ARM: 8063/1: bL_switcher: fix individual online status reporting of removed CPUs

The content of /sys/devices/system/cpu/cpu*/online  is still 1 for those
CPUs that the switcher has removed even though the global state in
/sys/devices/system/cpu/online is updated correctly.

It turns out that commit 0902a9044f ("Driver core: Use generic
offline/online for CPU offline/online") has changed the way those files
retrieve their content by relying on on the generic attribute handling
code.  The switcher, by calling cpu_down() directly, bypasses this
handling and the attribute value doesn't get updated.

Fix this by calling device_offline()/device_online() instead.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 7 insertions, 3 deletions

diff --git a/arch/arm/common/bL_switcher.c b/arch/arm/common/bL_switcher.c
index f01c0ee0c87e..490f3dced749 100644
--- a/arch/arm/common/bL_switcher.c
+++ b/arch/arm/common/bL_switcher.c
@@ -433,8 +433,12 @@ static void bL_switcher_restore_cpus(void)
 {
         int i;
 
-        for_each_cpu(i, &bL_switcher_removed_logical_cpus)
-                cpu_up(i);
+        for_each_cpu(i, &bL_switcher_removed_logical_cpus) {
+                struct device *cpu_dev = get_cpu_device(i);
+                int ret = device_online(cpu_dev);
+                if (ret)
+                        dev_err(cpu_dev, "switcher: unable to restore CPU\n");
+        }
 }
 
 static int bL_switcher_halve_cpus(void)
@@ -521,7 +525,7 @@ static int bL_switcher_halve_cpus(void)
                         continue;
                 }
 
-                ret = cpu_down(i);
+                ret = device_offline(get_cpu_device(i));
                 if (ret) {
                         bL_switcher_restore_cpus();
                         return ret;