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 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 77 static 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 83 static 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_PCI_MSIX), 86 .chip = &altera_msi_irq_chip, 87 }; 88 89 static 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 } 101 102 static int altera_msi_set_affinity(struct irq_data *irq_data, 103 const struct cpumask *mask, bool force) 104 { 105 return -EINVAL; 106 } 107 108 static struct irq_chip altera_msi_bottom_irq_chip = { 109 .name = "Altera MSI", 110 .irq_compose_msi_msg = altera_compose_msi_msg, 111 .irq_set_affinity = altera_msi_set_affinity, 112 }; 113 114 static int altera_irq_domain_alloc(struct irq_domain *domain, unsigned int virq, 115 unsigned int nr_irqs, void *args) 116 { 117 struct altera_msi *msi = domain->host_data; 118 unsigned long bit; 119 u32 mask; 120 121 WARN_ON(nr_irqs != 1); 122 mutex_lock(&msi->lock); 123 124 bit = find_first_zero_bit(msi->used, msi->num_of_vectors); 125 if (bit >= msi->num_of_vectors) { 126 mutex_unlock(&msi->lock); 127 return -ENOSPC; 128 } 129 130 set_bit(bit, msi->used); 131 132 mutex_unlock(&msi->lock); 133 134 irq_domain_set_info(domain, virq, bit, &altera_msi_bottom_irq_chip, 135 domain->host_data, handle_simple_irq, 136 NULL, NULL); 137 138 mask = msi_readl(msi, MSI_INTMASK); 139 mask |= 1 << bit; 140 msi_writel(msi, mask, MSI_INTMASK); 141 142 return 0; 143 } 144 145 static void altera_irq_domain_free(struct irq_domain *domain, 146 unsigned int virq, unsigned int nr_irqs) 147 { 148 struct irq_data *d = irq_domain_get_irq_data(domain, virq); 149 struct altera_msi *msi = irq_data_get_irq_chip_data(d); 150 u32 mask; 151 152 mutex_lock(&msi->lock); 153 154 if (!test_bit(d->hwirq, msi->used)) { 155 dev_err(&msi->pdev->dev, "trying to free unused MSI#%lu\n", 156 d->hwirq); 157 } else { 158 __clear_bit(d->hwirq, msi->used); 159 mask = msi_readl(msi, MSI_INTMASK); 160 mask &= ~(1 << d->hwirq); 161 msi_writel(msi, mask, MSI_INTMASK); 162 } 163 164 mutex_unlock(&msi->lock); 165 } 166 167 static const struct irq_domain_ops msi_domain_ops = { 168 .alloc = altera_irq_domain_alloc, 169 .free = altera_irq_domain_free, 170 }; 171 172 static int altera_allocate_domains(struct altera_msi *msi) 173 { 174 struct fwnode_handle *fwnode = of_node_to_fwnode(msi->pdev->dev.of_node); 175 176 msi->inner_domain = irq_domain_add_linear(NULL, msi->num_of_vectors, 177 &msi_domain_ops, msi); 178 if (!msi->inner_domain) { 179 dev_err(&msi->pdev->dev, "failed to create IRQ domain\n"); 180 return -ENOMEM; 181 } 182 183 msi->msi_domain = pci_msi_create_irq_domain(fwnode, 184 &altera_msi_domain_info, msi->inner_domain); 185 if (!msi->msi_domain) { 186 dev_err(&msi->pdev->dev, "failed to create MSI domain\n"); 187 irq_domain_remove(msi->inner_domain); 188 return -ENOMEM; 189 } 190 191 return 0; 192 } 193 194 static void altera_free_domains(struct altera_msi *msi) 195 { 196 irq_domain_remove(msi->msi_domain); 197 irq_domain_remove(msi->inner_domain); 198 } 199 200 static int altera_msi_remove(struct platform_device *pdev) 201 { 202 struct altera_msi *msi = platform_get_drvdata(pdev); 203 204 msi_writel(msi, 0, MSI_INTMASK); 205 irq_set_chained_handler_and_data(msi->irq, NULL, NULL); 206 207 altera_free_domains(msi); 208 209 platform_set_drvdata(pdev, NULL); 210 return 0; 211 } 212 213 static int altera_msi_probe(struct platform_device *pdev) 214 { 215 struct altera_msi *msi; 216 struct device_node *np = pdev->dev.of_node; 217 struct resource *res; 218 int ret; 219 220 msi = devm_kzalloc(&pdev->dev, sizeof(struct altera_msi), 221 GFP_KERNEL); 222 if (!msi) 223 return -ENOMEM; 224 225 mutex_init(&msi->lock); 226 msi->pdev = pdev; 227 228 msi->csr_base = devm_platform_ioremap_resource_byname(pdev, "csr"); 229 if (IS_ERR(msi->csr_base)) { 230 dev_err(&pdev->dev, "failed to map csr memory\n"); 231 return PTR_ERR(msi->csr_base); 232 } 233 234 res = platform_get_resource_byname(pdev, IORESOURCE_MEM, 235 "vector_slave"); 236 msi->vector_base = devm_ioremap_resource(&pdev->dev, res); 237 if (IS_ERR(msi->vector_base)) 238 return PTR_ERR(msi->vector_base); 239 240 msi->vector_phy = res->start; 241 242 if (of_property_read_u32(np, "num-vectors", &msi->num_of_vectors)) { 243 dev_err(&pdev->dev, "failed to parse the number of vectors\n"); 244 return -EINVAL; 245 } 246 247 ret = altera_allocate_domains(msi); 248 if (ret) 249 return ret; 250 251 msi->irq = platform_get_irq(pdev, 0); 252 if (msi->irq < 0) { 253 ret = msi->irq; 254 goto err; 255 } 256 257 irq_set_chained_handler_and_data(msi->irq, altera_msi_isr, msi); 258 platform_set_drvdata(pdev, msi); 259 260 return 0; 261 262 err: 263 altera_msi_remove(pdev); 264 return ret; 265 } 266 267 static const struct of_device_id altera_msi_of_match[] = { 268 { .compatible = "altr,msi-1.0", NULL }, 269 { }, 270 }; 271 272 static struct platform_driver altera_msi_driver = { 273 .driver = { 274 .name = "altera-msi", 275 .of_match_table = altera_msi_of_match, 276 }, 277 .probe = altera_msi_probe, 278 .remove = altera_msi_remove, 279 }; 280 281 static int __init altera_msi_init(void) 282 { 283 return platform_driver_register(&altera_msi_driver); 284 } 285 286 static void __exit altera_msi_exit(void) 287 { 288 platform_driver_unregister(&altera_msi_driver); 289 } 290 291 subsys_initcall(altera_msi_init); 292 MODULE_DEVICE_TABLE(of, altera_msi_of_match); 293 module_exit(altera_msi_exit); 294 MODULE_LICENSE("GPL v2"); 295