On 13.06.2025 17:48, Oleksii Kurochko wrote:
> Implements dt_processor_hartid() to get the hart ID of the given
> device tree node and do some checks if CPU is available and given device
> tree node has proper riscv,isa property.
>
> As a helper function dt_get_hartid() is introduced to deal specifically
> with reg propery of a CPU device node.
>
> Signed-off-by: Oleksii Kurochko <oleksii.kuroc...@gmail.com>
Acked-by: Jan Beulich <jbeul...@suse.com>
> @@ -14,3 +17,77 @@ void __init smp_prepare_boot_cpu(void)
> cpumask_set_cpu(0, &cpu_possible_map);
> cpumask_set_cpu(0, &cpu_online_map);
> }
> +
> +/**
> + * dt_get_hartid - Get the hartid from a CPU device node
> + *
> + * @cpun: CPU number(logical index) for which device node is required
> + *
> + * Return: The hartid for the CPU node or ~0UL if not found.
> + */
> +static unsigned long dt_get_hartid(const struct dt_device_node *cpun)
> +{
> + const __be32 *cell;
> + unsigned int ac;
> + uint32_t len;
> +
> + ac = dt_n_addr_cells(cpun);
> + cell = dt_get_property(cpun, "reg", &len);
I'll commit as is, but I'd like to note that such could be more compact:
unsigned int ac = dt_n_addr_cells(cpun);
uint32_t len;
const __be32 *cell = dt_get_property(cpun, "reg", &len);
> + /*
> + * If ac > 2, the result may be truncated or meaningless unless
> + * dt_read_number() supports wider integers.
> + *
> + * TODO: drop (ac > 2) when dt_read_number() will support wider
> + * integers.
> + */
> + if ( !cell || !ac || (ac > 2) || (ac > len / sizeof(*cell)) )
> + return ~0UL;
> +
> + return dt_read_number(cell, ac);
I'd further like to note that this will silently truncate from 64 to 32
bits (when ac == 2) for RV32.
Jan
