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(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(domain, &dev->dev);
30 pci_msi_legacy_teardown_msi_irqs(dev);
34 * pci_msi_domain_write_msg - Helper to write MSI message to PCI config space
35 * @irq_data: Pointer to interrupt data of the MSI interrupt
36 * @msg: Pointer to the message
38 static void pci_msi_domain_write_msg(struct irq_data *irq_data, struct msi_msg *msg)
40 struct msi_desc *desc = irq_data_get_msi_desc(irq_data);
43 * For MSI-X desc->irq is always equal to irq_data->irq. For
44 * MSI only the first interrupt of MULTI MSI passes the test.
46 if (desc->irq == irq_data->irq)
47 __pci_write_msi_msg(desc, msg);
51 * pci_msi_domain_calc_hwirq - Generate a unique ID for an MSI source
52 * @desc: Pointer to the MSI descriptor
54 * The ID number is only used within the irqdomain.
56 static irq_hw_number_t pci_msi_domain_calc_hwirq(struct msi_desc *desc)
58 struct pci_dev *dev = msi_desc_to_pci_dev(desc);
60 return (irq_hw_number_t)desc->msi_index |
61 pci_dev_id(dev) << 11 |
62 (pci_domain_nr(dev->bus) & 0xFFFFFFFF) << 27;
65 static inline bool pci_msi_desc_is_multi_msi(struct msi_desc *desc)
67 return !desc->pci.msi_attrib.is_msix && desc->nvec_used > 1;
71 * pci_msi_domain_check_cap - Verify that @domain supports the capabilities
73 * @domain: The interrupt domain to check
74 * @info: The domain info for verification
75 * @dev: The device to check
78 * 0 if the functionality is supported
79 * 1 if Multi MSI is requested, but the domain does not support it
82 static int pci_msi_domain_check_cap(struct irq_domain *domain,
83 struct msi_domain_info *info,
86 struct msi_desc *desc = first_pci_msi_entry(to_pci_dev(dev));
88 /* Special handling to support __pci_enable_msi_range() */
89 if (pci_msi_desc_is_multi_msi(desc) &&
90 !(info->flags & MSI_FLAG_MULTI_PCI_MSI))
92 else if (desc->pci.msi_attrib.is_msix && !(info->flags & MSI_FLAG_PCI_MSIX))
98 static void pci_msi_domain_set_desc(msi_alloc_info_t *arg,
99 struct msi_desc *desc)
102 arg->hwirq = pci_msi_domain_calc_hwirq(desc);
105 static struct msi_domain_ops pci_msi_domain_ops_default = {
106 .set_desc = pci_msi_domain_set_desc,
107 .msi_check = pci_msi_domain_check_cap,
110 static void pci_msi_domain_update_dom_ops(struct msi_domain_info *info)
112 struct msi_domain_ops *ops = info->ops;
115 info->ops = &pci_msi_domain_ops_default;
117 if (ops->set_desc == NULL)
118 ops->set_desc = pci_msi_domain_set_desc;
119 if (ops->msi_check == NULL)
120 ops->msi_check = pci_msi_domain_check_cap;
124 static void pci_msi_domain_update_chip_ops(struct msi_domain_info *info)
126 struct irq_chip *chip = info->chip;
129 if (!chip->irq_write_msi_msg)
130 chip->irq_write_msi_msg = pci_msi_domain_write_msg;
132 chip->irq_mask = pci_msi_mask_irq;
133 if (!chip->irq_unmask)
134 chip->irq_unmask = pci_msi_unmask_irq;
138 * pci_msi_create_irq_domain - Create a MSI interrupt domain
139 * @fwnode: Optional fwnode of the interrupt controller
140 * @info: MSI domain info
141 * @parent: Parent irq domain
143 * Updates the domain and chip ops and creates a MSI interrupt domain.
146 * A domain pointer or NULL in case of failure.
148 struct irq_domain *pci_msi_create_irq_domain(struct fwnode_handle *fwnode,
149 struct msi_domain_info *info,
150 struct irq_domain *parent)
152 struct irq_domain *domain;
154 if (WARN_ON(info->flags & MSI_FLAG_LEVEL_CAPABLE))
155 info->flags &= ~MSI_FLAG_LEVEL_CAPABLE;
157 if (info->flags & MSI_FLAG_USE_DEF_DOM_OPS)
158 pci_msi_domain_update_dom_ops(info);
159 if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)
160 pci_msi_domain_update_chip_ops(info);
162 info->flags |= MSI_FLAG_ACTIVATE_EARLY | MSI_FLAG_DEV_SYSFS;
163 if (IS_ENABLED(CONFIG_GENERIC_IRQ_RESERVATION_MODE))
164 info->flags |= MSI_FLAG_MUST_REACTIVATE;
166 /* PCI-MSI is oneshot-safe */
167 info->chip->flags |= IRQCHIP_ONESHOT_SAFE;
169 domain = msi_create_irq_domain(fwnode, info, parent);
173 irq_domain_update_bus_token(domain, DOMAIN_BUS_PCI_MSI);
176 EXPORT_SYMBOL_GPL(pci_msi_create_irq_domain);
179 * Users of the generic MSI infrastructure expect a device to have a single ID,
180 * so with DMA aliases we have to pick the least-worst compromise. Devices with
181 * DMA phantom functions tend to still emit MSIs from the real function number,
182 * so we ignore those and only consider topological aliases where either the
183 * alias device or RID appears on a different bus number. We also make the
184 * reasonable assumption that bridges are walked in an upstream direction (so
185 * the last one seen wins), and the much braver assumption that the most likely
186 * case is that of PCI->PCIe so we should always use the alias RID. This echoes
187 * the logic from intel_irq_remapping's set_msi_sid(), which presumably works
188 * well enough in practice; in the face of the horrible PCIe<->PCI-X conditions
189 * for taking ownership all we can really do is close our eyes and hope...
191 static int get_msi_id_cb(struct pci_dev *pdev, u16 alias, void *data)
194 u8 bus = PCI_BUS_NUM(*pa);
196 if (pdev->bus->number != bus || PCI_BUS_NUM(alias) != bus)
203 * pci_msi_domain_get_msi_rid - Get the MSI requester id (RID)
204 * @domain: The interrupt domain
205 * @pdev: The PCI device.
207 * The RID for a device is formed from the alias, with a firmware
208 * supplied mapping applied
212 u32 pci_msi_domain_get_msi_rid(struct irq_domain *domain, struct pci_dev *pdev)
214 struct device_node *of_node;
215 u32 rid = pci_dev_id(pdev);
217 pci_for_each_dma_alias(pdev, get_msi_id_cb, &rid);
219 of_node = irq_domain_get_of_node(domain);
220 rid = of_node ? of_msi_map_id(&pdev->dev, of_node, rid) :
221 iort_msi_map_id(&pdev->dev, rid);
227 * pci_msi_get_device_domain - Get the MSI domain for a given PCI device
228 * @pdev: The PCI device
230 * Use the firmware data to find a device-specific MSI domain
231 * (i.e. not one that is set as a default).
233 * Returns: The corresponding MSI domain or NULL if none has been found.
235 struct irq_domain *pci_msi_get_device_domain(struct pci_dev *pdev)
237 struct irq_domain *dom;
238 u32 rid = pci_dev_id(pdev);
240 pci_for_each_dma_alias(pdev, get_msi_id_cb, &rid);
241 dom = of_msi_map_get_device_domain(&pdev->dev, rid, DOMAIN_BUS_PCI_MSI);
243 dom = iort_get_device_domain(&pdev->dev, rid,
249 * pci_dev_has_special_msi_domain - Check whether the device is handled by
250 * a non-standard PCI-MSI domain
251 * @pdev: The PCI device to check.
253 * Returns: True if the device irqdomain or the bus irqdomain is
254 * non-standard PCI/MSI.
256 bool pci_dev_has_special_msi_domain(struct pci_dev *pdev)
258 struct irq_domain *dom = dev_get_msi_domain(&pdev->dev);
261 dom = dev_get_msi_domain(&pdev->bus->dev);
266 return dom->bus_token != DOMAIN_BUS_PCI_MSI;