:
> On 8/7/23 18:54, Jiajie Chen wrote:
> > +static void loongarch_la464_initfn(Object *obj)
> > +{
> > +    LoongArchCPU *cpu = LOONGARCH_CPU(obj);
> > +    CPULoongArchState *env = &cpu->env;
> > +
> > +    loongarch_cpu_initfn_common(env);
> > +
> > +    cpu->dtb_compatible = "loongarch,Loongson-3A5000";
> > +    env->cpucfg[0] = 0x14c010;  /* PRID */
> > +
> > +    uint32_t data = env->cpucfg[1];
> > +    data = FIELD_DP32(data, CPUCFG1, ARCH, 2); /* LA64 */
> > +    data = FIELD_DP32(data, CPUCFG1, PALEN, 0x2f); /* 48 bits */
> > +    data = FIELD_DP32(data, CPUCFG1, VALEN, 0x2f); /* 48 bits */
> > +    data = FIELD_DP32(data, CPUCFG1, RI, 1);
> > +    data = FIELD_DP32(data, CPUCFG1, EP, 1);
> > +    data = FIELD_DP32(data, CPUCFG1, RPLV, 1);
> > +    env->cpucfg[1] = data;
> > +}
> > +
> > +static void loongarch_la132_initfn(Object *obj)
> > +{
> > +    LoongArchCPU *cpu = LOONGARCH_CPU(obj);
> > +    CPULoongArchState *env = &cpu->env;
> > +
> > +    loongarch_cpu_initfn_common(env);
> > +
> > +    cpu->dtb_compatible = "loongarch,Loongson-1C103";
> > +
> > +    uint32_t data = env->cpucfg[1];
> > +    data = FIELD_DP32(data, CPUCFG1, ARCH, 1); /* LA32 */
> > +    data = FIELD_DP32(data, CPUCFG1, PALEN, 0x1f); /* 32 bits */
> > +    data = FIELD_DP32(data, CPUCFG1, VALEN, 0x1f); /* 32 bits */
> > +    data = FIELD_DP32(data, CPUCFG1, RI, 0);
> > +    data = FIELD_DP32(data, CPUCFG1, EP, 0);
> > +    data = FIELD_DP32(data, CPUCFG1, RPLV, 0);
> > +    env->cpucfg[1] = data;
> > +}
>
> The use of the loongarch_cpu_initfn_common function is not going to 
> scale.
> Compare the set of *_initfn in target/arm/tcg/cpu32.c
>
> In general, you want to copy data in bulk from the processor manual, 
> so that the reviewer can simply read through the table and see that 
> the code is correct, without having to check between multiple 
> functions to see that the combination is correct.
>
> For our existing la464, that table is Table 54 in the 3A5000 manual.
>
> Is there a public specification for the la132?  I could not find one 
> in https://www.loongson.cn/EN/product/, but perhaps that's just the 
> english view.


There seems no, even from the chinese view.


> r~