Linux-libre 4.2-gnu

1 files changed, 126 insertions, 155 deletions

diff --git a/arch/arm/common/mcpm_entry.c b/arch/arm/common/mcpm_entry.c
index 5f8a52ac7..a923524d1 100644
--- a/arch/arm/common/mcpm_entry.c
+++ b/arch/arm/common/mcpm_entry.c
@@ -20,6 +20,126 @@
 #include <asm/cputype.h>
 #include <asm/suspend.h>
 
+/*
+ * The public API for this code is documented in arch/arm/include/asm/mcpm.h.
+ * For a comprehensive description of the main algorithm used here, please
+ * see Documentation/arm/cluster-pm-race-avoidance.txt.
+ */
+
+struct sync_struct mcpm_sync;
+
+/*
+ * __mcpm_cpu_going_down: Indicates that the cpu is being torn down.
+ *    This must be called at the point of committing to teardown of a CPU.
+ *    The CPU cache (SCTRL.C bit) is expected to still be active.
+ */
+static void __mcpm_cpu_going_down(unsigned int cpu, unsigned int cluster)
+{
+	mcpm_sync.clusters[cluster].cpus[cpu].cpu = CPU_GOING_DOWN;
+	sync_cache_w(&mcpm_sync.clusters[cluster].cpus[cpu].cpu);
+}
+
+/*
+ * __mcpm_cpu_down: Indicates that cpu teardown is complete and that the
+ *    cluster can be torn down without disrupting this CPU.
+ *    To avoid deadlocks, this must be called before a CPU is powered down.
+ *    The CPU cache (SCTRL.C bit) is expected to be off.
+ *    However L2 cache might or might not be active.
+ */
+static void __mcpm_cpu_down(unsigned int cpu, unsigned int cluster)
+{
+	dmb();
+	mcpm_sync.clusters[cluster].cpus[cpu].cpu = CPU_DOWN;
+	sync_cache_w(&mcpm_sync.clusters[cluster].cpus[cpu].cpu);
+	sev();
+}
+
+/*
+ * __mcpm_outbound_leave_critical: Leave the cluster teardown critical section.
+ * @state: the final state of the cluster:
+ *     CLUSTER_UP: no destructive teardown was done and the cluster has been
+ *         restored to the previous state (CPU cache still active); or
+ *     CLUSTER_DOWN: the cluster has been torn-down, ready for power-off
+ *         (CPU cache disabled, L2 cache either enabled or disabled).
+ */
+static void __mcpm_outbound_leave_critical(unsigned int cluster, int state)
+{
+	dmb();
+	mcpm_sync.clusters[cluster].cluster = state;
+	sync_cache_w(&mcpm_sync.clusters[cluster].cluster);
+	sev();
+}
+
+/*
+ * __mcpm_outbound_enter_critical: Enter the cluster teardown critical section.
+ * This function should be called by the last man, after local CPU teardown
+ * is complete.  CPU cache expected to be active.
+ *
+ * Returns:
+ *     false: the critical section was not entered because an inbound CPU was
+ *         observed, or the cluster is already being set up;
+ *     true: the critical section was entered: it is now safe to tear down the
+ *         cluster.
+ */
+static bool __mcpm_outbound_enter_critical(unsigned int cpu, unsigned int cluster)
+{
+	unsigned int i;
+	struct mcpm_sync_struct *c = &mcpm_sync.clusters[cluster];
+
+	/* Warn inbound CPUs that the cluster is being torn down: */
+	c->cluster = CLUSTER_GOING_DOWN;
+	sync_cache_w(&c->cluster);
+
+	/* Back out if the inbound cluster is already in the critical region: */
+	sync_cache_r(&c->inbound);
+	if (c->inbound == INBOUND_COMING_UP)
+		goto abort;
+
+	/*
+	 * Wait for all CPUs to get out of the GOING_DOWN state, so that local
+	 * teardown is complete on each CPU before tearing down the cluster.
+	 *
+	 * If any CPU has been woken up again from the DOWN state, then we
+	 * shouldn't be taking the cluster down at all: abort in that case.
+	 */
+	sync_cache_r(&c->cpus);
+	for (i = 0; i < MAX_CPUS_PER_CLUSTER; i++) {
+		int cpustate;
+
+		if (i == cpu)
+			continue;
+
+		while (1) {
+			cpustate = c->cpus[i].cpu;
+			if (cpustate != CPU_GOING_DOWN)
+				break;
+
+			wfe();
+			sync_cache_r(&c->cpus[i].cpu);
+		}
+
+		switch (cpustate) {
+		case CPU_DOWN:
+			continue;
+
+		default:
+			goto abort;
+		}
+	}
+
+	return true;
+
+abort:
+	__mcpm_outbound_leave_critical(cluster, CLUSTER_UP);
+	return false;
+}
+
+static int __mcpm_cluster_state(unsigned int cluster)
+{
+	sync_cache_r(&mcpm_sync.clusters[cluster].cluster);
+	return mcpm_sync.clusters[cluster].cluster;
+}
+
 extern unsigned long mcpm_entry_vectors[MAX_NR_CLUSTERS][MAX_CPUS_PER_CLUSTER];
 
 void mcpm_set_entry_vector(unsigned cpu, unsigned cluster, void *ptr)
@@ -78,16 +198,11 @@ int mcpm_cpu_power_up(unsigned int cpu, unsigned int cluster)
 	bool cpu_is_down, cluster_is_down;
 	int ret = 0;
 
+	pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
 	if (!platform_ops)
 		return -EUNATCH; /* try not to shadow power_up errors */
 	might_sleep();
 
-	/* backward compatibility callback */
-	if (platform_ops->power_up)
-		return platform_ops->power_up(cpu, cluster);
-
-	pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
-
 	/*
 	 * Since this is called with IRQs enabled, and no arch_spin_lock_irq
 	 * variant exists, we need to disable IRQs manually here.
@@ -128,29 +243,17 @@ void mcpm_cpu_power_down(void)
 	bool cpu_going_down, last_man;
 	phys_reset_t phys_reset;
 
+	mpidr = read_cpuid_mpidr();
+	cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
+	cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
+	pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
 	if (WARN_ON_ONCE(!platform_ops))
 	       return;
 	BUG_ON(!irqs_disabled());
 
-	/*
-	 * Do this before calling into the power_down method,
-	 * as it might not always be safe to do afterwards.
-	 */
 	setup_mm_for_reboot();
 
-	/* backward compatibility callback */
-	if (platform_ops->power_down) {
-		platform_ops->power_down();
-		goto not_dead;
-	}
-
-	mpidr = read_cpuid_mpidr();
-	cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
-	cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
-	pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
-
 	__mcpm_cpu_going_down(cpu, cluster);
-
 	arch_spin_lock(&mcpm_lock);
 	BUG_ON(__mcpm_cluster_state(cluster) != CLUSTER_UP);
 
@@ -187,7 +290,6 @@ void mcpm_cpu_power_down(void)
 	if (cpu_going_down)
 		wfi();
 
-not_dead:
 	/*
 	 * It is possible for a power_up request to happen concurrently
 	 * with a power_down request for the same CPU. In this case the
@@ -219,22 +321,11 @@ int mcpm_wait_for_cpu_powerdown(unsigned int cpu, unsigned int cluster)
 	return ret;
 }
 
-void mcpm_cpu_suspend(u64 expected_residency)
+void mcpm_cpu_suspend(void)
 {
 	if (WARN_ON_ONCE(!platform_ops))
 		return;
 
-	/* backward compatibility callback */
-	if (platform_ops->suspend) {
-		phys_reset_t phys_reset;
-		BUG_ON(!irqs_disabled());
-		setup_mm_for_reboot();
-		platform_ops->suspend(expected_residency);
-		phys_reset = (phys_reset_t)(unsigned long)virt_to_phys(cpu_reset);
-		phys_reset(virt_to_phys(mcpm_entry_point));
-		BUG();
-	}
-
 	/* Some platforms might have to enable special resume modes, etc. */
 	if (platform_ops->cpu_suspend_prepare) {
 		unsigned int mpidr = read_cpuid_mpidr();
@@ -256,12 +347,6 @@ int mcpm_cpu_powered_up(void)
 	if (!platform_ops)
 		return -EUNATCH;
 
-	/* backward compatibility callback */
-	if (platform_ops->powered_up) {
-		platform_ops->powered_up();
-		return 0;
-	}
-
 	mpidr = read_cpuid_mpidr();
 	cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
 	cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
@@ -334,120 +419,6 @@ int __init mcpm_loopback(void (*cache_disable)(void))
 
 #endif
 
-struct sync_struct mcpm_sync;
-
-/*
- * __mcpm_cpu_going_down: Indicates that the cpu is being torn down.
- *    This must be called at the point of committing to teardown of a CPU.
- *    The CPU cache (SCTRL.C bit) is expected to still be active.
- */
-void __mcpm_cpu_going_down(unsigned int cpu, unsigned int cluster)
-{
-	mcpm_sync.clusters[cluster].cpus[cpu].cpu = CPU_GOING_DOWN;
-	sync_cache_w(&mcpm_sync.clusters[cluster].cpus[cpu].cpu);
-}
-
-/*
- * __mcpm_cpu_down: Indicates that cpu teardown is complete and that the
- *    cluster can be torn down without disrupting this CPU.
- *    To avoid deadlocks, this must be called before a CPU is powered down.
- *    The CPU cache (SCTRL.C bit) is expected to be off.
- *    However L2 cache might or might not be active.
- */
-void __mcpm_cpu_down(unsigned int cpu, unsigned int cluster)
-{
-	dmb();
-	mcpm_sync.clusters[cluster].cpus[cpu].cpu = CPU_DOWN;
-	sync_cache_w(&mcpm_sync.clusters[cluster].cpus[cpu].cpu);
-	sev();
-}
-
-/*
- * __mcpm_outbound_leave_critical: Leave the cluster teardown critical section.
- * @state: the final state of the cluster:
- *     CLUSTER_UP: no destructive teardown was done and the cluster has been
- *         restored to the previous state (CPU cache still active); or
- *     CLUSTER_DOWN: the cluster has been torn-down, ready for power-off
- *         (CPU cache disabled, L2 cache either enabled or disabled).
- */
-void __mcpm_outbound_leave_critical(unsigned int cluster, int state)
-{
-	dmb();
-	mcpm_sync.clusters[cluster].cluster = state;
-	sync_cache_w(&mcpm_sync.clusters[cluster].cluster);
-	sev();
-}
-
-/*
- * __mcpm_outbound_enter_critical: Enter the cluster teardown critical section.
- * This function should be called by the last man, after local CPU teardown
- * is complete.  CPU cache expected to be active.
- *
- * Returns:
- *     false: the critical section was not entered because an inbound CPU was
- *         observed, or the cluster is already being set up;
- *     true: the critical section was entered: it is now safe to tear down the
- *         cluster.
- */
-bool __mcpm_outbound_enter_critical(unsigned int cpu, unsigned int cluster)
-{
-	unsigned int i;
-	struct mcpm_sync_struct *c = &mcpm_sync.clusters[cluster];
-
-	/* Warn inbound CPUs that the cluster is being torn down: */
-	c->cluster = CLUSTER_GOING_DOWN;
-	sync_cache_w(&c->cluster);
-
-	/* Back out if the inbound cluster is already in the critical region: */
-	sync_cache_r(&c->inbound);
-	if (c->inbound == INBOUND_COMING_UP)
-		goto abort;
-
-	/*
-	 * Wait for all CPUs to get out of the GOING_DOWN state, so that local
-	 * teardown is complete on each CPU before tearing down the cluster.
-	 *
-	 * If any CPU has been woken up again from the DOWN state, then we
-	 * shouldn't be taking the cluster down at all: abort in that case.
-	 */
-	sync_cache_r(&c->cpus);
-	for (i = 0; i < MAX_CPUS_PER_CLUSTER; i++) {
-		int cpustate;
-
-		if (i == cpu)
-			continue;
-
-		while (1) {
-			cpustate = c->cpus[i].cpu;
-			if (cpustate != CPU_GOING_DOWN)
-				break;
-
-			wfe();
-			sync_cache_r(&c->cpus[i].cpu);
-		}
-
-		switch (cpustate) {
-		case CPU_DOWN:
-			continue;
-
-		default:
-			goto abort;
-		}
-	}
-
-	return true;
-
-abort:
-	__mcpm_outbound_leave_critical(cluster, CLUSTER_UP);
-	return false;
-}
-
-int __mcpm_cluster_state(unsigned int cluster)
-{
-	sync_cache_r(&mcpm_sync.clusters[cluster].cluster);
-	return mcpm_sync.clusters[cluster].cluster;
-}
-
 extern unsigned long mcpm_power_up_setup_phys;
 
 int __init mcpm_sync_init(