[PATCH RFC 21/22] riscv: Switch over to GENERIC_CPU_DEVICES

[Oracle]

From: James Morse <james.morse@xxxxxxx>

Now that GENERIC_CPU_DEVICES calls arch_register_cpu(), which can be
overridden by the arch code, switch over to this to allow common code
to choose when the register_cpu() call is made.

This allows topology_init() to be removed.

This is an intermediate step to the logic being moved to drivers/acpi,
where GENERIC_CPU_DEVICES will do the work when booting with acpi=off.

This patch also has the effect of moving the registration of CPUs from
subsys to driver core initialisation, prior to any initcalls running.

Signed-off-by: James Morse <james.morse@xxxxxxx>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Signed-off-by: Russell King (Oracle) <rmk+kernel@xxxxxxxxxxxxxxx>
---
Changes since RFC v2:
 * Add note about initialisation order change.
---
 arch/riscv/Kconfig        |  1 +
 arch/riscv/kernel/setup.c | 19 ++++---------------
 2 files changed, 5 insertions(+), 15 deletions(-)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index eaa15a20e6ae..264aa466aec3 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -69,6 +69,7 @@ config RISCV
 	select GENERIC_ARCH_TOPOLOGY
 	select GENERIC_ATOMIC64 if !64BIT
 	select GENERIC_CLOCKEVENTS_BROADCAST if SMP
+	select GENERIC_CPU_DEVICES
 	select GENERIC_EARLY_IOREMAP
 	select GENERIC_ENTRY
 	select GENERIC_GETTIMEOFDAY if HAVE_GENERIC_VDSO
diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index 0624f44d43ec..f8875ae1b0aa 100644
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -50,7 +50,6 @@ atomic_t hart_lottery __section(".sdata")
 #endif
 ;
 unsigned long boot_cpu_hartid;
-static DEFINE_PER_CPU(struct cpu, cpu_devices);
 
 /*
  * Place kernel memory regions on the resource tree so that
@@ -295,23 +294,13 @@ void __init setup_arch(char **cmdline_p)
 	riscv_set_dma_cache_alignment();
 }
 
-static int __init topology_init(void)
+int arch_register_cpu(int cpu)
 {
-	int i, ret;
+	struct cpu *c = &per_cpu(cpu_devices, cpu);
 
-	for_each_possible_cpu(i) {
-		struct cpu *cpu = &per_cpu(cpu_devices, i);
-
-		cpu->hotpluggable = cpu_has_hotplug(i);
-		ret = register_cpu(cpu, i);
-		if (unlikely(ret))
-			pr_warn("Warning: %s: register_cpu %d failed (%d)\n",
-			       __func__, i, ret);
-	}
-
-	return 0;
+	c->hotpluggable = cpu_has_hotplug(cpu);
+	return register_cpu(c, cpu);
 }
-subsys_initcall(topology_init);
 
 void free_initmem(void)
 {
-- 
2.30.2