[RFC PATCH 1/4] ARM: remove big.LITTLE switcher support
Bartlomiej Zolnierkiewicz
b.zolnierkie at samsung.com
Mon Jun 27 04:26:07 PDT 2016
It seems that in mainline kernel big.LITTLE switcher support
may be usable only on ARM Versatile Express TC2 platform
(but even this platform doesn't enable it in its defconfig).
Remove big.LITTLE switcher support in favor of using HMP.
Cc: Nicolas Pitre <nico at linaro.org>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi at arm.com>
Cc: Dave Martin <dave.martin at linaro.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie at samsung.com>
---
arch/arm/Kconfig | 19 +-
arch/arm/common/Makefile | 2 -
arch/arm/common/bL_switcher.c | 802 ---------------------------------
arch/arm/common/bL_switcher_dummy_if.c | 71 ---
arch/arm/include/asm/bL_switcher.h | 77 ----
5 files changed, 1 insertion(+), 970 deletions(-)
delete mode 100644 arch/arm/common/bL_switcher.c
delete mode 100644 arch/arm/common/bL_switcher_dummy_if.c
delete mode 100644 arch/arm/include/asm/bL_switcher.h
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 397e7f5..8c0f70d6 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1361,23 +1361,6 @@ config BIG_LITTLE
This option enables support selections for the big.LITTLE
system architecture.
-config BL_SWITCHER
- bool "big.LITTLE switcher support"
- depends on BIG_LITTLE && MCPM && HOTPLUG_CPU && ARM_GIC
- select CPU_PM
- help
- The big.LITTLE "switcher" provides the core functionality to
- transparently handle transition between a cluster of A15's
- and a cluster of A7's in a big.LITTLE system.
-
-config BL_SWITCHER_DUMMY_IF
- tristate "Simple big.LITTLE switcher user interface"
- depends on BL_SWITCHER && DEBUG_KERNEL
- help
- This is a simple and dummy char dev interface to control
- the big.LITTLE switcher core code. It is meant for
- debugging purposes only.
-
choice
prompt "Memory split"
depends on MMU
@@ -2137,7 +2120,7 @@ config ARCH_SUSPEND_POSSIBLE
def_bool y
config ARM_CPU_SUSPEND
- def_bool PM_SLEEP || BL_SWITCHER || ARM_PSCI_FW
+ def_bool PM_SLEEP || ARM_PSCI_FW
depends on ARCH_SUSPEND_POSSIBLE
config ARCH_HIBERNATION_POSSIBLE
diff --git a/arch/arm/common/Makefile b/arch/arm/common/Makefile
index 27f23b1..b464a9b 100644
--- a/arch/arm/common/Makefile
+++ b/arch/arm/common/Makefile
@@ -15,5 +15,3 @@ obj-$(CONFIG_MCPM) += mcpm_head.o mcpm_entry.o mcpm_platsmp.o vlock.o
CFLAGS_REMOVE_mcpm_entry.o = -pg
AFLAGS_mcpm_head.o := -march=armv7-a
AFLAGS_vlock.o := -march=armv7-a
-obj-$(CONFIG_BL_SWITCHER) += bL_switcher.o
-obj-$(CONFIG_BL_SWITCHER_DUMMY_IF) += bL_switcher_dummy_if.o
diff --git a/arch/arm/common/bL_switcher.c b/arch/arm/common/bL_switcher.c
deleted file mode 100644
index 37dc0fe..0000000
--- a/arch/arm/common/bL_switcher.c
+++ /dev/null
@@ -1,802 +0,0 @@
-/*
- * arch/arm/common/bL_switcher.c -- big.LITTLE cluster switcher core driver
- *
- * Created by: Nicolas Pitre, March 2012
- * Copyright: (C) 2012-2013 Linaro Limited
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
-
-#include <linux/atomic.h>
-#include <linux/init.h>
-#include <linux/kernel.h>
-#include <linux/module.h>
-#include <linux/sched.h>
-#include <linux/interrupt.h>
-#include <linux/cpu_pm.h>
-#include <linux/cpu.h>
-#include <linux/cpumask.h>
-#include <linux/kthread.h>
-#include <linux/wait.h>
-#include <linux/time.h>
-#include <linux/clockchips.h>
-#include <linux/hrtimer.h>
-#include <linux/tick.h>
-#include <linux/notifier.h>
-#include <linux/mm.h>
-#include <linux/mutex.h>
-#include <linux/smp.h>
-#include <linux/spinlock.h>
-#include <linux/string.h>
-#include <linux/sysfs.h>
-#include <linux/irqchip/arm-gic.h>
-#include <linux/moduleparam.h>
-
-#include <asm/smp_plat.h>
-#include <asm/cputype.h>
-#include <asm/suspend.h>
-#include <asm/mcpm.h>
-#include <asm/bL_switcher.h>
-
-#define CREATE_TRACE_POINTS
-#include <trace/events/power_cpu_migrate.h>
-
-
-/*
- * Use our own MPIDR accessors as the generic ones in asm/cputype.h have
- * __attribute_const__ and we don't want the compiler to assume any
- * constness here as the value _does_ change along some code paths.
- */
-
-static int read_mpidr(void)
-{
- unsigned int id;
- asm volatile ("mrc p15, 0, %0, c0, c0, 5" : "=r" (id));
- return id & MPIDR_HWID_BITMASK;
-}
-
-/*
- * bL switcher core code.
- */
-
-static void bL_do_switch(void *_arg)
-{
- unsigned ib_mpidr, ib_cpu, ib_cluster;
- long volatile handshake, **handshake_ptr = _arg;
-
- pr_debug("%s\n", __func__);
-
- ib_mpidr = cpu_logical_map(smp_processor_id());
- ib_cpu = MPIDR_AFFINITY_LEVEL(ib_mpidr, 0);
- ib_cluster = MPIDR_AFFINITY_LEVEL(ib_mpidr, 1);
-
- /* Advertise our handshake location */
- if (handshake_ptr) {
- handshake = 0;
- *handshake_ptr = &handshake;
- } else
- handshake = -1;
-
- /*
- * Our state has been saved at this point. Let's release our
- * inbound CPU.
- */
- mcpm_set_entry_vector(ib_cpu, ib_cluster, cpu_resume);
- sev();
-
- /*
- * From this point, we must assume that our counterpart CPU might
- * have taken over in its parallel world already, as if execution
- * just returned from cpu_suspend(). It is therefore important to
- * be very careful not to make any change the other guy is not
- * expecting. This is why we need stack isolation.
- *
- * Fancy under cover tasks could be performed here. For now
- * we have none.
- */
-
- /*
- * Let's wait until our inbound is alive.
- */
- while (!handshake) {
- wfe();
- smp_mb();
- }
-
- /* Let's put ourself down. */
- mcpm_cpu_power_down();
-
- /* should never get here */
- BUG();
-}
-
-/*
- * Stack isolation. To ensure 'current' remains valid, we just use another
- * piece of our thread's stack space which should be fairly lightly used.
- * The selected area starts just above the thread_info structure located
- * at the very bottom of the stack, aligned to a cache line, and indexed
- * with the cluster number.
- */
-#define STACK_SIZE 512
-extern void call_with_stack(void (*fn)(void *), void *arg, void *sp);
-static int bL_switchpoint(unsigned long _arg)
-{
- unsigned int mpidr = read_mpidr();
- unsigned int clusterid = MPIDR_AFFINITY_LEVEL(mpidr, 1);
- void *stack = current_thread_info() + 1;
- stack = PTR_ALIGN(stack, L1_CACHE_BYTES);
- stack += clusterid * STACK_SIZE + STACK_SIZE;
- call_with_stack(bL_do_switch, (void *)_arg, stack);
- BUG();
-}
-
-/*
- * Generic switcher interface
- */
-
-static unsigned int bL_gic_id[MAX_CPUS_PER_CLUSTER][MAX_NR_CLUSTERS];
-static int bL_switcher_cpu_pairing[NR_CPUS];
-
-/*
- * bL_switch_to - Switch to a specific cluster for the current CPU
- * @new_cluster_id: the ID of the cluster to switch to.
- *
- * This function must be called on the CPU to be switched.
- * Returns 0 on success, else a negative status code.
- */
-static int bL_switch_to(unsigned int new_cluster_id)
-{
- unsigned int mpidr, this_cpu, that_cpu;
- unsigned int ob_mpidr, ob_cpu, ob_cluster, ib_mpidr, ib_cpu, ib_cluster;
- struct completion inbound_alive;
- long volatile *handshake_ptr;
- int ipi_nr, ret;
-
- this_cpu = smp_processor_id();
- ob_mpidr = read_mpidr();
- ob_cpu = MPIDR_AFFINITY_LEVEL(ob_mpidr, 0);
- ob_cluster = MPIDR_AFFINITY_LEVEL(ob_mpidr, 1);
- BUG_ON(cpu_logical_map(this_cpu) != ob_mpidr);
-
- if (new_cluster_id == ob_cluster)
- return 0;
-
- that_cpu = bL_switcher_cpu_pairing[this_cpu];
- ib_mpidr = cpu_logical_map(that_cpu);
- ib_cpu = MPIDR_AFFINITY_LEVEL(ib_mpidr, 0);
- ib_cluster = MPIDR_AFFINITY_LEVEL(ib_mpidr, 1);
-
- pr_debug("before switch: CPU %d MPIDR %#x -> %#x\n",
- this_cpu, ob_mpidr, ib_mpidr);
-
- this_cpu = smp_processor_id();
-
- /* Close the gate for our entry vectors */
- mcpm_set_entry_vector(ob_cpu, ob_cluster, NULL);
- mcpm_set_entry_vector(ib_cpu, ib_cluster, NULL);
-
- /* Install our "inbound alive" notifier. */
- init_completion(&inbound_alive);
- ipi_nr = register_ipi_completion(&inbound_alive, this_cpu);
- ipi_nr |= ((1 << 16) << bL_gic_id[ob_cpu][ob_cluster]);
- mcpm_set_early_poke(ib_cpu, ib_cluster, gic_get_sgir_physaddr(), ipi_nr);
-
- /*
- * Let's wake up the inbound CPU now in case it requires some delay
- * to come online, but leave it gated in our entry vector code.
- */
- ret = mcpm_cpu_power_up(ib_cpu, ib_cluster);
- if (ret) {
- pr_err("%s: mcpm_cpu_power_up() returned %d\n", __func__, ret);
- return ret;
- }
-
- /*
- * Raise a SGI on the inbound CPU to make sure it doesn't stall
- * in a possible WFI, such as in bL_power_down().
- */
- gic_send_sgi(bL_gic_id[ib_cpu][ib_cluster], 0);
-
- /*
- * Wait for the inbound to come up. This allows for other
- * tasks to be scheduled in the mean time.
- */
- wait_for_completion(&inbound_alive);
- mcpm_set_early_poke(ib_cpu, ib_cluster, 0, 0);
-
- /*
- * From this point we are entering the switch critical zone
- * and can't take any interrupts anymore.
- */
- local_irq_disable();
- local_fiq_disable();
- trace_cpu_migrate_begin(ktime_get_real_ns(), ob_mpidr);
-
- /* redirect GIC's SGIs to our counterpart */
- gic_migrate_target(bL_gic_id[ib_cpu][ib_cluster]);
-
- tick_suspend_local();
-
- ret = cpu_pm_enter();
-
- /* we can not tolerate errors at this point */
- if (ret)
- panic("%s: cpu_pm_enter() returned %d\n", __func__, ret);
-
- /* Swap the physical CPUs in the logical map for this logical CPU. */
- cpu_logical_map(this_cpu) = ib_mpidr;
- cpu_logical_map(that_cpu) = ob_mpidr;
-
- /* Let's do the actual CPU switch. */
- ret = cpu_suspend((unsigned long)&handshake_ptr, bL_switchpoint);
- if (ret > 0)
- panic("%s: cpu_suspend() returned %d\n", __func__, ret);
-
- /* We are executing on the inbound CPU at this point */
- mpidr = read_mpidr();
- pr_debug("after switch: CPU %d MPIDR %#x\n", this_cpu, mpidr);
- BUG_ON(mpidr != ib_mpidr);
-
- mcpm_cpu_powered_up();
-
- ret = cpu_pm_exit();
-
- tick_resume_local();
-
- trace_cpu_migrate_finish(ktime_get_real_ns(), ib_mpidr);
- local_fiq_enable();
- local_irq_enable();
-
- *handshake_ptr = 1;
- dsb_sev();
-
- if (ret)
- pr_err("%s exiting with error %d\n", __func__, ret);
- return ret;
-}
-
-struct bL_thread {
- spinlock_t lock;
- struct task_struct *task;
- wait_queue_head_t wq;
- int wanted_cluster;
- struct completion started;
- bL_switch_completion_handler completer;
- void *completer_cookie;
-};
-
-static struct bL_thread bL_threads[NR_CPUS];
-
-static int bL_switcher_thread(void *arg)
-{
- struct bL_thread *t = arg;
- struct sched_param param = { .sched_priority = 1 };
- int cluster;
- bL_switch_completion_handler completer;
- void *completer_cookie;
-
- sched_setscheduler_nocheck(current, SCHED_FIFO, ¶m);
- complete(&t->started);
-
- do {
- if (signal_pending(current))
- flush_signals(current);
- wait_event_interruptible(t->wq,
- t->wanted_cluster != -1 ||
- kthread_should_stop());
-
- spin_lock(&t->lock);
- cluster = t->wanted_cluster;
- completer = t->completer;
- completer_cookie = t->completer_cookie;
- t->wanted_cluster = -1;
- t->completer = NULL;
- spin_unlock(&t->lock);
-
- if (cluster != -1) {
- bL_switch_to(cluster);
-
- if (completer)
- completer(completer_cookie);
- }
- } while (!kthread_should_stop());
-
- return 0;
-}
-
-static struct task_struct *bL_switcher_thread_create(int cpu, void *arg)
-{
- struct task_struct *task;
-
- task = kthread_create_on_node(bL_switcher_thread, arg,
- cpu_to_node(cpu), "kswitcher_%d", cpu);
- if (!IS_ERR(task)) {
- kthread_bind(task, cpu);
- wake_up_process(task);
- } else
- pr_err("%s failed for CPU %d\n", __func__, cpu);
- return task;
-}
-
-/*
- * bL_switch_request_cb - Switch to a specific cluster for the given CPU,
- * with completion notification via a callback
- *
- * @cpu: the CPU to switch
- * @new_cluster_id: the ID of the cluster to switch to.
- * @completer: switch completion callback. if non-NULL,
- * @completer(@completer_cookie) will be called on completion of
- * the switch, in non-atomic context.
- * @completer_cookie: opaque context argument for @completer.
- *
- * This function causes a cluster switch on the given CPU by waking up
- * the appropriate switcher thread. This function may or may not return
- * before the switch has occurred.
- *
- * If a @completer callback function is supplied, it will be called when
- * the switch is complete. This can be used to determine asynchronously
- * when the switch is complete, regardless of when bL_switch_request()
- * returns. When @completer is supplied, no new switch request is permitted
- * for the affected CPU until after the switch is complete, and @completer
- * has returned.
- */
-int bL_switch_request_cb(unsigned int cpu, unsigned int new_cluster_id,
- bL_switch_completion_handler completer,
- void *completer_cookie)
-{
- struct bL_thread *t;
-
- if (cpu >= ARRAY_SIZE(bL_threads)) {
- pr_err("%s: cpu %d out of bounds\n", __func__, cpu);
- return -EINVAL;
- }
-
- t = &bL_threads[cpu];
-
- if (IS_ERR(t->task))
- return PTR_ERR(t->task);
- if (!t->task)
- return -ESRCH;
-
- spin_lock(&t->lock);
- if (t->completer) {
- spin_unlock(&t->lock);
- return -EBUSY;
- }
- t->completer = completer;
- t->completer_cookie = completer_cookie;
- t->wanted_cluster = new_cluster_id;
- spin_unlock(&t->lock);
- wake_up(&t->wq);
- return 0;
-}
-EXPORT_SYMBOL_GPL(bL_switch_request_cb);
-
-/*
- * Activation and configuration code.
- */
-
-static DEFINE_MUTEX(bL_switcher_activation_lock);
-static BLOCKING_NOTIFIER_HEAD(bL_activation_notifier);
-static unsigned int bL_switcher_active;
-static unsigned int bL_switcher_cpu_original_cluster[NR_CPUS];
-static cpumask_t bL_switcher_removed_logical_cpus;
-
-int bL_switcher_register_notifier(struct notifier_block *nb)
-{
- return blocking_notifier_chain_register(&bL_activation_notifier, nb);
-}
-EXPORT_SYMBOL_GPL(bL_switcher_register_notifier);
-
-int bL_switcher_unregister_notifier(struct notifier_block *nb)
-{
- return blocking_notifier_chain_unregister(&bL_activation_notifier, nb);
-}
-EXPORT_SYMBOL_GPL(bL_switcher_unregister_notifier);
-
-static int bL_activation_notify(unsigned long val)
-{
- int ret;
-
- ret = blocking_notifier_call_chain(&bL_activation_notifier, val, NULL);
- if (ret & NOTIFY_STOP_MASK)
- pr_err("%s: notifier chain failed with status 0x%x\n",
- __func__, ret);
- return notifier_to_errno(ret);
-}
-
-static void bL_switcher_restore_cpus(void)
-{
- int 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)
-{
- int i, j, cluster_0, gic_id, ret;
- unsigned int cpu, cluster, mask;
- cpumask_t available_cpus;
-
- /* First pass to validate what we have */
- mask = 0;
- for_each_online_cpu(i) {
- cpu = MPIDR_AFFINITY_LEVEL(cpu_logical_map(i), 0);
- cluster = MPIDR_AFFINITY_LEVEL(cpu_logical_map(i), 1);
- if (cluster >= 2) {
- pr_err("%s: only dual cluster systems are supported\n", __func__);
- return -EINVAL;
- }
- if (WARN_ON(cpu >= MAX_CPUS_PER_CLUSTER))
- return -EINVAL;
- mask |= (1 << cluster);
- }
- if (mask != 3) {
- pr_err("%s: no CPU pairing possible\n", __func__);
- return -EINVAL;
- }
-
- /*
- * Now let's do the pairing. We match each CPU with another CPU
- * from a different cluster. To get a uniform scheduling behavior
- * without fiddling with CPU topology and compute capacity data,
- * we'll use logical CPUs initially belonging to the same cluster.
- */
- memset(bL_switcher_cpu_pairing, -1, sizeof(bL_switcher_cpu_pairing));
- cpumask_copy(&available_cpus, cpu_online_mask);
- cluster_0 = -1;
- for_each_cpu(i, &available_cpus) {
- int match = -1;
- cluster = MPIDR_AFFINITY_LEVEL(cpu_logical_map(i), 1);
- if (cluster_0 == -1)
- cluster_0 = cluster;
- if (cluster != cluster_0)
- continue;
- cpumask_clear_cpu(i, &available_cpus);
- for_each_cpu(j, &available_cpus) {
- cluster = MPIDR_AFFINITY_LEVEL(cpu_logical_map(j), 1);
- /*
- * Let's remember the last match to create "odd"
- * pairings on purpose in order for other code not
- * to assume any relation between physical and
- * logical CPU numbers.
- */
- if (cluster != cluster_0)
- match = j;
- }
- if (match != -1) {
- bL_switcher_cpu_pairing[i] = match;
- cpumask_clear_cpu(match, &available_cpus);
- pr_info("CPU%d paired with CPU%d\n", i, match);
- }
- }
-
- /*
- * Now we disable the unwanted CPUs i.e. everything that has no
- * pairing information (that includes the pairing counterparts).
- */
- cpumask_clear(&bL_switcher_removed_logical_cpus);
- for_each_online_cpu(i) {
- cpu = MPIDR_AFFINITY_LEVEL(cpu_logical_map(i), 0);
- cluster = MPIDR_AFFINITY_LEVEL(cpu_logical_map(i), 1);
-
- /* Let's take note of the GIC ID for this CPU */
- gic_id = gic_get_cpu_id(i);
- if (gic_id < 0) {
- pr_err("%s: bad GIC ID for CPU %d\n", __func__, i);
- bL_switcher_restore_cpus();
- return -EINVAL;
- }
- bL_gic_id[cpu][cluster] = gic_id;
- pr_info("GIC ID for CPU %u cluster %u is %u\n",
- cpu, cluster, gic_id);
-
- if (bL_switcher_cpu_pairing[i] != -1) {
- bL_switcher_cpu_original_cluster[i] = cluster;
- continue;
- }
-
- ret = device_offline(get_cpu_device(i));
- if (ret) {
- bL_switcher_restore_cpus();
- return ret;
- }
- cpumask_set_cpu(i, &bL_switcher_removed_logical_cpus);
- }
-
- return 0;
-}
-
-/* Determine the logical CPU a given physical CPU is grouped on. */
-int bL_switcher_get_logical_index(u32 mpidr)
-{
- int cpu;
-
- if (!bL_switcher_active)
- return -EUNATCH;
-
- mpidr &= MPIDR_HWID_BITMASK;
- for_each_online_cpu(cpu) {
- int pairing = bL_switcher_cpu_pairing[cpu];
- if (pairing == -1)
- continue;
- if ((mpidr == cpu_logical_map(cpu)) ||
- (mpidr == cpu_logical_map(pairing)))
- return cpu;
- }
- return -EINVAL;
-}
-
-static void bL_switcher_trace_trigger_cpu(void *__always_unused info)
-{
- trace_cpu_migrate_current(ktime_get_real_ns(), read_mpidr());
-}
-
-int bL_switcher_trace_trigger(void)
-{
- int ret;
-
- preempt_disable();
-
- bL_switcher_trace_trigger_cpu(NULL);
- ret = smp_call_function(bL_switcher_trace_trigger_cpu, NULL, true);
-
- preempt_enable();
-
- return ret;
-}
-EXPORT_SYMBOL_GPL(bL_switcher_trace_trigger);
-
-static int bL_switcher_enable(void)
-{
- int cpu, ret;
-
- mutex_lock(&bL_switcher_activation_lock);
- lock_device_hotplug();
- if (bL_switcher_active) {
- unlock_device_hotplug();
- mutex_unlock(&bL_switcher_activation_lock);
- return 0;
- }
-
- pr_info("big.LITTLE switcher initializing\n");
-
- ret = bL_activation_notify(BL_NOTIFY_PRE_ENABLE);
- if (ret)
- goto error;
-
- ret = bL_switcher_halve_cpus();
- if (ret)
- goto error;
-
- bL_switcher_trace_trigger();
-
- for_each_online_cpu(cpu) {
- struct bL_thread *t = &bL_threads[cpu];
- spin_lock_init(&t->lock);
- init_waitqueue_head(&t->wq);
- init_completion(&t->started);
- t->wanted_cluster = -1;
- t->task = bL_switcher_thread_create(cpu, t);
- }
-
- bL_switcher_active = 1;
- bL_activation_notify(BL_NOTIFY_POST_ENABLE);
- pr_info("big.LITTLE switcher initialized\n");
- goto out;
-
-error:
- pr_warn("big.LITTLE switcher initialization failed\n");
- bL_activation_notify(BL_NOTIFY_POST_DISABLE);
-
-out:
- unlock_device_hotplug();
- mutex_unlock(&bL_switcher_activation_lock);
- return ret;
-}
-
-#ifdef CONFIG_SYSFS
-
-static void bL_switcher_disable(void)
-{
- unsigned int cpu, cluster;
- struct bL_thread *t;
- struct task_struct *task;
-
- mutex_lock(&bL_switcher_activation_lock);
- lock_device_hotplug();
-
- if (!bL_switcher_active)
- goto out;
-
- if (bL_activation_notify(BL_NOTIFY_PRE_DISABLE) != 0) {
- bL_activation_notify(BL_NOTIFY_POST_ENABLE);
- goto out;
- }
-
- bL_switcher_active = 0;
-
- /*
- * To deactivate the switcher, we must shut down the switcher
- * threads to prevent any other requests from being accepted.
- * Then, if the final cluster for given logical CPU is not the
- * same as the original one, we'll recreate a switcher thread
- * just for the purpose of switching the CPU back without any
- * possibility for interference from external requests.
- */
- for_each_online_cpu(cpu) {
- t = &bL_threads[cpu];
- task = t->task;
- t->task = NULL;
- if (!task || IS_ERR(task))
- continue;
- kthread_stop(task);
- /* no more switch may happen on this CPU at this point */
- cluster = MPIDR_AFFINITY_LEVEL(cpu_logical_map(cpu), 1);
- if (cluster == bL_switcher_cpu_original_cluster[cpu])
- continue;
- init_completion(&t->started);
- t->wanted_cluster = bL_switcher_cpu_original_cluster[cpu];
- task = bL_switcher_thread_create(cpu, t);
- if (!IS_ERR(task)) {
- wait_for_completion(&t->started);
- kthread_stop(task);
- cluster = MPIDR_AFFINITY_LEVEL(cpu_logical_map(cpu), 1);
- if (cluster == bL_switcher_cpu_original_cluster[cpu])
- continue;
- }
- /* If execution gets here, we're in trouble. */
- pr_crit("%s: unable to restore original cluster for CPU %d\n",
- __func__, cpu);
- pr_crit("%s: CPU %d can't be restored\n",
- __func__, bL_switcher_cpu_pairing[cpu]);
- cpumask_clear_cpu(bL_switcher_cpu_pairing[cpu],
- &bL_switcher_removed_logical_cpus);
- }
-
- bL_switcher_restore_cpus();
- bL_switcher_trace_trigger();
-
- bL_activation_notify(BL_NOTIFY_POST_DISABLE);
-
-out:
- unlock_device_hotplug();
- mutex_unlock(&bL_switcher_activation_lock);
-}
-
-static ssize_t bL_switcher_active_show(struct kobject *kobj,
- struct kobj_attribute *attr, char *buf)
-{
- return sprintf(buf, "%u\n", bL_switcher_active);
-}
-
-static ssize_t bL_switcher_active_store(struct kobject *kobj,
- struct kobj_attribute *attr, const char *buf, size_t count)
-{
- int ret;
-
- switch (buf[0]) {
- case '0':
- bL_switcher_disable();
- ret = 0;
- break;
- case '1':
- ret = bL_switcher_enable();
- break;
- default:
- ret = -EINVAL;
- }
-
- return (ret >= 0) ? count : ret;
-}
-
-static ssize_t bL_switcher_trace_trigger_store(struct kobject *kobj,
- struct kobj_attribute *attr, const char *buf, size_t count)
-{
- int ret = bL_switcher_trace_trigger();
-
- return ret ? ret : count;
-}
-
-static struct kobj_attribute bL_switcher_active_attr =
- __ATTR(active, 0644, bL_switcher_active_show, bL_switcher_active_store);
-
-static struct kobj_attribute bL_switcher_trace_trigger_attr =
- __ATTR(trace_trigger, 0200, NULL, bL_switcher_trace_trigger_store);
-
-static struct attribute *bL_switcher_attrs[] = {
- &bL_switcher_active_attr.attr,
- &bL_switcher_trace_trigger_attr.attr,
- NULL,
-};
-
-static struct attribute_group bL_switcher_attr_group = {
- .attrs = bL_switcher_attrs,
-};
-
-static struct kobject *bL_switcher_kobj;
-
-static int __init bL_switcher_sysfs_init(void)
-{
- int ret;
-
- bL_switcher_kobj = kobject_create_and_add("bL_switcher", kernel_kobj);
- if (!bL_switcher_kobj)
- return -ENOMEM;
- ret = sysfs_create_group(bL_switcher_kobj, &bL_switcher_attr_group);
- if (ret)
- kobject_put(bL_switcher_kobj);
- return ret;
-}
-
-#endif /* CONFIG_SYSFS */
-
-bool bL_switcher_get_enabled(void)
-{
- mutex_lock(&bL_switcher_activation_lock);
-
- return bL_switcher_active;
-}
-EXPORT_SYMBOL_GPL(bL_switcher_get_enabled);
-
-void bL_switcher_put_enabled(void)
-{
- mutex_unlock(&bL_switcher_activation_lock);
-}
-EXPORT_SYMBOL_GPL(bL_switcher_put_enabled);
-
-/*
- * Veto any CPU hotplug operation on those CPUs we've removed
- * 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)
-{
- 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;
-}
-
-static bool no_bL_switcher;
-core_param(no_bL_switcher, no_bL_switcher, bool, 0644);
-
-static int __init bL_switcher_init(void)
-{
- int ret;
-
- if (!mcpm_is_available())
- return -ENODEV;
-
- cpu_notifier(bL_switcher_hotplug_callback, 0);
-
- if (!no_bL_switcher) {
- ret = bL_switcher_enable();
- if (ret)
- return ret;
- }
-
-#ifdef CONFIG_SYSFS
- ret = bL_switcher_sysfs_init();
- if (ret)
- pr_err("%s: unable to create sysfs entry\n", __func__);
-#endif
-
- return 0;
-}
-
-late_initcall(bL_switcher_init);
diff --git a/arch/arm/common/bL_switcher_dummy_if.c b/arch/arm/common/bL_switcher_dummy_if.c
deleted file mode 100644
index 3f47f12..0000000
--- a/arch/arm/common/bL_switcher_dummy_if.c
+++ /dev/null
@@ -1,71 +0,0 @@
-/*
- * arch/arm/common/bL_switcher_dummy_if.c -- b.L switcher dummy interface
- *
- * Created by: Nicolas Pitre, November 2012
- * Copyright: (C) 2012-2013 Linaro Limited
- *
- * Dummy interface to user space for debugging purpose only.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
-
-#include <linux/init.h>
-#include <linux/module.h>
-#include <linux/fs.h>
-#include <linux/miscdevice.h>
-#include <asm/uaccess.h>
-#include <asm/bL_switcher.h>
-
-static ssize_t bL_switcher_write(struct file *file, const char __user *buf,
- size_t len, loff_t *pos)
-{
- unsigned char val[3];
- unsigned int cpu, cluster;
- int ret;
-
- pr_debug("%s\n", __func__);
-
- if (len < 3)
- return -EINVAL;
-
- if (copy_from_user(val, buf, 3))
- return -EFAULT;
-
- /* format: <cpu#>,<cluster#> */
- if (val[0] < '0' || val[0] > '9' ||
- val[1] != ',' ||
- val[2] < '0' || val[2] > '1')
- return -EINVAL;
-
- cpu = val[0] - '0';
- cluster = val[2] - '0';
- ret = bL_switch_request(cpu, cluster);
-
- return ret ? : len;
-}
-
-static const struct file_operations bL_switcher_fops = {
- .write = bL_switcher_write,
- .owner = THIS_MODULE,
-};
-
-static struct miscdevice bL_switcher_device = {
- MISC_DYNAMIC_MINOR,
- "b.L_switcher",
- &bL_switcher_fops
-};
-
-static int __init bL_switcher_dummy_if_init(void)
-{
- return misc_register(&bL_switcher_device);
-}
-
-static void __exit bL_switcher_dummy_if_exit(void)
-{
- misc_deregister(&bL_switcher_device);
-}
-
-module_init(bL_switcher_dummy_if_init);
-module_exit(bL_switcher_dummy_if_exit);
diff --git a/arch/arm/include/asm/bL_switcher.h b/arch/arm/include/asm/bL_switcher.h
deleted file mode 100644
index 1714800..0000000
--- a/arch/arm/include/asm/bL_switcher.h
+++ /dev/null
@@ -1,77 +0,0 @@
-/*
- * arch/arm/include/asm/bL_switcher.h
- *
- * Created by: Nicolas Pitre, April 2012
- * Copyright: (C) 2012-2013 Linaro Limited
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
-
-#ifndef ASM_BL_SWITCHER_H
-#define ASM_BL_SWITCHER_H
-
-#include <linux/compiler.h>
-#include <linux/types.h>
-
-typedef void (*bL_switch_completion_handler)(void *cookie);
-
-int bL_switch_request_cb(unsigned int cpu, unsigned int new_cluster_id,
- bL_switch_completion_handler completer,
- void *completer_cookie);
-static inline int bL_switch_request(unsigned int cpu, unsigned int new_cluster_id)
-{
- return bL_switch_request_cb(cpu, new_cluster_id, NULL, NULL);
-}
-
-/*
- * Register here to be notified about runtime enabling/disabling of
- * the switcher.
- *
- * The notifier chain is called with the switcher activation lock held:
- * the switcher will not be enabled or disabled during callbacks.
- * Callbacks must not call bL_switcher_{get,put}_enabled().
- */
-#define BL_NOTIFY_PRE_ENABLE 0
-#define BL_NOTIFY_POST_ENABLE 1
-#define BL_NOTIFY_PRE_DISABLE 2
-#define BL_NOTIFY_POST_DISABLE 3
-
-#ifdef CONFIG_BL_SWITCHER
-
-int bL_switcher_register_notifier(struct notifier_block *nb);
-int bL_switcher_unregister_notifier(struct notifier_block *nb);
-
-/*
- * Use these functions to temporarily prevent enabling/disabling of
- * the switcher.
- * bL_switcher_get_enabled() returns true if the switcher is currently
- * enabled. Each call to bL_switcher_get_enabled() must be followed
- * by a call to bL_switcher_put_enabled(). These functions are not
- * recursive.
- */
-bool bL_switcher_get_enabled(void);
-void bL_switcher_put_enabled(void);
-
-int bL_switcher_trace_trigger(void);
-int bL_switcher_get_logical_index(u32 mpidr);
-
-#else
-static inline int bL_switcher_register_notifier(struct notifier_block *nb)
-{
- return 0;
-}
-
-static inline int bL_switcher_unregister_notifier(struct notifier_block *nb)
-{
- return 0;
-}
-
-static inline bool bL_switcher_get_enabled(void) { return false; }
-static inline void bL_switcher_put_enabled(void) { }
-static inline int bL_switcher_trace_trigger(void) { return 0; }
-static inline int bL_switcher_get_logical_index(u32 mpidr) { return -EUNATCH; }
-#endif /* CONFIG_BL_SWITCHER */
-
-#endif
--
1.9.1
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