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// 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,
.irq_write_msi_msg = pci_msi_domain_write_msg,
};
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);
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