1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * MSI framework for platform devices 4 * 5 * Copyright (C) 2015 ARM Limited, All Rights Reserved. 6 * Author: Marc Zyngier <marc.zyngier@arm.com> 7 */ 8 9 #include <linux/device.h> 10 #include <linux/idr.h> 11 #include <linux/irq.h> 12 #include <linux/irqdomain.h> 13 #include <linux/msi.h> 14 #include <linux/slab.h> 15 16 #define DEV_ID_SHIFT 21 17 #define MAX_DEV_MSIS (1 << (32 - DEV_ID_SHIFT)) 18 19 /* 20 * Internal data structure containing a (made up, but unique) devid 21 * and the callback to write the MSI message. 22 */ 23 struct platform_msi_priv_data { 24 struct device *dev; 25 void *host_data; 26 msi_alloc_info_t arg; 27 irq_write_msi_msg_t write_msg; 28 int devid; 29 }; 30 31 /* The devid allocator */ 32 static DEFINE_IDA(platform_msi_devid_ida); 33 34 #ifdef GENERIC_MSI_DOMAIN_OPS 35 /* 36 * Convert an msi_desc to a globaly unique identifier (per-device 37 * devid + msi_desc position in the msi_list). 38 */ 39 static irq_hw_number_t platform_msi_calc_hwirq(struct msi_desc *desc) 40 { 41 u32 devid; 42 43 devid = desc->platform.msi_priv_data->devid; 44 45 return (devid << (32 - DEV_ID_SHIFT)) | desc->platform.msi_index; 46 } 47 48 static void platform_msi_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc) 49 { 50 arg->desc = desc; 51 arg->hwirq = platform_msi_calc_hwirq(desc); 52 } 53 54 static int platform_msi_init(struct irq_domain *domain, 55 struct msi_domain_info *info, 56 unsigned int virq, irq_hw_number_t hwirq, 57 msi_alloc_info_t *arg) 58 { 59 return irq_domain_set_hwirq_and_chip(domain, virq, hwirq, 60 info->chip, info->chip_data); 61 } 62 #else 63 #define platform_msi_set_desc NULL 64 #define platform_msi_init NULL 65 #endif 66 67 static void platform_msi_update_dom_ops(struct msi_domain_info *info) 68 { 69 struct msi_domain_ops *ops = info->ops; 70 71 BUG_ON(!ops); 72 73 if (ops->msi_init == NULL) 74 ops->msi_init = platform_msi_init; 75 if (ops->set_desc == NULL) 76 ops->set_desc = platform_msi_set_desc; 77 } 78 79 static void platform_msi_write_msg(struct irq_data *data, struct msi_msg *msg) 80 { 81 struct msi_desc *desc = irq_data_get_msi_desc(data); 82 struct platform_msi_priv_data *priv_data; 83 84 priv_data = desc->platform.msi_priv_data; 85 86 priv_data->write_msg(desc, msg); 87 } 88 89 static void platform_msi_update_chip_ops(struct msi_domain_info *info) 90 { 91 struct irq_chip *chip = info->chip; 92 93 BUG_ON(!chip); 94 if (!chip->irq_mask) 95 chip->irq_mask = irq_chip_mask_parent; 96 if (!chip->irq_unmask) 97 chip->irq_unmask = irq_chip_unmask_parent; 98 if (!chip->irq_eoi) 99 chip->irq_eoi = irq_chip_eoi_parent; 100 if (!chip->irq_set_affinity) 101 chip->irq_set_affinity = msi_domain_set_affinity; 102 if (!chip->irq_write_msi_msg) 103 chip->irq_write_msi_msg = platform_msi_write_msg; 104 if (WARN_ON((info->flags & MSI_FLAG_LEVEL_CAPABLE) && 105 !(chip->flags & IRQCHIP_SUPPORTS_LEVEL_MSI))) 106 info->flags &= ~MSI_FLAG_LEVEL_CAPABLE; 107 } 108 109 static void platform_msi_free_descs(struct device *dev, int base, int nvec) 110 { 111 struct msi_desc *desc, *tmp; 112 113 list_for_each_entry_safe(desc, tmp, dev_to_msi_list(dev), list) { 114 if (desc->platform.msi_index >= base && 115 desc->platform.msi_index < (base + nvec)) { 116 list_del(&desc->list); 117 free_msi_entry(desc); 118 } 119 } 120 } 121 122 static int platform_msi_alloc_descs_with_irq(struct device *dev, int virq, 123 int nvec, 124 struct platform_msi_priv_data *data) 125 126 { 127 struct msi_desc *desc; 128 int i, base = 0; 129 130 if (!list_empty(dev_to_msi_list(dev))) { 131 desc = list_last_entry(dev_to_msi_list(dev), 132 struct msi_desc, list); 133 base = desc->platform.msi_index + 1; 134 } 135 136 for (i = 0; i < nvec; i++) { 137 desc = alloc_msi_entry(dev, 1, NULL); 138 if (!desc) 139 break; 140 141 desc->platform.msi_priv_data = data; 142 desc->platform.msi_index = base + i; 143 desc->irq = virq ? virq + i : 0; 144 145 list_add_tail(&desc->list, dev_to_msi_list(dev)); 146 } 147 148 if (i != nvec) { 149 /* Clean up the mess */ 150 platform_msi_free_descs(dev, base, nvec); 151 152 return -ENOMEM; 153 } 154 155 return 0; 156 } 157 158 static int platform_msi_alloc_descs(struct device *dev, int nvec, 159 struct platform_msi_priv_data *data) 160 161 { 162 return platform_msi_alloc_descs_with_irq(dev, 0, nvec, data); 163 } 164 165 /** 166 * platform_msi_create_irq_domain - Create a platform MSI interrupt domain 167 * @fwnode: Optional fwnode of the interrupt controller 168 * @info: MSI domain info 169 * @parent: Parent irq domain 170 * 171 * Updates the domain and chip ops and creates a platform MSI 172 * interrupt domain. 173 * 174 * Returns: 175 * A domain pointer or NULL in case of failure. 176 */ 177 struct irq_domain *platform_msi_create_irq_domain(struct fwnode_handle *fwnode, 178 struct msi_domain_info *info, 179 struct irq_domain *parent) 180 { 181 struct irq_domain *domain; 182 183 if (info->flags & MSI_FLAG_USE_DEF_DOM_OPS) 184 platform_msi_update_dom_ops(info); 185 if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS) 186 platform_msi_update_chip_ops(info); 187 188 domain = msi_create_irq_domain(fwnode, info, parent); 189 if (domain) 190 irq_domain_update_bus_token(domain, DOMAIN_BUS_PLATFORM_MSI); 191 192 return domain; 193 } 194 195 static struct platform_msi_priv_data * 196 platform_msi_alloc_priv_data(struct device *dev, unsigned int nvec, 197 irq_write_msi_msg_t write_msi_msg) 198 { 199 struct platform_msi_priv_data *datap; 200 /* 201 * Limit the number of interrupts to 2048 per device. Should we 202 * need to bump this up, DEV_ID_SHIFT should be adjusted 203 * accordingly (which would impact the max number of MSI 204 * capable devices). 205 */ 206 if (!dev->msi_domain || !write_msi_msg || !nvec || nvec > MAX_DEV_MSIS) 207 return ERR_PTR(-EINVAL); 208 209 if (dev->msi_domain->bus_token != DOMAIN_BUS_PLATFORM_MSI) { 210 dev_err(dev, "Incompatible msi_domain, giving up\n"); 211 return ERR_PTR(-EINVAL); 212 } 213 214 /* Already had a helping of MSI? Greed... */ 215 if (!list_empty(dev_to_msi_list(dev))) 216 return ERR_PTR(-EBUSY); 217 218 datap = kzalloc(sizeof(*datap), GFP_KERNEL); 219 if (!datap) 220 return ERR_PTR(-ENOMEM); 221 222 datap->devid = ida_simple_get(&platform_msi_devid_ida, 223 0, 1 << DEV_ID_SHIFT, GFP_KERNEL); 224 if (datap->devid < 0) { 225 int err = datap->devid; 226 kfree(datap); 227 return ERR_PTR(err); 228 } 229 230 datap->write_msg = write_msi_msg; 231 datap->dev = dev; 232 233 return datap; 234 } 235 236 static void platform_msi_free_priv_data(struct platform_msi_priv_data *data) 237 { 238 ida_simple_remove(&platform_msi_devid_ida, data->devid); 239 kfree(data); 240 } 241 242 /** 243 * platform_msi_domain_alloc_irqs - Allocate MSI interrupts for @dev 244 * @dev: The device for which to allocate interrupts 245 * @nvec: The number of interrupts to allocate 246 * @write_msi_msg: Callback to write an interrupt message for @dev 247 * 248 * Returns: 249 * Zero for success, or an error code in case of failure 250 */ 251 int platform_msi_domain_alloc_irqs(struct device *dev, unsigned int nvec, 252 irq_write_msi_msg_t write_msi_msg) 253 { 254 struct platform_msi_priv_data *priv_data; 255 int err; 256 257 priv_data = platform_msi_alloc_priv_data(dev, nvec, write_msi_msg); 258 if (IS_ERR(priv_data)) 259 return PTR_ERR(priv_data); 260 261 err = platform_msi_alloc_descs(dev, nvec, priv_data); 262 if (err) 263 goto out_free_priv_data; 264 265 err = msi_domain_alloc_irqs(dev->msi_domain, dev, nvec); 266 if (err) 267 goto out_free_desc; 268 269 return 0; 270 271 out_free_desc: 272 platform_msi_free_descs(dev, 0, nvec); 273 out_free_priv_data: 274 platform_msi_free_priv_data(priv_data); 275 276 return err; 277 } 278 EXPORT_SYMBOL_GPL(platform_msi_domain_alloc_irqs); 279 280 /** 281 * platform_msi_domain_free_irqs - Free MSI interrupts for @dev 282 * @dev: The device for which to free interrupts 283 */ 284 void platform_msi_domain_free_irqs(struct device *dev) 285 { 286 if (!list_empty(dev_to_msi_list(dev))) { 287 struct msi_desc *desc; 288 289 desc = first_msi_entry(dev); 290 platform_msi_free_priv_data(desc->platform.msi_priv_data); 291 } 292 293 msi_domain_free_irqs(dev->msi_domain, dev); 294 platform_msi_free_descs(dev, 0, MAX_DEV_MSIS); 295 } 296 EXPORT_SYMBOL_GPL(platform_msi_domain_free_irqs); 297 298 /** 299 * platform_msi_get_host_data - Query the private data associated with 300 * a platform-msi domain 301 * @domain: The platform-msi domain 302 * 303 * Returns the private data provided when calling 304 * platform_msi_create_device_domain. 305 */ 306 void *platform_msi_get_host_data(struct irq_domain *domain) 307 { 308 struct platform_msi_priv_data *data = domain->host_data; 309 return data->host_data; 310 } 311 312 /** 313 * platform_msi_create_device_domain - Create a platform-msi domain 314 * 315 * @dev: The device generating the MSIs 316 * @nvec: The number of MSIs that need to be allocated 317 * @write_msi_msg: Callback to write an interrupt message for @dev 318 * @ops: The hierarchy domain operations to use 319 * @host_data: Private data associated to this domain 320 * 321 * Returns an irqdomain for @nvec interrupts 322 */ 323 struct irq_domain * 324 __platform_msi_create_device_domain(struct device *dev, 325 unsigned int nvec, 326 bool is_tree, 327 irq_write_msi_msg_t write_msi_msg, 328 const struct irq_domain_ops *ops, 329 void *host_data) 330 { 331 struct platform_msi_priv_data *data; 332 struct irq_domain *domain; 333 int err; 334 335 data = platform_msi_alloc_priv_data(dev, nvec, write_msi_msg); 336 if (IS_ERR(data)) 337 return NULL; 338 339 data->host_data = host_data; 340 domain = irq_domain_create_hierarchy(dev->msi_domain, 0, 341 is_tree ? 0 : nvec, 342 dev->fwnode, ops, data); 343 if (!domain) 344 goto free_priv; 345 346 err = msi_domain_prepare_irqs(domain->parent, dev, nvec, &data->arg); 347 if (err) 348 goto free_domain; 349 350 return domain; 351 352 free_domain: 353 irq_domain_remove(domain); 354 free_priv: 355 platform_msi_free_priv_data(data); 356 return NULL; 357 } 358 359 /** 360 * platform_msi_domain_free - Free interrupts associated with a platform-msi 361 * domain 362 * 363 * @domain: The platform-msi domain 364 * @virq: The base irq from which to perform the free operation 365 * @nvec: How many interrupts to free from @virq 366 */ 367 void platform_msi_domain_free(struct irq_domain *domain, unsigned int virq, 368 unsigned int nvec) 369 { 370 struct platform_msi_priv_data *data = domain->host_data; 371 struct msi_desc *desc, *tmp; 372 for_each_msi_entry_safe(desc, tmp, data->dev) { 373 if (WARN_ON(!desc->irq || desc->nvec_used != 1)) 374 return; 375 if (!(desc->irq >= virq && desc->irq < (virq + nvec))) 376 continue; 377 378 irq_domain_free_irqs_common(domain, desc->irq, 1); 379 list_del(&desc->list); 380 free_msi_entry(desc); 381 } 382 } 383 384 /** 385 * platform_msi_domain_alloc - Allocate interrupts associated with 386 * a platform-msi domain 387 * 388 * @domain: The platform-msi domain 389 * @virq: The base irq from which to perform the allocate operation 390 * @nvec: How many interrupts to free from @virq 391 * 392 * Return 0 on success, or an error code on failure. Must be called 393 * with irq_domain_mutex held (which can only be done as part of a 394 * top-level interrupt allocation). 395 */ 396 int platform_msi_domain_alloc(struct irq_domain *domain, unsigned int virq, 397 unsigned int nr_irqs) 398 { 399 struct platform_msi_priv_data *data = domain->host_data; 400 int err; 401 402 err = platform_msi_alloc_descs_with_irq(data->dev, virq, nr_irqs, data); 403 if (err) 404 return err; 405 406 err = msi_domain_populate_irqs(domain->parent, data->dev, 407 virq, nr_irqs, &data->arg); 408 if (err) 409 platform_msi_domain_free(domain, virq, nr_irqs); 410 411 return err; 412 } 413