[thirdparty/linux.git] / net / caif / cfserl.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) ST-Ericsson AB 2010
 * Author:	Sjur Brendeland
 */

#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);

void cfserl_release(struct cflayer *layer)
{
	kfree(layer);
}

struct cflayer *cfserl_create(int instance, bool use_stx)
{
	struct cfserl *this = kzalloc(sizeof(struct cfserl), GFP_ATOMIC);
	if (!this)
		return NULL;
	caif_assert(offsetof(struct cfserl, layer) == 0);
	this->layer.receive = cfserl_receive;
	this->layer.transmit = cfserl_transmit;
	this->layer.ctrlcmd = cfserl_ctrlcmd;
	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;
				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);
	u8 tmp8 = CFSERL_STX;
	if (layr->usestx)
		cfpkt_add_head(newpkt, &tmp8, 1);
	return layer->dn->transmit(layer->dn, newpkt);
}

static void cfserl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
			   int phyid)
{
	layr->up->ctrlcmd(layr->up, ctrl, phyid);
}
Commit	Line	Data
af873fce	1	// SPDX-License-Identifier: GPL-2.0-only
b482cd20 SB	2	/*
b482cd20 SB	3	* Copyright (C) ST-Ericsson AB 2010
26ee65e6	4	* Author: Sjur Brendeland
b482cd20 SB	5	*/
b482cd20 SB	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,
3bffc475	32	int phyid);
b482cd20	33
bce130e7 PS	34	void cfserl_release(struct cflayer *layer)
	35	{
	36	kfree(layer);
	37	}
	38
e977b4cf	39	struct cflayer *cfserl_create(int instance, bool use_stx)
b482cd20	40	{
7ac2ed0c JP	41	struct cfserl *this = kzalloc(sizeof(struct cfserl), GFP_ATOMIC);
7ac2ed0c JP	42	if (!this)
b482cd20	43	return NULL;
b482cd20	44	caif_assert(offsetof(struct cfserl, layer) == 0);
b482cd20 SB	45	this->layer.receive = cfserl_receive;
	46	this->layer.transmit = cfserl_transmit;
	47	this->layer.ctrlcmd = cfserl_ctrlcmd;
b482cd20 SB	48	this->usestx = use_stx;
	49	spin_lock_init(&this->sync);
	50	snprintf(this->layer.name, CAIF_LAYER_NAME_SZ, "ser1");
	51	return &this->layer;
	52	}
	53
	54	static int cfserl_receive(struct cflayer l, struct cfpkt newpkt)
	55	{
	56	struct cfserl *layr = container_obj(l);
	57	u16 pkt_len;
	58	struct cfpkt *pkt = NULL;
	59	struct cfpkt *tail_pkt = NULL;
	60	u8 tmp8;
	61	u16 tmp;
	62	u8 stx = CFSERL_STX;
	63	int ret;
	64	u16 expectlen = 0;
97dc875f	65
b482cd20 SB	66	caif_assert(newpkt != NULL);
	67	spin_lock(&layr->sync);
	68
	69	if (layr->incomplete_frm != NULL) {
b482cd20 SB	70	layr->incomplete_frm =
	71	cfpkt_append(layr->incomplete_frm, newpkt, expectlen);
	72	pkt = layr->incomplete_frm;
97dc875f DC	73	if (pkt == NULL) {
97dc875f DC	74	spin_unlock(&layr->sync);
638e628a	75	return -ENOMEM;
97dc875f	76	}
b482cd20 SB	77	} else {
	78	pkt = newpkt;
	79	}
	80	layr->incomplete_frm = NULL;
	81
	82	do {
	83	/* Search for STX at start of pkt if STX is used */
	84	if (layr->usestx) {
	85	cfpkt_extr_head(pkt, &tmp8, 1);
	86	if (tmp8 != CFSERL_STX) {
	87	while (cfpkt_more(pkt)
	88	&& tmp8 != CFSERL_STX) {
	89	cfpkt_extr_head(pkt, &tmp8, 1);
	90	}
	91	if (!cfpkt_more(pkt)) {
	92	cfpkt_destroy(pkt);
	93	layr->incomplete_frm = NULL;
	94	spin_unlock(&layr->sync);
	95	return -EPROTO;
	96	}
	97	}
	98	}
	99
	100	pkt_len = cfpkt_getlen(pkt);
	101
	102	/*
	103	* pkt_len is the accumulated length of the packet data
	104	* we have received so far.
	105	* Exit if frame doesn't hold length.
	106	*/
	107
	108	if (pkt_len < 2) {
	109	if (layr->usestx)
	110	cfpkt_add_head(pkt, &stx, 1);
	111	layr->incomplete_frm = pkt;
	112	spin_unlock(&layr->sync);
	113	return 0;
	114	}
	115
	116	/*
	117	* Find length of frame.
	118	* expectlen is the length we need for a full frame.
	119	*/
	120	cfpkt_peek_head(pkt, &tmp, 2);
	121	expectlen = le16_to_cpu(tmp) + 2;
	122	/*
	123	* Frame error handling
	124	*/
2aa40aef SB	125	if (expectlen < SERIAL_MINIUM_PACKET_SIZE
2aa40aef SB	126	\|\| expectlen > SERIAL_MAX_FRAMESIZE) {
b482cd20 SB	127	if (!layr->usestx) {
	128	if (pkt != NULL)
	129	cfpkt_destroy(pkt);
	130	layr->incomplete_frm = NULL;
b482cd20 SB	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);
b482cd20 SB	182	u8 tmp8 = CFSERL_STX;
	183	if (layr->usestx)
	184	cfpkt_add_head(newpkt, &tmp8, 1);
4dd820c0	185	return layer->dn->transmit(layer->dn, newpkt);
b482cd20 SB	186	}
	187
	188	static void cfserl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
3bffc475	189	int phyid)
b482cd20 SB	190	{
	191	layr->up->ctrlcmd(layr->up, ctrl, phyid);
	192	}