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188 lines
4.3 KiB
188 lines
4.3 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Copyright (C) ST-Ericsson AB 2010 |
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* Author: Sjur Brendeland |
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*/ |
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#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__ |
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#include <linux/stddef.h> |
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#include <linux/spinlock.h> |
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#include <linux/slab.h> |
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#include <net/caif/caif_layer.h> |
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#include <net/caif/cfpkt.h> |
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#include <net/caif/cfserl.h> |
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#define container_obj(layr) ((struct cfserl *) layr) |
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#define CFSERL_STX 0x02 |
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#define SERIAL_MINIUM_PACKET_SIZE 4 |
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#define SERIAL_MAX_FRAMESIZE 4096 |
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struct cfserl { |
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struct cflayer layer; |
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struct cfpkt *incomplete_frm; |
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/* Protects parallel processing of incoming packets */ |
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spinlock_t sync; |
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bool usestx; |
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}; |
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static int cfserl_receive(struct cflayer *layr, struct cfpkt *pkt); |
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static int cfserl_transmit(struct cflayer *layr, struct cfpkt *pkt); |
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static void cfserl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl, |
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int phyid); |
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struct cflayer *cfserl_create(int instance, bool use_stx) |
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{ |
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struct cfserl *this = kzalloc(sizeof(struct cfserl), GFP_ATOMIC); |
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if (!this) |
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return NULL; |
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caif_assert(offsetof(struct cfserl, layer) == 0); |
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this->layer.receive = cfserl_receive; |
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this->layer.transmit = cfserl_transmit; |
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this->layer.ctrlcmd = cfserl_ctrlcmd; |
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this->usestx = use_stx; |
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spin_lock_init(&this->sync); |
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snprintf(this->layer.name, CAIF_LAYER_NAME_SZ, "ser1"); |
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return &this->layer; |
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} |
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static int cfserl_receive(struct cflayer *l, struct cfpkt *newpkt) |
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{ |
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struct cfserl *layr = container_obj(l); |
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u16 pkt_len; |
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struct cfpkt *pkt = NULL; |
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struct cfpkt *tail_pkt = NULL; |
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u8 tmp8; |
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u16 tmp; |
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u8 stx = CFSERL_STX; |
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int ret; |
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u16 expectlen = 0; |
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caif_assert(newpkt != NULL); |
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spin_lock(&layr->sync); |
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if (layr->incomplete_frm != NULL) { |
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layr->incomplete_frm = |
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cfpkt_append(layr->incomplete_frm, newpkt, expectlen); |
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pkt = layr->incomplete_frm; |
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if (pkt == NULL) { |
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spin_unlock(&layr->sync); |
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return -ENOMEM; |
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} |
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} else { |
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pkt = newpkt; |
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} |
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layr->incomplete_frm = NULL; |
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do { |
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/* Search for STX at start of pkt if STX is used */ |
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if (layr->usestx) { |
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cfpkt_extr_head(pkt, &tmp8, 1); |
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if (tmp8 != CFSERL_STX) { |
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while (cfpkt_more(pkt) |
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&& tmp8 != CFSERL_STX) { |
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cfpkt_extr_head(pkt, &tmp8, 1); |
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} |
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if (!cfpkt_more(pkt)) { |
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cfpkt_destroy(pkt); |
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layr->incomplete_frm = NULL; |
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spin_unlock(&layr->sync); |
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return -EPROTO; |
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} |
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} |
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} |
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pkt_len = cfpkt_getlen(pkt); |
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/* |
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* pkt_len is the accumulated length of the packet data |
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* we have received so far. |
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* Exit if frame doesn't hold length. |
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*/ |
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if (pkt_len < 2) { |
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if (layr->usestx) |
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cfpkt_add_head(pkt, &stx, 1); |
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layr->incomplete_frm = pkt; |
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spin_unlock(&layr->sync); |
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return 0; |
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} |
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/* |
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* Find length of frame. |
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* expectlen is the length we need for a full frame. |
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*/ |
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cfpkt_peek_head(pkt, &tmp, 2); |
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expectlen = le16_to_cpu(tmp) + 2; |
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/* |
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* Frame error handling |
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*/ |
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if (expectlen < SERIAL_MINIUM_PACKET_SIZE |
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|| expectlen > SERIAL_MAX_FRAMESIZE) { |
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if (!layr->usestx) { |
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if (pkt != NULL) |
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cfpkt_destroy(pkt); |
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layr->incomplete_frm = NULL; |
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expectlen = 0; |
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spin_unlock(&layr->sync); |
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return -EPROTO; |
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} |
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continue; |
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} |
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if (pkt_len < expectlen) { |
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/* Too little received data */ |
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if (layr->usestx) |
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cfpkt_add_head(pkt, &stx, 1); |
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layr->incomplete_frm = pkt; |
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spin_unlock(&layr->sync); |
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return 0; |
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} |
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/* |
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* Enough data for at least one frame. |
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* Split the frame, if too long |
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*/ |
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if (pkt_len > expectlen) |
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tail_pkt = cfpkt_split(pkt, expectlen); |
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else |
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tail_pkt = NULL; |
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/* Send the first part of packet upwards.*/ |
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spin_unlock(&layr->sync); |
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ret = layr->layer.up->receive(layr->layer.up, pkt); |
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spin_lock(&layr->sync); |
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if (ret == -EILSEQ) { |
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if (layr->usestx) { |
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if (tail_pkt != NULL) |
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pkt = cfpkt_append(pkt, tail_pkt, 0); |
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/* Start search for next STX if frame failed */ |
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continue; |
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} else { |
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cfpkt_destroy(pkt); |
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pkt = NULL; |
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} |
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} |
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pkt = tail_pkt; |
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} while (pkt != NULL); |
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spin_unlock(&layr->sync); |
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return 0; |
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} |
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static int cfserl_transmit(struct cflayer *layer, struct cfpkt *newpkt) |
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{ |
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struct cfserl *layr = container_obj(layer); |
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u8 tmp8 = CFSERL_STX; |
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if (layr->usestx) |
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cfpkt_add_head(newpkt, &tmp8, 1); |
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return layer->dn->transmit(layer->dn, newpkt); |
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} |
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static void cfserl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl, |
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int phyid) |
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{ |
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layr->up->ctrlcmd(layr->up, ctrl, phyid); |
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}
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