[deliverable/linux.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
 */

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

#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 SERIAL_MINIUM_PACKET_SIZE 4
#define SERIAL_MAX_FRAMESIZE 4096
struct cfserl {
	struct cflayer layer;
	struct cfpkt *incomplete_frm;
	/* Protects parallel processing of incoming packets */
	spinlock_t sync;
	bool usestx;
};

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_warn("Out of memory\n");
		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 < SERIAL_MINIUM_PACKET_SIZE
		    || expectlen > SERIAL_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
b31fa5ba JP	7	#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
b31fa5ba JP	8
b482cd20 SB	9	#include <linux/stddef.h>
	10	#include <linux/spinlock.h>
	11	#include <linux/slab.h>
	12	#include <net/caif/caif_layer.h>
	13	#include <net/caif/cfpkt.h>
	14	#include <net/caif/cfserl.h>
	15
	16	#define container_obj(layr) ((struct cfserl *) layr)
	17
	18	#define CFSERL_STX 0x02
2aa40aef SB	19	#define SERIAL_MINIUM_PACKET_SIZE 4
2aa40aef SB	20	#define SERIAL_MAX_FRAMESIZE 4096
b482cd20 SB	21	struct cfserl {
	22	struct cflayer layer;
	23	struct cfpkt *incomplete_frm;
	24	/* Protects parallel processing of incoming packets */
	25	spinlock_t sync;
	26	bool usestx;
	27	};
b482cd20 SB	28
	29	static int cfserl_receive(struct cflayer layr, struct cfpkt pkt);
	30	static int cfserl_transmit(struct cflayer layr, struct cfpkt pkt);
	31	static void cfserl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
	32	int phyid);
	33
	34	struct cflayer *cfserl_create(int type, int instance, bool use_stx)
	35	{
	36	struct cfserl *this = kmalloc(sizeof(struct cfserl), GFP_ATOMIC);
	37	if (!this) {
b31fa5ba	38	pr_warn("Out of memory\n");
b482cd20 SB	39	return NULL;
	40	}
	41	caif_assert(offsetof(struct cfserl, layer) == 0);
	42	memset(this, 0, sizeof(struct cfserl));
	43	this->layer.receive = cfserl_receive;
	44	this->layer.transmit = cfserl_transmit;
	45	this->layer.ctrlcmd = cfserl_ctrlcmd;
	46	this->layer.type = type;
	47	this->usestx = use_stx;
	48	spin_lock_init(&this->sync);
	49	snprintf(this->layer.name, CAIF_LAYER_NAME_SZ, "ser1");
	50	return &this->layer;
	51	}
	52
	53	static int cfserl_receive(struct cflayer l, struct cfpkt newpkt)
	54	{
	55	struct cfserl *layr = container_obj(l);
	56	u16 pkt_len;
	57	struct cfpkt *pkt = NULL;
	58	struct cfpkt *tail_pkt = NULL;
	59	u8 tmp8;
	60	u16 tmp;
	61	u8 stx = CFSERL_STX;
	62	int ret;
	63	u16 expectlen = 0;
97dc875f	64
b482cd20 SB	65	caif_assert(newpkt != NULL);
	66	spin_lock(&layr->sync);
	67
	68	if (layr->incomplete_frm != NULL) {
b482cd20 SB	69	layr->incomplete_frm =
	70	cfpkt_append(layr->incomplete_frm, newpkt, expectlen);
	71	pkt = layr->incomplete_frm;
97dc875f DC	72	if (pkt == NULL) {
97dc875f DC	73	spin_unlock(&layr->sync);
638e628a	74	return -ENOMEM;
97dc875f	75	}
b482cd20 SB	76	} else {
	77	pkt = newpkt;
	78	}
	79	layr->incomplete_frm = NULL;
	80
	81	do {
	82	/* Search for STX at start of pkt if STX is used */
	83	if (layr->usestx) {
	84	cfpkt_extr_head(pkt, &tmp8, 1);
	85	if (tmp8 != CFSERL_STX) {
	86	while (cfpkt_more(pkt)
	87	&& tmp8 != CFSERL_STX) {
	88	cfpkt_extr_head(pkt, &tmp8, 1);
	89	}
	90	if (!cfpkt_more(pkt)) {
	91	cfpkt_destroy(pkt);
	92	layr->incomplete_frm = NULL;
	93	spin_unlock(&layr->sync);
	94	return -EPROTO;
	95	}
	96	}
	97	}
	98
	99	pkt_len = cfpkt_getlen(pkt);
	100
	101	/*
	102	* pkt_len is the accumulated length of the packet data
	103	* we have received so far.
	104	* Exit if frame doesn't hold length.
	105	*/
	106
	107	if (pkt_len < 2) {
	108	if (layr->usestx)
	109	cfpkt_add_head(pkt, &stx, 1);
	110	layr->incomplete_frm = pkt;
	111	spin_unlock(&layr->sync);
	112	return 0;
	113	}
	114
	115	/*
	116	* Find length of frame.
	117	* expectlen is the length we need for a full frame.
	118	*/
	119	cfpkt_peek_head(pkt, &tmp, 2);
	120	expectlen = le16_to_cpu(tmp) + 2;
	121	/*
	122	* Frame error handling
	123	*/
2aa40aef SB	124	if (expectlen < SERIAL_MINIUM_PACKET_SIZE
2aa40aef SB	125	\|\| expectlen > SERIAL_MAX_FRAMESIZE) {
b482cd20 SB	126	if (!layr->usestx) {
	127	if (pkt != NULL)
	128	cfpkt_destroy(pkt);
	129	layr->incomplete_frm = NULL;
	130	expectlen = 0;
	131	spin_unlock(&layr->sync);
	132	return -EPROTO;
	133	}
	134	continue;
	135	}
	136
	137	if (pkt_len < expectlen) {
	138	/* Too little received data */
	139	if (layr->usestx)
	140	cfpkt_add_head(pkt, &stx, 1);
	141	layr->incomplete_frm = pkt;
	142	spin_unlock(&layr->sync);
	143	return 0;
	144	}
	145
	146	/*
	147	* Enough data for at least one frame.
	148	* Split the frame, if too long
	149	*/
	150	if (pkt_len > expectlen)
	151	tail_pkt = cfpkt_split(pkt, expectlen);
	152	else
	153	tail_pkt = NULL;
	154
	155	/* Send the first part of packet upwards.*/
	156	spin_unlock(&layr->sync);
	157	ret = layr->layer.up->receive(layr->layer.up, pkt);
	158	spin_lock(&layr->sync);
	159	if (ret == -EILSEQ) {
	160	if (layr->usestx) {
	161	if (tail_pkt != NULL)
	162	pkt = cfpkt_append(pkt, tail_pkt, 0);
b482cd20 SB	163	/* Start search for next STX if frame failed */
	164	continue;
	165	} else {
	166	cfpkt_destroy(pkt);
	167	pkt = NULL;
	168	}
	169	}
	170
	171	pkt = tail_pkt;
	172
	173	} while (pkt != NULL);
	174
	175	spin_unlock(&layr->sync);
	176	return 0;
	177	}
	178
	179	static int cfserl_transmit(struct cflayer layer, struct cfpkt newpkt)
	180	{
	181	struct cfserl *layr = container_obj(layer);
	182	int ret;
	183	u8 tmp8 = CFSERL_STX;
	184	if (layr->usestx)
	185	cfpkt_add_head(newpkt, &tmp8, 1);
	186	ret = layer->dn->transmit(layer->dn, newpkt);
	187	if (ret < 0)
	188	cfpkt_extr_head(newpkt, &tmp8, 1);
	189
	190	return ret;
	191	}
	192
	193	static void cfserl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
	194	int phyid)
	195	{
	196	layr->up->ctrlcmd(layr->up, ctrl, phyid);
	197	}