* [PATCH 3/8] cpuidle: make cpuidle_curr_driver static
2010-05-28 6:01 ` [PATCH 1/8] cpuidle: fail to register if !CONFIG_CPU_IDLE Len Brown
2010-05-28 6:01 ` [PATCH 2/8] cpuidle: add cpuidle_unregister_driver() error check Len Brown
@ 2010-05-28 6:01 ` Len Brown
2010-05-28 6:01 ` [PATCH 4/8] ACPI: allow a native cpuidle driver to displace ACPI Len Brown
` (4 subsequent siblings)
6 siblings, 0 replies; 12+ messages in thread
From: Len Brown @ 2010-05-28 6:01 UTC (permalink / raw)
To: linux-pm; +Cc: linux-kernel, Len Brown
From: Len Brown <len.brown@intel.com>
cpuidle_register_driver() sets cpuidle_curr_driver
cpuidle_unregister_driver() clears cpuidle_curr_driver
We should't expose cpuidle_curr_driver to
potential modification except via these interfaces.
So make it static and create cpuidle_get_driver() to observe it.
Signed-off-by: Len Brown <len.brown@intel.com>
---
drivers/cpuidle/cpuidle.c | 12 +++++++-----
drivers/cpuidle/cpuidle.h | 1 -
drivers/cpuidle/driver.c | 11 ++++++++++-
drivers/cpuidle/sysfs.c | 5 +++--
include/linux/cpuidle.h | 2 ++
5 files changed, 22 insertions(+), 9 deletions(-)
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 12fdd39..1994885 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -156,7 +156,7 @@ int cpuidle_enable_device(struct cpuidle_device *dev)
if (dev->enabled)
return 0;
- if (!cpuidle_curr_driver || !cpuidle_curr_governor)
+ if (!cpuidle_get_driver() || !cpuidle_curr_governor)
return -EIO;
if (!dev->state_count)
return -EINVAL;
@@ -207,7 +207,7 @@ void cpuidle_disable_device(struct cpuidle_device *dev)
{
if (!dev->enabled)
return;
- if (!cpuidle_curr_driver || !cpuidle_curr_governor)
+ if (!cpuidle_get_driver() || !cpuidle_curr_governor)
return;
dev->enabled = 0;
@@ -271,10 +271,11 @@ static int __cpuidle_register_device(struct cpuidle_device *dev)
{
int ret;
struct sys_device *sys_dev = get_cpu_sysdev((unsigned long)dev->cpu);
+ struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver();
if (!sys_dev)
return -EINVAL;
- if (!try_module_get(cpuidle_curr_driver->owner))
+ if (!try_module_get(cpuidle_driver->owner))
return -EINVAL;
init_completion(&dev->kobj_unregister);
@@ -284,7 +285,7 @@ static int __cpuidle_register_device(struct cpuidle_device *dev)
per_cpu(cpuidle_devices, dev->cpu) = dev;
list_add(&dev->device_list, &cpuidle_detected_devices);
if ((ret = cpuidle_add_sysfs(sys_dev))) {
- module_put(cpuidle_curr_driver->owner);
+ module_put(cpuidle_driver->owner);
return ret;
}
@@ -325,6 +326,7 @@ EXPORT_SYMBOL_GPL(cpuidle_register_device);
void cpuidle_unregister_device(struct cpuidle_device *dev)
{
struct sys_device *sys_dev = get_cpu_sysdev((unsigned long)dev->cpu);
+ struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver();
if (dev->registered == 0)
return;
@@ -340,7 +342,7 @@ void cpuidle_unregister_device(struct cpuidle_device *dev)
cpuidle_resume_and_unlock();
- module_put(cpuidle_curr_driver->owner);
+ module_put(cpuidle_driver->owner);
}
EXPORT_SYMBOL_GPL(cpuidle_unregister_device);
diff --git a/drivers/cpuidle/cpuidle.h b/drivers/cpuidle/cpuidle.h
index 9476ba3..33e50d5 100644
--- a/drivers/cpuidle/cpuidle.h
+++ b/drivers/cpuidle/cpuidle.h
@@ -9,7 +9,6 @@
/* For internal use only */
extern struct cpuidle_governor *cpuidle_curr_governor;
-extern struct cpuidle_driver *cpuidle_curr_driver;
extern struct list_head cpuidle_governors;
extern struct list_head cpuidle_detected_devices;
extern struct mutex cpuidle_lock;
diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c
index 826b5c0..fd1601e 100644
--- a/drivers/cpuidle/driver.c
+++ b/drivers/cpuidle/driver.c
@@ -14,7 +14,7 @@
#include "cpuidle.h"
-struct cpuidle_driver *cpuidle_curr_driver;
+static struct cpuidle_driver *cpuidle_curr_driver;
DEFINE_SPINLOCK(cpuidle_driver_lock);
/**
@@ -40,6 +40,15 @@ int cpuidle_register_driver(struct cpuidle_driver *drv)
EXPORT_SYMBOL_GPL(cpuidle_register_driver);
/**
+ * cpuidle_get_driver - return the current driver
+ */
+struct cpuidle_driver *cpuidle_get_driver(void)
+{
+ return cpuidle_curr_driver;
+}
+EXPORT_SYMBOL_GPL(cpuidle_get_driver);
+
+/**
* cpuidle_unregister_driver - unregisters a driver
* @drv: the driver
*/
diff --git a/drivers/cpuidle/sysfs.c b/drivers/cpuidle/sysfs.c
index 0ba9c8b..0310ffa 100644
--- a/drivers/cpuidle/sysfs.c
+++ b/drivers/cpuidle/sysfs.c
@@ -47,10 +47,11 @@ static ssize_t show_current_driver(struct sysdev_class *class,
char *buf)
{
ssize_t ret;
+ struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver();
spin_lock(&cpuidle_driver_lock);
- if (cpuidle_curr_driver)
- ret = sprintf(buf, "%s\n", cpuidle_curr_driver->name);
+ if (cpuidle_driver)
+ ret = sprintf(buf, "%s\n", cpuidle_driver->name);
else
ret = sprintf(buf, "none\n");
spin_unlock(&cpuidle_driver_lock);
diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
index f5e6480..55215cc 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -125,6 +125,7 @@ struct cpuidle_driver {
#ifdef CONFIG_CPU_IDLE
extern int cpuidle_register_driver(struct cpuidle_driver *drv);
+struct cpuidle_driver *cpuidle_get_driver(void);
extern void cpuidle_unregister_driver(struct cpuidle_driver *drv);
extern int cpuidle_register_device(struct cpuidle_device *dev);
extern void cpuidle_unregister_device(struct cpuidle_device *dev);
@@ -138,6 +139,7 @@ extern void cpuidle_disable_device(struct cpuidle_device *dev);
static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
{return -ENODEV; }
+static inline struct cpuidle_driver *cpuidle_get_driver(void) {return NULL; }
static inline void cpuidle_unregister_driver(struct cpuidle_driver *drv) { }
static inline int cpuidle_register_device(struct cpuidle_device *dev)
{return -ENODEV; }
--
1.6.0.6
^ permalink raw reply related [flat|nested] 12+ messages in thread* [PATCH 7/8] ACPI: acpi_idle: touch TS_POLLING only in the non-MWAIT case
2010-05-28 6:01 ` [PATCH 1/8] cpuidle: fail to register if !CONFIG_CPU_IDLE Len Brown
` (4 preceding siblings ...)
2010-05-28 6:01 ` [PATCH 6/8] acpi_pad: uses MONITOR/MWAIT, so it doesn't need to clear TS_POLLING Len Brown
@ 2010-05-28 6:02 ` Len Brown
2010-05-28 16:19 ` Venkatesh Pallipadi
2010-05-28 6:02 ` [PATCH 8/8] intel_idle: native hardware cpuidle driver for latest Intel processors Len Brown
6 siblings, 1 reply; 12+ messages in thread
From: Len Brown @ 2010-05-28 6:02 UTC (permalink / raw)
To: linux-pm; +Cc: linux-kernel, Len Brown, Venkatesh Pallipadi
From: Len Brown <len.brown@intel.com>
commit d306ebc28649b89877a22158fe0076f06cc46f60
(ACPI: Be in TS_POLLING state during mwait based C-state entry)
fixed an important power & performance issue where ACPI c2 and c3 C-states
were clearing TS_POLLING even when using MWAIT (ACPI_STATE_FFH).
That bug had been causing us to receive redundant scheduling interrups
when we had already been woken up by MONITOR/MWAIT.
Following up on that...
In the MWAIT case, we don't have to subsequently
check need_resched(), as that c heck was there
for the TS_POLLING-clearing case.
Note that not only does the cpuidle calling function
already check need_resched() before calling us, the
low-level entry into monitor/mwait calls it twice --
guaranteeing that a write to the trigger address
can not go un-noticed.
Also, in this case, we don't have to set TS_POLLING
when we wake, because we never cleared it.
Signed-off-by: Len Brown <len.brown@intel.com>
Cc: Venkatesh Pallipadi <venki@google.com>
---
drivers/acpi/processor_idle.c | 28 ++++++++++++++++------------
1 files changed, 16 insertions(+), 12 deletions(-)
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 5939e7f..a4166e2 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -881,6 +881,7 @@ static int acpi_idle_enter_simple(struct cpuidle_device *dev,
return(acpi_idle_enter_c1(dev, state));
local_irq_disable();
+
if (cx->entry_method != ACPI_CSTATE_FFH) {
current_thread_info()->status &= ~TS_POLLING;
/*
@@ -888,12 +889,12 @@ static int acpi_idle_enter_simple(struct cpuidle_device *dev,
* NEED_RESCHED:
*/
smp_mb();
- }
- if (unlikely(need_resched())) {
- current_thread_info()->status |= TS_POLLING;
- local_irq_enable();
- return 0;
+ if (unlikely(need_resched())) {
+ current_thread_info()->status |= TS_POLLING;
+ local_irq_enable();
+ return 0;
+ }
}
/*
@@ -918,7 +919,8 @@ static int acpi_idle_enter_simple(struct cpuidle_device *dev,
sched_clock_idle_wakeup_event(sleep_ticks*PM_TIMER_TICK_NS);
local_irq_enable();
- current_thread_info()->status |= TS_POLLING;
+ if (cx->entry_method != ACPI_CSTATE_FFH)
+ current_thread_info()->status |= TS_POLLING;
cx->usage++;
@@ -968,6 +970,7 @@ static int acpi_idle_enter_bm(struct cpuidle_device *dev,
}
local_irq_disable();
+
if (cx->entry_method != ACPI_CSTATE_FFH) {
current_thread_info()->status &= ~TS_POLLING;
/*
@@ -975,12 +978,12 @@ static int acpi_idle_enter_bm(struct cpuidle_device *dev,
* NEED_RESCHED:
*/
smp_mb();
- }
- if (unlikely(need_resched())) {
- current_thread_info()->status |= TS_POLLING;
- local_irq_enable();
- return 0;
+ if (unlikely(need_resched())) {
+ current_thread_info()->status |= TS_POLLING;
+ local_irq_enable();
+ return 0;
+ }
}
acpi_unlazy_tlb(smp_processor_id());
@@ -1032,7 +1035,8 @@ static int acpi_idle_enter_bm(struct cpuidle_device *dev,
sched_clock_idle_wakeup_event(sleep_ticks*PM_TIMER_TICK_NS);
local_irq_enable();
- current_thread_info()->status |= TS_POLLING;
+ if (cx->entry_method != ACPI_CSTATE_FFH)
+ current_thread_info()->status |= TS_POLLING;
cx->usage++;
--
1.6.0.6
^ permalink raw reply related [flat|nested] 12+ messages in thread* [PATCH 8/8] intel_idle: native hardware cpuidle driver for latest Intel processors
2010-05-28 6:01 ` [PATCH 1/8] cpuidle: fail to register if !CONFIG_CPU_IDLE Len Brown
` (5 preceding siblings ...)
2010-05-28 6:02 ` [PATCH 7/8] ACPI: acpi_idle: touch TS_POLLING only in the non-MWAIT case Len Brown
@ 2010-05-28 6:02 ` Len Brown
6 siblings, 0 replies; 12+ messages in thread
From: Len Brown @ 2010-05-28 6:02 UTC (permalink / raw)
To: linux-pm; +Cc: linux-kernel, Len Brown
From: Len Brown <len.brown@intel.com>
This EXPERIMENTAL driver supersedes acpi_idle on
Intel Atom Processors, Intel Core i3/i5/i7 Processors
and associated Intel Xeon processors.
It does not support the Intel Core2 processor or earlier.
For kernels configured with ACPI, CONFIG_INTEL_IDLE=y
allows intel_idle to probe before the ACPI processor driver.
In this case, note that you can boot with "intel_idle.max_cstate=0"
to disable intel_idle and to fall back on ACPI's "acpi_idle".
Typical Linux distributions load ACPI processor module early,
making CONFIG_INTEL_IDLE=m not useful on ACPI platforms.
intel_idle probes all processors at module_init time.
Processors that are hot-added later will be limited
to using C1 in idle.
Signed-off-by: Len Brown <len.brown@intel.com>
---
MAINTAINERS | 7 +
drivers/Makefile | 2 +-
drivers/acpi/processor_driver.c | 6 +-
drivers/idle/Kconfig | 11 +
drivers/idle/Makefile | 1 +
drivers/idle/intel_idle.c | 461 +++++++++++++++++++++++++++++++++++++++
6 files changed, 486 insertions(+), 2 deletions(-)
create mode 100755 drivers/idle/intel_idle.c
diff --git a/MAINTAINERS b/MAINTAINERS
index d329b05..276e79b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2850,6 +2850,13 @@ T: git git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input.git
S: Maintained
F: drivers/input/
+INTEL IDLE DRIVER
+M: Len Brown <lenb@kernel.org>
+L: linux-pm@lists.linux-foundation.org
+T: git git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-idle-2.6.git
+S: Supported
+F: drivers/idle/intel_idle.c
+
INTEL FRAMEBUFFER DRIVER (excluding 810 and 815)
M: Maik Broemme <mbroemme@plusserver.de>
L: linux-fbdev@vger.kernel.org
diff --git a/drivers/Makefile b/drivers/Makefile
index f42a030..91874e0 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -10,6 +10,7 @@ obj-$(CONFIG_PCI) += pci/
obj-$(CONFIG_PARISC) += parisc/
obj-$(CONFIG_RAPIDIO) += rapidio/
obj-y += video/
+obj-y += idle/
obj-$(CONFIG_ACPI) += acpi/
obj-$(CONFIG_SFI) += sfi/
# PnP must come after ACPI since it will eventually need to check if acpi
@@ -91,7 +92,6 @@ obj-$(CONFIG_EISA) += eisa/
obj-y += lguest/
obj-$(CONFIG_CPU_FREQ) += cpufreq/
obj-$(CONFIG_CPU_IDLE) += cpuidle/
-obj-y += idle/
obj-$(CONFIG_MMC) += mmc/
obj-$(CONFIG_MEMSTICK) += memstick/
obj-$(CONFIG_NEW_LEDS) += leds/
diff --git a/drivers/acpi/processor_driver.c b/drivers/acpi/processor_driver.c
index deefa85..b1034a9 100644
--- a/drivers/acpi/processor_driver.c
+++ b/drivers/acpi/processor_driver.c
@@ -922,9 +922,13 @@ static int __init acpi_processor_init(void)
return -ENOMEM;
#endif
- if (!cpuidle_register_driver(&acpi_idle_driver))
+ if (!cpuidle_register_driver(&acpi_idle_driver)) {
printk(KERN_DEBUG "ACPI: %s registered with cpuidle\n",
acpi_idle_driver.name);
+ } else {
+ printk(KERN_DEBUG "ACPI: acpi_idle yielding to %s",
+ cpuidle_get_driver()->name);
+ }
result = acpi_bus_register_driver(&acpi_processor_driver);
if (result < 0)
diff --git a/drivers/idle/Kconfig b/drivers/idle/Kconfig
index f15e90a..fb5c518 100644
--- a/drivers/idle/Kconfig
+++ b/drivers/idle/Kconfig
@@ -1,3 +1,14 @@
+config INTEL_IDLE
+ tristate "Cpuidle Driver for Intel Processors"
+ depends on CPU_IDLE
+ depends on X86
+ depends on CPU_SUP_INTEL
+ depends on EXPERIMENTAL
+ help
+ Enable intel_idle, a cpuidle driver that includes knowledge of
+ native Intel hardware idle features. The acpi_idle driver
+ can be configured at the same time, in order to handle
+ processors intel_idle does not support.
menu "Memory power savings"
depends on X86_64
diff --git a/drivers/idle/Makefile b/drivers/idle/Makefile
index 5f68fc3..23d295c 100644
--- a/drivers/idle/Makefile
+++ b/drivers/idle/Makefile
@@ -1,2 +1,3 @@
obj-$(CONFIG_I7300_IDLE) += i7300_idle.o
+obj-$(CONFIG_INTEL_IDLE) += intel_idle.o
diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c
new file mode 100755
index 0000000..54f0fb4
--- /dev/null
+++ b/drivers/idle/intel_idle.c
@@ -0,0 +1,461 @@
+/*
+ * intel_idle.c - native hardware idle loop for modern Intel processors
+ *
+ * Copyright (c) 2010, Intel Corporation.
+ * Len Brown <len.brown@intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but 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.
+ */
+
+/*
+ * intel_idle is a cpuidle driver that loads on specific Intel processors
+ * in lieu of the legacy ACPI processor_idle driver. The intent is to
+ * make Linux more efficient on these processors, as intel_idle knows
+ * more than ACPI, as well as make Linux more immune to ACPI BIOS bugs.
+ */
+
+/*
+ * Design Assumptions
+ *
+ * All CPUs have same idle states as boot CPU
+ *
+ * Chipset BM_STS (bus master status) bit is a NOP
+ * for preventing entry into deep C-stats
+ */
+
+/*
+ * Known limitations
+ *
+ * The driver currently initializes for_each_online_cpu() upon modprobe.
+ * It it unaware of subsequent processors hot-added to the system.
+ * This means that if you boot with maxcpus=n and later online
+ * processors above n, those processors will use C1 only.
+ *
+ * ACPI has a .suspend hack to turn off deep c-statees during suspend
+ * to avoid complications with the lapic timer workaround.
+ * Have not seen issues with suspend, but may need same workaround here.
+ *
+ * There is currently no kernel-based automatic probing/loading mechanism
+ * if the driver is built as a module.
+ */
+
+/* un-comment DEBUG to enable pr_debug() statements */
+#define DEBUG
+
+#include <linux/kernel.h>
+#include <linux/cpuidle.h>
+#include <linux/clockchips.h>
+#include <linux/hrtimer.h> /* ktime_get_real() */
+#include <trace/events/power.h>
+#include <linux/sched.h>
+
+#define INTEL_IDLE_VERSION "0.4"
+#define PREFIX "intel_idle: "
+
+#define MWAIT_SUBSTATE_MASK (0xf)
+#define MWAIT_CSTATE_MASK (0xf)
+#define MWAIT_SUBSTATE_SIZE (4)
+#define MWAIT_MAX_NUM_CSTATES 8
+#define CPUID_MWAIT_LEAF (5)
+#define CPUID5_ECX_EXTENSIONS_SUPPORTED (0x1)
+#define CPUID5_ECX_INTERRUPT_BREAK (0x2)
+
+static struct cpuidle_driver intel_idle_driver = {
+ .name = "intel_idle",
+ .owner = THIS_MODULE,
+};
+/* intel_idle.max_cstate=0 disables driver */
+static int max_cstate = MWAIT_MAX_NUM_CSTATES - 1;
+static int power_policy = 7; /* 0 = max perf; 15 = max powersave */
+
+static unsigned int substates;
+static int (*choose_substate)(int);
+
+/* Reliable LAPIC Timer States, bit 1 for C1 etc. */
+static unsigned int lapic_timer_reliable_states;
+
+static struct cpuidle_device *intel_idle_cpuidle_devices;
+static int intel_idle(struct cpuidle_device *dev, struct cpuidle_state *state);
+
+static struct cpuidle_state *cpuidle_state_table;
+
+/*
+ * States are indexed by the cstate number,
+ * which is also the index into the MWAIT hint array.
+ * Thus C0 is a dummy.
+ */
+static struct cpuidle_state nehalem_cstates[MWAIT_MAX_NUM_CSTATES] = {
+ { /* MWAIT C0 */ },
+ { /* MWAIT C1 */
+ .name = "NHM-C1",
+ .desc = "MWAIT 0x00",
+ .driver_data = (void *) 0x00,
+ .flags = CPUIDLE_FLAG_TIME_VALID,
+ .exit_latency = 3,
+ .power_usage = 1000,
+ .target_residency = 6,
+ .enter = &intel_idle },
+ { /* MWAIT C2 */
+ .name = "NHM-C3",
+ .desc = "MWAIT 0x10",
+ .driver_data = (void *) 0x10,
+ .flags = CPUIDLE_FLAG_TIME_VALID,
+ .exit_latency = 20,
+ .power_usage = 500,
+ .target_residency = 80,
+ .enter = &intel_idle },
+ { /* MWAIT C3 */
+ .name = "NHM-C6",
+ .desc = "MWAIT 0x20",
+ .driver_data = (void *) 0x20,
+ .flags = CPUIDLE_FLAG_TIME_VALID,
+ .exit_latency = 200,
+ .power_usage = 350,
+ .target_residency = 800,
+ .enter = &intel_idle },
+};
+
+static struct cpuidle_state atom_cstates[MWAIT_MAX_NUM_CSTATES] = {
+ { /* MWAIT C0 */ },
+ { /* MWAIT C1 */
+ .name = "ATM-C1",
+ .desc = "MWAIT 0x00",
+ .driver_data = (void *) 0x00,
+ .flags = CPUIDLE_FLAG_TIME_VALID,
+ .exit_latency = 1,
+ .power_usage = 1000,
+ .target_residency = 4,
+ .enter = &intel_idle },
+ { /* MWAIT C2 */
+ .name = "ATM-C2",
+ .desc = "MWAIT 0x10",
+ .driver_data = (void *) 0x10,
+ .flags = CPUIDLE_FLAG_TIME_VALID,
+ .exit_latency = 20,
+ .power_usage = 500,
+ .target_residency = 80,
+ .enter = &intel_idle },
+ { /* MWAIT C3 */ },
+ { /* MWAIT C4 */
+ .name = "ATM-C4",
+ .desc = "MWAIT 0x30",
+ .driver_data = (void *) 0x30,
+ .flags = CPUIDLE_FLAG_TIME_VALID,
+ .exit_latency = 100,
+ .power_usage = 250,
+ .target_residency = 400,
+ .enter = &intel_idle },
+ { /* MWAIT C5 */ },
+ { /* MWAIT C6 */
+ .name = "ATM-C6",
+ .desc = "MWAIT 0x40",
+ .driver_data = (void *) 0x40,
+ .flags = CPUIDLE_FLAG_TIME_VALID,
+ .exit_latency = 200,
+ .power_usage = 150,
+ .target_residency = 800,
+ .enter = NULL }, /* disabled */
+};
+
+/*
+ * choose_tunable_substate()
+ *
+ * Run-time decision on which C-state substate to invoke
+ * If power_policy = 0, choose shallowest substate (0)
+ * If power_policy = 15, choose deepest substate
+ * If power_policy = middle, choose middle substate etc.
+ */
+static int choose_tunable_substate(int cstate)
+{
+ unsigned int num_substates;
+ unsigned int substate_choice;
+
+ power_policy &= 0xF; /* valid range: 0-15 */
+ cstate &= 7; /* valid range: 0-7 */
+
+ num_substates = (substates >> ((cstate) * 4)) & MWAIT_SUBSTATE_MASK;
+
+ if (num_substates <= 1)
+ return 0;
+
+ substate_choice = ((power_policy + (power_policy + 1) *
+ (num_substates - 1)) / 16);
+
+ return substate_choice;
+}
+
+/*
+ * choose_zero_substate()
+ */
+static int choose_zero_substate(int cstate)
+{
+ return 0;
+}
+
+/**
+ * intel_idle
+ * @dev: cpuidle_device
+ * @state: cpuidle state
+ *
+ */
+static int intel_idle(struct cpuidle_device *dev, struct cpuidle_state *state)
+{
+ unsigned long ecx = 1; /* break on interrupt flag */
+ unsigned long eax = (unsigned long)cpuidle_get_statedata(state);
+ unsigned int cstate;
+ ktime_t kt_before, kt_after;
+ s64 usec_delta;
+ int cpu = smp_processor_id();
+
+ cstate = (((eax) >> MWAIT_SUBSTATE_SIZE) & MWAIT_CSTATE_MASK) + 1;
+
+ eax = eax + (choose_substate)(cstate);
+
+ local_irq_disable();
+
+ if (!(lapic_timer_reliable_states & (1 << (cstate))))
+ clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu);
+
+ kt_before = ktime_get_real();
+
+ stop_critical_timings();
+#ifndef MODULE
+ trace_power_start(POWER_CSTATE, (eax >> 4) + 1);
+#endif
+ if (!need_resched()) {
+
+ __monitor((void *)¤t_thread_info()->flags, 0, 0);
+ smp_mb();
+ if (!need_resched())
+ __mwait(eax, ecx);
+ }
+
+ start_critical_timings();
+
+ kt_after = ktime_get_real();
+ usec_delta = ktime_to_us(ktime_sub(kt_after, kt_before));
+
+ local_irq_enable();
+
+ if (!(lapic_timer_reliable_states & (1 << (cstate))))
+ clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &cpu);
+
+ return usec_delta;
+}
+
+/*
+ * intel_idle_probe()
+ */
+static int intel_idle_probe(void)
+{
+ unsigned int eax, ebx, ecx, edx;
+
+ if (max_cstate == 0) {
+ pr_debug(PREFIX "disabled\n");
+ return -EPERM;
+ }
+
+ if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
+ return -ENODEV;
+
+ if (!boot_cpu_has(X86_FEATURE_MWAIT))
+ return -ENODEV;
+
+ if (boot_cpu_data.cpuid_level < CPUID_MWAIT_LEAF)
+ return -ENODEV;
+
+ cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &edx);
+
+ if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
+ !(ecx & CPUID5_ECX_INTERRUPT_BREAK))
+ return -ENODEV;
+#ifdef DEBUG
+ if (substates == 0) /* can over-ride via modparam */
+#endif
+ substates = edx;
+
+ pr_debug(PREFIX "MWAIT substates: 0x%x\n", substates);
+
+ if (boot_cpu_has(X86_FEATURE_ARAT)) /* Always Reliable APIC Timer */
+ lapic_timer_reliable_states = 0xFFFFFFFF;
+
+ if (boot_cpu_data.x86 != 6) /* family 6 */
+ return -ENODEV;
+
+ switch (boot_cpu_data.x86_model) {
+
+ case 0x1A: /* Core i7, Xeon 5500 series */
+ case 0x1E: /* Core i7 and i5 Processor - Lynnfield Jasper Forest */
+ case 0x1F: /* Core i7 and i5 Processor - Nehalem */
+ case 0x2E: /* Nehalem-EX Xeon */
+ lapic_timer_reliable_states = (1 << 1); /* C1 */
+
+ case 0x25: /* Westmere */
+ case 0x2C: /* Westmere */
+ cpuidle_state_table = nehalem_cstates;
+ choose_substate = choose_tunable_substate;
+ break;
+
+ case 0x1C: /* 28 - Atom Processor */
+ lapic_timer_reliable_states = (1 << 2) | (1 << 1); /* C2, C1 */
+ cpuidle_state_table = atom_cstates;
+ choose_substate = choose_zero_substate;
+ break;
+#ifdef FUTURE_USE
+ case 0x17: /* 23 - Core 2 Duo */
+ lapic_timer_reliable_states = (1 << 2) | (1 << 1); /* C2, C1 */
+#endif
+
+ default:
+ pr_debug(PREFIX "does not run on family %d model %d\n",
+ boot_cpu_data.x86, boot_cpu_data.x86_model);
+ return -ENODEV;
+ }
+
+ pr_debug(PREFIX "v" INTEL_IDLE_VERSION
+ " model 0x%X\n", boot_cpu_data.x86_model);
+
+ pr_debug(PREFIX "lapic_timer_reliable_states 0x%x\n",
+ lapic_timer_reliable_states);
+ return 0;
+}
+
+/*
+ * intel_idle_cpuidle_devices_uninit()
+ * unregister, free cpuidle_devices
+ */
+static void intel_idle_cpuidle_devices_uninit(void)
+{
+ int i;
+ struct cpuidle_device *dev;
+
+ for_each_online_cpu(i) {
+ dev = per_cpu_ptr(intel_idle_cpuidle_devices, i);
+ cpuidle_unregister_device(dev);
+ }
+
+ free_percpu(intel_idle_cpuidle_devices);
+ return;
+}
+/*
+ * intel_idle_cpuidle_devices_init()
+ * allocate, initialize, register cpuidle_devices
+ */
+static int intel_idle_cpuidle_devices_init(void)
+{
+ int i, cstate;
+ struct cpuidle_device *dev;
+
+ intel_idle_cpuidle_devices = alloc_percpu(struct cpuidle_device);
+ if (intel_idle_cpuidle_devices == NULL)
+ return -ENOMEM;
+
+ for_each_online_cpu(i) {
+ dev = per_cpu_ptr(intel_idle_cpuidle_devices, i);
+
+ dev->state_count = 1;
+
+ for (cstate = 1; cstate < MWAIT_MAX_NUM_CSTATES; ++cstate) {
+ int num_substates;
+
+ if (cstate > max_cstate) {
+ printk(PREFIX "max_cstate %d reached\n",
+ max_cstate);
+ break;
+ }
+
+ /* does the state exist in CPUID.MWAIT? */
+ num_substates = (substates >> ((cstate) * 4))
+ & MWAIT_SUBSTATE_MASK;
+ if (num_substates == 0)
+ continue;
+ /* is the state not enabled? */
+ if (cpuidle_state_table[cstate].enter == NULL) {
+ /* does the driver not know about the state? */
+ if (*cpuidle_state_table[cstate].name == '\0')
+ pr_debug(PREFIX "unaware of model 0x%x"
+ " MWAIT %d please"
+ " contact lenb@kernel.org",
+ boot_cpu_data.x86_model, cstate);
+ continue;
+ }
+
+ if ((cstate > 2) &&
+ !boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
+ mark_tsc_unstable("TSC halts in idle"
+ " states deeper than C2");
+
+ dev->states[dev->state_count] = /* structure copy */
+ cpuidle_state_table[cstate];
+
+ dev->state_count += 1;
+ }
+
+ dev->cpu = i;
+ if (cpuidle_register_device(dev)) {
+ pr_debug(PREFIX "cpuidle_register_device %d failed!\n",
+ i);
+ intel_idle_cpuidle_devices_uninit();
+ return -EIO;
+ }
+ }
+
+ return 0;
+}
+
+
+static int __init intel_idle_init(void)
+{
+ int retval;
+
+ retval = intel_idle_probe();
+ if (retval)
+ return retval;
+
+ retval = cpuidle_register_driver(&intel_idle_driver);
+ if (retval) {
+ printk(KERN_DEBUG PREFIX "intel_idle yielding to %s",
+ cpuidle_get_driver()->name);
+ return retval;
+ }
+
+ retval = intel_idle_cpuidle_devices_init();
+ if (retval) {
+ cpuidle_unregister_driver(&intel_idle_driver);
+ return retval;
+ }
+
+ return 0;
+}
+
+static void __exit intel_idle_exit(void)
+{
+ intel_idle_cpuidle_devices_uninit();
+ cpuidle_unregister_driver(&intel_idle_driver);
+
+ return;
+}
+
+module_init(intel_idle_init);
+module_exit(intel_idle_exit);
+
+module_param(power_policy, int, 0644);
+module_param(max_cstate, int, 0444);
+#ifdef DEBUG
+module_param(substates, int, 0444);
+#endif
+
+MODULE_AUTHOR("Len Brown <len.brown@intel.com>");
+MODULE_DESCRIPTION("Cpuidle driver for Intel Hardware v" INTEL_IDLE_VERSION);
+MODULE_LICENSE("GPL");
--
1.6.0.6
^ permalink raw reply related [flat|nested] 12+ messages in thread