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genirq/msi: Provide a set of advanced MSI accessors and iterators
In preparation for dynamic handling of MSI-X interrupts provide a new set of MSI descriptor accessor functions and iterators. They are benefitial per se as they allow to cleanup quite some code in various MSI domain implementations. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Michael Kelley <mikelley@microsoft.com> Tested-by: Nishanth Menon <nm@ti.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Link: https://lore.kernel.org/r/20211206210747.818635078@linutronix.de
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@ -140,6 +140,18 @@ struct msi_desc {
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struct pci_msi_desc pci;
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struct pci_msi_desc pci;
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};
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};
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/*
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* Filter values for the MSI descriptor iterators and accessor functions.
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*/
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enum msi_desc_filter {
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/* All descriptors */
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MSI_DESC_ALL,
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/* Descriptors which have no interrupt associated */
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MSI_DESC_NOTASSOCIATED,
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/* Descriptors which have an interrupt associated */
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MSI_DESC_ASSOCIATED,
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};
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/**
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/**
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* msi_device_data - MSI per device data
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* msi_device_data - MSI per device data
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* @properties: MSI properties which are interesting to drivers
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* @properties: MSI properties which are interesting to drivers
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@ -147,6 +159,7 @@ struct msi_desc {
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* @platform_data: Platform-MSI specific data
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* @platform_data: Platform-MSI specific data
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* @list: List of MSI descriptors associated to the device
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* @list: List of MSI descriptors associated to the device
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* @mutex: Mutex protecting the MSI list
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* @mutex: Mutex protecting the MSI list
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* @__next: Cached pointer to the next entry for iterators
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*/
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*/
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struct msi_device_data {
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struct msi_device_data {
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unsigned long properties;
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unsigned long properties;
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@ -154,6 +167,7 @@ struct msi_device_data {
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struct platform_msi_priv_data *platform_data;
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struct platform_msi_priv_data *platform_data;
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struct list_head list;
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struct list_head list;
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struct mutex mutex;
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struct mutex mutex;
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struct msi_desc *__next;
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};
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};
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int msi_setup_device_data(struct device *dev);
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int msi_setup_device_data(struct device *dev);
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@ -162,6 +176,25 @@ unsigned int msi_get_virq(struct device *dev, unsigned int index);
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void msi_lock_descs(struct device *dev);
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void msi_lock_descs(struct device *dev);
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void msi_unlock_descs(struct device *dev);
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void msi_unlock_descs(struct device *dev);
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struct msi_desc *msi_first_desc(struct device *dev, enum msi_desc_filter filter);
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struct msi_desc *msi_next_desc(struct device *dev, enum msi_desc_filter filter);
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/**
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* msi_for_each_desc - Iterate the MSI descriptors
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*
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* @desc: struct msi_desc pointer used as iterator
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* @dev: struct device pointer - device to iterate
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* @filter: Filter for descriptor selection
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*
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* Notes:
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* - The loop must be protected with a msi_lock_descs()/msi_unlock_descs()
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* pair.
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* - It is safe to remove a retrieved MSI descriptor in the loop.
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*/
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#define msi_for_each_desc(desc, dev, filter) \
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for ((desc) = msi_first_desc((dev), (filter)); (desc); \
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(desc) = msi_next_desc((dev), (filter)))
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/* Helpers to hide struct msi_desc implementation details */
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/* Helpers to hide struct msi_desc implementation details */
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#define msi_desc_to_dev(desc) ((desc)->dev)
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#define msi_desc_to_dev(desc) ((desc)->dev)
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#define dev_to_msi_list(dev) (&(dev)->msi.data->list)
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#define dev_to_msi_list(dev) (&(dev)->msi.data->list)
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@ -125,10 +125,106 @@ EXPORT_SYMBOL_GPL(msi_lock_descs);
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*/
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*/
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void msi_unlock_descs(struct device *dev)
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void msi_unlock_descs(struct device *dev)
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{
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{
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/* Clear the next pointer which was cached by the iterator */
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dev->msi.data->__next = NULL;
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mutex_unlock(&dev->msi.data->mutex);
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mutex_unlock(&dev->msi.data->mutex);
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}
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}
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EXPORT_SYMBOL_GPL(msi_unlock_descs);
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EXPORT_SYMBOL_GPL(msi_unlock_descs);
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static bool msi_desc_match(struct msi_desc *desc, enum msi_desc_filter filter)
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{
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switch (filter) {
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case MSI_DESC_ALL:
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return true;
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case MSI_DESC_NOTASSOCIATED:
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return !desc->irq;
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case MSI_DESC_ASSOCIATED:
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return !!desc->irq;
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}
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WARN_ON_ONCE(1);
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return false;
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}
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static struct msi_desc *msi_find_first_desc(struct device *dev, enum msi_desc_filter filter)
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{
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struct msi_desc *desc;
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list_for_each_entry(desc, dev_to_msi_list(dev), list) {
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if (msi_desc_match(desc, filter))
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return desc;
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}
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return NULL;
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}
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/**
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* msi_first_desc - Get the first MSI descriptor of a device
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* @dev: Device to operate on
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* @filter: Descriptor state filter
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*
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* Must be called with the MSI descriptor mutex held, i.e. msi_lock_descs()
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* must be invoked before the call.
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*
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* Return: Pointer to the first MSI descriptor matching the search
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* criteria, NULL if none found.
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*/
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struct msi_desc *msi_first_desc(struct device *dev, enum msi_desc_filter filter)
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{
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struct msi_desc *desc;
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if (WARN_ON_ONCE(!dev->msi.data))
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return NULL;
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lockdep_assert_held(&dev->msi.data->mutex);
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desc = msi_find_first_desc(dev, filter);
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dev->msi.data->__next = desc ? list_next_entry(desc, list) : NULL;
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return desc;
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}
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EXPORT_SYMBOL_GPL(msi_first_desc);
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static struct msi_desc *__msi_next_desc(struct device *dev, enum msi_desc_filter filter,
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struct msi_desc *from)
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{
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struct msi_desc *desc = from;
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list_for_each_entry_from(desc, dev_to_msi_list(dev), list) {
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if (msi_desc_match(desc, filter))
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return desc;
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}
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return NULL;
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}
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/**
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* msi_next_desc - Get the next MSI descriptor of a device
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* @dev: Device to operate on
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*
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* The first invocation of msi_next_desc() has to be preceeded by a
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* successful incovation of __msi_first_desc(). Consecutive invocations are
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* only valid if the previous one was successful. All these operations have
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* to be done within the same MSI mutex held region.
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*
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* Return: Pointer to the next MSI descriptor matching the search
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* criteria, NULL if none found.
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*/
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struct msi_desc *msi_next_desc(struct device *dev, enum msi_desc_filter filter)
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{
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struct msi_device_data *data = dev->msi.data;
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struct msi_desc *desc;
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if (WARN_ON_ONCE(!data))
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return NULL;
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lockdep_assert_held(&data->mutex);
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if (!data->__next)
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return NULL;
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desc = __msi_next_desc(dev, filter, data->__next);
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dev->msi.data->__next = desc ? list_next_entry(desc, list) : NULL;
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return desc;
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}
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EXPORT_SYMBOL_GPL(msi_next_desc);
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/**
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/**
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* msi_get_virq - Return Linux interrupt number of a MSI interrupt
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* msi_get_virq - Return Linux interrupt number of a MSI interrupt
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* @dev: Device to operate on
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* @dev: Device to operate on
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