Merge branch 'ext3-latency-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git...

[linux-2.6] / drivers / net / wimax / i2400m / control.c

/*
 * Intel Wireless WiMAX Connection 2400m
 * Miscellaneous control functions for managing the device
 *
 *
 * Copyright (C) 2007-2008 Intel Corporation. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in
 *     the documentation and/or other materials provided with the
 *     distribution.
 *   * Neither the name of Intel Corporation nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 *
 * Intel Corporation <linux-wimax@intel.com>
 * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
 *  - Initial implementation
 *
 * This is a collection of functions used to control the device (plus
 * a few helpers).
 *
 * There are utilities for handling TLV buffers, hooks on the device's
 * reports to act on device changes of state [i2400m_report_hook()],
 * on acks to commands [i2400m_msg_ack_hook()], a helper for sending
 * commands to the device and blocking until a reply arrives
 * [i2400m_msg_to_dev()], a few high level commands for manipulating
 * the device state, powersving mode and configuration plus the
 * routines to setup the device once communication is stablished with
 * it [i2400m_dev_initialize()].
 *
 * ROADMAP
 *
 * i2400m_dev_initalize()       Called by i2400m_dev_start()
 *   i2400m_set_init_config()
 *   i2400m_cmd_get_state()
 * i2400m_dev_shutdown()        Called by i2400m_dev_stop()
 *   i2400m->bus_reset()
 *
 * i2400m_{cmd,get,set}_*()
 *   i2400m_msg_to_dev()
 *   i2400m_msg_check_status()
 *
 * i2400m_report_hook()         Called on reception of an event
 *   i2400m_report_state_hook()
 *     i2400m_tlv_buffer_walk()
 *     i2400m_tlv_match()
 *     i2400m_report_tlv_system_state()
 *     i2400m_report_tlv_rf_switches_status()
 *     i2400m_report_tlv_media_status()
 *   i2400m_cmd_enter_powersave()
 *
 * i2400m_msg_ack_hook()        Called on reception of a reply to a
 *                              command, get or set
 */

#include <stdarg.h>
#include "i2400m.h"
#include <linux/kernel.h>
#include <linux/wimax/i2400m.h>


#define D_SUBMODULE control
#include "debug-levels.h"


/*
 * Return if a TLV is of a give type and size
 *
 * @tlv_hdr: pointer to the TLV
 * @tlv_type: type of the TLV we are looking for
 * @tlv_size: expected size of the TLV we are looking for (if -1,
 *            don't check the size). This includes the header
 * Returns: 0 if the TLV matches
 *          < 0 if it doesn't match at all
 *          > 0 total TLV + payload size, if the type matches, but not
 *              the size
 */
static
ssize_t i2400m_tlv_match(const struct i2400m_tlv_hdr *tlv,
                     enum i2400m_tlv tlv_type, ssize_t tlv_size)
{
        if (le16_to_cpu(tlv->type) != tlv_type) /* Not our type? skip */
                return -1;
        if (tlv_size != -1
            && le16_to_cpu(tlv->length) + sizeof(*tlv) != tlv_size) {
                size_t size = le16_to_cpu(tlv->length) + sizeof(*tlv);
                printk(KERN_WARNING "W: tlv type 0x%x mismatched because of "
                       "size (got %zu vs %zu expected)\n",
                       tlv_type, size, tlv_size);
                return size;
        }
        return 0;
}


/*
 * Given a buffer of TLVs, iterate over them
 *
 * @i2400m: device instance
 * @tlv_buf: pointer to the beginning of the TLV buffer
 * @buf_size: buffer size in bytes
 * @tlv_pos: seek position; this is assumed to be a pointer returned
 *           by i2400m_tlv_buffer_walk() [and thus, validated]. The
 *           TLV returned will be the one following this one.
 *
 * Usage:
 *
 * tlv_itr = NULL;
 * while (tlv_itr = i2400m_tlv_buffer_walk(i2400m, buf, size, tlv_itr))  {
 *         ...
 *         // Do stuff with tlv_itr, DON'T MODIFY IT
 *         ...
 * }
 */
static
const struct i2400m_tlv_hdr *i2400m_tlv_buffer_walk(
        struct i2400m *i2400m,
        const void *tlv_buf, size_t buf_size,
        const struct i2400m_tlv_hdr *tlv_pos)
{
        struct device *dev = i2400m_dev(i2400m);
        const struct i2400m_tlv_hdr *tlv_top = tlv_buf + buf_size;
        size_t offset, length, avail_size;
        unsigned type;

        if (tlv_pos == NULL)    /* Take the first one? */
                tlv_pos = tlv_buf;
        else                    /* Nope, the next one */
                tlv_pos = (void *) tlv_pos
                        + le16_to_cpu(tlv_pos->length) + sizeof(*tlv_pos);
        if (tlv_pos == tlv_top) {       /* buffer done */
                tlv_pos = NULL;
                goto error_beyond_end;
        }
        if (tlv_pos > tlv_top) {
                tlv_pos = NULL;
                WARN_ON(1);
                goto error_beyond_end;
        }
        offset = (void *) tlv_pos - (void *) tlv_buf;
        avail_size = buf_size - offset;
        if (avail_size < sizeof(*tlv_pos)) {
                dev_err(dev, "HW BUG? tlv_buf %p [%zu bytes], tlv @%zu: "
                        "short header\n", tlv_buf, buf_size, offset);
                goto error_short_header;
        }
        type = le16_to_cpu(tlv_pos->type);
        length = le16_to_cpu(tlv_pos->length);
        if (avail_size < sizeof(*tlv_pos) + length) {
                dev_err(dev, "HW BUG? tlv_buf %p [%zu bytes], "
                        "tlv type 0x%04x @%zu: "
                        "short data (%zu bytes vs %zu needed)\n",
                        tlv_buf, buf_size, type, offset, avail_size,
                        sizeof(*tlv_pos) + length);
                goto error_short_header;
        }
error_short_header:
error_beyond_end:
        return tlv_pos;
}


/*
 * Find a TLV in a buffer of sequential TLVs
 *
 * @i2400m: device descriptor
 * @tlv_hdr: pointer to the first TLV in the sequence
 * @size: size of the buffer in bytes; all TLVs are assumed to fit
 *        fully in the buffer (otherwise we'll complain).
 * @tlv_type: type of the TLV we are looking for
 * @tlv_size: expected size of the TLV we are looking for (if -1,
 *            don't check the size). This includes the header
 *
 * Returns: NULL if the TLV is not found, otherwise a pointer to
 *          it. If the sizes don't match, an error is printed and NULL
 *          returned.
 */
static
const struct i2400m_tlv_hdr *i2400m_tlv_find(
        struct i2400m *i2400m,
        const struct i2400m_tlv_hdr *tlv_hdr, size_t size,
        enum i2400m_tlv tlv_type, ssize_t tlv_size)
{
        ssize_t match;
        struct device *dev = i2400m_dev(i2400m);
        const struct i2400m_tlv_hdr *tlv = NULL;
        while ((tlv = i2400m_tlv_buffer_walk(i2400m, tlv_hdr, size, tlv))) {
                match = i2400m_tlv_match(tlv, tlv_type, tlv_size);
                if (match == 0)         /* found it :) */
                        break;
                if (match > 0)
                        dev_warn(dev, "TLV type 0x%04x found with size "
                                 "mismatch (%zu vs %zu needed)\n",
                                 tlv_type, match, tlv_size);
        }
        return tlv;
}


static const struct
{
        char *msg;
        int errno;
} ms_to_errno[I2400M_MS_MAX] = {
        [I2400M_MS_DONE_OK] = { "", 0 },
        [I2400M_MS_DONE_IN_PROGRESS] = { "", 0 },
        [I2400M_MS_INVALID_OP] = { "invalid opcode", -ENOSYS },
        [I2400M_MS_BAD_STATE] = { "invalid state", -EILSEQ },
        [I2400M_MS_ILLEGAL_VALUE] = { "illegal value", -EINVAL },
        [I2400M_MS_MISSING_PARAMS] = { "missing parameters", -ENOMSG },
        [I2400M_MS_VERSION_ERROR] = { "bad version", -EIO },
        [I2400M_MS_ACCESSIBILITY_ERROR] = { "accesibility error", -EIO },
        [I2400M_MS_BUSY] = { "busy", -EBUSY },
        [I2400M_MS_CORRUPTED_TLV] = { "corrupted TLV", -EILSEQ },
        [I2400M_MS_UNINITIALIZED] = { "not unitialized", -EILSEQ },
        [I2400M_MS_UNKNOWN_ERROR] = { "unknown error", -EIO },
        [I2400M_MS_PRODUCTION_ERROR] = { "production error", -EIO },
        [I2400M_MS_NO_RF] = { "no RF", -EIO },
        [I2400M_MS_NOT_READY_FOR_POWERSAVE] =
                { "not ready for powersave", -EACCES },
        [I2400M_MS_THERMAL_CRITICAL] = { "thermal critical", -EL3HLT },
};


/*
 * i2400m_msg_check_status - translate a message's status code
 *
 * @i2400m: device descriptor
 * @l3l4_hdr: message header
 * @strbuf: buffer to place a formatted error message (unless NULL).
 * @strbuf_size: max amount of available space; larger messages will
 * be truncated.
 *
 * Returns: errno code corresponding to the status code in @l3l4_hdr
 *          and a message in @strbuf describing the error.
 */
int i2400m_msg_check_status(const struct i2400m_l3l4_hdr *l3l4_hdr,
                            char *strbuf, size_t strbuf_size)
{
        int result;
        enum i2400m_ms status = le16_to_cpu(l3l4_hdr->status);
        const char *str;

        if (status == 0)
                return 0;
        if (status > ARRAY_SIZE(ms_to_errno)) {
                str = "unknown status code";
                result = -EBADR;
        } else {
                str = ms_to_errno[status].msg;
                result = ms_to_errno[status].errno;
        }
        if (strbuf)
                snprintf(strbuf, strbuf_size, "%s (%d)", str, status);
        return result;
}


/*
 * Act on a TLV System State reported by the device
 *
 * @i2400m: device descriptor
 * @ss: validated System State TLV
 */
static
void i2400m_report_tlv_system_state(struct i2400m *i2400m,
                                    const struct i2400m_tlv_system_state *ss)
{
        struct device *dev = i2400m_dev(i2400m);
        struct wimax_dev *wimax_dev = &i2400m->wimax_dev;
        enum i2400m_system_state i2400m_state = le32_to_cpu(ss->state);

        d_fnstart(3, dev, "(i2400m %p ss %p [%u])\n", i2400m, ss, i2400m_state);

        if (unlikely(i2400m->ready == 0))       /* act if up */
                goto out;
        if (i2400m->state != i2400m_state) {
                i2400m->state = i2400m_state;
                wake_up_all(&i2400m->state_wq);
        }
        switch (i2400m_state) {
        case I2400M_SS_UNINITIALIZED:
        case I2400M_SS_INIT:
        case I2400M_SS_CONFIG:
        case I2400M_SS_PRODUCTION:
                wimax_state_change(wimax_dev, WIMAX_ST_UNINITIALIZED);
                break;

        case I2400M_SS_RF_OFF:
        case I2400M_SS_RF_SHUTDOWN:
                wimax_state_change(wimax_dev, WIMAX_ST_RADIO_OFF);
                break;

        case I2400M_SS_READY:
        case I2400M_SS_STANDBY:
        case I2400M_SS_SLEEPACTIVE:
                wimax_state_change(wimax_dev, WIMAX_ST_READY);
                break;

        case I2400M_SS_CONNECTING:
        case I2400M_SS_WIMAX_CONNECTED:
                wimax_state_change(wimax_dev, WIMAX_ST_READY);
                break;

        case I2400M_SS_SCAN:
        case I2400M_SS_OUT_OF_ZONE:
                wimax_state_change(wimax_dev, WIMAX_ST_SCANNING);
                break;

        case I2400M_SS_IDLE:
                d_printf(1, dev, "entering BS-negotiated idle mode\n");
        case I2400M_SS_DISCONNECTING:
        case I2400M_SS_DATA_PATH_CONNECTED:
                wimax_state_change(wimax_dev, WIMAX_ST_CONNECTED);
                break;

        default:
                /* Huh? just in case, shut it down */
                dev_err(dev, "HW BUG? unknown state %u: shutting down\n",
                        i2400m_state);
                i2400m->bus_reset(i2400m, I2400M_RT_WARM);
                break;
        };
out:
        d_fnend(3, dev, "(i2400m %p ss %p [%u]) = void\n",
                i2400m, ss, i2400m_state);
}


/*
 * Parse and act on a TLV Media Status sent by the device
 *
 * @i2400m: device descriptor
 * @ms: validated Media Status TLV
 *
 * This will set the carrier up on down based on the device's link
 * report. This is done asides of what the WiMAX stack does based on
 * the device's state as sometimes we need to do a link-renew (the BS
 * wants us to renew a DHCP lease, for example).
 *
 * In fact, doc says that everytime we get a link-up, we should do a
 * DHCP negotiation...
 */
static
void i2400m_report_tlv_media_status(struct i2400m *i2400m,
                                    const struct i2400m_tlv_media_status *ms)
{
        struct device *dev = i2400m_dev(i2400m);
        struct wimax_dev *wimax_dev = &i2400m->wimax_dev;
        struct net_device *net_dev = wimax_dev->net_dev;
        enum i2400m_media_status status = le32_to_cpu(ms->media_status);

        d_fnstart(3, dev, "(i2400m %p ms %p [%u])\n", i2400m, ms, status);

        if (unlikely(i2400m->ready == 0))       /* act if up */
                goto out;
        switch (status) {
        case I2400M_MEDIA_STATUS_LINK_UP:
                netif_carrier_on(net_dev);
                break;
        case I2400M_MEDIA_STATUS_LINK_DOWN:
                netif_carrier_off(net_dev);
                break;
        /*
         * This is the network telling us we need to retrain the DHCP
         * lease -- so far, we are trusting the WiMAX Network Service
         * in user space to pick this up and poke the DHCP client.
         */
        case I2400M_MEDIA_STATUS_LINK_RENEW:
                netif_carrier_on(net_dev);
                break;
        default:
                dev_err(dev, "HW BUG? unknown media status %u\n",
                        status);
        };
out:
        d_fnend(3, dev, "(i2400m %p ms %p [%u]) = void\n",
                i2400m, ms, status);
}


/*
 * Parse a 'state report' and extract carrier on/off information
 *
 * @i2400m: device descriptor
 * @l3l4_hdr: pointer to message; it has been already validated for
 *            consistent size.
 * @size: size of the message (header + payload). The header length
 *        declaration is assumed to be congruent with @size (as in
 *        sizeof(*l3l4_hdr) + l3l4_hdr->length == size)
 *
 * Extract from the report state the system state TLV and infer from
 * there if we have a carrier or not. Update our local state and tell
 * netdev.
 *
 * When setting the carrier, it's fine to set OFF twice (for example),
 * as netif_carrier_off() will not generate two OFF events (just on
 * the transitions).
 */
static
void i2400m_report_state_hook(struct i2400m *i2400m,
                              const struct i2400m_l3l4_hdr *l3l4_hdr,
                              size_t size, const char *tag)
{
        struct device *dev = i2400m_dev(i2400m);
        const struct i2400m_tlv_hdr *tlv;
        const struct i2400m_tlv_system_state *ss;
        const struct i2400m_tlv_rf_switches_status *rfss;
        const struct i2400m_tlv_media_status *ms;
        size_t tlv_size = le16_to_cpu(l3l4_hdr->length);

        d_fnstart(4, dev, "(i2400m %p, l3l4_hdr %p, size %zu, %s)\n",
                  i2400m, l3l4_hdr, size, tag);
        tlv = NULL;

        while ((tlv = i2400m_tlv_buffer_walk(i2400m, &l3l4_hdr->pl,
                                             tlv_size, tlv))) {
                if (0 == i2400m_tlv_match(tlv, I2400M_TLV_SYSTEM_STATE,
                                          sizeof(*ss))) {
                        ss = container_of(tlv, typeof(*ss), hdr);
                        d_printf(2, dev, "%s: system state TLV "
                                 "found (0x%04x), state 0x%08x\n",
                                 tag, I2400M_TLV_SYSTEM_STATE,
                                 le32_to_cpu(ss->state));
                        i2400m_report_tlv_system_state(i2400m, ss);
                }
                if (0 == i2400m_tlv_match(tlv, I2400M_TLV_RF_STATUS,
                                          sizeof(*rfss))) {
                        rfss = container_of(tlv, typeof(*rfss), hdr);
                        d_printf(2, dev, "%s: RF status TLV "
                                 "found (0x%04x), sw 0x%02x hw 0x%02x\n",
                                 tag, I2400M_TLV_RF_STATUS,
                                 le32_to_cpu(rfss->sw_rf_switch),
                                 le32_to_cpu(rfss->hw_rf_switch));
                        i2400m_report_tlv_rf_switches_status(i2400m, rfss);
                }
                if (0 == i2400m_tlv_match(tlv, I2400M_TLV_MEDIA_STATUS,
                                          sizeof(*ms))) {
                        ms = container_of(tlv, typeof(*ms), hdr);
                        d_printf(2, dev, "%s: Media Status TLV: %u\n",
                                 tag, le32_to_cpu(ms->media_status));
                        i2400m_report_tlv_media_status(i2400m, ms);
                }
        }
        d_fnend(4, dev, "(i2400m %p, l3l4_hdr %p, size %zu, %s) = void\n",
                i2400m, l3l4_hdr, size, tag);
}


/*
 * i2400m_report_hook - (maybe) act on a report
 *
 * @i2400m: device descriptor
 * @l3l4_hdr: pointer to message; it has been already validated for
 *            consistent size.
 * @size: size of the message (header + payload). The header length
 *        declaration is assumed to be congruent with @size (as in
 *        sizeof(*l3l4_hdr) + l3l4_hdr->length == size)
 *
 * Extract information we might need (like carrien on/off) from a
 * device report.
 */
void i2400m_report_hook(struct i2400m *i2400m,
                        const struct i2400m_l3l4_hdr *l3l4_hdr, size_t size)
{
        struct device *dev = i2400m_dev(i2400m);
        unsigned msg_type;

        d_fnstart(3, dev, "(i2400m %p l3l4_hdr %p size %zu)\n",
                  i2400m, l3l4_hdr, size);
        /* Chew on the message, we might need some information from
         * here */
        msg_type = le16_to_cpu(l3l4_hdr->type);
        switch (msg_type) {
        case I2400M_MT_REPORT_STATE:    /* carrier detection... */
                i2400m_report_state_hook(i2400m,
                                         l3l4_hdr, size, "REPORT STATE");
                break;
        /* If the device is ready for power save, then ask it to do
         * it. */
        case I2400M_MT_REPORT_POWERSAVE_READY:  /* zzzzz */
                if (l3l4_hdr->status == cpu_to_le16(I2400M_MS_DONE_OK)) {
                        d_printf(1, dev, "ready for powersave, requesting\n");
                        i2400m_cmd_enter_powersave(i2400m);
                }
                break;
        };
        d_fnend(3, dev, "(i2400m %p l3l4_hdr %p size %zu) = void\n",
                i2400m, l3l4_hdr, size);
}


/*
 * i2400m_msg_ack_hook - process cmd/set/get ack for internal status
 *
 * @i2400m: device descriptor
 * @l3l4_hdr: pointer to message; it has been already validated for
 *            consistent size.
 * @size: size of the message
 *
 * Extract information we might need from acks to commands and act on
 * it. This is akin to i2400m_report_hook(). Note most of this
 * processing should be done in the function that calls the
 * command. This is here for some cases where it can't happen...
 */
void i2400m_msg_ack_hook(struct i2400m *i2400m,
                         const struct i2400m_l3l4_hdr *l3l4_hdr, size_t size)
{
        int result;
        struct device *dev = i2400m_dev(i2400m);
        unsigned ack_type, ack_status;
        char strerr[32];

        /* Chew on the message, we might need some information from
         * here */
        ack_type = le16_to_cpu(l3l4_hdr->type);
        ack_status = le16_to_cpu(l3l4_hdr->status);
        switch (ack_type) {
        case I2400M_MT_CMD_ENTER_POWERSAVE:
                /* This is just left here for the sake of example, as
                 * the processing is done somewhere else. */
                if (0) {
                        result = i2400m_msg_check_status(
                                l3l4_hdr, strerr, sizeof(strerr));
                        if (result >= 0)
                                d_printf(1, dev, "ready for power save: %zd\n",
                                         size);
                }
                break;
        };
        return;
}


/*
 * i2400m_msg_size_check() - verify message size and header are congruent
 *
 * It is ok if the total message size is larger than the expected
 * size, as there can be padding.
 */
int i2400m_msg_size_check(struct i2400m *i2400m,
                          const struct i2400m_l3l4_hdr *l3l4_hdr,
                          size_t msg_size)
{
        int result;
        struct device *dev = i2400m_dev(i2400m);
        size_t expected_size;
        d_fnstart(4, dev, "(i2400m %p l3l4_hdr %p msg_size %zu)\n",
                  i2400m, l3l4_hdr, msg_size);
        if (msg_size < sizeof(*l3l4_hdr)) {
                dev_err(dev, "bad size for message header "
                        "(expected at least %zu, got %zu)\n",
                        (size_t) sizeof(*l3l4_hdr), msg_size);
                result = -EIO;
                goto error_hdr_size;
        }
        expected_size = le16_to_cpu(l3l4_hdr->length) + sizeof(*l3l4_hdr);
        if (msg_size < expected_size) {
                dev_err(dev, "bad size for message code 0x%04x (expected %zu, "
                        "got %zu)\n", le16_to_cpu(l3l4_hdr->type),
                        expected_size, msg_size);
                result = -EIO;
        } else
                result = 0;
error_hdr_size:
        d_fnend(4, dev,
                "(i2400m %p l3l4_hdr %p msg_size %zu) = %d\n",
                i2400m, l3l4_hdr, msg_size, result);
        return result;
}



/*
 * Cancel a wait for a command ACK
 *
 * @i2400m: device descriptor
 * @code: [negative] errno code to cancel with (don't use
 *     -EINPROGRESS)
 *
 * If there is an ack already filled out, free it.
 */
void i2400m_msg_to_dev_cancel_wait(struct i2400m *i2400m, int code)
{
        struct sk_buff *ack_skb;
        unsigned long flags;

        spin_lock_irqsave(&i2400m->rx_lock, flags);
        ack_skb = i2400m->ack_skb;
        if (ack_skb && !IS_ERR(ack_skb))
                kfree_skb(ack_skb);
        i2400m->ack_skb = ERR_PTR(code);
        spin_unlock_irqrestore(&i2400m->rx_lock, flags);
}


/**
 * i2400m_msg_to_dev - Send a control message to the device and get a response
 *
 * @i2400m: device descriptor
 *
 * @msg_skb: an skb  *
 *
 * @buf: pointer to the buffer containing the message to be sent; it
 *           has to start with a &struct i2400M_l3l4_hdr and then
 *           followed by the payload. Once this function returns, the
 *           buffer can be reused.
 *
 * @buf_len: buffer size
 *
 * Returns:
 *
 * Pointer to skb containing the ack message. You need to check the
 * pointer with IS_ERR(), as it might be an error code. Error codes
 * could happen because:
 *
 *  - the message wasn't formatted correctly
 *  - couldn't send the message
 *  - failed waiting for a response
 *  - the ack message wasn't formatted correctly
 *
 * The returned skb has been allocated with wimax_msg_to_user_alloc(),
 * it contains the reponse in a netlink attribute and is ready to be
 * passed up to user space with wimax_msg_to_user_send(). To access
 * the payload and its length, use wimax_msg_{data,len}() on the skb.
 *
 * The skb has to be freed with kfree_skb() once done.
 *
 * Description:
 *
 * This function delivers a message/command to the device and waits
 * for an ack to be received. The format is described in
 * linux/wimax/i2400m.h. In summary, a command/get/set is followed by an
 * ack.
 *
 * This function will not check the ack status, that's left up to the
 * caller.  Once done with the ack skb, it has to be kfree_skb()ed.
 *
 * The i2400m handles only one message at the same time, thus we need
 * the mutex to exclude other players.
 *
 * We write the message and then wait for an answer to come back. The
 * RX path intercepts control messages and handles them in
 * i2400m_rx_ctl(). Reports (notifications) are (maybe) processed
 * locally and then forwarded (as needed) to user space on the WiMAX
 * stack message pipe. Acks are saved and passed back to us through an
 * skb in i2400m->ack_skb which is ready to be given to generic
 * netlink if need be.
 */
struct sk_buff *i2400m_msg_to_dev(struct i2400m *i2400m,
                                  const void *buf, size_t buf_len)
{
        int result;
        struct device *dev = i2400m_dev(i2400m);
        const struct i2400m_l3l4_hdr *msg_l3l4_hdr;
        struct sk_buff *ack_skb;
        const struct i2400m_l3l4_hdr *ack_l3l4_hdr;
        size_t ack_len;
        int ack_timeout;
        unsigned msg_type;
        unsigned long flags;

        d_fnstart(3, dev, "(i2400m %p buf %p len %zu)\n",
                  i2400m, buf, buf_len);

        if (i2400m->boot_mode)
                return ERR_PTR(-ENODEV);

        msg_l3l4_hdr = buf;
        /* Check msg & payload consistency */
        result = i2400m_msg_size_check(i2400m, msg_l3l4_hdr, buf_len);
        if (result < 0)
                goto error_bad_msg;
        msg_type = le16_to_cpu(msg_l3l4_hdr->type);
        d_printf(1, dev, "CMD/GET/SET 0x%04x %zu bytes\n",
                 msg_type, buf_len);
        d_dump(2, dev, buf, buf_len);

        /* Setup the completion, ack_skb ("we are waiting") and send
         * the message to the device */
        mutex_lock(&i2400m->msg_mutex);
        spin_lock_irqsave(&i2400m->rx_lock, flags);
        i2400m->ack_skb = ERR_PTR(-EINPROGRESS);
        spin_unlock_irqrestore(&i2400m->rx_lock, flags);
        init_completion(&i2400m->msg_completion);
        result = i2400m_tx(i2400m, buf, buf_len, I2400M_PT_CTRL);
        if (result < 0) {
                dev_err(dev, "can't send message 0x%04x: %d\n",
                        le16_to_cpu(msg_l3l4_hdr->type), result);
                goto error_tx;
        }

        /* Some commands take longer to execute because of crypto ops,
         * so we give them some more leeway on timeout */
        switch (msg_type) {
        case I2400M_MT_GET_TLS_OPERATION_RESULT:
        case I2400M_MT_CMD_SEND_EAP_RESPONSE:
                ack_timeout = 5 * HZ;
                break;
        default:
                ack_timeout = HZ;
        };

        /* The RX path in rx.c will put any response for this message
         * in i2400m->ack_skb and wake us up. If we cancel the wait,
         * we need to change the value of i2400m->ack_skb to something
         * not -EINPROGRESS so RX knows there is no one waiting. */
        result = wait_for_completion_interruptible_timeout(
                &i2400m->msg_completion, ack_timeout);
        if (result == 0) {
                dev_err(dev, "timeout waiting for reply to message 0x%04x\n",
                        msg_type);
                result = -ETIMEDOUT;
                i2400m_msg_to_dev_cancel_wait(i2400m, result);
                goto error_wait_for_completion;
        } else if (result < 0) {
                dev_err(dev, "error waiting for reply to message 0x%04x: %d\n",
                        msg_type, result);
                i2400m_msg_to_dev_cancel_wait(i2400m, result);
                goto error_wait_for_completion;
        }

        /* Pull out the ack data from i2400m->ack_skb -- see if it is
         * an error and act accordingly */
        spin_lock_irqsave(&i2400m->rx_lock, flags);
        ack_skb = i2400m->ack_skb;
        if (IS_ERR(ack_skb))
                result = PTR_ERR(ack_skb);
        else
                result = 0;
        i2400m->ack_skb = NULL;
        spin_unlock_irqrestore(&i2400m->rx_lock, flags);
        if (result < 0)
                goto error_ack_status;
        ack_l3l4_hdr = wimax_msg_data_len(ack_skb, &ack_len);

        /* Check the ack and deliver it if it is ok */
        result = i2400m_msg_size_check(i2400m, ack_l3l4_hdr, ack_len);
        if (result < 0) {
                dev_err(dev, "HW BUG? reply to message 0x%04x: %d\n",
                        msg_type, result);
                goto error_bad_ack_len;
        }
        if (msg_type != le16_to_cpu(ack_l3l4_hdr->type)) {
                dev_err(dev, "HW BUG? bad reply 0x%04x to message 0x%04x\n",
                        le16_to_cpu(ack_l3l4_hdr->type), msg_type);
                result = -EIO;
                goto error_bad_ack_type;
        }
        i2400m_msg_ack_hook(i2400m, ack_l3l4_hdr, ack_len);
        mutex_unlock(&i2400m->msg_mutex);
        d_fnend(3, dev, "(i2400m %p buf %p len %zu) = %p\n",
                i2400m, buf, buf_len, ack_skb);
        return ack_skb;

error_bad_ack_type:
error_bad_ack_len:
        kfree_skb(ack_skb);
error_ack_status:
error_wait_for_completion:
error_tx:
        mutex_unlock(&i2400m->msg_mutex);
error_bad_msg:
        d_fnend(3, dev, "(i2400m %p buf %p len %zu) = %d\n",
                i2400m, buf, buf_len, result);
        return ERR_PTR(result);
}


/*
 * Definitions for the Enter Power Save command
 *
 * The Enter Power Save command requests the device to go into power
 * saving mode. The device will ack or nak the command depending on it
 * being ready for it. If it acks, we tell the USB subsystem to
 *
 * As well, the device might request to go into power saving mode by
 * sending a report (REPORT_POWERSAVE_READY), in which case, we issue
 * this command. The hookups in the RX coder allow
 */
enum {
        I2400M_WAKEUP_ENABLED  = 0x01,
        I2400M_WAKEUP_DISABLED = 0x02,
        I2400M_TLV_TYPE_WAKEUP_MODE = 144,
};

struct i2400m_cmd_enter_power_save {
        struct i2400m_l3l4_hdr hdr;
        struct i2400m_tlv_hdr tlv;
        __le32 val;
} __attribute__((packed));


/*
 * Request entering power save
 *
 * This command is (mainly) executed when the device indicates that it
 * is ready to go into powersave mode via a REPORT_POWERSAVE_READY.
 */
int i2400m_cmd_enter_powersave(struct i2400m *i2400m)
{
        int result;
        struct device *dev = i2400m_dev(i2400m);
        struct sk_buff *ack_skb;
        struct i2400m_cmd_enter_power_save *cmd;
        char strerr[32];

        result = -ENOMEM;
        cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
        if (cmd == NULL)
                goto error_alloc;
        cmd->hdr.type = cpu_to_le16(I2400M_MT_CMD_ENTER_POWERSAVE);
        cmd->hdr.length = cpu_to_le16(sizeof(*cmd) - sizeof(cmd->hdr));
        cmd->hdr.version = cpu_to_le16(I2400M_L3L4_VERSION);
        cmd->tlv.type = cpu_to_le16(I2400M_TLV_TYPE_WAKEUP_MODE);
        cmd->tlv.length = cpu_to_le16(sizeof(cmd->val));
        cmd->val = cpu_to_le32(I2400M_WAKEUP_ENABLED);

        ack_skb = i2400m_msg_to_dev(i2400m, cmd, sizeof(*cmd));
        result = PTR_ERR(ack_skb);
        if (IS_ERR(ack_skb)) {
                dev_err(dev, "Failed to issue 'Enter power save' command: %d\n",
                        result);
                goto error_msg_to_dev;
        }
        result = i2400m_msg_check_status(wimax_msg_data(ack_skb),
                                         strerr, sizeof(strerr));
        if (result == -EACCES)
                d_printf(1, dev, "Cannot enter power save mode\n");
        else if (result < 0)
                dev_err(dev, "'Enter power save' (0x%04x) command failed: "
                        "%d - %s\n", I2400M_MT_CMD_ENTER_POWERSAVE,
                        result, strerr);
        else
                d_printf(1, dev, "device ready to power save\n");
        kfree_skb(ack_skb);
error_msg_to_dev:
        kfree(cmd);
error_alloc:
        return result;
}
EXPORT_SYMBOL_GPL(i2400m_cmd_enter_powersave);


/*
 * Definitions for getting device information
 */
enum {
        I2400M_TLV_DETAILED_DEVICE_INFO = 140
};

/**
 * i2400m_get_device_info - Query the device for detailed device information
 *
 * @i2400m: device descriptor
 *
 * Returns: an skb whose skb->data points to a 'struct
 *    i2400m_tlv_detailed_device_info'. When done, kfree_skb() it. The
 *    skb is *guaranteed* to contain the whole TLV data structure.
 *
 *    On error, IS_ERR(skb) is true and ERR_PTR(skb) is the error
 *    code.
 */
struct sk_buff *i2400m_get_device_info(struct i2400m *i2400m)
{
        int result;
        struct device *dev = i2400m_dev(i2400m);
        struct sk_buff *ack_skb;
        struct i2400m_l3l4_hdr *cmd;
        const struct i2400m_l3l4_hdr *ack;
        size_t ack_len;
        const struct i2400m_tlv_hdr *tlv;
        const struct i2400m_tlv_detailed_device_info *ddi;
        char strerr[32];

        ack_skb = ERR_PTR(-ENOMEM);
        cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
        if (cmd == NULL)
                goto error_alloc;
        cmd->type = cpu_to_le16(I2400M_MT_GET_DEVICE_INFO);
        cmd->length = 0;
        cmd->version = cpu_to_le16(I2400M_L3L4_VERSION);

        ack_skb = i2400m_msg_to_dev(i2400m, cmd, sizeof(*cmd));
        if (IS_ERR(ack_skb)) {
                dev_err(dev, "Failed to issue 'get device info' command: %ld\n",
                        PTR_ERR(ack_skb));
                goto error_msg_to_dev;
        }
        ack = wimax_msg_data_len(ack_skb, &ack_len);
        result = i2400m_msg_check_status(ack, strerr, sizeof(strerr));
        if (result < 0) {
                dev_err(dev, "'get device info' (0x%04x) command failed: "
                        "%d - %s\n", I2400M_MT_GET_DEVICE_INFO, result,
                        strerr);
                goto error_cmd_failed;
        }
        tlv = i2400m_tlv_find(i2400m, ack->pl, ack_len - sizeof(*ack),
                              I2400M_TLV_DETAILED_DEVICE_INFO, sizeof(*ddi));
        if (tlv == NULL) {
                dev_err(dev, "GET DEVICE INFO: "
                        "detailed device info TLV not found (0x%04x)\n",
                        I2400M_TLV_DETAILED_DEVICE_INFO);
                result = -EIO;
                goto error_no_tlv;
        }
        skb_pull(ack_skb, (void *) tlv - (void *) ack_skb->data);
error_msg_to_dev:
        kfree(cmd);
error_alloc:
        return ack_skb;

error_no_tlv:
error_cmd_failed:
        kfree_skb(ack_skb);
        kfree(cmd);
        return ERR_PTR(result);
}


/* Firmware interface versions we support */
enum {
        I2400M_HDIv_MAJOR = 9,
        I2400M_HDIv_MINOR = 1,
        I2400M_HDIv_MINOR_2 = 2,
};


/**
 * i2400m_firmware_check - check firmware versions are compatible with
 * the driver
 *
 * @i2400m: device descriptor
 *
 * Returns: 0 if ok, < 0 errno code an error and a message in the
 *    kernel log.
 *
 * Long function, but quite simple; first chunk launches the command
 * and double checks the reply for the right TLV. Then we process the
 * TLV (where the meat is).
 *
 * Once we process the TLV that gives us the firmware's interface
 * version, we encode it and save it in i2400m->fw_version for future
 * reference.
 */
int i2400m_firmware_check(struct i2400m *i2400m)
{
        int result;
        struct device *dev = i2400m_dev(i2400m);
        struct sk_buff *ack_skb;
        struct i2400m_l3l4_hdr *cmd;
        const struct i2400m_l3l4_hdr *ack;
        size_t ack_len;
        const struct i2400m_tlv_hdr *tlv;
        const struct i2400m_tlv_l4_message_versions *l4mv;
        char strerr[32];
        unsigned major, minor, branch;

        result = -ENOMEM;
        cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
        if (cmd == NULL)
                goto error_alloc;
        cmd->type = cpu_to_le16(I2400M_MT_GET_LM_VERSION);
        cmd->length = 0;
        cmd->version = cpu_to_le16(I2400M_L3L4_VERSION);

        ack_skb = i2400m_msg_to_dev(i2400m, cmd, sizeof(*cmd));
        if (IS_ERR(ack_skb)) {
                result = PTR_ERR(ack_skb);
                dev_err(dev, "Failed to issue 'get lm version' command: %-d\n",
                        result);
                goto error_msg_to_dev;
        }
        ack = wimax_msg_data_len(ack_skb, &ack_len);
        result = i2400m_msg_check_status(ack, strerr, sizeof(strerr));
        if (result < 0) {
                dev_err(dev, "'get lm version' (0x%04x) command failed: "
                        "%d - %s\n", I2400M_MT_GET_LM_VERSION, result,
                        strerr);
                goto error_cmd_failed;
        }
        tlv = i2400m_tlv_find(i2400m, ack->pl, ack_len - sizeof(*ack),
                              I2400M_TLV_L4_MESSAGE_VERSIONS, sizeof(*l4mv));
        if (tlv == NULL) {
                dev_err(dev, "get lm version: TLV not found (0x%04x)\n",
                        I2400M_TLV_L4_MESSAGE_VERSIONS);
                result = -EIO;
                goto error_no_tlv;
        }
        l4mv = container_of(tlv, typeof(*l4mv), hdr);
        major = le16_to_cpu(l4mv->major);
        minor = le16_to_cpu(l4mv->minor);
        branch = le16_to_cpu(l4mv->branch);
        result = -EINVAL;
        if (major != I2400M_HDIv_MAJOR) {
                dev_err(dev, "unsupported major fw version "
                        "%u.%u.%u\n", major, minor, branch);
                goto error_bad_major;
        }
        result = 0;
        if (minor < I2400M_HDIv_MINOR_2 && minor > I2400M_HDIv_MINOR)
                dev_warn(dev, "untested minor fw version %u.%u.%u\n",
                         major, minor, branch);
        /* Yes, we ignore the branch -- we don't have to track it */
        i2400m->fw_version = major << 16 | minor;
        dev_info(dev, "firmware interface version %u.%u.%u\n",
                 major, minor, branch);
error_bad_major:
error_no_tlv:
error_cmd_failed:
        kfree_skb(ack_skb);
error_msg_to_dev:
        kfree(cmd);
error_alloc:
        return result;
}


/*
 * Send an DoExitIdle command to the device to ask it to go out of
 * basestation-idle mode.
 *
 * @i2400m: device descriptor
 *
 * This starts a renegotiation with the basestation that might involve
 * another crypto handshake with user space.
 *
 * Returns: 0 if ok, < 0 errno code on error.
 */
int i2400m_cmd_exit_idle(struct i2400m *i2400m)
{
        int result;
        struct device *dev = i2400m_dev(i2400m);
        struct sk_buff *ack_skb;
        struct i2400m_l3l4_hdr *cmd;
        char strerr[32];

        result = -ENOMEM;
        cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
        if (cmd == NULL)
                goto error_alloc;
        cmd->type = cpu_to_le16(I2400M_MT_CMD_EXIT_IDLE);
        cmd->length = 0;
        cmd->version = cpu_to_le16(I2400M_L3L4_VERSION);

        ack_skb = i2400m_msg_to_dev(i2400m, cmd, sizeof(*cmd));
        result = PTR_ERR(ack_skb);
        if (IS_ERR(ack_skb)) {
                dev_err(dev, "Failed to issue 'exit idle' command: %d\n",
                        result);
                goto error_msg_to_dev;
        }
        result = i2400m_msg_check_status(wimax_msg_data(ack_skb),
                                         strerr, sizeof(strerr));
        kfree_skb(ack_skb);
error_msg_to_dev:
        kfree(cmd);
error_alloc:
        return result;

}


/*
 * Query the device for its state, update the WiMAX stack's idea of it
 *
 * @i2400m: device descriptor
 *
 * Returns: 0 if ok, < 0 errno code on error.
 *
 * Executes a 'Get State' command and parses the returned
 * TLVs.
 *
 * Because this is almost identical to a 'Report State', we use
 * i2400m_report_state_hook() to parse the answer. This will set the
 * carrier state, as well as the RF Kill switches state.
 */
int i2400m_cmd_get_state(struct i2400m *i2400m)
{
        int result;
        struct device *dev = i2400m_dev(i2400m);
        struct sk_buff *ack_skb;
        struct i2400m_l3l4_hdr *cmd;
        const struct i2400m_l3l4_hdr *ack;
        size_t ack_len;
        char strerr[32];

        result = -ENOMEM;
        cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
        if (cmd == NULL)
                goto error_alloc;
        cmd->type = cpu_to_le16(I2400M_MT_GET_STATE);
        cmd->length = 0;
        cmd->version = cpu_to_le16(I2400M_L3L4_VERSION);

        ack_skb = i2400m_msg_to_dev(i2400m, cmd, sizeof(*cmd));
        if (IS_ERR(ack_skb)) {
                dev_err(dev, "Failed to issue 'get state' command: %ld\n",
                        PTR_ERR(ack_skb));
                result = PTR_ERR(ack_skb);
                goto error_msg_to_dev;
        }
        ack = wimax_msg_data_len(ack_skb, &ack_len);
        result = i2400m_msg_check_status(ack, strerr, sizeof(strerr));
        if (result < 0) {
                dev_err(dev, "'get state' (0x%04x) command failed: "
                        "%d - %s\n", I2400M_MT_GET_STATE, result, strerr);
                goto error_cmd_failed;
        }
        i2400m_report_state_hook(i2400m, ack, ack_len - sizeof(*ack),
                                 "GET STATE");
        result = 0;
        kfree_skb(ack_skb);
error_cmd_failed:
error_msg_to_dev:
        kfree(cmd);
error_alloc:
        return result;
}
EXPORT_SYMBOL_GPL(i2400m_cmd_get_state);


/**
 * Set basic configuration settings
 *
 * @i2400m: device descriptor
 * @args: array of pointers to the TLV headers to send for
 *     configuration (each followed by its payload).
 *     TLV headers and payloads must be properly initialized, with the
 *     right endianess (LE).
 * @arg_size: number of pointers in the @args array
 */
int i2400m_set_init_config(struct i2400m *i2400m,
                           const struct i2400m_tlv_hdr **arg, size_t args)
{
        int result;
        struct device *dev = i2400m_dev(i2400m);
        struct sk_buff *ack_skb;
        struct i2400m_l3l4_hdr *cmd;
        char strerr[32];
        unsigned argc, argsize, tlv_size;
        const struct i2400m_tlv_hdr *tlv_hdr;
        void *buf, *itr;

        d_fnstart(3, dev, "(i2400m %p arg %p args %zu)\n", i2400m, arg, args);
        result = 0;
        if (args == 0)
                goto none;
        /* Compute the size of all the TLVs, so we can alloc a
         * contiguous command block to copy them. */
        argsize = 0;
        for (argc = 0; argc < args; argc++) {
                tlv_hdr = arg[argc];
                argsize += sizeof(*tlv_hdr) + le16_to_cpu(tlv_hdr->length);
        }
        WARN_ON(argc >= 9);     /* As per hw spec */

        /* Alloc the space for the command and TLVs*/
        result = -ENOMEM;
        buf = kzalloc(sizeof(*cmd) + argsize, GFP_KERNEL);
        if (buf == NULL)
                goto error_alloc;
        cmd = buf;
        cmd->type = cpu_to_le16(I2400M_MT_SET_INIT_CONFIG);
        cmd->length = cpu_to_le16(argsize);
        cmd->version = cpu_to_le16(I2400M_L3L4_VERSION);

        /* Copy the TLVs */
        itr = buf + sizeof(*cmd);
        for (argc = 0; argc < args; argc++) {
                tlv_hdr = arg[argc];
                tlv_size = sizeof(*tlv_hdr) + le16_to_cpu(tlv_hdr->length);
                memcpy(itr, tlv_hdr, tlv_size);
                itr += tlv_size;
        }

        /* Send the message! */
        ack_skb = i2400m_msg_to_dev(i2400m, buf, sizeof(*cmd) + argsize);
        result = PTR_ERR(ack_skb);
        if (IS_ERR(ack_skb)) {
                dev_err(dev, "Failed to issue 'init config' command: %d\n",
                        result);

                goto error_msg_to_dev;
        }
        result = i2400m_msg_check_status(wimax_msg_data(ack_skb),
                                         strerr, sizeof(strerr));
        if (result < 0)
                dev_err(dev, "'init config' (0x%04x) command failed: %d - %s\n",
                        I2400M_MT_SET_INIT_CONFIG, result, strerr);
        kfree_skb(ack_skb);
error_msg_to_dev:
        kfree(buf);
error_alloc:
none:
        d_fnend(3, dev, "(i2400m %p arg %p args %zu) = %d\n",
                i2400m, arg, args, result);
        return result;

}
EXPORT_SYMBOL_GPL(i2400m_set_init_config);


/**
 * i2400m_set_idle_timeout - Set the device's idle mode timeout
 *
 * @i2400m: i2400m device descriptor
 *
 * @msecs: milliseconds for the timeout to enter idle mode. Between
 *     100 to 300000 (5m); 0 to disable. In increments of 100.
 *
 * After this @msecs of the link being idle (no data being sent or
 * received), the device will negotiate with the basestation entering
 * idle mode for saving power. The connection is maintained, but
 * getting out of it (done in tx.c) will require some negotiation,
 * possible crypto re-handshake and a possible DHCP re-lease.
 *
 * Only available if fw_version >= 0x00090002.
 *
 * Returns: 0 if ok, < 0 errno code on error.
 */
int i2400m_set_idle_timeout(struct i2400m *i2400m, unsigned msecs)
{
        int result;
        struct device *dev = i2400m_dev(i2400m);
        struct sk_buff *ack_skb;
        struct {
                struct i2400m_l3l4_hdr hdr;
                struct i2400m_tlv_config_idle_timeout cit;
        } *cmd;
        const struct i2400m_l3l4_hdr *ack;
        size_t ack_len;
        char strerr[32];

        result = -ENOSYS;
        if (i2400m_le_v1_3(i2400m))
                goto error_alloc;
        result = -ENOMEM;
        cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
        if (cmd == NULL)
                goto error_alloc;
        cmd->hdr.type = cpu_to_le16(I2400M_MT_GET_STATE);
        cmd->hdr.length = cpu_to_le16(sizeof(*cmd) - sizeof(cmd->hdr));
        cmd->hdr.version = cpu_to_le16(I2400M_L3L4_VERSION);

        cmd->cit.hdr.type =
                cpu_to_le16(I2400M_TLV_CONFIG_IDLE_TIMEOUT);
        cmd->cit.hdr.length = cpu_to_le16(sizeof(cmd->cit.timeout));
        cmd->cit.timeout = cpu_to_le32(msecs);

        ack_skb = i2400m_msg_to_dev(i2400m, cmd, sizeof(*cmd));
        if (IS_ERR(ack_skb)) {
                dev_err(dev, "Failed to issue 'set idle timeout' command: "
                        "%ld\n", PTR_ERR(ack_skb));
                result = PTR_ERR(ack_skb);
                goto error_msg_to_dev;
        }
        ack = wimax_msg_data_len(ack_skb, &ack_len);
        result = i2400m_msg_check_status(ack, strerr, sizeof(strerr));
        if (result < 0) {
                dev_err(dev, "'set idle timeout' (0x%04x) command failed: "
                        "%d - %s\n", I2400M_MT_GET_STATE, result, strerr);
                goto error_cmd_failed;
        }
        result = 0;
        kfree_skb(ack_skb);
error_cmd_failed:
error_msg_to_dev:
        kfree(cmd);
error_alloc:
        return result;
}


/**
 * i2400m_dev_initialize - Initialize the device once communications are ready
 *
 * @i2400m: device descriptor
 *
 * Returns: 0 if ok, < 0 errno code on error.
 *
 * Configures the device to work the way we like it.
 *
 * At the point of this call, the device is registered with the WiMAX
 * and netdev stacks, firmware is uploaded and we can talk to the
 * device normally.
 */
int i2400m_dev_initialize(struct i2400m *i2400m)
{
        int result;
        struct device *dev = i2400m_dev(i2400m);
        struct i2400m_tlv_config_idle_parameters idle_params;
        struct i2400m_tlv_config_idle_timeout idle_timeout;
        struct i2400m_tlv_config_d2h_data_format df;
        struct i2400m_tlv_config_dl_host_reorder dlhr;
        const struct i2400m_tlv_hdr *args[9];
        unsigned argc = 0;

        d_fnstart(3, dev, "(i2400m %p)\n", i2400m);
        /* Disable idle mode? (enabled by default) */
        if (i2400m_idle_mode_disabled) {
                if (i2400m_le_v1_3(i2400m)) {
                        idle_params.hdr.type =
                                cpu_to_le16(I2400M_TLV_CONFIG_IDLE_PARAMETERS);
                        idle_params.hdr.length = cpu_to_le16(
                                sizeof(idle_params) - sizeof(idle_params.hdr));
                        idle_params.idle_timeout = 0;
                        idle_params.idle_paging_interval = 0;
                        args[argc++] = &idle_params.hdr;
                } else {
                        idle_timeout.hdr.type =
                                cpu_to_le16(I2400M_TLV_CONFIG_IDLE_TIMEOUT);
                        idle_timeout.hdr.length = cpu_to_le16(
                                sizeof(idle_timeout) - sizeof(idle_timeout.hdr));
                        idle_timeout.timeout = 0;
                        args[argc++] = &idle_timeout.hdr;
                }
        }
        if (i2400m_ge_v1_4(i2400m)) {
                /* Enable extended RX data format? */
                df.hdr.type =
                        cpu_to_le16(I2400M_TLV_CONFIG_D2H_DATA_FORMAT);
                df.hdr.length = cpu_to_le16(
                        sizeof(df) - sizeof(df.hdr));
                df.format = 1;
                args[argc++] = &df.hdr;

                /* Enable RX data reordering?
                 * (switch flipped in rx.c:i2400m_rx_setup() after fw upload) */
                if (i2400m->rx_reorder) {
                        dlhr.hdr.type =
                                cpu_to_le16(I2400M_TLV_CONFIG_DL_HOST_REORDER);
                        dlhr.hdr.length = cpu_to_le16(
                                sizeof(dlhr) - sizeof(dlhr.hdr));
                        dlhr.reorder = 1;
                        args[argc++] = &dlhr.hdr;
                }
        }
        result = i2400m_set_init_config(i2400m, args, argc);
        if (result < 0)
                goto error;
        /*
         * Update state: Here it just calls a get state; parsing the
         * result (System State TLV and RF Status TLV [done in the rx
         * path hooks]) will set the hardware and software RF-Kill
         * status.
         */
        result = i2400m_cmd_get_state(i2400m);
error:
        if (result < 0)
                dev_err(dev, "failed to initialize the device: %d\n", result);
        d_fnend(3, dev, "(i2400m %p) = %d\n", i2400m, result);
        return result;
}


/**
 * i2400m_dev_shutdown - Shutdown a running device
 *
 * @i2400m: device descriptor
 *
 * Gracefully stops the device, moving it to the lowest power
 * consumption state possible.
 */
void i2400m_dev_shutdown(struct i2400m *i2400m)
{
        int result = -ENODEV;
        struct device *dev = i2400m_dev(i2400m);

        d_fnstart(3, dev, "(i2400m %p)\n", i2400m);
        result = i2400m->bus_reset(i2400m, I2400M_RT_WARM);
        d_fnend(3, dev, "(i2400m %p) = void [%d]\n", i2400m, result);
        return;
}