OMAP: add PM CONSTRAINTS framework

Implement the wake-up latency constraints using an internal unified function _set_dev_constraint at OMAP PM level, which calls the corresponding function at omap device level.

The actual constraints management code is at the omap device level.

Note: the bus throughput function is implemented but currently is a no-op.

Tested on OMAP3 Beagleboard in RET/OFF using wake-up latency constraints on MPU, CORE and PER.

Signed-off-by Jean Pihet <[email protected]>

---
 arch/arm/plat-omap/omap-pm-constraints.c |  174 ++++++++++++++++--------------
 1 files changed, 91 insertions(+), 83 deletions(-)

arch/arm/plat-omap/omap-pm-constraints.c +11 -11

index c8b4e4c..c6735da 100644
@@ -24,6 +24,7 @@
 /* Interface documentation is in mach/omap-pm.h */
 #include <plat/omap-pm.h>
 #include <plat/omap_device.h>
+#include <plat/common.h>
 
 static bool off_mode_enabled;
 static u32 dummy_context_loss_counter;

@@ -32,119 +33,126 @@ static u32 dummy_context_loss_counter;
  * Device-driver-originated constraints (via board-*.c files)
  */
 
-int omap_pm_set_max_mpu_wakeup_lat(struct device *dev, long t)
+/*
+ * Generic function to omap_device layer for the constraints API.
+ */
+static int _set_dev_constraint(enum omap_pm_constraint_class class,
+			       struct device *req_dev, struct device *dev,
+			       long t)
 {
-	if (!dev || t < -1) {
+	int ret = 0;
+
+	if (!req_dev || !dev || t < -1) {
 		WARN(1, "OMAP PM: %s: invalid parameter(s)", __func__);
 		return -EINVAL;
-	};
-
-	if (t == -1)
-		pr_debug("OMAP PM: remove max MPU wakeup latency constraint: "
-			 "dev %s\n", dev_name(dev));
-	else
-		pr_debug("OMAP PM: add max MPU wakeup latency constraint: "
-			 "dev %s, t = %ld usec\n", dev_name(dev), t);
+	}
 
-	/*

The code at omap device level manages the constraints: storage, tracking of requesters and dispatching to the low level code (e.g. powerdomain for the wake-up latency constraints).

Tested on OMAP3 Beagleboard in RET/OFF using wake-up latency constraints on MPU, CORE and PER.

Signed-off-by Jean Pihet <[email protected]>

---
 arch/arm/plat-omap/include/plat/omap_device.h |   14 ++
 arch/arm/plat-omap/omap_device.c              |  202 +++++++++++++++++++++++++
 2 files changed, 216 insertions(+), 0 deletions(-)

arch/arm/plat-omap/include/plat/omap_device.h +2 -0

index e4c349f..d4766c4 100644
@@ -32,9 +32,11 @@
 #define __ARCH_ARM_PLAT_OMAP_INCLUDE_MACH_OMAP_DEVICE_H
 
 #include <linux/kernel.h>
+#include <linux/plist.h>
 #include <linux/platform_device.h>
 
 #include <plat/omap_hwmod.h>
+#include <plat/omap-pm.h>
 
 extern struct device omap_device_parent;
 

@@ -73,6 +75,15 @@ struct omap_device {
 	s8				pm_lat_level;

arch/arm/plat-omap/include/plat/omap_device.h +4 -0

+	struct plist_node		node;
 };
 
 /* Device driver interface (call via platform_data fn ptrs) */

@@ -107,6 +118,9 @@ void __iomem *omap_device_get_rt_va(struct omap_device *od);
 int omap_device_align_pm_lat(struct platform_device *pdev,
 			     u32 new_wakeup_lat_limit);
 struct powerdomain *omap_device_get_pwrdm(struct omap_device *od);
+int omap_device_set_dev_constraint(enum omap_pm_constraint_class class,
+				   struct device *req_dev,
+				   struct device *dev, long t);
 u32 omap_device_get_context_loss_count(struct platform_device *pdev);
 
 /* Other */

arch/arm/plat-omap/omap_device.c +30 -0

index 9bbda9a..9199d3e 100644
@@ -292,10 +292,205 @@ static void _add_optional_clock_clkdev(struct omap_device *od,
 	}
 }
 
+/* plist that stores the devices wake-up latency constraints */
+static struct plist_head _wkup_lat_constraints_list;
+/* Spinlock that protects the constraints lists */
+static spinlock_t _constraints_lock;
+/* Mutex that protects the constraints lists ops */
+static struct mutex _constraints_mutex;
+
+/*
+ * _store_constraint: add/update/remove a constraint from a plist
+ *
+ * @constraints_list: plist to use
+ * @req_dev: constraint requester, used to track the requests
+ * @target: target which the constraint applies to (e.g. power domain ID or
+ *  ptr for wake-up latency constraints)
+ * @value: constraint value. The plist is sorted by the value. -1 remove the
+ *  constraint from the list
+ * @ascending: return the lowest constraint value if set to 1, return the
+ *  highest value if not.
+ *
+ * Returns the strongest constraint value for the given target, 0 in the
+ * case there is no constraint on the given target or a negative value in
+ * case of error.
+ * The caller must check the validity of the parameters.
+ */
+static long _store_constraint(struct plist_head *constraints_list,
+			      struct device *req_dev, void *target,
+			      long value, int ascending)
+{
+	struct omap_device_constraints_entry *user;
+	int found = 0, ret = 0;

arch/arm/plat-omap/omap_device.c +51 -0

+	if (value >= 0) {
+		/* Add new entry to the list or update existing request */
+		if (found &&
+		    user->constraint_value == value &&
+		    user->target == target) {
+			goto exit_ok;
+		} else if (!found) {
+			user = kzalloc(
+				sizeof(struct omap_device_constraints_entry),
+				GFP_KERNEL);
+			if (!user) {
+				pr_err("%s: FATAL ERROR: kzalloc failed\n",
+				       __func__);
+				ret = -ENOMEM;
+				goto exit_error;
+			}
+			user->req_dev = req_dev;
+		} else {
+			plist_del(&user->node, constraints_list);
+		}
+
+		plist_node_init(&user->node, value);
+		plist_add(&user->node, constraints_list);
+		user->node.prio = user->constraint_value = value;
+		user->target = target;
+	} else {
+		/* Remove the constraint from the list */
+		if (!found) {
+			pr_err("%s: Error: no prior constraint to release\n",
+			       __func__);
+			ret = -EINVAL;
+			goto exit_error;
+		}
+
+		plist_del(&user->node, constraints_list);
+		kfree(user);
+	}
+
+exit_ok:
+	/* Find the strongest constraint for the given target */
+	ret = 0;
+	if (ascending) {
+		list_for_each_entry(user, &(constraints_list)->node_list,
+				    node.plist.node_list) {
+			/* Find the lowest (i.e. first) value for the target */
+			if (user->target == target) {
+				ret = user->constraint_value;
+				break;
+			}
+		}
+	} else {

arch/arm/plat-omap/omap_device.c +25 -0

+exit_error:
+	mutex_unlock(&_constraints_mutex);
+
+	return ret;
+}
 
 /* Public functions for use by core code */
 
 /**
+ * omap_device_set_dev_constraint - set/release a device constraint
+ * @class: constraint class
+ * @req_dev: constraint requester, used for tracking the constraints
+ * @dev: device to apply the constraint to. Must have an associated omap_device
+ * @t: constraint value. A value of -1 removes the constraint.
+ *
+ * Using the primary hwmod, set/release a device constraint for the dev
+ * device, requested by the req_dev device. Depending of the constraint class
+ * this code calls the appropriate low level code, e.g. power domain for
+ * the wake-up latency constraints.
+ *
+ * If any hwmods exist for the omap_device assoiated with @dev,
+ * set/release the constraint for the corresponding hwmods, otherwise return
+ * -EINVAL.
+ */
+int omap_device_set_dev_constraint(enum omap_pm_constraint_class class,
+				   struct device *req_dev,
+				   struct device *dev, long t)
+{
+	struct omap_device *od;

arch/arm/plat-omap/omap_device.c +9 -0

+		pr_err("%s: Error: platform device for device %s not valid\n",
+		       __func__, dev_name(dev));
+		return -EINVAL;
+	}
+
+	/* Find the associated omap_device for dev */
+	od = _find_by_pdev(pdev);
+	if (!(od->hwmods_cnt)) {
+		pr_err("%s: Error: No hwmod for device %s\n",

arch/arm/plat-omap/omap_device.c +8 -0

+		pwrdm = omap_device_get_pwrdm(od);
+		if (!pwrdm) {
+			pr_err("%s: Error: No pwrdm for device %s\n",
+			       __func__, dev_name(dev));
+			ret = -EINVAL;
+			break;
+		}
+

arch/arm/plat-omap/omap_device.c +20 -0

+		} else {
+			pr_err("%s: Error storing the constraint for device "
+			       "%s\n", __func__, dev_name(dev));
+		}
+
+		break;
+	case OMAP_PM_CONSTRAINT_THROUGHPUT:
+		WARN(1, "OMAP PM: %s: Bus throughput constraint class \
+		     not implemented\n", __func__);
+		ret = -EINVAL;
+		break;
+	default:
+		WARN(1, "OMAP PM: %s: invalid constraint class %d",
+		     __func__, class);
+	}
+
+	return ret;
+}
+
+/**
  * omap_device_get_context_loss_count - get lost context count
  * @od: struct omap_device *
  *

@@ -824,6 +1019,13 @@ struct device omap_device_parent = {
 
 static int __init omap_device_init(void)
 {

Quoted 8 lines · Jean Pihet

The code at omap device level manages the constraints: storage, tracking of requesters and dispatching to the low level code (e.g. powerdomain for the wake-up latency constraints).

Tested on OMAP3 Beagleboard in RET/OFF using wake-up latency constraints on MPU, CORE and PER.

Signed-off-by Jean Pihet <[email protected]>

Subject prefix should be: OMAP2+: omap_device: ...

Quoted 23 lines

---
?arch/arm/plat-omap/include/plat/omap_device.h | ? 14 ++ ?arch/arm/plat-omap/omap_device.c ? ? ? ? ? ? ?| ?202 +++++++++++++++++++++++++ ?2 files changed, 216 insertions(+), 0 deletions(-)

arch/arm/plat-omap/include/plat/omap_device.h +0 -0

index e4c349f..d4766c4 100644
@@ -32,9 +32,11 @@

?#define __ARCH_ARM_PLAT_OMAP_INCLUDE_MACH_OMAP_DEVICE_H

?#include <linux/kernel.h>
+#include <linux/plist.h>
?#include <linux/platform_device.h>

?#include <plat/omap_hwmod.h>
+#include <plat/omap-pm.h>

?extern struct device omap_device_parent;

arch/arm/plat-omap/include/plat/omap_device.h +0 -0

@@ -73,6 +75,15 @@ struct omap_device {
 ? ? ? s8 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?pm_lat_level;

arch/arm/plat-omap/include/plat/omap_device.h struct omap_device { · line 85

Quoted 10 lines

arch/arm/plat-omap/include/plat/omap_device.h +8 -0

 ? ? ? u8 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?hwmods_cnt;
 ? ? ? u8 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?_state;
+
+};
+
+/* Linked list for the devices constraints entries */
+struct omap_device_constraints_entry {
+ ? ? struct device ? ? ? ? ? ? ? ? ? *req_dev;
+ ? ? void ? ? ? ? ? ? ? ? ? ? ? ? ? ?*target;
+ ? ? unsigned long ? ? ? ? ? ? ? ? ? constraint_value;

constratint_ prefix not needed

Also, should this be 'long' (instead of unsigned long' to match the value from the API below?

Quoted 57 lines

arch/arm/plat-omap/include/plat/omap_device.h +1 -0

+ ? ? struct plist_node ? ? ? ? ? ? ? node;
 ?};
 

?/* Device driver interface (call via platform_data fn ptrs) */

arch/arm/plat-omap/include/plat/omap_device.h +3 -0

@@ -107,6 +118,9 @@ void __iomem *omap_device_get_rt_va(struct omap_device *od);
 ?int omap_device_align_pm_lat(struct platform_device *pdev,
 ? ? ? ? ? ? ? ? ? ? ? ? ? ?u32 new_wakeup_lat_limit);
 ?struct powerdomain *omap_device_get_pwrdm(struct omap_device *od);
+int omap_device_set_dev_constraint(enum omap_pm_constraint_class class,
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?struct device *req_dev,
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?struct device *dev, long t);
 ?u32 omap_device_get_context_loss_count(struct platform_device *pdev);
 

?/* Other */

arch/arm/plat-omap/omap_device.c +35 -0

index 9bbda9a..9199d3e 100644
@@ -292,10 +292,205 @@ static void _add_optional_clock_clkdev(struct omap_device *od,
 ? ? ? }
 ?}
 
+/* plist that stores the devices wake-up latency constraints */
+static struct plist_head _wkup_lat_constraints_list;
+/* Spinlock that protects the constraints lists */
+static spinlock_t _constraints_lock;
+/* Mutex that protects the constraints lists ops */
+static struct mutex _constraints_mutex;
+
+/*
+ * _store_constraint: add/update/remove a constraint from a plist
+ *
+ * @constraints_list: plist to use
+ * @req_dev: constraint requester, used to track the requests
+ * @target: target which the constraint applies to (e.g. power domain ID or
+ * ?ptr for wake-up latency constraints)
+ * @value: constraint value. The plist is sorted by the value. -1 remove the
+ * ?constraint from the list
+ * @ascending: return the lowest constraint value if set to 1, return the
+ * ?highest value if not.
+ *
+ * Returns the strongest constraint value for the given target, 0 in the
+ * case there is no constraint on the given target or a negative value in
+ * case of error.
+ * The caller must check the validity of the parameters.
+ */
+static long _store_constraint(struct plist_head *constraints_list,
+ ? ? ? ? ? ? ? ? ? ? ? ? ? struct device *req_dev, void *target,
+ ? ? ? ? ? ? ? ? ? ? ? ? ? long value, int ascending)
+{
+ ? ? struct omap_device_constraints_entry *user;
+ ? ? int found = 0, ret = 0;
+
+ ? ? mutex_lock(&_constraints_mutex);
+
+ ? ? /* Check if the constraint requester is already in the list */
+ ? ? plist_for_each_entry(user, constraints_list, node) {

arch/arm/plat-omap/omap_device.c static void _add_optional_clock_clkdev(struct omap_device *od, · line 334

Quoted 5 lines

arch/arm/plat-omap/omap_device.c +5 -0

+ ? ? ? ? ? ? if (user->req_dev == req_dev) {
+ ? ? ? ? ? ? ? ? ? ? found = 1;
+ ? ? ? ? ? ? ? ? ? ? break;
+ ? ? ? ? ? ? }
+ ? ? }

You should probably release the mutex here so it's not held over the kzalloc (which can sleep.)

Minor: I'm not a fan of this common 'found = 1' technique. ?Rather, use a temporary list iterator, e.g:

? ? ? ?struct omap_device_constraints_entry *user = NULL, *tmp_user;

? ? ? ?plist_for_each_entry(tmp_user, constraints_list, node) { ? ? ? ? ? ? ? ?if (user->req_dev == req_dev) {
? ? ? ? ? ? ? ? ? ? ? ?user = tmp_user;
? ? ? ? ? ? ? ? ? ? ? ?break;
? ? ? ? ? ? ? ?}
? ? ? ?}

Then, rather than checking 'found' below, check 'user'.

Quoted 56 lines

arch/arm/plat-omap/omap_device.c +55 -0

+ ? ? if (value >= 0) {
+ ? ? ? ? ? ? /* Add new entry to the list or update existing request */
+ ? ? ? ? ? ? if (found &&
+ ? ? ? ? ? ? ? ? user->constraint_value == value &&
+ ? ? ? ? ? ? ? ? user->target == target) {
+ ? ? ? ? ? ? ? ? ? ? goto exit_ok;
+ ? ? ? ? ? ? } else if (!found) {
+ ? ? ? ? ? ? ? ? ? ? user = kzalloc(
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? sizeof(struct omap_device_constraints_entry),
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? GFP_KERNEL);
+ ? ? ? ? ? ? ? ? ? ? if (!user) {
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? pr_err("%s: FATAL ERROR: kzalloc failed\n",
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?__func__);
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ret = -ENOMEM;
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? goto exit_error;
+ ? ? ? ? ? ? ? ? ? ? }
+ ? ? ? ? ? ? ? ? ? ? user->req_dev = req_dev;
+ ? ? ? ? ? ? } else {
+ ? ? ? ? ? ? ? ? ? ? plist_del(&user->node, constraints_list);
+ ? ? ? ? ? ? }
+
+ ? ? ? ? ? ? plist_node_init(&user->node, value);
+ ? ? ? ? ? ? plist_add(&user->node, constraints_list);
+ ? ? ? ? ? ? user->node.prio = user->constraint_value = value;
+ ? ? ? ? ? ? user->target = target;
+ ? ? } else {
+ ? ? ? ? ? ? /* Remove the constraint from the list */
+ ? ? ? ? ? ? if (!found) {
+ ? ? ? ? ? ? ? ? ? ? pr_err("%s: Error: no prior constraint to release\n",
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ?__func__);
+ ? ? ? ? ? ? ? ? ? ? ret = -EINVAL;
+ ? ? ? ? ? ? ? ? ? ? goto exit_error;
+ ? ? ? ? ? ? }
+
+ ? ? ? ? ? ? plist_del(&user->node, constraints_list);
+ ? ? ? ? ? ? kfree(user);
+ ? ? }
+
+exit_ok:
+ ? ? /* Find the strongest constraint for the given target */
+ ? ? ret = 0;
+ ? ? if (ascending) {
+ ? ? ? ? ? ? list_for_each_entry(user, &(constraints_list)->node_list,
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? node.plist.node_list) {
+ ? ? ? ? ? ? ? ? ? ? /* Find the lowest (i.e. first) value for the target */
+ ? ? ? ? ? ? ? ? ? ? if (user->target == target) {
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ret = user->constraint_value;
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? break;
+ ? ? ? ? ? ? ? ? ? ? }
+ ? ? ? ? ? ? }
+ ? ? } else {
+ ? ? ? ? ? ? list_for_each_entry_reverse(user,
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? &(constraints_list)->node_list,
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? node.plist.node_list) {
+ ? ? ? ? ? ? ? ? ? ? /* Find the highest (i.e. last) value for the target */

arch/arm/plat-omap/omap_device.c static void _add_optional_clock_clkdev(struct omap_device *od, · line 395

Quoted 6 lines

arch/arm/plat-omap/omap_device.c +6 -0

+ ? ? ? ? ? ? ? ? ? ? if (user->target == target) {
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ret = user->constraint_value;
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? break;
+ ? ? ? ? ? ? ? ? ? ? }
+ ? ? ? ? ? ? }
+ ? ? }

Hmm, why can't you use plist_first() and plist_last() here?

Quoted 34 lines

arch/arm/plat-omap/omap_device.c +5 -0

+exit_error:
+ ? ? mutex_unlock(&_constraints_mutex);
+
+ ? ? return ret;
+}
 

?/* Public functions for use by core code */

?/**
+ * omap_device_set_dev_constraint - set/release a device constraint
+ * @class: constraint class
+ * @req_dev: constraint requester, used for tracking the constraints
+ * @dev: device to apply the constraint to. Must have an associated omap_device
+ * @t: constraint value. A value of -1 removes the constraint.
+ *
+ * Using the primary hwmod, set/release a device constraint for the dev
+ * device, requested by the req_dev device. Depending of the constraint class
+ * this code calls the appropriate low level code, e.g. power domain for
+ * the wake-up latency constraints.
+ *
+ * If any hwmods exist for the omap_device assoiated with @dev,
+ * set/release the constraint for the corresponding hwmods, otherwise return
+ * -EINVAL.
+ */

arch/arm/plat-omap/omap_device.c +9 -0

+int omap_device_set_dev_constraint(enum omap_pm_constraint_class class,
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?struct device *req_dev,
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?struct device *dev, long t)
+{
+ ? ? struct omap_device *od;
+ ? ? struct omap_hwmod *oh;
+ ? ? struct platform_device *pdev;
+ ? ? struct powerdomain *pwrdm = NULL;
+ ? ? u32 ret = -EINVAL;

arch/arm/plat-omap/omap_device.c

Quoted 6 lines

arch/arm/plat-omap/omap_device.c +6 -0

+
+ ? ? /* Look for the platform device for dev */
+ ? ? pdev = to_platform_device(dev);
+
+ ? ? /* Try to catch non platform devices. */
+ ? ? if (pdev->name == NULL) {

This should check for a valid omap_device, not platform_device.

Quoted 13 lines

+ ? ? ? ? ? ? pr_err("%s: Error: platform device for device %s not valid\n",
+ ? ? ? ? ? ? ? ? ? ?__func__, dev_name(dev));
+ ? ? ? ? ? ? return -EINVAL;
+ ? ? }
+
+ ? ? /* Find the associated omap_device for dev */
+ ? ? od = _find_by_pdev(pdev);
+ ? ? if (!(od->hwmods_cnt)) {
+ ? ? ? ? ? ? pr_err("%s: Error: No hwmod for device %s\n",
+ ? ? ? ? ? ? ? ? ? ?__func__, dev_name(dev));
+ ? ? ? ? ? ? return -EINVAL;
+ ? ? }

arch/arm/plat-omap/omap_device.c

Quoted 7 lines

arch/arm/plat-omap/omap_device.c +7 -0

+
+ ? ? /* Find the associated omap_hwmod for dev */
+ ? ? oh = od->hwmods[0];
+
+ ? ? switch (class) {
+ ? ? case OMAP_PM_CONSTRAINT_WKUP_LAT:
+ ? ? ? ? ? ? /* Find the pwrdm associated to dev */

comment doesn't add anything to code

Quoted 8 lines

+ ? ? ? ? ? ? pwrdm = omap_device_get_pwrdm(od);
+ ? ? ? ? ? ? if (!pwrdm) {
+ ? ? ? ? ? ? ? ? ? ? pr_err("%s: Error: No pwrdm for device %s\n",
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ?__func__, dev_name(dev));
+ ? ? ? ? ? ? ? ? ? ? ret = -EINVAL;
+ ? ? ? ? ? ? ? ? ? ? break;
+ ? ? ? ? ? ? }

arch/arm/plat-omap/omap_device.c +1 -0

+

arch/arm/plat-omap/omap_device.c

Quoted 10 lines

arch/arm/plat-omap/omap_device.c +10 -0

+ ? ? ? ? ? ? /*
+ ? ? ? ? ? ? ?* Store the constraint in the appropriate list and find the
+ ? ? ? ? ? ? ?* strongest constraint for the given pwrdm
+ ? ? ? ? ? ? ?*/
+ ? ? ? ? ? ? ret = _store_constraint(&_wkup_lat_constraints_list,
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? req_dev, (void *) pwrdm, t, 1);
+
+ ? ? ? ? ? ? /* Apply the constraint to the corresponding pwrdm */
+ ? ? ? ? ? ? if (ret >= 0) {
+ ? ? ? ? ? ? ? ? ? ? ret = omap_hwmod_update_power_state(oh, ret);

This function doesn't exist yet, so the series up to here will not compile.

Quoted 25 lines

+ ? ? ? ? ? ? } else {
+ ? ? ? ? ? ? ? ? ? ? pr_err("%s: Error storing the constraint for device "
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ?"%s\n", __func__, dev_name(dev));
+ ? ? ? ? ? ? }

arch/arm/plat-omap/omap_device.c +16 -0

+
+ ? ? ? ? ? ? break;
+ ? ? case OMAP_PM_CONSTRAINT_THROUGHPUT:
+ ? ? ? ? ? ? WARN(1, "OMAP PM: %s: Bus throughput constraint class \
+ ? ? ? ? ? ? ? ? ?not implemented\n", __func__);
+ ? ? ? ? ? ? ret = -EINVAL;
+ ? ? ? ? ? ? break;
+ ? ? default:
+ ? ? ? ? ? ? WARN(1, "OMAP PM: %s: invalid constraint class %d",
+ ? ? ? ? ? ? ? ? ?__func__, class);
+ ? ? }
+
+ ? ? return ret;
+}
+
+/**

? * omap_device_get_context_loss_count - get lost context count ? * @od: struct omap_device *
? *

arch/arm/plat-omap/omap_device.c +0 -0

@@ -824,6 +1019,13 @@ struct device omap_device_parent = {
 

arch/arm/plat-omap/omap_device.c struct device omap_device_parent = { · line 1031

Quoted 12 lines

arch/arm/plat-omap/omap_device.c +7 -0

 ?static int __init omap_device_init(void)
 ?{
+ ? ? /* Initialize priority ordered list for wakeup latency constraint */
+ ? ? spin_lock_init(&_constraints_lock);
+ ? ? plist_head_init(&_wkup_lat_constraints_list, &_constraints_lock);
+
+ ? ? /* res_mutex protects res_list add and del ops */
+ ? ? mutex_init(&_constraints_mutex);
+
 ? ? ? return device_register(&omap_device_parent);
 ?}
 ?core_initcall(omap_device_init);

Kevin

Quoted 24 lines

Quoted 23 lines

+exit_ok:
+ ? ? /* Find the strongest constraint for the given target */
+ ? ? ret = 0;
+ ? ? if (ascending) {
+ ? ? ? ? ? ? list_for_each_entry(user, &(constraints_list)->node_list,
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? node.plist.node_list) {
+ ? ? ? ? ? ? ? ? ? ? /* Find the lowest (i.e. first) value for the target */
+ ? ? ? ? ? ? ? ? ? ? if (user->target == target) {
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ret = user->constraint_value;
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? break;
+ ? ? ? ? ? ? ? ? ? ? }
+ ? ? ? ? ? ? }
+ ? ? } else {
+ ? ? ? ? ? ? list_for_each_entry_reverse(user,
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? &(constraints_list)->node_list,
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? node.plist.node_list) {
+ ? ? ? ? ? ? ? ? ? ? /* Find the highest (i.e. last) value for the target */
+ ? ? ? ? ? ? ? ? ? ? if (user->target == target) {
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ret = user->constraint_value;
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? break;
+ ? ? ? ? ? ? ? ? ? ? }
+ ? ? ? ? ? ? }
+ ? ? }

Quoted 1 line

Hmm, why can't you use plist_first() and plist_last() here?

Because the plist is sorted by the 'prio' field (which is 'value' in this code) and this function searches for the strongest constraint for a given target. So it is needed to iterate through the list in order to find the first (or last) constraint with the right target.

Quoted 34 lines

Quoted 34 lines

arch/arm/plat-omap/omap_device.c +5 -0

+exit_error:
+ ? ? mutex_unlock(&_constraints_mutex);
+
+ ? ? return ret;
+}

?/* Public functions for use by core code */

?/**
+ * omap_device_set_dev_constraint - set/release a device constraint
+ * @class: constraint class
+ * @req_dev: constraint requester, used for tracking the constraints
+ * @dev: device to apply the constraint to. Must have an associated omap_device
+ * @t: constraint value. A value of -1 removes the constraint.
+ *
+ * Using the primary hwmod, set/release a device constraint for the dev
+ * device, requested by the req_dev device. Depending of the constraint class
+ * this code calls the appropriate low level code, e.g. power domain for
+ * the wake-up latency constraints.
+ *
+ * If any hwmods exist for the omap_device assoiated with @dev,
+ * set/release the constraint for the corresponding hwmods, otherwise return
+ * -EINVAL.
+ */

(quoted diff) +9 -0

+int omap_device_set_dev_constraint(enum omap_pm_constraint_class class,
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?struct device *req_dev,
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?struct device *dev, long t)
+{
+ ? ? struct omap_device *od;
+ ? ? struct omap_hwmod *oh;
+ ? ? struct platform_device *pdev;
+ ? ? struct powerdomain *pwrdm = NULL;
+ ? ? u32 ret = -EINVAL;

Quoted 8 lines

Review

Quoted 6 lines

(quoted diff) +6 -0

+
+ ? ? /* Look for the platform device for dev */
+ ? ? pdev = to_platform_device(dev);
+
+ ? ? /* Try to catch non platform devices. */
+ ? ? if (pdev->name == NULL) {

This should check for a valid omap_device, not platform_device.

This check remains but the check below is changed, see below.

Hwmod is queried from the omap device layer to change the power domains next power state. Hwmod retrieves the correct power domain and if it exists it calls the corresponding power domain function.

Tested on OMAP3 Beagleboard in RET/OFF using wake-up latency constraints on MPU, CORE and PER.

Signed-off-by Jean Pihet <[email protected]>

---
 arch/arm/mach-omap2/omap_hwmod.c             |   29 +++++++++++++++++++++++++-
 arch/arm/plat-omap/include/plat/omap_hwmod.h |    1 +
 2 files changed, 29 insertions(+), 1 deletions(-)

arch/arm/mach-omap2/omap_hwmod.c +1 -0

index cf8cc9b..8caf2c5 100644
@@ -142,6 +142,7 @@
 #include "powerdomain.h"
 #include <plat/clock.h>
 #include <plat/omap_hwmod.h>
+#include <plat/omap_device.h>
 #include <plat/prcm.h>
 
 #include "cm2xxx_3xxx.h"

arch/arm/mach-omap2/omap_hwmod.c +3 -1

+}
+
 /**
  * omap_hwmod_get_context_loss_count - get lost context count
  * @oh: struct omap_hwmod *
  *
- * Query the powerdomain of of @oh to get the context loss
+ * Query the powerdomain of @oh to get the context loss
  * count for this device.
  *
  * Returns the context loss count of the powerdomain assocated with @oh

arch/arm/plat-omap/include/plat/omap_hwmod.h +0 -0

index 65bcad4..f27110e 100644

When a wake-up constraint is requested or removed the omap device layer dispatches the updated strongest constraint value.
The power domains get the next power state programmed directly in the registers via pwrdm_wakeuplat_update_pwrst.

Note about PM QOS: the MPU and CORE power domains get the next power state via cpuidle, which get the strongest wake-up latency constraint by querying PM QOS. The usage of PM QOS is temporary, until a generic solution is in place.

Tested on OMAP3 Beagleboard in RET/OFF using wake-up latency constraints on MPU, CORE and PER.

Signed-off-by Jean Pihet <[email protected]>

---
 arch/arm/mach-omap2/powerdomain.c |  100 +++++++++++++++++++++++++++++++++++++
 arch/arm/mach-omap2/powerdomain.h |   24 ++++++++-
 2 files changed, 122 insertions(+), 2 deletions(-)

arch/arm/mach-omap2/powerdomain.c +8 -0

index eaed0df..54ac955 100644
@@ -19,6 +19,7 @@
 #include <linux/list.h>
 #include <linux/errno.h>
 #include <linux/string.h>
+
 #include "cm2xxx_3xxx.h"
 #include "prcm44xx.h"
 #include "cm44xx.h"

@@ -176,6 +177,105 @@ static int _pwrdm_post_transition_cb(struct powerdomain *pwrdm, void *unused)
 	return 0;
 }
 
+/*
+ * Test if the current powerdomain is MPU or CORE
+ *
+ * This function is only used by pwrdm_wakeuplat_update_pwrst
+ * which applies the MPU and CORE power domains constraints using PM QOS.
+ *
+ * This will disappear when all power domains will be controlled directly

arch/arm/mach-omap2/powerdomain.c +81 -0

+/**
+ * pwrdm_wakeuplat_update_pwrst - Update power domain power state if needed
+ * @pwrdm: struct powerdomain * to which requesting device belongs to.
+ * @min_latency: the allowed wake-up latency for the given power domain. A
+ *  value of 0 means 'no constraint' on the pwrdm.
+ *
+ * Finds the power domain next power state that fulfills the constraint.
+ * Programs a new target state if it is different from current power state.
+ *
+ * Returns 0 upon success.
+ */
+int pwrdm_wakeuplat_update_pwrst(struct powerdomain *pwrdm, long min_latency)
+{
+	int ret = 0, new_state = 0;
+
+	if (!pwrdm) {
+		WARN(1, "powerdomain: %s: invalid parameter(s)", __func__);
+		return -EINVAL;
+	}
+
+	/*
+	 * Apply constraints to MPU and CORE via the PM QOS API.
+	 * Every power domain struct has a pm_qos_request_list field
+	 */
+	if (is_pwrdm_mpu_or_core(pwrdm)) {
+		if (pm_qos_request_active(&(pwrdm->pm_qos_request)))
+			pm_qos_remove_request(&(pwrdm->pm_qos_request));
+
+		if (min_latency > 0)
+			pm_qos_add_request(&(pwrdm->pm_qos_request),
+					   PM_QOS_CPU_DMA_LATENCY,
+					   min_latency);
+
+		return 0;
+	}
+
+	/*
+	 * Apply constraints to pwrdm other than MPU and CORE by programming
+	 * the pwrdm next power state.
+	 */
+
+	/* Find power state with wakeup latency < minimum constraint */
+	for (new_state = 0x0; new_state < PWRDM_MAX_PWRSTS; new_state++) {
+		if (min_latency == 0 ||
+		    pwrdm->wakeup_lat[new_state] <= min_latency)
+			break;
+	}
+
+	switch (new_state) {
+	case PWRDM_FUNC_PWRST_OFF:
+		new_state = PWRDM_POWER_OFF;
+		break;
+	case PWRDM_FUNC_PWRST_OSWR:
+		pwrdm_set_logic_retst(pwrdm, PWRDM_POWER_OFF);
+		new_state = PWRDM_POWER_RET;
+		break;
+	case PWRDM_FUNC_PWRST_CSWR:
+		pwrdm_set_logic_retst(pwrdm, PWRDM_POWER_RET);
+		new_state = PWRDM_POWER_RET;
+		break;
+	case PWRDM_FUNC_PWRST_ON:
+		new_state = PWRDM_POWER_ON;
+		break;
+	default:
+		pr_warn("powerdomain: requested latency constraint not "
+			"supported %s set to ON state\n", pwrdm->name);
+		new_state = PWRDM_POWER_ON;
+		break;
+	}
+
+	if (pwrdm_read_pwrst(pwrdm) != new_state)
+		ret = omap_set_pwrdm_state(pwrdm, new_state);
+
+	pr_debug("powerdomain: %s pwrst: curr=%d, prev=%d next=%d "
+		 "min_latency=%ld, set_state=%d\n", pwrdm->name,
+		 pwrdm_read_pwrst(pwrdm), pwrdm_read_prev_pwrst(pwrdm),
+		 pwrdm_read_next_pwrst(pwrdm), min_latency, new_state);
+
+	return ret;
+}
+
 /* Public functions */
 
 /**

arch/arm/mach-omap2/powerdomain.h +4 -1

index 0b7a357..23b3408 100644
@@ -19,7 +19,10 @@
 
 #include <linux/types.h>
 #include <linux/list.h>
-
+#include <linux/plist.h>
+#include <linux/mutex.h>
+#include <linux/spinlock.h>
+#include <linux/pm_qos_params.h>
 #include <linux/atomic.h>
 
 #include <plat/cpu.h>

@@ -46,6 +49,15 @@
 
 #define PWRSTS_OFF_RET_ON	(PWRSTS_OFF_RET | (1 << PWRDM_POWER_ON))

arch/arm/mach-omap2/powerdomain.h +7 -1

 /* Powerdomain flags */
 #define PWRDM_HAS_HDWR_SAR	(1 << 0) /* hardware save-and-restore support */

@@ -96,7 +108,11 @@ struct powerdomain;
  * @state_counter:
  * @timer:
  * @state_timer:
- *
+ * @wakeup_lat: wakeup latencies (in us) for possible powerdomain power states
+ * Note about the wakeup latencies ordering: the values must be sorted
+ *  in decremental order
+ * @pm_qos_request: PM QOS handle, only used to control the MPU and CORE power
+ *  domains states; to be removed when a generic solution is in place.
  * @prcm_partition possible values are defined in mach-omap2/prcm44xx.h.
  */
 struct powerdomain {

@@ -121,6 +137,8 @@ struct powerdomain {
 	s64 timer;
 	s64 state_timer[PWRDM_MAX_PWRSTS];
 #endif
+	const u32 wakeup_lat[PWRDM_MAX_FUNC_PWRSTS];
+	struct pm_qos_request_list pm_qos_request;
 };
 
 /**

Figures are added to the power domains structs.

Note: the figures are preliminary figures. More accurate measurements are needed. Also the conditions of measurements shall be investigated and described.

Tested on OMAP3 Beagleboard in RET/OFF using wake-up latency constraints on MPU, CORE and PER.

Signed-off-by Jean Pihet <[email protected]>

---
 arch/arm/mach-omap2/powerdomains3xxx_data.c |   63 +++++++++++++++++++++++++++
 1 files changed, 63 insertions(+), 0 deletions(-)

arch/arm/mach-omap2/powerdomains3xxx_data.c +0 -0

index e1bec56..64973d1 100644

arch/arm/mach-omap2/powerdomains3xxx_data.c +60 -0

  */
 
 static struct powerdomain iva2_pwrdm = {

@@ -52,6 +55,12 @@ static struct powerdomain iva2_pwrdm = {
 		[2] = PWRSTS_OFF_ON,
 		[3] = PWRDM_POWER_ON,
 	},
+	.wakeup_lat = {
+		[PWRDM_FUNC_PWRST_OFF] = 1100,
+		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
+		[PWRDM_FUNC_PWRST_CSWR] = 350,
+		[PWRDM_FUNC_PWRST_ON] = 0,
+	},
 };
 
 static struct powerdomain mpu_3xxx_pwrdm = {

@@ -68,6 +77,12 @@ static struct powerdomain mpu_3xxx_pwrdm = {
 	.pwrsts_mem_on	  = {
 		[0] = PWRSTS_OFF_ON,
 	},
+	.wakeup_lat = {
+		[PWRDM_FUNC_PWRST_OFF] = 95,
+		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
+		[PWRDM_FUNC_PWRST_CSWR] = 45,
+		[PWRDM_FUNC_PWRST_ON] = 0,
+	},
 };
 
 /*

@@ -98,6 +113,12 @@ static struct powerdomain core_3xxx_pre_es3_1_pwrdm = {
 		[0] = PWRSTS_OFF_RET_ON, /* MEM1ONSTATE */
 		[1] = PWRSTS_OFF_RET_ON, /* MEM2ONSTATE */
 	},
+	.wakeup_lat = {
+		[PWRDM_FUNC_PWRST_OFF] = 100,
+		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
+		[PWRDM_FUNC_PWRST_CSWR] = 60,
+		[PWRDM_FUNC_PWRST_ON] = 0,
+	},
 };
 
 static struct powerdomain core_3xxx_es3_1_pwrdm = {

@@ -121,6 +142,12 @@ static struct powerdomain core_3xxx_es3_1_pwrdm = {
 		[0] = PWRSTS_OFF_RET_ON, /* MEM1ONSTATE */
 		[1] = PWRSTS_OFF_RET_ON, /* MEM2ONSTATE */
 	},
+	.wakeup_lat = {
+		[PWRDM_FUNC_PWRST_OFF] = 100,
+		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
+		[PWRDM_FUNC_PWRST_CSWR] = 60,
+		[PWRDM_FUNC_PWRST_ON] = 0,
+	},
 };
 
 static struct powerdomain dss_pwrdm = {

@@ -136,6 +163,12 @@ static struct powerdomain dss_pwrdm = {
 	.pwrsts_mem_on	  = {
 		[0] = PWRDM_POWER_ON,  /* MEMONSTATE */
 	},
+	.wakeup_lat = {
+		[PWRDM_FUNC_PWRST_OFF] = 70,
+		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
+		[PWRDM_FUNC_PWRST_CSWR] = 20,
+		[PWRDM_FUNC_PWRST_ON] = 0,
+	},
 };
 
 /*

@@ -157,6 +190,12 @@ static struct powerdomain sgx_pwrdm = {
 	.pwrsts_mem_on	  = {
 		[0] = PWRDM_POWER_ON,  /* MEMONSTATE */
 	},
+	.wakeup_lat = {
+		[PWRDM_FUNC_PWRST_OFF] = 1000,
+		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
+		[PWRDM_FUNC_PWRST_CSWR] = UNSUP_STATE,
+		[PWRDM_FUNC_PWRST_ON] = 0,
+	},
 };
 
 static struct powerdomain cam_pwrdm = {

@@ -172,6 +211,12 @@ static struct powerdomain cam_pwrdm = {
 	.pwrsts_mem_on	  = {
 		[0] = PWRDM_POWER_ON,  /* MEMONSTATE */
 	},
+	.wakeup_lat = {
+		[PWRDM_FUNC_PWRST_OFF] = 850,
+		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
+		[PWRDM_FUNC_PWRST_CSWR] = 35,
+		[PWRDM_FUNC_PWRST_ON] = 0,
+	},
 };
 
 static struct powerdomain per_pwrdm = {

@@ -187,6 +232,12 @@ static struct powerdomain per_pwrdm = {
 	.pwrsts_mem_on	  = {
 		[0] = PWRDM_POWER_ON,  /* MEMONSTATE */
 	},
+	.wakeup_lat = {
+		[PWRDM_FUNC_PWRST_OFF] = 200,
+		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
+		[PWRDM_FUNC_PWRST_CSWR] = 110,
+		[PWRDM_FUNC_PWRST_ON] = 0,
+	},
 };
 
 static struct powerdomain emu_pwrdm = {

@@ -201,6 +252,12 @@ static struct powerdomain neon_pwrdm = {
 	.omap_chip	  = OMAP_CHIP_INIT(CHIP_IS_OMAP3430),
 	.pwrsts		  = PWRSTS_OFF_RET_ON,
 	.pwrsts_logic_ret = PWRDM_POWER_RET,
+	.wakeup_lat = {
+		[PWRDM_FUNC_PWRST_OFF] = 200,
+		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
+		[PWRDM_FUNC_PWRST_CSWR] = 35,
+		[PWRDM_FUNC_PWRST_ON] = 0,
+	},
 };
 
 static struct powerdomain usbhost_pwrdm = {

@@ -223,6 +280,12 @@ static struct powerdomain usbhost_pwrdm = {
 	.pwrsts_mem_on	  = {
 		[0] = PWRDM_POWER_ON,  /* MEMONSTATE */
 	},
+	.wakeup_lat = {
+		[PWRDM_FUNC_PWRST_OFF] = 800,
+		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
+		[PWRDM_FUNC_PWRST_CSWR] = 150,
+		[PWRDM_FUNC_PWRST_ON] = 0,
+	},
 };
 
 static struct powerdomain dpll1_pwrdm = {