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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/net/caif/cfutill.c
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// 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/kernel.h>

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#include <linux/types.h>

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#include <linux/slab.h>

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#include <linux/errno.h>

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#include <net/caif/caif_layer.h>

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#include <net/caif/cfsrvl.h>

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#include <net/caif/cfpkt.h>

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#define container_obj(layr) ((struct cfsrvl *) layr)

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#define UTIL_PAYLOAD  0x00

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#define UTIL_CMD_BIT  0x80

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#define UTIL_REMOTE_SHUTDOWN 0x82

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#define UTIL_FLOW_OFF 0x81

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#define UTIL_FLOW_ON  0x80

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

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

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struct cflayer *cfutill_create(u8 channel_id, struct dev_info *dev_info)

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{

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	struct cfsrvl *util = kzalloc(sizeof(struct cfsrvl), GFP_ATOMIC);

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	if (!util)

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		return NULL;

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	caif_assert(offsetof(struct cfsrvl, layer) == 0);

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	cfsrvl_init(util, channel_id, dev_info, true);

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	util->layer.receive = cfutill_receive;

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	util->layer.transmit = cfutill_transmit;

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	snprintf(util->layer.name, CAIF_LAYER_NAME_SZ, "util1");

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	return &util->layer;

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}

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

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{

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	u8 cmd = -1;

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	struct cfsrvl *service = container_obj(layr);

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	caif_assert(layr != NULL);

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	caif_assert(layr->up != NULL);

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	caif_assert(layr->up->receive != NULL);

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	caif_assert(layr->up->ctrlcmd != NULL);

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	if (cfpkt_extr_head(pkt, &cmd, 1) < 0) {

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		pr_err("Packet is erroneous!\n");

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		cfpkt_destroy(pkt);

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		return -EPROTO;

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	}

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	switch (cmd) {

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	case UTIL_PAYLOAD:

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		return layr->up->receive(layr->up, pkt);

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	case UTIL_FLOW_OFF:

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		layr->ctrlcmd(layr, CAIF_CTRLCMD_FLOW_OFF_IND, 0);

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		cfpkt_destroy(pkt);

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		return 0;

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	case UTIL_FLOW_ON:

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		layr->ctrlcmd(layr, CAIF_CTRLCMD_FLOW_ON_IND, 0);

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		cfpkt_destroy(pkt);

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		return 0;

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	case UTIL_REMOTE_SHUTDOWN:	/* Remote Shutdown Request */

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		pr_err("REMOTE SHUTDOWN REQUEST RECEIVED\n");

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		layr->ctrlcmd(layr, CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND, 0);

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		service->open = false;

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		cfpkt_destroy(pkt);

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		return 0;

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	default:

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		cfpkt_destroy(pkt);

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		pr_warn("Unknown service control %d (0x%x)\n", cmd, cmd);

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		return -EPROTO;

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	}

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}

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

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{

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	u8 zero = 0;

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	struct caif_payload_info *info;

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	int ret;

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	struct cfsrvl *service = container_obj(layr);

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	caif_assert(layr != NULL);

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	caif_assert(layr->dn != NULL);

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	caif_assert(layr->dn->transmit != NULL);

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	if (!cfsrvl_ready(service, &ret)) {

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		cfpkt_destroy(pkt);

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		return ret;

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	}

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	cfpkt_add_head(pkt, &zero, 1);

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	/* Add info for MUX-layer to route the packet out. */

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	info = cfpkt_info(pkt);

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	info->channel_id = service->layer.id;

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	/*

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	 * To optimize alignment, we add up the size of CAIF header before

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	 * payload.

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	 */

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	info->hdr_len = 1;

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	info->dev_info = &service->dev_info;

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	return layr->dn->transmit(layr->dn, pkt);

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}

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