On Thu, Jun 14, 2012 at 10:05 AM, Jean Pihet <jean.pihet@xxxxxxxxxxxxxx> wrote:
Minor comment follows:
[...]
> +/**
> + * _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 PM_QOS_DEV_LAT_DEFAULT_VALUE 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.
> + * The power domains get the next power state programmed directly in the
> + * registers.
> + *
> + * Returns 0 in case of success, -EINVAL in case of invalid parameters,
> + * or the return value from omap_set_pwrdm_state.
> + */
> +static int _pwrdm_wakeuplat_update_pwrst(struct powerdomain *pwrdm,
> + long min_latency)
> +{
> + int ret = 0, state, new_state = PWRDM_FUNC_PWRST_ON;
> +
> + if (!pwrdm) {
> + WARN(1, "powerdomain: %s: invalid parameter(s)", __func__);
> + return -EINVAL;
> + }
_pwrdm_wakeuplat_update_pwrst is an helper function, we check pwrdm to
be valid here,
however,
[...]
> /* Public functions */
> /**
> + * pwrdm_wakeuplat_update_constraint - Set or update a powerdomain wakeup
> + * latency constraint and apply it
> + * @pwrdm: struct powerdomain * which the constraint applies to
> + * @cookie: constraint identifier, used for tracking
> + * @min_latency: minimum wakeup latency constraint (in microseconds) for
> + * the given pwrdm
> + *
> + * Tracks the constraints by @cookie.
> + * Constraint set/update: Adds a new entry to powerdomain's wake-up latency
> + * constraint list. If the constraint identifier already exists in the list,
> + * the old value is overwritten.
> + *
> + * Applies the aggregated constraint value for the given pwrdm by calling
> + * _pwrdm_wakeuplat_update_pwrst.
> + *
> + * Returns 0 upon success, -ENOMEM in case of memory shortage, -EINVAL in
> + * case of invalid latency value, or the return value from
> + * _pwrdm_wakeuplat_update_pwrst.
> + *
> + * The caller must check the validity of the parameters.
> + */
> +int pwrdm_wakeuplat_update_constraint(struct powerdomain *pwrdm, void *cookie,
> + long min_latency)
> +{
> + struct pwrdm_wkup_constraints_entry *tmp_user, *new_user, *user = NULL;
> + long value = PM_QOS_DEV_LAT_DEFAULT_VALUE;
> + int free_new_user = 0;
> +
> + pr_debug("powerdomain: %s: pwrdm %s, cookie=0x%p, min_latency=%ld\n",
> + __func__, pwrdm->name, cookie, min_latency);
here,
> +
> + if (min_latency <= PM_QOS_DEV_LAT_DEFAULT_VALUE) {
> + pr_warn("%s: min_latency >= PM_QOS_DEV_LAT_DEFAULT_VALUE\n",
> + __func__);
> + return -EINVAL;
> + }
> +
> + /* Allocate a new entry for insertion in the list */
> + new_user = kzalloc(sizeof(struct pwrdm_wkup_constraints_entry),
> + GFP_KERNEL);
> + if (!new_user) {
> + pr_err("%s: FATAL ERROR: kzalloc failed\n", __func__);
> + return -ENOMEM;
> + }
> +
> + mutex_lock(&pwrdm->wkup_lat_plist_lock);
here,
> +
> + /* Check if there already is a constraint for cookie */
> + plist_for_each_entry(tmp_user, &pwrdm->wkup_lat_plist_head, node) {
> + if (tmp_user->cookie == cookie) {
> + user = tmp_user;
> + break;
> + }
> + }
here,
> +
> + /* If nothing to update, job done */
> + if (user && (user->node.prio == min_latency))
> + goto out;
> +
> + if (!user) {
> + /* Add new entry to the list */
> + user = new_user;
> + user->cookie = cookie;
> + } else {
> + /* Update existing entry */
> + plist_del(&user->node, &pwrdm->wkup_lat_plist_head);
here
> + free_new_user = 1;
> + }
> +
> + plist_node_init(&user->node, min_latency);
> + plist_add(&user->node, &pwrdm->wkup_lat_plist_head);
here
> +
> + /* Find the aggregated constraint value from the list */
> + if (!plist_head_empty(&pwrdm->wkup_lat_plist_head))
...
> + value = plist_first(&pwrdm->wkup_lat_plist_head)->prio;
...
> +
> + mutex_unlock(&pwrdm->wkup_lat_plist_lock);
...
> +
> + /* Free the newly allocated entry if not in use */
> + if (free_new_user)
> + kfree(new_user);
> +
> + /* Apply the constraint to the pwrdm */
> + pr_debug("powerdomain: %s: pwrdm %s, value=%ld\n",
> + __func__, pwrdm->name, value);
...
> + return _pwrdm_wakeuplat_update_pwrst(pwrdm, value);
we have already crashed before we do a WARN in helper.
> +
> +out:
> + mutex_unlock(&pwrdm->wkup_lat_plist_lock);
> + return 0;
> +}
> +
> +/**
> + * pwrdm_wakeuplat_remove_constraint - Release a powerdomain wakeup latency
> + * constraint and apply it
> + * @pwrdm: struct powerdomain * which the constraint applies to
> + * @cookie: constraint identifier, used for tracking
> + *
> + * Tracks the constraints by @cookie.
> + * Constraint removal: Removes the identifier's entry from powerdomain's
> + * wakeup latency constraint list.
> + *
> + * Applies the aggregated constraint value for the given pwrdm by calling
> + * _pwrdm_wakeuplat_update_pwrst.
> + *
> + * Returns 0 upon success, -EINVAL in case the constraint to remove is not
> + * existing, or the return value from _pwrdm_wakeuplat_update_pwrst.
> + *
> + * The caller must check the validity of the parameters.
> + */
> +int pwrdm_wakeuplat_remove_constraint(struct powerdomain *pwrdm, void *cookie)
> +{
> + struct pwrdm_wkup_constraints_entry *tmp_user, *user = NULL;
> + long value = PM_QOS_DEV_LAT_DEFAULT_VALUE;
> +
> + pr_debug("powerdomain: %s: pwrdm %s, cookie=0x%p\n",
> + __func__, pwrdm->name, cookie);
... same story here as well.. and so on..
Regards,
Nishanth Menon
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