On Fri, Jan 17, 2014 at 12:25:05PM +0000, Hanjun Guo wrote:
> --- a/arch/arm64/kernel/smp.c
> +++ b/arch/arm64/kernel/smp.c
> @@ -48,6 +48,7 @@
> #include <asm/sections.h>
> #include <asm/tlbflush.h>
> #include <asm/ptrace.h>
> +#include <asm/acpi.h>
>
> /*
> * as from 2.5, kernels no longer have an init_tasks structure
> @@ -280,7 +281,7 @@ static void (*smp_cross_call)(const struct cpumask *, unsigned int);
> * cpu logical map array containing MPIDR values related to logical
> * cpus. Assumes that cpu_logical_map(0) has already been initialized.
> */
> -void __init smp_init_cpus(void)
> +static int __init of_smp_init_cpus(void)
> {
> struct device_node *dn = NULL;
> unsigned int i, cpu = 1;
> @@ -364,6 +365,10 @@ next:
> cpu++;
> }
>
> + /* No device tree or no CPU node in DT */
> + if (cpu == 1 && !bootcpu_valid)
> + return -ENODEV;
> +
> /* sanity check */
> if (cpu > NR_CPUS)
> pr_warning("no. of cores (%d) greater than configured maximum of %d - clipping\n",
> @@ -371,7 +376,7 @@ next:
>
> if (!bootcpu_valid) {
> pr_err("DT missing boot CPU MPIDR, not enabling secondaries\n");
> - return;
> + return -EINVAL;
> }
>
> /*
> @@ -381,6 +386,39 @@ next:
> for (i = 0; i < NR_CPUS; i++)
> if (cpu_logical_map(i) != INVALID_HWID)
> set_cpu_possible(i, true);
> +
> + return 0;
> +}
> +
> +/*
> + * In ACPI mode, the cpu possible map was enumerated before SMP
> + * initialization when MADT table was parsed, so we can get the
> + * possible map here to initialize CPUs.
> + */
> +static void __init acpi_smp_init_cpus(void)
> +{
> + int cpu;
> + const char *enable_method;
> +
> + for_each_possible_cpu(cpu) {
> + enable_method = acpi_get_enable_method(cpu);
> + if (!enable_method)
> + continue;
> +
> + cpu_ops[cpu] = cpu_get_ops(enable_method);
> + if (!cpu_ops[cpu])
> + continue;
> +
> + cpu_ops[cpu]->cpu_init(NULL, cpu);
> + }
> +}
> +
> +void __init smp_init_cpus(void)
> +{
> + if (!of_smp_init_cpus())
> + return;
> +
> + acpi_smp_init_cpus();
> }
With DT we initialise the cpu_ops[0] via cpu_read_bootcpu_ops() called
from setup_arch(). This is needed because with PSCI we use cpu_ops for
power management even if it's a UP system. Do you get a some kernel
warning about device node for the boot cpu not found?
> --- a/drivers/acpi/plat/arm-core.c
> +++ b/drivers/acpi/plat/arm-core.c
> @@ -367,6 +367,32 @@ static void __init acpi_process_madt(void)
> }
>
> /*
> + * To see PCSI is enabled or not.
> + *
> + * PSCI is not available for ACPI 5.0, return FALSE for now.
> + *
> + * FIXME: should we introduce early_param("psci", func) for test purpose?
> + */
> +static bool acpi_psci_smp_available(int cpu)
> +{
> + return FALSE;
> +}
> +
> +static const char *enable_method[] = {
> + "psci",
> + "spin-table",
> + NULL
> +};
> +
> +const char *acpi_get_enable_method(int cpu)
> +{
> + if (acpi_psci_smp_available(cpu))
> + return enable_method[0];
> + else
> + return enable_method[1];
> +}
You could just use literal strings here, actually even ignoring PSCI
until available.
--
Catalin
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