[PATCH v2 12/16] cpu: Add loongarch_cpu driver

[Simon Glass]

Hi Jiaxun,

On 2026-07-01T11:17:53, Yao Zi <me at ziyao.cc> wrote:
> cpu: Add loongarch_cpu driver
>
> Implement a driver for LoongArch CPU solely for gathering
> some information bits from FDT and CPU level config registers.
>
> Signed-off-by: Jiaxun Yang <jiaxun.yang at flygoat.com>
> Signed-off-by: Yao Zi <me at ziyao.cc>
>
> drivers/cpu/Kconfig         |   6 ++
>  drivers/cpu/Makefile        |   1 +
>  drivers/cpu/loongarch_cpu.c | 148 ++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 155 insertions(+)

> diff --git a/drivers/cpu/loongarch_cpu.c b/drivers/cpu/loongarch_cpu.c
> @@ -0,0 +1,148 @@
> +static int loongarch_cpu_get_desc(const struct udevice *dev, char *buf, int size)
> +{
> +     const char *cpu;
> +
> +     /* We try to get CPU name from IOCSR first */
> +     if ((read_cpucfg(LOONGARCH_CPUCFG1) & CPUCFG1_IOCSR)) {
> +             int i;
> +             char vendor_buf[9] = { 0 };
> +             char name_buf[9] = { 0 };
> +             u64 vendor = iocsr_read64(LOONGARCH_IOCSR_VENDOR);
> +             u64 name = iocsr_read64(LOONGARCH_IOCSR_CPUNAME);
> +
> +             if (!vendor || !name)
> +                     goto get_desc_dt;
> +
> +             for (i = 0; i < sizeof(u64); i++) {
> +                     vendor_buf[i] = vendor & 0xff;
> +                     name_buf[i] = name & 0xff;
> +                     vendor >>= 8;
> +                     name >>= 8;
> +             }
> +
> +             snprintf(buf, size, '%s-%s', vendor_buf, name_buf);
> +
> +             return 0;
> +     }
> +
> +get_desc_dt:
> +     cpu = dev_read_string(dev, 'compatible');

Please drop the goto - it jumps out of an if-body to a label at the
same scope. Close the if-body when the IOCSR read is valid and let
the DT path fall through.

Also, snprintf() can silently truncate if size is smaller than the
composed string; please return -ENOSPC in that case, similar to the
DT branch below.

Regards,
Simon