1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright 2022-23 IBM Corp.
4 */
5
6#define pr_fmt(fmt) "vas: " fmt
7
8#include <linux/module.h>
9#include <linux/kernel.h>
10#include <linux/miscdevice.h>
11#include <linux/kobject.h>
12#include <linux/slab.h>
13#include <linux/mm.h>
14
15#include "vas.h"
16
17#ifdef CONFIG_SYSFS
18static struct kobject *pseries_vas_kobj;
19static struct kobject *gzip_caps_kobj;
20
21struct vas_caps_entry {
22	struct kobject kobj;
23	struct vas_cop_feat_caps *caps;
24};
25
26#define to_caps_entry(entry) container_of(entry, struct vas_caps_entry, kobj)
27
28/*
29 * This function is used to get the notification from the drmgr when
30 * QoS credits are changed.
31 */
32static ssize_t update_total_credits_store(struct vas_cop_feat_caps *caps,
33						const char *buf, size_t count)
34{
35	int err;
36	u16 creds;
37
38	err = kstrtou16(buf, 0, &creds);
39	/*
40	 * The user space interface from the management console
41	 * notifies OS with the new QoS credits and then the
42	 * hypervisor. So OS has to use this new credits value
43	 * and reconfigure VAS windows (close or reopen depends
44	 * on the credits available) instead of depending on VAS
45	 * QoS capabilities from the hypervisor.
46	 */
47	if (!err)
48		err = vas_reconfig_capabilties(caps->win_type, creds);
49
50	if (err)
51		return -EINVAL;
52
53	pr_info("Set QoS total credits %u\n", creds);
54
55	return count;
56}
57
58#define sysfs_caps_entry_read(_name)					\
59static ssize_t _name##_show(struct vas_cop_feat_caps *caps, char *buf) 	\
60{									\
61	return sprintf(buf, "%d\n", atomic_read(&caps->_name));	\
62}
63
64struct vas_sysfs_entry {
65	struct attribute attr;
66	ssize_t (*show)(struct vas_cop_feat_caps *, char *);
67	ssize_t (*store)(struct vas_cop_feat_caps *, const char *, size_t);
68};
69
70#define VAS_ATTR_RO(_name)	\
71	sysfs_caps_entry_read(_name);		\
72	static struct vas_sysfs_entry _name##_attribute = __ATTR(_name,	\
73				0444, _name##_show, NULL);
74
75/*
76 * Create sysfs interface:
77 * /sys/devices/virtual/misc/vas/vas0/gzip/default_capabilities
78 *	This directory contains the following VAS GZIP capabilities
79 *	for the default credit type.
80 * /sys/devices/virtual/misc/vas/vas0/gzip/default_capabilities/nr_total_credits
81 *	Total number of default credits assigned to the LPAR which
82 *	can be changed with DLPAR operation.
83 * /sys/devices/virtual/misc/vas/vas0/gzip/default_capabilities/nr_used_credits
84 *	Number of credits used by the user space. One credit will
85 *	be assigned for each window open.
86 *
87 * /sys/devices/virtual/misc/vas/vas0/gzip/qos_capabilities
88 *	This directory contains the following VAS GZIP capabilities
89 *	for the Quality of Service (QoS) credit type.
90 * /sys/devices/virtual/misc/vas/vas0/gzip/qos_capabilities/nr_total_credits
91 *	Total number of QoS credits assigned to the LPAR. The user
92 *	has to define this value using HMC interface. It can be
93 *	changed dynamically by the user.
94 * /sys/devices/virtual/misc/vas/vas0/gzip/qos_capabilities/nr_used_credits
95 *	Number of credits used by the user space.
96 * /sys/devices/virtual/misc/vas/vas0/gzip/qos_capabilities/update_total_credits
97 *	Update total QoS credits dynamically
98 */
99
100VAS_ATTR_RO(nr_total_credits);
101VAS_ATTR_RO(nr_used_credits);
102
103static struct vas_sysfs_entry update_total_credits_attribute =
104	__ATTR(update_total_credits, 0200, NULL, update_total_credits_store);
105
106static struct attribute *vas_def_capab_attrs[] = {
107	&nr_total_credits_attribute.attr,
108	&nr_used_credits_attribute.attr,
109	NULL,
110};
111ATTRIBUTE_GROUPS(vas_def_capab);
112
113static struct attribute *vas_qos_capab_attrs[] = {
114	&nr_total_credits_attribute.attr,
115	&nr_used_credits_attribute.attr,
116	&update_total_credits_attribute.attr,
117	NULL,
118};
119ATTRIBUTE_GROUPS(vas_qos_capab);
120
121static ssize_t vas_type_show(struct kobject *kobj, struct attribute *attr,
122			     char *buf)
123{
124	struct vas_caps_entry *centry;
125	struct vas_cop_feat_caps *caps;
126	struct vas_sysfs_entry *entry;
127
128	centry = to_caps_entry(kobj);
129	caps = centry->caps;
130	entry = container_of(attr, struct vas_sysfs_entry, attr);
131
132	if (!entry->show)
133		return -EIO;
134
135	return entry->show(caps, buf);
136}
137
138static ssize_t vas_type_store(struct kobject *kobj, struct attribute *attr,
139			      const char *buf, size_t count)
140{
141	struct vas_caps_entry *centry;
142	struct vas_cop_feat_caps *caps;
143	struct vas_sysfs_entry *entry;
144
145	centry = to_caps_entry(kobj);
146	caps = centry->caps;
147	entry = container_of(attr, struct vas_sysfs_entry, attr);
148	if (!entry->store)
149		return -EIO;
150
151	return entry->store(caps, buf, count);
152}
153
154static void vas_type_release(struct kobject *kobj)
155{
156	struct vas_caps_entry *centry = to_caps_entry(kobj);
157	kfree(centry);
158}
159
160static const struct sysfs_ops vas_sysfs_ops = {
161	.show	=	vas_type_show,
162	.store	=	vas_type_store,
163};
164
165static struct kobj_type vas_def_attr_type = {
166		.release	=	vas_type_release,
167		.sysfs_ops      =       &vas_sysfs_ops,
168		.default_groups	=	vas_def_capab_groups,
169};
170
171static struct kobj_type vas_qos_attr_type = {
172		.release	=	vas_type_release,
173		.sysfs_ops	=	&vas_sysfs_ops,
174		.default_groups	=	vas_qos_capab_groups,
175};
176
177static char *vas_caps_kobj_name(struct vas_caps_entry *centry,
178				struct kobject **kobj)
179{
180	struct vas_cop_feat_caps *caps = centry->caps;
181
182	if (caps->descriptor == VAS_GZIP_QOS_CAPABILITIES) {
183		kobject_init(&centry->kobj, &vas_qos_attr_type);
184		*kobj = gzip_caps_kobj;
185		return "qos_capabilities";
186	} else if (caps->descriptor == VAS_GZIP_DEFAULT_CAPABILITIES) {
187		kobject_init(&centry->kobj, &vas_def_attr_type);
188		*kobj = gzip_caps_kobj;
189		return "default_capabilities";
190	} else
191		return "Unknown";
192}
193
194/*
195 * Add feature specific capability dir entry.
196 * Ex: VDefGzip or VQosGzip
197 */
198int sysfs_add_vas_caps(struct vas_cop_feat_caps *caps)
199{
200	struct vas_caps_entry *centry;
201	struct kobject *kobj = NULL;
202	int ret = 0;
203	char *name;
204
205	centry = kzalloc(sizeof(*centry), GFP_KERNEL);
206	if (!centry)
207		return -ENOMEM;
208
209	centry->caps = caps;
210	name  = vas_caps_kobj_name(centry, &kobj);
211
212	if (kobj) {
213		ret = kobject_add(&centry->kobj, kobj, "%s", name);
214
215		if (ret) {
216			pr_err("VAS: sysfs kobject add / event failed %d\n",
217					ret);
218			kobject_put(&centry->kobj);
219		}
220	}
221
222	return ret;
223}
224
225static struct miscdevice vas_miscdev = {
226	.minor = MISC_DYNAMIC_MINOR,
227	.name = "vas",
228};
229
230/*
231 * Add VAS and VasCaps (overall capabilities) dir entries.
232 */
233int __init sysfs_pseries_vas_init(struct vas_all_caps *vas_caps)
234{
235	int ret;
236
237	ret = misc_register(&vas_miscdev);
238	if (ret < 0) {
239		pr_err("%s: register vas misc device failed\n", __func__);
240		return ret;
241	}
242
243	/*
244	 * The hypervisor does not expose multiple VAS instances, but can
245	 * see multiple VAS instances on PowerNV. So create 'vas0' directory
246	 * on pseries.
247	 */
248	pseries_vas_kobj = kobject_create_and_add("vas0",
249					&vas_miscdev.this_device->kobj);
250	if (!pseries_vas_kobj) {
251		misc_deregister(&vas_miscdev);
252		pr_err("Failed to create VAS sysfs entry\n");
253		return -ENOMEM;
254	}
255
256	if ((vas_caps->feat_type & VAS_GZIP_QOS_FEAT_BIT) ||
257		(vas_caps->feat_type & VAS_GZIP_DEF_FEAT_BIT)) {
258		gzip_caps_kobj = kobject_create_and_add("gzip",
259						       pseries_vas_kobj);
260		if (!gzip_caps_kobj) {
261			pr_err("Failed to create VAS GZIP capability entry\n");
262			kobject_put(pseries_vas_kobj);
263			misc_deregister(&vas_miscdev);
264			return -ENOMEM;
265		}
266	}
267
268	return 0;
269}
270
271#else
272int sysfs_add_vas_caps(struct vas_cop_feat_caps *caps)
273{
274	return 0;
275}
276
277int __init sysfs_pseries_vas_init(struct vas_all_caps *vas_caps)
278{
279	return 0;
280}
281#endif
282