openwrt-xburst/target/linux/s3c24xx/files-2.6.30/drivers/ar6000/bmi/bmi.c

/*
 * Copyright (c) 2004-2007 Atheros Communications Inc.
 * All rights reserved.
 *
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2 as
 *  published by the Free Software Foundation;
 *
 *  Software distributed under the License is distributed on an "AS
 *  IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 *  implied. See the License for the specific language governing
 *  rights and limitations under the License.
 *
 *
 *
 */

#include "hif.h"
#include "bmi.h"
#include "htc_api.h"
#include "bmi_internal.h"

/*
Although we had envisioned BMI to run on top of HTC, this is not what the
final implementation boiled down to on dragon. Its a part of BSP and does
not use the HTC protocol either. On the host side, however, we were still
living with the original idea. I think the time has come to accept the truth
and separate it from HTC which has been carrying BMI's burden all this while.
It shall make HTC state machine relatively simpler
*/

/* APIs visible to the driver */
void
BMIInit(void)
{
    bmiDone = FALSE;
}

A_STATUS
BMIDone(HIF_DEVICE *device)
{
    A_STATUS status;
    A_UINT32 cid;

    if (bmiDone) {
        AR_DEBUG_PRINTF (ATH_DEBUG_BMI, ("BMIDone skipped\n"));
        return A_OK;
    }

    AR_DEBUG_PRINTF(ATH_DEBUG_BMI, ("BMI Done: Enter (device: 0x%p)\n", device));
    bmiDone = TRUE;
    cid = BMI_DONE;

    status = bmiBufferSend(device, (A_UCHAR *)&cid, sizeof(cid));
    if (status != A_OK) {
        AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("Unable to write to the device\n"));
        return A_ERROR;
    }
    AR_DEBUG_PRINTF(ATH_DEBUG_BMI, ("BMI Done: Exit\n"));

    return A_OK;
}

A_STATUS
BMIGetTargetInfo(HIF_DEVICE *device, struct bmi_target_info *targ_info)
{
    A_STATUS status;
    A_UINT32 cid;

    if (bmiDone) {
        AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("Command disallowed\n"));
        return A_ERROR;
    }

    AR_DEBUG_PRINTF(ATH_DEBUG_BMI, ("BMI Get Target Info: Enter (device: 0x%p)\n", device));
    cid = BMI_GET_TARGET_INFO;

    status = bmiBufferSend(device, (A_UCHAR *)&cid, sizeof(cid));
    if (status != A_OK) {
        AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("Unable to write to the device\n"));
        return A_ERROR;
    }

    status = bmiBufferReceive(device, (A_UCHAR *)&targ_info->target_ver,
                                                sizeof(targ_info->target_ver));
    if (status != A_OK) {
        AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("Unable to read Target Version from the device\n"));
        return A_ERROR;
    }

    if (targ_info->target_ver == TARGET_VERSION_SENTINAL) {
        /* Determine how many bytes are in the Target's targ_info */
        status = bmiBufferReceive(device, (A_UCHAR *)&targ_info->target_info_byte_count,
                                            sizeof(targ_info->target_info_byte_count));
        if (status != A_OK) {
            AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("Unable to read Target Info Byte Count from the device\n"));
            return A_ERROR;
        }

        /*
         * The Target's targ_info doesn't match the Host's targ_info.
         * We need to do some backwards compatibility work to make this OK.
         */
        A_ASSERT(targ_info->target_info_byte_count == sizeof(*targ_info));

        /* Read the remainder of the targ_info */
        status = bmiBufferReceive(device,
                        ((A_UCHAR *)targ_info)+sizeof(targ_info->target_info_byte_count),
                        sizeof(*targ_info)-sizeof(targ_info->target_info_byte_count));
        if (status != A_OK) {
            AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("Unable to read Target Info (%d bytes) from the device\n",
                        					targ_info->target_info_byte_count));
            return A_ERROR;
        }
    } else {
        /*
         * Target must be an AR6001 whose firmware does not
         * support BMI_GET_TARGET_INFO.  Construct the data
         * that it would have sent.
         */
        targ_info->target_info_byte_count = sizeof(targ_info);
        targ_info->target_type = TARGET_TYPE_AR6001;
    }

    AR_DEBUG_PRINTF(ATH_DEBUG_BMI, ("BMI Get Target Info: Exit (ver: 0x%x type: 0x%x)\n",
        							targ_info->target_ver, targ_info->target_type));
    printk("BMI Get Target Info: Exit (ver: 0x%x type: 0x%x)\n",
	   targ_info->target_ver, targ_info->target_type);

    return A_OK;
}

A_STATUS
BMIReadMemory(HIF_DEVICE *device,
              A_UINT32 address,
              A_UCHAR *buffer,
              A_UINT32 length)
{
    A_UINT32 cid;
    A_STATUS status;
    A_UINT32 offset;
    A_UINT32 remaining, rxlen;
    static A_UCHAR data[BMI_DATASZ_MAX + sizeof(cid) + sizeof(address) + sizeof(length)];
    memset (&data, 0, BMI_DATASZ_MAX + sizeof(cid) + sizeof(address) + sizeof(length));

    if (bmiDone) {
        AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("Command disallowed\n"));
        return A_ERROR;
    }

    AR_DEBUG_PRINTF(ATH_DEBUG_BMI,
       			("BMI Read Memory: Enter (device: 0x%p, address: 0x%x, length: %d)\n",
        			device, address, length));

    cid = BMI_READ_MEMORY;

    remaining = length;

    while (remaining)
    {
        rxlen = (remaining < BMI_DATASZ_MAX) ? remaining : BMI_DATASZ_MAX;
        offset = 0;
        A_MEMCPY(&data[offset], &cid, sizeof(cid));
        offset += sizeof(cid);
        A_MEMCPY(&data[offset], &address, sizeof(address));
        offset += sizeof(address);
        A_MEMCPY(&data[offset], &rxlen, sizeof(rxlen));
        offset += sizeof(length);

        status = bmiBufferSend(device, data, offset);
        if (status != A_OK) {
            AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("Unable to write to the device\n"));
            return A_ERROR;
        }
        status = bmiBufferReceive(device, data, rxlen);
        if (status != A_OK) {
            AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("Unable to read from the device\n"));
            return A_ERROR;
        }
        A_MEMCPY(&buffer[length - remaining], data, rxlen);
        remaining -= rxlen; address += rxlen;
    }

    AR_DEBUG_PRINTF(ATH_DEBUG_BMI, ("BMI Read Memory: Exit\n"));
    return A_OK;
}

A_STATUS
BMIWriteMemory(HIF_DEVICE *device,
               A_UINT32 address,
               A_UCHAR *buffer,
               A_UINT32 length)
{
    A_UINT32 cid;
    A_STATUS status;
    A_UINT32 offset;
    A_UINT32 remaining, txlen;
    const A_UINT32 header = sizeof(cid) + sizeof(address) + sizeof(length);
    static A_UCHAR data[BMI_DATASZ_MAX + sizeof(cid) + sizeof(address) + sizeof(length)];
	memset (&data, 0, header);

    if (bmiDone) {
        AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("Command disallowed\n"));
        return A_ERROR;
    }

    AR_DEBUG_PRINTF(ATH_DEBUG_BMI,
         ("BMI Write Memory: Enter (device: 0x%p, address: 0x%x, length: %d)\n",
         device, address, length));

    cid = BMI_WRITE_MEMORY;

    remaining = length;
    while (remaining)
    {
        txlen = (remaining < (BMI_DATASZ_MAX - header)) ?
                                       remaining : (BMI_DATASZ_MAX - header);
        offset = 0;
        A_MEMCPY(&data[offset], &cid, sizeof(cid));
        offset += sizeof(cid);
        A_MEMCPY(&data[offset], &address, sizeof(address));
        offset += sizeof(address);
        A_MEMCPY(&data[offset], &txlen, sizeof(txlen));
        offset += sizeof(txlen);
        A_MEMCPY(&data[offset], &buffer[length - remaining], txlen);
        offset += txlen;
        status = bmiBufferSend(device, data, offset);
        if (status != A_OK) {
            AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("Unable to write to the device\n"));
            return A_ERROR;
        }
        remaining -= txlen; address += txlen;
    }

    AR_DEBUG_PRINTF(ATH_DEBUG_BMI, ("BMI Write Memory: Exit\n"));

    return A_OK;
}

A_STATUS
BMIExecute(HIF_DEVICE *device,
           A_UINT32 address,
           A_UINT32 *param)
{
    A_UINT32 cid;
    A_STATUS status;
    A_UINT32 offset;
    static A_UCHAR data[sizeof(cid) + sizeof(address) + sizeof(*param)];
    memset (&data, 0, sizeof(cid) + sizeof(address) + sizeof(*param));

    if (bmiDone) {
        AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("Command disallowed\n"));
        return A_ERROR;
    }

    AR_DEBUG_PRINTF(ATH_DEBUG_BMI,
       ("BMI Execute: Enter (device: 0x%p, address: 0x%x, param: %d)\n",
        device, address, *param));

    cid = BMI_EXECUTE;

    offset = 0;
    A_MEMCPY(&data[offset], &cid, sizeof(cid));
    offset += sizeof(cid);
    A_MEMCPY(&data[offset], &address, sizeof(address));
    offset += sizeof(address);
    A_MEMCPY(&data[offset], param, sizeof(*param));
    offset += sizeof(*param);
    status = bmiBufferSend(device, data, offset);
    if (status != A_OK) {
        AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("Unable to write to the device\n"));
        return A_ERROR;
    }

    status = bmiBufferReceive(device, data, sizeof(*param));
    if (status != A_OK) {
        AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("Unable to read from the device\n"));
        return A_ERROR;
    }

    A_MEMCPY(param, data, sizeof(*param));

    AR_DEBUG_PRINTF(ATH_DEBUG_BMI, ("BMI Execute: Exit (param: %d)\n", *param));
    return A_OK;
}

A_STATUS
BMISetAppStart(HIF_DEVICE *device,
               A_UINT32 address)
{
    A_UINT32 cid;
    A_STATUS status;
    A_UINT32 offset;
    static A_UCHAR data[sizeof(cid) + sizeof(address)];
    memset (&data, 0, sizeof(cid) + sizeof(address));

    if (bmiDone) {
        AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("Command disallowed\n"));
        return A_ERROR;
    }

    AR_DEBUG_PRINTF(ATH_DEBUG_BMI,
       ("BMI Set App Start: Enter (device: 0x%p, address: 0x%x)\n",
        device, address));

    cid = BMI_SET_APP_START;

    offset = 0;
    A_MEMCPY(&data[offset], &cid, sizeof(cid));
    offset += sizeof(cid);
    A_MEMCPY(&data[offset], &address, sizeof(address));
    offset += sizeof(address);
    status = bmiBufferSend(device, data, offset);
    if (status != A_OK) {
        AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("Unable to write to the device\n"));
        return A_ERROR;
    }

    AR_DEBUG_PRINTF(ATH_DEBUG_BMI, ("BMI Set App Start: Exit\n"));
    return A_OK;
}

A_STATUS
BMIReadSOCRegister(HIF_DEVICE *device,
                   A_UINT32 address,
                   A_UINT32 *param)
{
    A_UINT32 cid;
    A_STATUS status;
    A_UINT32 offset;
    static A_UCHAR data[sizeof(cid) + sizeof(address)];
    memset (&data, 0, sizeof(cid) + sizeof(address));

    if (bmiDone) {
        AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("Command disallowed\n"));
        return A_ERROR;
    }

    AR_DEBUG_PRINTF(ATH_DEBUG_BMI,
       ("BMI Read SOC Register: Enter (device: 0x%p, address: 0x%x)\n",
       device, address));

    cid = BMI_READ_SOC_REGISTER;

    offset = 0;
    A_MEMCPY(&data[offset], &cid, sizeof(cid));
    offset += sizeof(cid);
    A_MEMCPY(&data[offset], &address, sizeof(address));
    offset += sizeof(address);

    status = bmiBufferSend(device, data, offset);
    if (status != A_OK) {
        AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("Unable to write to the device\n"));
        return A_ERROR;
    }

    status = bmiBufferReceive(device, data, sizeof(*param));
    if (status != A_OK) {
        AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("Unable to read from the device\n"));
        return A_ERROR;
    }
    A_MEMCPY(param, data, sizeof(*param));

    AR_DEBUG_PRINTF(ATH_DEBUG_BMI, ("BMI Read SOC Register: Exit (value: %d)\n", *param));
    return A_OK;
}

A_STATUS
BMIWriteSOCRegister(HIF_DEVICE *device,
                    A_UINT32 address,
                    A_UINT32 param)
{
    A_UINT32 cid;
    A_STATUS status;
    A_UINT32 offset;
    static A_UCHAR data[sizeof(cid) + sizeof(address) + sizeof(param)];

    memset (&data, 0, sizeof(cid) + sizeof(address) + sizeof(param));

    if (bmiDone) {
        AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("Command disallowed\n"));
        return A_ERROR;
    }

    AR_DEBUG_PRINTF(ATH_DEBUG_BMI,
     ("BMI Write SOC Register: Enter (device: 0x%p, address: 0x%x, param: %d)\n",
     device, address, param));

    cid = BMI_WRITE_SOC_REGISTER;

    offset = 0;
    A_MEMCPY(&data[offset], &cid, sizeof(cid));
    offset += sizeof(cid);
    A_MEMCPY(&data[offset], &address, sizeof(address));
    offset += sizeof(address);
    A_MEMCPY(&data[offset], &param, sizeof(param));
    offset += sizeof(param);
    status = bmiBufferSend(device, data, offset);
    if (status != A_OK) {
        AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("Unable to write to the device\n"));
        return A_ERROR;
    }

    AR_DEBUG_PRINTF(ATH_DEBUG_BMI, ("BMI Read SOC Register: Exit\n"));
    return A_OK;
}

A_STATUS
BMIrompatchInstall(HIF_DEVICE *device,
                   A_UINT32 ROM_addr,
                   A_UINT32 RAM_addr,
                   A_UINT32 nbytes,
                   A_UINT32 do_activate,
                   A_UINT32 *rompatch_id)
{
    A_UINT32 cid;
    A_STATUS status;
    A_UINT32 offset;
    static A_UCHAR data[sizeof(cid) + sizeof(ROM_addr) + sizeof(RAM_addr) +
                                sizeof(nbytes) + sizeof(do_activate)];

	memset (&data, 0, sizeof(cid) + sizeof(ROM_addr) + sizeof(RAM_addr) +
                      sizeof(nbytes) + sizeof(do_activate));

    if (bmiDone) {
        AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("Command disallowed\n"));
        return A_ERROR;
    }

    AR_DEBUG_PRINTF(ATH_DEBUG_BMI,
         ("BMI rompatch Install: Enter (device: 0x%p, ROMaddr: 0x%x, RAMaddr: 0x%x length: %d activate: %d)\n",
         device, ROM_addr, RAM_addr, nbytes, do_activate));

    cid = BMI_ROMPATCH_INSTALL;

    offset = 0;
    A_MEMCPY(&data[offset], &cid, sizeof(cid));
    offset += sizeof(cid);
    A_MEMCPY(&data[offset], &ROM_addr, sizeof(ROM_addr));
    offset += sizeof(ROM_addr);
    A_MEMCPY(&data[offset], &RAM_addr, sizeof(RAM_addr));
    offset += sizeof(RAM_addr);
    A_MEMCPY(&data[offset], &nbytes, sizeof(nbytes));
    offset += sizeof(nbytes);
    A_MEMCPY(&data[offset], &do_activate, sizeof(do_activate));
    offset += sizeof(do_activate);
    status = bmiBufferSend(device, data, offset);
    if (status != A_OK) {
        AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("Unable to write to the device\n"));
        return A_ERROR;
    }

    status = bmiBufferReceive(device, (A_UCHAR *)rompatch_id, sizeof(*rompatch_id));
    if (status != A_OK) {
        AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("Unable to read from the device\n"));
        return A_ERROR;
    }

    AR_DEBUG_PRINTF(ATH_DEBUG_BMI, ("BMI rompatch Install: (rompatch_id=%d)\n", *rompatch_id));
    return A_OK;
}

A_STATUS
BMIrompatchUninstall(HIF_DEVICE *device,
                     A_UINT32 rompatch_id)
{
    A_UINT32 cid;
    A_STATUS status;
    A_UINT32 offset;
    static A_UCHAR data[sizeof(cid) + sizeof(rompatch_id)];
    memset (&data, 0, sizeof(cid) + sizeof(rompatch_id));

    if (bmiDone) {
        AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("Command disallowed\n"));
        return A_ERROR;
    }

    AR_DEBUG_PRINTF(ATH_DEBUG_BMI,
         ("BMI rompatch Uninstall: Enter (device: 0x%p, rompatch_id: %d)\n",
         								 device, rompatch_id));

    cid = BMI_ROMPATCH_UNINSTALL;

    offset = 0;
    A_MEMCPY(&data[offset], &cid, sizeof(cid));
    offset += sizeof(cid);
    A_MEMCPY(&data[offset], &rompatch_id, sizeof(rompatch_id));
    offset += sizeof(rompatch_id);
    status = bmiBufferSend(device, data, offset);
    if (status != A_OK) {
        AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("Unable to write to the device\n"));
        return A_ERROR;
    }

    AR_DEBUG_PRINTF(ATH_DEBUG_BMI, ("BMI rompatch UNinstall: (rompatch_id=0x%x)\n", rompatch_id));
    return A_OK;
}

static A_STATUS
_BMIrompatchChangeActivation(HIF_DEVICE *device,
                             A_UINT32 rompatch_count,
                             A_UINT32 *rompatch_list,
                             A_UINT32 do_activate)
{
    A_UINT32 cid;
    A_STATUS status;
    A_UINT32 offset;
    static A_UCHAR data[BMI_DATASZ_MAX + sizeof(cid) + sizeof(rompatch_count)];
    A_UINT32 length;

	memset (&data, 0, BMI_DATASZ_MAX + sizeof(cid) + sizeof(rompatch_count));

    if (bmiDone) {
        AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("Command disallowed\n"));
        return A_ERROR;
    }

    AR_DEBUG_PRINTF(ATH_DEBUG_BMI,
         ("BMI Change rompatch Activation: Enter (device: 0x%p, count: %d)\n",
           device, rompatch_count));

    cid = do_activate ? BMI_ROMPATCH_ACTIVATE : BMI_ROMPATCH_DEACTIVATE;

    offset = 0;
    A_MEMCPY(&data[offset], &cid, sizeof(cid));
    offset += sizeof(cid);
    A_MEMCPY(&data[offset], &rompatch_count, sizeof(rompatch_count));
    offset += sizeof(rompatch_count);
    length = rompatch_count * sizeof(*rompatch_list);
    A_MEMCPY(&data[offset], rompatch_list, length);
    offset += length;
    status = bmiBufferSend(device, data, offset);
    if (status != A_OK) {
        AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("Unable to write to the device\n"));
        return A_ERROR;
    }

    AR_DEBUG_PRINTF(ATH_DEBUG_BMI, ("BMI Change rompatch Activation: Exit\n"));

    return A_OK;
}

A_STATUS
BMIrompatchActivate(HIF_DEVICE *device,
                    A_UINT32 rompatch_count,
                    A_UINT32 *rompatch_list)
{
    return _BMIrompatchChangeActivation(device, rompatch_count, rompatch_list, 1);
}

A_STATUS
BMIrompatchDeactivate(HIF_DEVICE *device,
                      A_UINT32 rompatch_count,
                      A_UINT32 *rompatch_list)
{
    return _BMIrompatchChangeActivation(device, rompatch_count, rompatch_list, 0);
}

/* BMI Access routines */
A_STATUS
bmiBufferSend(HIF_DEVICE *device,
              A_UCHAR *buffer,
              A_UINT32 length)
{
    A_STATUS status;
    A_UINT32 timeout;
    A_UINT32 address;
    static A_UINT32 cmdCredits;
    A_UINT32 mboxAddress[HTC_MAILBOX_NUM_MAX];

    HIFConfigureDevice(device, HIF_DEVICE_GET_MBOX_ADDR,
                       &mboxAddress, sizeof(mboxAddress));

    cmdCredits = 0;
    timeout = BMI_COMMUNICATION_TIMEOUT;

    while(timeout-- && !cmdCredits) {
        /* Read the counter register to get the command credits */
        address = COUNT_DEC_ADDRESS + (HTC_MAILBOX_NUM_MAX + ENDPOINT1) * 4;
        /* hit the credit counter with a 4-byte access, the first byte read will hit the counter and cause
         * a decrement, while the remaining 3 bytes has no effect.  The rationale behind this is to
         * make all HIF accesses 4-byte aligned */
        status = HIFReadWrite(device, address, (A_UINT8 *)&cmdCredits, 4,
            HIF_RD_SYNC_BYTE_INC, NULL);
        if (status != A_OK) {
            AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("Unable to decrement the command credit count register\n"));
            return A_ERROR;
        }
        /* the counter is only 8=bits, ignore anything in the upper 3 bytes */
        cmdCredits &= 0xFF;
    }

    if (cmdCredits) {
        address = mboxAddress[ENDPOINT1];
        status = HIFReadWrite(device, address, buffer, length,
            HIF_WR_SYNC_BYTE_INC, NULL);
        if (status != A_OK) {
            AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("Unable to send the BMI data to the device\n"));
            return A_ERROR;
        }
    } else {
        AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("BMI Communication timeout\n"));
        return A_ERROR;
    }

    return status;
}

A_STATUS
bmiBufferReceive(HIF_DEVICE *device,
                 A_UCHAR *buffer,
                 A_UINT32 length)
{
    A_STATUS status;
    A_UINT32 address;
    A_UINT32 timeout;
    static A_UINT32 cmdCredits;
    A_UINT32 mboxAddress[HTC_MAILBOX_NUM_MAX];

    HIFConfigureDevice(device, HIF_DEVICE_GET_MBOX_ADDR,
                       &mboxAddress, sizeof(mboxAddress));

    cmdCredits = 0;
    timeout = BMI_COMMUNICATION_TIMEOUT;
    while(timeout-- && !cmdCredits) {
        /* Read the counter register to get the command credits */
        address = COUNT_ADDRESS + (HTC_MAILBOX_NUM_MAX + ENDPOINT1) * 1;
        /* read the counter using a 4-byte read.  Since the counter is NOT auto-decrementing,
         * we can read this counter multiple times using a non-incrementing address mode.
         * The rationale here is to make all HIF accesses a multiple of 4 bytes */
        status = HIFReadWrite(device, address, (A_UINT8 *)&cmdCredits, sizeof(cmdCredits),
            HIF_RD_SYNC_BYTE_FIX, NULL);
        if (status != A_OK) {
            AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("Unable to read the command credit count register\n"));
            return A_ERROR;
        }
            /* we did a 4-byte read to the same count register so mask off upper bytes */
        cmdCredits &= 0xFF;
        status = A_ERROR;
    }

    if (cmdCredits) {
        address = mboxAddress[ENDPOINT1];
        status = HIFReadWrite(device, address, buffer, length,
            HIF_RD_SYNC_BYTE_INC, NULL);
        if (status != A_OK) {
            AR_DEBUG_PRINTF(ATH_DEBUG_ERR, ("Unable to read the BMI data from the device\n"));
            return A_ERROR;
        }
    } else {
        AR_DEBUG_PRINTF(ATH_DEBUG_BMI, ("BMI Communication timeout\n"));
        return A_ERROR;
    }

    return status;
}