On Tue, Jun 16, 2026 at 6:40 AM Daniel Henrique Barboza
<[email protected]> wrote:
>
> The sifive_u board does not share the same CPU socket FDT bits from the
> other boards.  In particular the riscv,isa creation is done using either
> CPU0 from soc.e_cpus.harts, and for all other CPUs soc.u_cups.harts is
> used.
>
> It would be too cumbersome to add all these details in the common code
> so we're going to add a special sifive_u only helper that shares the
> common bits with the common helper used by the other boards.
>
> create_fdt_socket_cpu_internal() contains the common bits shared between
> the sifive_u board and the rest.
>
> Signed-off-by: Daniel Henrique Barboza <[email protected]>

Reviewed-by: Alistair Francis <[email protected]>

Alistair

> ---
>  hw/riscv/fdt-common.c | 108 +++++++++++++++++++++++++-----------------
>  1 file changed, 65 insertions(+), 43 deletions(-)
>
> diff --git a/hw/riscv/fdt-common.c b/hw/riscv/fdt-common.c
> index 6c795409a4..70168ad657 100644
> --- a/hw/riscv/fdt-common.c
> +++ b/hw/riscv/fdt-common.c
> @@ -94,28 +94,29 @@ void fdt_create_cpu_socket_subnode(void *fdt, uint64_t 
> timebase_frequency)
>      qemu_fdt_add_subnode(fdt, "/cpus/cpu-map");
>  }
>
> -void create_fdt_socket_cpus(void *fdt, RISCVCPU *socket_harts,
> -                            int socket_id, int num_harts_socket,
> -                            int socket_hartid_base, uint32_t *phandle,
> -                            uint32_t *intc_phandles, bool numa_enabled,
> -                            bool is_32_bit)
> +static void
> +create_fdt_socket_cpu_internal(void *fdt, char *clust_name, RISCVCPU 
> *cpu_ptr,
> +                               int cpu, int socket_id, int 
> socket_hartid_base,
> +                               uint32_t *phandle, uint32_t *intc_phandles,
> +                               bool numa_enabled, bool is_32_bit)
>  {
> -    g_autofree char *clust_name = NULL;
> -    uint32_t cpu_phandle;
> -
> -    clust_name = g_strdup_printf("/cpus/cpu-map/cluster%d", socket_id);
> -    qemu_fdt_add_subnode(fdt, clust_name);
> -
> -    for (int cpu = num_harts_socket - 1; cpu >= 0; cpu--) {
> -        RISCVCPU *cpu_ptr = &socket_harts[cpu];
> +    g_autofree char *cpu_name = NULL;
> +    g_autofree char *core_name = NULL;
> +    g_autofree char *intc_name = NULL;
> +    uint32_t cpu_phandle = (*phandle)++;
> +    bool is_sifive_u = cpu_ptr == NULL;
> +
> +    cpu_name = g_strdup_printf("/cpus/cpu@%d", socket_hartid_base + cpu);
> +
> +    /*
> +     * The sifive_u board has an exclusive satp and riscv,isa
> +     * schema that can't be shared with other boards, so part
> +     * of the CPU FDT creation (i.e. the /cpus/cpu@N subnode)
> +     * is still being done by the board.
> +     */
> +    if (!is_sifive_u) {
>          int8_t satp_mode_max = cpu_ptr->cfg.max_satp_mode;
> -        g_autofree char *cpu_name = NULL;
> -        g_autofree char *core_name = NULL;
> -        g_autofree char *intc_name = NULL;
> -
> -        cpu_phandle = (*phandle)++;
>
> -        cpu_name = g_strdup_printf("/cpus/cpu@%d", socket_hartid_base + cpu);
>          qemu_fdt_add_subnode(fdt, cpu_name);
>
>          if (satp_mode_max != -1) {
> @@ -140,30 +141,51 @@ void create_fdt_socket_cpus(void *fdt, RISCVCPU 
> *socket_harts,
>              qemu_fdt_setprop_cell(fdt, cpu_name, "riscv,cbop-block-size",
>                                    cpu_ptr->cfg.cbop_blocksize);
>          }
> +    }
>
> -        qemu_fdt_setprop_string(fdt, cpu_name, "compatible", "riscv");
> -        qemu_fdt_setprop_string(fdt, cpu_name, "status", "okay");
> -        qemu_fdt_setprop_cell(fdt, cpu_name, "reg",
> -                              socket_hartid_base + cpu);
> -        qemu_fdt_setprop_string(fdt, cpu_name, "device_type", "cpu");
> -        if (numa_enabled) {
> -            qemu_fdt_setprop_cell(fdt, cpu_name, "numa-node-id", socket_id);
> -        }
> -        qemu_fdt_setprop_cell(fdt, cpu_name, "phandle", cpu_phandle);
> -
> -        intc_phandles[cpu] = (*phandle)++;
> -
> -        intc_name = g_strdup_printf("%s/interrupt-controller", cpu_name);
> -        qemu_fdt_add_subnode(fdt, intc_name);
> -        qemu_fdt_setprop_cell(fdt, intc_name, "phandle",
> -                              intc_phandles[cpu]);
> -        qemu_fdt_setprop_string(fdt, intc_name, "compatible",
> -                                "riscv,cpu-intc");
> -        qemu_fdt_setprop(fdt, intc_name, "interrupt-controller", NULL, 0);
> -        qemu_fdt_setprop_cell(fdt, intc_name, "#interrupt-cells", 1);
> -
> -        core_name = g_strdup_printf("%s/core%d", clust_name, cpu);
> -        qemu_fdt_add_subnode(fdt, core_name);
> -        qemu_fdt_setprop_cell(fdt, core_name, "cpu", cpu_phandle);
> +    qemu_fdt_setprop_string(fdt, cpu_name, "compatible", "riscv");
> +    qemu_fdt_setprop_string(fdt, cpu_name, "status", "okay");
> +    qemu_fdt_setprop_cell(fdt, cpu_name, "reg",
> +                          socket_hartid_base + cpu);
> +    qemu_fdt_setprop_string(fdt, cpu_name, "device_type", "cpu");
> +    if (numa_enabled) {
> +        qemu_fdt_setprop_cell(fdt, cpu_name, "numa-node-id", socket_id);
> +    }
> +    qemu_fdt_setprop_cell(fdt, cpu_name, "phandle", cpu_phandle);
> +
> +    intc_phandles[cpu] = (*phandle)++;
> +
> +    intc_name = g_strdup_printf("%s/interrupt-controller", cpu_name);
> +    qemu_fdt_add_subnode(fdt, intc_name);
> +    qemu_fdt_setprop_cell(fdt, intc_name, "phandle",
> +                          intc_phandles[cpu]);
> +    qemu_fdt_setprop_string(fdt, intc_name, "compatible",
> +                            "riscv,cpu-intc");
> +    qemu_fdt_setprop(fdt, intc_name, "interrupt-controller", NULL, 0);
> +    qemu_fdt_setprop_cell(fdt, intc_name, "#interrupt-cells", 1);
> +
> +    core_name = g_strdup_printf("%s/core%d", clust_name, cpu);
> +    qemu_fdt_add_subnode(fdt, core_name);
> +    qemu_fdt_setprop_cell(fdt, core_name, "cpu", cpu_phandle);
> +}
> +
> +void create_fdt_socket_cpus(void *fdt, RISCVCPU *socket_harts,
> +                            int socket_id, int num_harts_socket,
> +                            int socket_hartid_base, uint32_t *phandle,
> +                            uint32_t *intc_phandles, bool numa_enabled,
> +                            bool is_32_bit)
> +{
> +    g_autofree char *clust_name = NULL;
> +
> +    clust_name = g_strdup_printf("/cpus/cpu-map/cluster%d", socket_id);
> +    qemu_fdt_add_subnode(fdt, clust_name);
> +
> +    for (int cpu = num_harts_socket - 1; cpu >= 0; cpu--) {
> +        RISCVCPU *cpu_ptr = &socket_harts[cpu];
> +
> +        create_fdt_socket_cpu_internal(fdt, clust_name, cpu_ptr, cpu,
> +                                       socket_id, socket_hartid_base,
> +                                       phandle, intc_phandles, numa_enabled,
> +                                       is_32_bit);
>      }
>  }
> --
> 2.43.0
>
>

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