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 */
zpci_bus_prepare_device(struct zpci_dev * zdev)42 static int zpci_bus_prepare_device(struct zpci_dev *zdev)
43 {
44 int rc, i;
45
46 if (!zdev_enabled(zdev)) {
47 rc = zpci_enable_device(zdev);
48 if (rc)
49 return rc;
50 rc = zpci_dma_init_device(zdev);
51 if (rc) {
52 zpci_disable_device(zdev);
53 return rc;
54 }
55 }
56
57 if (!zdev->has_resources) {
58 zpci_setup_bus_resources(zdev);
59 for (i = 0; i < PCI_STD_NUM_BARS; i++) {
60 if (zdev->bars[i].res)
61 pci_bus_add_resource(zdev->zbus->bus, zdev->bars[i].res, 0);
62 }
63 }
64
65 return 0;
66 }
67
68 /* zpci_bus_scan_device - Scan a single device adding it to the PCI core
69 * @zdev: the zdev to be scanned
70 *
71 * Scans the PCI function making it available to the common PCI code.
72 *
73 * Return: 0 on success, an error value otherwise
74 */
zpci_bus_scan_device(struct zpci_dev * zdev)75 int zpci_bus_scan_device(struct zpci_dev *zdev)
76 {
77 struct pci_dev *pdev;
78 int rc;
79
80 rc = zpci_bus_prepare_device(zdev);
81 if (rc)
82 return rc;
83
84 pdev = pci_scan_single_device(zdev->zbus->bus, zdev->devfn);
85 if (!pdev)
86 return -ENODEV;
87
88 pci_lock_rescan_remove();
89 pci_bus_add_device(pdev);
90 pci_unlock_rescan_remove();
91
92 return 0;
93 }
94
95 /* zpci_bus_remove_device - Removes the given zdev from the PCI core
96 * @zdev: the zdev to be removed from the PCI core
97 * @set_error: if true the device's error state is set to permanent failure
98 *
99 * Sets a zPCI device to a configured but offline state; the zPCI
100 * device is still accessible through its hotplug slot and the zPCI
101 * API but is removed from the common code PCI bus, making it
102 * no longer available to drivers.
103 */
zpci_bus_remove_device(struct zpci_dev * zdev,bool set_error)104 void zpci_bus_remove_device(struct zpci_dev *zdev, bool set_error)
105 {
106 struct zpci_bus *zbus = zdev->zbus;
107 struct pci_dev *pdev;
108
109 if (!zdev->zbus->bus)
110 return;
111
112 pdev = pci_get_slot(zbus->bus, zdev->devfn);
113 if (pdev) {
114 if (set_error)
115 pdev->error_state = pci_channel_io_perm_failure;
116 if (pdev->is_virtfn) {
117 zpci_iov_remove_virtfn(pdev, zdev->vfn);
118 /* balance pci_get_slot */
119 pci_dev_put(pdev);
120 return;
121 }
122 pci_stop_and_remove_bus_device_locked(pdev);
123 /* balance pci_get_slot */
124 pci_dev_put(pdev);
125 }
126 }
127
128 /* zpci_bus_scan_bus - Scan all configured zPCI functions on the bus
129 * @zbus: the zbus to be scanned
130 *
131 * Enables and scans all PCI functions on the bus making them available to the
132 * common PCI code. If a PCI function fails to be initialized an error will be
133 * returned but attempts will still be made for all other functions on the bus.
134 *
135 * Return: 0 on success, an error value otherwise
136 */
zpci_bus_scan_bus(struct zpci_bus * zbus)137 int zpci_bus_scan_bus(struct zpci_bus *zbus)
138 {
139 struct zpci_dev *zdev;
140 int devfn, rc, ret = 0;
141
142 for (devfn = 0; devfn < ZPCI_FUNCTIONS_PER_BUS; devfn++) {
143 zdev = zbus->function[devfn];
144 if (zdev && zdev->state == ZPCI_FN_STATE_CONFIGURED) {
145 rc = zpci_bus_prepare_device(zdev);
146 if (rc)
147 ret = -EIO;
148 }
149 }
150
151 pci_lock_rescan_remove();
152 pci_scan_child_bus(zbus->bus);
153 pci_bus_add_devices(zbus->bus);
154 pci_unlock_rescan_remove();
155
156 return ret;
157 }
158
159 /* zpci_bus_scan_busses - Scan all registered busses
160 *
161 * Scan all available zbusses
162 *
163 */
zpci_bus_scan_busses(void)164 void zpci_bus_scan_busses(void)
165 {
166 struct zpci_bus *zbus = NULL;
167
168 mutex_lock(&zbus_list_lock);
169 list_for_each_entry(zbus, &zbus_list, bus_next) {
170 zpci_bus_scan_bus(zbus);
171 cond_resched();
172 }
173 mutex_unlock(&zbus_list_lock);
174 }
175
176 /* zpci_bus_create_pci_bus - Create the PCI bus associated with this zbus
177 * @zbus: the zbus holding the zdevices
178 * @fr: PCI root function that will determine the bus's domain, and bus speeed
179 * @ops: the pci operations
180 *
181 * The PCI function @fr determines the domain (its UID), multifunction property
182 * and maximum bus speed of the entire bus.
183 *
184 * Return: 0 on success, an error code otherwise
185 */
zpci_bus_create_pci_bus(struct zpci_bus * zbus,struct zpci_dev * fr,struct pci_ops * ops)186 static int zpci_bus_create_pci_bus(struct zpci_bus *zbus, struct zpci_dev *fr, struct pci_ops *ops)
187 {
188 struct pci_bus *bus;
189 int domain;
190
191 domain = zpci_alloc_domain((u16)fr->uid);
192 if (domain < 0)
193 return domain;
194
195 zbus->domain_nr = domain;
196 zbus->multifunction = fr->rid_available;
197 zbus->max_bus_speed = fr->max_bus_speed;
198
199 /*
200 * Note that the zbus->resources are taken over and zbus->resources
201 * is empty after a successful call
202 */
203 bus = pci_create_root_bus(NULL, ZPCI_BUS_NR, ops, zbus, &zbus->resources);
204 if (!bus) {
205 zpci_free_domain(zbus->domain_nr);
206 return -EFAULT;
207 }
208
209 zbus->bus = bus;
210
211 return 0;
212 }
213
zpci_bus_release(struct kref * kref)214 static void zpci_bus_release(struct kref *kref)
215 {
216 struct zpci_bus *zbus = container_of(kref, struct zpci_bus, kref);
217
218 if (zbus->bus) {
219 pci_lock_rescan_remove();
220 pci_stop_root_bus(zbus->bus);
221
222 zpci_free_domain(zbus->domain_nr);
223 pci_free_resource_list(&zbus->resources);
224
225 pci_remove_root_bus(zbus->bus);
226 pci_unlock_rescan_remove();
227 }
228
229 mutex_lock(&zbus_list_lock);
230 list_del(&zbus->bus_next);
231 mutex_unlock(&zbus_list_lock);
232 kfree(zbus);
233 }
234
zpci_bus_put(struct zpci_bus * zbus)235 static void zpci_bus_put(struct zpci_bus *zbus)
236 {
237 kref_put(&zbus->kref, zpci_bus_release);
238 }
239
zpci_bus_get(int pchid)240 static struct zpci_bus *zpci_bus_get(int pchid)
241 {
242 struct zpci_bus *zbus;
243
244 mutex_lock(&zbus_list_lock);
245 list_for_each_entry(zbus, &zbus_list, bus_next) {
246 if (pchid == zbus->pchid) {
247 kref_get(&zbus->kref);
248 goto out_unlock;
249 }
250 }
251 zbus = NULL;
252 out_unlock:
253 mutex_unlock(&zbus_list_lock);
254 return zbus;
255 }
256
zpci_bus_alloc(int pchid)257 static struct zpci_bus *zpci_bus_alloc(int pchid)
258 {
259 struct zpci_bus *zbus;
260
261 zbus = kzalloc(sizeof(*zbus), GFP_KERNEL);
262 if (!zbus)
263 return NULL;
264
265 zbus->pchid = pchid;
266 INIT_LIST_HEAD(&zbus->bus_next);
267 mutex_lock(&zbus_list_lock);
268 list_add_tail(&zbus->bus_next, &zbus_list);
269 mutex_unlock(&zbus_list_lock);
270
271 kref_init(&zbus->kref);
272 INIT_LIST_HEAD(&zbus->resources);
273
274 zbus->bus_resource.start = 0;
275 zbus->bus_resource.end = ZPCI_BUS_NR;
276 zbus->bus_resource.flags = IORESOURCE_BUS;
277 pci_add_resource(&zbus->resources, &zbus->bus_resource);
278
279 return zbus;
280 }
281
pcibios_bus_add_device(struct pci_dev * pdev)282 void pcibios_bus_add_device(struct pci_dev *pdev)
283 {
284 struct zpci_dev *zdev = to_zpci(pdev);
285
286 /*
287 * With pdev->no_vf_scan the common PCI probing code does not
288 * perform PF/VF linking.
289 */
290 if (zdev->vfn) {
291 zpci_iov_setup_virtfn(zdev->zbus, pdev, zdev->vfn);
292 pdev->no_command_memory = 1;
293 }
294 }
295
zpci_bus_add_device(struct zpci_bus * zbus,struct zpci_dev * zdev)296 static int zpci_bus_add_device(struct zpci_bus *zbus, struct zpci_dev *zdev)
297 {
298 int rc = -EINVAL;
299
300 if (zbus->function[zdev->devfn]) {
301 pr_err("devfn %04x is already assigned\n", zdev->devfn);
302 return rc;
303 }
304
305 zdev->zbus = zbus;
306 zbus->function[zdev->devfn] = zdev;
307 zpci_nb_devices++;
308
309 if (zbus->multifunction && !zdev->rid_available) {
310 WARN_ONCE(1, "rid_available not set for multifunction\n");
311 goto error;
312 }
313 rc = zpci_init_slot(zdev);
314 if (rc)
315 goto error;
316 zdev->has_hp_slot = 1;
317
318 return 0;
319
320 error:
321 zbus->function[zdev->devfn] = NULL;
322 zdev->zbus = NULL;
323 zpci_nb_devices--;
324 return rc;
325 }
326
zpci_bus_device_register(struct zpci_dev * zdev,struct pci_ops * ops)327 int zpci_bus_device_register(struct zpci_dev *zdev, struct pci_ops *ops)
328 {
329 struct zpci_bus *zbus = NULL;
330 int rc = -EBADF;
331
332 if (zpci_nb_devices == ZPCI_NR_DEVICES) {
333 pr_warn("Adding PCI function %08x failed because the configured limit of %d is reached\n",
334 zdev->fid, ZPCI_NR_DEVICES);
335 return -ENOSPC;
336 }
337
338 if (zdev->devfn >= ZPCI_FUNCTIONS_PER_BUS)
339 return -EINVAL;
340
341 if (!s390_pci_no_rid && zdev->rid_available)
342 zbus = zpci_bus_get(zdev->pchid);
343
344 if (!zbus) {
345 zbus = zpci_bus_alloc(zdev->pchid);
346 if (!zbus)
347 return -ENOMEM;
348 }
349
350 if (!zbus->bus) {
351 /* The UID of the first PCI function registered with a zpci_bus
352 * is used as the domain number for that bus. Currently there
353 * is exactly one zpci_bus per domain.
354 */
355 rc = zpci_bus_create_pci_bus(zbus, zdev, ops);
356 if (rc)
357 goto error;
358 }
359
360 rc = zpci_bus_add_device(zbus, zdev);
361 if (rc)
362 goto error;
363
364 return 0;
365
366 error:
367 pr_err("Adding PCI function %08x failed\n", zdev->fid);
368 zpci_bus_put(zbus);
369 return rc;
370 }
371
zpci_bus_device_unregister(struct zpci_dev * zdev)372 void zpci_bus_device_unregister(struct zpci_dev *zdev)
373 {
374 struct zpci_bus *zbus = zdev->zbus;
375
376 zpci_nb_devices--;
377 zbus->function[zdev->devfn] = NULL;
378 zpci_bus_put(zbus);
379 }
380