drivers/base/platform-msi.c

   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 }