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
29static LIST_HEAD(zbus_list);
30static DEFINE_MUTEX(zbus_list_lock);
31static 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 */
42static 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	}
51
52	if (!zdev->has_resources) {
53		zpci_setup_bus_resources(zdev);
54		for (i = 0; i < PCI_STD_NUM_BARS; i++) {
55			if (zdev->bars[i].res)
56				pci_bus_add_resource(zdev->zbus->bus, zdev->bars[i].res, 0);
57		}
58	}
59
60	return 0;
61}
62
63/* zpci_bus_scan_device - Scan a single device adding it to the PCI core
64 * @zdev: the zdev to be scanned
65 *
66 * Scans the PCI function making it available to the common PCI code.
67 *
68 * Return: 0 on success, an error value otherwise
69 */
70int zpci_bus_scan_device(struct zpci_dev *zdev)
71{
72	struct pci_dev *pdev;
73	int rc;
74
75	rc = zpci_bus_prepare_device(zdev);
76	if (rc)
77		return rc;
78
79	pdev = pci_scan_single_device(zdev->zbus->bus, zdev->devfn);
80	if (!pdev)
81		return -ENODEV;
82
83	pci_lock_rescan_remove();
84	pci_bus_add_device(pdev);
85	pci_unlock_rescan_remove();
86
87	return 0;
88}
89
90/* zpci_bus_remove_device - Removes the given zdev from the PCI core
91 * @zdev: the zdev to be removed from the PCI core
92 * @set_error: if true the device's error state is set to permanent failure
93 *
94 * Sets a zPCI device to a configured but offline state; the zPCI
95 * device is still accessible through its hotplug slot and the zPCI
96 * API but is removed from the common code PCI bus, making it
97 * no longer available to drivers.
98 */
99void zpci_bus_remove_device(struct zpci_dev *zdev, bool set_error)
100{
101	struct zpci_bus *zbus = zdev->zbus;
102	struct pci_dev *pdev;
103
104	if (!zdev->zbus->bus)
105		return;
106
107	pdev = pci_get_slot(zbus->bus, zdev->devfn);
108	if (pdev) {
109		if (set_error)
110			pdev->error_state = pci_channel_io_perm_failure;
111		if (pdev->is_virtfn) {
112			zpci_iov_remove_virtfn(pdev, zdev->vfn);
113			/* balance pci_get_slot */
114			pci_dev_put(pdev);
115			return;
116		}
117		pci_stop_and_remove_bus_device_locked(pdev);
118		/* balance pci_get_slot */
119		pci_dev_put(pdev);
120	}
121}
122
123/* zpci_bus_scan_bus - Scan all configured zPCI functions on the bus
124 * @zbus: the zbus to be scanned
125 *
126 * Enables and scans all PCI functions on the bus making them available to the
127 * common PCI code. If a PCI function fails to be initialized an error will be
128 * returned but attempts will still be made for all other functions on the bus.
129 *
130 * Return: 0 on success, an error value otherwise
131 */
132int zpci_bus_scan_bus(struct zpci_bus *zbus)
133{
134	struct zpci_dev *zdev;
135	int devfn, rc, ret = 0;
136
137	for (devfn = 0; devfn < ZPCI_FUNCTIONS_PER_BUS; devfn++) {
138		zdev = zbus->function[devfn];
139		if (zdev && zdev->state == ZPCI_FN_STATE_CONFIGURED) {
140			rc = zpci_bus_prepare_device(zdev);
141			if (rc)
142				ret = -EIO;
143		}
144	}
145
146	pci_lock_rescan_remove();
147	pci_scan_child_bus(zbus->bus);
148	pci_bus_add_devices(zbus->bus);
149	pci_unlock_rescan_remove();
150
151	return ret;
152}
153
154/* zpci_bus_scan_busses - Scan all registered busses
155 *
156 * Scan all available zbusses
157 *
158 */
159void zpci_bus_scan_busses(void)
160{
161	struct zpci_bus *zbus = NULL;
162
163	mutex_lock(&zbus_list_lock);
164	list_for_each_entry(zbus, &zbus_list, bus_next) {
165		zpci_bus_scan_bus(zbus);
166		cond_resched();
167	}
168	mutex_unlock(&zbus_list_lock);
169}
170
171/* zpci_bus_create_pci_bus - Create the PCI bus associated with this zbus
172 * @zbus: the zbus holding the zdevices
173 * @fr: PCI root function that will determine the bus's domain, and bus speeed
174 * @ops: the pci operations
175 *
176 * The PCI function @fr determines the domain (its UID), multifunction property
177 * and maximum bus speed of the entire bus.
178 *
179 * Return: 0 on success, an error code otherwise
180 */
181static int zpci_bus_create_pci_bus(struct zpci_bus *zbus, struct zpci_dev *fr, struct pci_ops *ops)
182{
183	struct pci_bus *bus;
184	int domain;
185
186	domain = zpci_alloc_domain((u16)fr->uid);
187	if (domain < 0)
188		return domain;
189
190	zbus->domain_nr = domain;
191	zbus->multifunction = fr->rid_available;
192	zbus->max_bus_speed = fr->max_bus_speed;
193
194	/*
195	 * Note that the zbus->resources are taken over and zbus->resources
196	 * is empty after a successful call
197	 */
198	bus = pci_create_root_bus(NULL, ZPCI_BUS_NR, ops, zbus, &zbus->resources);
199	if (!bus) {
200		zpci_free_domain(zbus->domain_nr);
201		return -EFAULT;
202	}
203
204	zbus->bus = bus;
205
206	return 0;
207}
208
209static void zpci_bus_release(struct kref *kref)
210{
211	struct zpci_bus *zbus = container_of(kref, struct zpci_bus, kref);
212
213	if (zbus->bus) {
214		pci_lock_rescan_remove();
215		pci_stop_root_bus(zbus->bus);
216
217		zpci_free_domain(zbus->domain_nr);
218		pci_free_resource_list(&zbus->resources);
219
220		pci_remove_root_bus(zbus->bus);
221		pci_unlock_rescan_remove();
222	}
223
224	mutex_lock(&zbus_list_lock);
225	list_del(&zbus->bus_next);
226	mutex_unlock(&zbus_list_lock);
227	kfree(zbus);
228}
229
230static void zpci_bus_put(struct zpci_bus *zbus)
231{
232	kref_put(&zbus->kref, zpci_bus_release);
233}
234
235static struct zpci_bus *zpci_bus_get(int pchid)
236{
237	struct zpci_bus *zbus;
238
239	mutex_lock(&zbus_list_lock);
240	list_for_each_entry(zbus, &zbus_list, bus_next) {
241		if (pchid == zbus->pchid) {
242			kref_get(&zbus->kref);
243			goto out_unlock;
244		}
245	}
246	zbus = NULL;
247out_unlock:
248	mutex_unlock(&zbus_list_lock);
249	return zbus;
250}
251
252static struct zpci_bus *zpci_bus_alloc(int pchid)
253{
254	struct zpci_bus *zbus;
255
256	zbus = kzalloc(sizeof(*zbus), GFP_KERNEL);
257	if (!zbus)
258		return NULL;
259
260	zbus->pchid = pchid;
261	INIT_LIST_HEAD(&zbus->bus_next);
262	mutex_lock(&zbus_list_lock);
263	list_add_tail(&zbus->bus_next, &zbus_list);
264	mutex_unlock(&zbus_list_lock);
265
266	kref_init(&zbus->kref);
267	INIT_LIST_HEAD(&zbus->resources);
268
269	zbus->bus_resource.start = 0;
270	zbus->bus_resource.end = ZPCI_BUS_NR;
271	zbus->bus_resource.flags = IORESOURCE_BUS;
272	pci_add_resource(&zbus->resources, &zbus->bus_resource);
273
274	return zbus;
275}
276
277void pcibios_bus_add_device(struct pci_dev *pdev)
278{
279	struct zpci_dev *zdev = to_zpci(pdev);
280
281	/*
282	 * With pdev->no_vf_scan the common PCI probing code does not
283	 * perform PF/VF linking.
284	 */
285	if (zdev->vfn) {
286		zpci_iov_setup_virtfn(zdev->zbus, pdev, zdev->vfn);
287		pdev->no_command_memory = 1;
288	}
289}
290
291static int zpci_bus_add_device(struct zpci_bus *zbus, struct zpci_dev *zdev)
292{
293	int rc = -EINVAL;
294
295	if (zbus->function[zdev->devfn]) {
296		pr_err("devfn %04x is already assigned\n", zdev->devfn);
297		return rc;
298	}
299
300	zdev->zbus = zbus;
301	zbus->function[zdev->devfn] = zdev;
302	zpci_nb_devices++;
303
304	if (zbus->multifunction && !zdev->rid_available) {
305		WARN_ONCE(1, "rid_available not set for multifunction\n");
306		goto error;
307	}
308	rc = zpci_init_slot(zdev);
309	if (rc)
310		goto error;
311	zdev->has_hp_slot = 1;
312
313	return 0;
314
315error:
316	zbus->function[zdev->devfn] = NULL;
317	zdev->zbus = NULL;
318	zpci_nb_devices--;
319	return rc;
320}
321
322int zpci_bus_device_register(struct zpci_dev *zdev, struct pci_ops *ops)
323{
324	struct zpci_bus *zbus = NULL;
325	int rc = -EBADF;
326
327	if (zpci_nb_devices == ZPCI_NR_DEVICES) {
328		pr_warn("Adding PCI function %08x failed because the configured limit of %d is reached\n",
329			zdev->fid, ZPCI_NR_DEVICES);
330		return -ENOSPC;
331	}
332
333	if (zdev->devfn >= ZPCI_FUNCTIONS_PER_BUS)
334		return -EINVAL;
335
336	if (!s390_pci_no_rid && zdev->rid_available)
337		zbus = zpci_bus_get(zdev->pchid);
338
339	if (!zbus) {
340		zbus = zpci_bus_alloc(zdev->pchid);
341		if (!zbus)
342			return -ENOMEM;
343	}
344
345	if (!zbus->bus) {
346		/* The UID of the first PCI function registered with a zpci_bus
347		 * is used as the domain number for that bus. Currently there
348		 * is exactly one zpci_bus per domain.
349		 */
350		rc = zpci_bus_create_pci_bus(zbus, zdev, ops);
351		if (rc)
352			goto error;
353	}
354
355	rc = zpci_bus_add_device(zbus, zdev);
356	if (rc)
357		goto error;
358
359	return 0;
360
361error:
362	pr_err("Adding PCI function %08x failed\n", zdev->fid);
363	zpci_bus_put(zbus);
364	return rc;
365}
366
367void zpci_bus_device_unregister(struct zpci_dev *zdev)
368{
369	struct zpci_bus *zbus = zdev->zbus;
370
371	zpci_nb_devices--;
372	zbus->function[zdev->devfn] = NULL;
373	zpci_bus_put(zbus);
374}
375