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 #define DEBUG
26 
27 #ifdef DEBUG
28 #define DBG(args...)	printk(args)
29 #else
30 #define DBG(args...)	do { } while(0)
31 #endif
32 
33 /* If the cache is older than 800ms we'll refetch it */
34 #define MAX_AGE		msecs_to_jiffies(800)
35 
36 struct wf_sat {
37 	struct kref		ref;
38 	int			nr;
39 	struct mutex		mutex;
40 	unsigned long		last_read; /* jiffies when cache last updated */
41 	u8			cache[16];
42 	struct list_head	sensors;
43 	struct i2c_client	*i2c;
44 	struct device_node	*node;
45 };
46 
47 static struct wf_sat *sats[2];
48 
49 struct wf_sat_sensor {
50 	struct list_head	link;
51 	int			index;
52 	int			index2;		/* used for power sensors */
53 	int			shift;
54 	struct wf_sat		*sat;
55 	struct wf_sensor 	sens;
56 };
57 
58 #define wf_to_sat(c)	container_of(c, struct wf_sat_sensor, sens)
59 
60 struct smu_sdbp_header *smu_sat_get_sdb_partition(unsigned int sat_id, int id,
61 						  unsigned int *size)
62 {
63 	struct wf_sat *sat;
64 	int err;
65 	unsigned int i, len;
66 	u8 *buf;
67 	u8 data[4];
68 
69 	/* TODO: Add the resulting partition to the device-tree */
70 
71 	if (sat_id > 1 || (sat = sats[sat_id]) == NULL)
72 		return NULL;
73 
74 	err = i2c_smbus_write_word_data(sat->i2c, 8, id << 8);
75 	if (err) {
76 		printk(KERN_ERR "smu_sat_get_sdb_part wr error %d\n", err);
77 		return NULL;
78 	}
79 
80 	err = i2c_smbus_read_word_data(sat->i2c, 9);
81 	if (err < 0) {
82 		printk(KERN_ERR "smu_sat_get_sdb_part rd len error\n");
83 		return NULL;
84 	}
85 	len = err;
86 	if (len == 0) {
87 		printk(KERN_ERR "smu_sat_get_sdb_part no partition %x\n", id);
88 		return NULL;
89 	}
90 
91 	len = le16_to_cpu(len);
92 	len = (len + 3) & ~3;
93 	buf = kmalloc(len, GFP_KERNEL);
94 	if (buf == NULL)
95 		return NULL;
96 
97 	for (i = 0; i < len; i += 4) {
98 		err = i2c_smbus_read_i2c_block_data(sat->i2c, 0xa, 4, data);
99 		if (err < 0) {
100 			printk(KERN_ERR "smu_sat_get_sdb_part rd err %d\n",
101 			       err);
102 			goto fail;
103 		}
104 		buf[i] = data[1];
105 		buf[i+1] = data[0];
106 		buf[i+2] = data[3];
107 		buf[i+3] = data[2];
108 	}
109 #ifdef DEBUG
110 	DBG(KERN_DEBUG "sat %d partition %x:", sat_id, id);
111 	for (i = 0; i < len; ++i)
112 		DBG(" %x", buf[i]);
113 	DBG("\n");
114 #endif
115 
116 	if (size)
117 		*size = len;
118 	return (struct smu_sdbp_header *) buf;
119 
120  fail:
121 	kfree(buf);
122 	return NULL;
123 }
124 EXPORT_SYMBOL_GPL(smu_sat_get_sdb_partition);
125 
126 /* refresh the cache */
127 static int wf_sat_read_cache(struct wf_sat *sat)
128 {
129 	int err;
130 
131 	err = i2c_smbus_read_i2c_block_data(sat->i2c, 0x3f, 16, sat->cache);
132 	if (err < 0)
133 		return err;
134 	sat->last_read = jiffies;
135 #ifdef LOTSA_DEBUG
136 	{
137 		int i;
138 		DBG(KERN_DEBUG "wf_sat_get: data is");
139 		for (i = 0; i < 16; ++i)
140 			DBG(" %.2x", sat->cache[i]);
141 		DBG("\n");
142 	}
143 #endif
144 	return 0;
145 }
146 
147 static int wf_sat_sensor_get(struct wf_sensor *sr, s32 *value)
148 {
149 	struct wf_sat_sensor *sens = wf_to_sat(sr);
150 	struct wf_sat *sat = sens->sat;
151 	int i, err;
152 	s32 val;
153 
154 	if (sat->i2c == NULL)
155 		return -ENODEV;
156 
157 	mutex_lock(&sat->mutex);
158 	if (time_after(jiffies, (sat->last_read + MAX_AGE))) {
159 		err = wf_sat_read_cache(sat);
160 		if (err)
161 			goto fail;
162 	}
163 
164 	i = sens->index * 2;
165 	val = ((sat->cache[i] << 8) + sat->cache[i+1]) << sens->shift;
166 	if (sens->index2 >= 0) {
167 		i = sens->index2 * 2;
168 		/* 4.12 * 8.8 -> 12.20; shift right 4 to get 16.16 */
169 		val = (val * ((sat->cache[i] << 8) + sat->cache[i+1])) >> 4;
170 	}
171 
172 	*value = val;
173 	err = 0;
174 
175  fail:
176 	mutex_unlock(&sat->mutex);
177 	return err;
178 }
179 
180 static void wf_sat_release(struct kref *ref)
181 {
182 	struct wf_sat *sat = container_of(ref, struct wf_sat, ref);
183 
184 	if (sat->nr >= 0)
185 		sats[sat->nr] = NULL;
186 	kfree(sat);
187 }
188 
189 static void wf_sat_sensor_release(struct wf_sensor *sr)
190 {
191 	struct wf_sat_sensor *sens = wf_to_sat(sr);
192 	struct wf_sat *sat = sens->sat;
193 
194 	kfree(sens);
195 	kref_put(&sat->ref, wf_sat_release);
196 }
197 
198 static const struct wf_sensor_ops wf_sat_ops = {
199 	.get_value	= wf_sat_sensor_get,
200 	.release	= wf_sat_sensor_release,
201 	.owner		= THIS_MODULE,
202 };
203 
204 static int wf_sat_probe(struct i2c_client *client,
205 			const struct i2c_device_id *id)
206 {
207 	struct device_node *dev = client->dev.of_node;
208 	struct wf_sat *sat;
209 	struct wf_sat_sensor *sens;
210 	const u32 *reg;
211 	const char *loc, *type;
212 	u8 chip, core;
213 	struct device_node *child;
214 	int shift, cpu, index;
215 	char *name;
216 	int vsens[2], isens[2];
217 
218 	sat = kzalloc(sizeof(struct wf_sat), GFP_KERNEL);
219 	if (sat == NULL)
220 		return -ENOMEM;
221 	sat->nr = -1;
222 	sat->node = of_node_get(dev);
223 	kref_init(&sat->ref);
224 	mutex_init(&sat->mutex);
225 	sat->i2c = client;
226 	INIT_LIST_HEAD(&sat->sensors);
227 	i2c_set_clientdata(client, sat);
228 
229 	vsens[0] = vsens[1] = -1;
230 	isens[0] = isens[1] = -1;
231 	child = NULL;
232 	while ((child = of_get_next_child(dev, child)) != NULL) {
233 		reg = of_get_property(child, "reg", NULL);
234 		type = of_get_property(child, "device_type", NULL);
235 		loc = of_get_property(child, "location", NULL);
236 		if (reg == NULL || loc == NULL)
237 			continue;
238 
239 		/* the cooked sensors are between 0x30 and 0x37 */
240 		if (*reg < 0x30 || *reg > 0x37)
241 			continue;
242 		index = *reg - 0x30;
243 
244 		/* expect location to be CPU [AB][01] ... */
245 		if (strncmp(loc, "CPU ", 4) != 0)
246 			continue;
247 		chip = loc[4] - 'A';
248 		core = loc[5] - '0';
249 		if (chip > 1 || core > 1) {
250 			printk(KERN_ERR "wf_sat_create: don't understand "
251 			       "location %s for %pOF\n", loc, child);
252 			continue;
253 		}
254 		cpu = 2 * chip + core;
255 		if (sat->nr < 0)
256 			sat->nr = chip;
257 		else if (sat->nr != chip) {
258 			printk(KERN_ERR "wf_sat_create: can't cope with "
259 			       "multiple CPU chips on one SAT (%s)\n", loc);
260 			continue;
261 		}
262 
263 		if (strcmp(type, "voltage-sensor") == 0) {
264 			name = "cpu-voltage";
265 			shift = 4;
266 			vsens[core] = index;
267 		} else if (strcmp(type, "current-sensor") == 0) {
268 			name = "cpu-current";
269 			shift = 8;
270 			isens[core] = index;
271 		} else if (strcmp(type, "temp-sensor") == 0) {
272 			name = "cpu-temp";
273 			shift = 10;
274 		} else
275 			continue;	/* hmmm shouldn't happen */
276 
277 		/* the +16 is enough for "cpu-voltage-n" */
278 		sens = kzalloc(sizeof(struct wf_sat_sensor) + 16, GFP_KERNEL);
279 		if (sens == NULL) {
280 			printk(KERN_ERR "wf_sat_create: couldn't create "
281 			       "%s sensor %d (no memory)\n", name, cpu);
282 			continue;
283 		}
284 		sens->index = index;
285 		sens->index2 = -1;
286 		sens->shift = shift;
287 		sens->sat = sat;
288 		sens->sens.ops = &wf_sat_ops;
289 		sens->sens.name = (char *) (sens + 1);
290 		snprintf((char *)sens->sens.name, 16, "%s-%d", name, cpu);
291 
292 		if (wf_register_sensor(&sens->sens))
293 			kfree(sens);
294 		else {
295 			list_add(&sens->link, &sat->sensors);
296 			kref_get(&sat->ref);
297 		}
298 	}
299 
300 	/* make the power sensors */
301 	for (core = 0; core < 2; ++core) {
302 		if (vsens[core] < 0 || isens[core] < 0)
303 			continue;
304 		cpu = 2 * sat->nr + core;
305 		sens = kzalloc(sizeof(struct wf_sat_sensor) + 16, GFP_KERNEL);
306 		if (sens == NULL) {
307 			printk(KERN_ERR "wf_sat_create: couldn't create power "
308 			       "sensor %d (no memory)\n", cpu);
309 			continue;
310 		}
311 		sens->index = vsens[core];
312 		sens->index2 = isens[core];
313 		sens->shift = 0;
314 		sens->sat = sat;
315 		sens->sens.ops = &wf_sat_ops;
316 		sens->sens.name = (char *) (sens + 1);
317 		snprintf((char *)sens->sens.name, 16, "cpu-power-%d", cpu);
318 
319 		if (wf_register_sensor(&sens->sens))
320 			kfree(sens);
321 		else {
322 			list_add(&sens->link, &sat->sensors);
323 			kref_get(&sat->ref);
324 		}
325 	}
326 
327 	if (sat->nr >= 0)
328 		sats[sat->nr] = sat;
329 
330 	return 0;
331 }
332 
333 static int wf_sat_remove(struct i2c_client *client)
334 {
335 	struct wf_sat *sat = i2c_get_clientdata(client);
336 	struct wf_sat_sensor *sens;
337 
338 	/* release sensors */
339 	while(!list_empty(&sat->sensors)) {
340 		sens = list_first_entry(&sat->sensors,
341 					struct wf_sat_sensor, link);
342 		list_del(&sens->link);
343 		wf_unregister_sensor(&sens->sens);
344 	}
345 	sat->i2c = NULL;
346 	kref_put(&sat->ref, wf_sat_release);
347 
348 	return 0;
349 }
350 
351 static const struct i2c_device_id wf_sat_id[] = {
352 	{ "MAC,smu-sat", 0 },
353 	{ }
354 };
355 MODULE_DEVICE_TABLE(i2c, wf_sat_id);
356 
357 static struct i2c_driver wf_sat_driver = {
358 	.driver = {
359 		.name		= "wf_smu_sat",
360 	},
361 	.probe		= wf_sat_probe,
362 	.remove		= wf_sat_remove,
363 	.id_table	= wf_sat_id,
364 };
365 
366 module_i2c_driver(wf_sat_driver);
367 
368 MODULE_AUTHOR("Paul Mackerras <paulus@samba.org>");
369 MODULE_DESCRIPTION("SMU satellite sensors for PowerMac thermal control");
370 MODULE_LICENSE("GPL");
371