Re: [PATCH 13/24] RISC-V: ACPI: smpboot: Add ACPI support in smp_setup()

Conor Dooley
2023-02-08T22:10:23Z

[-- Attachment #1: Type: text/plain, Size: 4761 bytes --]

On Mon, Jan 30, 2023 at 11:52:14PM +0530, Sunil V L wrote:
> Add function to parse the RINTC structure in
> the MADT table and create the required initializations to
> enable SMP boot on ACPI based platforms.
>
> Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
> ---
> arch/riscv/include/asm/acpi.h | 7 ++++
> arch/riscv/kernel/smpboot.c | 73 ++++++++++++++++++++++++++++++++++-
> 2 files changed, 79 insertions(+), 1 deletion(-)
>
> diff --git a/arch/riscv/include/asm/acpi.h b/arch/riscv/include/asm/acpi.h
> index c5cb9f96d404..d1f1e53ec657 100644
> --- a/arch/riscv/include/asm/acpi.h
> +++ b/arch/riscv/include/asm/acpi.h
> @@ -58,6 +58,13 @@ static inline bool acpi_has_cpu_in_madt(void)
> }
>
> static inline void arch_fix_phys_package_id(int num, u32 slot) { }
> +
> +#ifdef CONFIG_ACPI_NUMA
> +int acpi_numa_get_nid(unsigned int cpu);
> +#else
> +static inline int acpi_numa_get_nid(unsigned int cpu) { return NUMA_NO_NODE; }
> +#endif /* CONFIG_ACPI_NUMA */
> +
> #endif
>
> #endif /*_ASM_ACPI_H*/
> diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
> index 26214ddefaa4..e48cf88d0bc1 100644
> --- a/arch/riscv/kernel/smpboot.c
> +++ b/arch/riscv/kernel/smpboot.c
> @@ -8,6 +8,7 @@
> * Copyright (C) 2017 SiFive
> */
>
> +#include <linux/acpi.h>
> #include <linux/arch_topology.h>
> #include <linux/module.h>
> #include <linux/init.h>
> @@ -70,6 +71,73 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
> }
> }
>
> +#ifdef CONFIG_ACPI
> +static unsigned int cpu_count = 1;
> +
> +static int __init
> +acpi_parse_rintc(union acpi_subtable_headers *header,
> + const unsigned long end)

This all fits on one line. And also avoids the checkpatch complaint from
what you have currently done...

> +{
> + unsigned long hart;
> + bool found_boot_cpu = false;
> +
> + struct acpi_madt_rintc *processor;
> +
> + processor = (struct acpi_madt_rintc *)header;

Why not combine the above two lines?

> + /* RINTC entry which has !ACPI_MADT_ENABLED is not enabled so skip */

This comment is a bit -ENOPARSE. Please reword it in a way that is
understandable to mere mortals like myself.

> + if (!(processor->flags & ACPI_MADT_ENABLED))
> + return 0;
> +
> + hart = processor->hart_id;
> + if (hart < 0)
> + return 0;

Newline here please

> + if (hart == cpuid_to_hartid_map(0)) {
> + BUG_ON(found_boot_cpu);
> + found_boot_cpu = 1;

This is a bool, why not assign a bool value to it so it looks more
intentional? I know this is copied from the dt code, but that should
really be on too IMO.

> + early_map_cpu_to_node(0, acpi_numa_get_nid(cpu_count));
> + return 0;
> + }

And a newline here too...

> + if (cpu_count >= NR_CPUS) {
> + pr_warn("Invalid cpuid [%d] for hartid [%lu]\n",
> + cpu_count, hart);
> + return 0;
> + }
> +
> + cpuid_to_hartid_map(cpu_count) = hart;
> + early_map_cpu_to_node(cpu_count, acpi_numa_get_nid(cpu_count));
> + cpu_count++;

...and also here please!

> + return 0;
> +}
> +
> +static void __init acpi_parse_and_init_cpus(void)
> +{
> + int cpuid;
> +
> + cpu_set_ops(0);

While I'm at it suggesting newline additions, adding them before
comments would be great too.

> + /*
> + * do a walk of MADT to determine how many CPUs
> + * we have including disabled CPUs, and get information
> + * we need for SMP init.
> + */
> + acpi_table_parse_madt(ACPI_MADT_TYPE_RINTC,
> + acpi_parse_rintc, 0);
> +
> + /*
> + * NUMA - TODO
> + */

TODO before merging, or TODO at some indeterminate point in the future?

Anyways, this is all nits & this largely seem to resemble the dt code,
so with the nits fixed (and an s/ACPI: // in $subject):
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>

Cheers,
Conor.

> + for (cpuid = 1; cpuid < nr_cpu_ids; cpuid++) {
> + if (cpuid_to_hartid_map(cpuid) != INVALID_HARTID) {
> + cpu_set_ops(cpuid);
> + set_cpu_possible(cpuid, true);
> + }
> + }
> +}
> +#else
> +#define acpi_parse_and_init_cpus(...) do { } while (0)
> +#endif
> +
> static void __init of_parse_and_init_cpus(void)
> {
> struct device_node *dn;
> @@ -118,7 +186,10 @@ static void __init of_parse_and_init_cpus(void)
>
> void __init setup_smp(void)
> {
> - of_parse_and_init_cpus();
> + if (acpi_disabled)
> + of_parse_and_init_cpus();
> + else
> + acpi_parse_and_init_cpus();
> }
>
> static int start_secondary_cpu(int cpu, struct task_struct *tidle)
> --
> 2.38.0
>
>
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]