diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/irq/msi.c | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c index 8e653f089f82..c368116e8b08 100644 --- a/kernel/irq/msi.c +++ b/kernel/irq/msi.c @@ -788,6 +788,47 @@ struct irq_domain *msi_create_irq_domain(struct fwnode_handle *fwnode, return domain; } +/** + * msi_parent_init_dev_msi_info - Delegate initialization of device MSI info down + * in the domain hierarchy + * @dev: The device for which the domain should be created + * @domain: The domain in the hierarchy this op is being called on + * @msi_parent_domain: The IRQ_DOMAIN_FLAG_MSI_PARENT domain for the child to + * be created + * @msi_child_info: The MSI domain info of the IRQ_DOMAIN_FLAG_MSI_DEVICE + * domain to be created + * + * Return: true on success, false otherwise + * + * This is the most complex problem of per device MSI domains and the + * underlying interrupt domain hierarchy: + * + * The device domain to be initialized requests the broadest feature set + * possible and the underlying domain hierarchy puts restrictions on it. + * + * That's trivial for a simple parent->child relationship, but it gets + * interesting with an intermediate domain: root->parent->child. The + * intermediate 'parent' can expand the capabilities which the 'root' + * domain is providing. So that creates a classic hen and egg problem: + * Which entity is doing the restrictions/expansions? + * + * One solution is to let the root domain handle the initialization that's + * why there is the @domain and the @msi_parent_domain pointer. + */ +bool msi_parent_init_dev_msi_info(struct device *dev, struct irq_domain *domain, + struct irq_domain *msi_parent_domain, + struct msi_domain_info *msi_child_info) +{ + struct irq_domain *parent = domain->parent; + + if (WARN_ON_ONCE(!parent || !parent->msi_parent_ops || + !parent->msi_parent_ops->init_dev_msi_info)) + return false; + + return parent->msi_parent_ops->init_dev_msi_info(dev, parent, msi_parent_domain, + msi_child_info); +} + int msi_domain_prepare_irqs(struct irq_domain *domain, struct device *dev, int nvec, msi_alloc_info_t *arg) { |