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