[PATCH v2 11/14] firmware: psci: Replace cpu_up/down with device_online/offline

[Qais Yousef]

The core device API performs extra housekeeping bits that are missing
from directly calling cpu_up/down.

See commit a6717c01ddc2 ("powerpc/rtas: use device model APIs and
serialization during LPM") for an example description of what might go
wrong.

This also prepares to make cpu_up/down a private interface for anything
but the cpu subsystem.

Signed-off-by: Qais Yousef <qais.yousef@xxxxxxx>
CC: Mark Rutland <mark.rutland@xxxxxxx>
CC: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
CC: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
CC: linux-kernel@xxxxxxxxxxxxxxx
---
 drivers/firmware/psci/psci_checker.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/firmware/psci/psci_checker.c b/drivers/firmware/psci/psci_checker.c
index 6a445397771c..9e4b1bade659 100644
--- a/drivers/firmware/psci/psci_checker.c
+++ b/drivers/firmware/psci/psci_checker.c
@@ -83,8 +83,9 @@ static unsigned int down_and_up_cpus(const struct cpumask *cpus,
 	cpumask_clear(offlined_cpus);
 
 	/* Try to power down all CPUs in the mask. */
+	lock_device_hotplug();
 	for_each_cpu(cpu, cpus) {
-		int ret = cpu_down(cpu);
+		int ret = device_offline(get_cpu_device(cpu));
 
 		/*
 		 * cpu_down() checks the number of online CPUs before the TOS
@@ -116,7 +117,7 @@ static unsigned int down_and_up_cpus(const struct cpumask *cpus,
 
 	/* Try to power up all the CPUs that have been offlined. */
 	for_each_cpu(cpu, offlined_cpus) {
-		int ret = cpu_up(cpu);
+		int ret = device_online(get_cpu_device(cpu));
 
 		if (ret != 0) {
 			pr_err("Error occurred (%d) while trying "
@@ -126,6 +127,7 @@ static unsigned int down_and_up_cpus(const struct cpumask *cpus,
 			cpumask_clear_cpu(cpu, offlined_cpus);
 		}
 	}
+	unlock_device_hotplug();
 
 	/*
 	 * Something went bad at some point and some CPUs could not be turned
-- 
2.17.1