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
  63 static void platform_msi_set_proxy_dev(msi_alloc_info_t *arg)
  64 {
  65         arg->flags |= MSI_ALLOC_FLAGS_PROXY_DEVICE;
  66 }
  67 #else
  68 #define platform_msi_set_desc           NULL
  69 #define platform_msi_init               NULL
  70 #define platform_msi_set_proxy_dev(x)   do {} while(0)
  71 #endif
  72
  73 static void platform_msi_update_dom_ops(struct msi_domain_info *info)
  74 {
  75         struct msi_domain_ops *ops = info->ops;
  76
  77         BUG_ON(!ops);
  78
  79         if (ops->msi_init == NULL)
  80                 ops->msi_init = platform_msi_init;
  81         if (ops->set_desc == NULL)
  82                 ops->set_desc = platform_msi_set_desc;
  83 }
  84
  85 static void platform_msi_write_msg(struct irq_data *data, struct msi_msg *msg)
  86 {
  87         struct msi_desc *desc = irq_data_get_msi_desc(data);
  88         struct platform_msi_priv_data *priv_data;
  89
  90         priv_data = desc->platform.msi_priv_data;
  91
  92         priv_data->write_msg(desc, msg);
  93 }
  94
  95 static void platform_msi_update_chip_ops(struct msi_domain_info *info)
  96 {
  97         struct irq_chip *chip = info->chip;
  98
  99         BUG_ON(!chip);
 100         if (!chip->irq_mask)
 101                 chip->irq_mask = irq_chip_mask_parent;
 102         if (!chip->irq_unmask)
 103                 chip->irq_unmask = irq_chip_unmask_parent;
 104         if (!chip->irq_eoi)
 105                 chip->irq_eoi = irq_chip_eoi_parent;
 106         if (!chip->irq_set_affinity)
 107                 chip->irq_set_affinity = msi_domain_set_affinity;
 108         if (!chip->irq_write_msi_msg)
 109                 chip->irq_write_msi_msg = platform_msi_write_msg;
 110         if (WARN_ON((info->flags & MSI_FLAG_LEVEL_CAPABLE) &&
 111                     !(chip->flags & IRQCHIP_SUPPORTS_LEVEL_MSI)))
 112                 info->flags &= ~MSI_FLAG_LEVEL_CAPABLE;
 113 }
 114
 115 static void platform_msi_free_descs(struct device *dev, int base, int nvec)
 116 {
 117         struct msi_desc *desc, *tmp;
 118
 119         list_for_each_entry_safe(desc, tmp, dev_to_msi_list(dev), list) {
 120                 if (desc->platform.msi_index >= base &&
 121                     desc->platform.msi_index < (base + nvec)) {
 122                         list_del(&desc->list);
 123                         free_msi_entry(desc);
 124                 }
 125         }
 126 }
 127
 128 static int platform_msi_alloc_descs_with_irq(struct device *dev, int virq,
 129                                              int nvec,
 130                                              struct platform_msi_priv_data *data)
 131
 132 {
 133         struct msi_desc *desc;
 134         int i, base = 0;
 135
 136         if (!list_empty(dev_to_msi_list(dev))) {
 137                 desc = list_last_entry(dev_to_msi_list(dev),
 138                                        struct msi_desc, list);
 139                 base = desc->platform.msi_index + 1;
 140         }
 141
 142         for (i = 0; i < nvec; i++) {
 143                 desc = alloc_msi_entry(dev, 1, NULL);
 144                 if (!desc)
 145                         break;
 146
 147                 desc->platform.msi_priv_data = data;
 148                 desc->platform.msi_index = base + i;
 149                 desc->irq = virq ? virq + i : 0;
 150
 151                 list_add_tail(&desc->list, dev_to_msi_list(dev));
 152         }
 153
 154         if (i != nvec) {
 155                 /* Clean up the mess */
 156                 platform_msi_free_descs(dev, base, nvec);
 157
 158                 return -ENOMEM;
 159         }
 160
 161         return 0;
 162 }
 163
 164 static int platform_msi_alloc_descs(struct device *dev, int nvec,
 165                                     struct platform_msi_priv_data *data)
 166
 167 {
 168         return platform_msi_alloc_descs_with_irq(dev, 0, nvec, data);
 169 }
 170
 171 /**
 172  * platform_msi_create_irq_domain - Create a platform MSI interrupt domain
 173  * @fwnode:             Optional fwnode of the interrupt controller
 174  * @info:       MSI domain info
 175  * @parent:     Parent irq domain
 176  *
 177  * Updates the domain and chip ops and creates a platform MSI
 178  * interrupt domain.
 179  *
 180  * Returns:
 181  * A domain pointer or NULL in case of failure.
 182  */
 183 struct irq_domain *platform_msi_create_irq_domain(struct fwnode_handle *fwnode,
 184                                                   struct msi_domain_info *info,
 185                                                   struct irq_domain *parent)
 186 {
 187         struct irq_domain *domain;
 188
 189         if (info->flags & MSI_FLAG_USE_DEF_DOM_OPS)
 190                 platform_msi_update_dom_ops(info);
 191         if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)
 192                 platform_msi_update_chip_ops(info);
 193
 194         domain = msi_create_irq_domain(fwnode, info, parent);
 195         if (domain)
 196                 irq_domain_update_bus_token(domain, DOMAIN_BUS_PLATFORM_MSI);
 197
 198         return domain;
 199 }
 200
 201 static struct platform_msi_priv_data *
 202 platform_msi_alloc_priv_data(struct device *dev, unsigned int nvec,
 203                              irq_write_msi_msg_t write_msi_msg)
 204 {
 205         struct platform_msi_priv_data *datap;
 206         /*
 207          * Limit the number of interrupts to 2048 per device. Should we
 208          * need to bump this up, DEV_ID_SHIFT should be adjusted
 209          * accordingly (which would impact the max number of MSI
 210          * capable devices).
 211          */
 212         if (!dev->msi_domain || !write_msi_msg || !nvec || nvec > MAX_DEV_MSIS)
 213                 return ERR_PTR(-EINVAL);
 214
 215         if (dev->msi_domain->bus_token != DOMAIN_BUS_PLATFORM_MSI) {
 216                 dev_err(dev, "Incompatible msi_domain, giving up\n");
 217                 return ERR_PTR(-EINVAL);
 218         }
 219
 220         /* Already had a helping of MSI? Greed... */
 221         if (!list_empty(dev_to_msi_list(dev)))
 222                 return ERR_PTR(-EBUSY);
 223
 224         datap = kzalloc(sizeof(*datap), GFP_KERNEL);
 225         if (!datap)
 226                 return ERR_PTR(-ENOMEM);
 227
 228         datap->devid = ida_simple_get(&platform_msi_devid_ida,
 229                                       0, 1 << DEV_ID_SHIFT, GFP_KERNEL);
 230         if (datap->devid < 0) {
 231                 int err = datap->devid;
 232                 kfree(datap);
 233                 return ERR_PTR(err);
 234         }
 235
 236         datap->write_msg = write_msi_msg;
 237         datap->dev = dev;
 238
 239         return datap;
 240 }
 241
 242 static void platform_msi_free_priv_data(struct platform_msi_priv_data *data)
 243 {
 244         ida_simple_remove(&platform_msi_devid_ida, data->devid);
 245         kfree(data);
 246 }
 247
 248 /**
 249  * platform_msi_domain_alloc_irqs - Allocate MSI interrupts for @dev
 250  * @dev:                The device for which to allocate interrupts
 251  * @nvec:               The number of interrupts to allocate
 252  * @write_msi_msg:      Callback to write an interrupt message for @dev
 253  *
 254  * Returns:
 255  * Zero for success, or an error code in case of failure
 256  */
 257 int platform_msi_domain_alloc_irqs(struct device *dev, unsigned int nvec,
 258                                    irq_write_msi_msg_t write_msi_msg)
 259 {
 260         struct platform_msi_priv_data *priv_data;
 261         int err;
 262
 263         priv_data = platform_msi_alloc_priv_data(dev, nvec, write_msi_msg);
 264         if (IS_ERR(priv_data))
 265                 return PTR_ERR(priv_data);
 266
 267         err = platform_msi_alloc_descs(dev, nvec, priv_data);
 268         if (err)
 269                 goto out_free_priv_data;
 270
 271         err = msi_domain_alloc_irqs(dev->msi_domain, dev, nvec);
 272         if (err)
 273                 goto out_free_desc;
 274
 275         return 0;
 276
 277 out_free_desc:
 278         platform_msi_free_descs(dev, 0, nvec);
 279 out_free_priv_data:
 280         platform_msi_free_priv_data(priv_data);
 281
 282         return err;
 283 }
 284 EXPORT_SYMBOL_GPL(platform_msi_domain_alloc_irqs);
 285
 286 /**
 287  * platform_msi_domain_free_irqs - Free MSI interrupts for @dev
 288  * @dev:        The device for which to free interrupts
 289  */
 290 void platform_msi_domain_free_irqs(struct device *dev)
 291 {
 292         if (!list_empty(dev_to_msi_list(dev))) {
 293                 struct msi_desc *desc;
 294
 295                 desc = first_msi_entry(dev);
 296                 platform_msi_free_priv_data(desc->platform.msi_priv_data);
 297         }
 298
 299         msi_domain_free_irqs(dev->msi_domain, dev);
 300         platform_msi_free_descs(dev, 0, MAX_DEV_MSIS);
 301 }
 302 EXPORT_SYMBOL_GPL(platform_msi_domain_free_irqs);
 303
 304 /**
 305  * platform_msi_get_host_data - Query the private data associated with
 306  *                              a platform-msi domain
 307  * @domain:     The platform-msi domain
 308  *
 309  * Returns the private data provided when calling
 310  * platform_msi_create_device_domain.
 311  */
 312 void *platform_msi_get_host_data(struct irq_domain *domain)
 313 {
 314         struct platform_msi_priv_data *data = domain->host_data;
 315         return data->host_data;
 316 }
 317
 318 /**
 319  * platform_msi_create_device_domain - Create a platform-msi domain
 320  *
 321  * @dev:                The device generating the MSIs
 322  * @nvec:               The number of MSIs that need to be allocated
 323  * @write_msi_msg:      Callback to write an interrupt message for @dev
 324  * @ops:                The hierarchy domain operations to use
 325  * @host_data:          Private data associated to this domain
 326  *
 327  * Returns an irqdomain for @nvec interrupts
 328  */
 329 struct irq_domain *
 330 __platform_msi_create_device_domain(struct device *dev,
 331                                     unsigned int nvec,
 332                                     bool is_tree,
 333                                     irq_write_msi_msg_t write_msi_msg,
 334                                     const struct irq_domain_ops *ops,
 335                                     void *host_data)
 336 {
 337         struct platform_msi_priv_data *data;
 338         struct irq_domain *domain;
 339         int err;
 340
 341         data = platform_msi_alloc_priv_data(dev, nvec, write_msi_msg);
 342         if (IS_ERR(data))
 343                 return NULL;
 344
 345         data->host_data = host_data;
 346         domain = irq_domain_create_hierarchy(dev->msi_domain, 0,
 347                                              is_tree ? 0 : nvec,
 348                                              dev->fwnode, ops, data);
 349         if (!domain)
 350                 goto free_priv;
 351
 352         platform_msi_set_proxy_dev(&data->arg);
 353         err = msi_domain_prepare_irqs(domain->parent, dev, nvec, &data->arg);
 354         if (err)
 355                 goto free_domain;
 356
 357         return domain;
 358
 359 free_domain:
 360         irq_domain_remove(domain);
 361 free_priv:
 362         platform_msi_free_priv_data(data);
 363         return NULL;
 364 }
 365
 366 /**
 367  * platform_msi_domain_free - Free interrupts associated with a platform-msi
 368  *                            domain
 369  *
 370  * @domain:     The platform-msi domain
 371  * @virq:       The base irq from which to perform the free operation
 372  * @nvec:       How many interrupts to free from @virq
 373  */
 374 void platform_msi_domain_free(struct irq_domain *domain, unsigned int virq,
 375                               unsigned int nvec)
 376 {
 377         struct platform_msi_priv_data *data = domain->host_data;
 378         struct msi_desc *desc, *tmp;
 379         for_each_msi_entry_safe(desc, tmp, data->dev) {
 380                 if (WARN_ON(!desc->irq || desc->nvec_used != 1))
 381                         return;
 382                 if (!(desc->irq >= virq && desc->irq < (virq + nvec)))
 383                         continue;
 384
 385                 irq_domain_free_irqs_common(domain, desc->irq, 1);
 386                 list_del(&desc->list);
 387                 free_msi_entry(desc);
 388         }
 389 }
 390
 391 /**
 392  * platform_msi_domain_alloc - Allocate interrupts associated with
 393  *                             a platform-msi domain
 394  *
 395  * @domain:     The platform-msi domain
 396  * @virq:       The base irq from which to perform the allocate operation
 397  * @nr_irqs:    How many interrupts to free from @virq
 398  *
 399  * Return 0 on success, or an error code on failure. Must be called
 400  * with irq_domain_mutex held (which can only be done as part of a
 401  * top-level interrupt allocation).
 402  */
 403 int platform_msi_domain_alloc(struct irq_domain *domain, unsigned int virq,
 404                               unsigned int nr_irqs)
 405 {
 406         struct platform_msi_priv_data *data = domain->host_data;
 407         int err;
 408
 409         err = platform_msi_alloc_descs_with_irq(data->dev, virq, nr_irqs, data);
 410         if (err)
 411                 return err;
 412
 413         err = msi_domain_populate_irqs(domain->parent, data->dev,
 414                                        virq, nr_irqs, &data->arg);
 415         if (err)
 416                 platform_msi_domain_free(domain, virq, nr_irqs);
 417
 418         return err;
 419 }