1 /* 2 * MSI framework for platform devices 3 * 4 * Copyright (C) 2015 ARM Limited, All Rights Reserved. 5 * Author: Marc Zyngier <marc.zyngier@arm.com> 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 as 9 * published by the Free Software Foundation. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program. If not, see <http://www.gnu.org/licenses/>. 18 */ 19 20 #include <linux/device.h> 21 #include <linux/idr.h> 22 #include <linux/irq.h> 23 #include <linux/irqdomain.h> 24 #include <linux/msi.h> 25 #include <linux/slab.h> 26 27 #define DEV_ID_SHIFT 21 28 #define MAX_DEV_MSIS (1 << (32 - DEV_ID_SHIFT)) 29 30 /* 31 * Internal data structure containing a (made up, but unique) devid 32 * and the callback to write the MSI message. 33 */ 34 struct platform_msi_priv_data { 35 struct device *dev; 36 void *host_data; 37 msi_alloc_info_t arg; 38 irq_write_msi_msg_t write_msg; 39 int devid; 40 }; 41 42 /* The devid allocator */ 43 static DEFINE_IDA(platform_msi_devid_ida); 44 45 #ifdef GENERIC_MSI_DOMAIN_OPS 46 /* 47 * Convert an msi_desc to a globaly unique identifier (per-device 48 * devid + msi_desc position in the msi_list). 49 */ 50 static irq_hw_number_t platform_msi_calc_hwirq(struct msi_desc *desc) 51 { 52 u32 devid; 53 54 devid = desc->platform.msi_priv_data->devid; 55 56 return (devid << (32 - DEV_ID_SHIFT)) | desc->platform.msi_index; 57 } 58 59 static void platform_msi_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc) 60 { 61 arg->desc = desc; 62 arg->hwirq = platform_msi_calc_hwirq(desc); 63 } 64 65 static int platform_msi_init(struct irq_domain *domain, 66 struct msi_domain_info *info, 67 unsigned int virq, irq_hw_number_t hwirq, 68 msi_alloc_info_t *arg) 69 { 70 return irq_domain_set_hwirq_and_chip(domain, virq, hwirq, 71 info->chip, info->chip_data); 72 } 73 #else 74 #define platform_msi_set_desc NULL 75 #define platform_msi_init NULL 76 #endif 77 78 static void platform_msi_update_dom_ops(struct msi_domain_info *info) 79 { 80 struct msi_domain_ops *ops = info->ops; 81 82 BUG_ON(!ops); 83 84 if (ops->msi_init == NULL) 85 ops->msi_init = platform_msi_init; 86 if (ops->set_desc == NULL) 87 ops->set_desc = platform_msi_set_desc; 88 } 89 90 static void platform_msi_write_msg(struct irq_data *data, struct msi_msg *msg) 91 { 92 struct msi_desc *desc = irq_data_get_msi_desc(data); 93 struct platform_msi_priv_data *priv_data; 94 95 priv_data = desc->platform.msi_priv_data; 96 97 priv_data->write_msg(desc, msg); 98 } 99 100 static void platform_msi_update_chip_ops(struct msi_domain_info *info) 101 { 102 struct irq_chip *chip = info->chip; 103 104 BUG_ON(!chip); 105 if (!chip->irq_mask) 106 chip->irq_mask = irq_chip_mask_parent; 107 if (!chip->irq_unmask) 108 chip->irq_unmask = irq_chip_unmask_parent; 109 if (!chip->irq_eoi) 110 chip->irq_eoi = irq_chip_eoi_parent; 111 if (!chip->irq_set_affinity) 112 chip->irq_set_affinity = msi_domain_set_affinity; 113 if (!chip->irq_write_msi_msg) 114 chip->irq_write_msi_msg = platform_msi_write_msg; 115 } 116 117 static void platform_msi_free_descs(struct device *dev, int base, int nvec) 118 { 119 struct msi_desc *desc, *tmp; 120 121 list_for_each_entry_safe(desc, tmp, dev_to_msi_list(dev), list) { 122 if (desc->platform.msi_index >= base && 123 desc->platform.msi_index < (base + nvec)) { 124 list_del(&desc->list); 125 free_msi_entry(desc); 126 } 127 } 128 } 129 130 static int platform_msi_alloc_descs_with_irq(struct device *dev, int virq, 131 int nvec, 132 struct platform_msi_priv_data *data) 133 134 { 135 struct msi_desc *desc; 136 int i, base = 0; 137 138 if (!list_empty(dev_to_msi_list(dev))) { 139 desc = list_last_entry(dev_to_msi_list(dev), 140 struct msi_desc, list); 141 base = desc->platform.msi_index + 1; 142 } 143 144 for (i = 0; i < nvec; i++) { 145 desc = alloc_msi_entry(dev); 146 if (!desc) 147 break; 148 149 desc->platform.msi_priv_data = data; 150 desc->platform.msi_index = base + i; 151 desc->nvec_used = 1; 152 desc->irq = virq ? virq + i : 0; 153 154 list_add_tail(&desc->list, dev_to_msi_list(dev)); 155 } 156 157 if (i != nvec) { 158 /* Clean up the mess */ 159 platform_msi_free_descs(dev, base, nvec); 160 161 return -ENOMEM; 162 } 163 164 return 0; 165 } 166 167 static int platform_msi_alloc_descs(struct device *dev, int nvec, 168 struct platform_msi_priv_data *data) 169 170 { 171 return platform_msi_alloc_descs_with_irq(dev, 0, nvec, data); 172 } 173 174 /** 175 * platform_msi_create_irq_domain - Create a platform MSI interrupt domain 176 * @fwnode: Optional fwnode of the interrupt controller 177 * @info: MSI domain info 178 * @parent: Parent irq domain 179 * 180 * Updates the domain and chip ops and creates a platform MSI 181 * interrupt domain. 182 * 183 * Returns: 184 * A domain pointer or NULL in case of failure. 185 */ 186 struct irq_domain *platform_msi_create_irq_domain(struct fwnode_handle *fwnode, 187 struct msi_domain_info *info, 188 struct irq_domain *parent) 189 { 190 struct irq_domain *domain; 191 192 if (info->flags & MSI_FLAG_USE_DEF_DOM_OPS) 193 platform_msi_update_dom_ops(info); 194 if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS) 195 platform_msi_update_chip_ops(info); 196 197 domain = msi_create_irq_domain(fwnode, info, parent); 198 if (domain) 199 domain->bus_token = DOMAIN_BUS_PLATFORM_MSI; 200 201 return domain; 202 } 203 204 static struct platform_msi_priv_data * 205 platform_msi_alloc_priv_data(struct device *dev, unsigned int nvec, 206 irq_write_msi_msg_t write_msi_msg) 207 { 208 struct platform_msi_priv_data *datap; 209 /* 210 * Limit the number of interrupts to 256 per device. Should we 211 * need to bump this up, DEV_ID_SHIFT should be adjusted 212 * accordingly (which would impact the max number of MSI 213 * capable devices). 214 */ 215 if (!dev->msi_domain || !write_msi_msg || !nvec || nvec > MAX_DEV_MSIS) 216 return ERR_PTR(-EINVAL); 217 218 if (dev->msi_domain->bus_token != DOMAIN_BUS_PLATFORM_MSI) { 219 dev_err(dev, "Incompatible msi_domain, giving up\n"); 220 return ERR_PTR(-EINVAL); 221 } 222 223 /* Already had a helping of MSI? Greed... */ 224 if (!list_empty(dev_to_msi_list(dev))) 225 return ERR_PTR(-EBUSY); 226 227 datap = kzalloc(sizeof(*datap), GFP_KERNEL); 228 if (!datap) 229 return ERR_PTR(-ENOMEM); 230 231 datap->devid = ida_simple_get(&platform_msi_devid_ida, 232 0, 1 << DEV_ID_SHIFT, GFP_KERNEL); 233 if (datap->devid < 0) { 234 int err = datap->devid; 235 kfree(datap); 236 return ERR_PTR(err); 237 } 238 239 datap->write_msg = write_msi_msg; 240 datap->dev = dev; 241 242 return datap; 243 } 244 245 static void platform_msi_free_priv_data(struct platform_msi_priv_data *data) 246 { 247 ida_simple_remove(&platform_msi_devid_ida, data->devid); 248 kfree(data); 249 } 250 251 /** 252 * platform_msi_domain_alloc_irqs - Allocate MSI interrupts for @dev 253 * @dev: The device for which to allocate interrupts 254 * @nvec: The number of interrupts to allocate 255 * @write_msi_msg: Callback to write an interrupt message for @dev 256 * 257 * Returns: 258 * Zero for success, or an error code in case of failure 259 */ 260 int platform_msi_domain_alloc_irqs(struct device *dev, unsigned int nvec, 261 irq_write_msi_msg_t write_msi_msg) 262 { 263 struct platform_msi_priv_data *priv_data; 264 int err; 265 266 priv_data = platform_msi_alloc_priv_data(dev, nvec, write_msi_msg); 267 if (IS_ERR(priv_data)) 268 return PTR_ERR(priv_data); 269 270 err = platform_msi_alloc_descs(dev, nvec, priv_data); 271 if (err) 272 goto out_free_priv_data; 273 274 err = msi_domain_alloc_irqs(dev->msi_domain, dev, nvec); 275 if (err) 276 goto out_free_desc; 277 278 return 0; 279 280 out_free_desc: 281 platform_msi_free_descs(dev, 0, nvec); 282 out_free_priv_data: 283 platform_msi_free_priv_data(priv_data); 284 285 return err; 286 } 287 EXPORT_SYMBOL_GPL(platform_msi_domain_alloc_irqs); 288 289 /** 290 * platform_msi_domain_free_irqs - Free MSI interrupts for @dev 291 * @dev: The device for which to free interrupts 292 */ 293 void platform_msi_domain_free_irqs(struct device *dev) 294 { 295 if (!list_empty(dev_to_msi_list(dev))) { 296 struct msi_desc *desc; 297 298 desc = first_msi_entry(dev); 299 platform_msi_free_priv_data(desc->platform.msi_priv_data); 300 } 301 302 msi_domain_free_irqs(dev->msi_domain, dev); 303 platform_msi_free_descs(dev, 0, MAX_DEV_MSIS); 304 } 305 EXPORT_SYMBOL_GPL(platform_msi_domain_free_irqs); 306 307 /** 308 * platform_msi_get_host_data - Query the private data associated with 309 * a platform-msi domain 310 * @domain: The platform-msi domain 311 * 312 * Returns the private data provided when calling 313 * platform_msi_create_device_domain. 314 */ 315 void *platform_msi_get_host_data(struct irq_domain *domain) 316 { 317 struct platform_msi_priv_data *data = domain->host_data; 318 return data->host_data; 319 } 320 321 /** 322 * platform_msi_create_device_domain - Create a platform-msi domain 323 * 324 * @dev: The device generating the MSIs 325 * @nvec: The number of MSIs that need to be allocated 326 * @write_msi_msg: Callback to write an interrupt message for @dev 327 * @ops: The hierarchy domain operations to use 328 * @host_data: Private data associated to this domain 329 * 330 * Returns an irqdomain for @nvec interrupts 331 */ 332 struct irq_domain * 333 platform_msi_create_device_domain(struct device *dev, 334 unsigned int nvec, 335 irq_write_msi_msg_t write_msi_msg, 336 const struct irq_domain_ops *ops, 337 void *host_data) 338 { 339 struct platform_msi_priv_data *data; 340 struct irq_domain *domain; 341 int err; 342 343 data = platform_msi_alloc_priv_data(dev, nvec, write_msi_msg); 344 if (IS_ERR(data)) 345 return NULL; 346 347 data->host_data = host_data; 348 domain = irq_domain_create_hierarchy(dev->msi_domain, 0, nvec, 349 of_node_to_fwnode(dev->of_node), 350 ops, data); 351 if (!domain) 352 goto free_priv; 353 354 err = msi_domain_prepare_irqs(domain->parent, dev, nvec, &data->arg); 355 if (err) 356 goto free_domain; 357 358 return domain; 359 360 free_domain: 361 irq_domain_remove(domain); 362 free_priv: 363 platform_msi_free_priv_data(data); 364 return NULL; 365 } 366 367 /** 368 * platform_msi_domain_free - Free interrupts associated with a platform-msi 369 * domain 370 * 371 * @domain: The platform-msi domain 372 * @virq: The base irq from which to perform the free operation 373 * @nvec: How many interrupts to free from @virq 374 */ 375 void platform_msi_domain_free(struct irq_domain *domain, unsigned int virq, 376 unsigned int nvec) 377 { 378 struct platform_msi_priv_data *data = domain->host_data; 379 struct msi_desc *desc; 380 for_each_msi_entry(desc, data->dev) { 381 if (WARN_ON(!desc->irq || desc->nvec_used != 1)) 382 return; 383 if (!(desc->irq >= virq && desc->irq < (virq + nvec))) 384 continue; 385 386 irq_domain_free_irqs_common(domain, desc->irq, 1); 387 } 388 } 389 390 /** 391 * platform_msi_domain_alloc - Allocate interrupts associated with 392 * a platform-msi domain 393 * 394 * @domain: The platform-msi domain 395 * @virq: The base irq from which to perform the allocate operation 396 * @nvec: How many interrupts to free from @virq 397 * 398 * Return 0 on success, or an error code on failure. Must be called 399 * with irq_domain_mutex held (which can only be done as part of a 400 * top-level interrupt allocation). 401 */ 402 int platform_msi_domain_alloc(struct irq_domain *domain, unsigned int virq, 403 unsigned int nr_irqs) 404 { 405 struct platform_msi_priv_data *data = domain->host_data; 406 int err; 407 408 err = platform_msi_alloc_descs_with_irq(data->dev, virq, nr_irqs, data); 409 if (err) 410 return err; 411 412 err = msi_domain_populate_irqs(domain->parent, data->dev, 413 virq, nr_irqs, &data->arg); 414 if (err) 415 platform_msi_domain_free(domain, virq, nr_irqs); 416 417 return err; 418 } 419