device: Add device:: Msi_data pointer and struct msi_device_data

Create struct msi_device_data and add a pointer of that type to struct
dev_msi_info, which is part of struct device. Provide an allocator function
which can be invoked from the MSI interrupt allocation code pathes.

Add a properties field to the data structure as a first member so the
allocation size is not zero bytes. The field will be uses later on.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Nishanth Menon <nm@ti.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20211210221813.676660809@linutronix.de

include/linux/device.h

@@ -45,6 +45,7 @@ struct iommu_ops;
 struct iommu_group;
 struct dev_pin_info;
 struct dev_iommu;
+struct msi_device_data;
 
 /**
  * struct subsys_interface - interfaces to device functions
@@ -374,11 +375,15 @@ struct dev_links_info {
 /**
  * struct dev_msi_info - Device data related to MSI
  * @domain:	The MSI interrupt domain associated to the device
+ * @data:	Pointer to MSI device data
  */
 struct dev_msi_info {
 #ifdef CONFIG_GENERIC_MSI_IRQ_DOMAIN
 	struct irq_domain	*domain;
 #endif
+#ifdef CONFIG_GENERIC_MSI_IRQ
+	struct msi_device_data	*data;
+#endif
 };
 
 /**

include/linux/msi.h

@@ -171,6 +171,16 @@ struct msi_desc {
 	};
 };
 
+/**
+ * msi_device_data - MSI per device data
+ * @properties:		MSI properties which are interesting to drivers
+ */
+struct msi_device_data {
+	unsigned long			properties;
+};
+
+int msi_setup_device_data(struct device *dev);
+
 /* Helpers to hide struct msi_desc implementation details */
 #define msi_desc_to_dev(desc)		((desc)->dev)
 #define dev_to_msi_list(dev)		(&(dev)->msi_list)
@@ -233,10 +243,16 @@ void pci_msi_mask_irq(struct irq_data *data);
 void pci_msi_unmask_irq(struct irq_data *data);
 
 #ifdef CONFIG_SYSFS
+int msi_device_populate_sysfs(struct device *dev);
+void msi_device_destroy_sysfs(struct device *dev);
+
 const struct attribute_group **msi_populate_sysfs(struct device *dev);
 void msi_destroy_sysfs(struct device *dev,
 		       const struct attribute_group **msi_irq_groups);
 #else
+static inline int msi_device_populate_sysfs(struct device *dev) { return 0; }
+static inline void msi_device_destroy_sysfs(struct device *dev) { }
+
 static inline const struct attribute_group **msi_populate_sysfs(struct device *dev)
 {
 	return NULL;
@@ -384,6 +400,8 @@ enum {
 	MSI_FLAG_MUST_REACTIVATE	= (1 << 5),
 	/* Is level-triggered capable, using two messages */
 	MSI_FLAG_LEVEL_CAPABLE		= (1 << 6),
+	/* Populate sysfs on alloc() and destroy it on free() */
+	MSI_FLAG_DEV_SYSFS		= (1 << 7),
 };
 
 int msi_domain_set_affinity(struct irq_data *data, const struct cpumask *mask,

kernel/irq/msi.c

@@ -73,6 +73,38 @@ void get_cached_msi_msg(unsigned int irq, struct msi_msg *msg)
 }
 EXPORT_SYMBOL_GPL(get_cached_msi_msg);
 
+static void msi_device_data_release(struct device *dev, void *res)
+{
+	WARN_ON_ONCE(!list_empty(&dev->msi_list));
+	dev->msi.data = NULL;
+}
+
+/**
+ * msi_setup_device_data - Setup MSI device data
+ * @dev:	Device for which MSI device data should be set up
+ *
+ * Return: 0 on success, appropriate error code otherwise
+ *
+ * This can be called more than once for @dev. If the MSI device data is
+ * already allocated the call succeeds. The allocated memory is
+ * automatically released when the device is destroyed.
+ */
+int msi_setup_device_data(struct device *dev)
+{
+	struct msi_device_data *md;
+
+	if (dev->msi.data)
+		return 0;
+
+	md = devres_alloc(msi_device_data_release, sizeof(*md), GFP_KERNEL);
+	if (!md)
+		return -ENOMEM;
+
+	dev->msi.data = md;
+	devres_add(dev, md);
+	return 0;
+}
+
 #ifdef CONFIG_SYSFS
 static ssize_t msi_mode_show(struct device *dev, struct device_attribute *attr,
 			     char *buf)