1 // SPDX-License-Identifier: GPL-2.0
3 * PCI Message Signaled Interrupt (MSI) - irqdomain support
5 #include <linux/acpi_iort.h>
6 #include <linux/irqdomain.h>
7 #include <linux/of_irq.h>
11 int pci_msi_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
13 struct irq_domain *domain;
15 domain = dev_get_msi_domain(&dev->dev);
16 if (domain && irq_domain_is_hierarchy(domain))
17 return msi_domain_alloc_irqs_descs_locked(domain, &dev->dev, nvec);
19 return pci_msi_legacy_setup_msi_irqs(dev, nvec, type);
22 void pci_msi_teardown_msi_irqs(struct pci_dev *dev)
24 struct irq_domain *domain;
26 domain = dev_get_msi_domain(&dev->dev);
27 if (domain && irq_domain_is_hierarchy(domain))
28 msi_domain_free_irqs_descs_locked(domain, &dev->dev);
30 pci_msi_legacy_teardown_msi_irqs(dev);
31 msi_free_msi_descs(&dev->dev);
35 * pci_msi_domain_write_msg - Helper to write MSI message to PCI config space
36 * @irq_data: Pointer to interrupt data of the MSI interrupt
37 * @msg: Pointer to the message
39 static void pci_msi_domain_write_msg(struct irq_data *irq_data, struct msi_msg *msg)
41 struct msi_desc *desc = irq_data_get_msi_desc(irq_data);
44 * For MSI-X desc->irq is always equal to irq_data->irq. For
45 * MSI only the first interrupt of MULTI MSI passes the test.
47 if (desc->irq == irq_data->irq)
48 __pci_write_msi_msg(desc, msg);
52 * pci_msi_domain_calc_hwirq - Generate a unique ID for an MSI source
53 * @desc: Pointer to the MSI descriptor
55 * The ID number is only used within the irqdomain.
57 static irq_hw_number_t pci_msi_domain_calc_hwirq(struct msi_desc *desc)
59 struct pci_dev *dev = msi_desc_to_pci_dev(desc);
61 return (irq_hw_number_t)desc->msi_index |
62 pci_dev_id(dev) << 11 |
63 (pci_domain_nr(dev->bus) & 0xFFFFFFFF) << 27;
66 static inline bool pci_msi_desc_is_multi_msi(struct msi_desc *desc)
68 return !desc->pci.msi_attrib.is_msix && desc->nvec_used > 1;
72 * pci_msi_domain_check_cap - Verify that @domain supports the capabilities
74 * @domain: The interrupt domain to check
75 * @info: The domain info for verification
76 * @dev: The device to check
79 * 0 if the functionality is supported
80 * 1 if Multi MSI is requested, but the domain does not support it
83 static int pci_msi_domain_check_cap(struct irq_domain *domain,
84 struct msi_domain_info *info,
87 struct msi_desc *desc = msi_first_desc(dev, MSI_DESC_ALL);
89 /* Special handling to support __pci_enable_msi_range() */
90 if (pci_msi_desc_is_multi_msi(desc) &&
91 !(info->flags & MSI_FLAG_MULTI_PCI_MSI))
94 if (desc->pci.msi_attrib.is_msix) {
95 if (!(info->flags & MSI_FLAG_PCI_MSIX))
98 if (info->flags & MSI_FLAG_MSIX_CONTIGUOUS) {
101 /* Check for gaps in the entry indices */
102 msi_for_each_desc(desc, dev, MSI_DESC_ALL) {
103 if (desc->msi_index != idx++)
111 static void pci_msi_domain_set_desc(msi_alloc_info_t *arg,
112 struct msi_desc *desc)
115 arg->hwirq = pci_msi_domain_calc_hwirq(desc);
118 static struct msi_domain_ops pci_msi_domain_ops_default = {
119 .set_desc = pci_msi_domain_set_desc,
120 .msi_check = pci_msi_domain_check_cap,
123 static void pci_msi_domain_update_dom_ops(struct msi_domain_info *info)
125 struct msi_domain_ops *ops = info->ops;
128 info->ops = &pci_msi_domain_ops_default;
130 if (ops->set_desc == NULL)
131 ops->set_desc = pci_msi_domain_set_desc;
132 if (ops->msi_check == NULL)
133 ops->msi_check = pci_msi_domain_check_cap;
137 static void pci_msi_domain_update_chip_ops(struct msi_domain_info *info)
139 struct irq_chip *chip = info->chip;
142 if (!chip->irq_write_msi_msg)
143 chip->irq_write_msi_msg = pci_msi_domain_write_msg;
145 chip->irq_mask = pci_msi_mask_irq;
146 if (!chip->irq_unmask)
147 chip->irq_unmask = pci_msi_unmask_irq;
151 * pci_msi_create_irq_domain - Create a MSI interrupt domain
152 * @fwnode: Optional fwnode of the interrupt controller
153 * @info: MSI domain info
154 * @parent: Parent irq domain
156 * Updates the domain and chip ops and creates a MSI interrupt domain.
159 * A domain pointer or NULL in case of failure.
161 struct irq_domain *pci_msi_create_irq_domain(struct fwnode_handle *fwnode,
162 struct msi_domain_info *info,
163 struct irq_domain *parent)
165 struct irq_domain *domain;
167 if (WARN_ON(info->flags & MSI_FLAG_LEVEL_CAPABLE))
168 info->flags &= ~MSI_FLAG_LEVEL_CAPABLE;
170 if (info->flags & MSI_FLAG_USE_DEF_DOM_OPS)
171 pci_msi_domain_update_dom_ops(info);
172 if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)
173 pci_msi_domain_update_chip_ops(info);
175 info->flags |= MSI_FLAG_ACTIVATE_EARLY | MSI_FLAG_DEV_SYSFS;
176 if (IS_ENABLED(CONFIG_GENERIC_IRQ_RESERVATION_MODE))
177 info->flags |= MSI_FLAG_MUST_REACTIVATE;
179 /* PCI-MSI is oneshot-safe */
180 info->chip->flags |= IRQCHIP_ONESHOT_SAFE;
182 domain = msi_create_irq_domain(fwnode, info, parent);
186 irq_domain_update_bus_token(domain, DOMAIN_BUS_PCI_MSI);
189 EXPORT_SYMBOL_GPL(pci_msi_create_irq_domain);
192 * Users of the generic MSI infrastructure expect a device to have a single ID,
193 * so with DMA aliases we have to pick the least-worst compromise. Devices with
194 * DMA phantom functions tend to still emit MSIs from the real function number,
195 * so we ignore those and only consider topological aliases where either the
196 * alias device or RID appears on a different bus number. We also make the
197 * reasonable assumption that bridges are walked in an upstream direction (so
198 * the last one seen wins), and the much braver assumption that the most likely
199 * case is that of PCI->PCIe so we should always use the alias RID. This echoes
200 * the logic from intel_irq_remapping's set_msi_sid(), which presumably works
201 * well enough in practice; in the face of the horrible PCIe<->PCI-X conditions
202 * for taking ownership all we can really do is close our eyes and hope...
204 static int get_msi_id_cb(struct pci_dev *pdev, u16 alias, void *data)
207 u8 bus = PCI_BUS_NUM(*pa);
209 if (pdev->bus->number != bus || PCI_BUS_NUM(alias) != bus)
216 * pci_msi_domain_get_msi_rid - Get the MSI requester id (RID)
217 * @domain: The interrupt domain
218 * @pdev: The PCI device.
220 * The RID for a device is formed from the alias, with a firmware
221 * supplied mapping applied
225 u32 pci_msi_domain_get_msi_rid(struct irq_domain *domain, struct pci_dev *pdev)
227 struct device_node *of_node;
228 u32 rid = pci_dev_id(pdev);
230 pci_for_each_dma_alias(pdev, get_msi_id_cb, &rid);
232 of_node = irq_domain_get_of_node(domain);
233 rid = of_node ? of_msi_map_id(&pdev->dev, of_node, rid) :
234 iort_msi_map_id(&pdev->dev, rid);
240 * pci_msi_get_device_domain - Get the MSI domain for a given PCI device
241 * @pdev: The PCI device
243 * Use the firmware data to find a device-specific MSI domain
244 * (i.e. not one that is set as a default).
246 * Returns: The corresponding MSI domain or NULL if none has been found.
248 struct irq_domain *pci_msi_get_device_domain(struct pci_dev *pdev)
250 struct irq_domain *dom;
251 u32 rid = pci_dev_id(pdev);
253 pci_for_each_dma_alias(pdev, get_msi_id_cb, &rid);
254 dom = of_msi_map_get_device_domain(&pdev->dev, rid, DOMAIN_BUS_PCI_MSI);
256 dom = iort_get_device_domain(&pdev->dev, rid,
262 * pci_dev_has_special_msi_domain - Check whether the device is handled by
263 * a non-standard PCI-MSI domain
264 * @pdev: The PCI device to check.
266 * Returns: True if the device irqdomain or the bus irqdomain is
267 * non-standard PCI/MSI.
269 bool pci_dev_has_special_msi_domain(struct pci_dev *pdev)
271 struct irq_domain *dom = dev_get_msi_domain(&pdev->dev);
274 dom = dev_get_msi_domain(&pdev->bus->dev);
279 return dom->bus_token != DOMAIN_BUS_PCI_MSI;