arm64: kernel: remove ARM64_CPU_SUSPEND config option

ARM64_CPU_SUSPEND config option was introduced to make code providing
context save/restore selectable only on platforms requiring power
management capabilities.

Currently ARM64_CPU_SUSPEND depends on the PM_SLEEP config option which
in turn is set by the SUSPEND config option.

The introduction of CPU_IDLE for arm64 requires that code configured
by ARM64_CPU_SUSPEND (context save/restore) should be compiled in
in order to enable the CPU idle driver to rely on CPU operations
carrying out context save/restore.

The ARM64_CPUIDLE config option (ARM64 generic idle driver) is therefore
forced to select ARM64_CPU_SUSPEND, even if there may be (ie PM_SLEEP)
failed dependencies, which is not a clean way of handling the kernel
configuration option.

For these reasons, this patch removes the ARM64_CPU_SUSPEND config option
and makes the context save/restore dependent on CPU_PM, which is selected
whenever either SUSPEND or CPU_IDLE are configured, cleaning up dependencies
in the process.

This way, code previously configured through ARM64_CPU_SUSPEND is
compiled in whenever a power management subsystem requires it to be
present in the kernel (SUSPEND || CPU_IDLE), which is the behaviour
expected on ARM64 kernels.

The cpu_suspend and cpu_init_idle CPU operations are added only if
CPU_IDLE is selected, since they are CPU_IDLE specific methods and
should be grouped and defined accordingly.

PSCI CPU operations are updated to reflect the introduced changes.

Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

6 files changed, 23 insertions, 26 deletions

diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 3b3b1cd3e7f0..bef04afd6031 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -27,7 +27,7 @@ arm64-obj-$(CONFIG_SMP)			+= smp.o smp_spin_table.o topology.o
 arm64-obj-$(CONFIG_PERF_EVENTS)         += perf_regs.o
 arm64-obj-$(CONFIG_HW_PERF_EVENTS)      += perf_event.o
 arm64-obj-$(CONFIG_HAVE_HW_BREAKPOINT)  += hw_breakpoint.o
-arm64-obj-$(CONFIG_ARM64_CPU_SUSPEND)   += sleep.o suspend.o
+arm64-obj-$(CONFIG_CPU_PM)              += sleep.o suspend.o
 arm64-obj-$(CONFIG_CPU_IDLE)            += cpuidle.o
 arm64-obj-$(CONFIG_JUMP_LABEL)          += jump_label.o
 arm64-obj-$(CONFIG_KGDB)                += kgdb.o
diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
index 9a9fce090d58..a2ae19403abb 100644
--- a/arch/arm64/kernel/asm-offsets.c
+++ b/arch/arm64/kernel/asm-offsets.c
@@ -152,7 +152,7 @@ int main(void)
   DEFINE(KVM_VTTBR,             offsetof(struct kvm, arch.vttbr));
   DEFINE(KVM_VGIC_VCTRL,        offsetof(struct kvm, arch.vgic.vctrl_base));
 #endif
-#ifdef CONFIG_ARM64_CPU_SUSPEND
+#ifdef CONFIG_CPU_PM
   DEFINE(CPU_SUSPEND_SZ,        sizeof(struct cpu_suspend_ctx));
   DEFINE(CPU_CTX_SP,            offsetof(struct cpu_suspend_ctx, sp));
   DEFINE(MPIDR_HASH_MASK,       offsetof(struct mpidr_hash, mask));
diff --git a/arch/arm64/kernel/cpuidle.c b/arch/arm64/kernel/cpuidle.c
index 19d17f51db37..5c0896647fd1 100644
--- a/arch/arm64/kernel/cpuidle.c
+++ b/arch/arm64/kernel/cpuidle.c
@@ -29,3 +29,23 @@ int cpu_init_idle(unsigned int cpu)
         of_node_put(cpu_node);
         return ret;
 }
+
+/**
+ * cpu_suspend() - function to enter a low-power idle state
+ * @arg: argument to pass to CPU suspend operations
+ *
+ * Return: 0 on success, -EOPNOTSUPP if CPU suspend hook not initialized, CPU
+ * operations back-end error code otherwise.
+ */
+int cpu_suspend(unsigned long arg)
+{
+        int cpu = smp_processor_id();
+
+        /*
+         * If cpu_ops have not been registered or suspend
+         * has not been initialized, cpu_suspend call fails early.
+         */
+        if (!cpu_ops[cpu] || !cpu_ops[cpu]->cpu_suspend)
+                return -EOPNOTSUPP;
+        return cpu_ops[cpu]->cpu_suspend(arg);
+}
diff --git a/arch/arm64/kernel/hw_breakpoint.c b/arch/arm64/kernel/hw_breakpoint.c
index df1cf15377b4..98bbe06e469c 100644
--- a/arch/arm64/kernel/hw_breakpoint.c
+++ b/arch/arm64/kernel/hw_breakpoint.c
@@ -894,7 +894,7 @@ static struct notifier_block hw_breakpoint_reset_nb = {
         .notifier_call = hw_breakpoint_reset_notify,
 };
 
-#ifdef CONFIG_ARM64_CPU_SUSPEND
+#ifdef CONFIG_CPU_PM
 extern void cpu_suspend_set_dbg_restorer(void (*hw_bp_restore)(void *));
 #else
 static inline void cpu_suspend_set_dbg_restorer(void (*hw_bp_restore)(void *))
diff --git a/arch/arm64/kernel/psci.c b/arch/arm64/kernel/psci.c
index f1dbca7d5c96..3425f311c49e 100644
--- a/arch/arm64/kernel/psci.c
+++ b/arch/arm64/kernel/psci.c
@@ -540,8 +540,6 @@ const struct cpu_operations cpu_psci_ops = {
         .name           = "psci",
 #ifdef CONFIG_CPU_IDLE
         .cpu_init_idle  = cpu_psci_cpu_init_idle,
-#endif
-#ifdef CONFIG_ARM64_CPU_SUSPEND
         .cpu_suspend    = cpu_psci_cpu_suspend,
 #endif
 #ifdef CONFIG_SMP
diff --git a/arch/arm64/kernel/suspend.c b/arch/arm64/kernel/suspend.c
index 2d6b6065fe7f..d7daf45ae7a2 100644
--- a/arch/arm64/kernel/suspend.c
+++ b/arch/arm64/kernel/suspend.c
@@ -1,7 +1,6 @@
 #include <linux/percpu.h>
 #include <linux/slab.h>
 #include <asm/cacheflush.h>
-#include <asm/cpu_ops.h>
 #include <asm/debug-monitors.h>
 #include <asm/pgtable.h>
 #include <asm/memory.h>
@@ -51,26 +50,6 @@ void __init cpu_suspend_set_dbg_restorer(void (*hw_bp_restore)(void *))
         hw_breakpoint_restore = hw_bp_restore;
 }
 
-/**
- * cpu_suspend() - function to enter a low-power state
- * @arg: argument to pass to CPU suspend operations
- *
- * Return: 0 on success, -EOPNOTSUPP if CPU suspend hook not initialized, CPU
- * operations back-end error code otherwise.
- */
-int cpu_suspend(unsigned long arg)
-{
-        int cpu = smp_processor_id();
-
-        /*
-         * If cpu_ops have not been registered or suspend
-         * has not been initialized, cpu_suspend call fails early.
-         */
-        if (!cpu_ops[cpu] || !cpu_ops[cpu]->cpu_suspend)
-                return -EOPNOTSUPP;
-        return cpu_ops[cpu]->cpu_suspend(arg);
-}
-
 /*
  * __cpu_suspend
  *