1 // SPDX-License-Identifier: GPL-2.0-only
3  * arch/arm/common/bL_switcher.c -- big.LITTLE cluster switcher core driver
6  * Copyright:	(C) 2012-2013  Linaro Limited
32 #include <linux/irqchip/arm-gic.h>
46  * Use our own MPIDR accessors as the generic ones in asm/cputype.h have
65 	long volatile handshake, **handshake_ptr = _arg;  in bL_do_switch()  local
73 	/* Advertise our handshake location */  in bL_do_switch()
75 		handshake = 0;  in bL_do_switch()
76 		*handshake_ptr = &handshake;  in bL_do_switch()
78 		handshake = -1;  in bL_do_switch()
101 	while (!handshake) {  in bL_do_switch()
114  * Stack isolation.  To ensure 'current' remains valid, we just use another
141  * bL_switch_to - Switch to a specific cluster for the current CPU
169 	pr_debug("before switch: CPU %d MPIDR %#x -> %#x\n",  in bL_switch_to()
278 	complete(&t->started);  in bL_switcher_thread()
283 		wait_event_interruptible(t->wq,  in bL_switcher_thread()
284 				t->wanted_cluster != -1 ||  in bL_switcher_thread()
287 		spin_lock(&t->lock);  in bL_switcher_thread()
288 		cluster = t->wanted_cluster;  in bL_switcher_thread()
289 		completer = t->completer;  in bL_switcher_thread()
290 		completer_cookie = t->completer_cookie;  in bL_switcher_thread()
291 		t->wanted_cluster = -1;  in bL_switcher_thread()
292 		t->completer = NULL;  in bL_switcher_thread()
293 		spin_unlock(&t->lock);  in bL_switcher_thread()
295 		if (cluster != -1) {  in bL_switcher_thread()
321  * bL_switch_request_cb - Switch to a specific cluster for the given CPU,
326  * @completer: switch completion callback.  if non-NULL,
328  *	the switch, in non-atomic context.
350 		return -EINVAL;  in bL_switch_request_cb()
355 	if (IS_ERR(t->task))  in bL_switch_request_cb()
356 		return PTR_ERR(t->task);  in bL_switch_request_cb()
357 	if (!t->task)  in bL_switch_request_cb()
358 		return -ESRCH;  in bL_switch_request_cb()
360 	spin_lock(&t->lock);  in bL_switch_request_cb()
361 	if (t->completer) {  in bL_switch_request_cb()
362 		spin_unlock(&t->lock);  in bL_switch_request_cb()
363 		return -EBUSY;  in bL_switch_request_cb()
365 	t->completer = completer;  in bL_switch_request_cb()
366 	t->completer_cookie = completer_cookie;  in bL_switch_request_cb()
367 	t->wanted_cluster = new_cluster_id;  in bL_switch_request_cb()
368 	spin_unlock(&t->lock);  in bL_switch_request_cb()
369 	wake_up(&t->wq);  in bL_switch_request_cb()
432 			return -EINVAL;  in bL_switcher_halve_cpus()
435 			return -EINVAL;  in bL_switcher_halve_cpus()
440 		return -EINVAL;  in bL_switcher_halve_cpus()
447 	 * we'll use logical CPUs initially belonging to the same cluster.  in bL_switcher_halve_cpus()
449 	memset(bL_switcher_cpu_pairing, -1, sizeof(bL_switcher_cpu_pairing));  in bL_switcher_halve_cpus()
451 	cluster_0 = -1;  in bL_switcher_halve_cpus()
453 		int match = -1;  in bL_switcher_halve_cpus()
455 		if (cluster_0 == -1)  in bL_switcher_halve_cpus()
471 		if (match != -1) {  in bL_switcher_halve_cpus()
492 			return -EINVAL;  in bL_switcher_halve_cpus()
498 		if (bL_switcher_cpu_pairing[i] != -1) {  in bL_switcher_halve_cpus()
520 		return -EUNATCH;  in bL_switcher_get_logical_index()
525 		if (pairing == -1)  in bL_switcher_get_logical_index()
531 	return -EINVAL;  in bL_switcher_get_logical_index()
578 		spin_lock_init(&t->lock);  in bL_switcher_enable()
579 		init_waitqueue_head(&t->wq);  in bL_switcher_enable()
580 		init_completion(&t->started);  in bL_switcher_enable()
581 		t->wanted_cluster = -1;  in bL_switcher_enable()
582 		t->task = bL_switcher_thread_create(cpu, t);  in bL_switcher_enable()
631 		task = t->task;  in bL_switcher_disable()
632 		t->task = NULL;  in bL_switcher_disable()
640 		init_completion(&t->started);  in bL_switcher_disable()
641 		t->wanted_cluster = bL_switcher_cpu_original_cluster[cpu];  in bL_switcher_disable()
644 			wait_for_completion(&t->started);  in bL_switcher_disable()
689 		ret = -EINVAL;  in bL_switcher_active_store()
727 		return -ENOMEM;  in bL_switcher_sysfs_init()
764 	if (pairing == -1)  in bL_switcher_cpu_pre()
765 		return -EINVAL;  in bL_switcher_cpu_pre()
777 		return -ENODEV;  in bL_switcher_init()