drivers/net/wireless/brcm80211/brcmfmac/dhd_cdc.c - nest-hello/linux-3.10 - Git at Google

 /*
  * Copyright (c) 2010 Broadcom Corporation
  *
  * Permission to use, copy, modify, and/or distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
  * copyright notice and this permission notice appear in all copies.
  *
  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
  * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
  * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
  * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */

 /*******************************************************************************
  * Communicates with the dongle by using dcmd codes.
  * For certain dcmd codes, the dongle interprets string data from the host.
  ******************************************************************************/

 #include <linux/types.h>
 #include <linux/netdevice.h>

 #include <brcmu_utils.h>
 #include <brcmu_wifi.h>

 #include "dhd.h"
 #include "dhd_proto.h"
 #include "dhd_bus.h"
 #include "fwsignal.h"
 #include "dhd_dbg.h"

 struct brcmf_proto_cdc_dcmd {
 	__le32 cmd;	/* dongle command value */
 	__le32 len;	/* lower 16: output buflen;
 			 * upper 16: input buflen (excludes header) */
 	__le32 flags;	/* flag defns given below */
 	__le32 status;	/* status code returned from the device */
 };

 /* Max valid buffer size that can be sent to the dongle */
 #define CDC_MAX_MSG_SIZE	(ETH_FRAME_LEN+ETH_FCS_LEN)

 /* CDC flag definitions */
 #define CDC_DCMD_ERROR		0x01	/* 1=cmd failed */
 #define CDC_DCMD_SET		0x02	/* 0=get, 1=set cmd */
 #define CDC_DCMD_IF_MASK	0xF000		/* I/F index */
 #define CDC_DCMD_IF_SHIFT	12
 #define CDC_DCMD_ID_MASK	0xFFFF0000	/* id an cmd pairing */
 #define CDC_DCMD_ID_SHIFT	16		/* ID Mask shift bits */
 #define CDC_DCMD_ID(flags)	\
 	(((flags) & CDC_DCMD_ID_MASK) >> CDC_DCMD_ID_SHIFT)

 /*
  * BDC header - Broadcom specific extension of CDC.
  * Used on data packets to convey priority across USB.
  */
 #define	BDC_HEADER_LEN		4
 #define BDC_PROTO_VER		2	/* Protocol version */
 #define BDC_FLAG_VER_MASK	0xf0	/* Protocol version mask */
 #define BDC_FLAG_VER_SHIFT	4	/* Protocol version shift */
 #define BDC_FLAG_SUM_GOOD	0x04	/* Good RX checksums */
 #define BDC_FLAG_SUM_NEEDED	0x08	/* Dongle needs to do TX checksums */
 #define BDC_PRIORITY_MASK	0x7
 #define BDC_FLAG2_IF_MASK	0x0f	/* packet rx interface in APSTA */
 #define BDC_FLAG2_IF_SHIFT	0

 #define BDC_GET_IF_IDX(hdr) \
 	((int)((((hdr)->flags2) & BDC_FLAG2_IF_MASK) >> BDC_FLAG2_IF_SHIFT))
 #define BDC_SET_IF_IDX(hdr, idx) \
 	((hdr)->flags2 = (((hdr)->flags2 & ~BDC_FLAG2_IF_MASK) | \
 	((idx) << BDC_FLAG2_IF_SHIFT)))

 /**
  * struct brcmf_proto_bdc_header - BDC header format
  *
  * @flags: flags contain protocol and checksum info.
  * @priority: 802.1d priority and USB flow control info (bit 4:7).
  * @flags2: additional flags containing dongle interface index.
  * @data_offset: start of packet data. header is following by firmware signals.
  */
 struct brcmf_proto_bdc_header {
 	u8 flags;
 	u8 priority;
 	u8 flags2;
 	u8 data_offset;
 };

 /*
  * maximum length of firmware signal data between
  * the BDC header and packet data in the tx path.
  */
 #define BRCMF_PROT_FW_SIGNAL_MAX_TXBYTES	12

 #define RETRIES 2 /* # of retries to retrieve matching dcmd response */
 #define BUS_HEADER_LEN	(16+64)		/* Must be atleast SDPCM_RESERVE
 					 * (amount of header tha might be added)
 					 * plus any space that might be needed
 					 * for bus alignment padding.
 					 */
 #define ROUND_UP_MARGIN	2048	/* Biggest bus block size possible for
 				 * round off at the end of buffer
 				 * Currently is SDIO
 				 */

 struct brcmf_proto {
 	u16 reqid;
 	u8 bus_header[BUS_HEADER_LEN];
 	struct brcmf_proto_cdc_dcmd msg;
 	unsigned char buf[BRCMF_DCMD_MAXLEN + ROUND_UP_MARGIN];
 };

 static int brcmf_proto_cdc_msg(struct brcmf_pub *drvr)
 {
 	struct brcmf_proto *prot = drvr->prot;
 	int len = le32_to_cpu(prot->msg.len) +
 			sizeof(struct brcmf_proto_cdc_dcmd);

 	brcmf_dbg(CDC, "Enter\n");

 	/* NOTE : cdc->msg.len holds the desired length of the buffer to be
 	 *        returned. Only up to CDC_MAX_MSG_SIZE of this buffer area
 	 *        is actually sent to the dongle
 	 */
 	if (len > CDC_MAX_MSG_SIZE)
 		len = CDC_MAX_MSG_SIZE;

 	/* Send request */
 	return brcmf_bus_txctl(drvr->bus_if, (unsigned char *)&prot->msg, len);
 }

 static int brcmf_proto_cdc_cmplt(struct brcmf_pub *drvr, u32 id, u32 len)
 {
 	int ret;
 	struct brcmf_proto *prot = drvr->prot;

 	brcmf_dbg(CDC, "Enter\n");
 	len += sizeof(struct brcmf_proto_cdc_dcmd);
 	do {
 		ret = brcmf_bus_rxctl(drvr->bus_if, (unsigned char *)&prot->msg,
 				      len);
 		if (ret < 0)
 			break;
 	} while (CDC_DCMD_ID(le32_to_cpu(prot->msg.flags)) != id);

 	return ret;
 }

 int
 brcmf_proto_cdc_query_dcmd(struct brcmf_pub *drvr, int ifidx, uint cmd,
 			       void *buf, uint len)
 {
 	struct brcmf_proto *prot = drvr->prot;
 	struct brcmf_proto_cdc_dcmd *msg = &prot->msg;
 	void *info;
 	int ret = 0, retries = 0;
 	u32 id, flags;

 	brcmf_dbg(CDC, "Enter, cmd %d len %d\n", cmd, len);

 	memset(msg, 0, sizeof(struct brcmf_proto_cdc_dcmd));

 	msg->cmd = cpu_to_le32(cmd);
 	msg->len = cpu_to_le32(len);
 	flags = (++prot->reqid << CDC_DCMD_ID_SHIFT);
 	flags = (flags & ~CDC_DCMD_IF_MASK) |
 		(ifidx << CDC_DCMD_IF_SHIFT);
 	msg->flags = cpu_to_le32(flags);

 	if (buf)
 		memcpy(prot->buf, buf, len);

 	ret = brcmf_proto_cdc_msg(drvr);
 	if (ret < 0) {
 		brcmf_err("brcmf_proto_cdc_msg failed w/status %d\n",
 			  ret);
 		goto done;
 	}

 retry:
 	/* wait for interrupt and get first fragment */
 	ret = brcmf_proto_cdc_cmplt(drvr, prot->reqid, len);
 	if (ret < 0)
 		goto done;

 	flags = le32_to_cpu(msg->flags);
 	id = (flags & CDC_DCMD_ID_MASK) >> CDC_DCMD_ID_SHIFT;

 	if ((id < prot->reqid) && (++retries < RETRIES))
 		goto retry;
 	if (id != prot->reqid) {
 		brcmf_err("%s: unexpected request id %d (expected %d)\n",
 			  brcmf_ifname(drvr, ifidx), id, prot->reqid);
 		ret = -EINVAL;
 		goto done;
 	}

 	/* Check info buffer */
 	info = (void *)&msg[1];

 	/* Copy info buffer */
 	if (buf) {
 		if (ret < (int)len)
 			len = ret;
 		memcpy(buf, info, len);
 	}

 	/* Check the ERROR flag */
 	if (flags & CDC_DCMD_ERROR)
 		ret = le32_to_cpu(msg->status);

 done:
 	return ret;
 }

 int brcmf_proto_cdc_set_dcmd(struct brcmf_pub *drvr, int ifidx, uint cmd,
 				 void *buf, uint len)
 {
 	struct brcmf_proto *prot = drvr->prot;
 	struct brcmf_proto_cdc_dcmd *msg = &prot->msg;
 	int ret = 0;
 	u32 flags, id;

 	brcmf_dbg(CDC, "Enter, cmd %d len %d\n", cmd, len);

 	memset(msg, 0, sizeof(struct brcmf_proto_cdc_dcmd));

 	msg->cmd = cpu_to_le32(cmd);
 	msg->len = cpu_to_le32(len);
 	flags = (++prot->reqid << CDC_DCMD_ID_SHIFT) | CDC_DCMD_SET;
 	flags = (flags & ~CDC_DCMD_IF_MASK) |
 		(ifidx << CDC_DCMD_IF_SHIFT);
 	msg->flags = cpu_to_le32(flags);

 	if (buf)
 		memcpy(prot->buf, buf, len);

 	ret = brcmf_proto_cdc_msg(drvr);
 	if (ret < 0)
 		goto done;

 	ret = brcmf_proto_cdc_cmplt(drvr, prot->reqid, len);
 	if (ret < 0)
 		goto done;

 	flags = le32_to_cpu(msg->flags);
 	id = (flags & CDC_DCMD_ID_MASK) >> CDC_DCMD_ID_SHIFT;

 	if (id != prot->reqid) {
 		brcmf_err("%s: unexpected request id %d (expected %d)\n",
 			  brcmf_ifname(drvr, ifidx), id, prot->reqid);
 		ret = -EINVAL;
 		goto done;
 	}

 	/* Check the ERROR flag */
 	if (flags & CDC_DCMD_ERROR)
 		ret = le32_to_cpu(msg->status);

 done:
 	return ret;
 }

 static bool pkt_sum_needed(struct sk_buff *skb)
 {
 	return skb->ip_summed == CHECKSUM_PARTIAL;
 }

 static void pkt_set_sum_good(struct sk_buff *skb, bool x)
 {
 	skb->ip_summed = (x ? CHECKSUM_UNNECESSARY : CHECKSUM_NONE);
 }

 void brcmf_proto_hdrpush(struct brcmf_pub *drvr, int ifidx, u8 offset,
 			 struct sk_buff *pktbuf)
 {
 	struct brcmf_proto_bdc_header *h;

 	brcmf_dbg(CDC, "Enter\n");

 	/* Push BDC header used to convey priority for buses that don't */
 	skb_push(pktbuf, BDC_HEADER_LEN);

 	h = (struct brcmf_proto_bdc_header *)(pktbuf->data);

 	h->flags = (BDC_PROTO_VER << BDC_FLAG_VER_SHIFT);
 	if (pkt_sum_needed(pktbuf))
 		h->flags |= BDC_FLAG_SUM_NEEDED;

 	h->priority = (pktbuf->priority & BDC_PRIORITY_MASK);
 	h->flags2 = 0;
 	h->data_offset = offset;
 	BDC_SET_IF_IDX(h, ifidx);
 }

 int brcmf_proto_hdrpull(struct brcmf_pub *drvr, bool do_fws, u8 *ifidx,
 			struct sk_buff *pktbuf)
 {
 	struct brcmf_proto_bdc_header *h;

 	brcmf_dbg(CDC, "Enter\n");

 	/* Pop BDC header used to convey priority for buses that don't */

 	if (pktbuf->len <= BDC_HEADER_LEN) {
 		brcmf_dbg(INFO, "rx data too short (%d <= %d)\n",
 			  pktbuf->len, BDC_HEADER_LEN);
 		return -EBADE;
 	}

 	h = (struct brcmf_proto_bdc_header *)(pktbuf->data);

 	*ifidx = BDC_GET_IF_IDX(h);
 	if (*ifidx >= BRCMF_MAX_IFS) {
 		brcmf_err("rx data ifnum out of range (%d)\n", *ifidx);
 		return -EBADE;
 	}
 	/* The ifidx is the idx to map to matching netdev/ifp. When receiving
 	 * events this is easy because it contains the bssidx which maps
 	 * 1-on-1 to the netdev/ifp. But for data frames the ifidx is rcvd.
 	 * bssidx 1 is used for p2p0 and no data can be received or
 	 * transmitted on it. Therefor bssidx is ifidx + 1 if ifidx > 0
 	 */
 	if (*ifidx)
 		(*ifidx)++;

 	if (((h->flags & BDC_FLAG_VER_MASK) >> BDC_FLAG_VER_SHIFT) !=
 	    BDC_PROTO_VER) {
 		brcmf_err("%s: non-BDC packet received, flags 0x%x\n",
 			  brcmf_ifname(drvr, *ifidx), h->flags);
 		return -EBADE;
 	}

 	if (h->flags & BDC_FLAG_SUM_GOOD) {
 		brcmf_dbg(CDC, "%s: BDC rcv, good checksum, flags 0x%x\n",
 			  brcmf_ifname(drvr, *ifidx), h->flags);
 		pkt_set_sum_good(pktbuf, true);
 	}

 	pktbuf->priority = h->priority & BDC_PRIORITY_MASK;

 	skb_pull(pktbuf, BDC_HEADER_LEN);
 	if (do_fws)
 		brcmf_fws_hdrpull(drvr, *ifidx, h->data_offset << 2, pktbuf);
 	else
 		skb_pull(pktbuf, h->data_offset << 2);

 	if (pktbuf->len == 0)
 		return -ENODATA;
 	return 0;
 }

 int brcmf_proto_attach(struct brcmf_pub *drvr)
 {
 	struct brcmf_proto *cdc;

 	cdc = kzalloc(sizeof(struct brcmf_proto), GFP_ATOMIC);
 	if (!cdc)
 		goto fail;

 	/* ensure that the msg buf directly follows the cdc msg struct */
 	if ((unsigned long)(&cdc->msg + 1) != (unsigned long)cdc->buf) {
 		brcmf_err("struct brcmf_proto is not correctly defined\n");
 		goto fail;
 	}

 	drvr->prot = cdc;
 	drvr->hdrlen += BDC_HEADER_LEN + BRCMF_PROT_FW_SIGNAL_MAX_TXBYTES;
 	drvr->bus_if->maxctl = BRCMF_DCMD_MAXLEN +
 			sizeof(struct brcmf_proto_cdc_dcmd) + ROUND_UP_MARGIN;
 	return 0;

 fail:
 	kfree(cdc);
 	return -ENOMEM;
 }

 /* ~NOTE~ What if another thread is waiting on the semaphore?  Holding it? */
 void brcmf_proto_detach(struct brcmf_pub *drvr)
 {
 	kfree(drvr->prot);
 	drvr->prot = NULL;
 }

 void brcmf_proto_stop(struct brcmf_pub *drvr)
 {
 	/* Nothing to do for CDC */
 }
	/*
	* Copyright (c) 2010 Broadcom Corporation
	*
	* Permission to use, copy, modify, and/or distribute this software for any
	* purpose with or without fee is hereby granted, provided that the above
	* copyright notice and this permission notice appear in all copies.
	*
	* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
	* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
	* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
	* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
	* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
	* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
	* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
	*/

	/*******************************************************************************
	* Communicates with the dongle by using dcmd codes.
	* For certain dcmd codes, the dongle interprets string data from the host.
	******************************************************************************/

	#include <linux/types.h>
	#include <linux/netdevice.h>

	#include <brcmu_utils.h>
	#include <brcmu_wifi.h>

	#include "dhd.h"
	#include "dhd_proto.h"
	#include "dhd_bus.h"
	#include "fwsignal.h"
	#include "dhd_dbg.h"

	struct brcmf_proto_cdc_dcmd {
	__le32 cmd; /* dongle command value */
	__le32 len; /* lower 16: output buflen;
	* upper 16: input buflen (excludes header) */
	__le32 flags; /* flag defns given below */
	__le32 status; /* status code returned from the device */
	};

	/* Max valid buffer size that can be sent to the dongle */
	#define CDC_MAX_MSG_SIZE (ETH_FRAME_LEN+ETH_FCS_LEN)

	/* CDC flag definitions */
	#define CDC_DCMD_ERROR 0x01 /* 1=cmd failed */
	#define CDC_DCMD_SET 0x02 /* 0=get, 1=set cmd */
	#define CDC_DCMD_IF_MASK 0xF000 /* I/F index */
	#define CDC_DCMD_IF_SHIFT 12
	#define CDC_DCMD_ID_MASK 0xFFFF0000 /* id an cmd pairing */
	#define CDC_DCMD_ID_SHIFT 16 /* ID Mask shift bits */
	#define CDC_DCMD_ID(flags) \
	(((flags) & CDC_DCMD_ID_MASK) >> CDC_DCMD_ID_SHIFT)

	/*
	* BDC header - Broadcom specific extension of CDC.
	* Used on data packets to convey priority across USB.
	*/
	#define BDC_HEADER_LEN 4
	#define BDC_PROTO_VER 2 /* Protocol version */
	#define BDC_FLAG_VER_MASK 0xf0 /* Protocol version mask */
	#define BDC_FLAG_VER_SHIFT 4 /* Protocol version shift */
	#define BDC_FLAG_SUM_GOOD 0x04 /* Good RX checksums */
	#define BDC_FLAG_SUM_NEEDED 0x08 /* Dongle needs to do TX checksums */
	#define BDC_PRIORITY_MASK 0x7
	#define BDC_FLAG2_IF_MASK 0x0f /* packet rx interface in APSTA */
	#define BDC_FLAG2_IF_SHIFT 0

	#define BDC_GET_IF_IDX(hdr) \
	((int)((((hdr)->flags2) & BDC_FLAG2_IF_MASK) >> BDC_FLAG2_IF_SHIFT))
	#define BDC_SET_IF_IDX(hdr, idx) \
	((hdr)->flags2 = (((hdr)->flags2 & ~BDC_FLAG2_IF_MASK) \| \
	((idx) << BDC_FLAG2_IF_SHIFT)))

	/**
	* struct brcmf_proto_bdc_header - BDC header format
	*
	* @flags: flags contain protocol and checksum info.
	* @priority: 802.1d priority and USB flow control info (bit 4:7).
	* @flags2: additional flags containing dongle interface index.
	* @data_offset: start of packet data. header is following by firmware signals.
	*/
	struct brcmf_proto_bdc_header {
	u8 flags;
	u8 priority;
	u8 flags2;
	u8 data_offset;
	};

	/*
	* maximum length of firmware signal data between
	* the BDC header and packet data in the tx path.
	*/
	#define BRCMF_PROT_FW_SIGNAL_MAX_TXBYTES 12

	#define RETRIES 2 /* # of retries to retrieve matching dcmd response */
	#define BUS_HEADER_LEN (16+64) /* Must be atleast SDPCM_RESERVE
	* (amount of header tha might be added)
	* plus any space that might be needed
	* for bus alignment padding.
	*/
	#define ROUND_UP_MARGIN 2048 /* Biggest bus block size possible for
	* round off at the end of buffer
	* Currently is SDIO
	*/

	struct brcmf_proto {
	u16 reqid;
	u8 bus_header[BUS_HEADER_LEN];
	struct brcmf_proto_cdc_dcmd msg;
	unsigned char buf[BRCMF_DCMD_MAXLEN + ROUND_UP_MARGIN];
	};

	static int brcmf_proto_cdc_msg(struct brcmf_pub *drvr)
	{
	struct brcmf_proto *prot = drvr->prot;
	int len = le32_to_cpu(prot->msg.len) +
	sizeof(struct brcmf_proto_cdc_dcmd);

	brcmf_dbg(CDC, "Enter\n");

	/* NOTE : cdc->msg.len holds the desired length of the buffer to be
	* returned. Only up to CDC_MAX_MSG_SIZE of this buffer area
	* is actually sent to the dongle
	*/
	if (len > CDC_MAX_MSG_SIZE)
	len = CDC_MAX_MSG_SIZE;

	/* Send request */
	return brcmf_bus_txctl(drvr->bus_if, (unsigned char *)&prot->msg, len);
	}

	static int brcmf_proto_cdc_cmplt(struct brcmf_pub *drvr, u32 id, u32 len)
	{
	int ret;
	struct brcmf_proto *prot = drvr->prot;

	brcmf_dbg(CDC, "Enter\n");
	len += sizeof(struct brcmf_proto_cdc_dcmd);
	do {
	ret = brcmf_bus_rxctl(drvr->bus_if, (unsigned char *)&prot->msg,
	len);
	if (ret < 0)
	break;
	} while (CDC_DCMD_ID(le32_to_cpu(prot->msg.flags)) != id);

	return ret;
	}

	int
	brcmf_proto_cdc_query_dcmd(struct brcmf_pub *drvr, int ifidx, uint cmd,
	void *buf, uint len)
	{
	struct brcmf_proto *prot = drvr->prot;
	struct brcmf_proto_cdc_dcmd *msg = &prot->msg;
	void *info;
	int ret = 0, retries = 0;
	u32 id, flags;

	brcmf_dbg(CDC, "Enter, cmd %d len %d\n", cmd, len);

	memset(msg, 0, sizeof(struct brcmf_proto_cdc_dcmd));

	msg->cmd = cpu_to_le32(cmd);
	msg->len = cpu_to_le32(len);
	flags = (++prot->reqid << CDC_DCMD_ID_SHIFT);
	flags = (flags & ~CDC_DCMD_IF_MASK) \|
	(ifidx << CDC_DCMD_IF_SHIFT);
	msg->flags = cpu_to_le32(flags);

	if (buf)
	memcpy(prot->buf, buf, len);

	ret = brcmf_proto_cdc_msg(drvr);
	if (ret < 0) {
	brcmf_err("brcmf_proto_cdc_msg failed w/status %d\n",
	ret);
	goto done;
	}

	retry:
	/* wait for interrupt and get first fragment */
	ret = brcmf_proto_cdc_cmplt(drvr, prot->reqid, len);
	if (ret < 0)
	goto done;

	flags = le32_to_cpu(msg->flags);
	id = (flags & CDC_DCMD_ID_MASK) >> CDC_DCMD_ID_SHIFT;

	if ((id < prot->reqid) && (++retries < RETRIES))
	goto retry;
	if (id != prot->reqid) {
	brcmf_err("%s: unexpected request id %d (expected %d)\n",
	brcmf_ifname(drvr, ifidx), id, prot->reqid);
	ret = -EINVAL;
	goto done;
	}

	/* Check info buffer */
	info = (void *)&msg[1];

	/* Copy info buffer */
	if (buf) {
	if (ret < (int)len)
	len = ret;
	memcpy(buf, info, len);
	}

	/* Check the ERROR flag */
	if (flags & CDC_DCMD_ERROR)
	ret = le32_to_cpu(msg->status);

	done:
	return ret;
	}

	int brcmf_proto_cdc_set_dcmd(struct brcmf_pub *drvr, int ifidx, uint cmd,
	void *buf, uint len)
	{
	struct brcmf_proto *prot = drvr->prot;
	struct brcmf_proto_cdc_dcmd *msg = &prot->msg;
	int ret = 0;
	u32 flags, id;

	brcmf_dbg(CDC, "Enter, cmd %d len %d\n", cmd, len);

	memset(msg, 0, sizeof(struct brcmf_proto_cdc_dcmd));

	msg->cmd = cpu_to_le32(cmd);
	msg->len = cpu_to_le32(len);
	flags = (++prot->reqid << CDC_DCMD_ID_SHIFT) \| CDC_DCMD_SET;
	flags = (flags & ~CDC_DCMD_IF_MASK) \|
	(ifidx << CDC_DCMD_IF_SHIFT);
	msg->flags = cpu_to_le32(flags);

	if (buf)
	memcpy(prot->buf, buf, len);

	ret = brcmf_proto_cdc_msg(drvr);
	if (ret < 0)
	goto done;

	ret = brcmf_proto_cdc_cmplt(drvr, prot->reqid, len);
	if (ret < 0)
	goto done;

	flags = le32_to_cpu(msg->flags);
	id = (flags & CDC_DCMD_ID_MASK) >> CDC_DCMD_ID_SHIFT;

	if (id != prot->reqid) {
	brcmf_err("%s: unexpected request id %d (expected %d)\n",
	brcmf_ifname(drvr, ifidx), id, prot->reqid);
	ret = -EINVAL;
	goto done;
	}

	/* Check the ERROR flag */
	if (flags & CDC_DCMD_ERROR)
	ret = le32_to_cpu(msg->status);

	done:
	return ret;
	}

	static bool pkt_sum_needed(struct sk_buff *skb)
	{
	return skb->ip_summed == CHECKSUM_PARTIAL;
	}

	static void pkt_set_sum_good(struct sk_buff *skb, bool x)
	{
	skb->ip_summed = (x ? CHECKSUM_UNNECESSARY : CHECKSUM_NONE);
	}

	void brcmf_proto_hdrpush(struct brcmf_pub *drvr, int ifidx, u8 offset,
	struct sk_buff *pktbuf)
	{
	struct brcmf_proto_bdc_header *h;

	brcmf_dbg(CDC, "Enter\n");

	/* Push BDC header used to convey priority for buses that don't */
	skb_push(pktbuf, BDC_HEADER_LEN);

	h = (struct brcmf_proto_bdc_header *)(pktbuf->data);

	h->flags = (BDC_PROTO_VER << BDC_FLAG_VER_SHIFT);
	if (pkt_sum_needed(pktbuf))
	h->flags \|= BDC_FLAG_SUM_NEEDED;

	h->priority = (pktbuf->priority & BDC_PRIORITY_MASK);
	h->flags2 = 0;
	h->data_offset = offset;
	BDC_SET_IF_IDX(h, ifidx);
	}

	int brcmf_proto_hdrpull(struct brcmf_pub drvr, bool do_fws, u8 ifidx,
	struct sk_buff *pktbuf)
	{
	struct brcmf_proto_bdc_header *h;

	brcmf_dbg(CDC, "Enter\n");

	/* Pop BDC header used to convey priority for buses that don't */

	if (pktbuf->len <= BDC_HEADER_LEN) {
	brcmf_dbg(INFO, "rx data too short (%d <= %d)\n",
	pktbuf->len, BDC_HEADER_LEN);
	return -EBADE;
	}

	h = (struct brcmf_proto_bdc_header *)(pktbuf->data);

	*ifidx = BDC_GET_IF_IDX(h);
	if (*ifidx >= BRCMF_MAX_IFS) {
	brcmf_err("rx data ifnum out of range (%d)\n", *ifidx);
	return -EBADE;
	}
	/* The ifidx is the idx to map to matching netdev/ifp. When receiving
	* events this is easy because it contains the bssidx which maps
	* 1-on-1 to the netdev/ifp. But for data frames the ifidx is rcvd.
	* bssidx 1 is used for p2p0 and no data can be received or
	* transmitted on it. Therefor bssidx is ifidx + 1 if ifidx > 0
	*/
	if (*ifidx)
	(*ifidx)++;

	if (((h->flags & BDC_FLAG_VER_MASK) >> BDC_FLAG_VER_SHIFT) !=
	BDC_PROTO_VER) {
	brcmf_err("%s: non-BDC packet received, flags 0x%x\n",
	brcmf_ifname(drvr, *ifidx), h->flags);
	return -EBADE;
	}

	if (h->flags & BDC_FLAG_SUM_GOOD) {
	brcmf_dbg(CDC, "%s: BDC rcv, good checksum, flags 0x%x\n",
	brcmf_ifname(drvr, *ifidx), h->flags);
	pkt_set_sum_good(pktbuf, true);
	}

	pktbuf->priority = h->priority & BDC_PRIORITY_MASK;

	skb_pull(pktbuf, BDC_HEADER_LEN);
	if (do_fws)
	brcmf_fws_hdrpull(drvr, *ifidx, h->data_offset << 2, pktbuf);
	else
	skb_pull(pktbuf, h->data_offset << 2);

	if (pktbuf->len == 0)
	return -ENODATA;
	return 0;
	}

	int brcmf_proto_attach(struct brcmf_pub *drvr)
	{
	struct brcmf_proto *cdc;

	cdc = kzalloc(sizeof(struct brcmf_proto), GFP_ATOMIC);
	if (!cdc)
	goto fail;

	/* ensure that the msg buf directly follows the cdc msg struct */
	if ((unsigned long)(&cdc->msg + 1) != (unsigned long)cdc->buf) {
	brcmf_err("struct brcmf_proto is not correctly defined\n");
	goto fail;
	}

	drvr->prot = cdc;
	drvr->hdrlen += BDC_HEADER_LEN + BRCMF_PROT_FW_SIGNAL_MAX_TXBYTES;
	drvr->bus_if->maxctl = BRCMF_DCMD_MAXLEN +
	sizeof(struct brcmf_proto_cdc_dcmd) + ROUND_UP_MARGIN;
	return 0;

	fail:
	kfree(cdc);
	return -ENOMEM;
	}

	/* ~NOTE~ What if another thread is waiting on the semaphore? Holding it? */
	void brcmf_proto_detach(struct brcmf_pub *drvr)
	{
	kfree(drvr->prot);
	drvr->prot = NULL;
	}

	void brcmf_proto_stop(struct brcmf_pub *drvr)
	{
	/* Nothing to do for CDC */
	}