qemu-e2k/hw/acpi/core.c
Markus Armbruster 0b8fa32f55 Include qemu/module.h where needed, drop it from qemu-common.h
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20190523143508.25387-4-armbru@redhat.com>
[Rebased with conflicts resolved automatically, except for
hw/usb/dev-hub.c hw/misc/exynos4210_rng.c hw/misc/bcm2835_rng.c
hw/misc/aspeed_scu.c hw/display/virtio-vga.c hw/arm/stm32f205_soc.c;
ui/cocoa.m fixed up]
2019-06-12 13:18:33 +02:00

730 lines
21 KiB
C

/*
* ACPI implementation
*
* Copyright (c) 2006 Fabrice Bellard
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License version 2 as published by the Free Software Foundation.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>
*
* Contributions after 2012-01-13 are licensed under the terms of the
* GNU GPL, version 2 or (at your option) any later version.
*/
#include "qemu/osdep.h"
#include "sysemu/sysemu.h"
#include "hw/hw.h"
#include "hw/acpi/acpi.h"
#include "hw/nvram/fw_cfg.h"
#include "qemu/config-file.h"
#include "qapi/error.h"
#include "qapi/opts-visitor.h"
#include "qapi/qapi-events-run-state.h"
#include "qapi/qapi-visit-misc.h"
#include "qemu/error-report.h"
#include "qemu/module.h"
#include "qemu/option.h"
struct acpi_table_header {
uint16_t _length; /* our length, not actual part of the hdr */
/* allows easier parsing for fw_cfg clients */
char sig[4]
QEMU_NONSTRING; /* ACPI signature (4 ASCII characters) */
uint32_t length; /* Length of table, in bytes, including header */
uint8_t revision; /* ACPI Specification minor version # */
uint8_t checksum; /* To make sum of entire table == 0 */
char oem_id[6]
QEMU_NONSTRING; /* OEM identification */
char oem_table_id[8]
QEMU_NONSTRING; /* OEM table identification */
uint32_t oem_revision; /* OEM revision number */
char asl_compiler_id[4]
QEMU_NONSTRING; /* ASL compiler vendor ID */
uint32_t asl_compiler_revision; /* ASL compiler revision number */
} QEMU_PACKED;
#define ACPI_TABLE_HDR_SIZE sizeof(struct acpi_table_header)
#define ACPI_TABLE_PFX_SIZE sizeof(uint16_t) /* size of the extra prefix */
static const char unsigned dfl_hdr[ACPI_TABLE_HDR_SIZE - ACPI_TABLE_PFX_SIZE] =
"QEMU\0\0\0\0\1\0" /* sig (4), len(4), revno (1), csum (1) */
"QEMUQEQEMUQEMU\1\0\0\0" /* OEM id (6), table (8), revno (4) */
"QEMU\1\0\0\0" /* ASL compiler ID (4), version (4) */
;
char unsigned *acpi_tables;
size_t acpi_tables_len;
static QemuOptsList qemu_acpi_opts = {
.name = "acpi",
.implied_opt_name = "data",
.head = QTAILQ_HEAD_INITIALIZER(qemu_acpi_opts.head),
.desc = { { 0 } } /* validated with OptsVisitor */
};
static void acpi_register_config(void)
{
qemu_add_opts(&qemu_acpi_opts);
}
opts_init(acpi_register_config);
static int acpi_checksum(const uint8_t *data, int len)
{
int sum, i;
sum = 0;
for (i = 0; i < len; i++) {
sum += data[i];
}
return (-sum) & 0xff;
}
/* Install a copy of the ACPI table specified in @blob.
*
* If @has_header is set, @blob starts with the System Description Table Header
* structure. Otherwise, "dfl_hdr" is prepended. In any case, each header field
* is optionally overwritten from @hdrs.
*
* It is valid to call this function with
* (@blob == NULL && bloblen == 0 && !has_header).
*
* @hdrs->file and @hdrs->data are ignored.
*
* SIZE_MAX is considered "infinity" in this function.
*
* The number of tables that can be installed is not limited, but the 16-bit
* counter at the beginning of "acpi_tables" wraps around after UINT16_MAX.
*/
static void acpi_table_install(const char unsigned *blob, size_t bloblen,
bool has_header,
const struct AcpiTableOptions *hdrs,
Error **errp)
{
size_t body_start;
const char unsigned *hdr_src;
size_t body_size, acpi_payload_size;
struct acpi_table_header *ext_hdr;
unsigned changed_fields;
/* Calculate where the ACPI table body starts within the blob, plus where
* to copy the ACPI table header from.
*/
if (has_header) {
/* _length | ACPI header in blob | blob body
* ^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^
* ACPI_TABLE_PFX_SIZE sizeof dfl_hdr body_size
* == body_start
*
* ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
* acpi_payload_size == bloblen
*/
body_start = sizeof dfl_hdr;
if (bloblen < body_start) {
error_setg(errp, "ACPI table claiming to have header is too "
"short, available: %zu, expected: %zu", bloblen,
body_start);
return;
}
hdr_src = blob;
} else {
/* _length | ACPI header in template | blob body
* ^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^
* ACPI_TABLE_PFX_SIZE sizeof dfl_hdr body_size
* == bloblen
*
* ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
* acpi_payload_size
*/
body_start = 0;
hdr_src = dfl_hdr;
}
body_size = bloblen - body_start;
acpi_payload_size = sizeof dfl_hdr + body_size;
if (acpi_payload_size > UINT16_MAX) {
error_setg(errp, "ACPI table too big, requested: %zu, max: %u",
acpi_payload_size, (unsigned)UINT16_MAX);
return;
}
/* We won't fail from here on. Initialize / extend the globals. */
if (acpi_tables == NULL) {
acpi_tables_len = sizeof(uint16_t);
acpi_tables = g_malloc0(acpi_tables_len);
}
acpi_tables = g_realloc(acpi_tables, acpi_tables_len +
ACPI_TABLE_PFX_SIZE +
sizeof dfl_hdr + body_size);
ext_hdr = (struct acpi_table_header *)(acpi_tables + acpi_tables_len);
acpi_tables_len += ACPI_TABLE_PFX_SIZE;
memcpy(acpi_tables + acpi_tables_len, hdr_src, sizeof dfl_hdr);
acpi_tables_len += sizeof dfl_hdr;
if (blob != NULL) {
memcpy(acpi_tables + acpi_tables_len, blob + body_start, body_size);
acpi_tables_len += body_size;
}
/* increase number of tables */
stw_le_p(acpi_tables, lduw_le_p(acpi_tables) + 1u);
/* Update the header fields. The strings need not be NUL-terminated. */
changed_fields = 0;
ext_hdr->_length = cpu_to_le16(acpi_payload_size);
if (hdrs->has_sig) {
strncpy(ext_hdr->sig, hdrs->sig, sizeof ext_hdr->sig);
++changed_fields;
}
if (has_header && le32_to_cpu(ext_hdr->length) != acpi_payload_size) {
warn_report("ACPI table has wrong length, header says "
"%" PRIu32 ", actual size %zu bytes",
le32_to_cpu(ext_hdr->length), acpi_payload_size);
}
ext_hdr->length = cpu_to_le32(acpi_payload_size);
if (hdrs->has_rev) {
ext_hdr->revision = hdrs->rev;
++changed_fields;
}
ext_hdr->checksum = 0;
if (hdrs->has_oem_id) {
strncpy(ext_hdr->oem_id, hdrs->oem_id, sizeof ext_hdr->oem_id);
++changed_fields;
}
if (hdrs->has_oem_table_id) {
strncpy(ext_hdr->oem_table_id, hdrs->oem_table_id,
sizeof ext_hdr->oem_table_id);
++changed_fields;
}
if (hdrs->has_oem_rev) {
ext_hdr->oem_revision = cpu_to_le32(hdrs->oem_rev);
++changed_fields;
}
if (hdrs->has_asl_compiler_id) {
strncpy(ext_hdr->asl_compiler_id, hdrs->asl_compiler_id,
sizeof ext_hdr->asl_compiler_id);
++changed_fields;
}
if (hdrs->has_asl_compiler_rev) {
ext_hdr->asl_compiler_revision = cpu_to_le32(hdrs->asl_compiler_rev);
++changed_fields;
}
if (!has_header && changed_fields == 0) {
warn_report("ACPI table: no headers are specified");
}
/* recalculate checksum */
ext_hdr->checksum = acpi_checksum((const char unsigned *)ext_hdr +
ACPI_TABLE_PFX_SIZE, acpi_payload_size);
}
void acpi_table_add(const QemuOpts *opts, Error **errp)
{
AcpiTableOptions *hdrs = NULL;
Error *err = NULL;
char **pathnames = NULL;
char **cur;
size_t bloblen = 0;
char unsigned *blob = NULL;
{
Visitor *v;
v = opts_visitor_new(opts);
visit_type_AcpiTableOptions(v, NULL, &hdrs, &err);
visit_free(v);
}
if (err) {
goto out;
}
if (hdrs->has_file == hdrs->has_data) {
error_setg(&err, "'-acpitable' requires one of 'data' or 'file'");
goto out;
}
pathnames = g_strsplit(hdrs->has_file ? hdrs->file : hdrs->data, ":", 0);
if (pathnames == NULL || pathnames[0] == NULL) {
error_setg(&err, "'-acpitable' requires at least one pathname");
goto out;
}
/* now read in the data files, reallocating buffer as needed */
for (cur = pathnames; *cur; ++cur) {
int fd = open(*cur, O_RDONLY | O_BINARY);
if (fd < 0) {
error_setg(&err, "can't open file %s: %s", *cur, strerror(errno));
goto out;
}
for (;;) {
char unsigned data[8192];
ssize_t r;
r = read(fd, data, sizeof data);
if (r == 0) {
break;
} else if (r > 0) {
blob = g_realloc(blob, bloblen + r);
memcpy(blob + bloblen, data, r);
bloblen += r;
} else if (errno != EINTR) {
error_setg(&err, "can't read file %s: %s",
*cur, strerror(errno));
close(fd);
goto out;
}
}
close(fd);
}
acpi_table_install(blob, bloblen, hdrs->has_file, hdrs, &err);
out:
g_free(blob);
g_strfreev(pathnames);
qapi_free_AcpiTableOptions(hdrs);
error_propagate(errp, err);
}
unsigned acpi_table_len(void *current)
{
struct acpi_table_header *hdr = current - sizeof(hdr->_length);
return hdr->_length;
}
static
void *acpi_table_hdr(void *h)
{
struct acpi_table_header *hdr = h;
return &hdr->sig;
}
uint8_t *acpi_table_first(void)
{
if (!acpi_tables) {
return NULL;
}
return acpi_table_hdr(acpi_tables + ACPI_TABLE_PFX_SIZE);
}
uint8_t *acpi_table_next(uint8_t *current)
{
uint8_t *next = current + acpi_table_len(current);
if (next - acpi_tables >= acpi_tables_len) {
return NULL;
} else {
return acpi_table_hdr(next);
}
}
int acpi_get_slic_oem(AcpiSlicOem *oem)
{
uint8_t *u;
for (u = acpi_table_first(); u; u = acpi_table_next(u)) {
struct acpi_table_header *hdr = (void *)(u - sizeof(hdr->_length));
if (memcmp(hdr->sig, "SLIC", 4) == 0) {
oem->id = hdr->oem_id;
oem->table_id = hdr->oem_table_id;
return 0;
}
}
return -1;
}
static void acpi_notify_wakeup(Notifier *notifier, void *data)
{
ACPIREGS *ar = container_of(notifier, ACPIREGS, wakeup);
WakeupReason *reason = data;
switch (*reason) {
case QEMU_WAKEUP_REASON_RTC:
ar->pm1.evt.sts |=
(ACPI_BITMASK_WAKE_STATUS | ACPI_BITMASK_RT_CLOCK_STATUS);
break;
case QEMU_WAKEUP_REASON_PMTIMER:
ar->pm1.evt.sts |=
(ACPI_BITMASK_WAKE_STATUS | ACPI_BITMASK_TIMER_STATUS);
break;
case QEMU_WAKEUP_REASON_OTHER:
/* ACPI_BITMASK_WAKE_STATUS should be set on resume.
Pretend that resume was caused by power button */
ar->pm1.evt.sts |=
(ACPI_BITMASK_WAKE_STATUS | ACPI_BITMASK_POWER_BUTTON_STATUS);
break;
default:
break;
}
}
/* ACPI PM1a EVT */
uint16_t acpi_pm1_evt_get_sts(ACPIREGS *ar)
{
/* Compare ns-clock, not PM timer ticks, because
acpi_pm_tmr_update function uses ns for setting the timer. */
int64_t d = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
if (d >= muldiv64(ar->tmr.overflow_time,
NANOSECONDS_PER_SECOND, PM_TIMER_FREQUENCY)) {
ar->pm1.evt.sts |= ACPI_BITMASK_TIMER_STATUS;
}
return ar->pm1.evt.sts;
}
static void acpi_pm1_evt_write_sts(ACPIREGS *ar, uint16_t val)
{
uint16_t pm1_sts = acpi_pm1_evt_get_sts(ar);
if (pm1_sts & val & ACPI_BITMASK_TIMER_STATUS) {
/* if TMRSTS is reset, then compute the new overflow time */
acpi_pm_tmr_calc_overflow_time(ar);
}
ar->pm1.evt.sts &= ~val;
}
static void acpi_pm1_evt_write_en(ACPIREGS *ar, uint16_t val)
{
ar->pm1.evt.en = val;
qemu_system_wakeup_enable(QEMU_WAKEUP_REASON_RTC,
val & ACPI_BITMASK_RT_CLOCK_ENABLE);
qemu_system_wakeup_enable(QEMU_WAKEUP_REASON_PMTIMER,
val & ACPI_BITMASK_TIMER_ENABLE);
}
void acpi_pm1_evt_power_down(ACPIREGS *ar)
{
if (ar->pm1.evt.en & ACPI_BITMASK_POWER_BUTTON_ENABLE) {
ar->pm1.evt.sts |= ACPI_BITMASK_POWER_BUTTON_STATUS;
ar->tmr.update_sci(ar);
}
}
void acpi_pm1_evt_reset(ACPIREGS *ar)
{
ar->pm1.evt.sts = 0;
ar->pm1.evt.en = 0;
qemu_system_wakeup_enable(QEMU_WAKEUP_REASON_RTC, 0);
qemu_system_wakeup_enable(QEMU_WAKEUP_REASON_PMTIMER, 0);
}
static uint64_t acpi_pm_evt_read(void *opaque, hwaddr addr, unsigned width)
{
ACPIREGS *ar = opaque;
switch (addr) {
case 0:
return acpi_pm1_evt_get_sts(ar);
case 2:
return ar->pm1.evt.en;
default:
return 0;
}
}
static void acpi_pm_evt_write(void *opaque, hwaddr addr, uint64_t val,
unsigned width)
{
ACPIREGS *ar = opaque;
switch (addr) {
case 0:
acpi_pm1_evt_write_sts(ar, val);
ar->pm1.evt.update_sci(ar);
break;
case 2:
acpi_pm1_evt_write_en(ar, val);
ar->pm1.evt.update_sci(ar);
break;
}
}
static const MemoryRegionOps acpi_pm_evt_ops = {
.read = acpi_pm_evt_read,
.write = acpi_pm_evt_write,
.valid.min_access_size = 2,
.valid.max_access_size = 2,
.endianness = DEVICE_LITTLE_ENDIAN,
};
void acpi_pm1_evt_init(ACPIREGS *ar, acpi_update_sci_fn update_sci,
MemoryRegion *parent)
{
ar->pm1.evt.update_sci = update_sci;
memory_region_init_io(&ar->pm1.evt.io, memory_region_owner(parent),
&acpi_pm_evt_ops, ar, "acpi-evt", 4);
memory_region_add_subregion(parent, 0, &ar->pm1.evt.io);
}
/* ACPI PM_TMR */
void acpi_pm_tmr_update(ACPIREGS *ar, bool enable)
{
int64_t expire_time;
/* schedule a timer interruption if needed */
if (enable) {
expire_time = muldiv64(ar->tmr.overflow_time, NANOSECONDS_PER_SECOND,
PM_TIMER_FREQUENCY);
timer_mod(ar->tmr.timer, expire_time);
} else {
timer_del(ar->tmr.timer);
}
}
static inline int64_t acpi_pm_tmr_get_clock(void)
{
return muldiv64(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL), PM_TIMER_FREQUENCY,
NANOSECONDS_PER_SECOND);
}
void acpi_pm_tmr_calc_overflow_time(ACPIREGS *ar)
{
int64_t d = acpi_pm_tmr_get_clock();
ar->tmr.overflow_time = (d + 0x800000LL) & ~0x7fffffLL;
}
static uint32_t acpi_pm_tmr_get(ACPIREGS *ar)
{
uint32_t d = acpi_pm_tmr_get_clock();
return d & 0xffffff;
}
static void acpi_pm_tmr_timer(void *opaque)
{
ACPIREGS *ar = opaque;
qemu_system_wakeup_request(QEMU_WAKEUP_REASON_PMTIMER, NULL);
ar->tmr.update_sci(ar);
}
static uint64_t acpi_pm_tmr_read(void *opaque, hwaddr addr, unsigned width)
{
return acpi_pm_tmr_get(opaque);
}
static void acpi_pm_tmr_write(void *opaque, hwaddr addr, uint64_t val,
unsigned width)
{
/* nothing */
}
static const MemoryRegionOps acpi_pm_tmr_ops = {
.read = acpi_pm_tmr_read,
.write = acpi_pm_tmr_write,
.valid.min_access_size = 4,
.valid.max_access_size = 4,
.endianness = DEVICE_LITTLE_ENDIAN,
};
void acpi_pm_tmr_init(ACPIREGS *ar, acpi_update_sci_fn update_sci,
MemoryRegion *parent)
{
ar->tmr.update_sci = update_sci;
ar->tmr.timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, acpi_pm_tmr_timer, ar);
memory_region_init_io(&ar->tmr.io, memory_region_owner(parent),
&acpi_pm_tmr_ops, ar, "acpi-tmr", 4);
memory_region_add_subregion(parent, 8, &ar->tmr.io);
}
void acpi_pm_tmr_reset(ACPIREGS *ar)
{
ar->tmr.overflow_time = 0;
timer_del(ar->tmr.timer);
}
/* ACPI PM1aCNT */
static void acpi_pm1_cnt_write(ACPIREGS *ar, uint16_t val)
{
ar->pm1.cnt.cnt = val & ~(ACPI_BITMASK_SLEEP_ENABLE);
if (val & ACPI_BITMASK_SLEEP_ENABLE) {
/* change suspend type */
uint16_t sus_typ = (val >> 10) & 7;
switch(sus_typ) {
case 0: /* soft power off */
qemu_system_shutdown_request(SHUTDOWN_CAUSE_GUEST_SHUTDOWN);
break;
case 1:
qemu_system_suspend_request();
break;
default:
if (sus_typ == ar->pm1.cnt.s4_val) { /* S4 request */
qapi_event_send_suspend_disk();
qemu_system_shutdown_request(SHUTDOWN_CAUSE_GUEST_SHUTDOWN);
}
break;
}
}
}
void acpi_pm1_cnt_update(ACPIREGS *ar,
bool sci_enable, bool sci_disable)
{
/* ACPI specs 3.0, 4.7.2.5 */
if (sci_enable) {
ar->pm1.cnt.cnt |= ACPI_BITMASK_SCI_ENABLE;
} else if (sci_disable) {
ar->pm1.cnt.cnt &= ~ACPI_BITMASK_SCI_ENABLE;
}
}
static uint64_t acpi_pm_cnt_read(void *opaque, hwaddr addr, unsigned width)
{
ACPIREGS *ar = opaque;
return ar->pm1.cnt.cnt;
}
static void acpi_pm_cnt_write(void *opaque, hwaddr addr, uint64_t val,
unsigned width)
{
acpi_pm1_cnt_write(opaque, val);
}
static const MemoryRegionOps acpi_pm_cnt_ops = {
.read = acpi_pm_cnt_read,
.write = acpi_pm_cnt_write,
.valid.min_access_size = 2,
.valid.max_access_size = 2,
.endianness = DEVICE_LITTLE_ENDIAN,
};
void acpi_pm1_cnt_init(ACPIREGS *ar, MemoryRegion *parent,
bool disable_s3, bool disable_s4, uint8_t s4_val)
{
FWCfgState *fw_cfg;
ar->pm1.cnt.s4_val = s4_val;
ar->wakeup.notify = acpi_notify_wakeup;
qemu_register_wakeup_notifier(&ar->wakeup);
/*
* Register wake-up support in QMP query-current-machine API
*/
qemu_register_wakeup_support();
memory_region_init_io(&ar->pm1.cnt.io, memory_region_owner(parent),
&acpi_pm_cnt_ops, ar, "acpi-cnt", 2);
memory_region_add_subregion(parent, 4, &ar->pm1.cnt.io);
fw_cfg = fw_cfg_find();
if (fw_cfg) {
uint8_t suspend[6] = {128, 0, 0, 129, 128, 128};
suspend[3] = 1 | ((!disable_s3) << 7);
suspend[4] = s4_val | ((!disable_s4) << 7);
fw_cfg_add_file(fw_cfg, "etc/system-states", g_memdup(suspend, 6), 6);
}
}
void acpi_pm1_cnt_reset(ACPIREGS *ar)
{
ar->pm1.cnt.cnt = 0;
}
/* ACPI GPE */
void acpi_gpe_init(ACPIREGS *ar, uint8_t len)
{
ar->gpe.len = len;
/* Only first len / 2 bytes are ever used,
* but the caller in ich9.c migrates full len bytes.
* TODO: fix ich9.c and drop the extra allocation.
*/
ar->gpe.sts = g_malloc0(len);
ar->gpe.en = g_malloc0(len);
}
void acpi_gpe_reset(ACPIREGS *ar)
{
memset(ar->gpe.sts, 0, ar->gpe.len / 2);
memset(ar->gpe.en, 0, ar->gpe.len / 2);
}
static uint8_t *acpi_gpe_ioport_get_ptr(ACPIREGS *ar, uint32_t addr)
{
uint8_t *cur = NULL;
if (addr < ar->gpe.len / 2) {
cur = ar->gpe.sts + addr;
} else if (addr < ar->gpe.len) {
cur = ar->gpe.en + addr - ar->gpe.len / 2;
} else {
abort();
}
return cur;
}
void acpi_gpe_ioport_writeb(ACPIREGS *ar, uint32_t addr, uint32_t val)
{
uint8_t *cur;
cur = acpi_gpe_ioport_get_ptr(ar, addr);
if (addr < ar->gpe.len / 2) {
/* GPE_STS */
*cur = (*cur) & ~val;
} else if (addr < ar->gpe.len) {
/* GPE_EN */
*cur = val;
} else {
abort();
}
}
uint32_t acpi_gpe_ioport_readb(ACPIREGS *ar, uint32_t addr)
{
uint8_t *cur;
uint32_t val;
cur = acpi_gpe_ioport_get_ptr(ar, addr);
val = 0;
if (cur != NULL) {
val = *cur;
}
return val;
}
void acpi_send_gpe_event(ACPIREGS *ar, qemu_irq irq,
AcpiEventStatusBits status)
{
ar->gpe.sts[0] |= status;
acpi_update_sci(ar, irq);
}
void acpi_update_sci(ACPIREGS *regs, qemu_irq irq)
{
int sci_level, pm1a_sts;
pm1a_sts = acpi_pm1_evt_get_sts(regs);
sci_level = ((pm1a_sts &
regs->pm1.evt.en & ACPI_BITMASK_PM1_COMMON_ENABLED) != 0) ||
((regs->gpe.sts[0] & regs->gpe.en[0]) != 0);
qemu_set_irq(irq, sci_level);
/* schedule a timer interruption if needed */
acpi_pm_tmr_update(regs,
(regs->pm1.evt.en & ACPI_BITMASK_TIMER_ENABLE) &&
!(pm1a_sts & ACPI_BITMASK_TIMER_STATUS));
}