drivers/base/platform-msi.c

   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, 1, NULL);
 146                 if (!desc)
 147                         break;
 148
 149                 desc->platform.msi_priv_data = data;
 150                 desc->platform.msi_index = base + i;
 151                 desc->irq = virq ? virq + i : 0;
 152
 153                 list_add_tail(&desc->list, dev_to_msi_list(dev));
 154         }
 155
 156         if (i != nvec) {
 157                 /* Clean up the mess */
 158                 platform_msi_free_descs(dev, base, nvec);
 159
 160                 return -ENOMEM;
 161         }
 162
 163         return 0;
 164 }
 165
 166 static int platform_msi_alloc_descs(struct device *dev, int nvec,
 167                                     struct platform_msi_priv_data *data)
 168
 169 {
 170         return platform_msi_alloc_descs_with_irq(dev, 0, nvec, data);
 171 }
 172
 173 /**
 174  * platform_msi_create_irq_domain - Create a platform MSI interrupt domain
 175  * @fwnode:             Optional fwnode of the interrupt controller
 176  * @info:       MSI domain info
 177  * @parent:     Parent irq domain
 178  *
 179  * Updates the domain and chip ops and creates a platform MSI
 180  * interrupt domain.
 181  *
 182  * Returns:
 183  * A domain pointer or NULL in case of failure.
 184  */
 185 struct irq_domain *platform_msi_create_irq_domain(struct fwnode_handle *fwnode,
 186                                                   struct msi_domain_info *info,
 187                                                   struct irq_domain *parent)
 188 {
 189         struct irq_domain *domain;
 190
 191         if (info->flags & MSI_FLAG_USE_DEF_DOM_OPS)
 192                 platform_msi_update_dom_ops(info);
 193         if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)
 194                 platform_msi_update_chip_ops(info);
 195
 196         domain = msi_create_irq_domain(fwnode, info, parent);
 197         if (domain)
 198                 domain->bus_token = DOMAIN_BUS_PLATFORM_MSI;
 199
 200         return domain;
 201 }
 202
 203 static struct platform_msi_priv_data *
 204 platform_msi_alloc_priv_data(struct device *dev, unsigned int nvec,
 205                              irq_write_msi_msg_t write_msi_msg)
 206 {
 207         struct platform_msi_priv_data *datap;
 208         /*
 209          * Limit the number of interrupts to 2048 per device. Should we
 210          * need to bump this up, DEV_ID_SHIFT should be adjusted
 211          * accordingly (which would impact the max number of MSI
 212          * capable devices).
 213          */
 214         if (!dev->msi_domain || !write_msi_msg || !nvec || nvec > MAX_DEV_MSIS)
 215                 return ERR_PTR(-EINVAL);
 216
 217         if (dev->msi_domain->bus_token != DOMAIN_BUS_PLATFORM_MSI) {
 218                 dev_err(dev, "Incompatible msi_domain, giving up\n");
 219                 return ERR_PTR(-EINVAL);
 220         }
 221
 222         /* Already had a helping of MSI? Greed... */
 223         if (!list_empty(dev_to_msi_list(dev)))
 224                 return ERR_PTR(-EBUSY);
 225
 226         datap = kzalloc(sizeof(*datap), GFP_KERNEL);
 227         if (!datap)
 228                 return ERR_PTR(-ENOMEM);
 229
 230         datap->devid = ida_simple_get(&platform_msi_devid_ida,
 231                                       0, 1 << DEV_ID_SHIFT, GFP_KERNEL);
 232         if (datap->devid < 0) {
 233                 int err = datap->devid;
 234                 kfree(datap);
 235                 return ERR_PTR(err);
 236         }
 237
 238         datap->write_msg = write_msi_msg;
 239         datap->dev = dev;
 240
 241         return datap;
 242 }
 243
 244 static void platform_msi_free_priv_data(struct platform_msi_priv_data *data)
 245 {
 246         ida_simple_remove(&platform_msi_devid_ida, data->devid);
 247         kfree(data);
 248 }
 249
 250 /**
 251  * platform_msi_domain_alloc_irqs - Allocate MSI interrupts for @dev
 252  * @dev:                The device for which to allocate interrupts
 253  * @nvec:               The number of interrupts to allocate
 254  * @write_msi_msg:      Callback to write an interrupt message for @dev
 255  *
 256  * Returns:
 257  * Zero for success, or an error code in case of failure
 258  */
 259 int platform_msi_domain_alloc_irqs(struct device *dev, unsigned int nvec,
 260                                    irq_write_msi_msg_t write_msi_msg)
 261 {
 262         struct platform_msi_priv_data *priv_data;
 263         int err;
 264
 265         priv_data = platform_msi_alloc_priv_data(dev, nvec, write_msi_msg);
 266         if (IS_ERR(priv_data))
 267                 return PTR_ERR(priv_data);
 268
 269         err = platform_msi_alloc_descs(dev, nvec, priv_data);
 270         if (err)
 271                 goto out_free_priv_data;
 272
 273         err = msi_domain_alloc_irqs(dev->msi_domain, dev, nvec);
 274         if (err)
 275                 goto out_free_desc;
 276
 277         return 0;
 278
 279 out_free_desc:
 280         platform_msi_free_descs(dev, 0, nvec);
 281 out_free_priv_data:
 282         platform_msi_free_priv_data(priv_data);
 283
 284         return err;
 285 }
 286 EXPORT_SYMBOL_GPL(platform_msi_domain_alloc_irqs);
 287
 288 /**
 289  * platform_msi_domain_free_irqs - Free MSI interrupts for @dev
 290  * @dev:        The device for which to free interrupts
 291  */
 292 void platform_msi_domain_free_irqs(struct device *dev)
 293 {
 294         if (!list_empty(dev_to_msi_list(dev))) {
 295                 struct msi_desc *desc;
 296
 297                 desc = first_msi_entry(dev);
 298                 platform_msi_free_priv_data(desc->platform.msi_priv_data);
 299         }
 300
 301         msi_domain_free_irqs(dev->msi_domain, dev);
 302         platform_msi_free_descs(dev, 0, MAX_DEV_MSIS);
 303 }
 304 EXPORT_SYMBOL_GPL(platform_msi_domain_free_irqs);
 305
 306 /**
 307  * platform_msi_get_host_data - Query the private data associated with
 308  *                              a platform-msi domain
 309  * @domain:     The platform-msi domain
 310  *
 311  * Returns the private data provided when calling
 312  * platform_msi_create_device_domain.
 313  */
 314 void *platform_msi_get_host_data(struct irq_domain *domain)
 315 {
 316         struct platform_msi_priv_data *data = domain->host_data;
 317         return data->host_data;
 318 }
 319
 320 /**
 321  * platform_msi_create_device_domain - Create a platform-msi domain
 322  *
 323  * @dev:                The device generating the MSIs
 324  * @nvec:               The number of MSIs that need to be allocated
 325  * @write_msi_msg:      Callback to write an interrupt message for @dev
 326  * @ops:                The hierarchy domain operations to use
 327  * @host_data:          Private data associated to this domain
 328  *
 329  * Returns an irqdomain for @nvec interrupts
 330  */
 331 struct irq_domain *
 332 platform_msi_create_device_domain(struct device *dev,
 333                                   unsigned int nvec,
 334                                   irq_write_msi_msg_t write_msi_msg,
 335                                   const struct irq_domain_ops *ops,
 336                                   void *host_data)
 337 {
 338         struct platform_msi_priv_data *data;
 339         struct irq_domain *domain;
 340         int err;
 341
 342         data = platform_msi_alloc_priv_data(dev, nvec, write_msi_msg);
 343         if (IS_ERR(data))
 344                 return NULL;
 345
 346         data->host_data = host_data;
 347         domain = irq_domain_create_hierarchy(dev->msi_domain, 0, nvec,
 348                                              dev->fwnode, ops, data);
 349         if (!domain)
 350                 goto free_priv;
 351
 352         err = msi_domain_prepare_irqs(domain->parent, dev, nvec, &data->arg);
 353         if (err)
 354                 goto free_domain;
 355
 356         return domain;
 357
 358 free_domain:
 359         irq_domain_remove(domain);
 360 free_priv:
 361         platform_msi_free_priv_data(data);
 362         return NULL;
 363 }
 364
 365 /**
 366  * platform_msi_domain_free - Free interrupts associated with a platform-msi
 367  *                            domain
 368  *
 369  * @domain:     The platform-msi domain
 370  * @virq:       The base irq from which to perform the free operation
 371  * @nvec:       How many interrupts to free from @virq
 372  */
 373 void platform_msi_domain_free(struct irq_domain *domain, unsigned int virq,
 374                               unsigned int nvec)
 375 {
 376         struct platform_msi_priv_data *data = domain->host_data;
 377         struct msi_desc *desc;
 378         for_each_msi_entry(desc, data->dev) {
 379                 if (WARN_ON(!desc->irq || desc->nvec_used != 1))
 380                         return;
 381                 if (!(desc->irq >= virq && desc->irq < (virq + nvec)))
 382                         continue;
 383
 384                 irq_domain_free_irqs_common(domain, desc->irq, 1);
 385         }
 386 }
 387
 388 /**
 389  * platform_msi_domain_alloc - Allocate interrupts associated with
 390  *                             a platform-msi domain
 391  *
 392  * @domain:     The platform-msi domain
 393  * @virq:       The base irq from which to perform the allocate operation
 394  * @nvec:       How many interrupts to free from @virq
 395  *
 396  * Return 0 on success, or an error code on failure. Must be called
 397  * with irq_domain_mutex held (which can only be done as part of a
 398  * top-level interrupt allocation).
 399  */
 400 int platform_msi_domain_alloc(struct irq_domain *domain, unsigned int virq,
 401                               unsigned int nr_irqs)
 402 {
 403         struct platform_msi_priv_data *data = domain->host_data;
 404         int err;
 405
 406         err = platform_msi_alloc_descs_with_irq(data->dev, virq, nr_irqs, data);
 407         if (err)
 408                 return err;
 409
 410         err = msi_domain_populate_irqs(domain->parent, data->dev,
 411                                        virq, nr_irqs, &data->arg);
 412         if (err)
 413                 platform_msi_domain_free(domain, virq, nr_irqs);
 414
 415         return err;
 416 }