[RFC 2/4] arch-topology: add a default implementation of store_cpu_topology()

From: Conor Dooley <mail@conchuod.ie>
To: Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Palmer Dabbelt <palmer@rivosinc.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Sudeep Holla <sudeep.holla@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"Rafael J . Wysocki" <rafael@kernel.org>
Cc: Daire McNamara <daire.mcnamara@microchip.com>,
	Conor Dooley <conor.dooley@microchip.com>,
	Niklas Cassel <niklas.cassel@wdc.com>,
	Damien Le Moal <damien.lemoal@opensource.wdc.com>,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	Zong Li <zong.li@sifive.com>,
	Emil Renner Berthing <kernel@esmil.dk>,
	Jonas Hahnfeld <hahnjo@hahnjo.de>, Guo Ren <guoren@kernel.org>,
	Anup Patel <anup@brainfault.org>,
	Atish Patra <atishp@atishpatra.org>,
	Changbin Du <changbin.du@intel.com>,
	Heiko Stuebner <heiko@sntech.de>,
	Philipp Tomsich <philipp.tomsich@vrull.eu>,
	Rob Herring <robh@kernel.org>, Marc Zyngier <maz@kernel.org>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	Brice Goglin <Brice.Goglin@inria.fr>
Subject: [RFC 2/4] arch-topology: add a default implementation of store_cpu_topology()
Date: Thu,  7 Jul 2022 23:04:35 +0100	[thread overview]
Message-ID: <20220707220436.4105443-3-mail@conchuod.ie> (raw)
In-Reply-To: <20220707220436.4105443-1-mail@conchuod.ie>

From: Conor Dooley <conor.dooley@microchip.com>

RISC-V & arm64 both use an almost identical method of filling in
default vales for arch topology. Create a weakly defined default
implementation with the intent of migrating both archs to use it.

Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
---
 drivers/base/arch_topology.c  | 19 +++++++++++++++++++
 include/linux/arch_topology.h |  1 +
 2 files changed, 20 insertions(+)

diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c
index 441e14ac33a4..07e84c6ac5c2 100644
--- a/drivers/base/arch_topology.c
+++ b/drivers/base/arch_topology.c
@@ -765,6 +765,25 @@ void update_siblings_masks(unsigned int cpuid)
 	}
 }
 
+void __weak store_cpu_topology(unsigned int cpuid)
+{
+	struct cpu_topology *cpuid_topo = &cpu_topology[cpuid];
+
+	if (cpuid_topo->package_id != -1)
+		goto topology_populated;
+
+	cpuid_topo->thread_id = -1;
+	cpuid_topo->core_id = cpuid;
+	cpuid_topo->package_id = cpu_to_node(cpuid);
+
+	pr_debug("CPU%u: package %d core %d thread %d\n",
+		 cpuid, cpuid_topo->package_id, cpuid_topo->core_id,
+		 cpuid_topo->thread_id);
+
+topology_populated:
+	update_siblings_masks(cpuid);
+}
+
 static void clear_cpu_topology(int cpu)
 {
 	struct cpu_topology *cpu_topo = &cpu_topology[cpu];
diff --git a/include/linux/arch_topology.h b/include/linux/arch_topology.h
index a07b510e7dc5..fee306b8a541 100644
--- a/include/linux/arch_topology.h
+++ b/include/linux/arch_topology.h
@@ -92,6 +92,7 @@ void update_siblings_masks(unsigned int cpu);
 void remove_cpu_topology(unsigned int cpuid);
 void reset_cpu_topology(void);
 int parse_acpi_topology(void);
+
 #endif
 
 #endif /* _LINUX_ARCH_TOPOLOGY_H_ */
-- 
2.37.0


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