1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright IBM Corp. 2020 4 * 5 * Author(s): 6 * Pierre Morel <pmorel@linux.ibm.com> 7 * 8 */ 9 10 #define KMSG_COMPONENT "zpci" 11 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt 12 13 #include <linux/kernel.h> 14 #include <linux/slab.h> 15 #include <linux/err.h> 16 #include <linux/export.h> 17 #include <linux/delay.h> 18 #include <linux/seq_file.h> 19 #include <linux/jump_label.h> 20 #include <linux/pci.h> 21 #include <linux/printk.h> 22 23 #include <asm/pci_clp.h> 24 #include <asm/pci_dma.h> 25 26 #include "pci_bus.h" 27 #include "pci_iov.h" 28 29 static LIST_HEAD(zbus_list); 30 static DEFINE_MUTEX(zbus_list_lock); 31 static int zpci_nb_devices; 32 33 /* zpci_bus_prepare_device - Prepare a zPCI function for scanning 34 * @zdev: the zPCI function to be prepared 35 * 36 * The PCI resources for the function are set up and added to its zbus and the 37 * function is enabled. The function must be added to a zbus which must have 38 * a PCI bus created. If an error occurs the zPCI function is not enabled. 39 * 40 * Return: 0 on success, an error code otherwise 41 */ 42 static int zpci_bus_prepare_device(struct zpci_dev *zdev) 43 { 44 struct resource_entry *window, *n; 45 struct resource *res; 46 int rc; 47 48 if (!zdev_enabled(zdev)) { 49 rc = zpci_enable_device(zdev); 50 if (rc) 51 return rc; 52 rc = zpci_dma_init_device(zdev); 53 if (rc) { 54 zpci_disable_device(zdev); 55 return rc; 56 } 57 } 58 59 if (!zdev->has_resources) { 60 zpci_setup_bus_resources(zdev, &zdev->zbus->resources); 61 resource_list_for_each_entry_safe(window, n, &zdev->zbus->resources) { 62 res = window->res; 63 pci_bus_add_resource(zdev->zbus->bus, res, 0); 64 } 65 } 66 67 return 0; 68 } 69 70 /* zpci_bus_scan_device - Scan a single device adding it to the PCI core 71 * @zdev: the zdev to be scanned 72 * 73 * Scans the PCI function making it available to the common PCI code. 74 * 75 * Return: 0 on success, an error value otherwise 76 */ 77 int zpci_bus_scan_device(struct zpci_dev *zdev) 78 { 79 struct pci_dev *pdev; 80 int rc; 81 82 rc = zpci_bus_prepare_device(zdev); 83 if (rc) 84 return rc; 85 86 pdev = pci_scan_single_device(zdev->zbus->bus, zdev->devfn); 87 if (!pdev) 88 return -ENODEV; 89 90 pci_bus_add_device(pdev); 91 pci_lock_rescan_remove(); 92 pci_bus_add_devices(zdev->zbus->bus); 93 pci_unlock_rescan_remove(); 94 95 return 0; 96 } 97 98 /* zpci_bus_remove_device - Removes the given zdev from the PCI core 99 * @zdev: the zdev to be removed from the PCI core 100 * @set_error: if true the device's error state is set to permanent failure 101 * 102 * Sets a zPCI device to a configured but offline state; the zPCI 103 * device is still accessible through its hotplug slot and the zPCI 104 * API but is removed from the common code PCI bus, making it 105 * no longer available to drivers. 106 */ 107 void zpci_bus_remove_device(struct zpci_dev *zdev, bool set_error) 108 { 109 struct zpci_bus *zbus = zdev->zbus; 110 struct pci_dev *pdev; 111 112 if (!zdev->zbus->bus) 113 return; 114 115 pdev = pci_get_slot(zbus->bus, zdev->devfn); 116 if (pdev) { 117 if (set_error) 118 pdev->error_state = pci_channel_io_perm_failure; 119 if (pdev->is_virtfn) { 120 zpci_iov_remove_virtfn(pdev, zdev->vfn); 121 /* balance pci_get_slot */ 122 pci_dev_put(pdev); 123 return; 124 } 125 pci_stop_and_remove_bus_device_locked(pdev); 126 /* balance pci_get_slot */ 127 pci_dev_put(pdev); 128 } 129 } 130 131 /* zpci_bus_scan_bus - Scan all configured zPCI functions on the bus 132 * @zbus: the zbus to be scanned 133 * 134 * Enables and scans all PCI functions on the bus making them available to the 135 * common PCI code. If there is no function 0 on the zbus nothing is scanned. If 136 * a function does not have a slot yet because it was added to the zbus before 137 * function 0 the slot is created. If a PCI function fails to be initialized 138 * an error will be returned but attempts will still be made for all other 139 * functions on the bus. 140 * 141 * Return: 0 on success, an error value otherwise 142 */ 143 int zpci_bus_scan_bus(struct zpci_bus *zbus) 144 { 145 struct zpci_dev *zdev; 146 int devfn, rc, ret = 0; 147 148 for (devfn = 0; devfn < ZPCI_FUNCTIONS_PER_BUS; devfn++) { 149 zdev = zbus->function[devfn]; 150 if (zdev && zdev->state == ZPCI_FN_STATE_CONFIGURED) { 151 rc = zpci_bus_prepare_device(zdev); 152 if (rc) 153 ret = -EIO; 154 } 155 } 156 157 pci_lock_rescan_remove(); 158 pci_scan_child_bus(zbus->bus); 159 pci_bus_add_devices(zbus->bus); 160 pci_unlock_rescan_remove(); 161 162 return ret; 163 } 164 165 /* zpci_bus_scan_busses - Scan all registered busses 166 * 167 * Scan all available zbusses 168 * 169 */ 170 void zpci_bus_scan_busses(void) 171 { 172 struct zpci_bus *zbus = NULL; 173 174 mutex_lock(&zbus_list_lock); 175 list_for_each_entry(zbus, &zbus_list, bus_next) { 176 zpci_bus_scan_bus(zbus); 177 cond_resched(); 178 } 179 mutex_unlock(&zbus_list_lock); 180 } 181 182 /* zpci_bus_create_pci_bus - Create the PCI bus associated with this zbus 183 * @zbus: the zbus holding the zdevices 184 * @fr: PCI root function that will determine the bus's domain, and bus speeed 185 * @ops: the pci operations 186 * 187 * The PCI function @fr determines the domain (its UID), multifunction property 188 * and maximum bus speed of the entire bus. 189 * 190 * Return: 0 on success, an error code otherwise 191 */ 192 static int zpci_bus_create_pci_bus(struct zpci_bus *zbus, struct zpci_dev *fr, struct pci_ops *ops) 193 { 194 struct pci_bus *bus; 195 int domain; 196 197 domain = zpci_alloc_domain((u16)fr->uid); 198 if (domain < 0) 199 return domain; 200 201 zbus->domain_nr = domain; 202 zbus->multifunction = fr->rid_available; 203 zbus->max_bus_speed = fr->max_bus_speed; 204 205 /* 206 * Note that the zbus->resources are taken over and zbus->resources 207 * is empty after a successful call 208 */ 209 bus = pci_create_root_bus(NULL, ZPCI_BUS_NR, ops, zbus, &zbus->resources); 210 if (!bus) { 211 zpci_free_domain(zbus->domain_nr); 212 return -EFAULT; 213 } 214 215 zbus->bus = bus; 216 pci_bus_add_devices(bus); 217 218 return 0; 219 } 220 221 static void zpci_bus_release(struct kref *kref) 222 { 223 struct zpci_bus *zbus = container_of(kref, struct zpci_bus, kref); 224 225 if (zbus->bus) { 226 pci_lock_rescan_remove(); 227 pci_stop_root_bus(zbus->bus); 228 229 zpci_free_domain(zbus->domain_nr); 230 pci_free_resource_list(&zbus->resources); 231 232 pci_remove_root_bus(zbus->bus); 233 pci_unlock_rescan_remove(); 234 } 235 236 mutex_lock(&zbus_list_lock); 237 list_del(&zbus->bus_next); 238 mutex_unlock(&zbus_list_lock); 239 kfree(zbus); 240 } 241 242 static void zpci_bus_put(struct zpci_bus *zbus) 243 { 244 kref_put(&zbus->kref, zpci_bus_release); 245 } 246 247 static struct zpci_bus *zpci_bus_get(int pchid) 248 { 249 struct zpci_bus *zbus; 250 251 mutex_lock(&zbus_list_lock); 252 list_for_each_entry(zbus, &zbus_list, bus_next) { 253 if (pchid == zbus->pchid) { 254 kref_get(&zbus->kref); 255 goto out_unlock; 256 } 257 } 258 zbus = NULL; 259 out_unlock: 260 mutex_unlock(&zbus_list_lock); 261 return zbus; 262 } 263 264 static struct zpci_bus *zpci_bus_alloc(int pchid) 265 { 266 struct zpci_bus *zbus; 267 268 zbus = kzalloc(sizeof(*zbus), GFP_KERNEL); 269 if (!zbus) 270 return NULL; 271 272 zbus->pchid = pchid; 273 INIT_LIST_HEAD(&zbus->bus_next); 274 mutex_lock(&zbus_list_lock); 275 list_add_tail(&zbus->bus_next, &zbus_list); 276 mutex_unlock(&zbus_list_lock); 277 278 kref_init(&zbus->kref); 279 INIT_LIST_HEAD(&zbus->resources); 280 281 zbus->bus_resource.start = 0; 282 zbus->bus_resource.end = ZPCI_BUS_NR; 283 zbus->bus_resource.flags = IORESOURCE_BUS; 284 pci_add_resource(&zbus->resources, &zbus->bus_resource); 285 286 return zbus; 287 } 288 289 void pcibios_bus_add_device(struct pci_dev *pdev) 290 { 291 struct zpci_dev *zdev = to_zpci(pdev); 292 293 /* 294 * With pdev->no_vf_scan the common PCI probing code does not 295 * perform PF/VF linking. 296 */ 297 if (zdev->vfn) { 298 zpci_iov_setup_virtfn(zdev->zbus, pdev, zdev->vfn); 299 pdev->no_command_memory = 1; 300 } 301 } 302 303 static int zpci_bus_add_device(struct zpci_bus *zbus, struct zpci_dev *zdev) 304 { 305 int rc = -EINVAL; 306 307 if (zbus->function[zdev->devfn]) { 308 pr_err("devfn %04x is already assigned\n", zdev->devfn); 309 return rc; 310 } 311 312 zdev->zbus = zbus; 313 zbus->function[zdev->devfn] = zdev; 314 zpci_nb_devices++; 315 316 if (zbus->multifunction && !zdev->rid_available) { 317 WARN_ONCE(1, "rid_available not set for multifunction\n"); 318 goto error; 319 } 320 rc = zpci_init_slot(zdev); 321 if (rc) 322 goto error; 323 zdev->has_hp_slot = 1; 324 325 return 0; 326 327 error: 328 zbus->function[zdev->devfn] = NULL; 329 zdev->zbus = NULL; 330 zpci_nb_devices--; 331 return rc; 332 } 333 334 int zpci_bus_device_register(struct zpci_dev *zdev, struct pci_ops *ops) 335 { 336 struct zpci_bus *zbus = NULL; 337 int rc = -EBADF; 338 339 if (zpci_nb_devices == ZPCI_NR_DEVICES) { 340 pr_warn("Adding PCI function %08x failed because the configured limit of %d is reached\n", 341 zdev->fid, ZPCI_NR_DEVICES); 342 return -ENOSPC; 343 } 344 345 if (zdev->devfn >= ZPCI_FUNCTIONS_PER_BUS) 346 return -EINVAL; 347 348 if (!s390_pci_no_rid && zdev->rid_available) 349 zbus = zpci_bus_get(zdev->pchid); 350 351 if (!zbus) { 352 zbus = zpci_bus_alloc(zdev->pchid); 353 if (!zbus) 354 return -ENOMEM; 355 } 356 357 if (!zbus->bus) { 358 /* The UID of the first PCI function registered with a zpci_bus 359 * is used as the domain number for that bus. Currently there 360 * is exactly one zpci_bus per domain. 361 */ 362 rc = zpci_bus_create_pci_bus(zbus, zdev, ops); 363 if (rc) 364 goto error; 365 } 366 367 rc = zpci_bus_add_device(zbus, zdev); 368 if (rc) 369 goto error; 370 371 return 0; 372 373 error: 374 pr_err("Adding PCI function %08x failed\n", zdev->fid); 375 zpci_bus_put(zbus); 376 return rc; 377 } 378 379 void zpci_bus_device_unregister(struct zpci_dev *zdev) 380 { 381 struct zpci_bus *zbus = zdev->zbus; 382 383 zpci_nb_devices--; 384 zbus->function[zdev->devfn] = NULL; 385 zpci_bus_put(zbus); 386 } 387