Message-Id: <20070924151320.67f0c332.kristen.c.accardi@intel.com>
Date:	Mon, 24 Sep 2007 15:13:20 -0700
From:	Kristen Carlson Accardi <kristen.c.accardi@...el.com>
To:	jgarzik@...ox.com
Cc:	linux-ide@...r.kernel.org, linux-kernel@...r.kernel.org,
	axboe@...nel.dk, akpm@...ux-foundation.org,
	Kristen Carlson Accardi <kristen.c.accardi@...el.com>
Subject: [patch 1/2] Enable link power management for ata drivers

Device Initiated Power Management, which is defined
in SATA 2.5 can be enabled for disks which support it.
This patch enables DIPM when the user sets the link
power management policy to "min_power".

Additionally, libata drivers can define a function 
(enable_pm) that will perform hardware specific actions to 
enable whatever power management policy the user set up 
for Host Initiated Power management (HIPM).
This power management policy will be activated after all 
disks have been enumerated and intialized.  Drivers should 
also define disable_pm, which will turn off link power 
management, but not change link power management policy.

Signed-off-by:  Kristen Carlson Accardi <kristen.c.accardi@...el.com>
---
 Documentation/scsi/link_power_management_policy.txt |   19 +
 drivers/ata/libata-core.c                           |  194 +++++++++++++++++++-
 drivers/ata/libata-eh.c                             |    5 
 drivers/ata/libata-scsi.c                           |   83 ++++++++
 include/linux/ata.h                                 |    7 
 include/linux/libata.h                              |   25 ++
 6 files changed, 322 insertions(+), 11 deletions(-)

Index: libata-dev/drivers/ata/libata-scsi.c
===================================================================
--- libata-dev.orig/drivers/ata/libata-scsi.c	2007-09-24 13:43:10.000000000 -0700
+++ libata-dev/drivers/ata/libata-scsi.c	2007-09-24 13:46:22.000000000 -0700
@@ -110,6 +110,78 @@ static struct scsi_transport_template at
 };
 
 
+static const struct {
+	enum link_pm	value;
+	char		*name;
+} link_pm_policy[] = {
+	{ NOT_AVAILABLE, "max_performance" },
+	{ MIN_POWER, "min_power" },
+	{ MAX_PERFORMANCE, "max_performance" },
+	{ MEDIUM_POWER, "medium_power" },
+};
+
+const char *ata_scsi_link_pm_policy(enum link_pm policy)
+{
+	int i;
+	char *name = NULL;
+
+	for (i = 0; i < ARRAY_SIZE(link_pm_policy); i++) {
+		if (link_pm_policy[i].value == policy) {
+			name = link_pm_policy[i].name;
+			break;
+		}
+	}
+	return name;
+}
+
+static ssize_t store_link_pm_policy(struct class_device *class_dev,
+	const char *buf, size_t count)
+{
+	struct Scsi_Host *shost = class_to_shost(class_dev);
+	struct ata_port *ap = ata_shost_to_port(shost);
+	enum link_pm policy = 0;
+	int i;
+
+	/*
+ 	 * we are skipping array location 0 on purpose - this
+ 	 * is because a value of NOT_AVAILABLE is displayed
+ 	 * to the user as max_performance, but when the user
+ 	 * writes "max_performance", they actually want the
+ 	 * value to match MAX_PERFORMANCE.
+ 	 */
+	for (i = 1; i < ARRAY_SIZE(link_pm_policy); i++) {
+		const int len = strlen(link_pm_policy[i].name);
+		if (strncmp(link_pm_policy[i].name, buf, len) == 0 &&
+		   buf[len] == '\n') {
+			policy = link_pm_policy[i].value;
+			break;
+		}
+	}
+	if (!policy)
+		return -EINVAL;
+
+	if (ata_scsi_set_link_pm_policy(ap, policy))
+		return -EINVAL;
+	return count;
+}
+
+static ssize_t
+show_link_pm_policy(struct class_device *class_dev, char *buf)
+{
+	struct Scsi_Host *shost = class_to_shost(class_dev);
+	struct ata_port *ap = ata_shost_to_port(shost);
+	const char *policy =
+		ata_scsi_link_pm_policy(ap->pm_policy);
+
+	if (!policy)
+		return -EINVAL;
+
+	return snprintf(buf, 23, "%s\n", policy);
+}
+CLASS_DEVICE_ATTR(link_power_management_policy, S_IRUGO | S_IWUSR,
+		show_link_pm_policy, store_link_pm_policy);
+EXPORT_SYMBOL_GPL(class_device_attr_link_power_management_policy);
+
 static void ata_scsi_invalid_field(struct scsi_cmnd *cmd,
 				   void (*done)(struct scsi_cmnd *))
 {
@@ -3041,6 +3113,17 @@ void ata_scsi_simulate(struct ata_device
 	}
 }
 
+int ata_scsi_set_link_pm_policy(struct ata_port *ap,
+		enum link_pm policy)
+{
+	ap->pm_policy = policy;
+	ap->link.eh_info.action |= ATA_EHI_LPM;
+	ap->link.eh_info.flags |= ATA_EHI_NO_AUTOPSY;
+	ata_port_schedule_eh(ap);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(ata_scsi_set_link_pm_policy);
+
 int ata_scsi_add_hosts(struct ata_host *host, struct scsi_host_template *sht)
 {
 	int i, rc;
Index: libata-dev/include/linux/libata.h
===================================================================
--- libata-dev.orig/include/linux/libata.h	2007-09-24 13:43:10.000000000 -0700
+++ libata-dev/include/linux/libata.h	2007-09-24 13:47:57.000000000 -0700
@@ -140,6 +140,8 @@ enum {
 	ATA_DFLAG_ACPI_PENDING	= (1 << 5), /* ACPI resume action pending */
 	ATA_DFLAG_ACPI_FAILED	= (1 << 6), /* ACPI on devcfg has failed */
 	ATA_DFLAG_AN		= (1 << 7), /* device supports AN */
+	ATA_DFLAG_HIPM		= (1 << 8), /* device supports HIPM */
+	ATA_DFLAG_DIPM		= (1 << 9), /* device supports DIPM */
 	ATA_DFLAG_CFG_MASK	= (1 << 12) - 1,
 
 	ATA_DFLAG_PIO		= (1 << 12), /* device limited to PIO mode */
@@ -181,6 +183,7 @@ enum {
 	ATA_FLAG_NO_IORDY	= (1 << 16), /* controller lacks iordy */
 	ATA_FLAG_ACPI_SATA	= (1 << 17), /* need native SATA ACPI layout */
 	ATA_FLAG_AN		= (1 << 18), /* controller supports AN */
+	ATA_FLAG_IPM		= (1 << 19), /* driver can handle IPM */
 
 	/* The following flag belongs to ap->pflags but is kept in
 	 * ap->flags because it's referenced in many LLDs and will be
@@ -283,6 +286,7 @@ enum {
 	ATA_EHI_RESUME_LINK	= (1 << 1),  /* resume link (reset modifier) */
 	ATA_EHI_NO_AUTOPSY	= (1 << 2),  /* no autopsy */
 	ATA_EHI_QUIET		= (1 << 3),  /* be quiet */
+	ATA_EHI_LPM		= (1 << 4),  /* link power management action */
 
 	ATA_EHI_DID_SOFTRESET	= (1 << 16), /* already soft-reset this port */
 	ATA_EHI_DID_HARDRESET	= (1 << 17), /* already soft-reset this port */
@@ -308,6 +312,7 @@ enum {
 	ATA_HORKAGE_NONCQ	= (1 << 2),	/* Don't use NCQ */
 	ATA_HORKAGE_MAX_SEC_128	= (1 << 3),	/* Limit max sects to 128 */
 	ATA_HORKAGE_BROKEN_HPA	= (1 << 4),	/* Broken HPA */
+	ATA_HORKAGE_IPM		= (1 << 5), 	/* LPM problems */
 };
 
 enum hsm_task_states {
@@ -347,6 +352,18 @@ typedef int (*ata_reset_fn_t)(struct ata
 			      unsigned long deadline);
 typedef void (*ata_postreset_fn_t)(struct ata_link *link, unsigned int *classes);
 
+/*
+ * host pm policy: If you alter this, you also need to alter libata-scsi.c
+ * (for the ascii descriptions)
+ */
+enum link_pm {
+	NOT_AVAILABLE,
+	MIN_POWER,
+	MAX_PERFORMANCE,
+	MEDIUM_POWER,
+};
+extern struct class_device_attribute class_device_attr_link_power_management_policy;
+
 struct ata_ioports {
 	void __iomem		*cmd_addr;
 	void __iomem		*data_addr;
@@ -585,6 +602,7 @@ struct ata_port {
 
 	pm_message_t		pm_mesg;
 	int			*pm_result;
+	enum link_pm		pm_policy;
 
 	struct timer_list	fastdrain_timer;
 	unsigned long		fastdrain_cnt;
@@ -647,7 +665,8 @@ struct ata_port_operations {
 
 	int (*port_suspend) (struct ata_port *ap, pm_message_t mesg);
 	int (*port_resume) (struct ata_port *ap);
-
+	int (*enable_pm) (struct ata_port *ap, enum link_pm policy);
+	int (*disable_pm) (struct ata_port *ap);
 	int (*port_start) (struct ata_port *ap);
 	void (*port_stop) (struct ata_port *ap);
 
@@ -854,7 +873,9 @@ extern int ata_cable_40wire(struct ata_p
 extern int ata_cable_80wire(struct ata_port *ap);
 extern int ata_cable_sata(struct ata_port *ap);
 extern int ata_cable_unknown(struct ata_port *ap);
-
+extern int ata_scsi_set_link_pm_policy(struct ata_port *ap, enum link_pm);
+extern int ata_dev_enable_pm(struct ata_device *dev, enum link_pm policy);
+extern void ata_dev_disable_pm(struct ata_device *dev);
 /*
  * Timing helpers
  */
Index: libata-dev/drivers/ata/libata-core.c
===================================================================
--- libata-dev.orig/drivers/ata/libata-core.c	2007-09-24 13:43:10.000000000 -0700
+++ libata-dev/drivers/ata/libata-core.c	2007-09-24 13:46:22.000000000 -0700
@@ -68,7 +68,8 @@ const unsigned long sata_deb_timing_long
 static unsigned int ata_dev_init_params(struct ata_device *dev,
 					u16 heads, u16 sectors);
 static unsigned int ata_dev_set_xfermode(struct ata_device *dev);
-static unsigned int ata_dev_set_AN(struct ata_device *dev, u8 enable);
+static unsigned int ata_dev_set_feature(struct ata_device *dev,
+					u8 enable, u8 feature);
 static void ata_dev_xfermask(struct ata_device *dev);
 static unsigned long ata_dev_blacklisted(const struct ata_device *dev);
 
@@ -615,6 +616,129 @@ void ata_dev_disable(struct ata_device *
 	}
 }
 
+static int ata_dev_set_dipm(struct ata_device *dev, enum link_pm policy)
+{
+	struct ata_link *link = dev->link;
+	struct ata_port *ap = link->ap;
+	u32 scontrol;
+
+	/*
+	 * disallow DIPM for drivers which haven't set
+	 * ATA_FLAG_IPM.  This is because when DIPM is enabled,
+	 * phy ready will be set in the interrupt status on
+	 * state changes, which will cause some drivers to
+	 * think there are errors - additionally drivers will
+	 * need to disable hot plug.
+	 */
+	if (!(ap->flags & ATA_FLAG_IPM) || !ata_dev_enabled(dev)) {
+		ap->pm_policy = NOT_AVAILABLE;
+		return -EINVAL;
+	}
+
+	/*
+	 * For DIPM, we will only enable it for the
+	 * min_power setting.
+	 *
+	 * Why?  Because Disks are too stupid to know that
+	 * If the host rejects a request to go to SLUMBER
+	 * they should retry at PARTIAL, and instead it
+	 * just would give up.  So, for medium_power to
+	 * work at all, we need to only allow HIPM.
+	 */
+	sata_scr_read(link, SCR_CONTROL, &scontrol);
+
+	switch (policy) {
+	case MIN_POWER:
+		/* no restrictions on IPM transitions */
+		scontrol &= ~(0x3 << 8);
+		sata_scr_write(link, SCR_CONTROL, scontrol);
+
+		/* enable DIPM */
+		if (dev->flags & ATA_DFLAG_DIPM)
+			ata_dev_set_feature(dev, SETFEATURES_SATA_ENABLE,
+						SATA_DIPM);
+		break;
+	case MEDIUM_POWER:
+		/* allow IPM to PARTIAL */
+		scontrol &= ~(0x1 << 8);
+		scontrol |= (0x2 << 8);
+		sata_scr_write(link, SCR_CONTROL, scontrol);
+
+		/* disable DIPM */
+		if (ata_dev_enabled(dev) && (dev->flags & ATA_DFLAG_DIPM))
+			ata_dev_set_feature(dev, SETFEATURES_SATA_DISABLE,
+						SATA_DIPM);
+		break;
+	case NOT_AVAILABLE:
+	case MAX_PERFORMANCE:
+		/* disable all IPM transitions */
+		scontrol |= (0x3 << 8);
+		sata_scr_write(link, SCR_CONTROL, scontrol);
+
+		/* disable DIPM */
+		if (ata_dev_enabled(dev) && (dev->flags & ATA_DFLAG_DIPM))
+			ata_dev_set_feature(dev, SETFEATURES_SATA_DISABLE,
+						SATA_DIPM);
+		break;
+	}
+	return 0;
+}
+
+/**
+ *	ata_dev_enable_pm - enable SATA interface power management
+ *	@device - device to enable ipm for
+ *	@policy - the link power management policy
+ *
+ *	Enable SATA Interface power management.  This will enable
+ *	Device Interface Power Management (DIPM) for min_power
+ * 	policy, and then call driver specific callbacks for
+ *	enabling Host Initiated Power management.
+ *
+ *	Locking: Caller.
+ *	Returns: -EINVAL if IPM is not supported, 0 otherwise.
+ */
+int ata_dev_enable_pm(struct ata_device *dev, enum link_pm policy)
+{
+	int rc = 0;
+	struct ata_port *ap = dev->link->ap;
+
+	/* set HIPM first, then DIPM */
+	if (ap->ops->enable_pm)
+		rc = ap->ops->enable_pm(ap, policy);
+	if (rc)
+		goto enable_pm_out;
+	rc = ata_dev_set_dipm(dev, policy);
+
+enable_pm_out:
+	if (rc)
+		ap->pm_policy = MAX_PERFORMANCE;
+	else
+		ap->pm_policy = policy;
+	return rc;
+}
+
+/**
+ *	ata_dev_disable_pm - disable SATA interface power management
+ *	@device - device to enable ipm for
+ *
+ *	Disable SATA Interface power management.  This will disable
+ *	Device Interface Power Management (DIPM) without changing
+ * 	policy,  call driver specific callbacks for disabling Host
+ * 	Initiated Power management.
+ *
+ *	Locking: Caller.
+ *	Returns: void
+ */
+void ata_dev_disable_pm(struct ata_device *dev)
+{
+	struct ata_port *ap = dev->link->ap;
+
+	ata_dev_set_dipm(dev, MAX_PERFORMANCE);
+	if (ap->ops->disable_pm)
+		ap->ops->disable_pm(ap);
+}
+
+
 /**
  *	ata_devchk - PATA device presence detection
  *	@ap: ATA channel to examine
@@ -2029,7 +2153,8 @@ int ata_dev_configure(struct ata_device 
 		if ((ap->flags & ATA_FLAG_AN) && ata_id_has_AN(id)) {
 			int err;
 			/* issue SET feature command to turn this on */
-			err = ata_dev_set_AN(dev, SETFEATURES_SATA_ENABLE);
+			err = ata_dev_set_feature(dev, SETFEATURES_SATA_ENABLE,
+						SATA_AN);
 			if (err)
 				ata_dev_printk(dev, KERN_ERR,
 						"unable to set AN, err %x\n",
@@ -2057,6 +2182,13 @@ int ata_dev_configure(struct ata_device 
 	if (dev->flags & ATA_DFLAG_LBA48)
 		dev->max_sectors = ATA_MAX_SECTORS_LBA48;
 
+	if (!(dev->horkage & ATA_HORKAGE_IPM)) {
+		if (ata_id_has_hipm(dev->id))
+			dev->flags |= ATA_DFLAG_HIPM;
+		if (ata_id_has_dipm(dev->id))
+			dev->flags |= ATA_DFLAG_DIPM;
+	}
+
 	if (dev->horkage & ATA_HORKAGE_DIAGNOSTIC) {
 		/* Let the user know. We don't want to disallow opens for
 		   rescue purposes, or in case the vendor is just a blithering
@@ -2082,6 +2214,13 @@ int ata_dev_configure(struct ata_device 
 		dev->max_sectors = min_t(unsigned int, ATA_MAX_SECTORS_128,
 					 dev->max_sectors);
 
+	if (ata_dev_blacklisted(dev) & ATA_HORKAGE_IPM) {
+		dev->horkage |= ATA_HORKAGE_IPM;
+
+		/* reset link pm_policy for this port to no pm */
+		ap->pm_policy = MAX_PERFORMANCE;
+	}
+
 	if (ap->ops->dev_config)
 		ap->ops->dev_config(dev);
 
@@ -4048,15 +4187,14 @@ static unsigned int ata_dev_set_xfermode
 	DPRINTK("EXIT, err_mask=%x\n", err_mask);
 	return err_mask;
 }
-
 /**
- *	ata_dev_set_AN - Issue SET FEATURES - SATA FEATURES
+ *	ata_dev_set_feature - Issue SET FEATURES - SATA FEATURES
  *	@dev: Device to which command will be sent
  *	@enable: Whether to enable or disable the feature
+ *	@feature: The sector count represents the feature to set
  *
  *	Issue SET FEATURES - SATA FEATURES command to device @dev
- *	on port @ap with sector count set to indicate Asynchronous
- *	Notification feature
+ *	on port @ap with sector count
  *
  *	LOCKING:
  *	PCI/etc. bus probe sem.
@@ -4064,7 +4202,8 @@ static unsigned int ata_dev_set_xfermode
  *	RETURNS:
  *	0 on success, AC_ERR_* mask otherwise.
  */
-static unsigned int ata_dev_set_AN(struct ata_device *dev, u8 enable)
+static unsigned int ata_dev_set_feature(struct ata_device *dev, u8 enable,
+					u8 feature)
 {
 	struct ata_taskfile tf;
 	unsigned int err_mask;
@@ -4077,7 +4216,7 @@ static unsigned int ata_dev_set_AN(struc
 	tf.feature = enable;
 	tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
 	tf.protocol = ATA_PROT_NODATA;
-	tf.nsect = SATA_AN;
+	tf.nsect = feature;
 
 	err_mask = ata_exec_internal(dev, &tf, NULL, DMA_NONE, NULL, 0);
 
@@ -6031,6 +6170,32 @@ int ata_flush_cache(struct ata_device *d
 	return 0;
 }
 
+static void ata_host_disable_link_pm(struct ata_host *host)
+{
+	int i;
+	struct ata_link *link;
+	struct ata_port *ap;
+	struct ata_device *dev;
+
+	for (i = 0; i < host->n_ports; i++) {
+		ap = host->ports[i];
+		ata_port_for_each_link(link, ap) {
+			ata_link_for_each_dev(dev, link)
+				ata_dev_disable_pm(dev);
+		}
+	}
+}
+
+static void ata_host_enable_link_pm(struct ata_host *host)
+{
+	int i;
+
+	for (i = 0; i < host->n_ports; i++) {
+		struct ata_port *ap = host->ports[i];
+		ata_scsi_set_link_pm_policy(ap, ap->pm_policy);
+	}
+}
+
 #ifdef CONFIG_PM
 static int ata_host_request_pm(struct ata_host *host, pm_message_t mesg,
 			       unsigned int action, unsigned int ehi_flags,
@@ -6101,6 +6266,12 @@ int ata_host_suspend(struct ata_host *ho
 {
 	int rc;
 
+	/*
+ 	 * disable link pm on all ports before requesting
+ 	 * any pm activity
+ 	 */
+	ata_host_disable_link_pm(host);
+
 	rc = ata_host_request_pm(host, mesg, 0, ATA_EHI_QUIET, 1);
 	if (rc == 0)
 		host->dev->power.power_state = mesg;
@@ -6123,6 +6294,9 @@ void ata_host_resume(struct ata_host *ho
 	ata_host_request_pm(host, PMSG_ON, ATA_EH_SOFTRESET,
 			    ATA_EHI_NO_AUTOPSY | ATA_EHI_QUIET, 0);
 	host->dev->power.power_state = PMSG_ON;
+
+	/* reenable link pm */
+	ata_host_enable_link_pm(host);
 }
 #endif
 
@@ -6663,6 +6837,7 @@ int ata_host_register(struct ata_host *h
 		struct ata_port *ap = host->ports[i];
 
 		ata_scsi_scan_host(ap, 1);
+		ata_scsi_set_link_pm_policy(ap, ap->pm_policy);
 	}
 
 	return 0;
@@ -7059,7 +7234,8 @@ const struct ata_port_info ata_dummy_por
  * likely to change as new drivers are added and updated.
  * Do not depend on ABI/API stability.
  */
-
+EXPORT_SYMBOL_GPL(ata_dev_enable_pm);
+EXPORT_SYMBOL_GPL(ata_dev_disable_pm);
 EXPORT_SYMBOL_GPL(sata_deb_timing_normal);
 EXPORT_SYMBOL_GPL(sata_deb_timing_hotplug);
 EXPORT_SYMBOL_GPL(sata_deb_timing_long);
Index: libata-dev/include/linux/ata.h
===================================================================
--- libata-dev.orig/include/linux/ata.h	2007-09-24 13:43:10.000000000 -0700
+++ libata-dev/include/linux/ata.h	2007-09-24 13:46:22.000000000 -0700
@@ -235,6 +235,7 @@ enum {
 
 	/* SETFEATURE Sector counts for SATA features */
 	SATA_AN			= 0x05,  /* Asynchronous Notification */
+	SATA_DIPM		= 0x03,  /* Device Initiated Power Management */
 
 	/* ATAPI stuff */
 	ATAPI_PKT_DMA		= (1 << 0),
@@ -367,6 +368,12 @@ struct ata_taskfile {
 	  ((u64) (id)[(n) + 0]) )
 
 #define ata_id_cdb_intr(id)	(((id)[0] & 0x60) == 0x20)
+#define ata_id_has_hipm(id)	\
+	( (((id)[76] != 0x0000) && ((id)[76] != 0xffff)) && \
+	  ((id)[76] & (1 << 9)) )
+#define ata_id_has_dipm(id)	\
+	( (((id)[76] != 0x0000) && ((id)[76] != 0xffff)) && \
+	  ((id)[78] & (1 << 3)) )
 
 static inline int ata_id_has_fua(const u16 *id)
 {
Index: libata-dev/Documentation/scsi/link_power_management_policy.txt
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ libata-dev/Documentation/scsi/link_power_management_policy.txt	2007-09-24 13:46:22.000000000 -0700
@@ -0,0 +1,19 @@
+This parameter allows the user to set the link (interface) power management.
+There are 3 possible options:
+
+Value			Effect
+----------------------------------------------------------------------------
+min_power		Tell the controller to try to make the link use the
+			least possible power when possible.  This may
+			sacrifice some performance due to increased latency
+			when coming out of lower power states.
+
+max_performance		Generally, this means no power management.  Tell
+			the controller to have performance be a priority
+			over power management.
+
+medium_power		Tell the controller to enter a lower power state
+			when possible, but do not enter the lowest power
+			state, thus improving latency over min_power setting.
+
+
Index: libata-dev/drivers/ata/libata-eh.c
===================================================================
--- libata-dev.orig/drivers/ata/libata-eh.c	2007-09-24 13:43:10.000000000 -0700
+++ libata-dev/drivers/ata/libata-eh.c	2007-09-24 13:46:22.000000000 -0700
@@ -2400,6 +2400,11 @@ static int ata_eh_recover(struct ata_por
 			ehc->i.flags &= ~ATA_EHI_SETMODE;
 		}
 
+		if (ehc->i.action & ATA_EHI_LPM) {
+			ata_link_for_each_dev(dev, link)
+				ata_dev_enable_pm(dev, ap->pm_policy);
+		}
+
 		/* this link is okay now */
 		ehc->i.flags = 0;
 		continue;

-- 
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