Commit 2f0a5d10 authored by Jeremy Linton's avatar Jeremy Linton Committed by Catalin Marinas
Browse files

arm64: topology: enable ACPI/PPTT based CPU topology 



Propagate the topology information from the PPTT tree to the
cpu_topology array. We can get the thread id and core_id by assuming
certain levels of the PPTT tree correspond to those concepts.
The package_id is flagged in the tree and can be found by calling
find_acpi_cpu_topology_package() which terminates
its search when it finds an ACPI node flagged as the physical
package. If the tree doesn't contain enough levels to represent
all of the requested levels then the root node will be returned
for all subsequent levels.

Tested-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: default avatarVijaya Kumar K <vkilari@codeaurora.org>
Tested-by: default avatarXiongfeng Wang <wangxiongfeng2@huawei.com>
Tested-by: default avatarTomasz Nowicki <Tomasz.Nowicki@cavium.com>
Acked-by: default avatarSudeep Holla <sudeep.holla@arm.com>
Acked-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: default avatarMorten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: default avatarJeremy Linton <jeremy.linton@arm.com>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 868abc07

arch/arm64/kernel/topology.c

+44 −1
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
 * for more details.

 */



#include <linux/acpi.h>

#include <linux/arch_topology.h>

#include <linux/cpu.h>

#include <linux/cpumask.h>
@@ -22,6 +23,7 @@ 
#include <linux/sched.h>

#include <linux/sched/topology.h>

#include <linux/slab.h>

#include <linux/smp.h>

#include <linux/string.h>



#include <asm/cpu.h>
@@ -296,6 +298,45 @@ static void __init reset_cpu_topology(void) 
	}

}



#ifdef CONFIG_ACPI

/*

 * Propagate the topology information of the processor_topology_node tree to the

 * cpu_topology array.

 */

static int __init parse_acpi_topology(void)

{

	bool is_threaded;

	int cpu, topology_id;



	is_threaded = read_cpuid_mpidr() & MPIDR_MT_BITMASK;



	for_each_possible_cpu(cpu) {

		topology_id = find_acpi_cpu_topology(cpu, 0);

		if (topology_id < 0)

			return topology_id;



		if (is_threaded) {

			cpu_topology[cpu].thread_id = topology_id;

			topology_id = find_acpi_cpu_topology(cpu, 1);

			cpu_topology[cpu].core_id   = topology_id;

		} else {

			cpu_topology[cpu].thread_id  = -1;

			cpu_topology[cpu].core_id    = topology_id;

		}

		topology_id = find_acpi_cpu_topology_package(cpu);

		cpu_topology[cpu].package_id = topology_id;

	}



	return 0;

}



#else

static inline int __init parse_acpi_topology(void)

{

	return -EINVAL;

}

#endif



void __init init_cpu_topology(void)

{

	reset_cpu_topology();
@@ -304,6 +345,8 @@ void __init init_cpu_topology(void) 
	 * Discard anything that was parsed if we hit an error so we

	 * don't use partial information.

	 */

	if (of_have_populated_dt() && parse_dt_topology())

	if (!acpi_disabled && parse_acpi_topology())

		reset_cpu_topology();

	else if (of_have_populated_dt() && parse_dt_topology())

		reset_cpu_topology();

}

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