Jean Pihet <[email protected]> writes:
> 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: ...
> ---
> 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(-)
>
> diff --git a/arch/arm/plat-omap/include/plat/omap_device.h
> b/arch/arm/plat-omap/include/plat/omap_device.h
> index e4c349f..d4766c4 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;
>
> @@ -73,6 +75,15 @@ struct omap_device {
> s8 pm_lat_level;
> 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?
> + 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 */
> diff --git a/arch/arm/plat-omap/omap_device.c
> b/arch/arm/plat-omap/omap_device.c
> index 9bbda9a..9199d3e 100644
> --- a/arch/arm/plat-omap/omap_device.c
> +++ b/arch/arm/plat-omap/omap_device.c
> @@ -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) {
> + 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'.
> + 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 */
> + if (user->target == target) {
> + ret = user->constraint_value;
> + break;
> + }
> + }
> + }
Hmm, why can't you use plist_first() and plist_last() here?
> +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;
> + struct omap_hwmod *oh;
> + struct platform_device *pdev;
> + struct powerdomain *pwrdm = NULL;
> + u32 ret = -EINVAL;
> +
> + /* 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.
> + 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;
> + }
> +
> + /* 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
> + 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;
> + }
> +
> + /*
> + * 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.
> + } 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)
> {
> + /* 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
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