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path: root/drivers/irqchip/irq-gic-v3-its-pci-msi.c
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Diffstat (limited to 'drivers/irqchip/irq-gic-v3-its-pci-msi.c')
-rw-r--r--drivers/irqchip/irq-gic-v3-its-pci-msi.c202
1 files changed, 202 insertions, 0 deletions
diff --git a/drivers/irqchip/irq-gic-v3-its-pci-msi.c b/drivers/irqchip/irq-gic-v3-its-pci-msi.c
new file mode 100644
index 000000000..93f77a819
--- /dev/null
+++ b/drivers/irqchip/irq-gic-v3-its-pci-msi.c
@@ -0,0 +1,202 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2013-2015 ARM Limited, All Rights Reserved.
+ * Author: Marc Zyngier <marc.zyngier@arm.com>
+ */
+
+#include <linux/acpi_iort.h>
+#include <linux/pci.h>
+#include <linux/msi.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/of_pci.h>
+
+static void its_mask_msi_irq(struct irq_data *d)
+{
+ pci_msi_mask_irq(d);
+ irq_chip_mask_parent(d);
+}
+
+static void its_unmask_msi_irq(struct irq_data *d)
+{
+ pci_msi_unmask_irq(d);
+ irq_chip_unmask_parent(d);
+}
+
+static struct irq_chip its_msi_irq_chip = {
+ .name = "ITS-MSI",
+ .irq_unmask = its_unmask_msi_irq,
+ .irq_mask = its_mask_msi_irq,
+ .irq_eoi = irq_chip_eoi_parent,
+};
+
+static int its_pci_msi_vec_count(struct pci_dev *pdev, void *data)
+{
+ int msi, msix, *count = data;
+
+ msi = max(pci_msi_vec_count(pdev), 0);
+ msix = max(pci_msix_vec_count(pdev), 0);
+ *count += max(msi, msix);
+
+ return 0;
+}
+
+static int its_get_pci_alias(struct pci_dev *pdev, u16 alias, void *data)
+{
+ struct pci_dev **alias_dev = data;
+
+ *alias_dev = pdev;
+
+ return 0;
+}
+
+static int its_pci_msi_prepare(struct irq_domain *domain, struct device *dev,
+ int nvec, msi_alloc_info_t *info)
+{
+ struct pci_dev *pdev, *alias_dev;
+ struct msi_domain_info *msi_info;
+ int alias_count = 0, minnvec = 1;
+
+ if (!dev_is_pci(dev))
+ return -EINVAL;
+
+ msi_info = msi_get_domain_info(domain->parent);
+
+ pdev = to_pci_dev(dev);
+ /*
+ * If pdev is downstream of any aliasing bridges, take an upper
+ * bound of how many other vectors could map to the same DevID.
+ * Also tell the ITS that the signalling will come from a proxy
+ * device, and that special allocation rules apply.
+ */
+ pci_for_each_dma_alias(pdev, its_get_pci_alias, &alias_dev);
+ if (alias_dev != pdev) {
+ if (alias_dev->subordinate)
+ pci_walk_bus(alias_dev->subordinate,
+ its_pci_msi_vec_count, &alias_count);
+ info->flags |= MSI_ALLOC_FLAGS_PROXY_DEVICE;
+ }
+
+ /* ITS specific DeviceID, as the core ITS ignores dev. */
+ info->scratchpad[0].ul = pci_msi_domain_get_msi_rid(domain, pdev);
+
+ /*
+ * Always allocate a power of 2, and special case device 0 for
+ * broken systems where the DevID is not wired (and all devices
+ * appear as DevID 0). For that reason, we generously allocate a
+ * minimum of 32 MSIs for DevID 0. If you want more because all
+ * your devices are aliasing to DevID 0, consider fixing your HW.
+ */
+ nvec = max(nvec, alias_count);
+ if (!info->scratchpad[0].ul)
+ minnvec = 32;
+ nvec = max_t(int, minnvec, roundup_pow_of_two(nvec));
+ return msi_info->ops->msi_prepare(domain->parent, dev, nvec, info);
+}
+
+static struct msi_domain_ops its_pci_msi_ops = {
+ .msi_prepare = its_pci_msi_prepare,
+};
+
+static struct msi_domain_info its_pci_msi_domain_info = {
+ .flags = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
+ MSI_FLAG_MULTI_PCI_MSI | MSI_FLAG_PCI_MSIX),
+ .ops = &its_pci_msi_ops,
+ .chip = &its_msi_irq_chip,
+};
+
+static struct of_device_id its_device_id[] = {
+ { .compatible = "arm,gic-v3-its", },
+ {},
+};
+
+static int __init its_pci_msi_init_one(struct fwnode_handle *handle,
+ const char *name)
+{
+ struct irq_domain *parent;
+
+ parent = irq_find_matching_fwnode(handle, DOMAIN_BUS_NEXUS);
+ if (!parent || !msi_get_domain_info(parent)) {
+ pr_err("%s: Unable to locate ITS domain\n", name);
+ return -ENXIO;
+ }
+
+ if (!pci_msi_create_irq_domain(handle, &its_pci_msi_domain_info,
+ parent)) {
+ pr_err("%s: Unable to create PCI domain\n", name);
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+static int __init its_pci_of_msi_init(void)
+{
+ struct device_node *np;
+
+ for (np = of_find_matching_node(NULL, its_device_id); np;
+ np = of_find_matching_node(np, its_device_id)) {
+ if (!of_device_is_available(np))
+ continue;
+ if (!of_property_read_bool(np, "msi-controller"))
+ continue;
+
+ if (its_pci_msi_init_one(of_node_to_fwnode(np), np->full_name))
+ continue;
+
+ pr_info("PCI/MSI: %pOF domain created\n", np);
+ }
+
+ return 0;
+}
+
+#ifdef CONFIG_ACPI
+
+static int __init
+its_pci_msi_parse_madt(union acpi_subtable_headers *header,
+ const unsigned long end)
+{
+ struct acpi_madt_generic_translator *its_entry;
+ struct fwnode_handle *dom_handle;
+ const char *node_name;
+ int err = -ENXIO;
+
+ its_entry = (struct acpi_madt_generic_translator *)header;
+ node_name = kasprintf(GFP_KERNEL, "ITS@0x%lx",
+ (long)its_entry->base_address);
+ dom_handle = iort_find_domain_token(its_entry->translation_id);
+ if (!dom_handle) {
+ pr_err("%s: Unable to locate ITS domain handle\n", node_name);
+ goto out;
+ }
+
+ err = its_pci_msi_init_one(dom_handle, node_name);
+ if (!err)
+ pr_info("PCI/MSI: %s domain created\n", node_name);
+
+out:
+ kfree(node_name);
+ return err;
+}
+
+static int __init its_pci_acpi_msi_init(void)
+{
+ acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_TRANSLATOR,
+ its_pci_msi_parse_madt, 0);
+ return 0;
+}
+#else
+static int __init its_pci_acpi_msi_init(void)
+{
+ return 0;
+}
+#endif
+
+static int __init its_pci_msi_init(void)
+{
+ its_pci_of_msi_init();
+ its_pci_acpi_msi_init();
+
+ return 0;
+}
+early_initcall(its_pci_msi_init);