1// SPDX-License-Identifier: GPL-2.0-only 2/* 3 * Copyright (C) ST-Ericsson AB 2010 4 * Author: Sjur Brendeland 5 */ 6 7#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__ 8 9#include <linux/stddef.h> 10#include <linux/spinlock.h> 11#include <linux/slab.h> 12#include <net/caif/caif_layer.h> 13#include <net/caif/cfsrvl.h> 14#include <net/caif/cfpkt.h> 15 16 17#define container_obj(layr) ((struct cfsrvl *) layr) 18 19#define DGM_CMD_BIT 0x80 20#define DGM_FLOW_OFF 0x81 21#define DGM_FLOW_ON 0x80 22#define DGM_MTU 1500 23 24static int cfdgml_receive(struct cflayer *layr, struct cfpkt *pkt); 25static int cfdgml_transmit(struct cflayer *layr, struct cfpkt *pkt); 26 27struct cflayer *cfdgml_create(u8 channel_id, struct dev_info *dev_info) 28{ 29 struct cfsrvl *dgm = kzalloc(sizeof(struct cfsrvl), GFP_ATOMIC); 30 if (!dgm) 31 return NULL; 32 caif_assert(offsetof(struct cfsrvl, layer) == 0); 33 cfsrvl_init(dgm, channel_id, dev_info, true); 34 dgm->layer.receive = cfdgml_receive; 35 dgm->layer.transmit = cfdgml_transmit; 36 snprintf(dgm->layer.name, CAIF_LAYER_NAME_SZ, "dgm%d", channel_id); 37 return &dgm->layer; 38} 39 40static int cfdgml_receive(struct cflayer *layr, struct cfpkt *pkt) 41{ 42 u8 cmd = -1; 43 u8 dgmhdr[3]; 44 int ret; 45 caif_assert(layr->up != NULL); 46 caif_assert(layr->receive != NULL); 47 caif_assert(layr->ctrlcmd != NULL); 48 49 if (cfpkt_extr_head(pkt, &cmd, 1) < 0) { 50 pr_err("Packet is erroneous!\n"); 51 cfpkt_destroy(pkt); 52 return -EPROTO; 53 } 54 55 if ((cmd & DGM_CMD_BIT) == 0) { 56 if (cfpkt_extr_head(pkt, &dgmhdr, 3) < 0) { 57 pr_err("Packet is erroneous!\n"); 58 cfpkt_destroy(pkt); 59 return -EPROTO; 60 } 61 ret = layr->up->receive(layr->up, pkt); 62 return ret; 63 } 64 65 switch (cmd) { 66 case DGM_FLOW_OFF: /* FLOW OFF */ 67 layr->ctrlcmd(layr, CAIF_CTRLCMD_FLOW_OFF_IND, 0); 68 cfpkt_destroy(pkt); 69 return 0; 70 case DGM_FLOW_ON: /* FLOW ON */ 71 layr->ctrlcmd(layr, CAIF_CTRLCMD_FLOW_ON_IND, 0); 72 cfpkt_destroy(pkt); 73 return 0; 74 default: 75 cfpkt_destroy(pkt); 76 pr_info("Unknown datagram control %d (0x%x)\n", cmd, cmd); 77 return -EPROTO; 78 } 79} 80 81static int cfdgml_transmit(struct cflayer *layr, struct cfpkt *pkt) 82{ 83 u8 packet_type; 84 u32 zero = 0; 85 struct caif_payload_info *info; 86 struct cfsrvl *service = container_obj(layr); 87 int ret; 88 89 if (!cfsrvl_ready(service, &ret)) { 90 cfpkt_destroy(pkt); 91 return ret; 92 } 93 94 /* STE Modem cannot handle more than 1500 bytes datagrams */ 95 if (cfpkt_getlen(pkt) > DGM_MTU) { 96 cfpkt_destroy(pkt); 97 return -EMSGSIZE; 98 } 99 100 cfpkt_add_head(pkt, &zero, 3); 101 packet_type = 0x08; /* B9 set - UNCLASSIFIED */ 102 cfpkt_add_head(pkt, &packet_type, 1); 103 104 /* Add info for MUX-layer to route the packet out. */ 105 info = cfpkt_info(pkt); 106 info->channel_id = service->layer.id; 107 /* To optimize alignment, we add up the size of CAIF header 108 * before payload. 109 */ 110 info->hdr_len = 4; 111 info->dev_info = &service->dev_info; 112 return layr->dn->transmit(layr->dn, pkt); 113} 114