Re: [PATCH v3 13/18] target/loongarch: Add loongarch32 cpu la132

[Philippe Mathieu-Daudé]

On 17/8/23 11:31, Song Gao wrote:
> From: Jiajie Chen <c@jia.je>
>
> Add la132 as a loongarch32 cpu type and allow virt machine to be used
> with la132 instead of la464.
>
> Due to lack of public documentation of la132, it is currently a
> synthetic loongarch32 cpu model. Details need to be added in the future.
>
> Signed-off-by: Jiajie Chen <c@jia.je>
> Acked-by: Richard Henderson <richard.henderson@linaro.org>
> Signed-off-by: Song Gao <gaosong@loongson.cn>
> ---
>   hw/loongarch/virt.c    |  5 -----
>   target/loongarch/cpu.c | 29 +++++++++++++++++++++++++++++
>   2 files changed, 29 insertions(+), 5 deletions(-)
>
> diff --git a/target/loongarch/cpu.c b/target/loongarch/cpu.c
> index 8d95c997dc..95e00a044c 100644
> --- a/target/loongarch/cpu.c
> +++ b/target/loongarch/cpu.c


> +static void loongarch_la132_initfn(Object *obj)
> +{
> +    LoongArchCPU *cpu = LOONGARCH_CPU(obj);
> +    CPULoongArchState *env = &cpu->env;
> +
> +    int i;
> +
> +    for (i = 0; i < 21; i++) {
> +        env->cpucfg[i] = 0x0;
> +    }
> +
> +    cpu->dtb_compatible = "loongarch,Loongson-1C103";
> +
> +    uint32_t data = 0;
> +    data = FIELD_DP32(data, CPUCFG1, ARCH, 1); /* LA32 */
> +    data = FIELD_DP32(data, CPUCFG1, PGMMU, 1);
> +    data = FIELD_DP32(data, CPUCFG1, IOCSR, 1);
> +    data = FIELD_DP32(data, CPUCFG1, PALEN, 0x1f); /* 32 bits */
> +    data = FIELD_DP32(data, CPUCFG1, VALEN, 0x1f); /* 32 bits */
> +    data = FIELD_DP32(data, CPUCFG1, UAL, 1);
> +    data = FIELD_DP32(data, CPUCFG1, RI, 0);
> +    data = FIELD_DP32(data, CPUCFG1, EP, 0);
> +    data = FIELD_DP32(data, CPUCFG1, RPLV, 0);
> +    data = FIELD_DP32(data, CPUCFG1, HP, 1);
> +    data = FIELD_DP32(data, CPUCFG1, IOCSR_BRD, 1);
> +    env->cpucfg[1] = data;

So we have PRid = env->cpucfg[0] = 0...

The LA132 series is 0x8000, so we can use smth like:

       env->cpucfg[0] = 0x148042;  /* PRID */

> +}
> +
>   static void loongarch_cpu_list_entry(gpointer data, gpointer user_data)
>   {
>       const char *typename = object_class_get_name(OBJECT_CLASS(data));
> @@ -779,6 +807,7 @@ static const TypeInfo loongarch_cpu_type_infos[] = {
>           .class_init = loongarch32_cpu_class_init,
>       },
>       DEFINE_LOONGARCH_CPU_TYPE("la464", loongarch_la464_initfn),
> +    DEFINE_LOONGARCH32_CPU_TYPE("la132", loongarch_la132_initfn),
>   };

CPUNAME_REG in loongarch_qemu_read() is likely incorrect, but not a
big deal.