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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /net/caif/cfserl.c
Initial import
Diffstat (limited to 'net/caif/cfserl.c')
-rw-r--r--net/caif/cfserl.c188
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);
+}