arch/powerpc/platforms/cell/axon_msi.c

   1 /*
   2  * Copyright 2007, Michael Ellerman, IBM Corporation.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version
   7  * 2 of the License, or (at your option) any later version.
   8  */
   9
  10
  11 #include <linux/interrupt.h>
  12 #include <linux/irq.h>
  13 #include <linux/kernel.h>
  14 #include <linux/pci.h>
  15 #include <linux/msi.h>
  16 #include <linux/export.h>
  17 #include <linux/of_platform.h>
  18 #include <linux/debugfs.h>
  19 #include <linux/slab.h>
  20
  21 #include <asm/dcr.h>
  22 #include <asm/machdep.h>
  23 #include <asm/prom.h>
  24
  25
  26 /*
  27  * MSIC registers, specified as offsets from dcr_base
  28  */
  29 #define MSIC_CTRL_REG   0x0
  30
  31 /* Base Address registers specify FIFO location in BE memory */
  32 #define MSIC_BASE_ADDR_HI_REG   0x3
  33 #define MSIC_BASE_ADDR_LO_REG   0x4
  34
  35 /* Hold the read/write offsets into the FIFO */
  36 #define MSIC_READ_OFFSET_REG    0x5
  37 #define MSIC_WRITE_OFFSET_REG   0x6
  38
  39
  40 /* MSIC control register flags */
  41 #define MSIC_CTRL_ENABLE                0x0001
  42 #define MSIC_CTRL_FIFO_FULL_ENABLE      0x0002
  43 #define MSIC_CTRL_IRQ_ENABLE            0x0008
  44 #define MSIC_CTRL_FULL_STOP_ENABLE      0x0010
  45
  46 /*
  47  * The MSIC can be configured to use a FIFO of 32KB, 64KB, 128KB or 256KB.
  48  * Currently we're using a 64KB FIFO size.
  49  */
  50 #define MSIC_FIFO_SIZE_SHIFT    16
  51 #define MSIC_FIFO_SIZE_BYTES    (1 << MSIC_FIFO_SIZE_SHIFT)
  52
  53 /*
  54  * To configure the FIFO size as (1 << n) bytes, we write (n - 15) into bits
  55  * 8-9 of the MSIC control reg.
  56  */
  57 #define MSIC_CTRL_FIFO_SIZE     (((MSIC_FIFO_SIZE_SHIFT - 15) << 8) & 0x300)
  58
  59 /*
  60  * We need to mask the read/write offsets to make sure they stay within
  61  * the bounds of the FIFO. Also they should always be 16-byte aligned.
  62  */
  63 #define MSIC_FIFO_SIZE_MASK     ((MSIC_FIFO_SIZE_BYTES - 1) & ~0xFu)
  64
  65 /* Each entry in the FIFO is 16 bytes, the first 4 bytes hold the irq # */
  66 #define MSIC_FIFO_ENTRY_SIZE    0x10
  67
  68
  69 struct axon_msic {
  70         struct irq_domain *irq_domain;
  71         __le32 *fifo_virt;
  72         dma_addr_t fifo_phys;
  73         dcr_host_t dcr_host;
  74         u32 read_offset;
  75 #ifdef DEBUG
  76         u32 __iomem *trigger;
  77 #endif
  78 };
  79
  80 #ifdef DEBUG
  81 void axon_msi_debug_setup(struct device_node *dn, struct axon_msic *msic);
  82 #else
  83 static inline void axon_msi_debug_setup(struct device_node *dn,
  84                                         struct axon_msic *msic) { }
  85 #endif
  86
  87
  88 static void msic_dcr_write(struct axon_msic *msic, unsigned int dcr_n, u32 val)
  89 {
  90         pr_devel("axon_msi: dcr_write(0x%x, 0x%x)\n", val, dcr_n);
  91
  92         dcr_write(msic->dcr_host, dcr_n, val);
  93 }
  94
  95 static void axon_msi_cascade(unsigned int irq, struct irq_desc *desc)
  96 {
  97         struct irq_chip *chip = irq_desc_get_chip(desc);
  98         struct axon_msic *msic = irq_get_handler_data(irq);
  99         u32 write_offset, msi;
 100         int idx;
 101         int retry = 0;
 102
 103         write_offset = dcr_read(msic->dcr_host, MSIC_WRITE_OFFSET_REG);
 104         pr_devel("axon_msi: original write_offset 0x%x\n", write_offset);
 105
 106         /* write_offset doesn't wrap properly, so we have to mask it */
 107         write_offset &= MSIC_FIFO_SIZE_MASK;
 108
 109         while (msic->read_offset != write_offset && retry < 100) {
 110                 idx  = msic->read_offset / sizeof(__le32);
 111                 msi  = le32_to_cpu(msic->fifo_virt[idx]);
 112                 msi &= 0xFFFF;
 113
 114                 pr_devel("axon_msi: woff %x roff %x msi %x\n",
 115                           write_offset, msic->read_offset, msi);
 116
 117                 if (msi < nr_irqs && irq_get_chip_data(msi) == msic) {
 118                         generic_handle_irq(msi);
 119                         msic->fifo_virt[idx] = cpu_to_le32(0xffffffff);
 120                 } else {
 121                         /*
 122                          * Reading the MSIC_WRITE_OFFSET_REG does not
 123                          * reliably flush the outstanding DMA to the
 124                          * FIFO buffer. Here we were reading stale
 125                          * data, so we need to retry.
 126                          */
 127                         udelay(1);
 128                         retry++;
 129                         pr_devel("axon_msi: invalid irq 0x%x!\n", msi);
 130                         continue;
 131                 }
 132
 133                 if (retry) {
 134                         pr_devel("axon_msi: late irq 0x%x, retry %d\n",
 135                                  msi, retry);
 136                         retry = 0;
 137                 }
 138
 139                 msic->read_offset += MSIC_FIFO_ENTRY_SIZE;
 140                 msic->read_offset &= MSIC_FIFO_SIZE_MASK;
 141         }
 142
 143         if (retry) {
 144                 printk(KERN_WARNING "axon_msi: irq timed out\n");
 145
 146                 msic->read_offset += MSIC_FIFO_ENTRY_SIZE;
 147                 msic->read_offset &= MSIC_FIFO_SIZE_MASK;
 148         }
 149
 150         chip->irq_eoi(&desc->irq_data);
 151 }
 152
 153 static struct axon_msic *find_msi_translator(struct pci_dev *dev)
 154 {
 155         struct irq_domain *irq_domain;
 156         struct device_node *dn, *tmp;
 157         const phandle *ph;
 158         struct axon_msic *msic = NULL;
 159
 160         dn = of_node_get(pci_device_to_OF_node(dev));
 161         if (!dn) {
 162                 dev_dbg(&dev->dev, "axon_msi: no pci_dn found\n");
 163                 return NULL;
 164         }
 165
 166         for (; dn; dn = of_get_next_parent(dn)) {
 167                 ph = of_get_property(dn, "msi-translator", NULL);
 168                 if (ph)
 169                         break;
 170         }
 171
 172         if (!ph) {
 173                 dev_dbg(&dev->dev,
 174                         "axon_msi: no msi-translator property found\n");
 175                 goto out_error;
 176         }
 177
 178         tmp = dn;
 179         dn = of_find_node_by_phandle(*ph);
 180         of_node_put(tmp);
 181         if (!dn) {
 182                 dev_dbg(&dev->dev,
 183                         "axon_msi: msi-translator doesn't point to a node\n");
 184                 goto out_error;
 185         }
 186
 187         irq_domain = irq_find_host(dn);
 188         if (!irq_domain) {
 189                 dev_dbg(&dev->dev, "axon_msi: no irq_domain found for node %s\n",
 190                         dn->full_name);
 191                 goto out_error;
 192         }
 193
 194         msic = irq_domain->host_data;
 195
 196 out_error:
 197         of_node_put(dn);
 198
 199         return msic;
 200 }
 201
 202 static int setup_msi_msg_address(struct pci_dev *dev, struct msi_msg *msg)
 203 {
 204         struct device_node *dn;
 205         struct msi_desc *entry;
 206         int len;
 207         const u32 *prop;
 208
 209         dn = of_node_get(pci_device_to_OF_node(dev));
 210         if (!dn) {
 211                 dev_dbg(&dev->dev, "axon_msi: no pci_dn found\n");
 212                 return -ENODEV;
 213         }
 214
 215         entry = list_first_entry(&dev->msi_list, struct msi_desc, list);
 216
 217         for (; dn; dn = of_get_next_parent(dn)) {
 218                 if (entry->msi_attrib.is_64) {
 219                         prop = of_get_property(dn, "msi-address-64", &len);
 220                         if (prop)
 221                                 break;
 222                 }
 223
 224                 prop = of_get_property(dn, "msi-address-32", &len);
 225                 if (prop)
 226                         break;
 227         }
 228
 229         if (!prop) {
 230                 dev_dbg(&dev->dev,
 231                         "axon_msi: no msi-address-(32|64) properties found\n");
 232                 return -ENOENT;
 233         }
 234
 235         switch (len) {
 236         case 8:
 237                 msg->address_hi = prop[0];
 238                 msg->address_lo = prop[1];
 239                 break;
 240         case 4:
 241                 msg->address_hi = 0;
 242                 msg->address_lo = prop[0];
 243                 break;
 244         default:
 245                 dev_dbg(&dev->dev,
 246                         "axon_msi: malformed msi-address-(32|64) property\n");
 247                 of_node_put(dn);
 248                 return -EINVAL;
 249         }
 250
 251         of_node_put(dn);
 252
 253         return 0;
 254 }
 255
 256 static int axon_msi_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
 257 {
 258         unsigned int virq, rc;
 259         struct msi_desc *entry;
 260         struct msi_msg msg;
 261         struct axon_msic *msic;
 262
 263         msic = find_msi_translator(dev);
 264         if (!msic)
 265                 return -ENODEV;
 266
 267         rc = setup_msi_msg_address(dev, &msg);
 268         if (rc)
 269                 return rc;
 270
 271         list_for_each_entry(entry, &dev->msi_list, list) {
 272                 virq = irq_create_direct_mapping(msic->irq_domain);
 273                 if (virq == NO_IRQ) {
 274                         dev_warn(&dev->dev,
 275                                  "axon_msi: virq allocation failed!\n");
 276                         return -1;
 277                 }
 278                 dev_dbg(&dev->dev, "axon_msi: allocated virq 0x%x\n", virq);
 279
 280                 irq_set_msi_desc(virq, entry);
 281                 msg.data = virq;
 282                 pci_write_msi_msg(virq, &msg);
 283         }
 284
 285         return 0;
 286 }
 287
 288 static void axon_msi_teardown_msi_irqs(struct pci_dev *dev)
 289 {
 290         struct msi_desc *entry;
 291
 292         dev_dbg(&dev->dev, "axon_msi: tearing down msi irqs\n");
 293
 294         list_for_each_entry(entry, &dev->msi_list, list) {
 295                 if (entry->irq == NO_IRQ)
 296                         continue;
 297
 298                 irq_set_msi_desc(entry->irq, NULL);
 299                 irq_dispose_mapping(entry->irq);
 300         }
 301 }
 302
 303 static struct irq_chip msic_irq_chip = {
 304         .irq_mask       = pci_msi_mask_irq,
 305         .irq_unmask     = pci_msi_unmask_irq,
 306         .irq_shutdown   = pci_msi_mask_irq,
 307         .name           = "AXON-MSI",
 308 };
 309
 310 static int msic_host_map(struct irq_domain *h, unsigned int virq,
 311                          irq_hw_number_t hw)
 312 {
 313         irq_set_chip_data(virq, h->host_data);
 314         irq_set_chip_and_handler(virq, &msic_irq_chip, handle_simple_irq);
 315
 316         return 0;
 317 }
 318
 319 static const struct irq_domain_ops msic_host_ops = {
 320         .map    = msic_host_map,
 321 };
 322
 323 static void axon_msi_shutdown(struct platform_device *device)
 324 {
 325         struct axon_msic *msic = dev_get_drvdata(&device->dev);
 326         u32 tmp;
 327
 328         pr_devel("axon_msi: disabling %s\n",
 329                   msic->irq_domain->of_node->full_name);
 330         tmp  = dcr_read(msic->dcr_host, MSIC_CTRL_REG);
 331         tmp &= ~MSIC_CTRL_ENABLE & ~MSIC_CTRL_IRQ_ENABLE;
 332         msic_dcr_write(msic, MSIC_CTRL_REG, tmp);
 333 }
 334
 335 static int axon_msi_probe(struct platform_device *device)
 336 {
 337         struct device_node *dn = device->dev.of_node;
 338         struct axon_msic *msic;
 339         unsigned int virq;
 340         int dcr_base, dcr_len;
 341
 342         pr_devel("axon_msi: setting up dn %s\n", dn->full_name);
 343
 344         msic = kzalloc(sizeof(struct axon_msic), GFP_KERNEL);
 345         if (!msic) {
 346                 printk(KERN_ERR "axon_msi: couldn't allocate msic for %s\n",
 347                        dn->full_name);
 348                 goto out;
 349         }
 350
 351         dcr_base = dcr_resource_start(dn, 0);
 352         dcr_len = dcr_resource_len(dn, 0);
 353
 354         if (dcr_base == 0 || dcr_len == 0) {
 355                 printk(KERN_ERR
 356                        "axon_msi: couldn't parse dcr properties on %s\n",
 357                         dn->full_name);
 358                 goto out_free_msic;
 359         }
 360
 361         msic->dcr_host = dcr_map(dn, dcr_base, dcr_len);
 362         if (!DCR_MAP_OK(msic->dcr_host)) {
 363                 printk(KERN_ERR "axon_msi: dcr_map failed for %s\n",
 364                        dn->full_name);
 365                 goto out_free_msic;
 366         }
 367
 368         msic->fifo_virt = dma_alloc_coherent(&device->dev, MSIC_FIFO_SIZE_BYTES,
 369                                              &msic->fifo_phys, GFP_KERNEL);
 370         if (!msic->fifo_virt) {
 371                 printk(KERN_ERR "axon_msi: couldn't allocate fifo for %s\n",
 372                        dn->full_name);
 373                 goto out_free_msic;
 374         }
 375
 376         virq = irq_of_parse_and_map(dn, 0);
 377         if (virq == NO_IRQ) {
 378                 printk(KERN_ERR "axon_msi: irq parse and map failed for %s\n",
 379                        dn->full_name);
 380                 goto out_free_fifo;
 381         }
 382         memset(msic->fifo_virt, 0xff, MSIC_FIFO_SIZE_BYTES);
 383
 384         /* We rely on being able to stash a virq in a u16, so limit irqs to < 65536 */
 385         msic->irq_domain = irq_domain_add_nomap(dn, 65536, &msic_host_ops, msic);
 386         if (!msic->irq_domain) {
 387                 printk(KERN_ERR "axon_msi: couldn't allocate irq_domain for %s\n",
 388                        dn->full_name);
 389                 goto out_free_fifo;
 390         }
 391
 392         irq_set_handler_data(virq, msic);
 393         irq_set_chained_handler(virq, axon_msi_cascade);
 394         pr_devel("axon_msi: irq 0x%x setup for axon_msi\n", virq);
 395
 396         /* Enable the MSIC hardware */
 397         msic_dcr_write(msic, MSIC_BASE_ADDR_HI_REG, msic->fifo_phys >> 32);
 398         msic_dcr_write(msic, MSIC_BASE_ADDR_LO_REG,
 399                                   msic->fifo_phys & 0xFFFFFFFF);
 400         msic_dcr_write(msic, MSIC_CTRL_REG,
 401                         MSIC_CTRL_IRQ_ENABLE | MSIC_CTRL_ENABLE |
 402                         MSIC_CTRL_FIFO_SIZE);
 403
 404         msic->read_offset = dcr_read(msic->dcr_host, MSIC_WRITE_OFFSET_REG)
 405                                 & MSIC_FIFO_SIZE_MASK;
 406
 407         dev_set_drvdata(&device->dev, msic);
 408
 409         ppc_md.setup_msi_irqs = axon_msi_setup_msi_irqs;
 410         ppc_md.teardown_msi_irqs = axon_msi_teardown_msi_irqs;
 411
 412         axon_msi_debug_setup(dn, msic);
 413
 414         printk(KERN_DEBUG "axon_msi: setup MSIC on %s\n", dn->full_name);
 415
 416         return 0;
 417
 418 out_free_fifo:
 419         dma_free_coherent(&device->dev, MSIC_FIFO_SIZE_BYTES, msic->fifo_virt,
 420                           msic->fifo_phys);
 421 out_free_msic:
 422         kfree(msic);
 423 out:
 424
 425         return -1;
 426 }
 427
 428 static const struct of_device_id axon_msi_device_id[] = {
 429         {
 430                 .compatible     = "ibm,axon-msic"
 431         },
 432         {}
 433 };
 434
 435 static struct platform_driver axon_msi_driver = {
 436         .probe          = axon_msi_probe,
 437         .shutdown       = axon_msi_shutdown,
 438         .driver = {
 439                 .name = "axon-msi",
 440                 .of_match_table = axon_msi_device_id,
 441         },
 442 };
 443
 444 static int __init axon_msi_init(void)
 445 {
 446         return platform_driver_register(&axon_msi_driver);
 447 }
 448 subsys_initcall(axon_msi_init);
 449
 450
 451 #ifdef DEBUG
 452 static int msic_set(void *data, u64 val)
 453 {
 454         struct axon_msic *msic = data;
 455         out_le32(msic->trigger, val);
 456         return 0;
 457 }
 458
 459 static int msic_get(void *data, u64 *val)
 460 {
 461         *val = 0;
 462         return 0;
 463 }
 464
 465 DEFINE_SIMPLE_ATTRIBUTE(fops_msic, msic_get, msic_set, "%llu\n");
 466
 467 void axon_msi_debug_setup(struct device_node *dn, struct axon_msic *msic)
 468 {
 469         char name[8];
 470         u64 addr;
 471
 472         addr = of_translate_address(dn, of_get_property(dn, "reg", NULL));
 473         if (addr == OF_BAD_ADDR) {
 474                 pr_devel("axon_msi: couldn't translate reg property\n");
 475                 return;
 476         }
 477
 478         msic->trigger = ioremap(addr, 0x4);
 479         if (!msic->trigger) {
 480                 pr_devel("axon_msi: ioremap failed\n");
 481                 return;
 482         }
 483
 484         snprintf(name, sizeof(name), "msic_%d", of_node_to_nid(dn));
 485
 486         if (!debugfs_create_file(name, 0600, powerpc_debugfs_root,
 487                                  msic, &fops_msic)) {
 488                 pr_devel("axon_msi: debugfs_create_file failed!\n");
 489                 return;
 490         }
 491 }
 492 #endif /* DEBUG */