FreeBSD/Linux Kernel Cross Reference
sys/dev/acpica/acpi_cpu_cstate.c

     /*-
      * Copyright (c) 2003-2005 Nate Lawson (SDG)
      * Copyright (c) 2001 Michael Smith
      * 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: src/sys/dev/acpica/acpi_cpu.c,v 1.72 2008/04/12 12:06:00 rpaulo Exp $
     */
    
    #include "opt_acpi.h"
    #include <sys/param.h>
    #include <sys/bus.h>
    #include <sys/kernel.h>
    #include <sys/malloc.h>
    #include <sys/globaldata.h>
    #include <sys/power.h>
    #include <sys/proc.h>
    #include <sys/sbuf.h>
    #include <sys/thread2.h>
    #include <sys/mplock2.h>
    
    #include <bus/pci/pcivar.h>
    #include <machine/atomic.h>
    #include <machine/globaldata.h>
    #include <machine/md_var.h>
    #include <machine/smp.h>
    #include <sys/rman.h>
    
    #include "acpi.h"
    #include "acpivar.h"
    #include "acpi_cpu.h"
    
    /*
     * Support for ACPI Processor devices, including C[1-3] sleep states.
     */
    
    /* Hooks for the ACPI CA debugging infrastructure */
    #define _COMPONENT      ACPI_PROCESSOR
    ACPI_MODULE_NAME("PROCESSOR")
    
    struct acpi_cx {
        struct resource     *p_lvlx;        /* Register to read to enter state. */
        int                  rid;           /* rid of p_lvlx */
        uint32_t             type;          /* C1-3 (C4 and up treated as C3). */
        uint32_t             trans_lat;     /* Transition latency (usec). */
        uint32_t             power;         /* Power consumed (mW). */
        int                  res_type;      /* Resource type for p_lvlx. */
    };
    #define MAX_CX_STATES    8
    
    struct acpi_cpu_softc {
        device_t             cpu_dev;
        struct acpi_cpux_softc *cpu_parent;
        ACPI_HANDLE          cpu_handle;
        struct mdglobaldata *md;
        uint32_t             cpu_acpi_id;   /* ACPI processor id */
        uint32_t             cpu_p_blk;     /* ACPI P_BLK location */
        uint32_t             cpu_p_blk_len; /* P_BLK length (must be 6). */
        struct acpi_cx       cpu_cx_states[MAX_CX_STATES];
        int                  cpu_cx_count;  /* Number of valid Cx states. */
        int                  cpu_prev_sleep;/* Last idle sleep duration. */
        /* Runtime state. */
        int                  cpu_non_c3;    /* Index of lowest non-C3 state. */
        u_int                cpu_cx_stats[MAX_CX_STATES];/* Cx usage history. */
        /* Values for sysctl. */
        int                  cpu_cx_lowest;
        char                 cpu_cx_supported[64];
    };
    
    struct acpi_cpu_device {
        struct resource_list        ad_rl;
    };
    
    #define CPU_GET_REG(reg, width)                                         \
        (bus_space_read_ ## width(rman_get_bustag((reg)),                   \
                          rman_get_bushandle((reg)), 0))
    #define CPU_SET_REG(reg, width, val)                                    \
        (bus_space_write_ ## width(rman_get_bustag((reg)),                  \
                           rman_get_bushandle((reg)), 0, (val)))
   
   #define PM_USEC(x)       ((x) >> 2)     /* ~4 clocks per usec (3.57955 Mhz) */
   
   #define ACPI_NOTIFY_CX_STATES   0x81    /* _CST changed. */
   
   #define CPU_QUIRK_NO_C3         (1<<0)  /* C3-type states are not usable. */
   #define CPU_QUIRK_NO_BM_CTRL    (1<<2)  /* No bus mastering control. */
   
   #define PCI_VENDOR_INTEL        0x8086
   #define PCI_DEVICE_82371AB_3    0x7113  /* PIIX4 chipset for quirks. */
   #define PCI_REVISION_A_STEP     0
   #define PCI_REVISION_B_STEP     1
   #define PCI_REVISION_4E         2
   #define PCI_REVISION_4M         3
   #define PIIX4_DEVACTB_REG       0x58
   #define PIIX4_BRLD_EN_IRQ0      (1<<0)
   #define PIIX4_BRLD_EN_IRQ       (1<<1)
   #define PIIX4_BRLD_EN_IRQ8      (1<<5)
   #define PIIX4_STOP_BREAK_MASK   (PIIX4_BRLD_EN_IRQ0 | PIIX4_BRLD_EN_IRQ | PIIX4_BRLD_EN_IRQ8)
   #define PIIX4_PCNTRL_BST_EN     (1<<10)
   
   /* Platform hardware resource information. */
   static uint32_t          cpu_smi_cmd;   /* Value to write to SMI_CMD. */
   static uint8_t           cpu_cst_cnt;   /* Indicate we are _CST aware. */
   static int               cpu_quirks;    /* Indicate any hardware bugs. */
   
   /* Runtime state. */
   static int               cpu_disable_idle; /* Disable entry to idle function */
   static int               cpu_cx_count;  /* Number of valid Cx states */
   
   /* Values for sysctl. */
   static int               cpu_cx_generic;
   static int               cpu_cx_lowest;
   
   /* C3 state transition */
   static int               cpu_c3_ncpus;
   
   static device_t         *cpu_devices;
   static int               cpu_ndevices;
   static struct acpi_cpu_softc **cpu_softc;
   
   static int      acpi_cpu_cst_probe(device_t dev);
   static int      acpi_cpu_cst_attach(device_t dev);
   static int      acpi_cpu_cst_suspend(device_t dev);
   static int      acpi_cpu_cst_resume(device_t dev);
   static struct resource_list *acpi_cpu_cst_get_rlist(device_t dev,
                       device_t child);
   static device_t acpi_cpu_cst_add_child(device_t bus, device_t parent,
                       int order, const char *name, int unit);
   static int      acpi_cpu_cst_read_ivar(device_t dev, device_t child,
                       int index, uintptr_t *result);
   static int      acpi_cpu_cst_shutdown(device_t dev);
   static void     acpi_cpu_cx_probe(struct acpi_cpu_softc *sc);
   static void     acpi_cpu_generic_cx_probe(struct acpi_cpu_softc *sc);
   static int      acpi_cpu_cx_cst(struct acpi_cpu_softc *sc);
   static void     acpi_cpu_startup(void *arg);
   static void     acpi_cpu_startup_cx(struct acpi_cpu_softc *sc);
   static void     acpi_cpu_cx_list(struct acpi_cpu_softc *sc);
   static void     acpi_cpu_idle(void);
   static void     acpi_cpu_cst_notify(device_t);
   static int      acpi_cpu_quirks(void);
   static int      acpi_cpu_usage_sysctl(SYSCTL_HANDLER_ARGS);
   static int      acpi_cpu_set_cx_lowest(struct acpi_cpu_softc *sc, int val);
   static int      acpi_cpu_cx_lowest_sysctl(SYSCTL_HANDLER_ARGS);
   static int      acpi_cpu_global_cx_lowest_sysctl(SYSCTL_HANDLER_ARGS);
   
   static void     acpi_cpu_c1(void);      /* XXX */
   
   static device_method_t acpi_cpu_cst_methods[] = {
       /* Device interface */
       DEVMETHOD(device_probe,     acpi_cpu_cst_probe),
       DEVMETHOD(device_attach,    acpi_cpu_cst_attach),
       DEVMETHOD(device_detach,    bus_generic_detach),
       DEVMETHOD(device_shutdown,  acpi_cpu_cst_shutdown),
       DEVMETHOD(device_suspend,   acpi_cpu_cst_suspend),
       DEVMETHOD(device_resume,    acpi_cpu_cst_resume),
   
       /* Bus interface */
       DEVMETHOD(bus_add_child,    acpi_cpu_cst_add_child),
       DEVMETHOD(bus_read_ivar,    acpi_cpu_cst_read_ivar),
       DEVMETHOD(bus_get_resource_list, acpi_cpu_cst_get_rlist),
       DEVMETHOD(bus_get_resource, bus_generic_rl_get_resource),
       DEVMETHOD(bus_set_resource, bus_generic_rl_set_resource),
       DEVMETHOD(bus_alloc_resource, bus_generic_rl_alloc_resource),
       DEVMETHOD(bus_release_resource, bus_generic_rl_release_resource),
       DEVMETHOD(bus_driver_added, bus_generic_driver_added),
       DEVMETHOD(bus_activate_resource, bus_generic_activate_resource),
       DEVMETHOD(bus_deactivate_resource, bus_generic_deactivate_resource),
       DEVMETHOD(bus_setup_intr,   bus_generic_setup_intr),
       DEVMETHOD(bus_teardown_intr, bus_generic_teardown_intr),
       DEVMETHOD_END
   };
   
   static driver_t acpi_cpu_cst_driver = {
       "cpu_cst",
       acpi_cpu_cst_methods,
       sizeof(struct acpi_cpu_softc),
   };
   
   static devclass_t acpi_cpu_cst_devclass;
   DRIVER_MODULE(cpu_cst, cpu, acpi_cpu_cst_driver, acpi_cpu_cst_devclass, NULL, NULL);
   MODULE_DEPEND(cpu_cst, acpi, 1, 1, 1);
   
   static int
   acpi_cpu_cst_probe(device_t dev)
   {
       int cpu_id;
   
       if (acpi_disabled("cpu_cst") || acpi_get_type(dev) != ACPI_TYPE_PROCESSOR)
           return (ENXIO);
   
       cpu_id = acpi_get_magic(dev);
   
       if (cpu_softc == NULL)
           cpu_softc = kmalloc(sizeof(struct acpi_cpu_softc *) *
               SMP_MAXCPU, M_TEMP /* XXX */, M_INTWAIT | M_ZERO);
   
       /*
        * Check if we already probed this processor.  We scan the bus twice
        * so it's possible we've already seen this one.
        */
       if (cpu_softc[cpu_id] != NULL) {
           device_printf(dev, "CPU%d cstate already exist\n", cpu_id);
           return (ENXIO);
       }
   
       /* Mark this processor as in-use and save our derived id for attach. */
       cpu_softc[cpu_id] = (void *)1;
       device_set_desc(dev, "ACPI CPU C-State");
   
       return (0);
   }
   
   static int
   acpi_cpu_cst_attach(device_t dev)
   {
       ACPI_BUFFER            buf;
       ACPI_OBJECT            *obj;
       struct mdglobaldata   *md;
       struct acpi_cpu_softc *sc;
       ACPI_STATUS            status;
       int                    cpu_id;
   
       ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
   
       sc = device_get_softc(dev);
       sc->cpu_dev = dev;
       sc->cpu_parent = device_get_softc(device_get_parent(dev));
       sc->cpu_handle = acpi_get_handle(dev);
       cpu_id = acpi_get_magic(dev);
       cpu_softc[cpu_id] = sc;
       md = (struct mdglobaldata *)globaldata_find(device_get_unit(dev));
       sc->md = md;
       cpu_smi_cmd = AcpiGbl_FADT.SmiCommand;
       cpu_cst_cnt = AcpiGbl_FADT.CstControl;
   
       buf.Pointer = NULL;
       buf.Length = ACPI_ALLOCATE_BUFFER;
       status = AcpiEvaluateObject(sc->cpu_handle, NULL, NULL, &buf);
       if (ACPI_FAILURE(status)) {
           device_printf(dev, "attach failed to get Processor obj - %s\n",
                         AcpiFormatException(status));
           return (ENXIO);
       }
       obj = (ACPI_OBJECT *)buf.Pointer;
       sc->cpu_p_blk = obj->Processor.PblkAddress;
       sc->cpu_p_blk_len = obj->Processor.PblkLength;
       sc->cpu_acpi_id = obj->Processor.ProcId;
       AcpiOsFree(obj);
       ACPI_DEBUG_PRINT((ACPI_DB_INFO, "acpi_cpu%d: P_BLK at %#x/%d\n",
                        device_get_unit(dev), sc->cpu_p_blk, sc->cpu_p_blk_len));
   
       /*
        * If this is the first cpu we attach, create and initialize the generic
        * resources that will be used by all acpi cpu devices.
        */
       if (device_get_unit(dev) == 0) {
           /* Assume we won't be using generic Cx mode by default */
           cpu_cx_generic = FALSE;
   
           /* Queue post cpu-probing task handler */
           AcpiOsExecute(OSL_NOTIFY_HANDLER, acpi_cpu_startup, NULL);
       }
   
       /* Probe for Cx state support. */
       acpi_cpu_cx_probe(sc);
   
       /* Finally,  call identify and probe/attach for child devices. */
       bus_generic_probe(dev);
       bus_generic_attach(dev);
   
       return (0);
   }
   
   /*
    * Disable any entry to the idle function during suspend and re-enable it
    * during resume.
    */
   static int
   acpi_cpu_cst_suspend(device_t dev)
   {
       int error;
   
       error = bus_generic_suspend(dev);
       if (error)
           return (error);
       cpu_disable_idle = TRUE;
       return (0);
   }
   
   static int
   acpi_cpu_cst_resume(device_t dev)
   {
   
       cpu_disable_idle = FALSE;
       return (bus_generic_resume(dev));
   }
   
   static struct resource_list *
   acpi_cpu_cst_get_rlist(device_t dev, device_t child)
   {
       struct acpi_cpu_device *ad;
   
       ad = device_get_ivars(child);
       if (ad == NULL)
           return (NULL);
       return (&ad->ad_rl);
   }
   
   static device_t
   acpi_cpu_cst_add_child(device_t bus, device_t parent, int order,
       const char *name, int unit)
   {
       struct acpi_cpu_device *ad;
       device_t child;
   
       if ((ad = kmalloc(sizeof(*ad), M_TEMP, M_NOWAIT | M_ZERO)) == NULL)
           return (NULL);
   
       resource_list_init(&ad->ad_rl);
   
       child = device_add_child_ordered(parent, order, name, unit);
       if (child != NULL)
           device_set_ivars(child, ad);
       else
           kfree(ad, M_TEMP);
       return (child);
   }
   
   static int
   acpi_cpu_cst_read_ivar(device_t dev, device_t child, int index,
       uintptr_t *result)
   {
       struct acpi_cpu_softc *sc;
   
       sc = device_get_softc(dev);
       switch (index) {
       case ACPI_IVAR_HANDLE:
           *result = (uintptr_t)sc->cpu_handle;
           break;
   #if 0
       case CPU_IVAR_PCPU:
           *result = (uintptr_t)sc->cpu_pcpu;
           break;
   #endif
       default:
           return (ENOENT);
       }
       return (0);
   }
   
   static int
   acpi_cpu_cst_shutdown(device_t dev)
   {
       ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
   
       /* Allow children to shutdown first. */
       bus_generic_shutdown(dev);
   
       /*
        * Disable any entry to the idle function.  There is a small race where
        * an idle thread have passed this check but not gone to sleep.  This
        * is ok since device_shutdown() does not free the softc, otherwise
        * we'd have to be sure all threads were evicted before returning.
        */
       cpu_disable_idle = TRUE;
   
       return_VALUE (0);
   }
   
   static void
   acpi_cpu_cx_probe(struct acpi_cpu_softc *sc)
   {
       ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
   
       /* Use initial sleep value of 1 sec. to start with lowest idle state. */
       sc->cpu_prev_sleep = 1000000;
       sc->cpu_cx_lowest = 0;
   
       /*
        * Check for the ACPI 2.0 _CST sleep states object. If we can't find
        * any, we'll revert to generic FADT/P_BLK Cx control method which will
        * be handled by acpi_cpu_startup. We need to defer to after having
        * probed all the cpus in the system before probing for generic Cx
        * states as we may already have found cpus with valid _CST packages
        */
       if (!cpu_cx_generic && acpi_cpu_cx_cst(sc) != 0) {
           /*
            * We were unable to find a _CST package for this cpu or there
            * was an error parsing it. Switch back to generic mode.
            */
           cpu_cx_generic = TRUE;
           if (bootverbose)
               device_printf(sc->cpu_dev, "switching to generic Cx mode\n");
       }
   
       /*
        * TODO: _CSD Package should be checked here.
        */
   }
   
   static void
   acpi_cpu_generic_cx_probe(struct acpi_cpu_softc *sc)
   {
       ACPI_GENERIC_ADDRESS         gas;
       struct acpi_cx              *cx_ptr;
   
       sc->cpu_cx_count = 0;
       cx_ptr = sc->cpu_cx_states;
   
       /* Use initial sleep value of 1 sec. to start with lowest idle state. */
       sc->cpu_prev_sleep = 1000000;
   
       /* C1 has been required since just after ACPI 1.0 */
       cx_ptr->type = ACPI_STATE_C1;
       cx_ptr->trans_lat = 0;
       cx_ptr++;
       sc->cpu_cx_count++;
   
       /* 
        * The spec says P_BLK must be 6 bytes long.  However, some systems
        * use it to indicate a fractional set of features present so we
        * take 5 as C2.  Some may also have a value of 7 to indicate
        * another C3 but most use _CST for this (as required) and having
        * "only" C1-C3 is not a hardship.
        */
       if (sc->cpu_p_blk_len < 5)
           return; 
   
       /* Validate and allocate resources for C2 (P_LVL2). */
       gas.SpaceId = ACPI_ADR_SPACE_SYSTEM_IO;
       gas.BitWidth = 8;
       if (AcpiGbl_FADT.C2Latency <= 100) {
           gas.Address = sc->cpu_p_blk + 4;
   
           cx_ptr->rid = sc->cpu_parent->cpux_next_rid;
           acpi_bus_alloc_gas(sc->cpu_dev, &cx_ptr->type, &cx_ptr->rid, &gas, &cx_ptr->p_lvlx,
                                               RF_SHAREABLE);
           if (cx_ptr->p_lvlx != NULL) {
               sc->cpu_parent->cpux_next_rid++;
               cx_ptr->type = ACPI_STATE_C2;
               cx_ptr->trans_lat = AcpiGbl_FADT.C2Latency;
               cx_ptr++;
               sc->cpu_cx_count++;
           }
       }
       if (sc->cpu_p_blk_len < 6)
           return;
   
       /* Validate and allocate resources for C3 (P_LVL3). */
       if (AcpiGbl_FADT.C3Latency <= 1000 && !(cpu_quirks & CPU_QUIRK_NO_C3)) {
           gas.Address = sc->cpu_p_blk + 5;
   
           cx_ptr->rid = sc->cpu_parent->cpux_next_rid;
           acpi_bus_alloc_gas(sc->cpu_dev, &cx_ptr->type, &cx_ptr->rid, &gas,
                                               &cx_ptr->p_lvlx, RF_SHAREABLE);
           if (cx_ptr->p_lvlx != NULL) {
               sc->cpu_parent->cpux_next_rid++;
               cx_ptr->type = ACPI_STATE_C3;
               cx_ptr->trans_lat = AcpiGbl_FADT.C3Latency;
               cx_ptr++;
               sc->cpu_cx_count++;
           }
       }
   }
   
   /*
    * Parse a _CST package and set up its Cx states.  Since the _CST object
    * can change dynamically, our notify handler may call this function
    * to clean up and probe the new _CST package.
    */
   static int
   acpi_cpu_cx_cst(struct acpi_cpu_softc *sc)
   {
       struct       acpi_cx *cx_ptr;
       ACPI_STATUS  status;
       ACPI_BUFFER  buf;
       ACPI_OBJECT *top;
       ACPI_OBJECT *pkg;
       uint32_t     count;
       int          i;
   
       ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
   
       buf.Pointer = NULL;
       buf.Length = ACPI_ALLOCATE_BUFFER;
       status = AcpiEvaluateObject(sc->cpu_handle, "_CST", NULL, &buf);
       if (ACPI_FAILURE(status))
           return (ENXIO);
   
       /* _CST is a package with a count and at least one Cx package. */
       top = (ACPI_OBJECT *)buf.Pointer;
       if (!ACPI_PKG_VALID(top, 2) || acpi_PkgInt32(top, 0, &count) != 0) {
           device_printf(sc->cpu_dev, "invalid _CST package\n");
           AcpiOsFree(buf.Pointer);
           return (ENXIO);
       }
       if (count != top->Package.Count - 1) {
           device_printf(sc->cpu_dev, "invalid _CST state count (%d != %d)\n",
                  count, top->Package.Count - 1);
           count = top->Package.Count - 1;
       }
       if (count > MAX_CX_STATES) {
           device_printf(sc->cpu_dev, "_CST has too many states (%d)\n", count);
           count = MAX_CX_STATES;
       }
   
       /* Set up all valid states. */
       sc->cpu_cx_count = 0;
       cx_ptr = sc->cpu_cx_states;
       for (i = 0; i < count; i++) {
           pkg = &top->Package.Elements[i + 1];
           if (!ACPI_PKG_VALID(pkg, 4) ||
               acpi_PkgInt32(pkg, 1, &cx_ptr->type) != 0 ||
               acpi_PkgInt32(pkg, 2, &cx_ptr->trans_lat) != 0 ||
               acpi_PkgInt32(pkg, 3, &cx_ptr->power) != 0) {
   
               device_printf(sc->cpu_dev, "skipping invalid Cx state package\n");
               continue;
           }
   
           /* Validate the state to see if we should use it. */
           switch (cx_ptr->type) {
           case ACPI_STATE_C1:
               sc->cpu_non_c3 = i;
               cx_ptr++;
               sc->cpu_cx_count++;
               continue;
           case ACPI_STATE_C2:
               sc->cpu_non_c3 = i;
               break;
           case ACPI_STATE_C3:
           default:
               if ((cpu_quirks & CPU_QUIRK_NO_C3) != 0) {
   
                   ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                    "acpi_cpu%d: C3[%d] not available.\n",
                                    device_get_unit(sc->cpu_dev), i));
                   continue;
               }
               break;
           }
   
   #ifdef notyet
           /* Free up any previous register. */
           if (cx_ptr->p_lvlx != NULL) {
               bus_release_resource(sc->cpu_dev, 0, 0, cx_ptr->p_lvlx);
               cx_ptr->p_lvlx = NULL;
           }
   #endif
   
           /* Allocate the control register for C2 or C3. */
           cx_ptr->rid = sc->cpu_parent->cpux_next_rid;
           acpi_PkgGas(sc->cpu_dev, pkg, 0, &cx_ptr->res_type, &cx_ptr->rid, &cx_ptr->p_lvlx,
                       RF_SHAREABLE);
           if (cx_ptr->p_lvlx) {
               sc->cpu_parent->cpux_next_rid++;
               ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                "acpi_cpu%d: Got C%d - %d latency\n",
                                device_get_unit(sc->cpu_dev), cx_ptr->type,
                                cx_ptr->trans_lat));
               cx_ptr++;
               sc->cpu_cx_count++;
           }
       }
       AcpiOsFree(buf.Pointer);
   
       return (0);
   }
   
   /*
    * Call this *after* all CPUs have been attached.
    */
   static void
   acpi_cpu_startup(void *arg)
   {
       struct acpi_cpu_softc *sc;
       int i;
   
       /* Get set of CPU devices */
       devclass_get_devices(acpi_cpu_cst_devclass, &cpu_devices, &cpu_ndevices);
   
       /*
        * Setup any quirks that might necessary now that we have probed
        * all the CPUs
        */
       acpi_cpu_quirks();
   
       cpu_cx_count = 0;
       if (cpu_cx_generic) {
           /*
            * We are using generic Cx mode, probe for available Cx states
            * for all processors.
            */
           for (i = 0; i < cpu_ndevices; i++) {
               sc = device_get_softc(cpu_devices[i]);
               acpi_cpu_generic_cx_probe(sc);
               if (sc->cpu_cx_count > cpu_cx_count)
                       cpu_cx_count = sc->cpu_cx_count;
           }
   
           /*
            * Find the highest Cx state common to all CPUs
            * in the system, taking quirks into account.
            */
           for (i = 0; i < cpu_ndevices; i++) {
               sc = device_get_softc(cpu_devices[i]);
               if (sc->cpu_cx_count < cpu_cx_count)
                   cpu_cx_count = sc->cpu_cx_count;
           }
       } else {
           /*
            * We are using _CST mode, remove C3 state if necessary.
            * Update the largest Cx state supported in the global cpu_cx_count.
            * It will be used in the global Cx sysctl handler.
            * As we now know for sure that we will be using _CST mode
            * install our notify handler.
            */
           for (i = 0; i < cpu_ndevices; i++) {
               sc = device_get_softc(cpu_devices[i]);
               if (cpu_quirks & CPU_QUIRK_NO_C3) {
                   sc->cpu_cx_count = sc->cpu_non_c3 + 1;
               }
               if (sc->cpu_cx_count > cpu_cx_count)
                   cpu_cx_count = sc->cpu_cx_count;
               sc->cpu_parent->cpux_cst_notify = acpi_cpu_cst_notify;
           }
       }
   
       /* Perform Cx final initialization. */
       for (i = 0; i < cpu_ndevices; i++) {
           sc = device_get_softc(cpu_devices[i]);
           acpi_cpu_startup_cx(sc);
   
           if (sc->cpu_parent->glob_sysctl_tree != NULL) {
               struct acpi_cpux_softc *cpux = sc->cpu_parent;
   
               /* Add a sysctl handler to handle global Cx lowest setting */
               SYSCTL_ADD_PROC(&cpux->glob_sysctl_ctx,
                               SYSCTL_CHILDREN(cpux->glob_sysctl_tree),
                               OID_AUTO, "cx_lowest",
                               CTLTYPE_STRING | CTLFLAG_RW, NULL, 0,
                               acpi_cpu_global_cx_lowest_sysctl, "A",
                               "Global lowest Cx sleep state to use");
           }
       }
   
       /* Take over idling from cpu_idle_default(). */
       cpu_cx_lowest = 0;
       cpu_disable_idle = FALSE;
       cpu_idle_hook = acpi_cpu_idle;
   }
   
   static void
   acpi_cpu_cx_list(struct acpi_cpu_softc *sc)
   {
       struct sbuf sb;
       int i;
   
       /*
        * Set up the list of Cx states
        */
       sc->cpu_non_c3 = 0;
       sbuf_new(&sb, sc->cpu_cx_supported, sizeof(sc->cpu_cx_supported),
           SBUF_FIXEDLEN);
       for (i = 0; i < sc->cpu_cx_count; i++) {
           sbuf_printf(&sb, "C%d/%d ", i + 1, sc->cpu_cx_states[i].trans_lat);
           if (sc->cpu_cx_states[i].type < ACPI_STATE_C3)
               sc->cpu_non_c3 = i;
       }
       sbuf_trim(&sb);
       sbuf_finish(&sb);
   }       
   
   static void
   acpi_cpu_startup_cx(struct acpi_cpu_softc *sc)
   {
       struct acpi_cpux_softc *cpux = sc->cpu_parent;
   
       acpi_cpu_cx_list(sc);
       
       SYSCTL_ADD_STRING(&cpux->pcpu_sysctl_ctx,
                         SYSCTL_CHILDREN(cpux->pcpu_sysctl_tree),
                         OID_AUTO, "cx_supported", CTLFLAG_RD,
                         sc->cpu_cx_supported, 0,
                         "Cx/microsecond values for supported Cx states");
       SYSCTL_ADD_PROC(&cpux->pcpu_sysctl_ctx,
                       SYSCTL_CHILDREN(cpux->pcpu_sysctl_tree),
                       OID_AUTO, "cx_lowest", CTLTYPE_STRING | CTLFLAG_RW,
                       (void *)sc, 0, acpi_cpu_cx_lowest_sysctl, "A",
                       "lowest Cx sleep state to use");
       SYSCTL_ADD_PROC(&cpux->pcpu_sysctl_ctx,
                       SYSCTL_CHILDREN(cpux->pcpu_sysctl_tree),
                       OID_AUTO, "cx_usage", CTLTYPE_STRING | CTLFLAG_RD,
                       (void *)sc, 0, acpi_cpu_usage_sysctl, "A",
                       "percent usage for each Cx state");
   
   #ifdef notyet
       /* Signal platform that we can handle _CST notification. */
       if (!cpu_cx_generic && cpu_cst_cnt != 0) {
           ACPI_LOCK(acpi);
           AcpiOsWritePort(cpu_smi_cmd, cpu_cst_cnt, 8);
           ACPI_UNLOCK(acpi);
       }
   #endif
   }
   
   /*
    * Idle the CPU in the lowest state possible.  This function is called with
    * interrupts disabled.  Note that once it re-enables interrupts, a task
    * switch can occur so do not access shared data (i.e. the softc) after
    * interrupts are re-enabled.
    */
   static void
   acpi_cpu_idle(void)
   {
       struct      acpi_cpu_softc *sc;
       struct      acpi_cx *cx_next;
       uint64_t    start_time, end_time;
       int         bm_active, cx_next_idx, i;
   
       /* If disabled, return immediately. */
       if (cpu_disable_idle) {
           ACPI_ENABLE_IRQS();
           return;
       }
   
       /*
        * Look up our CPU id to get our softc.  If it's NULL, we'll use C1
        * since there is no ACPI processor object for this CPU.  This occurs
        * for logical CPUs in the HTT case.
        */
       sc = cpu_softc[mdcpu->mi.gd_cpuid];
       if (sc == NULL) {
           acpi_cpu_c1();
           return;
       }
   
       /* Find the lowest state that has small enough latency. */
       cx_next_idx = 0;
       for (i = sc->cpu_cx_lowest; i >= 0; i--) {
           if (sc->cpu_cx_states[i].trans_lat * 3 <= sc->cpu_prev_sleep) {
               cx_next_idx = i;
               break;
           }
       }
   
       /*
        * Check for bus master activity.  If there was activity, clear
        * the bit and use the lowest non-C3 state.  Note that the USB
        * driver polling for new devices keeps this bit set all the
        * time if USB is loaded.
        */
       if ((cpu_quirks & CPU_QUIRK_NO_BM_CTRL) == 0) {
           AcpiReadBitRegister(ACPI_BITREG_BUS_MASTER_STATUS, &bm_active);
           if (bm_active != 0) {
               AcpiWriteBitRegister(ACPI_BITREG_BUS_MASTER_STATUS, 1);
               cx_next_idx = min(cx_next_idx, sc->cpu_non_c3);
           }
       }
   
       /* Select the next state and update statistics. */
       cx_next = &sc->cpu_cx_states[cx_next_idx];
       sc->cpu_cx_stats[cx_next_idx]++;
       KASSERT(cx_next->type != ACPI_STATE_C0, ("acpi_cpu_idle: C0 sleep"));
   
       /*
        * Execute HLT (or equivalent) and wait for an interrupt.  We can't
        * calculate the time spent in C1 since the place we wake up is an
        * ISR.  Assume we slept half of quantum and return.
        */
       if (cx_next->type == ACPI_STATE_C1) {
           sc->cpu_prev_sleep = (sc->cpu_prev_sleep * 3 + 500000 / hz) / 4;
           acpi_cpu_c1();
           return;
       }
   
       /*
        * For C3, disable bus master arbitration and enable bus master wake
        * if BM control is available, otherwise flush the CPU cache.
        */
       if (cx_next->type == ACPI_STATE_C3) {
           if ((cpu_quirks & CPU_QUIRK_NO_BM_CTRL) == 0) {
               AcpiWriteBitRegister(ACPI_BITREG_ARB_DISABLE, 1);
               AcpiWriteBitRegister(ACPI_BITREG_BUS_MASTER_RLD, 1);
           } else
               ACPI_FLUSH_CPU_CACHE();
       }
   
       /*
        * Read from P_LVLx to enter C2(+), checking time spent asleep.
        * Use the ACPI timer for measuring sleep time.  Since we need to
        * get the time very close to the CPU start/stop clock logic, this
        * is the only reliable time source.
        */
       AcpiRead(&start_time, &AcpiGbl_FADT.XPmTimerBlock);
       CPU_GET_REG(cx_next->p_lvlx, 1);
   
       /*
        * Read the end time twice.  Since it may take an arbitrary time
        * to enter the idle state, the first read may be executed before
        * the processor has stopped.  Doing it again provides enough
        * margin that we are certain to have a correct value.
        */
       AcpiRead(&end_time, &AcpiGbl_FADT.XPmTimerBlock);
       AcpiRead(&end_time, &AcpiGbl_FADT.XPmTimerBlock);
   
       /* Enable bus master arbitration and disable bus master wakeup. */
       if (cx_next->type == ACPI_STATE_C3) {
           if ((cpu_quirks & CPU_QUIRK_NO_BM_CTRL) == 0) {
               AcpiWriteBitRegister(ACPI_BITREG_ARB_DISABLE, 0);
               AcpiWriteBitRegister(ACPI_BITREG_BUS_MASTER_RLD, 0);
           }
       }
       ACPI_ENABLE_IRQS();
   
       /* Find the actual time asleep in microseconds. */
       end_time = acpi_TimerDelta(end_time, start_time);
       sc->cpu_prev_sleep = (sc->cpu_prev_sleep * 3 + PM_USEC(end_time)) / 4;
   }
   
   /*
    * Re-evaluate the _CST object when we are notified that it changed.
    *
    * XXX Re-evaluation disabled until locking is done.
    */
   static void
   acpi_cpu_cst_notify(device_t dev)
   {
       struct acpi_cpu_softc *sc = device_get_softc(dev);
       struct acpi_cpu_softc *isc;
       int i;
       
       /* Update the list of Cx states. */
       acpi_cpu_cx_cst(sc);
       acpi_cpu_cx_list(sc);
   
       /* Update the new lowest useable Cx state for all CPUs. */
       crit_enter();
       cpu_cx_count = 0;
       for (i = 0; i < cpu_ndevices; i++) {
           isc = device_get_softc(cpu_devices[i]);
           if (isc->cpu_cx_count > cpu_cx_count)
               cpu_cx_count = isc->cpu_cx_count;
       }
       crit_exit();
   }
   
   static int
   acpi_cpu_quirks(void)
   {
       device_t acpi_dev;
       uint32_t val;
   
       ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
   
       /*
        * Bus mastering arbitration control is needed to keep caches coherent
        * while sleeping in C3.  If it's not present but a working flush cache
        * instruction is present, flush the caches before entering C3 instead.
        * Otherwise, just disable C3 completely.
        */
       if (AcpiGbl_FADT.Pm2ControlBlock == 0 ||
           AcpiGbl_FADT.Pm2ControlLength == 0) {
           if ((AcpiGbl_FADT.Flags & ACPI_FADT_WBINVD) &&
               (AcpiGbl_FADT.Flags & ACPI_FADT_WBINVD_FLUSH) == 0) {
               cpu_quirks |= CPU_QUIRK_NO_BM_CTRL;
               ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                   "acpi_cpu: no BM control, using flush cache method\n"));
           } else {
               cpu_quirks |= CPU_QUIRK_NO_C3;
               ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                   "acpi_cpu: no BM control, C3 not available\n"));
           }
       }
   
       /*
        * If we are using generic Cx mode, C3 on multiple CPUs requires using
        * the expensive flush cache instruction.
        */
       if (cpu_cx_generic && ncpus > 1) {
           cpu_quirks |= CPU_QUIRK_NO_BM_CTRL;
           ACPI_DEBUG_PRINT((ACPI_DB_INFO,
               "acpi_cpu: SMP, using flush cache mode for C3\n"));
       }
   
       /* Look for various quirks of the PIIX4 part. */
       acpi_dev = pci_find_device(PCI_VENDOR_INTEL, PCI_DEVICE_82371AB_3);
       if (acpi_dev != NULL) {
           switch (pci_get_revid(acpi_dev)) {
           /*
            * Disable C3 support for all PIIX4 chipsets.  Some of these parts
            * do not report the BMIDE status to the BM status register and
            * others have a livelock bug if Type-F DMA is enabled.  Linux
            * works around the BMIDE bug by reading the BM status directly
            * but we take the simpler approach of disabling C3 for these
            * parts.
            *
            * See erratum #18 ("C3 Power State/BMIDE and Type-F DMA
            * Livelock") from the January 2002 PIIX4 specification update.
            * Applies to all PIIX4 models.
            *
            * Also, make sure that all interrupts cause a "Stop Break"
            * event to exit from C2 state.
            * Also, BRLD_EN_BM (ACPI_BITREG_BUS_MASTER_RLD in ACPI-speak)
            * should be set to zero, otherwise it causes C2 to short-sleep.
            * PIIX4 doesn't properly support C3 and bus master activity
            * need not break out of C2.
            */
           case PCI_REVISION_A_STEP:
           case PCI_REVISION_B_STEP:
           case PCI_REVISION_4E:
           case PCI_REVISION_4M:
               cpu_quirks |= CPU_QUIRK_NO_C3;
               ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                   "acpi_cpu: working around PIIX4 bug, disabling C3\n"));
   
               val = pci_read_config(acpi_dev, PIIX4_DEVACTB_REG, 4);
               if ((val & PIIX4_STOP_BREAK_MASK) != PIIX4_STOP_BREAK_MASK) {
                   ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                       "acpi_cpu: PIIX4: enabling IRQs to generate Stop Break\n"));
                   val |= PIIX4_STOP_BREAK_MASK;
                   pci_write_config(acpi_dev, PIIX4_DEVACTB_REG, val, 4);
               }
               AcpiReadBitRegister(ACPI_BITREG_BUS_MASTER_RLD, &val);
               if (val) {
                   ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                       "acpi_cpu: PIIX4: reset BRLD_EN_BM\n"));
                   AcpiWriteBitRegister(ACPI_BITREG_BUS_MASTER_RLD, 0);
               }
               break;
           default:
               break;
           }
       }
   
       return (0);
   }
   
   static int
   acpi_cpu_usage_sysctl(SYSCTL_HANDLER_ARGS)
   {
       struct acpi_cpu_softc *sc;
       struct sbuf  sb;
       char         buf[128];
       int          i;
       uintmax_t    fract, sum, whole;
   
       sc = (struct acpi_cpu_softc *) arg1;
       sum = 0;
       for (i = 0; i < sc->cpu_cx_count; i++)
           sum += sc->cpu_cx_stats[i];
       sbuf_new(&sb, buf, sizeof(buf), SBUF_FIXEDLEN);
       for (i = 0; i < sc->cpu_cx_count; i++) {
           if (sum > 0) {
               whole = (uintmax_t)sc->cpu_cx_stats[i] * 100;
               fract = (whole % sum) * 100;
               sbuf_printf(&sb, "%u.%02u%% ", (u_int)(whole / sum),
                   (u_int)(fract / sum));
           } else
               sbuf_printf(&sb, "0.00%% ");
       }
       sbuf_printf(&sb, "last %dus", sc->cpu_prev_sleep);
       sbuf_trim(&sb);
       sbuf_finish(&sb);
       sysctl_handle_string(oidp, sbuf_data(&sb), sbuf_len(&sb), req);
       sbuf_delete(&sb);
   
       return (0);
   }
   
   static int
   acpi_cpu_set_cx_lowest(struct acpi_cpu_softc *sc, int val)
   {
       int i, old_lowest, error = 0;
       uint32_t old_type, type;
   
       get_mplock();
   
       old_lowest = atomic_swap_int(&sc->cpu_cx_lowest, val);
  
      old_type = sc->cpu_cx_states[old_lowest].type;
      type = sc->cpu_cx_states[val].type;
      if (old_type == ACPI_STATE_C3 && type != ACPI_STATE_C3) {
          KKASSERT(cpu_c3_ncpus > 0);
          if (atomic_fetchadd_int(&cpu_c3_ncpus, -1) == 1) {
              /*
               * All of the CPUs exit C3 state, use a better
               * one shot timer.
               */
              error = cputimer_intr_select_caps(CPUTIMER_INTR_CAP_NONE);
              KKASSERT(!error);
              cputimer_intr_restart();
          }
      } else if (type == ACPI_STATE_C3 && old_type != ACPI_STATE_C3) {
          if (atomic_fetchadd_int(&cpu_c3_ncpus, 1) == 0) {
              /*
               * When the first CPU enters C3 state, switch
               * to an one shot timer, which could handle
               * C3 state, i.e. the timer will not hang.
               */
              error = cputimer_intr_select_caps(CPUTIMER_INTR_CAP_PS);
              if (!error) {
                  cputimer_intr_restart();
              } else {
                  kprintf("no suitable intr cputimer found\n");
  
                  /* Restore */
                  sc->cpu_cx_lowest = old_lowest;
                  atomic_fetchadd_int(&cpu_c3_ncpus, -1);
              }
          }
      }
  
      rel_mplock();
  
      if (error)
          return error;
  
      /* If not disabling, cache the new lowest non-C3 state. */
      sc->cpu_non_c3 = 0;
      for (i = sc->cpu_cx_lowest; i >= 0; i--) {
          if (sc->cpu_cx_states[i].type < ACPI_STATE_C3) {
              sc->cpu_non_c3 = i;
              break;
          }
      }
  
      /* Reset the statistics counters. */
      bzero(sc->cpu_cx_stats, sizeof(sc->cpu_cx_stats));
      return (0);
  }
  
  static int
  acpi_cpu_cx_lowest_sysctl(SYSCTL_HANDLER_ARGS)
  {
      struct       acpi_cpu_softc *sc;
      char         state[8];
      int          val, error;
  
      sc = (struct acpi_cpu_softc *) arg1;
      ksnprintf(state, sizeof(state), "C%d", sc->cpu_cx_lowest + 1);
      error = sysctl_handle_string(oidp, state, sizeof(state), req);
      if (error != 0 || req->newptr == NULL)
          return (error);
      if (strlen(state) < 2 || toupper(state[0]) != 'C')
          return (EINVAL);
      val = (int) strtol(state + 1, NULL, 10) - 1;
      if (val < 0 || val > sc->cpu_cx_count - 1)
          return (EINVAL);
  
      crit_enter();
      error = acpi_cpu_set_cx_lowest(sc, val);
      crit_exit();
  
      return error;
  }
  
  static int
  acpi_cpu_global_cx_lowest_sysctl(SYSCTL_HANDLER_ARGS)
  {
      struct      acpi_cpu_softc *sc;
      char        state[8];
      int         val, error, i;
  
      ksnprintf(state, sizeof(state), "C%d", cpu_cx_lowest + 1);
      error = sysctl_handle_string(oidp, state, sizeof(state), req);
      if (error != 0 || req->newptr == NULL)
          return (error);
      if (strlen(state) < 2 || toupper(state[0]) != 'C')
          return (EINVAL);
      val = (int) strtol(state + 1, NULL, 10) - 1;
      if (val < 0 || val > cpu_cx_count - 1)
          return (EINVAL);
      cpu_cx_lowest = val;
  
      /* Update the new lowest useable Cx state for all CPUs. */
      crit_enter();
      for (i = 0; i < cpu_ndevices; i++) {
          sc = device_get_softc(cpu_devices[i]);
          error = acpi_cpu_set_cx_lowest(sc, val);
          if (error) {
              KKASSERT(i == 0);
              break;
          }
      }
      crit_exit();
  
      return error;
  }
  
  /*
   * Put the CPU in C1 in a machine-dependant way.
   * XXX: shouldn't be here!
   */
  static void
  acpi_cpu_c1(void)
  {
  #ifdef __ia64__
      ia64_call_pal_static(PAL_HALT_LIGHT, 0, 0, 0);
  #else
      splz();
      if ((mycpu->gd_reqflags & RQF_IDLECHECK_WK_MASK) == 0)
          __asm __volatile("sti; hlt");
      else
          __asm __volatile("sti; pause");
  #endif /* !__ia64__ */
  }

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