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/debugfs.h>
23 #include <linux/slab.h>
24 #include <linux/export.h>
25 #include <asm/debug.h>
26 #include <asm/prom.h>
27 #include <asm/scom.h>
28 #include <asm/uaccess.h>
29
30 const struct scom_controller *scom_controller;
31 EXPORT_SYMBOL_GPL(scom_controller);
32
scom_find_parent(struct device_node * node)33 struct device_node *scom_find_parent(struct device_node *node)
34 {
35 struct device_node *par, *tmp;
36 const u32 *p;
37
38 for (par = of_node_get(node); par;) {
39 if (of_get_property(par, "scom-controller", NULL))
40 break;
41 p = of_get_property(par, "scom-parent", NULL);
42 tmp = par;
43 if (p == NULL)
44 par = of_get_parent(par);
45 else
46 par = of_find_node_by_phandle(*p);
47 of_node_put(tmp);
48 }
49 return par;
50 }
51 EXPORT_SYMBOL_GPL(scom_find_parent);
52
scom_map_device(struct device_node * dev,int index)53 scom_map_t scom_map_device(struct device_node *dev, int index)
54 {
55 struct device_node *parent;
56 unsigned int cells, size;
57 const __be32 *prop, *sprop;
58 u64 reg, cnt;
59 scom_map_t ret;
60
61 parent = scom_find_parent(dev);
62
63 if (parent == NULL)
64 return 0;
65
66 /*
67 * We support "scom-reg" properties for adding scom registers
68 * to a random device-tree node with an explicit scom-parent
69 *
70 * We also support the simple "reg" property if the device is
71 * a direct child of a scom controller.
72 *
73 * In case both exist, "scom-reg" takes precedence.
74 */
75 prop = of_get_property(dev, "scom-reg", &size);
76 sprop = of_get_property(parent, "#scom-cells", NULL);
77 if (!prop && parent == dev->parent) {
78 prop = of_get_property(dev, "reg", &size);
79 sprop = of_get_property(parent, "#address-cells", NULL);
80 }
81 if (!prop)
82 return NULL;
83 cells = sprop ? be32_to_cpup(sprop) : 1;
84 size >>= 2;
85
86 if (index >= (size / (2*cells)))
87 return 0;
88
89 reg = of_read_number(&prop[index * cells * 2], cells);
90 cnt = of_read_number(&prop[index * cells * 2 + cells], cells);
91
92 ret = scom_map(parent, reg, cnt);
93 of_node_put(parent);
94
95 return ret;
96 }
97 EXPORT_SYMBOL_GPL(scom_map_device);
98
99 #ifdef CONFIG_SCOM_DEBUGFS
100 struct scom_debug_entry {
101 struct device_node *dn;
102 struct debugfs_blob_wrapper path;
103 char name[16];
104 };
105
scom_debug_read(struct file * filp,char __user * ubuf,size_t count,loff_t * ppos)106 static ssize_t scom_debug_read(struct file *filp, char __user *ubuf,
107 size_t count, loff_t *ppos)
108 {
109 struct scom_debug_entry *ent = filp->private_data;
110 u64 __user *ubuf64 = (u64 __user *)ubuf;
111 loff_t off = *ppos;
112 ssize_t done = 0;
113 u64 reg, reg_cnt, val;
114 scom_map_t map;
115 int rc;
116
117 if (off < 0 || (off & 7) || (count & 7))
118 return -EINVAL;
119 reg = off >> 3;
120 reg_cnt = count >> 3;
121
122 map = scom_map(ent->dn, reg, reg_cnt);
123 if (!scom_map_ok(map))
124 return -ENXIO;
125
126 for (reg = 0; reg < reg_cnt; reg++) {
127 rc = scom_read(map, reg, &val);
128 if (!rc)
129 rc = put_user(val, ubuf64);
130 if (rc) {
131 if (!done)
132 done = rc;
133 break;
134 }
135 ubuf64++;
136 *ppos += 8;
137 done += 8;
138 }
139 scom_unmap(map);
140 return done;
141 }
142
scom_debug_write(struct file * filp,const char __user * ubuf,size_t count,loff_t * ppos)143 static ssize_t scom_debug_write(struct file* filp, const char __user *ubuf,
144 size_t count, loff_t *ppos)
145 {
146 struct scom_debug_entry *ent = filp->private_data;
147 u64 __user *ubuf64 = (u64 __user *)ubuf;
148 loff_t off = *ppos;
149 ssize_t done = 0;
150 u64 reg, reg_cnt, val;
151 scom_map_t map;
152 int rc;
153
154 if (off < 0 || (off & 7) || (count & 7))
155 return -EINVAL;
156 reg = off >> 3;
157 reg_cnt = count >> 3;
158
159 map = scom_map(ent->dn, reg, reg_cnt);
160 if (!scom_map_ok(map))
161 return -ENXIO;
162
163 for (reg = 0; reg < reg_cnt; reg++) {
164 rc = get_user(val, ubuf64);
165 if (!rc)
166 rc = scom_write(map, reg, val);
167 if (rc) {
168 if (!done)
169 done = rc;
170 break;
171 }
172 ubuf64++;
173 done += 8;
174 }
175 scom_unmap(map);
176 return done;
177 }
178
179 static const struct file_operations scom_debug_fops = {
180 .read = scom_debug_read,
181 .write = scom_debug_write,
182 .open = simple_open,
183 .llseek = default_llseek,
184 };
185
scom_debug_init_one(struct dentry * root,struct device_node * dn,int i)186 static int scom_debug_init_one(struct dentry *root, struct device_node *dn,
187 int i)
188 {
189 struct scom_debug_entry *ent;
190 struct dentry *dir;
191
192 ent = kzalloc(sizeof(*ent), GFP_KERNEL);
193 if (!ent)
194 return -ENOMEM;
195
196 ent->dn = of_node_get(dn);
197 snprintf(ent->name, 16, "%08x", i);
198 ent->path.data = (void*) dn->full_name;
199 ent->path.size = strlen(dn->full_name);
200
201 dir = debugfs_create_dir(ent->name, root);
202 if (!dir) {
203 of_node_put(dn);
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