diff options
Diffstat (limited to 'net/caif/cfserl.c')
| -rw-r--r-- | net/caif/cfserl.c | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/net/caif/cfserl.c b/net/caif/cfserl.c new file mode 100644 index 000000000..ce60f06d7 --- /dev/null +++ b/net/caif/cfserl.c @@ -0,0 +1,188 @@ +/* + * Copyright (C) ST-Ericsson AB 2010 + * Author: Sjur Brendeland + * 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 <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); + +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; + 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); + 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); +} |