1 /*
2  * (C) 2001  Dave Jones, Arjan van de ven.
3  * (C) 2002 - 2003  Dominik Brodowski <linux@brodo.de>
4  *
5  *  Licensed under the terms of the GNU GPL License version 2.
6  *  Based upon reverse engineered information, and on Intel documentation
7  *  for chipsets ICH2-M and ICH3-M.
8  *
9  *  Many thanks to Ducrot Bruno for finding and fixing the last
10  *  "missing link" for ICH2-M/ICH3-M support, and to Thomas Winkler
11  *  for extensive testing.
12  *
13  *  BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous*
14  */
15 
16 
17 /*********************************************************************
18  *                        SPEEDSTEP - DEFINITIONS                    *
19  *********************************************************************/
20 
21 #include <linux/kernel.h>
22 #include <linux/module.h>
23 #include <linux/init.h>
24 #include <linux/cpufreq.h>
25 #include <linux/pci.h>
26 #include <linux/sched.h>
27 
28 #include <asm/cpu_device_id.h>
29 
30 #include "speedstep-lib.h"
31 
32 
33 /* speedstep_chipset:
34  *   It is necessary to know which chipset is used. As accesses to
35  * this device occur at various places in this module, we need a
36  * static struct pci_dev * pointing to that device.
37  */
38 static struct pci_dev *speedstep_chipset_dev;
39 
40 
41 /* speedstep_processor
42  */
43 static enum speedstep_processor speedstep_processor;
44 
45 static u32 pmbase;
46 
47 /*
48  *   There are only two frequency states for each processor. Values
49  * are in kHz for the time being.
50  */
51 static struct cpufreq_frequency_table speedstep_freqs[] = {
52 	{0, SPEEDSTEP_HIGH,	0},
53 	{0, SPEEDSTEP_LOW,	0},
54 	{0, 0,			CPUFREQ_TABLE_END},
55 };
56 
57 
58 /**
59  * speedstep_find_register - read the PMBASE address
60  *
61  * Returns: -ENODEV if no register could be found
62  */
63 static int speedstep_find_register(void)
64 {
65 	if (!speedstep_chipset_dev)
66 		return -ENODEV;
67 
68 	/* get PMBASE */
69 	pci_read_config_dword(speedstep_chipset_dev, 0x40, &pmbase);
70 	if (!(pmbase & 0x01)) {
71 		printk(KERN_ERR "speedstep-ich: could not find speedstep register\n");
72 		return -ENODEV;
73 	}
74 
75 	pmbase &= 0xFFFFFFFE;
76 	if (!pmbase) {
77 		printk(KERN_ERR "speedstep-ich: could not find speedstep register\n");
78 		return -ENODEV;
79 	}
80 
81 	pr_debug("pmbase is 0x%x\n", pmbase);
82 	return 0;
83 }
84 
85 /**
86  * speedstep_set_state - set the SpeedStep state
87  * @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
88  *
89  *   Tries to change the SpeedStep state.  Can be called from
90  *   smp_call_function_single.
91  */
92 static void speedstep_set_state(unsigned int state)
93 {
94 	u8 pm2_blk;
95 	u8 value;
96 	unsigned long flags;
97 
98 	if (state > 0x1)
99 		return;
100 
101 	/* Disable IRQs */
102 	local_irq_save(flags);
103 
104 	/* read state */
105 	value = inb(pmbase + 0x50);
106 
107 	pr_debug("read at pmbase 0x%x + 0x50 returned 0x%x\n", pmbase, value);
108 
109 	/* write new state */
110 	value &= 0xFE;
111 	value |= state;
112 
113 	pr_debug("writing 0x%x to pmbase 0x%x + 0x50\n", value, pmbase);
114 
115 	/* Disable bus master arbitration */
116 	pm2_blk = inb(pmbase + 0x20);
117 	pm2_blk |= 0x01;
118 	outb(pm2_blk, (pmbase + 0x20));
119 
120 	/* Actual transition */
121 	outb(value, (pmbase + 0x50));
122 
123 	/* Restore bus master arbitration */
124 	pm2_blk &= 0xfe;
125 	outb(pm2_blk, (pmbase + 0x20));
126 
127 	/* check if transition was successful */
128 	value = inb(pmbase + 0x50);
129 
130 	/* Enable IRQs */
131 	local_irq_restore(flags);
132 
133 	pr_debug("read at pmbase 0x%x + 0x50 returned 0x%x\n", pmbase, value);
134 
135 	if (state == (value & 0x1))
136 		pr_debug("change to %u MHz succeeded\n",
137 			speedstep_get_frequency(speedstep_processor) / 1000);
138 	else
139 		printk(KERN_ERR "cpufreq: change failed - I/O error\n");
140 
141 	return;
142 }
143 
144 /* Wrapper for smp_call_function_single. */
145 static void _speedstep_set_state(void *_state)
146 {
147 	speedstep_set_state(*(unsigned int *)_state);
148 }
149 
150 /**
151  * speedstep_activate - activate SpeedStep control in the chipset
152  *
153  *   Tries to activate the SpeedStep status and control registers.
154  * Returns -EINVAL on an unsupported chipset, and zero on success.
155  */
156 static int speedstep_activate(void)
157 {
158 	u16 value = 0;
159 
160 	if (!speedstep_chipset_dev)
161 		return -EINVAL;
162 
163 	pci_read_config_word(speedstep_chipset_dev, 0x00A0, &value);
164 	if (!(value & 0x08)) {
165 		value |= 0x08;
166 		pr_debug("activating SpeedStep (TM) registers\n");
167 		pci_write_config_word(speedstep_chipset_dev, 0x00A0, value);
168 	}
169 
170 	return 0;
171 }
172 
173 
174 /**
175  * speedstep_detect_chipset - detect the Southbridge which contains SpeedStep logic
176  *
177  *   Detects ICH2-M, ICH3-M and ICH4-M so far. The pci_dev points to
178  * the LPC bridge / PM module which contains all power-management
179  * functions. Returns the SPEEDSTEP_CHIPSET_-number for the detected
180  * chipset, or zero on failure.
181  */
182 static unsigned int speedstep_detect_chipset(void)
183 {
184 	speedstep_chipset_dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
185 			      PCI_DEVICE_ID_INTEL_82801DB_12,
186 			      PCI_ANY_ID, PCI_ANY_ID,
187 			      NULL);
188 	if (speedstep_chipset_dev)
189 		return 4; /* 4-M */
190 
191 	speedstep_chipset_dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
192 			      PCI_DEVICE_ID_INTEL_82801CA_12,
193 			      PCI_ANY_ID, PCI_ANY_ID,
194 			      NULL);
195 	if (speedstep_chipset_dev)
196 		return 3; /* 3-M */
197 
198 
199 	speedstep_chipset_dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
200 			      PCI_DEVICE_ID_INTEL_82801BA_10,
201 			      PCI_ANY_ID, PCI_ANY_ID,
202 			      NULL);
203 	if (speedstep_chipset_dev) {
204 		/* speedstep.c causes lockups on Dell Inspirons 8000 and
205 		 * 8100 which use a pretty old revision of the 82815
206 		 * host bridge. Abort on these systems.
207 		 */
208 		static struct pci_dev *hostbridge;
209 
210 		hostbridge  = pci_get_subsys(PCI_VENDOR_ID_INTEL,
211 			      PCI_DEVICE_ID_INTEL_82815_MC,
212 			      PCI_ANY_ID, PCI_ANY_ID,
213 			      NULL);
214 
215 		if (!hostbridge)
216 			return 2; /* 2-M */
217 
218 		if (hostbridge->revision < 5) {
219 			pr_debug("hostbridge does not support speedstep\n");
220 			speedstep_chipset_dev = NULL;
221 			pci_dev_put(hostbridge);
222 			return 0;
223 		}
224 
225 		pci_dev_put(hostbridge);
226 		return 2; /* 2-M */
227 	}
228 
229 	return 0;
230 }
231 
232 static void get_freq_data(void *_speed)
233 {
234 	unsigned int *speed = _speed;
235 
236 	*speed = speedstep_get_frequency(speedstep_processor);
237 }
238 
239 static unsigned int speedstep_get(unsigned int cpu)
240 {
241 	unsigned int speed;
242 
243 	/* You're supposed to ensure CPU is online. */
244 	if (smp_call_function_single(cpu, get_freq_data, &speed, 1) != 0)
245 		BUG();
246 
247 	pr_debug("detected %u kHz as current frequency\n", speed);
248 	return speed;
249 }
250 
251 /**
252  * speedstep_target - set a new CPUFreq policy
253  * @policy: new policy
254  * @index: index of target frequency
255  *
256  * Sets a new CPUFreq policy.
257  */
258 static int speedstep_target(struct cpufreq_policy *policy, unsigned int index)
259 {
260 	unsigned int policy_cpu;
261 
262 	policy_cpu = cpumask_any_and(policy->cpus, cpu_online_mask);
263 
264 	smp_call_function_single(policy_cpu, _speedstep_set_state, &index,
265 				 true);
266 
267 	return 0;
268 }
269 
270 
271 struct get_freqs {
272 	struct cpufreq_policy *policy;
273 	int ret;
274 };
275 
276 static void get_freqs_on_cpu(void *_get_freqs)
277 {
278 	struct get_freqs *get_freqs = _get_freqs;
279 
280 	get_freqs->ret =
281 		speedstep_get_freqs(speedstep_processor,
282 			    &speedstep_freqs[SPEEDSTEP_LOW].frequency,
283 			    &speedstep_freqs[SPEEDSTEP_HIGH].frequency,
284 			    &get_freqs->policy->cpuinfo.transition_latency,
285 			    &speedstep_set_state);
286 }
287 
288 static int speedstep_cpu_init(struct cpufreq_policy *policy)
289 {
290 	unsigned int policy_cpu;
291 	struct get_freqs gf;
292 
293 	/* only run on CPU to be set, or on its sibling */
294 #ifdef CONFIG_SMP
295 	cpumask_copy(policy->cpus, cpu_sibling_mask(policy->cpu));
296 #endif
297 	policy_cpu = cpumask_any_and(policy->cpus, cpu_online_mask);
298 
299 	/* detect low and high frequency and transition latency */
300 	gf.policy = policy;
301 	smp_call_function_single(policy_cpu, get_freqs_on_cpu, &gf, 1);
302 	if (gf.ret)
303 		return gf.ret;
304 
305 	return cpufreq_table_validate_and_show(policy, speedstep_freqs);
306 }
307 
308 
309 static struct cpufreq_driver speedstep_driver = {
310 	.name	= "speedstep-ich",
311 	.verify	= cpufreq_generic_frequency_table_verify,
312 	.target_index = speedstep_target,
313 	.init	= speedstep_cpu_init,
314 	.get	= speedstep_get,
315 	.attr	= cpufreq_generic_attr,
316 };
317 
318 static const struct x86_cpu_id ss_smi_ids[] = {
319 	{ X86_VENDOR_INTEL, 6, 0xb, },
320 	{ X86_VENDOR_INTEL, 6, 0x8, },
321 	{ X86_VENDOR_INTEL, 15, 2 },
322 	{}
323 };
324 #if 0
325 /* Autoload or not? Do not for now. */
326 MODULE_DEVICE_TABLE(x86cpu, ss_smi_ids);
327 #endif
328 
329 /**
330  * speedstep_init - initializes the SpeedStep CPUFreq driver
331  *
332  *   Initializes the SpeedStep support. Returns -ENODEV on unsupported
333  * devices, -EINVAL on problems during initiatization, and zero on
334  * success.
335  */
336 static int __init speedstep_init(void)
337 {
338 	if (!x86_match_cpu(ss_smi_ids))
339 		return -ENODEV;
340 
341 	/* detect processor */
342 	speedstep_processor = speedstep_detect_processor();
343 	if (!speedstep_processor) {
344 		pr_debug("Intel(R) SpeedStep(TM) capable processor "
345 				"not found\n");
346 		return -ENODEV;
347 	}
348 
349 	/* detect chipset */
350 	if (!speedstep_detect_chipset()) {
351 		pr_debug("Intel(R) SpeedStep(TM) for this chipset not "
352 				"(yet) available.\n");
353 		return -ENODEV;
354 	}
355 
356 	/* activate speedstep support */
357 	if (speedstep_activate()) {
358 		pci_dev_put(speedstep_chipset_dev);
359 		return -EINVAL;
360 	}
361 
362 	if (speedstep_find_register())
363 		return -ENODEV;
364 
365 	return cpufreq_register_driver(&speedstep_driver);
366 }
367 
368 
369 /**
370  * speedstep_exit - unregisters SpeedStep support
371  *
372  *   Unregisters SpeedStep support.
373  */
374 static void __exit speedstep_exit(void)
375 {
376 	pci_dev_put(speedstep_chipset_dev);
377 	cpufreq_unregister_driver(&speedstep_driver);
378 }
379 
380 
381 MODULE_AUTHOR("Dave Jones, Dominik Brodowski <linux@brodo.de>");
382 MODULE_DESCRIPTION("Speedstep driver for Intel mobile processors on chipsets "
383 		"with ICH-M southbridges.");
384 MODULE_LICENSE("GPL");
385 
386 module_init(speedstep_init);
387 module_exit(speedstep_exit);
388