/*
 *
 * pal_osProtect.h
 * Description:
 * see below
 *
 *

  This file is provided under a dual BSD/GPLv2 license.  When using or
  redistributing this file, you may do so under either license.

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  published by the Free Software Foundation.

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  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  The full GNU General Public License is included in this distribution
  in the file called LICENSE.GPL.


  Contact Information:
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  BSD LICENSE

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    * Redistributions in binary form must reproduce the above copyright
      notice, this list of conditions and the following disclaimer in
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    * 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
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*/


/** \file   pal_osProtect.h
    \brief  OsPROTECT Services Header File
    ===================================================================
    The OsPROTECT models various levels of reentrancy protection
    for use while writing critical sections in user code. critical
    sections are those parts of user code that needs to run atomically
    in some sense. Meaning, single threading is called for. However,
    the degree of protection sought by user varies based on nature
    of code he is writing.

    It is possible that for some regions of code, user needs ultimate
    degree of protection where all external interrupts are blocked,
    essentially locking out the CPU exclusively for the critical
    section of code. On the other hand user may wish to merely avoid
    thread or task switch from occuring inside said region of code,
    but he may wish to entertain ISRs to run if so required.

    Depending on the underlying OS, the number of levels of protection
    offered may vary. At the least, two basic levels of protection are
    supported --

    - PAL_OSPROTECT_INTERRUPTS - Mask interrupts globally. This has
      real-time implications and must be used with descretion.
      If blocking/unblocking of specific interrupt lines is desired,
      one is reffered to APIs listed in pal_sys.h file.

    - PAL_OSPROTECT_SCHEDULER - Only turns off Kernel scheduler
      completely, but still allows h/w interrupts from being serviced.

    Protection levels 0 to N (max positive Int) are platform specific
    ===================================================================


    \author     PSP Architecture Team
    \version    1.0
 */

#ifndef __PAL_OSPROTECT_H__
#define __PAL_OSPROTECT_H__

#include "pal_defs.h"
#include "pal_os.h"

/**
 * \defgroup PalOSProtect PAL OS Protect Interface
 *
 * PAL OS Protect Interface
 * \{
 */

/** \name PAL OS Protect Interface
 *  PAL OS Protect Interface
 * \{
 */

#define PAL_OSPROTECT_INTERRUPT (0x01)
#define PAL_OSPROTECT_SCHEDULER (0x02)

/**
 * \brief   PAL OS Protect Entry
 *
 *      This function saves the current state of protection in cookie
 *      variable passed by caller. It then applies the requested level
 *      of protection
 * \param   level is bitmask identifier of the desired type of
 *  		protection.
 * \param   cookie is memory location where current state of protection is
 *      saved for future use while restoring it via PAL_osProtectExit()
 * \note    user is not expected to interpret the cookie in any manner. It
 *      is intended for use in terminating the presently enforced
 *      protection via a matching PAL_osProtectExit() call discssed
 *      later in this file.
 * \return  None
 */
PAL_INLINE void PAL_osProtectEntry(Uint32 level, Uint32* cookie);

/**
 * \brief   PAL OS Protect Exit
 *
 *      This function undoes the protection enforced to original state
 *      as is specified by the cookie passed.
 * \param   level is numeric identifier of the desired degree of protection.
 * \param   cookie is original state of protection at time when the
 *      corresponding PAL_osProtectEnter() was called.
 * \return  None
 */
PAL_INLINE void PAL_osProtectExit(Uint32 level, Uint32 cookie);

/*\}*/
/*\}*/

#endif /* _PAL_OSPROTECT_H_ */