Initial import

1 files changed, 1145 insertions, 0 deletions

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
new file mode 100644
index 000000000..39e0c8e36
--- /dev/null
+++ b/drivers/acpi/processor_idle.c
@@ -0,0 +1,1145 @@
+/*
+ * processor_idle - idle state submodule to the ACPI processor driver
+ *
+ *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
+ *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
+ *  Copyright (C) 2004, 2005 Dominik Brodowski <linux@brodo.de>
+ *  Copyright (C) 2004  Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
+ *  			- Added processor hotplug support
+ *  Copyright (C) 2005  Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
+ *  			- Added support for C3 on SMP
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or (at
+ *  your option) any later version.
+ *
+ *  This program 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
+ *  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.,
+ *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ */
+
+#include <linux/module.h>
+#include <linux/acpi.h>
+#include <linux/dmi.h>
+#include <linux/sched.h>       /* need_resched() */
+#include <linux/tick.h>
+#include <linux/cpuidle.h>
+#include <linux/syscore_ops.h>
+#include <acpi/processor.h>
+
+/*
+ * Include the apic definitions for x86 to have the APIC timer related defines
+ * available also for UP (on SMP it gets magically included via linux/smp.h).
+ * asm/acpi.h is not an option, as it would require more include magic. Also
+ * creating an empty asm-ia64/apic.h would just trade pest vs. cholera.
+ */
+#ifdef CONFIG_X86
+#include <asm/apic.h>
+#endif
+
+#define PREFIX "ACPI: "
+
+#define ACPI_PROCESSOR_CLASS            "processor"
+#define _COMPONENT              ACPI_PROCESSOR_COMPONENT
+ACPI_MODULE_NAME("processor_idle");
+
+static unsigned int max_cstate __read_mostly = ACPI_PROCESSOR_MAX_POWER;
+module_param(max_cstate, uint, 0000);
+static unsigned int nocst __read_mostly;
+module_param(nocst, uint, 0000);
+static int bm_check_disable __read_mostly;
+module_param(bm_check_disable, uint, 0000);
+
+static unsigned int latency_factor __read_mostly = 2;
+module_param(latency_factor, uint, 0644);
+
+static DEFINE_PER_CPU(struct cpuidle_device *, acpi_cpuidle_device);
+
+static DEFINE_PER_CPU(struct acpi_processor_cx * [CPUIDLE_STATE_MAX],
+								acpi_cstate);
+
+static int disabled_by_idle_boot_param(void)
+{
+	return boot_option_idle_override == IDLE_POLL ||
+		boot_option_idle_override == IDLE_HALT;
+}
+
+/*
+ * IBM ThinkPad R40e crashes mysteriously when going into C2 or C3.
+ * For now disable this. Probably a bug somewhere else.
+ *
+ * To skip this limit, boot/load with a large max_cstate limit.
+ */
+static int set_max_cstate(const struct dmi_system_id *id)
+{
+	if (max_cstate > ACPI_PROCESSOR_MAX_POWER)
+		return 0;
+
+	printk(KERN_NOTICE PREFIX "%s detected - limiting to C%ld max_cstate."
+	       " Override with \"processor.max_cstate=%d\"\n", id->ident,
+	       (long)id->driver_data, ACPI_PROCESSOR_MAX_POWER + 1);
+
+	max_cstate = (long)id->driver_data;
+
+	return 0;
+}
+
+static struct dmi_system_id processor_power_dmi_table[] = {
+	{ set_max_cstate, "Clevo 5600D", {
+	  DMI_MATCH(DMI_BIOS_VENDOR,"Phoenix Technologies LTD"),
+	  DMI_MATCH(DMI_BIOS_VERSION,"SHE845M0.86C.0013.D.0302131307")},
+	 (void *)2},
+	{ set_max_cstate, "Pavilion zv5000", {
+	  DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
+	  DMI_MATCH(DMI_PRODUCT_NAME,"Pavilion zv5000 (DS502A#ABA)")},
+	 (void *)1},
+	{ set_max_cstate, "Asus L8400B", {
+	  DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
+	  DMI_MATCH(DMI_PRODUCT_NAME,"L8400B series Notebook PC")},
+	 (void *)1},
+	{},
+};
+
+
+/*
+ * Callers should disable interrupts before the call and enable
+ * interrupts after return.
+ */
+static void acpi_safe_halt(void)
+{
+	if (!tif_need_resched()) {
+		safe_halt();
+		local_irq_disable();
+	}
+}
+
+#ifdef ARCH_APICTIMER_STOPS_ON_C3
+
+/*
+ * Some BIOS implementations switch to C3 in the published C2 state.
+ * This seems to be a common problem on AMD boxen, but other vendors
+ * are affected too. We pick the most conservative approach: we assume
+ * that the local APIC stops in both C2 and C3.
+ */
+static void lapic_timer_check_state(int state, struct acpi_processor *pr,
+				   struct acpi_processor_cx *cx)
+{
+	struct acpi_processor_power *pwr = &pr->power;
+	u8 type = local_apic_timer_c2_ok ? ACPI_STATE_C3 : ACPI_STATE_C2;
+
+	if (cpu_has(&cpu_data(pr->id), X86_FEATURE_ARAT))
+		return;
+
+	if (amd_e400_c1e_detected)
+		type = ACPI_STATE_C1;
+
+	/*
+	 * Check, if one of the previous states already marked the lapic
+	 * unstable
+	 */
+	if (pwr->timer_broadcast_on_state < state)
+		return;
+
+	if (cx->type >= type)
+		pr->power.timer_broadcast_on_state = state;
+}
+
+static void __lapic_timer_propagate_broadcast(void *arg)
+{
+	struct acpi_processor *pr = (struct acpi_processor *) arg;
+
+	if (pr->power.timer_broadcast_on_state < INT_MAX)
+		tick_broadcast_enable();
+	else
+		tick_broadcast_disable();
+}
+
+static void lapic_timer_propagate_broadcast(struct acpi_processor *pr)
+{
+	smp_call_function_single(pr->id, __lapic_timer_propagate_broadcast,
+				 (void *)pr, 1);
+}
+
+/* Power(C) State timer broadcast control */
+static void lapic_timer_state_broadcast(struct acpi_processor *pr,
+				       struct acpi_processor_cx *cx,
+				       int broadcast)
+{
+	int state = cx - pr->power.states;
+
+	if (state >= pr->power.timer_broadcast_on_state) {
+		if (broadcast)
+			tick_broadcast_enter();
+		else
+			tick_broadcast_exit();
+	}
+}
+
+#else
+
+static void lapic_timer_check_state(int state, struct acpi_processor *pr,
+				   struct acpi_processor_cx *cstate) { }
+static void lapic_timer_propagate_broadcast(struct acpi_processor *pr) { }
+static void lapic_timer_state_broadcast(struct acpi_processor *pr,
+				       struct acpi_processor_cx *cx,
+				       int broadcast)
+{
+}
+
+#endif
+
+#ifdef CONFIG_PM_SLEEP
+static u32 saved_bm_rld;
+
+static int acpi_processor_suspend(void)
+{
+	acpi_read_bit_register(ACPI_BITREG_BUS_MASTER_RLD, &saved_bm_rld);
+	return 0;
+}
+
+static void acpi_processor_resume(void)
+{
+	u32 resumed_bm_rld = 0;
+
+	acpi_read_bit_register(ACPI_BITREG_BUS_MASTER_RLD, &resumed_bm_rld);
+	if (resumed_bm_rld == saved_bm_rld)
+		return;
+
+	acpi_write_bit_register(ACPI_BITREG_BUS_MASTER_RLD, saved_bm_rld);
+}
+
+static struct syscore_ops acpi_processor_syscore_ops = {
+	.suspend = acpi_processor_suspend,
+	.resume = acpi_processor_resume,
+};
+
+void acpi_processor_syscore_init(void)
+{
+	register_syscore_ops(&acpi_processor_syscore_ops);
+}
+
+void acpi_processor_syscore_exit(void)
+{
+	unregister_syscore_ops(&acpi_processor_syscore_ops);
+}
+#endif /* CONFIG_PM_SLEEP */
+
+#if defined(CONFIG_X86)
+static void tsc_check_state(int state)
+{
+	switch (boot_cpu_data.x86_vendor) {
+	case X86_VENDOR_AMD:
+	case X86_VENDOR_INTEL:
+		/*
+		 * AMD Fam10h TSC will tick in all
+		 * C/P/S0/S1 states when this bit is set.
+		 */
+		if (boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
+			return;
+
+		/*FALL THROUGH*/
+	default:
+		/* TSC could halt in idle, so notify users */
+		if (state > ACPI_STATE_C1)
+			mark_tsc_unstable("TSC halts in idle");
+	}
+}
+#else
+static void tsc_check_state(int state) { return; }
+#endif
+
+static int acpi_processor_get_power_info_fadt(struct acpi_processor *pr)
+{
+
+	if (!pr->pblk)
+		return -ENODEV;
+
+	/* if info is obtained from pblk/fadt, type equals state */
+	pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2;
+	pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3;
+
+#ifndef CONFIG_HOTPLUG_CPU
+	/*
+	 * Check for P_LVL2_UP flag before entering C2 and above on
+	 * an SMP system.
+	 */
+	if ((num_online_cpus() > 1) &&
+	    !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED))
+		return -ENODEV;
+#endif
+
+	/* determine C2 and C3 address from pblk */
+	pr->power.states[ACPI_STATE_C2].address = pr->pblk + 4;
+	pr->power.states[ACPI_STATE_C3].address = pr->pblk + 5;
+
+	/* determine latencies from FADT */
+	pr->power.states[ACPI_STATE_C2].latency = acpi_gbl_FADT.c2_latency;
+	pr->power.states[ACPI_STATE_C3].latency = acpi_gbl_FADT.c3_latency;
+
+	/*
+	 * FADT specified C2 latency must be less than or equal to
+	 * 100 microseconds.
+	 */
+	if (acpi_gbl_FADT.c2_latency > ACPI_PROCESSOR_MAX_C2_LATENCY) {
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+			"C2 latency too large [%d]\n", acpi_gbl_FADT.c2_latency));
+		/* invalidate C2 */
+		pr->power.states[ACPI_STATE_C2].address = 0;
+	}
+
+	/*
+	 * FADT supplied C3 latency must be less than or equal to
+	 * 1000 microseconds.
+	 */
+	if (acpi_gbl_FADT.c3_latency > ACPI_PROCESSOR_MAX_C3_LATENCY) {
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+			"C3 latency too large [%d]\n", acpi_gbl_FADT.c3_latency));
+		/* invalidate C3 */
+		pr->power.states[ACPI_STATE_C3].address = 0;
+	}
+
+	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+			  "lvl2[0x%08x] lvl3[0x%08x]\n",
+			  pr->power.states[ACPI_STATE_C2].address,
+			  pr->power.states[ACPI_STATE_C3].address));
+
+	return 0;
+}
+
+static int acpi_processor_get_power_info_default(struct acpi_processor *pr)
+{
+	if (!pr->power.states[ACPI_STATE_C1].valid) {
+		/* set the first C-State to C1 */
+		/* all processors need to support C1 */
+		pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
+		pr->power.states[ACPI_STATE_C1].valid = 1;
+		pr->power.states[ACPI_STATE_C1].entry_method = ACPI_CSTATE_HALT;
+	}
+	/* the C0 state only exists as a filler in our array */
+	pr->power.states[ACPI_STATE_C0].valid = 1;
+	return 0;
+}
+
+static int acpi_processor_get_power_info_cst(struct acpi_processor *pr)
+{
+	acpi_status status;
+	u64 count;
+	int current_count;
+	int i, ret = 0;
+	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+	union acpi_object *cst;
+
+
+	if (nocst)
+		return -ENODEV;
+
+	current_count = 0;
+
+	status = acpi_evaluate_object(pr->handle, "_CST", NULL, &buffer);
+	if (ACPI_FAILURE(status)) {
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No _CST, giving up\n"));
+		return -ENODEV;
+	}
+
+	cst = buffer.pointer;
+
+	/* There must be at least 2 elements */
+	if (!cst || (cst->type != ACPI_TYPE_PACKAGE) || cst->package.count < 2) {
+		printk(KERN_ERR PREFIX "not enough elements in _CST\n");
+		ret = -EFAULT;
+		goto end;
+	}
+
+	count = cst->package.elements[0].integer.value;
+
+	/* Validate number of power states. */
+	if (count < 1 || count != cst->package.count - 1) {
+		printk(KERN_ERR PREFIX "count given by _CST is not valid\n");
+		ret = -EFAULT;
+		goto end;
+	}
+
+	/* Tell driver that at least _CST is supported. */
+	pr->flags.has_cst = 1;
+
+	for (i = 1; i <= count; i++) {
+		union acpi_object *element;
+		union acpi_object *obj;
+		struct acpi_power_register *reg;
+		struct acpi_processor_cx cx;
+
+		memset(&cx, 0, sizeof(cx));
+
+		element = &(cst->package.elements[i]);
+		if (element->type != ACPI_TYPE_PACKAGE)
+			continue;
+
+		if (element->package.count != 4)
+			continue;
+
+		obj = &(element->package.elements[0]);
+
+		if (obj->type != ACPI_TYPE_BUFFER)
+			continue;
+
+		reg = (struct acpi_power_register *)obj->buffer.pointer;
+
+		if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO &&
+		    (reg->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE))
+			continue;
+
+		/* There should be an easy way to extract an integer... */
+		obj = &(element->package.elements[1]);
+		if (obj->type != ACPI_TYPE_INTEGER)
+			continue;
+
+		cx.type = obj->integer.value;
+		/*
+		 * Some buggy BIOSes won't list C1 in _CST -
+		 * Let acpi_processor_get_power_info_default() handle them later
+		 */
+		if (i == 1 && cx.type != ACPI_STATE_C1)
+			current_count++;
+
+		cx.address = reg->address;
+		cx.index = current_count + 1;
+
+		cx.entry_method = ACPI_CSTATE_SYSTEMIO;
+		if (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) {
+			if (acpi_processor_ffh_cstate_probe
+					(pr->id, &cx, reg) == 0) {
+				cx.entry_method = ACPI_CSTATE_FFH;
+			} else if (cx.type == ACPI_STATE_C1) {
+				/*
+				 * C1 is a special case where FIXED_HARDWARE
+				 * can be handled in non-MWAIT way as well.
+				 * In that case, save this _CST entry info.
+				 * Otherwise, ignore this info and continue.
+				 */
+				cx.entry_method = ACPI_CSTATE_HALT;
+				snprintf(cx.desc, ACPI_CX_DESC_LEN, "ACPI HLT");
+			} else {
+				continue;
+			}
+			if (cx.type == ACPI_STATE_C1 &&
+			    (boot_option_idle_override == IDLE_NOMWAIT)) {
+				/*
+				 * In most cases the C1 space_id obtained from
+				 * _CST object is FIXED_HARDWARE access mode.
+				 * But when the option of idle=halt is added,
+				 * the entry_method type should be changed from
+				 * CSTATE_FFH to CSTATE_HALT.
+				 * When the option of idle=nomwait is added,
+				 * the C1 entry_method type should be
+				 * CSTATE_HALT.
+				 */
+				cx.entry_method = ACPI_CSTATE_HALT;
+				snprintf(cx.desc, ACPI_CX_DESC_LEN, "ACPI HLT");
+			}
+		} else {
+			snprintf(cx.desc, ACPI_CX_DESC_LEN, "ACPI IOPORT 0x%x",
+				 cx.address);
+		}
+
+		if (cx.type == ACPI_STATE_C1) {
+			cx.valid = 1;
+		}
+
+		obj = &(element->package.elements[2]);
+		if (obj->type != ACPI_TYPE_INTEGER)
+			continue;
+
+		cx.latency = obj->integer.value;
+
+		obj = &(element->package.elements[3]);
+		if (obj->type != ACPI_TYPE_INTEGER)
+			continue;
+
+		current_count++;
+		memcpy(&(pr->power.states[current_count]), &cx, sizeof(cx));
+
+		/*
+		 * We support total ACPI_PROCESSOR_MAX_POWER - 1
+		 * (From 1 through ACPI_PROCESSOR_MAX_POWER - 1)
+		 */
+		if (current_count >= (ACPI_PROCESSOR_MAX_POWER - 1)) {
+			printk(KERN_WARNING
+			       "Limiting number of power states to max (%d)\n",
+			       ACPI_PROCESSOR_MAX_POWER);
+			printk(KERN_WARNING
+			       "Please increase ACPI_PROCESSOR_MAX_POWER if needed.\n");
+			break;
+		}
+	}
+
+	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d power states\n",
+			  current_count));
+
+	/* Validate number of power states discovered */
+	if (current_count < 2)
+		ret = -EFAULT;
+
+      end:
+	kfree(buffer.pointer);
+
+	return ret;
+}
+
+static void acpi_processor_power_verify_c3(struct acpi_processor *pr,
+					   struct acpi_processor_cx *cx)
+{
+	static int bm_check_flag = -1;
+	static int bm_control_flag = -1;
+
+
+	if (!cx->address)
+		return;
+
+	/*
+	 * PIIX4 Erratum #18: We don't support C3 when Type-F (fast)
+	 * DMA transfers are used by any ISA device to avoid livelock.
+	 * Note that we could disable Type-F DMA (as recommended by
+	 * the erratum), but this is known to disrupt certain ISA
+	 * devices thus we take the conservative approach.
+	 */
+	else if (errata.piix4.fdma) {
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+				  "C3 not supported on PIIX4 with Type-F DMA\n"));
+		return;
+	}
+
+	/* All the logic here assumes flags.bm_check is same across all CPUs */
+	if (bm_check_flag == -1) {
+		/* Determine whether bm_check is needed based on CPU  */
+		acpi_processor_power_init_bm_check(&(pr->flags), pr->id);
+		bm_check_flag = pr->flags.bm_check;
+		bm_control_flag = pr->flags.bm_control;
+	} else {
+		pr->flags.bm_check = bm_check_flag;
+		pr->flags.bm_control = bm_control_flag;
+	}
+
+	if (pr->flags.bm_check) {
+		if (!pr->flags.bm_control) {
+			if (pr->flags.has_cst != 1) {
+				/* bus mastering control is necessary */
+				ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+					"C3 support requires BM control\n"));
+				return;
+			} else {
+				/* Here we enter C3 without bus mastering */
+				ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+					"C3 support without BM control\n"));
+			}
+		}
+	} else {
+		/*
+		 * WBINVD should be set in fadt, for C3 state to be
+		 * supported on when bm_check is not required.
+		 */
+		if (!(acpi_gbl_FADT.flags & ACPI_FADT_WBINVD)) {
+			ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+					  "Cache invalidation should work properly"
+					  " for C3 to be enabled on SMP systems\n"));
+			return;
+		}
+	}
+
+	/*
+	 * Otherwise we've met all of our C3 requirements.
+	 * Normalize the C3 latency to expidite policy.  Enable
+	 * checking of bus mastering status (bm_check) so we can
+	 * use this in our C3 policy
+	 */
+	cx->valid = 1;
+
+	/*
+	 * On older chipsets, BM_RLD needs to be set
+	 * in order for Bus Master activity to wake the
+	 * system from C3.  Newer chipsets handle DMA
+	 * during C3 automatically and BM_RLD is a NOP.
+	 * In either case, the proper way to
+	 * handle BM_RLD is to set it and leave it set.
+	 */
+	acpi_write_bit_register(ACPI_BITREG_BUS_MASTER_RLD, 1);
+
+	return;
+}
+
+static int acpi_processor_power_verify(struct acpi_processor *pr)
+{
+	unsigned int i;
+	unsigned int working = 0;
+
+	pr->power.timer_broadcast_on_state = INT_MAX;
+
+	for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {
+		struct acpi_processor_cx *cx = &pr->power.states[i];
+
+		switch (cx->type) {
+		case ACPI_STATE_C1:
+			cx->valid = 1;
+			break;
+
+		case ACPI_STATE_C2:
+			if (!cx->address)
+				break;
+			cx->valid = 1;
+			break;
+
+		case ACPI_STATE_C3:
+			acpi_processor_power_verify_c3(pr, cx);
+			break;
+		}
+		if (!cx->valid)
+			continue;
+
+		lapic_timer_check_state(i, pr, cx);
+		tsc_check_state(cx->type);
+		working++;
+	}
+
+	lapic_timer_propagate_broadcast(pr);
+
+	return (working);
+}
+
+static int acpi_processor_get_power_info(struct acpi_processor *pr)
+{
+	unsigned int i;
+	int result;
+
+
+	/* NOTE: the idle thread may not be running while calling
+	 * this function */
+
+	/* Zero initialize all the C-states info. */
+	memset(pr->power.states, 0, sizeof(pr->power.states));
+
+	result = acpi_processor_get_power_info_cst(pr);
+	if (result == -ENODEV)
+		result = acpi_processor_get_power_info_fadt(pr);
+
+	if (result)
+		return result;
+
+	acpi_processor_get_power_info_default(pr);
+
+	pr->power.count = acpi_processor_power_verify(pr);
+
+	/*
+	 * if one state of type C2 or C3 is available, mark this
+	 * CPU as being "idle manageable"
+	 */
+	for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
+		if (pr->power.states[i].valid) {
+			pr->power.count = i;
+			if (pr->power.states[i].type >= ACPI_STATE_C2)
+				pr->flags.power = 1;
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * acpi_idle_bm_check - checks if bus master activity was detected
+ */
+static int acpi_idle_bm_check(void)
+{
+	u32 bm_status = 0;
+
+	if (bm_check_disable)
+		return 0;
+
+	acpi_read_bit_register(ACPI_BITREG_BUS_MASTER_STATUS, &bm_status);
+	if (bm_status)
+		acpi_write_bit_register(ACPI_BITREG_BUS_MASTER_STATUS, 1);
+	/*
+	 * PIIX4 Erratum #18: Note that BM_STS doesn't always reflect
+	 * the true state of bus mastering activity; forcing us to
+	 * manually check the BMIDEA bit of each IDE channel.
+	 */
+	else if (errata.piix4.bmisx) {
+		if ((inb_p(errata.piix4.bmisx + 0x02) & 0x01)
+		    || (inb_p(errata.piix4.bmisx + 0x0A) & 0x01))
+			bm_status = 1;
+	}
+	return bm_status;
+}
+
+/**
+ * acpi_idle_do_entry - enter idle state using the appropriate method
+ * @cx: cstate data
+ *
+ * Caller disables interrupt before call and enables interrupt after return.
+ */
+static void acpi_idle_do_entry(struct acpi_processor_cx *cx)
+{
+	if (cx->entry_method == ACPI_CSTATE_FFH) {
+		/* Call into architectural FFH based C-state */
+		acpi_processor_ffh_cstate_enter(cx);
+	} else if (cx->entry_method == ACPI_CSTATE_HALT) {
+		acpi_safe_halt();
+	} else {
+		/* IO port based C-state */
+		inb(cx->address);
+		/* Dummy wait op - must do something useless after P_LVL2 read
+		   because chipsets cannot guarantee that STPCLK# signal
+		   gets asserted in time to freeze execution properly. */
+		inl(acpi_gbl_FADT.xpm_timer_block.address);
+	}
+}
+
+/**
+ * acpi_idle_play_dead - enters an ACPI state for long-term idle (i.e. off-lining)
+ * @dev: the target CPU
+ * @index: the index of suggested state
+ */
+static int acpi_idle_play_dead(struct cpuidle_device *dev, int index)
+{
+	struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
+
+	ACPI_FLUSH_CPU_CACHE();
+
+	while (1) {
+
+		if (cx->entry_method == ACPI_CSTATE_HALT)
+			safe_halt();
+		else if (cx->entry_method == ACPI_CSTATE_SYSTEMIO) {
+			inb(cx->address);
+			/* See comment in acpi_idle_do_entry() */
+			inl(acpi_gbl_FADT.xpm_timer_block.address);
+		} else
+			return -ENODEV;
+	}
+
+	/* Never reached */
+	return 0;
+}
+
+static bool acpi_idle_fallback_to_c1(struct acpi_processor *pr)
+{
+	return IS_ENABLED(CONFIG_HOTPLUG_CPU) && !pr->flags.has_cst &&
+		!(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED);
+}
+
+static int c3_cpu_count;
+static DEFINE_RAW_SPINLOCK(c3_lock);
+
+/**
+ * acpi_idle_enter_bm - enters C3 with proper BM handling
+ * @pr: Target processor
+ * @cx: Target state context
+ * @timer_bc: Whether or not to change timer mode to broadcast
+ */
+static void acpi_idle_enter_bm(struct acpi_processor *pr,
+			       struct acpi_processor_cx *cx, bool timer_bc)
+{
+	acpi_unlazy_tlb(smp_processor_id());
+
+	/*
+	 * Must be done before busmaster disable as we might need to
+	 * access HPET !
+	 */
+	if (timer_bc)
+		lapic_timer_state_broadcast(pr, cx, 1);
+
+	/*
+	 * disable bus master
+	 * bm_check implies we need ARB_DIS
+	 * bm_control implies whether we can do ARB_DIS
+	 *
+	 * That leaves a case where bm_check is set and bm_control is
+	 * not set. In that case we cannot do much, we enter C3
+	 * without doing anything.
+	 */
+	if (pr->flags.bm_control) {
+		raw_spin_lock(&c3_lock);
+		c3_cpu_count++;
+		/* Disable bus master arbitration when all CPUs are in C3 */
+		if (c3_cpu_count == num_online_cpus())
+			acpi_write_bit_register(ACPI_BITREG_ARB_DISABLE, 1);
+		raw_spin_unlock(&c3_lock);
+	}
+
+	acpi_idle_do_entry(cx);
+
+	/* Re-enable bus master arbitration */
+	if (pr->flags.bm_control) {
+		raw_spin_lock(&c3_lock);
+		acpi_write_bit_register(ACPI_BITREG_ARB_DISABLE, 0);
+		c3_cpu_count--;
+		raw_spin_unlock(&c3_lock);
+	}
+
+	if (timer_bc)
+		lapic_timer_state_broadcast(pr, cx, 0);
+}
+
+static int acpi_idle_enter(struct cpuidle_device *dev,
+			   struct cpuidle_driver *drv, int index)
+{
+	struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
+	struct acpi_processor *pr;
+
+	pr = __this_cpu_read(processors);
+	if (unlikely(!pr))
+		return -EINVAL;
+
+	if (cx->type != ACPI_STATE_C1) {
+		if (acpi_idle_fallback_to_c1(pr) && num_online_cpus() > 1) {
+			index = CPUIDLE_DRIVER_STATE_START;
+			cx = per_cpu(acpi_cstate[index], dev->cpu);
+		} else if (cx->type == ACPI_STATE_C3 && pr->flags.bm_check) {
+			if (cx->bm_sts_skip || !acpi_idle_bm_check()) {
+				acpi_idle_enter_bm(pr, cx, true);
+				return index;
+			} else if (drv->safe_state_index >= 0) {
+				index = drv->safe_state_index;
+				cx = per_cpu(acpi_cstate[index], dev->cpu);
+			} else {
+				acpi_safe_halt();
+				return -EBUSY;
+			}
+		}
+	}
+
+	lapic_timer_state_broadcast(pr, cx, 1);
+
+	if (cx->type == ACPI_STATE_C3)
+		ACPI_FLUSH_CPU_CACHE();
+
+	acpi_idle_do_entry(cx);
+
+	lapic_timer_state_broadcast(pr, cx, 0);
+
+	return index;
+}
+
+static void acpi_idle_enter_freeze(struct cpuidle_device *dev,
+				   struct cpuidle_driver *drv, int index)
+{
+	struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
+
+	if (cx->type == ACPI_STATE_C3) {
+		struct acpi_processor *pr = __this_cpu_read(processors);
+
+		if (unlikely(!pr))
+			return;
+
+		if (pr->flags.bm_check) {
+			acpi_idle_enter_bm(pr, cx, false);
+			return;
+		} else {
+			ACPI_FLUSH_CPU_CACHE();
+		}
+	}
+	acpi_idle_do_entry(cx);
+}
+
+struct cpuidle_driver acpi_idle_driver = {
+	.name =		"acpi_idle",
+	.owner =	THIS_MODULE,
+};
+
+/**
+ * acpi_processor_setup_cpuidle_cx - prepares and configures CPUIDLE
+ * device i.e. per-cpu data
+ *
+ * @pr: the ACPI processor
+ * @dev : the cpuidle device
+ */
+static int acpi_processor_setup_cpuidle_cx(struct acpi_processor *pr,
+					   struct cpuidle_device *dev)
+{
+	int i, count = CPUIDLE_DRIVER_STATE_START;
+	struct acpi_processor_cx *cx;
+
+	if (!pr->flags.power_setup_done)
+		return -EINVAL;
+
+	if (pr->flags.power == 0) {
+		return -EINVAL;
+	}
+
+	if (!dev)
+		return -EINVAL;
+
+	dev->cpu = pr->id;
+
+	if (max_cstate == 0)
+		max_cstate = 1;
+
+	for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {
+		cx = &pr->power.states[i];
+
+		if (!cx->valid)
+			continue;
+
+		per_cpu(acpi_cstate[count], dev->cpu) = cx;
+
+		count++;
+		if (count == CPUIDLE_STATE_MAX)
+			break;
+	}
+
+	if (!count)
+		return -EINVAL;
+
+	return 0;
+}
+
+/**
+ * acpi_processor_setup_cpuidle states- prepares and configures cpuidle
+ * global state data i.e. idle routines
+ *
+ * @pr: the ACPI processor
+ */
+static int acpi_processor_setup_cpuidle_states(struct acpi_processor *pr)
+{
+	int i, count = CPUIDLE_DRIVER_STATE_START;
+	struct acpi_processor_cx *cx;
+	struct cpuidle_state *state;
+	struct cpuidle_driver *drv = &acpi_idle_driver;
+
+	if (!pr->flags.power_setup_done)
+		return -EINVAL;
+
+	if (pr->flags.power == 0)
+		return -EINVAL;
+
+	drv->safe_state_index = -1;
+	for (i = CPUIDLE_DRIVER_STATE_START; i < CPUIDLE_STATE_MAX; i++) {
+		drv->states[i].name[0] = '\0';
+		drv->states[i].desc[0] = '\0';
+	}
+
+	if (max_cstate == 0)
+		max_cstate = 1;
+
+	for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {
+		cx = &pr->power.states[i];
+
+		if (!cx->valid)
+			continue;
+
+		state = &drv->states[count];
+		snprintf(state->name, CPUIDLE_NAME_LEN, "C%d", i);
+		strncpy(state->desc, cx->desc, CPUIDLE_DESC_LEN);
+		state->exit_latency = cx->latency;
+		state->target_residency = cx->latency * latency_factor;
+		state->enter = acpi_idle_enter;
+
+		state->flags = 0;
+		if (cx->type == ACPI_STATE_C1 || cx->type == ACPI_STATE_C2) {
+			state->enter_dead = acpi_idle_play_dead;
+			drv->safe_state_index = count;
+		}
+		/*
+		 * Halt-induced C1 is not good for ->enter_freeze, because it
+		 * re-enables interrupts on exit.  Moreover, C1 is generally not
+		 * particularly interesting from the suspend-to-idle angle, so
+		 * avoid C1 and the situations in which we may need to fall back
+		 * to it altogether.
+		 */
+		if (cx->type != ACPI_STATE_C1 && !acpi_idle_fallback_to_c1(pr))
+			state->enter_freeze = acpi_idle_enter_freeze;
+
+		count++;
+		if (count == CPUIDLE_STATE_MAX)
+			break;
+	}
+
+	drv->state_count = count;
+
+	if (!count)
+		return -EINVAL;
+
+	return 0;
+}
+
+int acpi_processor_hotplug(struct acpi_processor *pr)
+{
+	int ret = 0;
+	struct cpuidle_device *dev;
+
+	if (disabled_by_idle_boot_param())
+		return 0;
+
+	if (nocst)
+		return -ENODEV;
+
+	if (!pr->flags.power_setup_done)
+		return -ENODEV;
+
+	dev = per_cpu(acpi_cpuidle_device, pr->id);
+	cpuidle_pause_and_lock();
+	cpuidle_disable_device(dev);
+	acpi_processor_get_power_info(pr);
+	if (pr->flags.power) {
+		acpi_processor_setup_cpuidle_cx(pr, dev);
+		ret = cpuidle_enable_device(dev);
+	}
+	cpuidle_resume_and_unlock();
+
+	return ret;
+}
+
+int acpi_processor_cst_has_changed(struct acpi_processor *pr)
+{
+	int cpu;
+	struct acpi_processor *_pr;
+	struct cpuidle_device *dev;
+
+	if (disabled_by_idle_boot_param())
+		return 0;
+
+	if (nocst)
+		return -ENODEV;
+
+	if (!pr->flags.power_setup_done)
+		return -ENODEV;
+
+	/*
+	 * FIXME:  Design the ACPI notification to make it once per
+	 * system instead of once per-cpu.  This condition is a hack
+	 * to make the code that updates C-States be called once.
+	 */
+
+	if (pr->id == 0 && cpuidle_get_driver() == &acpi_idle_driver) {
+
+		/* Protect against cpu-hotplug */
+		get_online_cpus();
+		cpuidle_pause_and_lock();
+
+		/* Disable all cpuidle devices */
+		for_each_online_cpu(cpu) {
+			_pr = per_cpu(processors, cpu);
+			if (!_pr || !_pr->flags.power_setup_done)
+				continue;
+			dev = per_cpu(acpi_cpuidle_device, cpu);
+			cpuidle_disable_device(dev);
+		}
+
+		/* Populate Updated C-state information */
+		acpi_processor_get_power_info(pr);
+		acpi_processor_setup_cpuidle_states(pr);
+
+		/* Enable all cpuidle devices */
+		for_each_online_cpu(cpu) {
+			_pr = per_cpu(processors, cpu);
+			if (!_pr || !_pr->flags.power_setup_done)
+				continue;
+			acpi_processor_get_power_info(_pr);
+			if (_pr->flags.power) {
+				dev = per_cpu(acpi_cpuidle_device, cpu);
+				acpi_processor_setup_cpuidle_cx(_pr, dev);
+				cpuidle_enable_device(dev);
+			}
+		}
+		cpuidle_resume_and_unlock();
+		put_online_cpus();
+	}
+
+	return 0;
+}
+
+static int acpi_processor_registered;
+
+int acpi_processor_power_init(struct acpi_processor *pr)
+{
+	acpi_status status;
+	int retval;
+	struct cpuidle_device *dev;
+	static int first_run;
+
+	if (disabled_by_idle_boot_param())
+		return 0;
+
+	if (!first_run) {
+		dmi_check_system(processor_power_dmi_table);
+		max_cstate = acpi_processor_cstate_check(max_cstate);
+		if (max_cstate < ACPI_C_STATES_MAX)
+			printk(KERN_NOTICE
+			       "ACPI: processor limited to max C-state %d\n",
+			       max_cstate);
+		first_run++;
+	}
+
+	if (acpi_gbl_FADT.cst_control && !nocst) {
+		status =
+		    acpi_os_write_port(acpi_gbl_FADT.smi_command, acpi_gbl_FADT.cst_control, 8);
+		if (ACPI_FAILURE(status)) {
+			ACPI_EXCEPTION((AE_INFO, status,
+					"Notifying BIOS of _CST ability failed"));
+		}
+	}
+
+	acpi_processor_get_power_info(pr);
+	pr->flags.power_setup_done = 1;
+
+	/*
+	 * Install the idle handler if processor power management is supported.
+	 * Note that we use previously set idle handler will be used on
+	 * platforms that only support C1.
+	 */
+	if (pr->flags.power) {
+		/* Register acpi_idle_driver if not already registered */
+		if (!acpi_processor_registered) {
+			acpi_processor_setup_cpuidle_states(pr);
+			retval = cpuidle_register_driver(&acpi_idle_driver);
+			if (retval)
+				return retval;
+			printk(KERN_DEBUG "ACPI: %s registered with cpuidle\n",
+					acpi_idle_driver.name);
+		}
+
+		dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+		if (!dev)
+			return -ENOMEM;
+		per_cpu(acpi_cpuidle_device, pr->id) = dev;
+
+		acpi_processor_setup_cpuidle_cx(pr, dev);
+
+		/* Register per-cpu cpuidle_device. Cpuidle driver
+		 * must already be registered before registering device
+		 */
+		retval = cpuidle_register_device(dev);
+		if (retval) {
+			if (acpi_processor_registered == 0)
+				cpuidle_unregister_driver(&acpi_idle_driver);
+			return retval;
+		}
+		acpi_processor_registered++;
+	}
+	return 0;
+}
+
+int acpi_processor_power_exit(struct acpi_processor *pr)
+{
+	struct cpuidle_device *dev = per_cpu(acpi_cpuidle_device, pr->id);
+
+	if (disabled_by_idle_boot_param())
+		return 0;
+
+	if (pr->flags.power) {
+		cpuidle_unregister_device(dev);
+		acpi_processor_registered--;
+		if (acpi_processor_registered == 0)
+			cpuidle_unregister_driver(&acpi_idle_driver);
+	}
+
+	pr->flags.power_setup_done = 0;
+	return 0;
+}