cfutill.c

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/*
 * Copyright (C) ST-Ericsson AB 2010
 * Author:  Sjur Brendeland/[email protected]
 * License terms: GNU General Public License (GPL) version 2
 */

#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__

#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <net/caif/caif_layer.h>
#include <net/caif/cfsrvl.h>
#include <net/caif/cfpkt.h>

#define container_obj(layr) ((struct cfsrvl *) layr)
#define UTIL_PAYLOAD  0x00
#define UTIL_CMD_BIT  0x80
#define UTIL_REMOTE_SHUTDOWN 0x82
#define UTIL_FLOW_OFF 0x81
#define UTIL_FLOW_ON  0x80

static int cfutill_receive(struct cflayer *layr, struct cfpkt *pkt);
static int cfutill_transmit(struct cflayer *layr, struct cfpkt *pkt);

struct cflayer *cfutill_create(u8 channel_id, struct dev_info *dev_info)
{
    struct cfsrvl *util = kzalloc(sizeof(struct cfsrvl), GFP_ATOMIC);
    if (!util)
        return NULL;
    caif_assert(offsetof(struct cfsrvl, layer) == 0);
    cfsrvl_init(util, channel_id, dev_info, true);
    util->layer.receive = cfutill_receive;
    util->layer.transmit = cfutill_transmit;
    snprintf(util->layer.name, CAIF_LAYER_NAME_SZ - 1, "util1");
    return &util->layer;
}

static int cfutill_receive(struct cflayer *layr, struct cfpkt *pkt)
{
    u8 cmd = -1;
    struct cfsrvl *service = container_obj(layr);
    caif_assert(layr != NULL);
    caif_assert(layr->up != NULL);
    caif_assert(layr->up->receive != NULL);
    caif_assert(layr->up->ctrlcmd != NULL);
    if (cfpkt_extr_head(pkt, &cmd, 1) < 0) {
        pr_err("Packet is erroneous!\n");
        cfpkt_destroy(pkt);
        return -EPROTO;
    }

    switch (cmd) {
    case UTIL_PAYLOAD:
        return layr->up->receive(layr->up, pkt);
    case UTIL_FLOW_OFF:
        layr->ctrlcmd(layr, CAIF_CTRLCMD_FLOW_OFF_IND, 0);
        cfpkt_destroy(pkt);
        return 0;
    case UTIL_FLOW_ON:
        layr->ctrlcmd(layr, CAIF_CTRLCMD_FLOW_ON_IND, 0);
        cfpkt_destroy(pkt);
        return 0;
    case UTIL_REMOTE_SHUTDOWN:  /* Remote Shutdown Request */
        pr_err("REMOTE SHUTDOWN REQUEST RECEIVED\n");
        layr->ctrlcmd(layr, CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND, 0);
        service->open = false;
        cfpkt_destroy(pkt);
        return 0;
    default:
        cfpkt_destroy(pkt);
        pr_warn("Unknown service control %d (0x%x)\n", cmd, cmd);
        return -EPROTO;
    }
}

static int cfutill_transmit(struct cflayer *layr, struct cfpkt *pkt)
{
    u8 zero = 0;
    struct caif_payload_info *info;
    int ret;
    struct cfsrvl *service = container_obj(layr);
    caif_assert(layr != NULL);
    caif_assert(layr->dn != NULL);
    caif_assert(layr->dn->transmit != NULL);

    if (!cfsrvl_ready(service, &ret)) {
        cfpkt_destroy(pkt);
        return ret;
    }

    cfpkt_add_head(pkt, &zero, 1);
    /* Add info for MUX-layer to route the packet out. */
    info = cfpkt_info(pkt);
    info->channel_id = service->layer.id;
    /*
     * To optimize alignment, we add up the size of CAIF header before
     * payload.
     */
    info->hdr_len = 1;
    info->dev_info = &service->dev_info;
    return layr->dn->transmit(layr->dn, pkt);
}