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// SPDX-License-Identifier: GPL-2.0
/*
* Altera PCIe MSI support
*
* Author: Ley Foon Tan <lftan@altera.com>
*
* Copyright Altera Corporation (C) 2013-2015. All rights reserved
*/
#include <linux/interrupt.h>
#include <linux/irqchip/chained_irq.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/msi.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/of_pci.h>
#include <linux/pci.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#define MSI_STATUS 0x0
#define MSI_ERROR 0x4
#define MSI_INTMASK 0x8
#define MAX_MSI_VECTORS 32
struct altera_msi {
DECLARE_BITMAP(used, MAX_MSI_VECTORS);
struct mutex lock; /* protect "used" bitmap */
struct platform_device *pdev;
struct irq_domain *msi_domain;
struct irq_domain *inner_domain;
void __iomem *csr_base;
void __iomem *vector_base;
phys_addr_t vector_phy;
u32 num_of_vectors;
int irq;
};
static inline void msi_writel(struct altera_msi *msi, const u32 value,
const u32 reg)
{
writel_relaxed(value, msi->csr_base + reg);
}
static inline u32 msi_readl(struct altera_msi *msi, const u32 reg)
{
return readl_relaxed(msi->csr_base + reg);
}
static void altera_msi_isr(struct irq_desc *desc)
{
struct irq_chip *chip = irq_desc_get_chip(desc);
struct altera_msi *msi;
unsigned long status;
u32 bit;
u32 virq;
chained_irq_enter(chip, desc);
msi = irq_desc_get_handler_data(desc);
while ((status = msi_readl(msi, MSI_STATUS)) != 0) {
for_each_set_bit(bit, &status, msi->num_of_vectors) {
/* Dummy read from vector to clear the interrupt */
readl_relaxed(msi->vector_base + (bit * sizeof(u32)));
virq = irq_find_mapping(msi->inner_domain, bit);
if (virq)
generic_handle_irq(virq);
else
dev_err(&msi->pdev->dev, "unexpected MSI\n");
}
}
chained_irq_exit(chip, desc);
}
static struct irq_chip altera_msi_irq_chip = {
.name = "Altera PCIe MSI",
.irq_mask = pci_msi_mask_irq,
.irq_unmask = pci_msi_unmask_irq,
};
static struct msi_domain_info altera_msi_domain_info = {
.flags = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
MSI_FLAG_PCI_MSIX),
.chip = &altera_msi_irq_chip,
};
static void altera_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
{
struct altera_msi *msi = irq_data_get_irq_chip_data(data);
phys_addr_t addr = msi->vector_phy + (data->hwirq * sizeof(u32));
msg->address_lo = lower_32_bits(addr);
msg->address_hi = upper_32_bits(addr);
msg->data = data->hwirq;
dev_dbg(&msi->pdev->dev, "msi#%d address_hi %#x address_lo %#x\n",
(int)data->hwirq, msg->address_hi, msg->address_lo);
}
static int altera_msi_set_affinity(struct irq_data *irq_data,
const struct cpumask *mask, bool force)
{
return -EINVAL;
}
static struct irq_chip altera_msi_bottom_irq_chip = {
.name = "Altera MSI",
.irq_compose_msi_msg = altera_compose_msi_msg,
.irq_set_affinity = altera_msi_set_affinity,
};
static int altera_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
unsigned int nr_irqs, void *args)
{
struct altera_msi *msi = domain->host_data;
unsigned long bit;
u32 mask;
WARN_ON(nr_irqs != 1);
mutex_lock(&msi->lock);
bit = find_first_zero_bit(msi->used, msi->num_of_vectors);
if (bit >= msi->num_of_vectors) {
mutex_unlock(&msi->lock);
return -ENOSPC;
}
set_bit(bit, msi->used);
mutex_unlock(&msi->lock);
irq_domain_set_info(domain, virq, bit, &altera_msi_bottom_irq_chip,
domain->host_data, handle_simple_irq,
NULL, NULL);
mask = msi_readl(msi, MSI_INTMASK);
mask |= 1 << bit;
msi_writel(msi, mask, MSI_INTMASK);
return 0;
}
static void altera_irq_domain_free(struct irq_domain *domain,
unsigned int virq, unsigned int nr_irqs)
{
struct irq_data *d = irq_domain_get_irq_data(domain, virq);
struct altera_msi *msi = irq_data_get_irq_chip_data(d);
u32 mask;
mutex_lock(&msi->lock);
if (!test_bit(d->hwirq, msi->used)) {
dev_err(&msi->pdev->dev, "trying to free unused MSI#%lu\n",
d->hwirq);
} else {
__clear_bit(d->hwirq, msi->used);
mask = msi_readl(msi, MSI_INTMASK);
mask &= ~(1 << d->hwirq);
msi_writel(msi, mask, MSI_INTMASK);
}
mutex_unlock(&msi->lock);
}
static const struct irq_domain_ops msi_domain_ops = {
.alloc = altera_irq_domain_alloc,
.free = altera_irq_domain_free,
};
static int altera_allocate_domains(struct altera_msi *msi)
{
struct fwnode_handle *fwnode = of_node_to_fwnode(msi->pdev->dev.of_node);
msi->inner_domain = irq_domain_add_linear(NULL, msi->num_of_vectors,
&msi_domain_ops, msi);
if (!msi->inner_domain) {
dev_err(&msi->pdev->dev, "failed to create IRQ domain\n");
return -ENOMEM;
}
msi->msi_domain = pci_msi_create_irq_domain(fwnode,
&altera_msi_domain_info, msi->inner_domain);
if (!msi->msi_domain) {
dev_err(&msi->pdev->dev, "failed to create MSI domain\n");
irq_domain_remove(msi->inner_domain);
return -ENOMEM;
}
return 0;
}
static void altera_free_domains(struct altera_msi *msi)
{
irq_domain_remove(msi->msi_domain);
irq_domain_remove(msi->inner_domain);
}
static int altera_msi_remove(struct platform_device *pdev)
{
struct altera_msi *msi = platform_get_drvdata(pdev);
msi_writel(msi, 0, MSI_INTMASK);
irq_set_chained_handler(msi->irq, NULL);
irq_set_handler_data(msi->irq, NULL);
altera_free_domains(msi);
platform_set_drvdata(pdev, NULL);
return 0;
}
static int altera_msi_probe(struct platform_device *pdev)
{
struct altera_msi *msi;
struct device_node *np = pdev->dev.of_node;
struct resource *res;
int ret;
msi = devm_kzalloc(&pdev->dev, sizeof(struct altera_msi),
GFP_KERNEL);
if (!msi)
return -ENOMEM;
mutex_init(&msi->lock);
msi->pdev = pdev;
res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "csr");
msi->csr_base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(msi->csr_base)) {
dev_err(&pdev->dev, "failed to map csr memory\n");
return PTR_ERR(msi->csr_base);
}
res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
"vector_slave");
msi->vector_base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(msi->vector_base)) {
dev_err(&pdev->dev, "failed to map vector_slave memory\n");
return PTR_ERR(msi->vector_base);
}
msi->vector_phy = res->start;
if (of_property_read_u32(np, "num-vectors", &msi->num_of_vectors)) {
dev_err(&pdev->dev, "failed to parse the number of vectors\n");
return -EINVAL;
}
ret = altera_allocate_domains(msi);
if (ret)
return ret;
msi->irq = platform_get_irq(pdev, 0);
if (msi->irq < 0) {
dev_err(&pdev->dev, "failed to map IRQ: %d\n", msi->irq);
ret = msi->irq;
goto err;
}
irq_set_chained_handler_and_data(msi->irq, altera_msi_isr, msi);
platform_set_drvdata(pdev, msi);
return 0;
err:
altera_msi_remove(pdev);
return ret;
}
static const struct of_device_id altera_msi_of_match[] = {
{ .compatible = "altr,msi-1.0", NULL },
{ },
};
static struct platform_driver altera_msi_driver = {
.driver = {
.name = "altera-msi",
.of_match_table = altera_msi_of_match,
},
.probe = altera_msi_probe,
.remove = altera_msi_remove,
};
static int __init altera_msi_init(void)
{
return platform_driver_register(&altera_msi_driver);
}
static void __exit altera_msi_exit(void)
{
platform_driver_unregister(&altera_msi_driver);
}
subsys_initcall(altera_msi_init);
MODULE_DEVICE_TABLE(of, altera_msi_of_match);
module_exit(altera_msi_exit);
MODULE_LICENSE("GPL v2");
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