[deliverable/linux.git] / drivers / mfd / vexpress-config.c

/*
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * Copyright (C) 2012 ARM Limited
 */

#define pr_fmt(fmt) "vexpress-config: " fmt

#include <linux/bitops.h>
#include <linux/completion.h>
#include <linux/export.h>
#include <linux/list.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/vexpress.h>


#define VEXPRESS_CONFIG_MAX_BRIDGES 2

static struct vexpress_config_bridge {
	struct device_node *node;
	struct vexpress_config_bridge_info *info;
	struct list_head transactions;
	spinlock_t transactions_lock;
} vexpress_config_bridges[VEXPRESS_CONFIG_MAX_BRIDGES];

static DECLARE_BITMAP(vexpress_config_bridges_map,
		ARRAY_SIZE(vexpress_config_bridges));
static DEFINE_MUTEX(vexpress_config_bridges_mutex);

struct vexpress_config_bridge *vexpress_config_bridge_register(
		struct device_node *node,
		struct vexpress_config_bridge_info *info)
{
	struct vexpress_config_bridge *bridge;
	int i;

	pr_debug("Registering bridge '%s'\n", info->name);

	mutex_lock(&vexpress_config_bridges_mutex);
	i = find_first_zero_bit(vexpress_config_bridges_map,
			ARRAY_SIZE(vexpress_config_bridges));
	if (i >= ARRAY_SIZE(vexpress_config_bridges)) {
		pr_err("Can't register more bridges!\n");
		mutex_unlock(&vexpress_config_bridges_mutex);
		return NULL;
	}
	__set_bit(i, vexpress_config_bridges_map);
	bridge = &vexpress_config_bridges[i];

	bridge->node = node;
	bridge->info = info;
	INIT_LIST_HEAD(&bridge->transactions);
	spin_lock_init(&bridge->transactions_lock);

	mutex_unlock(&vexpress_config_bridges_mutex);

	return bridge;
}
EXPORT_SYMBOL(vexpress_config_bridge_register);

void vexpress_config_bridge_unregister(struct vexpress_config_bridge *bridge)
{
	struct vexpress_config_bridge __bridge = *bridge;
	int i;

	mutex_lock(&vexpress_config_bridges_mutex);
	for (i = 0; i < ARRAY_SIZE(vexpress_config_bridges); i++)
		if (&vexpress_config_bridges[i] == bridge)
			__clear_bit(i, vexpress_config_bridges_map);
	mutex_unlock(&vexpress_config_bridges_mutex);

	WARN_ON(!list_empty(&__bridge.transactions));
	while (!list_empty(&__bridge.transactions))
		cpu_relax();
}
EXPORT_SYMBOL(vexpress_config_bridge_unregister);


struct vexpress_config_func {
	struct vexpress_config_bridge *bridge;
	void *func;
};

struct vexpress_config_func *__vexpress_config_func_get(struct device *dev,
		struct device_node *node)
{
	struct device_node *bridge_node;
	struct vexpress_config_func *func;
	int i;

	if (WARN_ON(dev && node && dev->of_node != node))
		return NULL;
	if (dev && !node)
		node = dev->of_node;

	func = kzalloc(sizeof(*func), GFP_KERNEL);
	if (!func)
		return NULL;

	bridge_node = of_node_get(node);
	while (bridge_node) {
		const __be32 *prop = of_get_property(bridge_node,
				"arm,vexpress,config-bridge", NULL);

		if (prop) {
			bridge_node = of_find_node_by_phandle(
					be32_to_cpup(prop));
			break;
		}

		bridge_node = of_get_next_parent(bridge_node);
	}

	mutex_lock(&vexpress_config_bridges_mutex);
	for (i = 0; i < ARRAY_SIZE(vexpress_config_bridges); i++) {
		struct vexpress_config_bridge *bridge =
				&vexpress_config_bridges[i];

		if (test_bit(i, vexpress_config_bridges_map) &&
				bridge->node == bridge_node) {
			func->bridge = bridge;
			func->func = bridge->info->func_get(dev, node);
			break;
		}
	}
	mutex_unlock(&vexpress_config_bridges_mutex);

	if (!func->func) {
		of_node_put(node);
		kfree(func);
		return NULL;
	}

	return func;
}
EXPORT_SYMBOL(__vexpress_config_func_get);

void vexpress_config_func_put(struct vexpress_config_func *func)
{
	func->bridge->info->func_put(func->func);
	of_node_put(func->bridge->node);
	kfree(func);
}
EXPORT_SYMBOL(vexpress_config_func_put);

struct vexpress_config_trans {
	struct vexpress_config_func *func;
	int offset;
	bool write;
	u32 *data;
	int status;
	struct completion completion;
	struct list_head list;
};

static void vexpress_config_dump_trans(const char *what,
		struct vexpress_config_trans *trans)
{
	pr_debug("%s %s trans %p func 0x%p offset %d data 0x%x status %d\n",
			what, trans->write ? "write" : "read", trans,
			trans->func->func, trans->offset,
			trans->data ? *trans->data : 0, trans->status);
}

static int vexpress_config_schedule(struct vexpress_config_trans *trans)
{
	int status;
	struct vexpress_config_bridge *bridge = trans->func->bridge;
	unsigned long flags;

	init_completion(&trans->completion);
	trans->status = -EFAULT;

	spin_lock_irqsave(&bridge->transactions_lock, flags);

	if (list_empty(&bridge->transactions)) {
		vexpress_config_dump_trans("Executing", trans);
		status = bridge->info->func_exec(trans->func->func,
				trans->offset, trans->write, trans->data);
	} else {
		vexpress_config_dump_trans("Queuing", trans);
		status = VEXPRESS_CONFIG_STATUS_WAIT;
	}

	switch (status) {
	case VEXPRESS_CONFIG_STATUS_DONE:
		vexpress_config_dump_trans("Finished", trans);
		trans->status = status;
		break;
	case VEXPRESS_CONFIG_STATUS_WAIT:
		list_add_tail(&trans->list, &bridge->transactions);
		break;
	}

	spin_unlock_irqrestore(&bridge->transactions_lock, flags);

	return status;
}

void vexpress_config_complete(struct vexpress_config_bridge *bridge,
		int status)
{
	struct vexpress_config_trans *trans;
	unsigned long flags;
	const char *message = "Completed";

	spin_lock_irqsave(&bridge->transactions_lock, flags);

	trans = list_first_entry(&bridge->transactions,
			struct vexpress_config_trans, list);
	trans->status = status;

	do {
		vexpress_config_dump_trans(message, trans);
		list_del(&trans->list);
		complete(&trans->completion);

		if (list_empty(&bridge->transactions))
			break;

		trans = list_first_entry(&bridge->transactions,
				struct vexpress_config_trans, list);
		vexpress_config_dump_trans("Executing pending", trans);
		trans->status = bridge->info->func_exec(trans->func->func,
				trans->offset, trans->write, trans->data);
		message = "Finished pending";
	} while (trans->status == VEXPRESS_CONFIG_STATUS_DONE);

	spin_unlock_irqrestore(&bridge->transactions_lock, flags);
}
EXPORT_SYMBOL(vexpress_config_complete);

int vexpress_config_wait(struct vexpress_config_trans *trans)
{
	wait_for_completion(&trans->completion);

	return trans->status;
}
EXPORT_SYMBOL(vexpress_config_wait);

int vexpress_config_read(struct vexpress_config_func *func, int offset,
		u32 *data)
{
	struct vexpress_config_trans trans = {
		.func = func,
		.offset = offset,
		.write = false,
		.data = data,
		.status = 0,
	};
	int status = vexpress_config_schedule(&trans);

	if (status == VEXPRESS_CONFIG_STATUS_WAIT)
		status = vexpress_config_wait(&trans);

	return status;
}
EXPORT_SYMBOL(vexpress_config_read);

int vexpress_config_write(struct vexpress_config_func *func, int offset,
		u32 data)
{
	struct vexpress_config_trans trans = {
		.func = func,
		.offset = offset,
		.write = true,
		.data = &data,
		.status = 0,
	};
	int status = vexpress_config_schedule(&trans);

	if (status == VEXPRESS_CONFIG_STATUS_WAIT)
		status = vexpress_config_wait(&trans);

	return status;
}
EXPORT_SYMBOL(vexpress_config_write);
Commit	Line	Data
3ecbf05b PM	1	/*
	2	* This program is free software; you can redistribute it and/or modify
	3	* it under the terms of the GNU General Public License version 2 as
	4	* published by the Free Software Foundation.
	5	*
	6	* This program is distributed in the hope that it will be useful,
	7	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	8	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	9	* GNU General Public License for more details.
	10	*
	11	* Copyright (C) 2012 ARM Limited
	12	*/
	13
	14	#define pr_fmt(fmt) "vexpress-config: " fmt
	15
	16	#include <linux/bitops.h>
	17	#include <linux/completion.h>
	18	#include <linux/export.h>
3ecbf05b PM	19	#include <linux/list.h>
	20	#include <linux/of.h>
	21	#include <linux/of_device.h>
	22	#include <linux/slab.h>
	23	#include <linux/string.h>
	24	#include <linux/vexpress.h>
	25
	26
	27	#define VEXPRESS_CONFIG_MAX_BRIDGES 2
	28
39296693	29	static struct vexpress_config_bridge {
3ecbf05b PM	30	struct device_node *node;
	31	struct vexpress_config_bridge_info *info;
	32	struct list_head transactions;
	33	spinlock_t transactions_lock;
	34	} vexpress_config_bridges[VEXPRESS_CONFIG_MAX_BRIDGES];
	35
	36	static DECLARE_BITMAP(vexpress_config_bridges_map,
	37	ARRAY_SIZE(vexpress_config_bridges));
	38	static DEFINE_MUTEX(vexpress_config_bridges_mutex);
	39
	40	struct vexpress_config_bridge *vexpress_config_bridge_register(
	41	struct device_node *node,
	42	struct vexpress_config_bridge_info *info)
	43	{
	44	struct vexpress_config_bridge *bridge;
	45	int i;
	46
	47	pr_debug("Registering bridge '%s'\n", info->name);
	48
	49	mutex_lock(&vexpress_config_bridges_mutex);
	50	i = find_first_zero_bit(vexpress_config_bridges_map,
	51	ARRAY_SIZE(vexpress_config_bridges));
	52	if (i >= ARRAY_SIZE(vexpress_config_bridges)) {
	53	pr_err("Can't register more bridges!\n");
	54	mutex_unlock(&vexpress_config_bridges_mutex);
	55	return NULL;
	56	}
	57	__set_bit(i, vexpress_config_bridges_map);
	58	bridge = &vexpress_config_bridges[i];
	59
	60	bridge->node = node;
	61	bridge->info = info;
	62	INIT_LIST_HEAD(&bridge->transactions);
	63	spin_lock_init(&bridge->transactions_lock);
	64
	65	mutex_unlock(&vexpress_config_bridges_mutex);
	66
	67	return bridge;
	68	}
a17155bc	69	EXPORT_SYMBOL(vexpress_config_bridge_register);
3ecbf05b PM	70
	71	void vexpress_config_bridge_unregister(struct vexpress_config_bridge *bridge)
	72	{
	73	struct vexpress_config_bridge __bridge = *bridge;
	74	int i;
	75
	76	mutex_lock(&vexpress_config_bridges_mutex);
	77	for (i = 0; i < ARRAY_SIZE(vexpress_config_bridges); i++)
	78	if (&vexpress_config_bridges[i] == bridge)
	79	__clear_bit(i, vexpress_config_bridges_map);
	80	mutex_unlock(&vexpress_config_bridges_mutex);
	81
	82	WARN_ON(!list_empty(&__bridge.transactions));
	83	while (!list_empty(&__bridge.transactions))
	84	cpu_relax();
	85	}
a17155bc	86	EXPORT_SYMBOL(vexpress_config_bridge_unregister);
3ecbf05b PM	87
	88
	89	struct vexpress_config_func {
	90	struct vexpress_config_bridge *bridge;
	91	void *func;
	92	};
	93
	94	struct vexpress_config_func __vexpress_config_func_get(struct device dev,
	95	struct device_node *node)
	96	{
	97	struct device_node *bridge_node;
	98	struct vexpress_config_func *func;
	99	int i;
	100
	101	if (WARN_ON(dev && node && dev->of_node != node))
	102	return NULL;
	103	if (dev && !node)
	104	node = dev->of_node;
	105
	106	func = kzalloc(sizeof(*func), GFP_KERNEL);
	107	if (!func)
	108	return NULL;
	109
	110	bridge_node = of_node_get(node);
	111	while (bridge_node) {
	112	const __be32 *prop = of_get_property(bridge_node,
	113	"arm,vexpress,config-bridge", NULL);
	114
	115	if (prop) {
	116	bridge_node = of_find_node_by_phandle(
	117	be32_to_cpup(prop));
	118	break;
	119	}
	120
	121	bridge_node = of_get_next_parent(bridge_node);
	122	}
	123
	124	mutex_lock(&vexpress_config_bridges_mutex);
	125	for (i = 0; i < ARRAY_SIZE(vexpress_config_bridges); i++) {
	126	struct vexpress_config_bridge *bridge =
	127	&vexpress_config_bridges[i];
	128
	129	if (test_bit(i, vexpress_config_bridges_map) &&
	130	bridge->node == bridge_node) {
	131	func->bridge = bridge;
	132	func->func = bridge->info->func_get(dev, node);
	133	break;
	134	}
	135	}
	136	mutex_unlock(&vexpress_config_bridges_mutex);
	137
	138	if (!func->func) {
	139	of_node_put(node);
	140	kfree(func);
	141	return NULL;
	142	}
	143
	144	return func;
	145	}
a17155bc	146	EXPORT_SYMBOL(__vexpress_config_func_get);
3ecbf05b PM	147
	148	void vexpress_config_func_put(struct vexpress_config_func *func)
	149	{
	150	func->bridge->info->func_put(func->func);
	151	of_node_put(func->bridge->node);
	152	kfree(func);
	153	}
a17155bc	154	EXPORT_SYMBOL(vexpress_config_func_put);
3ecbf05b PM	155
	156	struct vexpress_config_trans {
	157	struct vexpress_config_func *func;
	158	int offset;
	159	bool write;
	160	u32 *data;
	161	int status;
	162	struct completion completion;
	163	struct list_head list;
	164	};
	165
	166	static void vexpress_config_dump_trans(const char *what,
	167	struct vexpress_config_trans *trans)
	168	{
	169	pr_debug("%s %s trans %p func 0x%p offset %d data 0x%x status %d\n",
	170	what, trans->write ? "write" : "read", trans,
	171	trans->func->func, trans->offset,
	172	trans->data ? *trans->data : 0, trans->status);
	173	}
	174
	175	static int vexpress_config_schedule(struct vexpress_config_trans *trans)
	176	{
	177	int status;
	178	struct vexpress_config_bridge *bridge = trans->func->bridge;
	179	unsigned long flags;
	180
	181	init_completion(&trans->completion);
	182	trans->status = -EFAULT;
	183
	184	spin_lock_irqsave(&bridge->transactions_lock, flags);
	185
367764a4 PM	186	if (list_empty(&bridge->transactions)) {
367764a4 PM	187	vexpress_config_dump_trans("Executing", trans);
3ecbf05b PM	188	status = bridge->info->func_exec(trans->func->func,
3ecbf05b PM	189	trans->offset, trans->write, trans->data);
367764a4 PM	190	} else {
367764a4 PM	191	vexpress_config_dump_trans("Queuing", trans);
3ecbf05b	192	status = VEXPRESS_CONFIG_STATUS_WAIT;
367764a4	193	}
3ecbf05b PM	194
	195	switch (status) {
	196	case VEXPRESS_CONFIG_STATUS_DONE:
	197	vexpress_config_dump_trans("Finished", trans);
	198	trans->status = status;
	199	break;
	200	case VEXPRESS_CONFIG_STATUS_WAIT:
	201	list_add_tail(&trans->list, &bridge->transactions);
	202	break;
	203	}
	204
	205	spin_unlock_irqrestore(&bridge->transactions_lock, flags);
	206
	207	return status;
	208	}
	209
	210	void vexpress_config_complete(struct vexpress_config_bridge *bridge,
	211	int status)
	212	{
	213	struct vexpress_config_trans *trans;
	214	unsigned long flags;
367764a4	215	const char *message = "Completed";
3ecbf05b PM	216
	217	spin_lock_irqsave(&bridge->transactions_lock, flags);
	218
	219	trans = list_first_entry(&bridge->transactions,
	220	struct vexpress_config_trans, list);
3ecbf05b	221	trans->status = status;
3ecbf05b	222
367764a4 PM	223	do {
	224	vexpress_config_dump_trans(message, trans);
	225	list_del(&trans->list);
	226	complete(&trans->completion);
3ecbf05b	227
367764a4 PM	228	if (list_empty(&bridge->transactions))
	229	break;
	230
	231	trans = list_first_entry(&bridge->transactions,
	232	struct vexpress_config_trans, list);
	233	vexpress_config_dump_trans("Executing pending", trans);
	234	trans->status = bridge->info->func_exec(trans->func->func,
	235	trans->offset, trans->write, trans->data);
	236	message = "Finished pending";
	237	} while (trans->status == VEXPRESS_CONFIG_STATUS_DONE);
3ecbf05b	238
367764a4	239	spin_unlock_irqrestore(&bridge->transactions_lock, flags);
3ecbf05b	240	}
a17155bc	241	EXPORT_SYMBOL(vexpress_config_complete);
3ecbf05b PM	242
	243	int vexpress_config_wait(struct vexpress_config_trans *trans)
	244	{
	245	wait_for_completion(&trans->completion);
	246
	247	return trans->status;
	248	}
a17155bc	249	EXPORT_SYMBOL(vexpress_config_wait);
3ecbf05b PM	250
	251	int vexpress_config_read(struct vexpress_config_func *func, int offset,
	252	u32 *data)
	253	{
	254	struct vexpress_config_trans trans = {
	255	.func = func,
	256	.offset = offset,
	257	.write = false,
	258	.data = data,
	259	.status = 0,
	260	};
	261	int status = vexpress_config_schedule(&trans);
	262
	263	if (status == VEXPRESS_CONFIG_STATUS_WAIT)
	264	status = vexpress_config_wait(&trans);
	265
	266	return status;
	267	}
	268	EXPORT_SYMBOL(vexpress_config_read);
	269
	270	int vexpress_config_write(struct vexpress_config_func *func, int offset,
	271	u32 data)
	272	{
	273	struct vexpress_config_trans trans = {
	274	.func = func,
	275	.offset = offset,
	276	.write = true,
	277	.data = &data,
	278	.status = 0,
	279	};
	280	int status = vexpress_config_schedule(&trans);
	281
	282	if (status == VEXPRESS_CONFIG_STATUS_WAIT)
	283	status = vexpress_config_wait(&trans);
	284
	285	return status;
	286	}
	287	EXPORT_SYMBOL(vexpress_config_write);