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1// SPDX-License-Identifier: GPL-2.02/*3 * Altera PCIe MSI support4 *5 * Author: Ley Foon Tan <lftan@altera.com>6 *7 * Copyright Altera Corporation (C) 2013-2015. All rights reserved8 */9 10#include <linux/interrupt.h>11#include <linux/irqchip/chained_irq.h>12#include <linux/irqdomain.h>13#include <linux/init.h>14#include <linux/module.h>15#include <linux/msi.h>16#include <linux/of_address.h>17#include <linux/of_pci.h>18#include <linux/pci.h>19#include <linux/platform_device.h>20#include <linux/slab.h>21 22#define MSI_STATUS 0x023#define MSI_ERROR 0x424#define MSI_INTMASK 0x825 26#define MAX_MSI_VECTORS 3227 28struct altera_msi {29 DECLARE_BITMAP(used, MAX_MSI_VECTORS);30 struct mutex lock; /* protect "used" bitmap */31 struct platform_device *pdev;32 struct irq_domain *msi_domain;33 struct irq_domain *inner_domain;34 void __iomem *csr_base;35 void __iomem *vector_base;36 phys_addr_t vector_phy;37 u32 num_of_vectors;38 int irq;39};40 41static inline void msi_writel(struct altera_msi *msi, const u32 value,42 const u32 reg)43{44 writel_relaxed(value, msi->csr_base + reg);45}46 47static inline u32 msi_readl(struct altera_msi *msi, const u32 reg)48{49 return readl_relaxed(msi->csr_base + reg);50}51 52static void altera_msi_isr(struct irq_desc *desc)53{54 struct irq_chip *chip = irq_desc_get_chip(desc);55 struct altera_msi *msi;56 unsigned long status;57 u32 bit;58 int ret;59 60 chained_irq_enter(chip, desc);61 msi = irq_desc_get_handler_data(desc);62 63 while ((status = msi_readl(msi, MSI_STATUS)) != 0) {64 for_each_set_bit(bit, &status, msi->num_of_vectors) {65 /* Dummy read from vector to clear the interrupt */66 readl_relaxed(msi->vector_base + (bit * sizeof(u32)));67 68 ret = generic_handle_domain_irq(msi->inner_domain, bit);69 if (ret)70 dev_err_ratelimited(&msi->pdev->dev, "unexpected MSI\n");71 }72 }73 74 chained_irq_exit(chip, desc);75}76 77static struct irq_chip altera_msi_irq_chip = {78 .name = "Altera PCIe MSI",79 .irq_mask = pci_msi_mask_irq,80 .irq_unmask = pci_msi_unmask_irq,81};82 83static struct msi_domain_info altera_msi_domain_info = {84 .flags = MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |85 MSI_FLAG_NO_AFFINITY | MSI_FLAG_PCI_MSIX,86 .chip = &altera_msi_irq_chip,87};88 89static void altera_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)90{91 struct altera_msi *msi = irq_data_get_irq_chip_data(data);92 phys_addr_t addr = msi->vector_phy + (data->hwirq * sizeof(u32));93 94 msg->address_lo = lower_32_bits(addr);95 msg->address_hi = upper_32_bits(addr);96 msg->data = data->hwirq;97 98 dev_dbg(&msi->pdev->dev, "msi#%d address_hi %#x address_lo %#x\n",99 (int)data->hwirq, msg->address_hi, msg->address_lo);100}101 102static struct irq_chip altera_msi_bottom_irq_chip = {103 .name = "Altera MSI",104 .irq_compose_msi_msg = altera_compose_msi_msg,105};106 107static int altera_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,108 unsigned int nr_irqs, void *args)109{110 struct altera_msi *msi = domain->host_data;111 unsigned long bit;112 u32 mask;113 114 WARN_ON(nr_irqs != 1);115 mutex_lock(&msi->lock);116 117 bit = find_first_zero_bit(msi->used, msi->num_of_vectors);118 if (bit >= msi->num_of_vectors) {119 mutex_unlock(&msi->lock);120 return -ENOSPC;121 }122 123 set_bit(bit, msi->used);124 125 mutex_unlock(&msi->lock);126 127 irq_domain_set_info(domain, virq, bit, &altera_msi_bottom_irq_chip,128 domain->host_data, handle_simple_irq,129 NULL, NULL);130 131 mask = msi_readl(msi, MSI_INTMASK);132 mask |= 1 << bit;133 msi_writel(msi, mask, MSI_INTMASK);134 135 return 0;136}137 138static void altera_irq_domain_free(struct irq_domain *domain,139 unsigned int virq, unsigned int nr_irqs)140{141 struct irq_data *d = irq_domain_get_irq_data(domain, virq);142 struct altera_msi *msi = irq_data_get_irq_chip_data(d);143 u32 mask;144 145 mutex_lock(&msi->lock);146 147 if (!test_bit(d->hwirq, msi->used)) {148 dev_err(&msi->pdev->dev, "trying to free unused MSI#%lu\n",149 d->hwirq);150 } else {151 __clear_bit(d->hwirq, msi->used);152 mask = msi_readl(msi, MSI_INTMASK);153 mask &= ~(1 << d->hwirq);154 msi_writel(msi, mask, MSI_INTMASK);155 }156 157 mutex_unlock(&msi->lock);158}159 160static const struct irq_domain_ops msi_domain_ops = {161 .alloc = altera_irq_domain_alloc,162 .free = altera_irq_domain_free,163};164 165static int altera_allocate_domains(struct altera_msi *msi)166{167 struct fwnode_handle *fwnode = of_node_to_fwnode(msi->pdev->dev.of_node);168 169 msi->inner_domain = irq_domain_add_linear(NULL, msi->num_of_vectors,170 &msi_domain_ops, msi);171 if (!msi->inner_domain) {172 dev_err(&msi->pdev->dev, "failed to create IRQ domain\n");173 return -ENOMEM;174 }175 176 msi->msi_domain = pci_msi_create_irq_domain(fwnode,177 &altera_msi_domain_info, msi->inner_domain);178 if (!msi->msi_domain) {179 dev_err(&msi->pdev->dev, "failed to create MSI domain\n");180 irq_domain_remove(msi->inner_domain);181 return -ENOMEM;182 }183 184 return 0;185}186 187static void altera_free_domains(struct altera_msi *msi)188{189 irq_domain_remove(msi->msi_domain);190 irq_domain_remove(msi->inner_domain);191}192 193static void altera_msi_remove(struct platform_device *pdev)194{195 struct altera_msi *msi = platform_get_drvdata(pdev);196 197 msi_writel(msi, 0, MSI_INTMASK);198 irq_set_chained_handler_and_data(msi->irq, NULL, NULL);199 200 altera_free_domains(msi);201 202 platform_set_drvdata(pdev, NULL);203}204 205static int altera_msi_probe(struct platform_device *pdev)206{207 struct altera_msi *msi;208 struct device_node *np = pdev->dev.of_node;209 struct resource *res;210 int ret;211 212 msi = devm_kzalloc(&pdev->dev, sizeof(struct altera_msi),213 GFP_KERNEL);214 if (!msi)215 return -ENOMEM;216 217 mutex_init(&msi->lock);218 msi->pdev = pdev;219 220 msi->csr_base = devm_platform_ioremap_resource_byname(pdev, "csr");221 if (IS_ERR(msi->csr_base)) {222 dev_err(&pdev->dev, "failed to map csr memory\n");223 return PTR_ERR(msi->csr_base);224 }225 226 res = platform_get_resource_byname(pdev, IORESOURCE_MEM,227 "vector_slave");228 msi->vector_base = devm_ioremap_resource(&pdev->dev, res);229 if (IS_ERR(msi->vector_base))230 return PTR_ERR(msi->vector_base);231 232 msi->vector_phy = res->start;233 234 if (of_property_read_u32(np, "num-vectors", &msi->num_of_vectors)) {235 dev_err(&pdev->dev, "failed to parse the number of vectors\n");236 return -EINVAL;237 }238 239 ret = altera_allocate_domains(msi);240 if (ret)241 return ret;242 243 msi->irq = platform_get_irq(pdev, 0);244 if (msi->irq < 0) {245 ret = msi->irq;246 goto err;247 }248 249 irq_set_chained_handler_and_data(msi->irq, altera_msi_isr, msi);250 platform_set_drvdata(pdev, msi);251 252 return 0;253 254err:255 altera_msi_remove(pdev);256 return ret;257}258 259static const struct of_device_id altera_msi_of_match[] = {260 { .compatible = "altr,msi-1.0", NULL },261 { },262};263 264static struct platform_driver altera_msi_driver = {265 .driver = {266 .name = "altera-msi",267 .of_match_table = altera_msi_of_match,268 },269 .probe = altera_msi_probe,270 .remove_new = altera_msi_remove,271};272 273static int __init altera_msi_init(void)274{275 return platform_driver_register(&altera_msi_driver);276}277 278static void __exit altera_msi_exit(void)279{280 platform_driver_unregister(&altera_msi_driver);281}282 283subsys_initcall(altera_msi_init);284MODULE_DEVICE_TABLE(of, altera_msi_of_match);285module_exit(altera_msi_exit);286MODULE_DESCRIPTION("Altera PCIe MSI support driver");287MODULE_LICENSE("GPL v2");288