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/net/caif/cffrml.c

http://github.com/mirrors/linux
C | 197 lines | 156 code | 26 blank | 15 comment | 27 complexity | 9b2054b88d5a8502f97df05a52208cf2 MD5 | raw file
  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * CAIF Framing Layer.
  4 *
  5 * Copyright (C) ST-Ericsson AB 2010
  6 * Author:	Sjur Brendeland
  7 */
  8
  9#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
 10
 11#include <linux/stddef.h>
 12#include <linux/spinlock.h>
 13#include <linux/slab.h>
 14#include <linux/crc-ccitt.h>
 15#include <linux/netdevice.h>
 16#include <net/caif/caif_layer.h>
 17#include <net/caif/cfpkt.h>
 18#include <net/caif/cffrml.h>
 19
 20#define container_obj(layr) container_of(layr, struct cffrml, layer)
 21
 22struct cffrml {
 23	struct cflayer layer;
 24	bool dofcs;		/* !< FCS active */
 25	int __percpu		*pcpu_refcnt;
 26};
 27
 28static int cffrml_receive(struct cflayer *layr, struct cfpkt *pkt);
 29static int cffrml_transmit(struct cflayer *layr, struct cfpkt *pkt);
 30static void cffrml_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
 31			   int phyid);
 32
 33static u32 cffrml_rcv_error;
 34static u32 cffrml_rcv_checsum_error;
 35struct cflayer *cffrml_create(u16 phyid, bool use_fcs)
 36{
 37	struct cffrml *this = kzalloc(sizeof(struct cffrml), GFP_ATOMIC);
 38	if (!this)
 39		return NULL;
 40	this->pcpu_refcnt = alloc_percpu(int);
 41	if (this->pcpu_refcnt == NULL) {
 42		kfree(this);
 43		return NULL;
 44	}
 45
 46	caif_assert(offsetof(struct cffrml, layer) == 0);
 47
 48	this->layer.receive = cffrml_receive;
 49	this->layer.transmit = cffrml_transmit;
 50	this->layer.ctrlcmd = cffrml_ctrlcmd;
 51	snprintf(this->layer.name, CAIF_LAYER_NAME_SZ, "frm%d", phyid);
 52	this->dofcs = use_fcs;
 53	this->layer.id = phyid;
 54	return (struct cflayer *) this;
 55}
 56
 57void cffrml_free(struct cflayer *layer)
 58{
 59	struct cffrml *this = container_obj(layer);
 60	free_percpu(this->pcpu_refcnt);
 61	kfree(layer);
 62}
 63
 64void cffrml_set_uplayer(struct cflayer *this, struct cflayer *up)
 65{
 66	this->up = up;
 67}
 68
 69void cffrml_set_dnlayer(struct cflayer *this, struct cflayer *dn)
 70{
 71	this->dn = dn;
 72}
 73
 74static u16 cffrml_checksum(u16 chks, void *buf, u16 len)
 75{
 76	/* FIXME: FCS should be moved to glue in order to use OS-Specific
 77	 * solutions
 78	 */
 79	return crc_ccitt(chks, buf, len);
 80}
 81
 82static int cffrml_receive(struct cflayer *layr, struct cfpkt *pkt)
 83{
 84	u16 tmp;
 85	u16 len;
 86	u16 hdrchks;
 87	int pktchks;
 88	struct cffrml *this;
 89	this = container_obj(layr);
 90
 91	cfpkt_extr_head(pkt, &tmp, 2);
 92	len = le16_to_cpu(tmp);
 93
 94	/* Subtract for FCS on length if FCS is not used. */
 95	if (!this->dofcs)
 96		len -= 2;
 97
 98	if (cfpkt_setlen(pkt, len) < 0) {
 99		++cffrml_rcv_error;
100		pr_err("Framing length error (%d)\n", len);
101		cfpkt_destroy(pkt);
102		return -EPROTO;
103	}
104	/*
105	 * Don't do extract if FCS is false, rather do setlen - then we don't
106	 * get a cache-miss.
107	 */
108	if (this->dofcs) {
109		cfpkt_extr_trail(pkt, &tmp, 2);
110		hdrchks = le16_to_cpu(tmp);
111		pktchks = cfpkt_iterate(pkt, cffrml_checksum, 0xffff);
112		if (pktchks != hdrchks) {
113			cfpkt_add_trail(pkt, &tmp, 2);
114			++cffrml_rcv_error;
115			++cffrml_rcv_checsum_error;
116			pr_info("Frame checksum error (0x%x != 0x%x)\n",
117				hdrchks, pktchks);
118			return -EILSEQ;
119		}
120	}
121	if (cfpkt_erroneous(pkt)) {
122		++cffrml_rcv_error;
123		pr_err("Packet is erroneous!\n");
124		cfpkt_destroy(pkt);
125		return -EPROTO;
126	}
127
128	if (layr->up == NULL) {
129		pr_err("Layr up is missing!\n");
130		cfpkt_destroy(pkt);
131		return -EINVAL;
132	}
133
134	return layr->up->receive(layr->up, pkt);
135}
136
137static int cffrml_transmit(struct cflayer *layr, struct cfpkt *pkt)
138{
139	u16 chks;
140	u16 len;
141	__le16 data;
142
143	struct cffrml *this = container_obj(layr);
144	if (this->dofcs) {
145		chks = cfpkt_iterate(pkt, cffrml_checksum, 0xffff);
146		data = cpu_to_le16(chks);
147		cfpkt_add_trail(pkt, &data, 2);
148	} else {
149		cfpkt_pad_trail(pkt, 2);
150	}
151	len = cfpkt_getlen(pkt);
152	data = cpu_to_le16(len);
153	cfpkt_add_head(pkt, &data, 2);
154	cfpkt_info(pkt)->hdr_len += 2;
155	if (cfpkt_erroneous(pkt)) {
156		pr_err("Packet is erroneous!\n");
157		cfpkt_destroy(pkt);
158		return -EPROTO;
159	}
160
161	if (layr->dn == NULL) {
162		cfpkt_destroy(pkt);
163		return -ENODEV;
164
165	}
166	return layr->dn->transmit(layr->dn, pkt);
167}
168
169static void cffrml_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
170			   int phyid)
171{
172	if (layr->up && layr->up->ctrlcmd)
173		layr->up->ctrlcmd(layr->up, ctrl, layr->id);
174}
175
176void cffrml_put(struct cflayer *layr)
177{
178	struct cffrml *this = container_obj(layr);
179	if (layr != NULL && this->pcpu_refcnt != NULL)
180		this_cpu_dec(*this->pcpu_refcnt);
181}
182
183void cffrml_hold(struct cflayer *layr)
184{
185	struct cffrml *this = container_obj(layr);
186	if (layr != NULL && this->pcpu_refcnt != NULL)
187		this_cpu_inc(*this->pcpu_refcnt);
188}
189
190int cffrml_refcnt_read(struct cflayer *layr)
191{
192	int i, refcnt = 0;
193	struct cffrml *this = container_obj(layr);
194	for_each_possible_cpu(i)
195		refcnt += *per_cpu_ptr(this->pcpu_refcnt, i);
196	return refcnt;
197}