1 /*
2  * Windfarm PowerMac thermal control.  SMU "satellite" controller sensors.
3  *
4  * Copyright (C) 2005 Paul Mackerras, IBM Corp. <paulus@samba.org>
5  *
6  * Released under the terms of the GNU GPL v2.
7  */
8 
9 #include <linux/types.h>
10 #include <linux/errno.h>
11 #include <linux/kernel.h>
12 #include <linux/slab.h>
13 #include <linux/init.h>
14 #include <linux/wait.h>
15 #include <linux/i2c.h>
16 #include <linux/mutex.h>
17 #include <asm/prom.h>
18 #include <asm/smu.h>
19 #include <asm/pmac_low_i2c.h>
20 
21 #include "windfarm.h"
22 
23 #define VERSION "1.0"
24 
25 /* If the cache is older than 800ms we'll refetch it */
26 #define MAX_AGE		msecs_to_jiffies(800)
27 
28 struct wf_sat {
29 	struct kref		ref;
30 	int			nr;
31 	struct mutex		mutex;
32 	unsigned long		last_read; /* jiffies when cache last updated */
33 	u8			cache[16];
34 	struct list_head	sensors;
35 	struct i2c_client	*i2c;
36 	struct device_node	*node;
37 };
38 
39 static struct wf_sat *sats[2];
40 
41 struct wf_sat_sensor {
42 	struct list_head	link;
43 	int			index;
44 	int			index2;		/* used for power sensors */
45 	int			shift;
46 	struct wf_sat		*sat;
47 	struct wf_sensor 	sens;
48 };
49 
50 #define wf_to_sat(c)	container_of(c, struct wf_sat_sensor, sens)
51 
52 struct smu_sdbp_header *smu_sat_get_sdb_partition(unsigned int sat_id, int id,
53 						  unsigned int *size)
54 {
55 	struct wf_sat *sat;
56 	int err;
57 	unsigned int i, len;
58 	u8 *buf;
59 	u8 data[4];
60 
61 	/* TODO: Add the resulting partition to the device-tree */
62 
63 	if (sat_id > 1 || (sat = sats[sat_id]) == NULL)
64 		return NULL;
65 
66 	err = i2c_smbus_write_word_data(sat->i2c, 8, id << 8);
67 	if (err) {
68 		printk(KERN_ERR "smu_sat_get_sdb_part wr error %d\n", err);
69 		return NULL;
70 	}
71 
72 	err = i2c_smbus_read_word_data(sat->i2c, 9);
73 	if (err < 0) {
74 		printk(KERN_ERR "smu_sat_get_sdb_part rd len error\n");
75 		return NULL;
76 	}
77 	len = err;
78 	if (len == 0) {
79 		printk(KERN_ERR "smu_sat_get_sdb_part no partition %x\n", id);
80 		return NULL;
81 	}
82 
83 	len = le16_to_cpu(len);
84 	len = (len + 3) & ~3;
85 	buf = kmalloc(len, GFP_KERNEL);
86 	if (buf == NULL)
87 		return NULL;
88 
89 	for (i = 0; i < len; i += 4) {
90 		err = i2c_smbus_read_i2c_block_data(sat->i2c, 0xa, 4, data);
91 		if (err < 0) {
92 			printk(KERN_ERR "smu_sat_get_sdb_part rd err %d\n",
93 			       err);
94 			goto fail;
95 		}
96 		buf[i] = data[1];
97 		buf[i+1] = data[0];
98 		buf[i+2] = data[3];
99 		buf[i+3] = data[2];
100 	}
101 
102 	printk(KERN_DEBUG "sat %d partition %x:", sat_id, id);
103 	print_hex_dump(KERN_DEBUG, "  ", DUMP_PREFIX_OFFSET,
104 		       16, 1, buf, len, false);
105 	if (size)
106 		*size = len;
107 	return (struct smu_sdbp_header *) buf;
108 
109  fail:
110 	kfree(buf);
111 	return NULL;
112 }
113 EXPORT_SYMBOL_GPL(smu_sat_get_sdb_partition);
114 
115 /* refresh the cache */
116 static int wf_sat_read_cache(struct wf_sat *sat)
117 {
118 	int err;
119 
120 	err = i2c_smbus_read_i2c_block_data(sat->i2c, 0x3f, 16, sat->cache);
121 	if (err < 0)
122 		return err;
123 	sat->last_read = jiffies;
124 
125 #ifdef LOTSA_DEBUG
126 	{
127 		int i;
128 		printk(KERN_DEBUG "wf_sat_get: data is");
129 		print_hex_dump(KERN_DEBUG, "  ", DUMP_PREFIX_OFFSET,
130 			       16, 1, sat->cache, 16, false);
131 	}
132 #endif
133 	return 0;
134 }
135 
136 static int wf_sat_sensor_get(struct wf_sensor *sr, s32 *value)
137 {
138 	struct wf_sat_sensor *sens = wf_to_sat(sr);
139 	struct wf_sat *sat = sens->sat;
140 	int i, err;
141 	s32 val;
142 
143 	if (sat->i2c == NULL)
144 		return -ENODEV;
145 
146 	mutex_lock(&sat->mutex);
147 	if (time_after(jiffies, (sat->last_read + MAX_AGE))) {
148 		err = wf_sat_read_cache(sat);
149 		if (err)
150 			goto fail;
151 	}
152 
153 	i = sens->index * 2;
154 	val = ((sat->cache[i] << 8) + sat->cache[i+1]) << sens->shift;
155 	if (sens->index2 >= 0) {
156 		i = sens->index2 * 2;
157 		/* 4.12 * 8.8 -> 12.20; shift right 4 to get 16.16 */
158 		val = (val * ((sat->cache[i] << 8) + sat->cache[i+1])) >> 4;
159 	}
160 
161 	*value = val;
162 	err = 0;
163 
164  fail:
165 	mutex_unlock(&sat->mutex);
166 	return err;
167 }
168 
169 static void wf_sat_release(struct kref *ref)
170 {
171 	struct wf_sat *sat = container_of(ref, struct wf_sat, ref);
172 
173 	if (sat->nr >= 0)
174 		sats[sat->nr] = NULL;
175 	kfree(sat);
176 }
177 
178 static void wf_sat_sensor_release(struct wf_sensor *sr)
179 {
180 	struct wf_sat_sensor *sens = wf_to_sat(sr);
181 	struct wf_sat *sat = sens->sat;
182 
183 	kfree(sens);
184 	kref_put(&sat->ref, wf_sat_release);
185 }
186 
187 static const struct wf_sensor_ops wf_sat_ops = {
188 	.get_value	= wf_sat_sensor_get,
189 	.release	= wf_sat_sensor_release,
190 	.owner		= THIS_MODULE,
191 };
192 
193 static int wf_sat_probe(struct i2c_client *client,
194 			const struct i2c_device_id *id)
195 {
196 	struct device_node *dev = client->dev.of_node;
197 	struct wf_sat *sat;
198 	struct wf_sat_sensor *sens;
199 	const u32 *reg;
200 	const char *loc;
201 	u8 chip, core;
202 	struct device_node *child;
203 	int shift, cpu, index;
204 	char *name;
205 	int vsens[2], isens[2];
206 
207 	sat = kzalloc(sizeof(struct wf_sat), GFP_KERNEL);
208 	if (sat == NULL)
209 		return -ENOMEM;
210 	sat->nr = -1;
211 	sat->node = of_node_get(dev);
212 	kref_init(&sat->ref);
213 	mutex_init(&sat->mutex);
214 	sat->i2c = client;
215 	INIT_LIST_HEAD(&sat->sensors);
216 	i2c_set_clientdata(client, sat);
217 
218 	vsens[0] = vsens[1] = -1;
219 	isens[0] = isens[1] = -1;
220 	child = NULL;
221 	while ((child = of_get_next_child(dev, child)) != NULL) {
222 		reg = of_get_property(child, "reg", NULL);
223 		loc = of_get_property(child, "location", NULL);
224 		if (reg == NULL || loc == NULL)
225 			continue;
226 
227 		/* the cooked sensors are between 0x30 and 0x37 */
228 		if (*reg < 0x30 || *reg > 0x37)
229 			continue;
230 		index = *reg - 0x30;
231 
232 		/* expect location to be CPU [AB][01] ... */
233 		if (strncmp(loc, "CPU ", 4) != 0)
234 			continue;
235 		chip = loc[4] - 'A';
236 		core = loc[5] - '0';
237 		if (chip > 1 || core > 1) {
238 			printk(KERN_ERR "wf_sat_create: don't understand "
239 			       "location %s for %pOF\n", loc, child);
240 			continue;
241 		}
242 		cpu = 2 * chip + core;
243 		if (sat->nr < 0)
244 			sat->nr = chip;
245 		else if (sat->nr != chip) {
246 			printk(KERN_ERR "wf_sat_create: can't cope with "
247 			       "multiple CPU chips on one SAT (%s)\n", loc);
248 			continue;
249 		}
250 
251 		if (of_node_is_type(child, "voltage-sensor")) {
252 			name = "cpu-voltage";
253 			shift = 4;
254 			vsens[core] = index;
255 		} else if (of_node_is_type(child, "current-sensor")) {
256 			name = "cpu-current";
257 			shift = 8;
258 			isens[core] = index;
259 		} else if (of_node_is_type(child, "temp-sensor")) {
260 			name = "cpu-temp";
261 			shift = 10;
262 		} else
263 			continue;	/* hmmm shouldn't happen */
264 
265 		/* the +16 is enough for "cpu-voltage-n" */
266 		sens = kzalloc(sizeof(struct wf_sat_sensor) + 16, GFP_KERNEL);
267 		if (sens == NULL) {
268 			printk(KERN_ERR "wf_sat_create: couldn't create "
269 			       "%s sensor %d (no memory)\n", name, cpu);
270 			continue;
271 		}
272 		sens->index = index;
273 		sens->index2 = -1;
274 		sens->shift = shift;
275 		sens->sat = sat;
276 		sens->sens.ops = &wf_sat_ops;
277 		sens->sens.name = (char *) (sens + 1);
278 		snprintf((char *)sens->sens.name, 16, "%s-%d", name, cpu);
279 
280 		if (wf_register_sensor(&sens->sens))
281 			kfree(sens);
282 		else {
283 			list_add(&sens->link, &sat->sensors);
284 			kref_get(&sat->ref);
285 		}
286 	}
287 
288 	/* make the power sensors */
289 	for (core = 0; core < 2; ++core) {
290 		if (vsens[core] < 0 || isens[core] < 0)
291 			continue;
292 		cpu = 2 * sat->nr + core;
293 		sens = kzalloc(sizeof(struct wf_sat_sensor) + 16, GFP_KERNEL);
294 		if (sens == NULL) {
295 			printk(KERN_ERR "wf_sat_create: couldn't create power "
296 			       "sensor %d (no memory)\n", cpu);
297 			continue;
298 		}
299 		sens->index = vsens[core];
300 		sens->index2 = isens[core];
301 		sens->shift = 0;
302 		sens->sat = sat;
303 		sens->sens.ops = &wf_sat_ops;
304 		sens->sens.name = (char *) (sens + 1);
305 		snprintf((char *)sens->sens.name, 16, "cpu-power-%d", cpu);
306 
307 		if (wf_register_sensor(&sens->sens))
308 			kfree(sens);
309 		else {
310 			list_add(&sens->link, &sat->sensors);
311 			kref_get(&sat->ref);
312 		}
313 	}
314 
315 	if (sat->nr >= 0)
316 		sats[sat->nr] = sat;
317 
318 	return 0;
319 }
320 
321 static int wf_sat_remove(struct i2c_client *client)
322 {
323 	struct wf_sat *sat = i2c_get_clientdata(client);
324 	struct wf_sat_sensor *sens;
325 
326 	/* release sensors */
327 	while(!list_empty(&sat->sensors)) {
328 		sens = list_first_entry(&sat->sensors,
329 					struct wf_sat_sensor, link);
330 		list_del(&sens->link);
331 		wf_unregister_sensor(&sens->sens);
332 	}
333 	sat->i2c = NULL;
334 	kref_put(&sat->ref, wf_sat_release);
335 
336 	return 0;
337 }
338 
339 static const struct i2c_device_id wf_sat_id[] = {
340 	{ "MAC,smu-sat", 0 },
341 	{ }
342 };
343 MODULE_DEVICE_TABLE(i2c, wf_sat_id);
344 
345 static struct i2c_driver wf_sat_driver = {
346 	.driver = {
347 		.name		= "wf_smu_sat",
348 	},
349 	.probe		= wf_sat_probe,
350 	.remove		= wf_sat_remove,
351 	.id_table	= wf_sat_id,
352 };
353 
354 module_i2c_driver(wf_sat_driver);
355 
356 MODULE_AUTHOR("Paul Mackerras <paulus@samba.org>");
357 MODULE_DESCRIPTION("SMU satellite sensors for PowerMac thermal control");
358 MODULE_LICENSE("GPL");
359