genirq/msi: Move MSI sysfs handling from PCI to MSI core

Move PCI's MSI sysfs code to the irq core so that other busses such as
platform can reuse it.

Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210813035628.6844-2-21cnbao@gmail.com

1 files changed, 134 insertions, 0 deletions

diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c
index bb18040efbe8..48ef144649e3 100644
--- a/kernel/irq/msi.c
+++ b/kernel/irq/msi.c
@@ -14,6 +14,7 @@
 #include <linux/irqdomain.h>
 #include <linux/msi.h>
 #include <linux/slab.h>
+#include <linux/pci.h>
 
 #include "internals.h"
 
@@ -71,6 +72,139 @@ void get_cached_msi_msg(unsigned int irq, struct msi_msg *msg)
 }
 EXPORT_SYMBOL_GPL(get_cached_msi_msg);
 
+static ssize_t msi_mode_show(struct device *dev, struct device_attribute *attr,
+			     char *buf)
+{
+	struct msi_desc *entry;
+	bool is_msix = false;
+	unsigned long irq;
+	int retval;
+
+	retval = kstrtoul(attr->attr.name, 10, &irq);
+	if (retval)
+		return retval;
+
+	entry = irq_get_msi_desc(irq);
+	if (!entry)
+		return -ENODEV;
+
+	if (dev_is_pci(dev))
+		is_msix = entry->msi_attrib.is_msix;
+
+	return sysfs_emit(buf, "%s\n", is_msix ? "msix" : "msi");
+}
+
+/**
+ * msi_populate_sysfs - Populate msi_irqs sysfs entries for devices
+ * @dev:	The device(PCI, platform etc) who will get sysfs entries
+ *
+ * Return attribute_group ** so that specific bus MSI can save it to
+ * somewhere during initilizing msi irqs. If devices has no MSI irq,
+ * return NULL; if it fails to populate sysfs, return ERR_PTR
+ */
+const struct attribute_group **msi_populate_sysfs(struct device *dev)
+{
+	const struct attribute_group **msi_irq_groups;
+	struct attribute **msi_attrs, *msi_attr;
+	struct device_attribute *msi_dev_attr;
+	struct attribute_group *msi_irq_group;
+	struct msi_desc *entry;
+	int ret = -ENOMEM;
+	int num_msi = 0;
+	int count = 0;
+	int i;
+
+	/* Determine how many msi entries we have */
+	for_each_msi_entry(entry, dev)
+		num_msi += entry->nvec_used;
+	if (!num_msi)
+		return NULL;
+
+	/* Dynamically create the MSI attributes for the device */
+	msi_attrs = kcalloc(num_msi + 1, sizeof(void *), GFP_KERNEL);
+	if (!msi_attrs)
+		return ERR_PTR(-ENOMEM);
+
+	for_each_msi_entry(entry, dev) {
+		for (i = 0; i < entry->nvec_used; i++) {
+			msi_dev_attr = kzalloc(sizeof(*msi_dev_attr), GFP_KERNEL);
+			if (!msi_dev_attr)
+				goto error_attrs;
+			msi_attrs[count] = &msi_dev_attr->attr;
+
+			sysfs_attr_init(&msi_dev_attr->attr);
+			msi_dev_attr->attr.name = kasprintf(GFP_KERNEL, "%d",
+							    entry->irq + i);
+			if (!msi_dev_attr->attr.name)
+				goto error_attrs;
+			msi_dev_attr->attr.mode = 0444;
+			msi_dev_attr->show = msi_mode_show;
+			++count;
+		}
+	}
+
+	msi_irq_group = kzalloc(sizeof(*msi_irq_group), GFP_KERNEL);
+	if (!msi_irq_group)
+		goto error_attrs;
+	msi_irq_group->name = "msi_irqs";
+	msi_irq_group->attrs = msi_attrs;
+
+	msi_irq_groups = kcalloc(2, sizeof(void *), GFP_KERNEL);
+	if (!msi_irq_groups)
+		goto error_irq_group;
+	msi_irq_groups[0] = msi_irq_group;
+
+	ret = sysfs_create_groups(&dev->kobj, msi_irq_groups);
+	if (ret)
+		goto error_irq_groups;
+
+	return msi_irq_groups;
+
+error_irq_groups:
+	kfree(msi_irq_groups);
+error_irq_group:
+	kfree(msi_irq_group);
+error_attrs:
+	count = 0;
+	msi_attr = msi_attrs[count];
+	while (msi_attr) {
+		msi_dev_attr = container_of(msi_attr, struct device_attribute, attr);
+		kfree(msi_attr->name);
+		kfree(msi_dev_attr);
+		++count;
+		msi_attr = msi_attrs[count];
+	}
+	kfree(msi_attrs);
+	return ERR_PTR(ret);
+}
+
+/**
+ * msi_destroy_sysfs - Destroy msi_irqs sysfs entries for devices
+ * @dev:		The device(PCI, platform etc) who will remove sysfs entries
+ * @msi_irq_groups:	attribute_group for device msi_irqs entries
+ */
+void msi_destroy_sysfs(struct device *dev, const struct attribute_group **msi_irq_groups)
+{
+	struct device_attribute *dev_attr;
+	struct attribute **msi_attrs;
+	int count = 0;
+
+	if (msi_irq_groups) {
+		sysfs_remove_groups(&dev->kobj, msi_irq_groups);
+		msi_attrs = msi_irq_groups[0]->attrs;
+		while (msi_attrs[count]) {
+			dev_attr = container_of(msi_attrs[count],
+					struct device_attribute, attr);
+			kfree(dev_attr->attr.name);
+			kfree(dev_attr);
+			++count;
+		}
+		kfree(msi_attrs);
+		kfree(msi_irq_groups[0]);
+		kfree(msi_irq_groups);
+	}
+}
+
 #ifdef CONFIG_GENERIC_MSI_IRQ_DOMAIN
 static inline void irq_chip_write_msi_msg(struct irq_data *data,
 					  struct msi_msg *msg)