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 } 105 106 static void platform_msi_free_descs(struct device *dev, int base, int nvec) 107 { 108 struct msi_desc *desc, *tmp; 109 110 list_for_each_entry_safe(desc, tmp, dev_to_msi_list(dev), list) { 111 if (desc->platform.msi_index >= base && 112 desc->platform.msi_index < (base + nvec)) { 113 list_del(&desc->list); 114 free_msi_entry(desc); 115 } 116 } 117 } 118 119 static int platform_msi_alloc_descs_with_irq(struct device *dev, int virq, 120 int nvec, 121 struct platform_msi_priv_data *data) 122 123 { 124 struct msi_desc *desc; 125 int i, base = 0; 126 127 if (!list_empty(dev_to_msi_list(dev))) { 128 desc = list_last_entry(dev_to_msi_list(dev), 129 struct msi_desc, list); 130 base = desc->platform.msi_index + 1; 131 } 132 133 for (i = 0; i < nvec; i++) { 134 desc = alloc_msi_entry(dev, 1, NULL); 135 if (!desc) 136 break; 137 138 desc->platform.msi_priv_data = data; 139 desc->platform.msi_index = base + i; 140 desc->irq = virq ? virq + i : 0; 141 142 list_add_tail(&desc->list, dev_to_msi_list(dev)); 143 } 144 145 if (i != nvec) { 146 /* Clean up the mess */ 147 platform_msi_free_descs(dev, base, nvec); 148 149 return -ENOMEM; 150 } 151 152 return 0; 153 } 154 155 static int platform_msi_alloc_descs(struct device *dev, int nvec, 156 struct platform_msi_priv_data *data) 157 158 { 159 return platform_msi_alloc_descs_with_irq(dev, 0, nvec, data); 160 } 161 162 /** 163 * platform_msi_create_irq_domain - Create a platform MSI interrupt domain 164 * @fwnode: Optional fwnode of the interrupt controller 165 * @info: MSI domain info 166 * @parent: Parent irq domain 167 * 168 * Updates the domain and chip ops and creates a platform MSI 169 * interrupt domain. 170 * 171 * Returns: 172 * A domain pointer or NULL in case of failure. 173 */ 174 struct irq_domain *platform_msi_create_irq_domain(struct fwnode_handle *fwnode, 175 struct msi_domain_info *info, 176 struct irq_domain *parent) 177 { 178 struct irq_domain *domain; 179 180 if (info->flags & MSI_FLAG_USE_DEF_DOM_OPS) 181 platform_msi_update_dom_ops(info); 182 if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS) 183 platform_msi_update_chip_ops(info); 184 185 domain = msi_create_irq_domain(fwnode, info, parent); 186 if (domain) 187 irq_domain_update_bus_token(domain, DOMAIN_BUS_PLATFORM_MSI); 188 189 return domain; 190 } 191 192 static struct platform_msi_priv_data * 193 platform_msi_alloc_priv_data(struct device *dev, unsigned int nvec, 194 irq_write_msi_msg_t write_msi_msg) 195 { 196 struct platform_msi_priv_data *datap; 197 /* 198 * Limit the number of interrupts to 2048 per device. Should we 199 * need to bump this up, DEV_ID_SHIFT should be adjusted 200 * accordingly (which would impact the max number of MSI 201 * capable devices). 202 */ 203 if (!dev->msi_domain || !write_msi_msg || !nvec || nvec > MAX_DEV_MSIS) 204 return ERR_PTR(-EINVAL); 205 206 if (dev->msi_domain->bus_token != DOMAIN_BUS_PLATFORM_MSI) { 207 dev_err(dev, "Incompatible msi_domain, giving up\n"); 208 return ERR_PTR(-EINVAL); 209 } 210 211 /* Already had a helping of MSI? Greed... */ 212 if (!list_empty(dev_to_msi_list(dev))) 213 return ERR_PTR(-EBUSY); 214 215 datap = kzalloc(sizeof(*datap), GFP_KERNEL); 216 if (!datap) 217 return ERR_PTR(-ENOMEM); 218 219 datap->devid = ida_simple_get(&platform_msi_devid_ida, 220 0, 1 << DEV_ID_SHIFT, GFP_KERNEL); 221 if (datap->devid < 0) { 222 int err = datap->devid; 223 kfree(datap); 224 return ERR_PTR(err); 225 } 226 227 datap->write_msg = write_msi_msg; 228 datap->dev = dev; 229 230 return datap; 231 } 232 233 static void platform_msi_free_priv_data(struct platform_msi_priv_data *data) 234 { 235 ida_simple_remove(&platform_msi_devid_ida, data->devid); 236 kfree(data); 237 } 238 239 /** 240 * platform_msi_domain_alloc_irqs - Allocate MSI interrupts for @dev 241 * @dev: The device for which to allocate interrupts 242 * @nvec: The number of interrupts to allocate 243 * @write_msi_msg: Callback to write an interrupt message for @dev 244 * 245 * Returns: 246 * Zero for success, or an error code in case of failure 247 */ 248 int platform_msi_domain_alloc_irqs(struct device *dev, unsigned int nvec, 249 irq_write_msi_msg_t write_msi_msg) 250 { 251 struct platform_msi_priv_data *priv_data; 252 int err; 253 254 priv_data = platform_msi_alloc_priv_data(dev, nvec, write_msi_msg); 255 if (IS_ERR(priv_data)) 256 return PTR_ERR(priv_data); 257 258 err = platform_msi_alloc_descs(dev, nvec, priv_data); 259 if (err) 260 goto out_free_priv_data; 261 262 err = msi_domain_alloc_irqs(dev->msi_domain, dev, nvec); 263 if (err) 264 goto out_free_desc; 265 266 return 0; 267 268 out_free_desc: 269 platform_msi_free_descs(dev, 0, nvec); 270 out_free_priv_data: 271 platform_msi_free_priv_data(priv_data); 272 273 return err; 274 } 275 EXPORT_SYMBOL_GPL(platform_msi_domain_alloc_irqs); 276 277 /** 278 * platform_msi_domain_free_irqs - Free MSI interrupts for @dev 279 * @dev: The device for which to free interrupts 280 */ 281 void platform_msi_domain_free_irqs(struct device *dev) 282 { 283 if (!list_empty(dev_to_msi_list(dev))) { 284 struct msi_desc *desc; 285 286 desc = first_msi_entry(dev); 287 platform_msi_free_priv_data(desc->platform.msi_priv_data); 288 } 289 290 msi_domain_free_irqs(dev->msi_domain, dev); 291 platform_msi_free_descs(dev, 0, MAX_DEV_MSIS); 292 } 293 EXPORT_SYMBOL_GPL(platform_msi_domain_free_irqs); 294 295 /** 296 * platform_msi_get_host_data - Query the private data associated with 297 * a platform-msi domain 298 * @domain: The platform-msi domain 299 * 300 * Returns the private data provided when calling 301 * platform_msi_create_device_domain. 302 */ 303 void *platform_msi_get_host_data(struct irq_domain *domain) 304 { 305 struct platform_msi_priv_data *data = domain->host_data; 306 return data->host_data; 307 } 308 309 /** 310 * platform_msi_create_device_domain - Create a platform-msi domain 311 * 312 * @dev: The device generating the MSIs 313 * @nvec: The number of MSIs that need to be allocated 314 * @write_msi_msg: Callback to write an interrupt message for @dev 315 * @ops: The hierarchy domain operations to use 316 * @host_data: Private data associated to this domain 317 * 318 * Returns an irqdomain for @nvec interrupts 319 */ 320 struct irq_domain * 321 platform_msi_create_device_domain(struct device *dev, 322 unsigned int nvec, 323 irq_write_msi_msg_t write_msi_msg, 324 const struct irq_domain_ops *ops, 325 void *host_data) 326 { 327 struct platform_msi_priv_data *data; 328 struct irq_domain *domain; 329 int err; 330 331 data = platform_msi_alloc_priv_data(dev, nvec, write_msi_msg); 332 if (IS_ERR(data)) 333 return NULL; 334 335 data->host_data = host_data; 336 domain = irq_domain_create_hierarchy(dev->msi_domain, 0, nvec, 337 dev->fwnode, ops, data); 338 if (!domain) 339 goto free_priv; 340 341 err = msi_domain_prepare_irqs(domain->parent, dev, nvec, &data->arg); 342 if (err) 343 goto free_domain; 344 345 return domain; 346 347 free_domain: 348 irq_domain_remove(domain); 349 free_priv: 350 platform_msi_free_priv_data(data); 351 return NULL; 352 } 353 354 /** 355 * platform_msi_domain_free - Free interrupts associated with a platform-msi 356 * domain 357 * 358 * @domain: The platform-msi domain 359 * @virq: The base irq from which to perform the free operation 360 * @nvec: How many interrupts to free from @virq 361 */ 362 void platform_msi_domain_free(struct irq_domain *domain, unsigned int virq, 363 unsigned int nvec) 364 { 365 struct platform_msi_priv_data *data = domain->host_data; 366 struct msi_desc *desc; 367 for_each_msi_entry(desc, data->dev) { 368 if (WARN_ON(!desc->irq || desc->nvec_used != 1)) 369 return; 370 if (!(desc->irq >= virq && desc->irq < (virq + nvec))) 371 continue; 372 373 irq_domain_free_irqs_common(domain, desc->irq, 1); 374 } 375 } 376 377 /** 378 * platform_msi_domain_alloc - Allocate interrupts associated with 379 * a platform-msi domain 380 * 381 * @domain: The platform-msi domain 382 * @virq: The base irq from which to perform the allocate operation 383 * @nvec: How many interrupts to free from @virq 384 * 385 * Return 0 on success, or an error code on failure. Must be called 386 * with irq_domain_mutex held (which can only be done as part of a 387 * top-level interrupt allocation). 388 */ 389 int platform_msi_domain_alloc(struct irq_domain *domain, unsigned int virq, 390 unsigned int nr_irqs) 391 { 392 struct platform_msi_priv_data *data = domain->host_data; 393 int err; 394 395 err = platform_msi_alloc_descs_with_irq(data->dev, virq, nr_irqs, data); 396 if (err) 397 return err; 398 399 err = msi_domain_populate_irqs(domain->parent, data->dev, 400 virq, nr_irqs, &data->arg); 401 if (err) 402 platform_msi_domain_free(domain, virq, nr_irqs); 403 404 return err; 405 } 406