[net-next-2.6.git] / net / caif / cfserl.c

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

#include <linux/stddef.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <net/caif/caif_layer.h>
#include <net/caif/cfpkt.h>
#include <net/caif/cfserl.h>

#define container_obj(layr) ((struct cfserl *) layr)

#define CFSERL_STX 0x02
#define CAIF_MINIUM_PACKET_SIZE 4
struct cfserl {
	struct cflayer layer;
	struct cfpkt *incomplete_frm;
	/* Protects parallel processing of incoming packets */
	spinlock_t sync;
	bool usestx;
};
#define STXLEN(layr) (layr->usestx ? 1 : 0)

static int cfserl_receive(struct cflayer *layr, struct cfpkt *pkt);
static int cfserl_transmit(struct cflayer *layr, struct cfpkt *pkt);
static void cfserl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
				int phyid);

struct cflayer *cfserl_create(int type, int instance, bool use_stx)
{
	struct cfserl *this = kmalloc(sizeof(struct cfserl), GFP_ATOMIC);
	if (!this) {
		pr_warning("CAIF: %s(): Out of memory\n", __func__);
		return NULL;
	}
	caif_assert(offsetof(struct cfserl, layer) == 0);
	memset(this, 0, sizeof(struct cfserl));
	this->layer.receive = cfserl_receive;
	this->layer.transmit = cfserl_transmit;
	this->layer.ctrlcmd = cfserl_ctrlcmd;
	this->layer.type = type;
	this->usestx = use_stx;
	spin_lock_init(&this->sync);
	snprintf(this->layer.name, CAIF_LAYER_NAME_SZ, "ser1");
	return &this->layer;
}

static int cfserl_receive(struct cflayer *l, struct cfpkt *newpkt)
{
	struct cfserl *layr = container_obj(l);
	u16 pkt_len;
	struct cfpkt *pkt = NULL;
	struct cfpkt *tail_pkt = NULL;
	u8 tmp8;
	u16 tmp;
	u8 stx = CFSERL_STX;
	int ret;
	u16 expectlen = 0;

	caif_assert(newpkt != NULL);
	spin_lock(&layr->sync);

	if (layr->incomplete_frm != NULL) {
		layr->incomplete_frm =
		    cfpkt_append(layr->incomplete_frm, newpkt, expectlen);
		pkt = layr->incomplete_frm;
		if (pkt == NULL) {
			spin_unlock(&layr->sync);
			return -ENOMEM;
		}
	} else {
		pkt = newpkt;
	}
	layr->incomplete_frm = NULL;

	do {
		/* Search for STX at start of pkt if STX is used */
		if (layr->usestx) {
			cfpkt_extr_head(pkt, &tmp8, 1);
			if (tmp8 != CFSERL_STX) {
				while (cfpkt_more(pkt)
				       && tmp8 != CFSERL_STX) {
					cfpkt_extr_head(pkt, &tmp8, 1);
				}
				if (!cfpkt_more(pkt)) {
					cfpkt_destroy(pkt);
					layr->incomplete_frm = NULL;
					spin_unlock(&layr->sync);
					return -EPROTO;
				}
			}
		}

		pkt_len = cfpkt_getlen(pkt);

		/*
		 *  pkt_len is the accumulated length of the packet data
		 *  we have received so far.
		 *  Exit if frame doesn't hold length.
		 */

		if (pkt_len < 2) {
			if (layr->usestx)
				cfpkt_add_head(pkt, &stx, 1);
			layr->incomplete_frm = pkt;
			spin_unlock(&layr->sync);
			return 0;
		}

		/*
		 *  Find length of frame.
		 *  expectlen is the length we need for a full frame.
		 */
		cfpkt_peek_head(pkt, &tmp, 2);
		expectlen = le16_to_cpu(tmp) + 2;
		/*
		 * Frame error handling
		 */
		if (expectlen < CAIF_MINIUM_PACKET_SIZE
		    || expectlen > CAIF_MAX_FRAMESIZE) {
			if (!layr->usestx) {
				if (pkt != NULL)
					cfpkt_destroy(pkt);
				layr->incomplete_frm = NULL;
				expectlen = 0;
				spin_unlock(&layr->sync);
				return -EPROTO;
			}
			continue;
		}

		if (pkt_len < expectlen) {
			/* Too little received data */
			if (layr->usestx)
				cfpkt_add_head(pkt, &stx, 1);
			layr->incomplete_frm = pkt;
			spin_unlock(&layr->sync);
			return 0;
		}

		/*
		 * Enough data for at least one frame.
		 * Split the frame, if too long
		 */
		if (pkt_len > expectlen)
			tail_pkt = cfpkt_split(pkt, expectlen);
		else
			tail_pkt = NULL;

		/* Send the first part of packet upwards.*/
		spin_unlock(&layr->sync);
		ret = layr->layer.up->receive(layr->layer.up, pkt);
		spin_lock(&layr->sync);
		if (ret == -EILSEQ) {
			if (layr->usestx) {
				if (tail_pkt != NULL)
					pkt = cfpkt_append(pkt, tail_pkt, 0);
				/* Start search for next STX if frame failed */
				continue;
			} else {
				cfpkt_destroy(pkt);
				pkt = NULL;
			}
		}

		pkt = tail_pkt;

	} while (pkt != NULL);

	spin_unlock(&layr->sync);
	return 0;
}

static int cfserl_transmit(struct cflayer *layer, struct cfpkt *newpkt)
{
	struct cfserl *layr = container_obj(layer);
	int ret;
	u8 tmp8 = CFSERL_STX;
	if (layr->usestx)
		cfpkt_add_head(newpkt, &tmp8, 1);
	ret = layer->dn->transmit(layer->dn, newpkt);
	if (ret < 0)
		cfpkt_extr_head(newpkt, &tmp8, 1);

	return ret;
}

static void cfserl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
				int phyid)
{
	layr->up->ctrlcmd(layr->up, ctrl, phyid);
}
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	*/
	6
	7	#include <linux/stddef.h>
	8	#include <linux/spinlock.h>
	9	#include <linux/slab.h>
	10	#include <net/caif/caif_layer.h>
	11	#include <net/caif/cfpkt.h>
	12	#include <net/caif/cfserl.h>
	13
	14	#define container_obj(layr) ((struct cfserl *) layr)
	15
	16	#define CFSERL_STX 0x02
	17	#define CAIF_MINIUM_PACKET_SIZE 4
	18	struct cfserl {
	19	struct cflayer layer;
	20	struct cfpkt *incomplete_frm;
	21	/* Protects parallel processing of incoming packets */
	22	spinlock_t sync;
	23	bool usestx;
	24	};
	25	#define STXLEN(layr) (layr->usestx ? 1 : 0)
	26
	27	static int cfserl_receive(struct cflayer layr, struct cfpkt pkt);
	28	static int cfserl_transmit(struct cflayer layr, struct cfpkt pkt);
	29	static void cfserl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
	30	int phyid);
	31
	32	struct cflayer *cfserl_create(int type, int instance, bool use_stx)
	33	{
	34	struct cfserl *this = kmalloc(sizeof(struct cfserl), GFP_ATOMIC);
	35	if (!this) {
	36	pr_warning("CAIF: %s(): Out of memory\n", __func__);
	37	return NULL;
	38	}
	39	caif_assert(offsetof(struct cfserl, layer) == 0);
	40	memset(this, 0, sizeof(struct cfserl));
	41	this->layer.receive = cfserl_receive;
	42	this->layer.transmit = cfserl_transmit;
	43	this->layer.ctrlcmd = cfserl_ctrlcmd;
	44	this->layer.type = type;
	45	this->usestx = use_stx;
	46	spin_lock_init(&this->sync);
	47	snprintf(this->layer.name, CAIF_LAYER_NAME_SZ, "ser1");
	48	return &this->layer;
	49	}
	50
	51	static int cfserl_receive(struct cflayer l, struct cfpkt newpkt)
	52	{
	53	struct cfserl *layr = container_obj(l);
	54	u16 pkt_len;
	55	struct cfpkt *pkt = NULL;
	56	struct cfpkt *tail_pkt = NULL;
	57	u8 tmp8;
	58	u16 tmp;
	59	u8 stx = CFSERL_STX;
	60	int ret;
	61	u16 expectlen = 0;
97dc875f	62
b482cd20 SB	63	caif_assert(newpkt != NULL);
	64	spin_lock(&layr->sync);
	65
	66	if (layr->incomplete_frm != NULL) {
b482cd20 SB	67	layr->incomplete_frm =
	68	cfpkt_append(layr->incomplete_frm, newpkt, expectlen);
	69	pkt = layr->incomplete_frm;
97dc875f DC	70	if (pkt == NULL) {
97dc875f DC	71	spin_unlock(&layr->sync);
638e628a	72	return -ENOMEM;
97dc875f	73	}
b482cd20 SB	74	} else {
	75	pkt = newpkt;
	76	}
	77	layr->incomplete_frm = NULL;
	78
	79	do {
	80	/* Search for STX at start of pkt if STX is used */
	81	if (layr->usestx) {
	82	cfpkt_extr_head(pkt, &tmp8, 1);
	83	if (tmp8 != CFSERL_STX) {
	84	while (cfpkt_more(pkt)
	85	&& tmp8 != CFSERL_STX) {
	86	cfpkt_extr_head(pkt, &tmp8, 1);
	87	}
	88	if (!cfpkt_more(pkt)) {
	89	cfpkt_destroy(pkt);
	90	layr->incomplete_frm = NULL;
	91	spin_unlock(&layr->sync);
	92	return -EPROTO;
	93	}
	94	}
	95	}
	96
	97	pkt_len = cfpkt_getlen(pkt);
	98
	99	/*
	100	* pkt_len is the accumulated length of the packet data
	101	* we have received so far.
	102	* Exit if frame doesn't hold length.
	103	*/
	104
	105	if (pkt_len < 2) {
	106	if (layr->usestx)
	107	cfpkt_add_head(pkt, &stx, 1);
	108	layr->incomplete_frm = pkt;
	109	spin_unlock(&layr->sync);
	110	return 0;
	111	}
	112
	113	/*
	114	* Find length of frame.
	115	* expectlen is the length we need for a full frame.
	116	*/
	117	cfpkt_peek_head(pkt, &tmp, 2);
	118	expectlen = le16_to_cpu(tmp) + 2;
	119	/*
	120	* Frame error handling
	121	*/
	122	if (expectlen < CAIF_MINIUM_PACKET_SIZE
	123	\|\| expectlen > CAIF_MAX_FRAMESIZE) {
	124	if (!layr->usestx) {
	125	if (pkt != NULL)
	126	cfpkt_destroy(pkt);
	127	layr->incomplete_frm = NULL;
	128	expectlen = 0;
	129	spin_unlock(&layr->sync);
	130	return -EPROTO;
	131	}
	132	continue;
	133	}
	134
	135	if (pkt_len < expectlen) {
	136	/* Too little received data */
	137	if (layr->usestx)
138	cfpkt_add_head(pkt, &stx, 1);
139	layr->incomplete_frm = pkt;
140	spin_unlock(&layr->sync);
141	return 0;
142	}
143
144	/*
145	* Enough data for at least one frame.
146	* Split the frame, if too long
147	*/
148	if (pkt_len > expectlen)
149	tail_pkt = cfpkt_split(pkt, expectlen);
150	else
151	tail_pkt = NULL;
152
153	/* Send the first part of packet upwards.*/
154	spin_unlock(&layr->sync);
155	ret = layr->layer.up->receive(layr->layer.up, pkt);
156	spin_lock(&layr->sync);
157	if (ret == -EILSEQ) {
158	if (layr->usestx) {
159	if (tail_pkt != NULL)
160	pkt = cfpkt_append(pkt, tail_pkt, 0);
b482cd20 SB	161	/* Start search for next STX if frame failed */
	162	continue;
	163	} else {
	164	cfpkt_destroy(pkt);
	165	pkt = NULL;
	166	}
	167	}
	168
	169	pkt = tail_pkt;
	170
	171	} while (pkt != NULL);
	172
	173	spin_unlock(&layr->sync);
	174	return 0;
	175	}
	176
	177	static int cfserl_transmit(struct cflayer layer, struct cfpkt newpkt)
	178	{
	179	struct cfserl *layr = container_obj(layer);
	180	int ret;
	181	u8 tmp8 = CFSERL_STX;
	182	if (layr->usestx)
	183	cfpkt_add_head(newpkt, &tmp8, 1);
	184	ret = layer->dn->transmit(layer->dn, newpkt);
	185	if (ret < 0)
	186	cfpkt_extr_head(newpkt, &tmp8, 1);
	187
	188	return ret;
	189	}
	190
	191	static void cfserl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
	192	int phyid)
	193	{
	194	layr->up->ctrlcmd(layr->up, ctrl, phyid);
	195	}