[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 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;
	} 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;
	62	caif_assert(newpkt != NULL);
	63	spin_lock(&layr->sync);
	64
65	if (layr->incomplete_frm != NULL) {
66
67	layr->incomplete_frm =
68	cfpkt_append(layr->incomplete_frm, newpkt, expectlen);
69	pkt = layr->incomplete_frm;
70	} else {
71	pkt = newpkt;
72	}
73	layr->incomplete_frm = NULL;
74
75	do {
76	/* Search for STX at start of pkt if STX is used */
77	if (layr->usestx) {
78	cfpkt_extr_head(pkt, &tmp8, 1);
79	if (tmp8 != CFSERL_STX) {
80	while (cfpkt_more(pkt)
81	&& tmp8 != CFSERL_STX) {
82	cfpkt_extr_head(pkt, &tmp8, 1);
83	}
84	if (!cfpkt_more(pkt)) {
85	cfpkt_destroy(pkt);
86	layr->incomplete_frm = NULL;
87	spin_unlock(&layr->sync);
88	return -EPROTO;
89	}
90	}
91	}
92
93	pkt_len = cfpkt_getlen(pkt);
94
95	/*
96	* pkt_len is the accumulated length of the packet data
97	* we have received so far.
98	* Exit if frame doesn't hold length.
99	*/
100
101	if (pkt_len < 2) {
102	if (layr->usestx)
103	cfpkt_add_head(pkt, &stx, 1);
104	layr->incomplete_frm = pkt;
105	spin_unlock(&layr->sync);
106	return 0;
107	}
108
109	/*
110	* Find length of frame.
111	* expectlen is the length we need for a full frame.
112	*/
113	cfpkt_peek_head(pkt, &tmp, 2);
114	expectlen = le16_to_cpu(tmp) + 2;
115	/*
116	* Frame error handling
117	*/
118	if (expectlen < CAIF_MINIUM_PACKET_SIZE
119	\|\| expectlen > CAIF_MAX_FRAMESIZE) {
120	if (!layr->usestx) {
121	if (pkt != NULL)
122	cfpkt_destroy(pkt);
123	layr->incomplete_frm = NULL;
124	expectlen = 0;
125	spin_unlock(&layr->sync);
126	return -EPROTO;
127	}
128	continue;
129	}
130
131	if (pkt_len < expectlen) {
132	/* Too little received data */
133	if (layr->usestx)
134	cfpkt_add_head(pkt, &stx, 1);
135	layr->incomplete_frm = pkt;
136	spin_unlock(&layr->sync);
137	return 0;
138	}
139
140	/*
141	* Enough data for at least one frame.
142	* Split the frame, if too long
143	*/
144	if (pkt_len > expectlen)
145	tail_pkt = cfpkt_split(pkt, expectlen);
146	else
147	tail_pkt = NULL;
148
149	/* Send the first part of packet upwards.*/
150	spin_unlock(&layr->sync);
151	ret = layr->layer.up->receive(layr->layer.up, pkt);
152	spin_lock(&layr->sync);
153	if (ret == -EILSEQ) {
154	if (layr->usestx) {
155	if (tail_pkt != NULL)
156	pkt = cfpkt_append(pkt, tail_pkt, 0);
157
158	/* Start search for next STX if frame failed */
159	continue;
160	} else {
161	cfpkt_destroy(pkt);
162	pkt = NULL;
163	}
164	}
165
166	pkt = tail_pkt;
167
168	} while (pkt != NULL);
169
170	spin_unlock(&layr->sync);
171	return 0;
172	}
173
174	static int cfserl_transmit(struct cflayer layer, struct cfpkt newpkt)
175	{
176	struct cfserl *layr = container_obj(layer);
177	int ret;
178	u8 tmp8 = CFSERL_STX;
179	if (layr->usestx)
180	cfpkt_add_head(newpkt, &tmp8, 1);
181	ret = layer->dn->transmit(layer->dn, newpkt);
182	if (ret < 0)
183	cfpkt_extr_head(newpkt, &tmp8, 1);
184
185	return ret;
186	}
187
188	static void cfserl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
189	int phyid)
190	{
191	layr->up->ctrlcmd(layr->up, ctrl, phyid);
192	}