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
 29const struct scom_controller *scom_controller;
 30EXPORT_SYMBOL_GPL(scom_controller);
 31
 32struct 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}
 50EXPORT_SYMBOL_GPL(scom_find_parent);
 51
 52scom_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}
 96EXPORT_SYMBOL_GPL(scom_map_device);
 97
 98#ifdef CONFIG_SCOM_DEBUGFS
 99struct scom_debug_entry {
100	struct device_node *dn;
101	struct debugfs_blob_wrapper path;
102	char name[16];
103};
104
105static 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
142static 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
178static 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
185static 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
214static 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}
235device_initcall(scom_debug_init);
236#endif /* CONFIG_SCOM_DEBUGFS */