FreeBSD/Linux Kernel Cross Reference
sys/dev/acpica/Osd/OsdSynch.c

     /*-
      * Copyright (c) 2000 Michael Smith
      * Copyright (c) 2000 BSDi
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
      * 1. Redistributions of source code must retain the above copyright
     *    notice, 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 and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
     *
     *      $FreeBSD$
     */
    
    /*
     * 6.1 : Mutual Exclusion and Synchronisation
     */
    
    #include "acpi.h"
    
    #include "opt_acpi.h"
    #include <sys/kernel.h>
    #include <sys/malloc.h>
    #include <sys/sysctl.h>
    #include <sys/lock.h>
    #include <sys/mutex.h>
    
    #define _COMPONENT      ACPI_OS_SERVICES
    ACPI_MODULE_NAME("SYNCH")
    
    MALLOC_DEFINE(M_ACPISEM, "acpisem", "ACPI semaphore");
    
    #define AS_LOCK(as)     mtx_lock(&(as)->as_mtx)
    #define AS_UNLOCK(as)   mtx_unlock(&(as)->as_mtx)
    
    /*
     * Simple counting semaphore implemented using a mutex.  (Subsequently used
     * in the OSI code to implement a mutex.  Go figure.)
     */
    struct acpi_semaphore {
        struct mtx  as_mtx;
        UINT32      as_units;
        UINT32      as_maxunits;
        UINT32      as_pendings;
        UINT32      as_resetting;
        UINT32      as_timeouts;
    };
    
    #ifndef ACPI_NO_SEMAPHORES
    #ifndef ACPI_SEMAPHORES_MAX_PENDING
    #define ACPI_SEMAPHORES_MAX_PENDING     4
    #endif
    static int      acpi_semaphore_debug = 0;
    TUNABLE_INT("debug.acpi_semaphore_debug", &acpi_semaphore_debug);
    SYSCTL_DECL(_debug_acpi);
    SYSCTL_INT(_debug_acpi, OID_AUTO, semaphore_debug, CTLFLAG_RW,
               &acpi_semaphore_debug, 0, "Enable ACPI semaphore debug messages");
    #endif /* !ACPI_NO_SEMAPHORES */
    
    ACPI_STATUS
    AcpiOsCreateSemaphore(UINT32 MaxUnits, UINT32 InitialUnits,
        ACPI_HANDLE *OutHandle)
    {
    #ifndef ACPI_NO_SEMAPHORES
        struct acpi_semaphore       *as;
    
        ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
    
        if (OutHandle == NULL)
            return_ACPI_STATUS (AE_BAD_PARAMETER);
        if (InitialUnits > MaxUnits)
            return_ACPI_STATUS (AE_BAD_PARAMETER);
    
        if ((as = malloc(sizeof(*as), M_ACPISEM, M_NOWAIT | M_ZERO)) == NULL)
            return_ACPI_STATUS (AE_NO_MEMORY);
    
        mtx_init(&as->as_mtx, "ACPI semaphore", NULL, MTX_DEF);
        as->as_units = InitialUnits;
        as->as_maxunits = MaxUnits;
        as->as_pendings = as->as_resetting = as->as_timeouts = 0;
    
        ACPI_DEBUG_PRINT((ACPI_DB_MUTEX,
            "created semaphore %p max %d, initial %d\n", 
            as, InitialUnits, MaxUnits));
   
       *OutHandle = (ACPI_HANDLE)as;
   #else
       *OutHandle = (ACPI_HANDLE)OutHandle;
   #endif /* !ACPI_NO_SEMAPHORES */
   
       return_ACPI_STATUS (AE_OK);
   }
   
   ACPI_STATUS
   AcpiOsDeleteSemaphore(ACPI_HANDLE Handle)
   {
   #ifndef ACPI_NO_SEMAPHORES
       struct acpi_semaphore *as = (struct acpi_semaphore *)Handle;
   
       ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
   
       ACPI_DEBUG_PRINT((ACPI_DB_MUTEX, "destroyed semaphore %p\n", as));
       mtx_destroy(&as->as_mtx);
       free(Handle, M_ACPISEM);
   #endif /* !ACPI_NO_SEMAPHORES */
   
       return_ACPI_STATUS (AE_OK);
   }
   
   /*
    * This implementation has a bug, in that it has to stall for the entire
    * timeout before it will return AE_TIME.  A better implementation would
    * use getmicrotime() to correctly adjust the timeout after being woken up.
    */
   ACPI_STATUS
   AcpiOsWaitSemaphore(ACPI_HANDLE Handle, UINT32 Units, UINT16 Timeout)
   {
   #ifndef ACPI_NO_SEMAPHORES
       ACPI_STATUS                 result;
       struct acpi_semaphore       *as = (struct acpi_semaphore *)Handle;
       int                         rv, tmo;
       struct timeval              timeouttv, currenttv, timelefttv;
   
       ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
   
       if (as == NULL)
           return_ACPI_STATUS (AE_BAD_PARAMETER);
   
       if (cold)
           return_ACPI_STATUS (AE_OK);
   
   #if 0
       if (as->as_units < Units && as->as_timeouts > 10) {
           printf("%s: semaphore %p too many timeouts, resetting\n", __func__, as);
           AS_LOCK(as);
           as->as_units = as->as_maxunits;
           if (as->as_pendings)
               as->as_resetting = 1;
           as->as_timeouts = 0;
           wakeup(as);
           AS_UNLOCK(as);
           return_ACPI_STATUS (AE_TIME);
       }
   
       if (as->as_resetting)
           return_ACPI_STATUS (AE_TIME);
   #endif
   
       /* a timeout of ACPI_WAIT_FOREVER means "forever" */
       if (Timeout == ACPI_WAIT_FOREVER) {
           tmo = 0;
           timeouttv.tv_sec = ((0xffff/1000) + 1); /* cf. ACPI spec */
           timeouttv.tv_usec = 0;
       } else {
           /* compute timeout using microseconds per tick */
           tmo = (Timeout * 1000) / (1000000 / hz);
           if (tmo <= 0)
               tmo = 1;
           timeouttv.tv_sec  = Timeout / 1000;
           timeouttv.tv_usec = (Timeout % 1000) * 1000;
       }
   
       /* calculate timeout value in timeval */
       getmicrotime(&currenttv);
       timevaladd(&timeouttv, &currenttv);
   
       AS_LOCK(as);
       ACPI_DEBUG_PRINT((ACPI_DB_MUTEX,
           "get %d units from semaphore %p (has %d), timeout %d\n",
           Units, as, as->as_units, Timeout));
       for (;;) {
           if (as->as_maxunits == ACPI_NO_UNIT_LIMIT) {
               result = AE_OK;
               break;
           }
           if (as->as_units >= Units) {
               as->as_units -= Units;
               result = AE_OK;
               break;
           }
   
           /* limit number of pending treads */
           if (as->as_pendings >= ACPI_SEMAPHORES_MAX_PENDING) {
               result = AE_TIME;
               break;
           }
   
           /* if timeout values of zero is specified, return immediately */
           if (Timeout == 0) {
               result = AE_TIME;
               break;
           }
   
           ACPI_DEBUG_PRINT((ACPI_DB_MUTEX,
               "semaphore blocked, calling msleep(%p, %p, %d, \"acsem\", %d)\n",
               as, &as->as_mtx, PCATCH, tmo));
   
           as->as_pendings++;
   
           if (acpi_semaphore_debug) {
               printf("%s: Sleep %d, pending %d, semaphore %p, thread %d\n",
                   __func__, Timeout, as->as_pendings, as, AcpiOsGetThreadId());
           }
   
           rv = msleep(as, &as->as_mtx, PCATCH, "acsem", tmo);
   
           as->as_pendings--;
   
   #if 0
           if (as->as_resetting) {
               /* semaphore reset, return immediately */
               if (as->as_pendings == 0) {
                   as->as_resetting = 0;
               }
               result = AE_TIME;
               break;
           }
   #endif
   
           ACPI_DEBUG_PRINT((ACPI_DB_MUTEX, "msleep(%d) returned %d\n", tmo, rv));
           if (rv == EWOULDBLOCK) {
               result = AE_TIME;
               break;
           }
   
           /* check if we already awaited enough */
           timelefttv = timeouttv;
           getmicrotime(&currenttv);
           timevalsub(&timelefttv, &currenttv);
           if (timelefttv.tv_sec < 0) {
               ACPI_DEBUG_PRINT((ACPI_DB_MUTEX, "await semaphore %p timeout\n",
                   as));
               result = AE_TIME;
               break;
           }
   
           /* adjust timeout for the next sleep */
           tmo = (timelefttv.tv_sec * 1000000 + timelefttv.tv_usec) /
               (1000000 / hz);
           if (tmo <= 0)
               tmo = 1;
   
           if (acpi_semaphore_debug) {
               printf("%s: Wakeup timeleft(%lu, %lu), tmo %u, sem %p, thread %d\n",
                   __func__, timelefttv.tv_sec, timelefttv.tv_usec, tmo, as,
                   AcpiOsGetThreadId());
           }
       }
   
       if (acpi_semaphore_debug) {
           if (result == AE_TIME && Timeout > 0) {
               printf("%s: Timeout %d, pending %d, semaphore %p\n",
                   __func__, Timeout, as->as_pendings, as);
           }
           if (result == AE_OK && (as->as_timeouts > 0 || as->as_pendings > 0)) {
               printf("%s: Acquire %d, units %d, pending %d, sem %p, thread %d\n",
                   __func__, Units, as->as_units, as->as_pendings, as,
                   AcpiOsGetThreadId());
           }
       }
   
       if (result == AE_TIME)
           as->as_timeouts++;
       else
           as->as_timeouts = 0;
   
       AS_UNLOCK(as);
       return_ACPI_STATUS (result);
   #else
       return_ACPI_STATUS (AE_OK);
   #endif /* !ACPI_NO_SEMAPHORES */
   }
   
   ACPI_STATUS
   AcpiOsSignalSemaphore(ACPI_HANDLE Handle, UINT32 Units)
   {
   #ifndef ACPI_NO_SEMAPHORES
       struct acpi_semaphore       *as = (struct acpi_semaphore *)Handle;
   
       ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
   
       if (as == NULL)
           return_ACPI_STATUS(AE_BAD_PARAMETER);
   
       AS_LOCK(as);
       ACPI_DEBUG_PRINT((ACPI_DB_MUTEX,
           "return %d units to semaphore %p (has %d)\n",
           Units, as, as->as_units));
       if (as->as_maxunits != ACPI_NO_UNIT_LIMIT) {
           as->as_units += Units;
           if (as->as_units > as->as_maxunits)
               as->as_units = as->as_maxunits;
       }
   
       if (acpi_semaphore_debug && (as->as_timeouts > 0 || as->as_pendings > 0)) {
           printf("%s: Release %d, units %d, pending %d, semaphore %p, thread %d\n",
               __func__, Units, as->as_units, as->as_pendings, as, AcpiOsGetThreadId());
       }
   
       wakeup(as);
       AS_UNLOCK(as);
   #endif /* !ACPI_NO_SEMAPHORES */
   
       return_ACPI_STATUS (AE_OK);
   }
   
   ACPI_STATUS
   AcpiOsCreateLock (ACPI_HANDLE *OutHandle)
   {
       struct mtx *m;
   
       if (OutHandle == NULL)
           return (AE_BAD_PARAMETER);
       m = malloc(sizeof(*m), M_ACPISEM, M_NOWAIT | M_ZERO);
       if (m == NULL)
           return (AE_NO_MEMORY);
   
       mtx_init(m, "acpica subsystem lock", NULL, MTX_DEF);
       *OutHandle = (ACPI_HANDLE)m;
       return (AE_OK);
   }
   
   void
   AcpiOsDeleteLock (ACPI_HANDLE Handle)
   {
       struct mtx *m = (struct mtx *)Handle;
   
       if (Handle == NULL)
           return;
       mtx_destroy(m);
   }
   
   /*
    * The Flags parameter seems to state whether or not caller is an ISR
    * (and thus can't block) but since we have ithreads, we don't worry
    * about potentially blocking.
    */
   void
   AcpiOsAcquireLock (ACPI_HANDLE Handle, UINT32 Flags)
   {
       struct mtx *m = (struct mtx *)Handle;
   
       if (Handle == NULL)
           return;
       mtx_lock(m);
   }
   
   void
   AcpiOsReleaseLock (ACPI_HANDLE Handle, UINT32 Flags)
   {
       struct mtx *m = (struct mtx *)Handle;
   
       if (Handle == NULL)
           return;
       mtx_unlock(m);
   }
   
   /* Section 5.2.9.1:  global lock acquire/release functions */
   #define GL_ACQUIRED     (-1)
   #define GL_BUSY         0
   #define GL_BIT_PENDING  0x1
   #define GL_BIT_OWNED    0x2
   #define GL_BIT_MASK     (GL_BIT_PENDING | GL_BIT_OWNED)
   
   /*
    * Acquire the global lock.  If busy, set the pending bit.  The caller
    * will wait for notification from the BIOS that the lock is available
    * and then attempt to acquire it again.
    */
   int
   acpi_acquire_global_lock(uint32_t *lock)
   {
           uint32_t new, old;
   
           do {
                   old = *lock;
                   new = ((old & ~GL_BIT_MASK) | GL_BIT_OWNED) |
                           ((old >> 1) & GL_BIT_PENDING);
           } while (atomic_cmpset_acq_int(lock, old, new) == 0);
   
           return ((new < GL_BIT_MASK) ? GL_ACQUIRED : GL_BUSY);
   }
   
   /*
    * Release the global lock, returning whether there is a waiter pending.
    * If the BIOS set the pending bit, OSPM must notify the BIOS when it
    * releases the lock.
    */
   int
   acpi_release_global_lock(uint32_t *lock)
   {
           uint32_t new, old;
   
           do {
                   old = *lock;
                   new = old & ~GL_BIT_MASK;
           } while (atomic_cmpset_rel_int(lock, old, new) == 0);
   
           return (old & GL_BIT_PENDING);
   }

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