dhd_cdc.c

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/*
 * 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.
 ******************************************************************************/

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

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

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

#include "dhd.h"
#include "dhd_proto.h"
#include "dhd_bus.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 {
    u8 flags;
    u8 priority;    /* 802.1d Priority, 4:7 flow control info for usb */
    u8 flags2;
    u8 data_offset;
};


#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 pending;
    u32 lastcmd;
    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(TRACE, "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 drvr->bus_if->brcmf_bus_txctl(drvr->dev,
                         (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(TRACE, "Enter\n");

    do {
        ret = drvr->bus_if->brcmf_bus_rxctl(drvr->dev,
                (unsigned char *)&prot->msg,
                len + sizeof(struct brcmf_proto_cdc_dcmd));
        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(TRACE, "Enter\n");
    brcmf_dbg(CTL, "cmd %d len %d\n", cmd, len);

    /* Respond "bcmerror" and "bcmerrorstr" with local cache */
    if (cmd == BRCMF_C_GET_VAR && buf) {
        if (!strcmp((char *)buf, "bcmerrorstr")) {
            strncpy((char *)buf, "bcm_error",
                BCME_STRLEN);
            goto done;
        } else if (!strcmp((char *)buf, "bcmerror")) {
            *(int *)buf = drvr->dongle_error;
            goto done;
        }
    }

    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_dbg(ERROR, "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_dbg(ERROR, "%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);
        /* Cache error from dongle */
        drvr->dongle_error = ret;
    }

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(TRACE, "Enter\n");
    brcmf_dbg(CTL, "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_dbg(ERROR, "%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);
        /* Cache error from dongle */
        drvr->dongle_error = ret;
    }

done:
    return ret;
}

int
brcmf_proto_dcmd(struct brcmf_pub *drvr, int ifidx, struct brcmf_dcmd *dcmd,
          int len)
{
    struct brcmf_proto *prot = drvr->prot;
    int ret = -1;

    if (drvr->bus_if->state == BRCMF_BUS_DOWN) {
        brcmf_dbg(ERROR, "bus is down. we have nothing to do.\n");
        return ret;
    }
    mutex_lock(&drvr->proto_block);

    brcmf_dbg(TRACE, "Enter\n");

    if (len > BRCMF_DCMD_MAXLEN)
        goto done;

    if (prot->pending == true) {
        brcmf_dbg(TRACE, "CDC packet is pending!!!! cmd=0x%x (%lu) lastcmd=0x%x (%lu)\n",
              dcmd->cmd, (unsigned long)dcmd->cmd, prot->lastcmd,
              (unsigned long)prot->lastcmd);
        if (dcmd->cmd == BRCMF_C_SET_VAR ||
            dcmd->cmd == BRCMF_C_GET_VAR)
            brcmf_dbg(TRACE, "iovar cmd=%s\n", (char *)dcmd->buf);

        goto done;
    }

    prot->pending = true;
    prot->lastcmd = dcmd->cmd;
    if (dcmd->set)
        ret = brcmf_proto_cdc_set_dcmd(drvr, ifidx, dcmd->cmd,
                           dcmd->buf, len);
    else {
        ret = brcmf_proto_cdc_query_dcmd(drvr, ifidx, dcmd->cmd,
                             dcmd->buf, len);
        if (ret > 0)
            dcmd->used = ret -
                    sizeof(struct brcmf_proto_cdc_dcmd);
    }

    if (ret >= 0)
        ret = 0;
    else {
        struct brcmf_proto_cdc_dcmd *msg = &prot->msg;
        /* len == needed when set/query fails from dongle */
        dcmd->needed = le32_to_cpu(msg->len);
    }

    /* Intercept the wme_dp dongle cmd here */
    if (!ret && dcmd->cmd == BRCMF_C_SET_VAR &&
        !strcmp(dcmd->buf, "wme_dp")) {
        int slen;
        __le32 val = 0;

        slen = strlen("wme_dp") + 1;
        if (len >= (int)(slen + sizeof(int)))
            memcpy(&val, (char *)dcmd->buf + slen, sizeof(int));
        drvr->wme_dp = (u8) le32_to_cpu(val);
    }

    prot->pending = false;

done:
    mutex_unlock(&drvr->proto_block);

    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,
             struct sk_buff *pktbuf)
{
    struct brcmf_proto_bdc_header *h;

    brcmf_dbg(TRACE, "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 = 0;
    BDC_SET_IF_IDX(h, ifidx);
}

int brcmf_proto_hdrpull(struct device *dev, int *ifidx,
            struct sk_buff *pktbuf)
{
    struct brcmf_proto_bdc_header *h;
    struct brcmf_bus *bus_if = dev_get_drvdata(dev);
    struct brcmf_pub *drvr = bus_if->drvr;

    brcmf_dbg(TRACE, "Enter\n");

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

    if (pktbuf->len < BDC_HEADER_LEN) {
        brcmf_dbg(ERROR, "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_dbg(ERROR, "rx data ifnum out of range (%d)\n", *ifidx);
        return -EBADE;
    }

    if (((h->flags & BDC_FLAG_VER_MASK) >> BDC_FLAG_VER_SHIFT) !=
        BDC_PROTO_VER) {
        brcmf_dbg(ERROR, "%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(INFO, "%s: BDC packet received with good rx-csum, 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);
    skb_pull(pktbuf, h->data_offset << 2);

    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_dbg(ERROR, "struct brcmf_proto is not correctly defined\n");
        goto fail;
    }

    drvr->prot = cdc;
    drvr->hdrlen += BDC_HEADER_LEN;
    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;
}

int brcmf_proto_init(struct brcmf_pub *drvr)
{
    int ret = 0;
    char buf[128];

    brcmf_dbg(TRACE, "Enter\n");

    mutex_lock(&drvr->proto_block);

    /* Get the device MAC address */
    strcpy(buf, "cur_etheraddr");
    ret = brcmf_proto_cdc_query_dcmd(drvr, 0, BRCMF_C_GET_VAR,
                      buf, sizeof(buf));
    if (ret < 0) {
        mutex_unlock(&drvr->proto_block);
        return ret;
    }
    memcpy(drvr->mac, buf, ETH_ALEN);

    mutex_unlock(&drvr->proto_block);

    ret = brcmf_c_preinit_dcmds(drvr);

    /* Always assumes wl for now */
    drvr->iswl = true;

    return ret;
}

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