[PATCH 09/12] firmware: psci: Replace cpu_up/down with device_online/offline

Qais Yousef
2019-10-30T15:42:49Z

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@arm.com>
CC: Mark Rutland <mark.rutland@arm.com>
CC: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
CC: linux-arm-kernel@lists.infradead.org
CC: linux-kernel@vger.kernel.org
---
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