1 // SPDX-License-Identifier: GPL-2.0-only
3 * (C) 2001 Dave Jones, Arjan van de ven.
4 * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
6 * Based upon reverse engineered information, and on Intel documentation
7 * for chipsets ICH2-M and ICH3-M.
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.
13 * BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous*
17 /*********************************************************************
18 * SPEEDSTEP - DEFINITIONS *
19 *********************************************************************/
21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
23 #include <linux/kernel.h>
24 #include <linux/module.h>
25 #include <linux/init.h>
26 #include <linux/cpufreq.h>
27 #include <linux/pci.h>
28 #include <linux/sched.h>
30 #include <asm/cpu_device_id.h>
32 #include "speedstep-lib.h"
36 * It is necessary to know which chipset is used. As accesses to
37 * this device occur at various places in this module, we need a
38 * static struct pci_dev * pointing to that device.
40 static struct pci_dev
*speedstep_chipset_dev
;
43 /* speedstep_processor
45 static enum speedstep_processor speedstep_processor
;
50 * There are only two frequency states for each processor. Values
51 * are in kHz for the time being.
53 static struct cpufreq_frequency_table speedstep_freqs
[] = {
54 {0, SPEEDSTEP_HIGH
, 0},
55 {0, SPEEDSTEP_LOW
, 0},
56 {0, 0, CPUFREQ_TABLE_END
},
61 * speedstep_find_register - read the PMBASE address
63 * Returns: -ENODEV if no register could be found
65 static int speedstep_find_register(void)
67 if (!speedstep_chipset_dev
)
71 pci_read_config_dword(speedstep_chipset_dev
, 0x40, &pmbase
);
72 if (!(pmbase
& 0x01)) {
73 pr_err("could not find speedstep register\n");
79 pr_err("could not find speedstep register\n");
83 pr_debug("pmbase is 0x%x\n", pmbase
);
88 * speedstep_set_state - set the SpeedStep state
89 * @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
91 * Tries to change the SpeedStep state. Can be called from
92 * smp_call_function_single.
94 static void speedstep_set_state(unsigned int state
)
104 local_irq_save(flags
);
107 value
= inb(pmbase
+ 0x50);
109 pr_debug("read at pmbase 0x%x + 0x50 returned 0x%x\n", pmbase
, value
);
111 /* write new state */
115 pr_debug("writing 0x%x to pmbase 0x%x + 0x50\n", value
, pmbase
);
117 /* Disable bus master arbitration */
118 pm2_blk
= inb(pmbase
+ 0x20);
120 outb(pm2_blk
, (pmbase
+ 0x20));
122 /* Actual transition */
123 outb(value
, (pmbase
+ 0x50));
125 /* Restore bus master arbitration */
127 outb(pm2_blk
, (pmbase
+ 0x20));
129 /* check if transition was successful */
130 value
= inb(pmbase
+ 0x50);
133 local_irq_restore(flags
);
135 pr_debug("read at pmbase 0x%x + 0x50 returned 0x%x\n", pmbase
, value
);
137 if (state
== (value
& 0x1))
138 pr_debug("change to %u MHz succeeded\n",
139 speedstep_get_frequency(speedstep_processor
) / 1000);
141 pr_err("change failed - I/O error\n");
146 /* Wrapper for smp_call_function_single. */
147 static void _speedstep_set_state(void *_state
)
149 speedstep_set_state(*(unsigned int *)_state
);
153 * speedstep_activate - activate SpeedStep control in the chipset
155 * Tries to activate the SpeedStep status and control registers.
156 * Returns -EINVAL on an unsupported chipset, and zero on success.
158 static int speedstep_activate(void)
162 if (!speedstep_chipset_dev
)
165 pci_read_config_word(speedstep_chipset_dev
, 0x00A0, &value
);
166 if (!(value
& 0x08)) {
168 pr_debug("activating SpeedStep (TM) registers\n");
169 pci_write_config_word(speedstep_chipset_dev
, 0x00A0, value
);
177 * speedstep_detect_chipset - detect the Southbridge which contains SpeedStep logic
179 * Detects ICH2-M, ICH3-M and ICH4-M so far. The pci_dev points to
180 * the LPC bridge / PM module which contains all power-management
181 * functions. Returns the SPEEDSTEP_CHIPSET_-number for the detected
182 * chipset, or zero on failure.
184 static unsigned int speedstep_detect_chipset(void)
186 speedstep_chipset_dev
= pci_get_subsys(PCI_VENDOR_ID_INTEL
,
187 PCI_DEVICE_ID_INTEL_82801DB_12
,
188 PCI_ANY_ID
, PCI_ANY_ID
,
190 if (speedstep_chipset_dev
)
193 speedstep_chipset_dev
= pci_get_subsys(PCI_VENDOR_ID_INTEL
,
194 PCI_DEVICE_ID_INTEL_82801CA_12
,
195 PCI_ANY_ID
, PCI_ANY_ID
,
197 if (speedstep_chipset_dev
)
201 speedstep_chipset_dev
= pci_get_subsys(PCI_VENDOR_ID_INTEL
,
202 PCI_DEVICE_ID_INTEL_82801BA_10
,
203 PCI_ANY_ID
, PCI_ANY_ID
,
205 if (speedstep_chipset_dev
) {
206 /* speedstep.c causes lockups on Dell Inspirons 8000 and
207 * 8100 which use a pretty old revision of the 82815
208 * host bridge. Abort on these systems.
210 struct pci_dev
*hostbridge
;
212 hostbridge
= pci_get_subsys(PCI_VENDOR_ID_INTEL
,
213 PCI_DEVICE_ID_INTEL_82815_MC
,
214 PCI_ANY_ID
, PCI_ANY_ID
,
220 if (hostbridge
->revision
< 5) {
221 pr_debug("hostbridge does not support speedstep\n");
222 speedstep_chipset_dev
= NULL
;
223 pci_dev_put(hostbridge
);
227 pci_dev_put(hostbridge
);
234 static void get_freq_data(void *_speed
)
236 unsigned int *speed
= _speed
;
238 *speed
= speedstep_get_frequency(speedstep_processor
);
241 static unsigned int speedstep_get(unsigned int cpu
)
245 /* You're supposed to ensure CPU is online. */
246 BUG_ON(smp_call_function_single(cpu
, get_freq_data
, &speed
, 1));
248 pr_debug("detected %u kHz as current frequency\n", speed
);
253 * speedstep_target - set a new CPUFreq policy
254 * @policy: new policy
255 * @index: index of target frequency
257 * Sets a new CPUFreq policy.
259 static int speedstep_target(struct cpufreq_policy
*policy
, unsigned int index
)
261 unsigned int policy_cpu
;
263 policy_cpu
= cpumask_any_and(policy
->cpus
, cpu_online_mask
);
265 smp_call_function_single(policy_cpu
, _speedstep_set_state
, &index
,
273 struct cpufreq_policy
*policy
;
277 static void get_freqs_on_cpu(void *_get_freqs
)
279 struct get_freqs
*get_freqs
= _get_freqs
;
282 speedstep_get_freqs(speedstep_processor
,
283 &speedstep_freqs
[SPEEDSTEP_LOW
].frequency
,
284 &speedstep_freqs
[SPEEDSTEP_HIGH
].frequency
,
285 &get_freqs
->policy
->cpuinfo
.transition_latency
,
286 &speedstep_set_state
);
289 static int speedstep_cpu_init(struct cpufreq_policy
*policy
)
291 unsigned int policy_cpu
;
294 /* only run on CPU to be set, or on its sibling */
296 cpumask_copy(policy
->cpus
, topology_sibling_cpumask(policy
->cpu
));
298 policy_cpu
= cpumask_any_and(policy
->cpus
, cpu_online_mask
);
300 /* detect low and high frequency and transition latency */
302 smp_call_function_single(policy_cpu
, get_freqs_on_cpu
, &gf
, 1);
306 policy
->freq_table
= speedstep_freqs
;
312 static struct cpufreq_driver speedstep_driver
= {
313 .name
= "speedstep-ich",
314 .verify
= cpufreq_generic_frequency_table_verify
,
315 .target_index
= speedstep_target
,
316 .init
= speedstep_cpu_init
,
317 .get
= speedstep_get
,
318 .attr
= cpufreq_generic_attr
,
321 static const struct x86_cpu_id ss_smi_ids
[] = {
322 { X86_VENDOR_INTEL
, 6, 0xb, },
323 { X86_VENDOR_INTEL
, 6, 0x8, },
324 { X86_VENDOR_INTEL
, 15, 2 },
328 /* Autoload or not? Do not for now. */
329 MODULE_DEVICE_TABLE(x86cpu
, ss_smi_ids
);
333 * speedstep_init - initializes the SpeedStep CPUFreq driver
335 * Initializes the SpeedStep support. Returns -ENODEV on unsupported
336 * devices, -EINVAL on problems during initiatization, and zero on
339 static int __init
speedstep_init(void)
341 if (!x86_match_cpu(ss_smi_ids
))
344 /* detect processor */
345 speedstep_processor
= speedstep_detect_processor();
346 if (!speedstep_processor
) {
347 pr_debug("Intel(R) SpeedStep(TM) capable processor "
353 if (!speedstep_detect_chipset()) {
354 pr_debug("Intel(R) SpeedStep(TM) for this chipset not "
355 "(yet) available.\n");
359 /* activate speedstep support */
360 if (speedstep_activate()) {
361 pci_dev_put(speedstep_chipset_dev
);
365 if (speedstep_find_register())
368 return cpufreq_register_driver(&speedstep_driver
);
373 * speedstep_exit - unregisters SpeedStep support
375 * Unregisters SpeedStep support.
377 static void __exit
speedstep_exit(void)
379 pci_dev_put(speedstep_chipset_dev
);
380 cpufreq_unregister_driver(&speedstep_driver
);
384 MODULE_AUTHOR("Dave Jones, Dominik Brodowski <linux@brodo.de>");
385 MODULE_DESCRIPTION("Speedstep driver for Intel mobile processors on chipsets "
386 "with ICH-M southbridges.");
387 MODULE_LICENSE("GPL");
389 module_init(speedstep_init
);
390 module_exit(speedstep_exit
);