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	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 */
 77int 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 */
107void 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 */
143int 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 */
170void 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 */
192static 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
221static 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
242static void zpci_bus_put(struct zpci_bus *zbus)
243{
244	kref_put(&zbus->kref, zpci_bus_release);
245}
246
247static 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;
259out_unlock:
260	mutex_unlock(&zbus_list_lock);
261	return zbus;
262}
263
264static 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
289void 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
303static 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
327error:
328	zbus->function[zdev->devfn] = NULL;
329	zdev->zbus = NULL;
330	zpci_nb_devices--;
331	return rc;
332}
333
334int 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
373error:
374	pr_err("Adding PCI function %08x failed\n", zdev->fid);
375	zpci_bus_put(zbus);
376	return rc;
377}
378
379void 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}