1 /*
2 * Copyright 2010 Benjamin Herrenschmidt, IBM Corp
3 * <benh@kernel.crashing.org>
4 * and David Gibson, IBM Corporation.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
14 * the GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19 */
20
21 #include <linux/kernel.h>
22 #include <linux/slab.h>
23 #include <linux/export.h>
24 #include <asm/debugfs.h>
25 #include <asm/prom.h>
26 #include <asm/scom.h>
27 #include <linux/uaccess.h>
28
29 const struct scom_controller *scom_controller;
30 EXPORT_SYMBOL_GPL(scom_controller);
31
scom_find_parent(struct device_node * node)32 struct device_node *scom_find_parent(struct device_node *node)
33 {
34 struct device_node *par, *tmp;
35 const u32 *p;
36
37 for (par = of_node_get(node); par;) {
38 if (of_get_property(par, "scom-controller", NULL))
39 break;
40 p = of_get_property(par, "scom-parent", NULL);
41 tmp = par;
42 if (p == NULL)
43 par = of_get_parent(par);
44 else
45 par = of_find_node_by_phandle(*p);
46 of_node_put(tmp);
47 }
48 return par;
49 }
50 EXPORT_SYMBOL_GPL(scom_find_parent);
51
scom_map_device(struct device_node * dev,int index)52 scom_map_t scom_map_device(struct device_node *dev, int index)
53 {
54 struct device_node *parent;
55 unsigned int cells, size;
56 const __be32 *prop, *sprop;
57 u64 reg, cnt;
58 scom_map_t ret;
59
60 parent = scom_find_parent(dev);
61
62 if (parent == NULL)
63 return 0;
64
65 /*
66 * We support "scom-reg" properties for adding scom registers
67 * to a random device-tree node with an explicit scom-parent
68 *
69 * We also support the simple "reg" property if the device is
70 * a direct child of a scom controller.
71 *
72 * In case both exist, "scom-reg" takes precedence.
73 */
74 prop = of_get_property(dev, "scom-reg", &size);
75 sprop = of_get_property(parent, "#scom-cells", NULL);
76 if (!prop && parent == dev->parent) {
77 prop = of_get_property(dev, "reg", &size);
78 sprop = of_get_property(parent, "#address-cells", NULL);
79 }
80 if (!prop)
81 return NULL;
82 cells = sprop ? be32_to_cpup(sprop) : 1;
83 size >>= 2;
84
85 if (index >= (size / (2*cells)))
86 return 0;
87
88 reg = of_read_number(&prop[index * cells * 2], cells);
89 cnt = of_read_number(&prop[index * cells * 2 + cells], cells);
90
91 ret = scom_map(parent, reg, cnt);
92 of_node_put(parent);
93
94 return ret;
95 }
96 EXPORT_SYMBOL_GPL(scom_map_device);
97
98 #ifdef CONFIG_SCOM_DEBUGFS
99 struct scom_debug_entry {
100 struct device_node *dn;
101 struct debugfs_blob_wrapper path;
102 char name[16];
103 };
104
scom_debug_read(struct file * filp,char __user * ubuf,size_t count,loff_t * ppos)105 static ssize_t scom_debug_read(struct file *filp, char __user *ubuf,
106 size_t count, loff_t *ppos)
107 {
108 struct scom_debug_entry *ent = filp->private_data;
109 u64 __user *ubuf64 = (u64 __user *)ubuf;
110 loff_t off = *ppos;
111 ssize_t done = 0;
112 u64 reg, reg_cnt, val;
113 scom_map_t map;
114 int rc;
115
116 if (off < 0 || (off & 7) || (count & 7))
117 return -EINVAL;
118 reg = off >> 3;
119 reg_cnt = count >> 3;
120
121 map = scom_map(ent->dn, reg, reg_cnt);
122 if (!scom_map_ok(map))
123 return -ENXIO;
124
125 for (reg = 0; reg < reg_cnt; reg++) {
126 rc = scom_read(map, reg, &val);
127 if (!rc)
128 rc = put_user(val, ubuf64);
129 if (rc) {
130 if (!done)
131 done = rc;
132 break;
133 }
134 ubuf64++;
135 *ppos += 8;
136 done += 8;
137 }
138 scom_unmap(map);
139 return done;
140 }
141
scom_debug_write(struct file * filp,const char __user * ubuf,size_t count,loff_t * ppos)142 static ssize_t scom_debug_write(struct file* filp, const char __user *ubuf,
143 size_t count, loff_t *ppos)
144 {
145 struct scom_debug_entry *ent = filp->private_data;
146 u64 __user *ubuf64 = (u64 __user *)ubuf;
147 loff_t off = *ppos;
148 ssize_t done = 0;
149 u64 reg, reg_cnt, val;
150 scom_map_t map;
151 int rc;
152
153 if (off < 0 || (off & 7) || (count & 7))
154 return -EINVAL;
155 reg = off >> 3;
156 reg_cnt = count >> 3;
157
158 map = scom_map(ent->dn, reg, reg_cnt);
159 if (!scom_map_ok(map))
160 return -ENXIO;
161
162 for (reg = 0; reg < reg_cnt; reg++) {
163 rc = get_user(val, ubuf64);
164 if (!rc)
165 rc = scom_write(map, reg, val);
166 if (rc) {
167 if (!done)
168 done = rc;
169 break;
170 }
171 ubuf64++;
172 done += 8;
173 }
174 scom_unmap(map);
175 return done;
176 }
177
178 static const struct file_operations scom_debug_fops = {
179 .read = scom_debug_read,
180 .write = scom_debug_write,
181 .open = simple_open,
182 .llseek = default_llseek,
183 };
184
scom_debug_init_one(struct dentry * root,struct device_node * dn,int i)185 static int scom_debug_init_one(struct dentry *root, struct device_node *dn,
186 int i)
187 {
188 struct scom_debug_entry *ent;
189 struct dentry *dir;
190
191 ent = kzalloc(sizeof(*ent), GFP_KERNEL);
192 if (!ent)
193 return -ENOMEM;
194
195 ent->dn = of_node_get(dn);
196 snprintf(ent->name, 16, "%08x", i);
197 ent->path.data = (void*)kasprintf(GFP_KERNEL, "%pOF", dn);
198 ent->path.size = strlen((char *)ent->path.data);
199
200 dir = debugfs_create_dir(ent->name, root);
201 if (!dir) {
202 of_node_put(dn);
203 kfree(ent->path.data);
204 kfree(ent);
205 return -1;
206 }
207
208 debugfs_create_blob("devspec", 0400, dir, &ent->path);
209 debugfs_create_file("access", 0600, dir, ent, &scom_debug_fops);
210
211 return 0;
212 }
213
scom_debug_init(void)214 static int scom_debug_init(void)
215 {
216 struct device_node *dn;
217 struct dentry *root;
218 int i, rc;
219
220 root = debugfs_create_dir("scom", powerpc_debugfs_root);
221 if (!root)
222 return -1;
223
224 i = rc = 0;
225 for_each_node_with_property(dn, "scom-controller") {
226 int id = of_get_ibm_chip_id(dn);
227 if (id == -1)
228 id = i;
229 rc |= scom_debug_init_one(root, dn, id);
230 i++;
231 }
232
233 return rc;
234 }
235 device_initcall(scom_debug_init);
236 #endif /* CONFIG_SCOM_DEBUGFS */
237
