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SubjectRe: [PATCH 11/20] ARM64 / ACPI: Get the enable method for SMP initialization
Hi Catalin,

On 2014年01月24日 01:50, Catalin Marinas wrote:
> 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?

Thanks for pointing this out, actually we didn't find a dts file with
spin-table method for SMP initialization, and this patch is not fully
tested (only spin-table method is supported in ACPI now), we are
working on that and get this patch fully tested.

I will review the code carefully in your comments, and update
the code accordingly.

>
>> --- 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.

Ok.

Thanks
Hanjun

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