/* * CAIF Framing Layer. * * 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 <linux/crc-ccitt.h> #include <net/caif/caif_layer.h> #include <net/caif/cfpkt.h> #include <net/caif/cffrml.h> #define container_obj(layr) container_of(layr, struct cffrml, layer) struct cffrml { struct cflayer layer; bool dofcs; /* !< FCS active */ }; static int cffrml_receive(struct cflayer *layr, struct cfpkt *pkt); static int cffrml_transmit(struct cflayer *layr, struct cfpkt *pkt); static void cffrml_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl, int phyid); static u32 cffrml_rcv_error; static u32 cffrml_rcv_checsum_error; struct cflayer *cffrml_create(u16 phyid, bool use_fcs) { struct cffrml *this = kmalloc(sizeof(struct cffrml), GFP_ATOMIC); if (!this) { pr_warn("Out of memory\n"); return NULL; } caif_assert(offsetof(struct cffrml, layer) == 0); memset(this, 0, sizeof(struct cflayer)); this->layer.receive = cffrml_receive; this->layer.transmit = cffrml_transmit; this->layer.ctrlcmd = cffrml_ctrlcmd; snprintf(this->layer.name, CAIF_LAYER_NAME_SZ, "frm%d", phyid); this->dofcs = use_fcs; this->layer.id = phyid; return (struct cflayer *) this; } void cffrml_set_uplayer(struct cflayer *this, struct cflayer *up) { this->up = up; } void cffrml_set_dnlayer(struct cflayer *this, struct cflayer *dn) { this->dn = dn; } static u16 cffrml_checksum(u16 chks, void *buf, u16 len) { /* FIXME: FCS should be moved to glue in order to use OS-Specific * solutions */ return crc_ccitt(chks, buf, len); } static int cffrml_receive(struct cflayer *layr, struct cfpkt *pkt) { u16 tmp; u16 len; u16 hdrchks; u16 pktchks; struct cffrml *this; this = container_obj(layr); cfpkt_extr_head(pkt, &tmp, 2); len = le16_to_cpu(tmp); /* Subtract for FCS on length if FCS is not used. */ if (!this->dofcs) len -= 2; if (cfpkt_setlen(pkt, len) < 0) { ++cffrml_rcv_error; pr_err("Framing length error (%d)\n", len); cfpkt_destroy(pkt); return -EPROTO; } /* * Don't do extract if FCS is false, rather do setlen - then we don't * get a cache-miss. */ if (this->dofcs) { cfpkt_extr_trail(pkt, &tmp, 2); hdrchks = le16_to_cpu(tmp); pktchks = cfpkt_iterate(pkt, cffrml_checksum, 0xffff); if (pktchks != hdrchks) { cfpkt_add_trail(pkt, &tmp, 2); ++cffrml_rcv_error; ++cffrml_rcv_checsum_error; pr_info("Frame checksum error (0x%x != 0x%x)\n", hdrchks, pktchks); return -EILSEQ; } } if (cfpkt_erroneous(pkt)) { ++cffrml_rcv_error; pr_err("Packet is erroneous!\n"); cfpkt_destroy(pkt); return -EPROTO; } return layr->up->receive(layr->up, pkt); } static int cffrml_transmit(struct cflayer *layr, struct cfpkt *pkt) { int tmp; u16 chks; u16 len; int ret; struct cffrml *this = container_obj(layr); if (this->dofcs) { chks = cfpkt_iterate(pkt, cffrml_checksum, 0xffff); tmp = cpu_to_le16(chks); cfpkt_add_trail(pkt, &tmp, 2); } else { cfpkt_pad_trail(pkt, 2); } len = cfpkt_getlen(pkt); tmp = cpu_to_le16(len); cfpkt_add_head(pkt, &tmp, 2); cfpkt_info(pkt)->hdr_len += 2; if (cfpkt_erroneous(pkt)) { pr_err("Packet is erroneous!\n"); return -EPROTO; } ret = layr->dn->transmit(layr->dn, pkt); if (ret < 0) { /* Remove header on faulty packet. */ cfpkt_extr_head(pkt, &tmp, 2); } return ret; } static void cffrml_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl, int phyid) { if (layr->up->ctrlcmd) layr->up->ctrlcmd(layr->up, ctrl, layr->id); }