arm/bL_switcher: Convert to hotplug state machine

Install the callbacks via the state machine.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: rt@linuxtronix.de
Cc: linux-arm-kernel@lists.infradead.org
Cc: Russell King <linux@armlinux.org.uk>
Link: http://lkml.kernel.org/r/20161117183541.8588-15-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

2 files changed, 21 insertions, 14 deletions

diff --git a/arch/arm/common/bL_switcher.c b/arch/arm/common/bL_switcher.c
index 37dc0fe1093f..46730017b3c5 100644
--- a/arch/arm/common/bL_switcher.c
+++ b/arch/arm/common/bL_switcher.c
@@ -757,19 +757,18 @@ EXPORT_SYMBOL_GPL(bL_switcher_put_enabled);
  * while the switcher is active.
  * We're just not ready to deal with that given the trickery involved.
  */
-static int bL_switcher_hotplug_callback(struct notifier_block *nfb,
-                                        unsigned long action, void *hcpu)
+static int bL_switcher_cpu_pre(unsigned int cpu)
 {
-        if (bL_switcher_active) {
-                int pairing = bL_switcher_cpu_pairing[(unsigned long)hcpu];
-                switch (action & 0xf) {
-                case CPU_UP_PREPARE:
-                case CPU_DOWN_PREPARE:
-                        if (pairing == -1)
-                                return NOTIFY_BAD;
-                }
-        }
-        return NOTIFY_DONE;
+        int pairing;
+
+        if (!bL_switcher_active)
+                return 0;
+
+        pairing = bL_switcher_cpu_pairing[cpu];
+
+        if (pairing == -1)
+                return -EINVAL;
+        return 0;
 }
 
 static bool no_bL_switcher;
@@ -782,8 +781,15 @@ static int __init bL_switcher_init(void)
         if (!mcpm_is_available())
                 return -ENODEV;
 
-        cpu_notifier(bL_switcher_hotplug_callback, 0);
-
+        cpuhp_setup_state_nocalls(CPUHP_ARM_BL_PREPARE, "arm/bl:prepare",
+                                  bL_switcher_cpu_pre, NULL);
+        ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "arm/bl:predown",
+                                        NULL, bL_switcher_cpu_pre);
+        if (ret < 0) {
+                cpuhp_remove_state_nocalls(CPUHP_ARM_BL_PREPARE);
+                pr_err("bL_switcher: Failed to allocate a hotplug state\n");
+                return ret;
+        }
         if (!no_bL_switcher) {
                 ret = bL_switcher_enable();
                 if (ret)
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 12bbcf3ded70..e3771fb959c0 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -61,6 +61,7 @@ enum cpuhp_state {
         CPUHP_NET_FLOW_PREPARE,
         CPUHP_TOPOLOGY_PREPARE,
         CPUHP_NET_IUCV_PREPARE,
+        CPUHP_ARM_BL_PREPARE,
         CPUHP_TIMERS_DEAD,
         CPUHP_NOTF_ERR_INJ_PREPARE,
         CPUHP_MIPS_SOC_PREPARE,