ocs_pm.c

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/*
 * Copyright (c) 2011-2015, Emulex
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 *    this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
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 *    may be used to endorse or promote products derived from this software
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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/**
 * @file
 * API for OCS power managment
 *
 */

#include "ocs.h"
#include "ocs_pm.h"

/**
 * @brief Handle Power Management Request
 *
 * Function is called by management or OS to request a change in the power state of
 * the device controlled by the OCS driver.   The API supports requesting the following:
 *
 * OCS_PM_PREPARE   The device (in state S0) is notified that a power state change is
 *          forthcoming.
 * OCS_PM_SLEEP     The device is transitioned to state S3 (sleep/standby).
 * OCS_PM_HIBERNATE The device is transitioned to state S4 (hibernate)
 * OCS_PM_RESUME    The device resumes
 * OCS_PM_CANCEL    Cancel any pending request.  If a callback was expected for the
 *          pending request, the callback will be made with an error status
 *          indicating the request was cancelled.
 *
 * @param ocs pointer to device structure
 * @param msg power manatement request message
 * @param callback callback function to be invoked when request has completed.
 * @param arg arbitrary argument that is passed to the callback
 *
 * Arguments to the callback function are as follows:
 *
 *  ocs pointer to device structure
 *  status  integer value indicating the success or failure of the requested operation. 0 for
 *      success, negative value for failure.
 *  arg pointer to the caller supplied argument
 *
 * @return 0 for success, callback is expected
 *  1 for success, no callback
 *  negative value for failure, no callback
 *
 * For the OCS driver on the SLI4 adapters at the time of writing, SLEEP and HIBERNATE both transition to S3,
 * assumming power on the device and memory is retained.   IO's are quiesced, the port is offlined,
 * interrupts are disabled, link is taken down.  Back end calls will result, not disimilar to the
 * bahavior of loss of link.
 *
 * RESUME will bring the port back online, initiate discovery (for initiator).
 */
int32_t
ocs_pm_request(ocs_t *ocs, ocs_pm_msg_e msg, int32_t (*callback)(ocs_t *ocs, int32_t status, void *arg), void *arg)
{
    int32_t rc = 1;

    switch (msg) {
    case OCS_PM_PREPARE:
        rc = 1;
        break;
    case OCS_PM_SLEEP:
        rc = ocs_device_detach(ocs);
        if (rc == 0) {
            ocs->pm_context.pm_state = OCS_PM_STATE_S3;
            rc = 1;
        }
        break;
    case OCS_PM_HIBERNATE:
        rc = ocs_device_detach(ocs);
        if (rc == 0) {
            ocs->pm_context.pm_state = OCS_PM_STATE_S4;
            rc = 1;
        }
        break;
    case OCS_PM_RESUME: {
        rc = ocs_device_attach(ocs);
        if (rc == 0) {
            ocs->pm_context.pm_state = OCS_PM_STATE_S0;
            rc = 1;
        }
        break;
    }
    }
    return rc;
}


/**
 * @brief Return driver power state
 *
 * The current power state is returned.  Note, that in some implementations, the power state may differ
 * from that requested and completed using ocs_pm_request(). (SLI4 HIBERNATE requests will sleep)
 *
 * @param ocs pointer to device structure
 *
 * @return the current power state is returned
 */
ocs_pm_state_e
ocs_pm_get_state(ocs_t *ocs)
{
    return ocs->pm_context.pm_state;
}

/**
 * @brief Return driver power state as an ascii string
 *
 * The current power state is returned as a string.
 *
 * @param ocs poitner to device structure
 *
 * @return returns power state string
 */
const char *ocs_pm_get_state_string(ocs_t *ocs)
{
    switch (ocs_pm_get_state(ocs)) {
    case OCS_PM_STATE_S0:   return "S0";
    case OCS_PM_STATE_S1:   return "S1";
    case OCS_PM_STATE_S2:   return "S2";
    case OCS_PM_STATE_S3:   return "S3";
    case OCS_PM_STATE_S4:   return "S4";
    }
    return "S?";
}