drivers/cxl/acpi.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* Copyright(c) 2021 Intel Corporation. All rights reserved. */
   3 #include <linux/platform_device.h>
   4 #include <linux/module.h>
   5 #include <linux/device.h>
   6 #include <linux/kernel.h>
   7 #include <linux/acpi.h>
   8 #include <linux/pci.h>
   9 #include "cxl.h"
  10
  11 static struct acpi_table_header *acpi_cedt;
  12
  13 /* Encode defined in CXL 2.0 8.2.5.12.7 HDM Decoder Control Register */
  14 #define CFMWS_INTERLEAVE_WAYS(x)        (1 << (x)->interleave_ways)
  15 #define CFMWS_INTERLEAVE_GRANULARITY(x) ((x)->granularity + 8)
  16
  17 static unsigned long cfmws_to_decoder_flags(int restrictions)
  18 {
  19         unsigned long flags = 0;
  20
  21         if (restrictions & ACPI_CEDT_CFMWS_RESTRICT_TYPE2)
  22                 flags |= CXL_DECODER_F_TYPE2;
  23         if (restrictions & ACPI_CEDT_CFMWS_RESTRICT_TYPE3)
  24                 flags |= CXL_DECODER_F_TYPE3;
  25         if (restrictions & ACPI_CEDT_CFMWS_RESTRICT_VOLATILE)
  26                 flags |= CXL_DECODER_F_RAM;
  27         if (restrictions & ACPI_CEDT_CFMWS_RESTRICT_PMEM)
  28                 flags |= CXL_DECODER_F_PMEM;
  29         if (restrictions & ACPI_CEDT_CFMWS_RESTRICT_FIXED)
  30                 flags |= CXL_DECODER_F_LOCK;
  31
  32         return flags;
  33 }
  34
  35 static int cxl_acpi_cfmws_verify(struct device *dev,
  36                                  struct acpi_cedt_cfmws *cfmws)
  37 {
  38         int expected_len;
  39
  40         if (cfmws->interleave_arithmetic != ACPI_CEDT_CFMWS_ARITHMETIC_MODULO) {
  41                 dev_err(dev, "CFMWS Unsupported Interleave Arithmetic\n");
  42                 return -EINVAL;
  43         }
  44
  45         if (!IS_ALIGNED(cfmws->base_hpa, SZ_256M)) {
  46                 dev_err(dev, "CFMWS Base HPA not 256MB aligned\n");
  47                 return -EINVAL;
  48         }
  49
  50         if (!IS_ALIGNED(cfmws->window_size, SZ_256M)) {
  51                 dev_err(dev, "CFMWS Window Size not 256MB aligned\n");
  52                 return -EINVAL;
  53         }
  54
  55         expected_len = struct_size((cfmws), interleave_targets,
  56                                    CFMWS_INTERLEAVE_WAYS(cfmws));
  57
  58         if (cfmws->header.length < expected_len) {
  59                 dev_err(dev, "CFMWS length %d less than expected %d\n",
  60                         cfmws->header.length, expected_len);
  61                 return -EINVAL;
  62         }
  63
  64         if (cfmws->header.length > expected_len)
  65                 dev_dbg(dev, "CFMWS length %d greater than expected %d\n",
  66                         cfmws->header.length, expected_len);
  67
  68         return 0;
  69 }
  70
  71 static void cxl_add_cfmws_decoders(struct device *dev,
  72                                    struct cxl_port *root_port)
  73 {
  74         struct acpi_cedt_cfmws *cfmws;
  75         struct cxl_decoder *cxld;
  76         acpi_size len, cur = 0;
  77         void *cedt_subtable;
  78         unsigned long flags;
  79         int rc;
  80
  81         len = acpi_cedt->length - sizeof(*acpi_cedt);
  82         cedt_subtable = acpi_cedt + 1;
  83
  84         while (cur < len) {
  85                 struct acpi_cedt_header *c = cedt_subtable + cur;
  86
  87                 if (c->type != ACPI_CEDT_TYPE_CFMWS) {
  88                         cur += c->length;
  89                         continue;
  90                 }
  91
  92                 cfmws = cedt_subtable + cur;
  93
  94                 if (cfmws->header.length < sizeof(*cfmws)) {
  95                         dev_warn_once(dev,
  96                                       "CFMWS entry skipped:invalid length:%u\n",
  97                                       cfmws->header.length);
  98                         cur += c->length;
  99                         continue;
 100                 }
 101
 102                 rc = cxl_acpi_cfmws_verify(dev, cfmws);
 103                 if (rc) {
 104                         dev_err(dev, "CFMWS range %#llx-%#llx not registered\n",
 105                                 cfmws->base_hpa, cfmws->base_hpa +
 106                                 cfmws->window_size - 1);
 107                         cur += c->length;
 108                         continue;
 109                 }
 110
 111                 flags = cfmws_to_decoder_flags(cfmws->restrictions);
 112                 cxld = devm_cxl_add_decoder(dev, root_port,
 113                                             CFMWS_INTERLEAVE_WAYS(cfmws),
 114                                             cfmws->base_hpa, cfmws->window_size,
 115                                             CFMWS_INTERLEAVE_WAYS(cfmws),
 116                                             CFMWS_INTERLEAVE_GRANULARITY(cfmws),
 117                                             CXL_DECODER_EXPANDER,
 118                                             flags);
 119
 120                 if (IS_ERR(cxld)) {
 121                         dev_err(dev, "Failed to add decoder for %#llx-%#llx\n",
 122                                 cfmws->base_hpa, cfmws->base_hpa +
 123                                 cfmws->window_size - 1);
 124                 } else {
 125                         dev_dbg(dev, "add: %s range %#llx-%#llx\n",
 126                                 dev_name(&cxld->dev), cfmws->base_hpa,
 127                                  cfmws->base_hpa + cfmws->window_size - 1);
 128                 }
 129                 cur += c->length;
 130         }
 131 }
 132
 133 static struct acpi_cedt_chbs *cxl_acpi_match_chbs(struct device *dev, u32 uid)
 134 {
 135         struct acpi_cedt_chbs *chbs, *chbs_match = NULL;
 136         acpi_size len, cur = 0;
 137         void *cedt_subtable;
 138
 139         len = acpi_cedt->length - sizeof(*acpi_cedt);
 140         cedt_subtable = acpi_cedt + 1;
 141
 142         while (cur < len) {
 143                 struct acpi_cedt_header *c = cedt_subtable + cur;
 144
 145                 if (c->type != ACPI_CEDT_TYPE_CHBS) {
 146                         cur += c->length;
 147                         continue;
 148                 }
 149
 150                 chbs = cedt_subtable + cur;
 151
 152                 if (chbs->header.length < sizeof(*chbs)) {
 153                         dev_warn_once(dev,
 154                                       "CHBS entry skipped: invalid length:%u\n",
 155                                       chbs->header.length);
 156                         cur += c->length;
 157                         continue;
 158                 }
 159
 160                 if (chbs->uid != uid) {
 161                         cur += c->length;
 162                         continue;
 163                 }
 164
 165                 if (chbs_match) {
 166                         dev_warn_once(dev,
 167                                       "CHBS entry skipped: duplicate UID:%u\n",
 168                                       uid);
 169                         cur += c->length;
 170                         continue;
 171                 }
 172
 173                 chbs_match = chbs;
 174                 cur += c->length;
 175         }
 176
 177         return chbs_match ? chbs_match : ERR_PTR(-ENODEV);
 178 }
 179
 180 static resource_size_t get_chbcr(struct acpi_cedt_chbs *chbs)
 181 {
 182         return IS_ERR(chbs) ? CXL_RESOURCE_NONE : chbs->base;
 183 }
 184
 185 struct cxl_walk_context {
 186         struct device *dev;
 187         struct pci_bus *root;
 188         struct cxl_port *port;
 189         int error;
 190         int count;
 191 };
 192
 193 static int match_add_root_ports(struct pci_dev *pdev, void *data)
 194 {
 195         struct cxl_walk_context *ctx = data;
 196         struct pci_bus *root_bus = ctx->root;
 197         struct cxl_port *port = ctx->port;
 198         int type = pci_pcie_type(pdev);
 199         struct device *dev = ctx->dev;
 200         u32 lnkcap, port_num;
 201         int rc;
 202
 203         if (pdev->bus != root_bus)
 204                 return 0;
 205         if (!pci_is_pcie(pdev))
 206                 return 0;
 207         if (type != PCI_EXP_TYPE_ROOT_PORT)
 208                 return 0;
 209         if (pci_read_config_dword(pdev, pci_pcie_cap(pdev) + PCI_EXP_LNKCAP,
 210                                   &lnkcap) != PCIBIOS_SUCCESSFUL)
 211                 return 0;
 212
 213         /* TODO walk DVSEC to find component register base */
 214         port_num = FIELD_GET(PCI_EXP_LNKCAP_PN, lnkcap);
 215         rc = cxl_add_dport(port, &pdev->dev, port_num, CXL_RESOURCE_NONE);
 216         if (rc) {
 217                 ctx->error = rc;
 218                 return rc;
 219         }
 220         ctx->count++;
 221
 222         dev_dbg(dev, "add dport%d: %s\n", port_num, dev_name(&pdev->dev));
 223
 224         return 0;
 225 }
 226
 227 static struct cxl_dport *find_dport_by_dev(struct cxl_port *port, struct device *dev)
 228 {
 229         struct cxl_dport *dport;
 230
 231         device_lock(&port->dev);
 232         list_for_each_entry(dport, &port->dports, list)
 233                 if (dport->dport == dev) {
 234                         device_unlock(&port->dev);
 235                         return dport;
 236                 }
 237
 238         device_unlock(&port->dev);
 239         return NULL;
 240 }
 241
 242 static struct acpi_device *to_cxl_host_bridge(struct device *dev)
 243 {
 244         struct acpi_device *adev = to_acpi_device(dev);
 245
 246         if (!acpi_pci_find_root(adev->handle))
 247                 return NULL;
 248
 249         if (strcmp(acpi_device_hid(adev), "ACPI0016") == 0)
 250                 return adev;
 251         return NULL;
 252 }
 253
 254 /*
 255  * A host bridge is a dport to a CFMWS decode and it is a uport to the
 256  * dport (PCIe Root Ports) in the host bridge.
 257  */
 258 static int add_host_bridge_uport(struct device *match, void *arg)
 259 {
 260         struct acpi_device *bridge = to_cxl_host_bridge(match);
 261         struct cxl_port *root_port = arg;
 262         struct device *host = root_port->dev.parent;
 263         struct acpi_pci_root *pci_root;
 264         struct cxl_walk_context ctx;
 265         struct cxl_decoder *cxld;
 266         struct cxl_dport *dport;
 267         struct cxl_port *port;
 268
 269         if (!bridge)
 270                 return 0;
 271
 272         dport = find_dport_by_dev(root_port, match);
 273         if (!dport) {
 274                 dev_dbg(host, "host bridge expected and not found\n");
 275                 return -ENODEV;
 276         }
 277
 278         port = devm_cxl_add_port(host, match, dport->component_reg_phys,
 279                                  root_port);
 280         if (IS_ERR(port))
 281                 return PTR_ERR(port);
 282         dev_dbg(host, "%s: add: %s\n", dev_name(match), dev_name(&port->dev));
 283
 284         /*
 285          * Note that this lookup already succeeded in
 286          * to_cxl_host_bridge(), so no need to check for failure here
 287          */
 288         pci_root = acpi_pci_find_root(bridge->handle);
 289         ctx = (struct cxl_walk_context){
 290                 .dev = host,
 291                 .root = pci_root->bus,
 292                 .port = port,
 293         };
 294         pci_walk_bus(pci_root->bus, match_add_root_ports, &ctx);
 295
 296         if (ctx.count == 0)
 297                 return -ENODEV;
 298         if (ctx.error)
 299                 return ctx.error;
 300
 301         /* TODO: Scan CHBCR for HDM Decoder resources */
 302
 303         /*
 304          * In the single-port host-bridge case there are no HDM decoders
 305          * in the CHBCR and a 1:1 passthrough decode is implied.
 306          */
 307         if (ctx.count == 1) {
 308                 cxld = devm_cxl_add_passthrough_decoder(host, port);
 309                 if (IS_ERR(cxld))
 310                         return PTR_ERR(cxld);
 311
 312                 dev_dbg(host, "add: %s\n", dev_name(&cxld->dev));
 313         }
 314
 315         return 0;
 316 }
 317
 318 static int add_host_bridge_dport(struct device *match, void *arg)
 319 {
 320         int rc;
 321         acpi_status status;
 322         unsigned long long uid;
 323         struct acpi_cedt_chbs *chbs;
 324         struct cxl_port *root_port = arg;
 325         struct device *host = root_port->dev.parent;
 326         struct acpi_device *bridge = to_cxl_host_bridge(match);
 327
 328         if (!bridge)
 329                 return 0;
 330
 331         status = acpi_evaluate_integer(bridge->handle, METHOD_NAME__UID, NULL,
 332                                        &uid);
 333         if (status != AE_OK) {
 334                 dev_err(host, "unable to retrieve _UID of %s\n",
 335                         dev_name(match));
 336                 return -ENODEV;
 337         }
 338
 339         chbs = cxl_acpi_match_chbs(host, uid);
 340         if (IS_ERR(chbs))
 341                 dev_dbg(host, "No CHBS found for Host Bridge: %s\n",
 342                         dev_name(match));
 343
 344         rc = cxl_add_dport(root_port, match, uid, get_chbcr(chbs));
 345         if (rc) {
 346                 dev_err(host, "failed to add downstream port: %s\n",
 347                         dev_name(match));
 348                 return rc;
 349         }
 350         dev_dbg(host, "add dport%llu: %s\n", uid, dev_name(match));
 351         return 0;
 352 }
 353
 354 static int add_root_nvdimm_bridge(struct device *match, void *data)
 355 {
 356         struct cxl_decoder *cxld;
 357         struct cxl_port *root_port = data;
 358         struct cxl_nvdimm_bridge *cxl_nvb;
 359         struct device *host = root_port->dev.parent;
 360
 361         if (!is_root_decoder(match))
 362                 return 0;
 363
 364         cxld = to_cxl_decoder(match);
 365         if (!(cxld->flags & CXL_DECODER_F_PMEM))
 366                 return 0;
 367
 368         cxl_nvb = devm_cxl_add_nvdimm_bridge(host, root_port);
 369         if (IS_ERR(cxl_nvb)) {
 370                 dev_dbg(host, "failed to register pmem\n");
 371                 return PTR_ERR(cxl_nvb);
 372         }
 373         dev_dbg(host, "%s: add: %s\n", dev_name(&root_port->dev),
 374                 dev_name(&cxl_nvb->dev));
 375         return 1;
 376 }
 377
 378 static int cxl_acpi_probe(struct platform_device *pdev)
 379 {
 380         int rc;
 381         acpi_status status;
 382         struct cxl_port *root_port;
 383         struct device *host = &pdev->dev;
 384         struct acpi_device *adev = ACPI_COMPANION(host);
 385
 386         root_port = devm_cxl_add_port(host, host, CXL_RESOURCE_NONE, NULL);
 387         if (IS_ERR(root_port))
 388                 return PTR_ERR(root_port);
 389         dev_dbg(host, "add: %s\n", dev_name(&root_port->dev));
 390
 391         status = acpi_get_table(ACPI_SIG_CEDT, 0, &acpi_cedt);
 392         if (ACPI_FAILURE(status))
 393                 return -ENXIO;
 394
 395         rc = bus_for_each_dev(adev->dev.bus, NULL, root_port,
 396                               add_host_bridge_dport);
 397         if (rc)
 398                 goto out;
 399
 400         cxl_add_cfmws_decoders(host, root_port);
 401
 402         /*
 403          * Root level scanned with host-bridge as dports, now scan host-bridges
 404          * for their role as CXL uports to their CXL-capable PCIe Root Ports.
 405          */
 406         rc = bus_for_each_dev(adev->dev.bus, NULL, root_port,
 407                               add_host_bridge_uport);
 408         if (rc)
 409                 goto out;
 410
 411         if (IS_ENABLED(CONFIG_CXL_PMEM))
 412                 rc = device_for_each_child(&root_port->dev, root_port,
 413                                            add_root_nvdimm_bridge);
 414
 415 out:
 416         acpi_put_table(acpi_cedt);
 417         if (rc < 0)
 418                 return rc;
 419         return 0;
 420 }
 421
 422 static const struct acpi_device_id cxl_acpi_ids[] = {
 423         { "ACPI0017", 0 },
 424         { "", 0 },
 425 };
 426 MODULE_DEVICE_TABLE(acpi, cxl_acpi_ids);
 427
 428 static struct platform_driver cxl_acpi_driver = {
 429         .probe = cxl_acpi_probe,
 430         .driver = {
 431                 .name = KBUILD_MODNAME,
 432                 .acpi_match_table = cxl_acpi_ids,
 433         },
 434 };
 435
 436 module_platform_driver(cxl_acpi_driver);
 437 MODULE_LICENSE("GPL v2");
 438 MODULE_IMPORT_NS(CXL);