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

[Richard Henderson <richard.henderson@linaro.org>]

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.


r~