1 files changed, 279 insertions, 0 deletions
diff --git a/drivers/pci/msi/irqdomain.c b/drivers/pci/msi/irqdomain.c
new file mode 100644
index 000000000000..123450e715cb
--- /dev/null
+++ b/drivers/pci/msi/irqdomain.c
@@ -0,0 +1,279 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * PCI Message Signaled Interrupt (MSI) - irqdomain support
+ */
+#include <linux/acpi_iort.h>
+#include <linux/irqdomain.h>
+#include <linux/of_irq.h>
+
+#include "msi.h"
+
+int pci_msi_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
+{
+	struct irq_domain *domain;
+
+	domain = dev_get_msi_domain(&dev->dev);
+	if (domain && irq_domain_is_hierarchy(domain))
+		return msi_domain_alloc_irqs(domain, &dev->dev, nvec);
+
+	return pci_msi_legacy_setup_msi_irqs(dev, nvec, type);
+}
+
+void pci_msi_teardown_msi_irqs(struct pci_dev *dev)
+{
+	struct irq_domain *domain;
+
+	domain = dev_get_msi_domain(&dev->dev);
+	if (domain && irq_domain_is_hierarchy(domain))
+		msi_domain_free_irqs(domain, &dev->dev);
+	else
+		pci_msi_legacy_teardown_msi_irqs(dev);
+}
+
+/**
+ * pci_msi_domain_write_msg - Helper to write MSI message to PCI config space
+ * @irq_data:	Pointer to interrupt data of the MSI interrupt
+ * @msg:	Pointer to the message
+ */
+static void pci_msi_domain_write_msg(struct irq_data *irq_data, struct msi_msg *msg)
+{
+	struct msi_desc *desc = irq_data_get_msi_desc(irq_data);
+
+	/*
+	 * For MSI-X desc->irq is always equal to irq_data->irq. For
+	 * MSI only the first interrupt of MULTI MSI passes the test.
+	 */
+	if (desc->irq == irq_data->irq)
+		__pci_write_msi_msg(desc, msg);
+}
+
+/**
+ * pci_msi_domain_calc_hwirq - Generate a unique ID for an MSI source
+ * @desc:	Pointer to the MSI descriptor
+ *
+ * The ID number is only used within the irqdomain.
+ */
+static irq_hw_number_t pci_msi_domain_calc_hwirq(struct msi_desc *desc)
+{
+	struct pci_dev *dev = msi_desc_to_pci_dev(desc);
+
+	return (irq_hw_number_t)desc->pci.msi_attrib.entry_nr |
+		pci_dev_id(dev) << 11 |
+		(pci_domain_nr(dev->bus) & 0xFFFFFFFF) << 27;
+}
+
+static inline bool pci_msi_desc_is_multi_msi(struct msi_desc *desc)
+{
+	return !desc->pci.msi_attrib.is_msix && desc->nvec_used > 1;
+}
+
+/**
+ * pci_msi_domain_check_cap - Verify that @domain supports the capabilities
+ *			      for @dev
+ * @domain:	The interrupt domain to check
+ * @info:	The domain info for verification
+ * @dev:	The device to check
+ *
+ * Returns:
+ *  0 if the functionality is supported
+ *  1 if Multi MSI is requested, but the domain does not support it
+ *  -ENOTSUPP otherwise
+ */
+int pci_msi_domain_check_cap(struct irq_domain *domain,
+			     struct msi_domain_info *info, struct device *dev)
+{
+	struct msi_desc *desc = first_pci_msi_entry(to_pci_dev(dev));
+
+	/* Special handling to support __pci_enable_msi_range() */
+	if (pci_msi_desc_is_multi_msi(desc) &&
+	    !(info->flags & MSI_FLAG_MULTI_PCI_MSI))
+		return 1;
+	else if (desc->pci.msi_attrib.is_msix && !(info->flags & MSI_FLAG_PCI_MSIX))
+		return -ENOTSUPP;
+
+	return 0;
+}
+
+static int pci_msi_domain_handle_error(struct irq_domain *domain,
+				       struct msi_desc *desc, int error)
+{
+	/* Special handling to support __pci_enable_msi_range() */
+	if (pci_msi_desc_is_multi_msi(desc) && error == -ENOSPC)
+		return 1;
+
+	return error;
+}
+
+static void pci_msi_domain_set_desc(msi_alloc_info_t *arg,
+				    struct msi_desc *desc)
+{
+	arg->desc = desc;
+	arg->hwirq = pci_msi_domain_calc_hwirq(desc);
+}
+
+static struct msi_domain_ops pci_msi_domain_ops_default = {
+	.set_desc	= pci_msi_domain_set_desc,
+	.msi_check	= pci_msi_domain_check_cap,
+	.handle_error	= pci_msi_domain_handle_error,
+};
+
+static void pci_msi_domain_update_dom_ops(struct msi_domain_info *info)
+{
+	struct msi_domain_ops *ops = info->ops;
+
+	if (ops == NULL) {
+		info->ops = &pci_msi_domain_ops_default;
+	} else {
+		if (ops->set_desc == NULL)
+			ops->set_desc = pci_msi_domain_set_desc;
+		if (ops->msi_check == NULL)
+			ops->msi_check = pci_msi_domain_check_cap;
+		if (ops->handle_error == NULL)
+			ops->handle_error = pci_msi_domain_handle_error;
+	}
+}
+
+static void pci_msi_domain_update_chip_ops(struct msi_domain_info *info)
+{
+	struct irq_chip *chip = info->chip;
+
+	BUG_ON(!chip);
+	if (!chip->irq_write_msi_msg)
+		chip->irq_write_msi_msg = pci_msi_domain_write_msg;
+	if (!chip->irq_mask)
+		chip->irq_mask = pci_msi_mask_irq;
+	if (!chip->irq_unmask)
+		chip->irq_unmask = pci_msi_unmask_irq;
+}
+
+/**
+ * pci_msi_create_irq_domain - Create a MSI interrupt domain
+ * @fwnode:	Optional fwnode of the interrupt controller
+ * @info:	MSI domain info
+ * @parent:	Parent irq domain
+ *
+ * Updates the domain and chip ops and creates a MSI interrupt domain.
+ *
+ * Returns:
+ * A domain pointer or NULL in case of failure.
+ */
+struct irq_domain *pci_msi_create_irq_domain(struct fwnode_handle *fwnode,
+					     struct msi_domain_info *info,
+					     struct irq_domain *parent)
+{
+	struct irq_domain *domain;
+
+	if (WARN_ON(info->flags & MSI_FLAG_LEVEL_CAPABLE))
+		info->flags &= ~MSI_FLAG_LEVEL_CAPABLE;
+
+	if (info->flags & MSI_FLAG_USE_DEF_DOM_OPS)
+		pci_msi_domain_update_dom_ops(info);
+	if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)
+		pci_msi_domain_update_chip_ops(info);
+
+	info->flags |= MSI_FLAG_ACTIVATE_EARLY;
+	if (IS_ENABLED(CONFIG_GENERIC_IRQ_RESERVATION_MODE))
+		info->flags |= MSI_FLAG_MUST_REACTIVATE;
+
+	/* PCI-MSI is oneshot-safe */
+	info->chip->flags |= IRQCHIP_ONESHOT_SAFE;
+
+	domain = msi_create_irq_domain(fwnode, info, parent);
+	if (!domain)
+		return NULL;
+
+	irq_domain_update_bus_token(domain, DOMAIN_BUS_PCI_MSI);
+	return domain;
+}
+EXPORT_SYMBOL_GPL(pci_msi_create_irq_domain);
+
+/*
+ * Users of the generic MSI infrastructure expect a device to have a single ID,
+ * so with DMA aliases we have to pick the least-worst compromise. Devices with
+ * DMA phantom functions tend to still emit MSIs from the real function number,
+ * so we ignore those and only consider topological aliases where either the
+ * alias device or RID appears on a different bus number. We also make the
+ * reasonable assumption that bridges are walked in an upstream direction (so
+ * the last one seen wins), and the much braver assumption that the most likely
+ * case is that of PCI->PCIe so we should always use the alias RID. This echoes
+ * the logic from intel_irq_remapping's set_msi_sid(), which presumably works
+ * well enough in practice; in the face of the horrible PCIe<->PCI-X conditions
+ * for taking ownership all we can really do is close our eyes and hope...
+ */
+static int get_msi_id_cb(struct pci_dev *pdev, u16 alias, void *data)
+{
+	u32 *pa = data;
+	u8 bus = PCI_BUS_NUM(*pa);
+
+	if (pdev->bus->number != bus || PCI_BUS_NUM(alias) != bus)
+		*pa = alias;
+
+	return 0;
+}
+
+/**
+ * pci_msi_domain_get_msi_rid - Get the MSI requester id (RID)
+ * @domain:	The interrupt domain
+ * @pdev:	The PCI device.
+ *
+ * The RID for a device is formed from the alias, with a firmware
+ * supplied mapping applied
+ *
+ * Returns: The RID.
+ */
+u32 pci_msi_domain_get_msi_rid(struct irq_domain *domain, struct pci_dev *pdev)
+{
+	struct device_node *of_node;
+	u32 rid = pci_dev_id(pdev);
+
+	pci_for_each_dma_alias(pdev, get_msi_id_cb, &rid);
+
+	of_node = irq_domain_get_of_node(domain);
+	rid = of_node ? of_msi_map_id(&pdev->dev, of_node, rid) :
+			iort_msi_map_id(&pdev->dev, rid);
+
+	return rid;
+}
+
+/**
+ * pci_msi_get_device_domain - Get the MSI domain for a given PCI device
+ * @pdev:	The PCI device
+ *
+ * Use the firmware data to find a device-specific MSI domain
+ * (i.e. not one that is set as a default).
+ *
+ * Returns: The corresponding MSI domain or NULL if none has been found.
+ */
+struct irq_domain *pci_msi_get_device_domain(struct pci_dev *pdev)
+{
+	struct irq_domain *dom;
+	u32 rid = pci_dev_id(pdev);
+
+	pci_for_each_dma_alias(pdev, get_msi_id_cb, &rid);
+	dom = of_msi_map_get_device_domain(&pdev->dev, rid, DOMAIN_BUS_PCI_MSI);
+	if (!dom)
+		dom = iort_get_device_domain(&pdev->dev, rid,
+					     DOMAIN_BUS_PCI_MSI);
+	return dom;
+}
+
+/**
+ * pci_dev_has_special_msi_domain - Check whether the device is handled by
+ *				    a non-standard PCI-MSI domain
+ * @pdev:	The PCI device to check.
+ *
+ * Returns: True if the device irqdomain or the bus irqdomain is
+ * non-standard PCI/MSI.
+ */
+bool pci_dev_has_special_msi_domain(struct pci_dev *pdev)
+{
+	struct irq_domain *dom = dev_get_msi_domain(&pdev->dev);
+
+	if (!dom)
+		dom = dev_get_msi_domain(&pdev->bus->dev);
+
+	if (!dom)
+		return true;
+
+	return dom->bus_token != DOMAIN_BUS_PCI_MSI;
+}