opal-psr.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * PowerNV OPAL Power-Shift-Ratio interface
  4 *
  5 * Copyright 2017 IBM Corp.
  6 */
  7
  8#define pr_fmt(fmt)     "opal-psr: " fmt
  9
 10#include <linux/of.h>
 11#include <linux/kobject.h>
 12#include <linux/slab.h>
 13
 14#include <asm/opal.h>
 15
 16static DEFINE_MUTEX(psr_mutex);
 17
 18static struct kobject *psr_kobj;
 19
 20static struct psr_attr {
 21	u32 handle;
 22	struct kobj_attribute attr;
 23} *psr_attrs;
 24
 25static ssize_t psr_show(struct kobject *kobj, struct kobj_attribute *attr,
 26			char *buf)
 27{
 28	struct psr_attr *psr_attr = container_of(attr, struct psr_attr, attr);
 29	struct opal_msg msg;
 30	int psr, ret, token;
 31
 32	token = opal_async_get_token_interruptible();
 33	if (token < 0) {
 34		pr_devel("Failed to get token\n");
 35		return token;
 36	}
 37
 38	ret = mutex_lock_interruptible(&psr_mutex);
 39	if (ret)
 40		goto out_token;
 41
 42	ret = opal_get_power_shift_ratio(psr_attr->handle, token,
 43					    (u32 *)__pa(&psr));
 44	switch (ret) {
 45	case OPAL_ASYNC_COMPLETION:
 46		ret = opal_async_wait_response(token, &msg);
 47		if (ret) {
 48			pr_devel("Failed to wait for the async response\n");
 49			ret = -EIO;
 50			goto out;
 51		}
 52		ret = opal_error_code(opal_get_async_rc(msg));
 53		if (!ret) {
 54			ret = sprintf(buf, "%u\n", be32_to_cpu(psr));
 55			if (ret < 0)
 56				ret = -EIO;
 57		}
 58		break;
 59	case OPAL_SUCCESS:
 60		ret = sprintf(buf, "%u\n", be32_to_cpu(psr));
 61		if (ret < 0)
 62			ret = -EIO;
 63		break;
 64	default:
 65		ret = opal_error_code(ret);
 66	}
 67
 68out:
 69	mutex_unlock(&psr_mutex);
 70out_token:
 71	opal_async_release_token(token);
 72	return ret;
 73}
 74
 75static ssize_t psr_store(struct kobject *kobj, struct kobj_attribute *attr,
 76			 const char *buf, size_t count)
 77{
 78	struct psr_attr *psr_attr = container_of(attr, struct psr_attr, attr);
 79	struct opal_msg msg;
 80	int psr, ret, token;
 81
 82	ret = kstrtoint(buf, 0, &psr);
 83	if (ret)
 84		return ret;
 85
 86	token = opal_async_get_token_interruptible();
 87	if (token < 0) {
 88		pr_devel("Failed to get token\n");
 89		return token;
 90	}
 91
 92	ret = mutex_lock_interruptible(&psr_mutex);
 93	if (ret)
 94		goto out_token;
 95
 96	ret = opal_set_power_shift_ratio(psr_attr->handle, token, psr);
 97	switch (ret) {
 98	case OPAL_ASYNC_COMPLETION:
 99		ret = opal_async_wait_response(token, &msg);
100		if (ret) {
101			pr_devel("Failed to wait for the async response\n");
102			ret = -EIO;
103			goto out;
104		}
105		ret = opal_error_code(opal_get_async_rc(msg));
106		if (!ret)
107			ret = count;
108		break;
109	case OPAL_SUCCESS:
110		ret = count;
111		break;
112	default:
113		ret = opal_error_code(ret);
114	}
115
116out:
117	mutex_unlock(&psr_mutex);
118out_token:
119	opal_async_release_token(token);
120	return ret;
121}
122
123void __init opal_psr_init(void)
124{
125	struct device_node *psr, *node;
126	int i = 0;
127
128	psr = of_find_compatible_node(NULL, NULL,
129				      "ibm,opal-power-shift-ratio");
130	if (!psr) {
131		pr_devel("Power-shift-ratio node not found\n");
132		return;
133	}
134
135	psr_attrs = kcalloc(of_get_child_count(psr), sizeof(*psr_attrs),
136			    GFP_KERNEL);
137	if (!psr_attrs)
138		goto out_put_psr;
139
140	psr_kobj = kobject_create_and_add("psr", opal_kobj);
141	if (!psr_kobj) {
142		pr_warn("Failed to create psr kobject\n");
143		goto out;
144	}
145
146	for_each_child_of_node(psr, node) {
147		if (of_property_read_u32(node, "handle",
148					 &psr_attrs[i].handle))
149			goto out_kobj;
150
151		sysfs_attr_init(&psr_attrs[i].attr.attr);
152		if (of_property_read_string(node, "label",
153					    &psr_attrs[i].attr.attr.name))
154			goto out_kobj;
155		psr_attrs[i].attr.attr.mode = 0664;
156		psr_attrs[i].attr.show = psr_show;
157		psr_attrs[i].attr.store = psr_store;
158		if (sysfs_create_file(psr_kobj, &psr_attrs[i].attr.attr)) {
159			pr_devel("Failed to create psr sysfs file %s\n",
160				 psr_attrs[i].attr.attr.name);
161			goto out_kobj;
162		}
163		i++;
164	}
165	of_node_put(psr);
166
167	return;
168out_kobj:
169	of_node_put(node);
170	kobject_put(psr_kobj);
171out:
172	kfree(psr_attrs);
173out_put_psr:
174	of_node_put(psr);
175}