[PATCH 6/8] OMAP2+: omap_device: implement the constraints management code
jean.pihet at newoldbits.com
jean.pihet at newoldbits.com
Wed May 4 09:35:15 EDT 2011
From: Jean Pihet <j-pihet at ti.com>
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 <j-pihet at ti.com>
---
arch/arm/plat-omap/include/plat/omap_device.h | 15 ++-
arch/arm/plat-omap/omap_device.c | 191 +++++++++++++++++++++++++
2 files changed, 205 insertions(+), 1 deletions(-)
diff --git a/arch/arm/plat-omap/include/plat/omap_device.h b/arch/arm/plat-omap/include/plat/omap_device.h
index e4c349f..9a47b47 100644
--- a/arch/arm/plat-omap/include/plat/omap_device.h
+++ b/arch/arm/plat-omap/include/plat/omap_device.h
@@ -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;
@@ -54,8 +56,8 @@ extern struct device omap_device_parent;
* @pm_lat_level: array index of the last odpl entry executed - -1 if never
* @dev_wakeup_lat: dev wakeup latency in nanoseconds
* @_dev_wakeup_lat_limit: dev wakeup latency limit in nsec - set by OMAP PM
+ * @wkup_lat_plist_head: devices wake-up latency constraints list
* @_state: one of OMAP_DEVICE_STATE_* (see above)
- * @flags: device flags
*
* Integrates omap_hwmod data into Linux platform_device.
*
@@ -67,6 +69,7 @@ struct omap_device {
struct platform_device pdev;
struct omap_hwmod **hwmods;
struct omap_device_pm_latency *pm_lats;
+ struct plist_head wkup_lat_plist_head;
u32 dev_wakeup_lat;
u32 _dev_wakeup_lat_limit;
u8 pm_lats_cnt;
@@ -75,6 +78,13 @@ struct omap_device {
u8 _state;
};
+/* Linked list for the devices constraints entries */
+struct omap_device_constraints_entry {
+ struct device *dev;
+ struct device *req_dev;
+ struct plist_node node;
+};
+
/* Device driver interface (call via platform_data fn ptrs) */
int omap_device_enable(struct platform_device *pdev);
@@ -107,6 +117,9 @@ 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 */
diff --git a/arch/arm/plat-omap/omap_device.c b/arch/arm/plat-omap/omap_device.c
index 9bbda9a..1d075cb 100644
--- a/arch/arm/plat-omap/omap_device.c
+++ b/arch/arm/plat-omap/omap_device.c
@@ -292,10 +292,196 @@ static void _add_optional_clock_clkdev(struct omap_device *od,
}
}
+/* Spinlock that protects the constraints lists */
+static spinlock_t _constraints_lock;
+
+/*
+ * _store_constraint: add/update/remove a constraint from a plist. There is
+ * one plist per omap_device.
+ *
+ * @constraints_list: plist to use
+ * @req_dev: constraint requester, used to track the requests
+ * @dev: device constraint target, used to track the requests
+ * @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.
+ *
+ * Tracks the constraints by req_dev and dev.
+ * Returns the strongest constraint value for the given device, 0 in the
+ * case there is no constraint 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, struct device *dev,
+ long value, int ascending)
+{
+ struct omap_device_constraints_entry *user = NULL, *tmp_user;
+ int ret = 0;
+ unsigned long flags;
+
+ /* Check if there already is a constraint for dev and req_dev */
+ spin_lock_irqsave(&_constraints_lock, flags);
+ plist_for_each_entry(tmp_user, constraints_list, node) {
+ if ((tmp_user->req_dev == req_dev) && (tmp_user->dev == dev)) {
+ user = tmp_user;
+ break;
+ }
+ }
+ spin_unlock_irqrestore(&_constraints_lock, flags);
+
+ if (value >= 0) {
+ /* Nothing to update, job done */
+ if (user && (user->node.prio == value))
+ goto exit_ok;
+
+ /* Add new entry to the list or update existing request */
+ if (!user) {
+ 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;
+ user->dev = dev;
+ } else {
+ spin_lock_irqsave(&_constraints_lock, flags);
+ plist_del(&user->node, constraints_list);
+ spin_unlock_irqrestore(&_constraints_lock, flags);
+ }
+
+ spin_lock_irqsave(&_constraints_lock, flags);
+ plist_node_init(&user->node, value);
+ plist_add(&user->node, constraints_list);
+ spin_unlock_irqrestore(&_constraints_lock, flags);
+ } else {
+ /* Remove the constraint from the list */
+ if (!user) {
+ pr_err("%s: Error: no prior constraint to release\n",
+ __func__);
+ ret = -EINVAL;
+ goto exit_error;
+ }
+
+ spin_lock_irqsave(&_constraints_lock, flags);
+ plist_del(&user->node, constraints_list);
+ spin_unlock_irqrestore(&_constraints_lock, flags);
+ kfree(user);
+ }
+
+exit_ok:
+ /* Find the strongest constraint for the given device */
+ if (!plist_head_empty(constraints_list)) {
+ spin_lock_irqsave(&_constraints_lock, flags);
+ if (ascending) {
+ /* Find the lowest (i.e. first) value */
+ ret = plist_first(constraints_list)->prio;
+ } else {
+ /* Find the highest (i.e. last) value */
+ ret = plist_last(constraints_list)->prio;
+ }
+ spin_unlock_irqrestore(&_constraints_lock, flags);
+ }
+
+exit_error:
+ 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;
+ struct omap_hwmod *oh;
+ struct platform_device *pdev;
+ void *cookie = NULL;
+ u32 ret = -EINVAL;
+
+ /* Only valid for omap_devices */
+ if (dev->parent != &omap_device_parent) {
+ pr_err("%s: Error: not an omap_device %s\n",
+ __func__, dev_name(dev));
+ return -EINVAL;
+ }
+
+ /* Look for the platform device for dev */
+ pdev = to_platform_device(dev);
+
+ /* Try to catch non platform devices. */
+ if (pdev->name == NULL) {
+ 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 || (od->hwmods_cnt != 1)) {
+ pr_err("%s: Error: No unique hwmod for device %s\n",
+ __func__, dev_name(dev));
+ return -EINVAL;
+ }
+
+ /* Find the primary omap_hwmod for dev */
+ oh = od->hwmods[0];
+
+ switch (class) {
+ case OMAP_PM_CONSTRAINT_WKUP_LAT:
+ /*
+ * Store the constraint in the appropriate list and find the
+ * strongest constraint
+ */
+ ret = _store_constraint(&od->wkup_lat_plist_head,
+ req_dev, dev, t, 1);
+
+ /* Apply the constraint by calling the low level code */
+ cookie = (void *) &od->wkup_lat_plist_head;
+ if (ret >= 0) {
+ ret = omap_hwmod_set_wkup_lat_constraint(oh, cookie,
+ ret);
+ } 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 *
*
@@ -489,6 +675,8 @@ struct omap_device *omap_device_build_ss(const char *pdev_name, int pdev_id,
od->pm_lats = pm_lats;
od->pm_lats_cnt = pm_lats_cnt;
+ plist_head_init(&od->wkup_lat_plist_head, &_constraints_lock);
+
if (is_early_device)
ret = omap_early_device_register(od);
else
@@ -824,6 +1012,9 @@ struct device omap_device_parent = {
static int __init omap_device_init(void)
{
+ /* Initialize priority ordered list for wakeup latency constraint */
+ spin_lock_init(&_constraints_lock);
+
return device_register(&omap_device_parent);
}
core_initcall(omap_device_init);
--
1.7.2.5
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