1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Altera PCIe MSI support 4 * 5 * Author: Ley Foon Tan <lftan@altera.com> 6 * 7 * Copyright Altera Corporation (C) 2013-2015. All rights reserved 8 */ 9 10 #include <linux/interrupt.h> 11 #include <linux/irqchip/chained_irq.h> 12 #include <linux/init.h> 13 #include <linux/module.h> 14 #include <linux/msi.h> 15 #include <linux/of_address.h> 16 #include <linux/of_irq.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 0x0 23 #define MSI_ERROR 0x4 24 #define MSI_INTMASK 0x8 25 26 #define MAX_MSI_VECTORS 32 27 28 struct 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 41 static 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 47 static inline u32 msi_readl(struct altera_msi *msi, const u32 reg) 48 { 49 return readl_relaxed(msi->csr_base + reg); 50 } 51 52 static 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 u32 virq; 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 virq = irq_find_mapping(msi->inner_domain, bit); 69 if (virq) 70 generic_handle_irq(virq); 71 else 72 dev_err(&msi->pdev->dev, "unexpected MSI\n"); 73 } 74 } 75 76 chained_irq_exit(chip, desc); 77 } 78 79 static struct irq_chip altera_msi_irq_chip = { 80 .name = "Altera PCIe MSI", 81 .irq_mask = pci_msi_mask_irq, 82 .irq_unmask = pci_msi_unmask_irq, 83 }; 84 85 static struct msi_domain_info altera_msi_domain_info = { 86 .flags = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS | 87 MSI_FLAG_PCI_MSIX), 88 .chip = &altera_msi_irq_chip, 89 }; 90 91 static void altera_compose_msi_msg(struct irq_data *data, struct msi_msg *msg) 92 { 93 struct altera_msi *msi = irq_data_get_irq_chip_data(data); 94 phys_addr_t addr = msi->vector_phy + (data->hwirq * sizeof(u32)); 95 96 msg->address_lo = lower_32_bits(addr); 97 msg->address_hi = upper_32_bits(addr); 98 msg->data = data->hwirq; 99 100 dev_dbg(&msi->pdev->dev, "msi#%d address_hi %#x address_lo %#x\n", 101 (int)data->hwirq, msg->address_hi, msg->address_lo); 102 } 103 104 static int altera_msi_set_affinity(struct irq_data *irq_data, 105 const struct cpumask *mask, bool force) 106 { 107 return -EINVAL; 108 } 109 110 static struct irq_chip altera_msi_bottom_irq_chip = { 111 .name = "Altera MSI", 112 .irq_compose_msi_msg = altera_compose_msi_msg, 113 .irq_set_affinity = altera_msi_set_affinity, 114 }; 115 116 static int altera_irq_domain_alloc(struct irq_domain *domain, unsigned int virq, 117 unsigned int nr_irqs, void *args) 118 { 119 struct altera_msi *msi = domain->host_data; 120 unsigned long bit; 121 u32 mask; 122 123 WARN_ON(nr_irqs != 1); 124 mutex_lock(&msi->lock); 125 126 bit = find_first_zero_bit(msi->used, msi->num_of_vectors); 127 if (bit >= msi->num_of_vectors) { 128 mutex_unlock(&msi->lock); 129 return -ENOSPC; 130 } 131 132 set_bit(bit, msi->used); 133 134 mutex_unlock(&msi->lock); 135 136 irq_domain_set_info(domain, virq, bit, &altera_msi_bottom_irq_chip, 137 domain->host_data, handle_simple_irq, 138 NULL, NULL); 139 140 mask = msi_readl(msi, MSI_INTMASK); 141 mask |= 1 << bit; 142 msi_writel(msi, mask, MSI_INTMASK); 143 144 return 0; 145 } 146 147 static void altera_irq_domain_free(struct irq_domain *domain, 148 unsigned int virq, unsigned int nr_irqs) 149 { 150 struct irq_data *d = irq_domain_get_irq_data(domain, virq); 151 struct altera_msi *msi = irq_data_get_irq_chip_data(d); 152 u32 mask; 153 154 mutex_lock(&msi->lock); 155 156 if (!test_bit(d->hwirq, msi->used)) { 157 dev_err(&msi->pdev->dev, "trying to free unused MSI#%lu\n", 158 d->hwirq); 159 } else { 160 __clear_bit(d->hwirq, msi->used); 161 mask = msi_readl(msi, MSI_INTMASK); 162 mask &= ~(1 << d->hwirq); 163 msi_writel(msi, mask, MSI_INTMASK); 164 } 165 166 mutex_unlock(&msi->lock); 167 } 168 169 static const struct irq_domain_ops msi_domain_ops = { 170 .alloc = altera_irq_domain_alloc, 171 .free = altera_irq_domain_free, 172 }; 173 174 static int altera_allocate_domains(struct altera_msi *msi) 175 { 176 struct fwnode_handle *fwnode = of_node_to_fwnode(msi->pdev->dev.of_node); 177 178 msi->inner_domain = irq_domain_add_linear(NULL, msi->num_of_vectors, 179 &msi_domain_ops, msi); 180 if (!msi->inner_domain) { 181 dev_err(&msi->pdev->dev, "failed to create IRQ domain\n"); 182 return -ENOMEM; 183 } 184 185 msi->msi_domain = pci_msi_create_irq_domain(fwnode, 186 &altera_msi_domain_info, msi->inner_domain); 187 if (!msi->msi_domain) { 188 dev_err(&msi->pdev->dev, "failed to create MSI domain\n"); 189 irq_domain_remove(msi->inner_domain); 190 return -ENOMEM; 191 } 192 193 return 0; 194 } 195 196 static void altera_free_domains(struct altera_msi *msi) 197 { 198 irq_domain_remove(msi->msi_domain); 199 irq_domain_remove(msi->inner_domain); 200 } 201 202 static int altera_msi_remove(struct platform_device *pdev) 203 { 204 struct altera_msi *msi = platform_get_drvdata(pdev); 205 206 msi_writel(msi, 0, MSI_INTMASK); 207 irq_set_chained_handler_and_data(msi->irq, NULL, NULL); 208 209 altera_free_domains(msi); 210 211 platform_set_drvdata(pdev, NULL); 212 return 0; 213 } 214 215 static int altera_msi_probe(struct platform_device *pdev) 216 { 217 struct altera_msi *msi; 218 struct device_node *np = pdev->dev.of_node; 219 struct resource *res; 220 int ret; 221 222 msi = devm_kzalloc(&pdev->dev, sizeof(struct altera_msi), 223 GFP_KERNEL); 224 if (!msi) 225 return -ENOMEM; 226 227 mutex_init(&msi->lock); 228 msi->pdev = pdev; 229 230 msi->csr_base = devm_platform_ioremap_resource_byname(pdev, "csr"); 231 if (IS_ERR(msi->csr_base)) { 232 dev_err(&pdev->dev, "failed to map csr memory\n"); 233 return PTR_ERR(msi->csr_base); 234 } 235 236 res = platform_get_resource_byname(pdev, IORESOURCE_MEM, 237 "vector_slave"); 238 msi->vector_base = devm_ioremap_resource(&pdev->dev, res); 239 if (IS_ERR(msi->vector_base)) 240 return PTR_ERR(msi->vector_base); 241 242 msi->vector_phy = res->start; 243 244 if (of_property_read_u32(np, "num-vectors", &msi->num_of_vectors)) { 245 dev_err(&pdev->dev, "failed to parse the number of vectors\n"); 246 return -EINVAL; 247 } 248 249 ret = altera_allocate_domains(msi); 250 if (ret) 251 return ret; 252 253 msi->irq = platform_get_irq(pdev, 0); 254 if (msi->irq < 0) { 255 ret = msi->irq; 256 goto err; 257 } 258 259 irq_set_chained_handler_and_data(msi->irq, altera_msi_isr, msi); 260 platform_set_drvdata(pdev, msi); 261 262 return 0; 263 264 err: 265 altera_msi_remove(pdev); 266 return ret; 267 } 268 269 static const struct of_device_id altera_msi_of_match[] = { 270 { .compatible = "altr,msi-1.0", NULL }, 271 { }, 272 }; 273 274 static struct platform_driver altera_msi_driver = { 275 .driver = { 276 .name = "altera-msi", 277 .of_match_table = altera_msi_of_match, 278 }, 279 .probe = altera_msi_probe, 280 .remove = altera_msi_remove, 281 }; 282 283 static int __init altera_msi_init(void) 284 { 285 return platform_driver_register(&altera_msi_driver); 286 } 287 288 static void __exit altera_msi_exit(void) 289 { 290 platform_driver_unregister(&altera_msi_driver); 291 } 292 293 subsys_initcall(altera_msi_init); 294 MODULE_DEVICE_TABLE(of, altera_msi_of_match); 295 module_exit(altera_msi_exit); 296 MODULE_LICENSE("GPL v2"); 297