Merge branch 'i7300_idle' into test

10 files changed, 713 insertions, 0 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index 4b7d8f291cd4..5edb541c2fad 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2078,6 +2078,12 @@ L:	linux-ide@vger.kernel.org
 L:	linux-scsi@vger.kernel.org
 S:	Orphan
 
+IDLE-I7300
+P:	Andy Henroid
+M:	andrew.d.henroid@intel.com
+L:	linux-pm@lists.linux-foundation.org
+S:	Supported
+
 IEEE 1394 SUBSYSTEM (drivers/ieee1394)
 P:	Ben Collins
 M:	ben.collins@ubuntu.com
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index f8caf040650e..540a78242034 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1539,6 +1539,8 @@ source "arch/x86/kernel/cpu/cpufreq/Kconfig"
 
 source "drivers/cpuidle/Kconfig"
 
+source "drivers/idle/Kconfig"
+
 endmenu
 
 
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index e12e0e4dd256..3e3d503eadcf 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -62,6 +62,13 @@ void idle_notifier_register(struct notifier_block *n)
 {
 	atomic_notifier_chain_register(&idle_notifier, n);
 }
+EXPORT_SYMBOL_GPL(idle_notifier_register);
+
+void idle_notifier_unregister(struct notifier_block *n)
+{
+	atomic_notifier_chain_unregister(&idle_notifier, n);
+}
+EXPORT_SYMBOL_GPL(idle_notifier_unregister);
 
 void enter_idle(void)
 {
diff --git a/drivers/Makefile b/drivers/Makefile
index 2735bde73475..f443a8a9d46e 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -82,6 +82,7 @@ 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/dma/ioat_dma.c b/drivers/dma/ioat_dma.c
index bc8c6e3470ca..f8396cafa05f 100644
--- a/drivers/dma/ioat_dma.c
+++ b/drivers/dma/ioat_dma.c
@@ -171,6 +171,9 @@ static int ioat_dma_enumerate_channels(struct ioatdma_device *device)
 	xfercap_scale = readb(device->reg_base + IOAT_XFERCAP_OFFSET);
 	xfercap = (xfercap_scale == 0 ? -1 : (1UL << xfercap_scale));
 
+#if CONFIG_I7300_IDLE_IOAT_CHANNEL
+	device->common.chancnt--;
+#endif
 	for (i = 0; i < device->common.chancnt; i++) {
 		ioat_chan = kzalloc(sizeof(*ioat_chan), GFP_KERNEL);
 		if (!ioat_chan) {
diff --git a/drivers/idle/Kconfig b/drivers/idle/Kconfig
new file mode 100644
index 000000000000..f5b26dd579e4
--- /dev/null
+++ b/drivers/idle/Kconfig
@@ -0,0 +1,16 @@
+
+menu "Memory power savings"
+
+config I7300_IDLE_IOAT_CHANNEL
+	bool
+
+config I7300_IDLE
+	tristate "Intel chipset idle power saving driver"
+	select I7300_IDLE_IOAT_CHANNEL
+	depends on X86_64
+	help
+	  Enable idle power savings with certain Intel server chipsets.
+	  The chipset must have I/O AT support, such as the Intel 7300.
+	  The power savings depends on the type and quantity of DRAM devices.
+
+endmenu
diff --git a/drivers/idle/Makefile b/drivers/idle/Makefile
new file mode 100644
index 000000000000..5f68fc377e21
--- /dev/null
+++ b/drivers/idle/Makefile
@@ -0,0 +1,2 @@
+obj-$(CONFIG_I7300_IDLE)			+= i7300_idle.o
+
diff --git a/drivers/idle/i7300_idle.c b/drivers/idle/i7300_idle.c
new file mode 100644
index 000000000000..59d1bbc3cd3c
--- /dev/null
+++ b/drivers/idle/i7300_idle.c
@@ -0,0 +1,674 @@
+/*
+ * (C) Copyright 2008 Intel Corporation
+ * Authors:
+ * Andy Henroid <andrew.d.henroid@intel.com>
+ * Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
+ */
+
+/*
+ * Save DIMM power on Intel 7300-based platforms when all CPUs/cores
+ * are idle, using the DIMM thermal throttling capability.
+ *
+ * This driver depends on the Intel integrated DMA controller (I/O AT).
+ * If the driver for I/O AT (drivers/dma/ioatdma*) is also enabled,
+ * this driver should work cooperatively.
+ */
+
+/* #define DEBUG */
+
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/sched.h>
+#include <linux/notifier.h>
+#include <linux/cpumask.h>
+#include <linux/ktime.h>
+#include <linux/delay.h>
+#include <linux/debugfs.h>
+#include <linux/stop_machine.h>
+
+#include <asm/idle.h>
+
+#include "../dma/ioatdma_hw.h"
+#include "../dma/ioatdma_registers.h"
+
+#define I7300_IDLE_DRIVER_VERSION	"1.55"
+#define I7300_PRINT			"i7300_idle:"
+
+static int debug;
+module_param_named(debug, debug, uint, 0644);
+MODULE_PARM_DESC(debug, "Enable debug printks in this driver");
+
+#define dprintk(fmt, arg...) \
+	do { if (debug) printk(KERN_INFO I7300_PRINT fmt, ##arg); } while (0)
+
+/*
+ * Value to set THRTLOW to when initiating throttling
+ *  0 = No throttling
+ *  1 = Throttle when > 4 activations per eval window (Maximum throttling)
+ *  2 = Throttle when > 8 activations
+ *  168 = Throttle when > 168 activations (Minimum throttling)
+ */
+#define MAX_THRTLWLIMIT		168
+static uint i7300_idle_thrtlowlm = 1;
+module_param_named(thrtlwlimit, i7300_idle_thrtlowlm, uint, 0644);
+MODULE_PARM_DESC(thrtlwlimit,
+		"Value for THRTLOWLM activation field "
+		"(0 = disable throttle, 1 = Max throttle, 168 = Min throttle)");
+
+/*
+ * simple invocation and duration statistics
+ */
+static unsigned long total_starts;
+static unsigned long total_us;
+
+#ifdef DEBUG
+static unsigned long past_skip;
+#endif
+
+static struct pci_dev *fbd_dev;
+
+static spinlock_t i7300_idle_lock;
+static int i7300_idle_active;
+
+static u8 i7300_idle_thrtctl_saved;
+static u8 i7300_idle_thrtlow_saved;
+static u32 i7300_idle_mc_saved;
+
+static cpumask_t idle_cpumask;
+static ktime_t start_ktime;
+static unsigned long avg_idle_us;
+
+static struct dentry *debugfs_dir;
+
+/* Begin: I/O AT Helper routines */
+
+#define IOAT_CHANBASE(ioat_ctl, chan) (ioat_ctl + 0x80 + 0x80 * chan)
+/* Snoop control (disable snoops when coherency is not important) */
+#define IOAT_DESC_SADDR_SNP_CTL (1UL << 1)
+#define IOAT_DESC_DADDR_SNP_CTL (1UL << 2)
+
+static struct pci_dev *ioat_dev;
+static struct ioat_dma_descriptor *ioat_desc; /* I/O AT desc & data (1 page) */
+static unsigned long ioat_desc_phys;
+static u8 *ioat_iomap; /* I/O AT memory-mapped control regs (aka CB_BAR) */
+static u8 *ioat_chanbase;
+
+/* Start I/O AT memory copy */
+static int i7300_idle_ioat_start(void)
+{
+	u32 err;
+	/* Clear error (due to circular descriptor pointer) */
+	err = readl(ioat_chanbase + IOAT_CHANERR_OFFSET);
+	if (err)
+		writel(err, ioat_chanbase + IOAT_CHANERR_OFFSET);
+
+	writeb(IOAT_CHANCMD_START, ioat_chanbase + IOAT1_CHANCMD_OFFSET);
+	return 0;
+}
+
+/* Stop I/O AT memory copy */
+static void i7300_idle_ioat_stop(void)
+{
+	int i;
+	u8 sts;
+
+	for (i = 0; i < 5; i++) {
+		writeb(IOAT_CHANCMD_RESET,
+			ioat_chanbase + IOAT1_CHANCMD_OFFSET);
+
+		udelay(10);
+
+		sts = readq(ioat_chanbase + IOAT1_CHANSTS_OFFSET) &
+			IOAT_CHANSTS_DMA_TRANSFER_STATUS;
+
+		if (sts != IOAT_CHANSTS_DMA_TRANSFER_STATUS_ACTIVE)
+			break;
+
+	}
+
+	if (i == 5)
+		dprintk("failed to suspend+reset I/O AT after 5 retries\n");
+
+}
+
+/* Test I/O AT by copying 1024 byte from 2k to 1k */
+static int __init i7300_idle_ioat_selftest(u8 *ctl,
+		struct ioat_dma_descriptor *desc, unsigned long desc_phys)
+{
+	u64 chan_sts;
+
+	memset(desc, 0, 2048);
+	memset((u8 *) desc + 2048, 0xab, 1024);
+
+	desc[0].size = 1024;
+	desc[0].ctl = 0;
+	desc[0].src_addr = desc_phys + 2048;
+	desc[0].dst_addr = desc_phys + 1024;
+	desc[0].next = 0;
+
+	writeb(IOAT_CHANCMD_RESET, ioat_chanbase + IOAT1_CHANCMD_OFFSET);
+	writeb(IOAT_CHANCMD_START, ioat_chanbase + IOAT1_CHANCMD_OFFSET);
+
+	udelay(1000);
+
+	chan_sts = readq(ioat_chanbase + IOAT1_CHANSTS_OFFSET) &
+			IOAT_CHANSTS_DMA_TRANSFER_STATUS;
+
+	if (chan_sts != IOAT_CHANSTS_DMA_TRANSFER_STATUS_DONE) {
+		/* Not complete, reset the channel */
+		writeb(IOAT_CHANCMD_RESET,
+		       ioat_chanbase + IOAT1_CHANCMD_OFFSET);
+		return -1;
+	}
+
+	if (*(u32 *) ((u8 *) desc + 3068) != 0xabababab ||
+	    *(u32 *) ((u8 *) desc + 2044) != 0xabababab) {
+		dprintk("Data values src 0x%x, dest 0x%x, memset 0x%x\n",
+			*(u32 *) ((u8 *) desc + 2048),
+			*(u32 *) ((u8 *) desc + 1024),
+			*(u32 *) ((u8 *) desc + 3072));
+		return -1;
+	}
+	return 0;
+}
+
+static struct device dummy_dma_dev = {
+	.bus_id = "fallback device",
+	.coherent_dma_mask = DMA_64BIT_MASK,
+	.dma_mask = &dummy_dma_dev.coherent_dma_mask,
+};
+
+/* Setup and initialize I/O AT */
+/* This driver needs I/O AT as the throttling takes effect only when there is
+ * some memory activity. We use I/O AT to set up a dummy copy, while all CPUs
+ * go idle and memory is throttled.
+ */
+static int __init i7300_idle_ioat_init(void)
+{
+	u8 ver, chan_count, ioat_chan;
+	u16 chan_ctl;
+
+	ioat_iomap = (u8 *) ioremap_nocache(pci_resource_start(ioat_dev, 0),
+					    pci_resource_len(ioat_dev, 0));
+
+	if (!ioat_iomap) {
+		printk(KERN_ERR I7300_PRINT "failed to map I/O AT registers\n");
+		goto err_ret;
+	}
+
+	ver = readb(ioat_iomap + IOAT_VER_OFFSET);
+	if (ver != IOAT_VER_1_2) {
+		printk(KERN_ERR I7300_PRINT "unknown I/O AT version (%u.%u)\n",
+			ver >> 4, ver & 0xf);
+		goto err_unmap;
+	}
+
+	chan_count = readb(ioat_iomap + IOAT_CHANCNT_OFFSET);
+	if (!chan_count) {
+		printk(KERN_ERR I7300_PRINT "unexpected # of I/O AT channels "
+			"(%u)\n",
+			chan_count);
+		goto err_unmap;
+	}
+
+	ioat_chan = chan_count - 1;
+	ioat_chanbase = IOAT_CHANBASE(ioat_iomap, ioat_chan);
+
+	chan_ctl = readw(ioat_chanbase + IOAT_CHANCTRL_OFFSET);
+	if (chan_ctl & IOAT_CHANCTRL_CHANNEL_IN_USE) {
+		printk(KERN_ERR I7300_PRINT "channel %d in use\n", ioat_chan);
+		goto err_unmap;
+	}
+
+	writew(IOAT_CHANCTRL_CHANNEL_IN_USE,
+		ioat_chanbase + IOAT_CHANCTRL_OFFSET);
+
+	ioat_desc = (struct ioat_dma_descriptor *)dma_alloc_coherent(
+			&dummy_dma_dev, 4096,
+			(dma_addr_t *)&ioat_desc_phys, GFP_KERNEL);
+	if (!ioat_desc) {
+		printk(KERN_ERR I7300_PRINT "failed to allocate I/O AT desc\n");
+		goto err_mark_unused;
+	}
+
+	writel(ioat_desc_phys & 0xffffffffUL,
+	       ioat_chanbase + IOAT1_CHAINADDR_OFFSET_LOW);
+	writel(ioat_desc_phys >> 32,
+	       ioat_chanbase + IOAT1_CHAINADDR_OFFSET_HIGH);
+
+	if (i7300_idle_ioat_selftest(ioat_iomap, ioat_desc, ioat_desc_phys)) {
+		printk(KERN_ERR I7300_PRINT "I/O AT self-test failed\n");
+		goto err_free;
+	}
+
+	/* Setup circular I/O AT descriptor chain */
+	ioat_desc[0].ctl = IOAT_DESC_SADDR_SNP_CTL | IOAT_DESC_DADDR_SNP_CTL;
+	ioat_desc[0].src_addr = ioat_desc_phys + 2048;
+	ioat_desc[0].dst_addr = ioat_desc_phys + 3072;
+	ioat_desc[0].size = 128;
+	ioat_desc[0].next = ioat_desc_phys + sizeof(struct ioat_dma_descriptor);
+
+	ioat_desc[1].ctl = ioat_desc[0].ctl;
+	ioat_desc[1].src_addr = ioat_desc[0].src_addr;
+	ioat_desc[1].dst_addr = ioat_desc[0].dst_addr;
+	ioat_desc[1].size = ioat_desc[0].size;
+	ioat_desc[1].next = ioat_desc_phys;
+
+	return 0;
+
+err_free:
+	dma_free_coherent(&dummy_dma_dev, 4096, (void *)ioat_desc, 0);
+err_mark_unused:
+	writew(0, ioat_chanbase + IOAT_CHANCTRL_OFFSET);
+err_unmap:
+	iounmap(ioat_iomap);
+err_ret:
+	return -ENODEV;
+}
+
+/* Cleanup I/O AT */
+static void __exit i7300_idle_ioat_exit(void)
+{
+	int i;
+	u64 chan_sts;
+
+	i7300_idle_ioat_stop();
+
+	/* Wait for a while for the channel to halt before releasing */
+	for (i = 0; i < 10; i++) {
+		writeb(IOAT_CHANCMD_RESET,
+		       ioat_chanbase + IOAT1_CHANCMD_OFFSET);
+
+		chan_sts = readq(ioat_chanbase + IOAT1_CHANSTS_OFFSET) &
+			IOAT_CHANSTS_DMA_TRANSFER_STATUS;
+
+		if (chan_sts != IOAT_CHANSTS_DMA_TRANSFER_STATUS_ACTIVE) {
+			writew(0, ioat_chanbase + IOAT_CHANCTRL_OFFSET);
+			break;
+		}
+		udelay(1000);
+	}
+
+	chan_sts = readq(ioat_chanbase + IOAT1_CHANSTS_OFFSET) &
+			IOAT_CHANSTS_DMA_TRANSFER_STATUS;
+
+	/*
+	 * We tried to reset multiple times. If IO A/T channel is still active
+	 * flag an error and return without cleanup. Memory leak is better
+	 * than random corruption in that extreme error situation.
+	 */
+	if (chan_sts == IOAT_CHANSTS_DMA_TRANSFER_STATUS_ACTIVE) {
+		printk(KERN_ERR I7300_PRINT "Unable to stop IO A/T channels."
+			" Not freeing resources\n");
+		return;
+	}
+
+	dma_free_coherent(&dummy_dma_dev, 4096, (void *)ioat_desc, 0);
+	iounmap(ioat_iomap);
+}
+
+/* End: I/O AT Helper routines */
+
+#define DIMM_THRTLOW 0x64
+#define DIMM_THRTCTL 0x67
+#define DIMM_THRTCTL_THRMHUNT (1UL << 0)
+#define DIMM_MC 0x40
+#define DIMM_GTW_MODE (1UL << 17)
+#define DIMM_GBLACT 0x60
+
+/*
+ * Keep track of an exponential-decaying average of recent idle durations.
+ * The latest duration gets DURATION_WEIGHT_PCT percentage weight
+ * in this average, with the old average getting the remaining weight.
+ *
+ * High weights emphasize recent history, low weights include long history.
+ */
+#define DURATION_WEIGHT_PCT 55
+
+/*
+ * When the decaying average of recent durations or the predicted duration
+ * of the next timer interrupt is shorter than duration_threshold, the
+ * driver will decline to throttle.
+ */
+#define DURATION_THRESHOLD_US 100
+
+
+/* Store DIMM thermal throttle configuration */
+static int i7300_idle_thrt_save(void)
+{
+	u32 new_mc_val;
+	u8 gblactlm;
+
+	pci_read_config_byte(fbd_dev, DIMM_THRTCTL, &i7300_idle_thrtctl_saved);
+	pci_read_config_byte(fbd_dev, DIMM_THRTLOW, &i7300_idle_thrtlow_saved);
+	pci_read_config_dword(fbd_dev, DIMM_MC, &i7300_idle_mc_saved);
+	/*
+	 * Make sure we have Global Throttling Window Mode set to have a
+	 * "short" window. This (mostly) works around an issue where
+	 * throttling persists until the end of the global throttling window
+	 * size. On the tested system, this was resulting in a maximum of
+	 * 64 ms to exit throttling (average 32 ms). The actual numbers
+	 * depends on system frequencies. Setting the short window reduces
+	 * this by a factor of 4096.
+	 *
+	 * We will only do this only if the system is set for
+	 * unlimited-activations while in open-loop throttling (i.e., when
+	 * Global Activation Throttle Limit is zero).
+	 */
+	pci_read_config_byte(fbd_dev, DIMM_GBLACT, &gblactlm);
+	dprintk("thrtctl_saved = 0x%02x, thrtlow_saved = 0x%02x\n",
+		i7300_idle_thrtctl_saved,
+		i7300_idle_thrtlow_saved);
+	dprintk("mc_saved = 0x%08x, gblactlm = 0x%02x\n",
+		i7300_idle_mc_saved,
+		gblactlm);
+	if (gblactlm == 0) {
+		new_mc_val = i7300_idle_mc_saved | DIMM_GTW_MODE;
+		pci_write_config_dword(fbd_dev, DIMM_MC, new_mc_val);
+		return 0;
+	} else {
+		dprintk("could not set GTW_MODE = 1 (OLTT enabled)\n");
+		return -ENODEV;
+	}
+}
+
+/* Restore DIMM thermal throttle configuration */
+static void i7300_idle_thrt_restore(void)
+{
+	pci_write_config_dword(fbd_dev, DIMM_MC, i7300_idle_mc_saved);
+	pci_write_config_byte(fbd_dev, DIMM_THRTLOW, i7300_idle_thrtlow_saved);
+	pci_write_config_byte(fbd_dev, DIMM_THRTCTL, i7300_idle_thrtctl_saved);
+}
+
+/* Enable DIMM thermal throttling */
+static void i7300_idle_start(void)
+{
+	u8 new_ctl;
+	u8 limit;
+
+	new_ctl = i7300_idle_thrtctl_saved & ~DIMM_THRTCTL_THRMHUNT;
+	pci_write_config_byte(fbd_dev, DIMM_THRTCTL, new_ctl);
+
+	limit = i7300_idle_thrtlowlm;
+	if (unlikely(limit > MAX_THRTLWLIMIT))
+		limit = MAX_THRTLWLIMIT;
+
+	pci_write_config_byte(fbd_dev, DIMM_THRTLOW, limit);
+
+	new_ctl = i7300_idle_thrtctl_saved | DIMM_THRTCTL_THRMHUNT;
+	pci_write_config_byte(fbd_dev, DIMM_THRTCTL, new_ctl);
+}
+
+/* Disable DIMM thermal throttling */
+static void i7300_idle_stop(void)
+{
+	u8 new_ctl;
+	u8 got_ctl;
+
+	new_ctl = i7300_idle_thrtctl_saved & ~DIMM_THRTCTL_THRMHUNT;
+	pci_write_config_byte(fbd_dev, DIMM_THRTCTL, new_ctl);
+
+	pci_write_config_byte(fbd_dev, DIMM_THRTLOW, i7300_idle_thrtlow_saved);
+	pci_write_config_byte(fbd_dev, DIMM_THRTCTL, i7300_idle_thrtctl_saved);
+	pci_read_config_byte(fbd_dev, DIMM_THRTCTL, &got_ctl);
+	WARN_ON_ONCE(got_ctl != i7300_idle_thrtctl_saved);
+}
+
+
+/*
+ * i7300_avg_duration_check()
+ * return 0 if the decaying average of recent idle durations is
+ * more than DURATION_THRESHOLD_US
+ */
+static int i7300_avg_duration_check(void)
+{
+	if (avg_idle_us >= DURATION_THRESHOLD_US)
+		return 0;
+
+#ifdef DEBUG
+	past_skip++;
+#endif
+	return 1;
+}
+
+/* Idle notifier to look at idle CPUs */
+static int i7300_idle_notifier(struct notifier_block *nb, unsigned long val,
+				void *data)
+{
+	unsigned long flags;
+	ktime_t now_ktime;
+	static ktime_t idle_begin_time;
+	static int time_init = 1;
+
+	if (!i7300_idle_thrtlowlm)
+		return 0;
+
+	if (unlikely(time_init)) {
+		time_init = 0;
+		idle_begin_time = ktime_get();
+	}
+
+	spin_lock_irqsave(&i7300_idle_lock, flags);
+	if (val == IDLE_START) {
+
+		cpu_set(smp_processor_id(), idle_cpumask);
+
+		if (cpus_weight(idle_cpumask) != num_online_cpus())
+			goto end;
+
+		now_ktime = ktime_get();
+		idle_begin_time = now_ktime;
+
+		if (i7300_avg_duration_check())
+			goto end;
+
+		i7300_idle_active = 1;
+		total_starts++;
+		start_ktime = now_ktime;
+
+		i7300_idle_start();
+		i7300_idle_ioat_start();
+
+	} else if (val == IDLE_END) {
+		cpu_clear(smp_processor_id(), idle_cpumask);
+		if (cpus_weight(idle_cpumask) == (num_online_cpus() - 1)) {
+			/* First CPU coming out of idle */
+			u64 idle_duration_us;
+
+			now_ktime = ktime_get();
+
+			idle_duration_us = ktime_to_us(ktime_sub
+						(now_ktime, idle_begin_time));
+
+			avg_idle_us =
+				((100 - DURATION_WEIGHT_PCT) * avg_idle_us +
+				 DURATION_WEIGHT_PCT * idle_duration_us) / 100;
+
+			if (i7300_idle_active) {
+				ktime_t idle_ktime;
+
+				idle_ktime = ktime_sub(now_ktime, start_ktime);
+				total_us += ktime_to_us(idle_ktime);
+
+				i7300_idle_ioat_stop();
+				i7300_idle_stop();
+				i7300_idle_active = 0;
+			}
+		}
+	}
+end:
+	spin_unlock_irqrestore(&i7300_idle_lock, flags);
+	return 0;
+}
+
+static struct notifier_block i7300_idle_nb = {
+	.notifier_call = i7300_idle_notifier,
+};
+
+/*
+ * I/O AT controls (PCI bus 0 device 8 function 0)
+ * DIMM controls (PCI bus 0 device 16 function 1)
+ */
+#define IOAT_BUS 0
+#define IOAT_DEVFN PCI_DEVFN(8, 0)
+#define MEMCTL_BUS 0
+#define MEMCTL_DEVFN PCI_DEVFN(16, 1)
+
+struct fbd_ioat {
+	unsigned int vendor;
+	unsigned int ioat_dev;
+};
+
+/*
+ * The i5000 chip-set has the same hooks as the i7300
+ * but support is disabled by default because this driver
+ * has not been validated on that platform.
+ */
+#define SUPPORT_I5000 0
+
+static const struct fbd_ioat fbd_ioat_list[] = {
+	{PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_IOAT_CNB},
+#if SUPPORT_I5000
+	{PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_IOAT},
+#endif
+	{0, 0}
+};
+
+/* table of devices that work with this driver */
+static const struct pci_device_id pci_tbl[] = {
+	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_FBD_CNB) },
+#if SUPPORT_I5000
+	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_5000_ERR) },
+#endif
+	{ } /* Terminating entry */
+};
+
+MODULE_DEVICE_TABLE(pci, pci_tbl);
+
+/* Check for known platforms with I/O-AT */
+static int __init i7300_idle_platform_probe(void)
+{
+	int i;
+
+	fbd_dev = pci_get_bus_and_slot(MEMCTL_BUS, MEMCTL_DEVFN);
+	if (!fbd_dev)
+		return -ENODEV;
+
+	for (i = 0; pci_tbl[i].vendor != 0; i++) {
+		if (fbd_dev->vendor == pci_tbl[i].vendor &&
+		    fbd_dev->device == pci_tbl[i].device) {
+			break;
+		}
+	}
+	if (pci_tbl[i].vendor == 0)
+		return -ENODEV;
+
+	ioat_dev = pci_get_bus_and_slot(IOAT_BUS, IOAT_DEVFN);
+	if (!ioat_dev)
+		return -ENODEV;
+
+	for (i = 0; fbd_ioat_list[i].vendor != 0; i++) {
+		if (ioat_dev->vendor == fbd_ioat_list[i].vendor &&
+		    ioat_dev->device == fbd_ioat_list[i].ioat_dev) {
+			return 0;
+		}
+	}
+	return -ENODEV;
+}
+
+int stats_open_generic(struct inode *inode, struct file *fp)
+{
+	fp->private_data = inode->i_private;
+	return 0;
+}
+
+static ssize_t stats_read_ul(struct file *fp, char __user *ubuf, size_t count,
+				loff_t *off)
+{
+	unsigned long *p = fp->private_data;
+	char buf[32];
+	int len;
+
+	len = snprintf(buf, 32, "%lu\n", *p);
+	return simple_read_from_buffer(ubuf, count, off, buf, len);
+}
+
+static const struct file_operations idle_fops = {
+	.open	= stats_open_generic,
+	.read	= stats_read_ul,
+};
+
+struct debugfs_file_info {
+	void *ptr;
+	char name[32];
+	struct dentry *file;
+} debugfs_file_list[] = {
+				{&total_starts, "total_starts", NULL},
+				{&total_us, "total_us", NULL},
+#ifdef DEBUG
+				{&past_skip, "past_skip", NULL},
+#endif
+				{NULL, "", NULL}
+			};
+
+static int __init i7300_idle_init(void)
+{
+	spin_lock_init(&i7300_idle_lock);
+	cpus_clear(idle_cpumask);
+	total_us = 0;
+
+	if (i7300_idle_platform_probe())
+		return -ENODEV;
+
+	if (i7300_idle_thrt_save())
+		return -ENODEV;
+
+	if (i7300_idle_ioat_init())
+		return -ENODEV;
+
+	debugfs_dir = debugfs_create_dir("i7300_idle", NULL);
+	if (debugfs_dir) {
+		int i = 0;
+
+		while (debugfs_file_list[i].ptr != NULL) {
+			debugfs_file_list[i].file = debugfs_create_file(
+					debugfs_file_list[i].name,
+					S_IRUSR,
+					debugfs_dir,
+					debugfs_file_list[i].ptr,
+					&idle_fops);
+			i++;
+		}
+	}
+
+	idle_notifier_register(&i7300_idle_nb);
+
+	printk(KERN_INFO "i7300_idle: loaded v%s\n", I7300_IDLE_DRIVER_VERSION);
+	return 0;
+}
+
+static void __exit i7300_idle_exit(void)
+{
+	idle_notifier_unregister(&i7300_idle_nb);
+
+	if (debugfs_dir) {
+		int i = 0;
+
+		while (debugfs_file_list[i].file != NULL) {
+			debugfs_remove(debugfs_file_list[i].file);
+			i++;
+		}
+
+		debugfs_remove(debugfs_dir);
+	}
+	i7300_idle_thrt_restore();
+	i7300_idle_ioat_exit();
+}
+
+module_init(i7300_idle_init);
+module_exit(i7300_idle_exit);
+
+MODULE_AUTHOR("Andy Henroid <andrew.d.henroid@intel.com>");
+MODULE_DESCRIPTION("Intel Chipset DIMM Idle Power Saving Driver v"
+			I7300_IDLE_DRIVER_VERSION);
+MODULE_LICENSE("GPL");
diff --git a/include/asm-x86/idle.h b/include/asm-x86/idle.h
index cbb649123612..54ce018d4b6c 100644
--- a/include/asm-x86/idle.h
+++ b/include/asm-x86/idle.h
@@ -6,6 +6,7 @@
 
 struct notifier_block;
 void idle_notifier_register(struct notifier_block *n);
+void idle_notifier_unregister(struct notifier_block *n);
 
 void enter_idle(void);
 void exit_idle(void);
diff --git a/include/linux/pci_ids.h b/include/linux/pci_ids.h
index f1624b396754..efb786d11f2a 100644
--- a/include/linux/pci_ids.h
+++ b/include/linux/pci_ids.h
@@ -2422,6 +2422,7 @@
 #define PCI_DEVICE_ID_INTEL_MCH_PC1	0x359a
 #define PCI_DEVICE_ID_INTEL_E7525_MCH	0x359e
 #define PCI_DEVICE_ID_INTEL_IOAT_CNB	0x360b
+#define PCI_DEVICE_ID_INTEL_FBD_CNB	0x360c
 #define PCI_DEVICE_ID_INTEL_ICH10_0	0x3a14
 #define PCI_DEVICE_ID_INTEL_ICH10_1	0x3a16
 #define PCI_DEVICE_ID_INTEL_ICH10_2	0x3a18