[deliverable/linux.git] / net / caif / cfmuxl.c

/*
 * Copyright (C) ST-Ericsson AB 2010
 * Author:	Sjur Brendeland/sjur.brandeland@stericsson.com
 * License terms: GNU General Public License (GPL) version 2
 */

#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__

#include <linux/stddef.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/rculist.h>
#include <net/caif/cfpkt.h>
#include <net/caif/cfmuxl.h>
#include <net/caif/cfsrvl.h>
#include <net/caif/cffrml.h>

#define container_obj(layr) container_of(layr, struct cfmuxl, layer)

#define CAIF_CTRL_CHANNEL 0
#define UP_CACHE_SIZE 8
#define DN_CACHE_SIZE 8

struct cfmuxl {
	struct cflayer layer;
	struct list_head srvl_list;
	struct list_head frml_list;
	struct cflayer *up_cache[UP_CACHE_SIZE];
	struct cflayer *dn_cache[DN_CACHE_SIZE];
	/*
	 * Set when inserting or removing downwards layers.
	 */
	spinlock_t transmit_lock;

	/*
	 * Set when inserting or removing upwards layers.
	 */
	spinlock_t receive_lock;

};

static int cfmuxl_receive(struct cflayer *layr, struct cfpkt *pkt);
static int cfmuxl_transmit(struct cflayer *layr, struct cfpkt *pkt);
static void cfmuxl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
				int phyid);
static struct cflayer *get_up(struct cfmuxl *muxl, u16 id);

struct cflayer *cfmuxl_create(void)
{
	struct cfmuxl *this = kmalloc(sizeof(struct cfmuxl), GFP_ATOMIC);
	if (!this)
		return NULL;
	memset(this, 0, sizeof(*this));
	this->layer.receive = cfmuxl_receive;
	this->layer.transmit = cfmuxl_transmit;
	this->layer.ctrlcmd = cfmuxl_ctrlcmd;
	INIT_LIST_HEAD(&this->srvl_list);
	INIT_LIST_HEAD(&this->frml_list);
	spin_lock_init(&this->transmit_lock);
	spin_lock_init(&this->receive_lock);
	snprintf(this->layer.name, CAIF_LAYER_NAME_SZ, "mux");
	return &this->layer;
}

int cfmuxl_set_uplayer(struct cflayer *layr, struct cflayer *up, u8 linkid)
{
	struct cfmuxl *muxl = container_obj(layr);

	spin_lock_bh(&muxl->receive_lock);
	list_add_rcu(&up->node, &muxl->srvl_list);
	spin_unlock_bh(&muxl->receive_lock);
	return 0;
}

int cfmuxl_set_dnlayer(struct cflayer *layr, struct cflayer *dn, u8 phyid)
{
	struct cfmuxl *muxl = (struct cfmuxl *) layr;

	spin_lock_bh(&muxl->transmit_lock);
	list_add_rcu(&dn->node, &muxl->frml_list);
	spin_unlock_bh(&muxl->transmit_lock);
	return 0;
}

static struct cflayer *get_from_id(struct list_head *list, u16 id)
{
	struct cflayer *lyr;
	list_for_each_entry_rcu(lyr, list, node) {
		if (lyr->id == id)
			return lyr;
	}

	return NULL;
}

struct cflayer *cfmuxl_remove_dnlayer(struct cflayer *layr, u8 phyid)
{
	struct cfmuxl *muxl = container_obj(layr);
	struct cflayer *dn;
	int idx = phyid % DN_CACHE_SIZE;

	spin_lock_bh(&muxl->transmit_lock);
	rcu_assign_pointer(muxl->dn_cache[idx], NULL);
	dn = get_from_id(&muxl->frml_list, phyid);
	if (dn == NULL)
		goto out;

	list_del_rcu(&dn->node);
	caif_assert(dn != NULL);
out:
	spin_unlock_bh(&muxl->transmit_lock);
	return dn;
}

static struct cflayer *get_up(struct cfmuxl *muxl, u16 id)
{
	struct cflayer *up;
	int idx = id % UP_CACHE_SIZE;
	up = rcu_dereference(muxl->up_cache[idx]);
	if (up == NULL || up->id != id) {
		spin_lock_bh(&muxl->receive_lock);
		up = get_from_id(&muxl->srvl_list, id);
		rcu_assign_pointer(muxl->up_cache[idx], up);
		spin_unlock_bh(&muxl->receive_lock);
	}
	return up;
}

static struct cflayer *get_dn(struct cfmuxl *muxl, struct dev_info *dev_info)
{
	struct cflayer *dn;
	int idx = dev_info->id % DN_CACHE_SIZE;
	dn = rcu_dereference(muxl->dn_cache[idx]);
	if (dn == NULL || dn->id != dev_info->id) {
		spin_lock_bh(&muxl->transmit_lock);
		dn = get_from_id(&muxl->frml_list, dev_info->id);
		rcu_assign_pointer(muxl->dn_cache[idx], dn);
		spin_unlock_bh(&muxl->transmit_lock);
	}
	return dn;
}

struct cflayer *cfmuxl_remove_uplayer(struct cflayer *layr, u8 id)
{
	struct cflayer *up;
	struct cfmuxl *muxl = container_obj(layr);
	int idx = id % UP_CACHE_SIZE;

	spin_lock_bh(&muxl->receive_lock);
	up = get_from_id(&muxl->srvl_list, id);
	if (up == NULL)
		goto out;

	rcu_assign_pointer(muxl->up_cache[idx], NULL);
	list_del_rcu(&up->node);
out:
	spin_unlock_bh(&muxl->receive_lock);
	return up;
}

static int cfmuxl_receive(struct cflayer *layr, struct cfpkt *pkt)
{
	int ret;
	struct cfmuxl *muxl = container_obj(layr);
	u8 id;
	struct cflayer *up;
	if (cfpkt_extr_head(pkt, &id, 1) < 0) {
		pr_err("erroneous Caif Packet\n");
		cfpkt_destroy(pkt);
		return -EPROTO;
	}
	rcu_read_lock();
	up = get_up(muxl, id);

	if (up == NULL) {
		pr_debug("Received data on unknown link ID = %d (0x%x)"
			" up == NULL", id, id);
		cfpkt_destroy(pkt);
		/*
		 * Don't return ERROR, since modem misbehaves and sends out
		 * flow on before linksetup response.
		 */

		rcu_read_unlock();
		return /* CFGLU_EPROT; */ 0;
	}

	/* We can't hold rcu_lock during receive, so take a ref count instead */
	cfsrvl_get(up);
	rcu_read_unlock();

	ret = up->receive(up, pkt);

	cfsrvl_put(up);
	return ret;
}

static int cfmuxl_transmit(struct cflayer *layr, struct cfpkt *pkt)
{
	struct cfmuxl *muxl = container_obj(layr);
	int err;
	u8 linkid;
	struct cflayer *dn;
	struct caif_payload_info *info = cfpkt_info(pkt);
	BUG_ON(!info);

	rcu_read_lock();

	dn = get_dn(muxl, info->dev_info);
	if (dn == NULL) {
		pr_debug("Send data on unknown phy ID = %d (0x%x)\n",
			info->dev_info->id, info->dev_info->id);
		rcu_read_unlock();
		cfpkt_destroy(pkt);
		return -ENOTCONN;
	}

	info->hdr_len += 1;
	linkid = info->channel_id;
	cfpkt_add_head(pkt, &linkid, 1);

	/* We can't hold rcu_lock during receive, so take a ref count instead */
	cffrml_hold(dn);

	rcu_read_unlock();

	err = dn->transmit(dn, pkt);

	cffrml_put(dn);
	return err;
}

static void cfmuxl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
				int phyid)
{
	struct cfmuxl *muxl = container_obj(layr);
	struct cflayer *layer;

	rcu_read_lock();
	list_for_each_entry_rcu(layer, &muxl->srvl_list, node) {
		if (cfsrvl_phyid_match(layer, phyid) && layer->ctrlcmd)
			/* NOTE: ctrlcmd is not allowed to block */
			layer->ctrlcmd(layer, ctrl, phyid);
	}
	rcu_read_unlock();
}
Commit	Line	Data
b482cd20 SB	1	/*
	2	* Copyright (C) ST-Ericsson AB 2010
	3	* Author: Sjur Brendeland/sjur.brandeland@stericsson.com
	4	* License terms: GNU General Public License (GPL) version 2
	5	*/
b31fa5ba JP	6
	7	#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
	8
b482cd20 SB	9	#include <linux/stddef.h>
	10	#include <linux/spinlock.h>
	11	#include <linux/slab.h>
0b1e9738	12	#include <linux/rculist.h>
b482cd20 SB	13	#include <net/caif/cfpkt.h>
	14	#include <net/caif/cfmuxl.h>
	15	#include <net/caif/cfsrvl.h>
	16	#include <net/caif/cffrml.h>
	17
	18	#define container_obj(layr) container_of(layr, struct cfmuxl, layer)
	19
	20	#define CAIF_CTRL_CHANNEL 0
	21	#define UP_CACHE_SIZE 8
	22	#define DN_CACHE_SIZE 8
	23
	24	struct cfmuxl {
	25	struct cflayer layer;
	26	struct list_head srvl_list;
	27	struct list_head frml_list;
	28	struct cflayer *up_cache[UP_CACHE_SIZE];
	29	struct cflayer *dn_cache[DN_CACHE_SIZE];
	30	/*
	31	* Set when inserting or removing downwards layers.
	32	*/
	33	spinlock_t transmit_lock;
	34
	35	/*
	36	* Set when inserting or removing upwards layers.
	37	*/
	38	spinlock_t receive_lock;
	39
	40	};
	41
	42	static int cfmuxl_receive(struct cflayer layr, struct cfpkt pkt);
	43	static int cfmuxl_transmit(struct cflayer layr, struct cfpkt pkt);
	44	static void cfmuxl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
	45	int phyid);
	46	static struct cflayer get_up(struct cfmuxl muxl, u16 id);
	47
	48	struct cflayer *cfmuxl_create(void)
	49	{
	50	struct cfmuxl *this = kmalloc(sizeof(struct cfmuxl), GFP_ATOMIC);
	51	if (!this)
	52	return NULL;
	53	memset(this, 0, sizeof(*this));
	54	this->layer.receive = cfmuxl_receive;
	55	this->layer.transmit = cfmuxl_transmit;
	56	this->layer.ctrlcmd = cfmuxl_ctrlcmd;
	57	INIT_LIST_HEAD(&this->srvl_list);
	58	INIT_LIST_HEAD(&this->frml_list);
	59	spin_lock_init(&this->transmit_lock);
	60	spin_lock_init(&this->receive_lock);
	61	snprintf(this->layer.name, CAIF_LAYER_NAME_SZ, "mux");
	62	return &this->layer;
	63	}
	64
	65	int cfmuxl_set_uplayer(struct cflayer layr, struct cflayer up, u8 linkid)
	66	{
	67	struct cfmuxl *muxl = container_obj(layr);
0b1e9738	68
	69	spin_lock_bh(&muxl->receive_lock);
	70	list_add_rcu(&up->node, &muxl->srvl_list);
	71	spin_unlock_bh(&muxl->receive_lock);
b482cd20 SB	72	return 0;
	73	}
	74
b482cd20 SB	75	int cfmuxl_set_dnlayer(struct cflayer layr, struct cflayer dn, u8 phyid)
	76	{
	77	struct cfmuxl muxl = (struct cfmuxl ) layr;
0b1e9738	78
	79	spin_lock_bh(&muxl->transmit_lock);
	80	list_add_rcu(&dn->node, &muxl->frml_list);
	81	spin_unlock_bh(&muxl->transmit_lock);
b482cd20 SB	82	return 0;
	83	}
	84
	85	static struct cflayer get_from_id(struct list_head list, u16 id)
	86	{
0b1e9738	87	struct cflayer *lyr;
	88	list_for_each_entry_rcu(lyr, list, node) {
	89	if (lyr->id == id)
	90	return lyr;
b482cd20	91	}
0b1e9738	92
b482cd20 SB	93	return NULL;
	94	}
	95
	96	struct cflayer cfmuxl_remove_dnlayer(struct cflayer layr, u8 phyid)
	97	{
	98	struct cfmuxl *muxl = container_obj(layr);
	99	struct cflayer *dn;
0b1e9738	100	int idx = phyid % DN_CACHE_SIZE;
	101
	102	spin_lock_bh(&muxl->transmit_lock);
	103	rcu_assign_pointer(muxl->dn_cache[idx], NULL);
b482cd20	104	dn = get_from_id(&muxl->frml_list, phyid);
0b1e9738	105	if (dn == NULL)
	106	goto out;
	107
	108	list_del_rcu(&dn->node);
b482cd20	109	caif_assert(dn != NULL);
0b1e9738	110	out:
0b1e9738	111	spin_unlock_bh(&muxl->transmit_lock);
b482cd20 SB	112	return dn;
	113	}
	114
b482cd20 SB	115	static struct cflayer get_up(struct cfmuxl muxl, u16 id)
	116	{
	117	struct cflayer *up;
	118	int idx = id % UP_CACHE_SIZE;
0b1e9738	119	up = rcu_dereference(muxl->up_cache[idx]);
b482cd20	120	if (up == NULL \|\| up->id != id) {
0b1e9738	121	spin_lock_bh(&muxl->receive_lock);
b482cd20	122	up = get_from_id(&muxl->srvl_list, id);
0b1e9738	123	rcu_assign_pointer(muxl->up_cache[idx], up);
0b1e9738	124	spin_unlock_bh(&muxl->receive_lock);
b482cd20 SB	125	}
	126	return up;
	127	}
	128
b482cd20 SB	129	static struct cflayer get_dn(struct cfmuxl muxl, struct dev_info *dev_info)
	130	{
	131	struct cflayer *dn;
	132	int idx = dev_info->id % DN_CACHE_SIZE;
0b1e9738	133	dn = rcu_dereference(muxl->dn_cache[idx]);
b482cd20	134	if (dn == NULL \|\| dn->id != dev_info->id) {
0b1e9738	135	spin_lock_bh(&muxl->transmit_lock);
b482cd20	136	dn = get_from_id(&muxl->frml_list, dev_info->id);
0b1e9738	137	rcu_assign_pointer(muxl->dn_cache[idx], dn);
0b1e9738	138	spin_unlock_bh(&muxl->transmit_lock);
b482cd20 SB	139	}
	140	return dn;
	141	}
	142
	143	struct cflayer cfmuxl_remove_uplayer(struct cflayer layr, u8 id)
	144	{
	145	struct cflayer *up;
	146	struct cfmuxl *muxl = container_obj(layr);
0b1e9738	147	int idx = id % UP_CACHE_SIZE;
	148
	149	spin_lock_bh(&muxl->receive_lock);
	150	up = get_from_id(&muxl->srvl_list, id);
5b208656	151	if (up == NULL)
a9a8f107	152	goto out;
0b1e9738	153
	154	rcu_assign_pointer(muxl->up_cache[idx], NULL);
	155	list_del_rcu(&up->node);
a9a8f107	156	out:
0b1e9738	157	spin_unlock_bh(&muxl->receive_lock);
b482cd20 SB	158	return up;
	159	}
	160
	161	static int cfmuxl_receive(struct cflayer layr, struct cfpkt pkt)
	162	{
	163	int ret;
	164	struct cfmuxl *muxl = container_obj(layr);
	165	u8 id;
	166	struct cflayer *up;
	167	if (cfpkt_extr_head(pkt, &id, 1) < 0) {
b31fa5ba	168	pr_err("erroneous Caif Packet\n");
b482cd20 SB	169	cfpkt_destroy(pkt);
	170	return -EPROTO;
	171	}
0b1e9738	172	rcu_read_lock();
b482cd20	173	up = get_up(muxl, id);
0b1e9738	174
b482cd20	175	if (up == NULL) {
0b1e9738	176	pr_debug("Received data on unknown link ID = %d (0x%x)"
0b1e9738	177	" up == NULL", id, id);
b482cd20 SB	178	cfpkt_destroy(pkt);
	179	/*
	180	* Don't return ERROR, since modem misbehaves and sends out
	181	* flow on before linksetup response.
	182	*/
0b1e9738	183
0b1e9738	184	rcu_read_unlock();
b482cd20 SB	185	return /* CFGLU_EPROT; */ 0;
b482cd20 SB	186	}
0b1e9738	187
0b1e9738	188	/* We can't hold rcu_lock during receive, so take a ref count instead */
5b208656	189	cfsrvl_get(up);
0b1e9738	190	rcu_read_unlock();
0b1e9738	191
b482cd20	192	ret = up->receive(up, pkt);
0b1e9738	193
5b208656	194	cfsrvl_put(up);
b482cd20 SB	195	return ret;
	196	}
	197
	198	static int cfmuxl_transmit(struct cflayer layr, struct cfpkt pkt)
	199	{
b482cd20	200	struct cfmuxl *muxl = container_obj(layr);
0b1e9738	201	int err;
b482cd20 SB	202	u8 linkid;
	203	struct cflayer *dn;
	204	struct caif_payload_info *info = cfpkt_info(pkt);
39b9afbb	205	BUG_ON(!info);
0b1e9738	206
	207	rcu_read_lock();
	208
39b9afbb	209	dn = get_dn(muxl, info->dev_info);
b482cd20	210	if (dn == NULL) {
0b1e9738	211	pr_debug("Send data on unknown phy ID = %d (0x%x)\n",
b31fa5ba	212	info->dev_info->id, info->dev_info->id);
0b1e9738	213	rcu_read_unlock();
0b1e9738	214	cfpkt_destroy(pkt);
b482cd20 SB	215	return -ENOTCONN;
b482cd20 SB	216	}
0b1e9738	217
b482cd20 SB	218	info->hdr_len += 1;
	219	linkid = info->channel_id;
	220	cfpkt_add_head(pkt, &linkid, 1);
0b1e9738	221
	222	/* We can't hold rcu_lock during receive, so take a ref count instead */
	223	cffrml_hold(dn);
	224
	225	rcu_read_unlock();
	226
	227	err = dn->transmit(dn, pkt);
	228
	229	cffrml_put(dn);
	230	return err;
b482cd20 SB	231	}
	232
	233	static void cfmuxl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
	234	int phyid)
	235	{
	236	struct cfmuxl *muxl = container_obj(layr);
b482cd20	237	struct cflayer *layer;
0b1e9738	238
	239	rcu_read_lock();
	240	list_for_each_entry_rcu(layer, &muxl->srvl_list, node) {
	241	if (cfsrvl_phyid_match(layer, phyid) && layer->ctrlcmd)
	242	/* NOTE: ctrlcmd is not allowed to block */
b482cd20 SB	243	layer->ctrlcmd(layer, ctrl, phyid);
b482cd20 SB	244	}
0b1e9738	245	rcu_read_unlock();
b482cd20	246	}