1 // SPDX-License-Identifier: GPL-2.0-only
3 * CPPC (Collaborative Processor Performance Control) driver for
4 * interfacing with the CPUfreq layer and governors. See
5 * cppc_acpi.c for CPPC specific methods.
7 * (C) Copyright 2014, 2015 Linaro Ltd.
8 * Author: Ashwin Chaugule <ashwin.chaugule@linaro.org>
11 #define pr_fmt(fmt) "CPPC Cpufreq:" fmt
13 #include <linux/kernel.h>
14 #include <linux/module.h>
15 #include <linux/delay.h>
16 #include <linux/cpu.h>
17 #include <linux/cpufreq.h>
18 #include <linux/dmi.h>
19 #include <linux/time.h>
20 #include <linux/vmalloc.h>
22 #include <asm/unaligned.h>
24 #include <acpi/cppc_acpi.h>
26 /* Minimum struct length needed for the DMI processor entry we want */
27 #define DMI_ENTRY_PROCESSOR_MIN_LENGTH 48
29 /* Offest in the DMI processor structure for the max frequency */
30 #define DMI_PROCESSOR_MAX_SPEED 0x14
33 * These structs contain information parsed from per CPU
34 * ACPI _CPC structures.
35 * e.g. For each CPU the highest, lowest supported
36 * performance capabilities, desired performance level
39 static struct cppc_cpudata **all_cpu_data;
40 static bool boost_supported;
42 struct cppc_workaround_oem_info {
43 char oem_id[ACPI_OEM_ID_SIZE + 1];
44 char oem_table_id[ACPI_OEM_TABLE_ID_SIZE + 1];
48 static struct cppc_workaround_oem_info wa_info[] = {
51 .oem_table_id = "HIP07 ",
55 .oem_table_id = "HIP08 ",
60 /* Callback function used to retrieve the max frequency from DMI */
61 static void cppc_find_dmi_mhz(const struct dmi_header *dm, void *private)
63 const u8 *dmi_data = (const u8 *)dm;
64 u16 *mhz = (u16 *)private;
66 if (dm->type == DMI_ENTRY_PROCESSOR &&
67 dm->length >= DMI_ENTRY_PROCESSOR_MIN_LENGTH) {
68 u16 val = (u16)get_unaligned((const u16 *)
69 (dmi_data + DMI_PROCESSOR_MAX_SPEED));
70 *mhz = val > *mhz ? val : *mhz;
74 /* Look up the max frequency in DMI */
75 static u64 cppc_get_dmi_max_khz(void)
79 dmi_walk(cppc_find_dmi_mhz, &mhz);
82 * Real stupid fallback value, just in case there is no
91 * If CPPC lowest_freq and nominal_freq registers are exposed then we can
92 * use them to convert perf to freq and vice versa
94 * If the perf/freq point lies between Nominal and Lowest, we can treat
95 * (Low perf, Low freq) and (Nom Perf, Nom freq) as 2D co-ordinates of a line
96 * and extrapolate the rest
97 * For perf/freq > Nominal, we use the ratio perf:freq at Nominal for conversion
99 static unsigned int cppc_cpufreq_perf_to_khz(struct cppc_cpudata *cpu,
103 struct cppc_perf_caps *caps = &cpu->perf_caps;
106 if (caps->lowest_freq && caps->nominal_freq) {
107 if (perf >= caps->nominal_perf) {
108 mul = caps->nominal_freq;
109 div = caps->nominal_perf;
111 mul = caps->nominal_freq - caps->lowest_freq;
112 div = caps->nominal_perf - caps->lowest_perf;
116 max_khz = cppc_get_dmi_max_khz();
118 div = caps->highest_perf;
120 return (u64)perf * mul / div;
123 static unsigned int cppc_cpufreq_khz_to_perf(struct cppc_cpudata *cpu,
127 struct cppc_perf_caps *caps = &cpu->perf_caps;
130 if (caps->lowest_freq && caps->nominal_freq) {
131 if (freq >= caps->nominal_freq) {
132 mul = caps->nominal_perf;
133 div = caps->nominal_freq;
135 mul = caps->lowest_perf;
136 div = caps->lowest_freq;
140 max_khz = cppc_get_dmi_max_khz();
141 mul = caps->highest_perf;
145 return (u64)freq * mul / div;
148 static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
149 unsigned int target_freq,
150 unsigned int relation)
152 struct cppc_cpudata *cpu;
153 struct cpufreq_freqs freqs;
157 cpu = all_cpu_data[policy->cpu];
159 desired_perf = cppc_cpufreq_khz_to_perf(cpu, target_freq);
160 /* Return if it is exactly the same perf */
161 if (desired_perf == cpu->perf_ctrls.desired_perf)
164 cpu->perf_ctrls.desired_perf = desired_perf;
165 freqs.old = policy->cur;
166 freqs.new = target_freq;
168 cpufreq_freq_transition_begin(policy, &freqs);
169 ret = cppc_set_perf(cpu->cpu, &cpu->perf_ctrls);
170 cpufreq_freq_transition_end(policy, &freqs, ret != 0);
173 pr_debug("Failed to set target on CPU:%d. ret:%d\n",
179 static int cppc_verify_policy(struct cpufreq_policy_data *policy)
181 cpufreq_verify_within_cpu_limits(policy);
185 static void cppc_cpufreq_stop_cpu(struct cpufreq_policy *policy)
187 int cpu_num = policy->cpu;
188 struct cppc_cpudata *cpu = all_cpu_data[cpu_num];
191 cpu->perf_ctrls.desired_perf = cpu->perf_caps.lowest_perf;
193 ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
195 pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
196 cpu->perf_caps.lowest_perf, cpu_num, ret);
200 * The PCC subspace describes the rate at which platform can accept commands
201 * on the shared PCC channel (including READs which do not count towards freq
202 * trasition requests), so ideally we need to use the PCC values as a fallback
203 * if we don't have a platform specific transition_delay_us
206 #include <asm/cputype.h>
208 static unsigned int cppc_cpufreq_get_transition_delay_us(int cpu)
210 unsigned long implementor = read_cpuid_implementor();
211 unsigned long part_num = read_cpuid_part_number();
212 unsigned int delay_us = 0;
214 switch (implementor) {
215 case ARM_CPU_IMP_QCOM:
217 case QCOM_CPU_PART_FALKOR_V1:
218 case QCOM_CPU_PART_FALKOR:
222 delay_us = cppc_get_transition_latency(cpu) / NSEC_PER_USEC;
227 delay_us = cppc_get_transition_latency(cpu) / NSEC_PER_USEC;
236 static unsigned int cppc_cpufreq_get_transition_delay_us(int cpu)
238 return cppc_get_transition_latency(cpu) / NSEC_PER_USEC;
242 static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
244 struct cppc_cpudata *cpu;
245 unsigned int cpu_num = policy->cpu;
248 cpu = all_cpu_data[policy->cpu];
251 ret = cppc_get_perf_caps(policy->cpu, &cpu->perf_caps);
254 pr_debug("Err reading CPU%d perf capabilities. ret:%d\n",
259 /* Convert the lowest and nominal freq from MHz to KHz */
260 cpu->perf_caps.lowest_freq *= 1000;
261 cpu->perf_caps.nominal_freq *= 1000;
264 * Set min to lowest nonlinear perf to avoid any efficiency penalty (see
265 * Section 8.4.7.1.1.5 of ACPI 6.1 spec)
267 policy->min = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.lowest_nonlinear_perf);
268 policy->max = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.nominal_perf);
271 * Set cpuinfo.min_freq to Lowest to make the full range of performance
272 * available if userspace wants to use any perf between lowest & lowest
275 policy->cpuinfo.min_freq = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.lowest_perf);
276 policy->cpuinfo.max_freq = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.nominal_perf);
278 policy->transition_delay_us = cppc_cpufreq_get_transition_delay_us(cpu_num);
279 policy->shared_type = cpu->shared_type;
281 if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY) {
284 cpumask_copy(policy->cpus, cpu->shared_cpu_map);
286 for_each_cpu(i, policy->cpus) {
287 if (unlikely(i == policy->cpu))
290 memcpy(&all_cpu_data[i]->perf_caps, &cpu->perf_caps,
291 sizeof(cpu->perf_caps));
293 } else if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL) {
294 /* Support only SW_ANY for now. */
295 pr_debug("Unsupported CPU co-ord type\n");
299 cpu->cur_policy = policy;
302 * If 'highest_perf' is greater than 'nominal_perf', we assume CPU Boost
305 if (cpu->perf_caps.highest_perf > cpu->perf_caps.nominal_perf)
306 boost_supported = true;
308 /* Set policy->cur to max now. The governors will adjust later. */
309 policy->cur = cppc_cpufreq_perf_to_khz(cpu,
310 cpu->perf_caps.highest_perf);
311 cpu->perf_ctrls.desired_perf = cpu->perf_caps.highest_perf;
313 ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
315 pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
316 cpu->perf_caps.highest_perf, cpu_num, ret);
321 static inline u64 get_delta(u64 t1, u64 t0)
323 if (t1 > t0 || t0 > ~(u32)0)
326 return (u32)t1 - (u32)t0;
329 static int cppc_get_rate_from_fbctrs(struct cppc_cpudata *cpu,
330 struct cppc_perf_fb_ctrs fb_ctrs_t0,
331 struct cppc_perf_fb_ctrs fb_ctrs_t1)
333 u64 delta_reference, delta_delivered;
334 u64 reference_perf, delivered_perf;
336 reference_perf = fb_ctrs_t0.reference_perf;
338 delta_reference = get_delta(fb_ctrs_t1.reference,
339 fb_ctrs_t0.reference);
340 delta_delivered = get_delta(fb_ctrs_t1.delivered,
341 fb_ctrs_t0.delivered);
343 /* Check to avoid divide-by zero */
344 if (delta_reference || delta_delivered)
345 delivered_perf = (reference_perf * delta_delivered) /
348 delivered_perf = cpu->perf_ctrls.desired_perf;
350 return cppc_cpufreq_perf_to_khz(cpu, delivered_perf);
353 static unsigned int cppc_cpufreq_get_rate(unsigned int cpunum)
355 struct cppc_perf_fb_ctrs fb_ctrs_t0 = {0}, fb_ctrs_t1 = {0};
356 struct cppc_cpudata *cpu = all_cpu_data[cpunum];
359 ret = cppc_get_perf_ctrs(cpunum, &fb_ctrs_t0);
363 udelay(2); /* 2usec delay between sampling */
365 ret = cppc_get_perf_ctrs(cpunum, &fb_ctrs_t1);
369 return cppc_get_rate_from_fbctrs(cpu, fb_ctrs_t0, fb_ctrs_t1);
372 static int cppc_cpufreq_set_boost(struct cpufreq_policy *policy, int state)
374 struct cppc_cpudata *cpudata;
377 if (!boost_supported) {
378 pr_err("BOOST not supported by CPU or firmware\n");
382 cpudata = all_cpu_data[policy->cpu];
384 policy->max = cppc_cpufreq_perf_to_khz(cpudata,
385 cpudata->perf_caps.highest_perf);
387 policy->max = cppc_cpufreq_perf_to_khz(cpudata,
388 cpudata->perf_caps.nominal_perf);
389 policy->cpuinfo.max_freq = policy->max;
391 ret = freq_qos_update_request(policy->max_freq_req, policy->max);
398 static struct cpufreq_driver cppc_cpufreq_driver = {
399 .flags = CPUFREQ_CONST_LOOPS,
400 .verify = cppc_verify_policy,
401 .target = cppc_cpufreq_set_target,
402 .get = cppc_cpufreq_get_rate,
403 .init = cppc_cpufreq_cpu_init,
404 .stop_cpu = cppc_cpufreq_stop_cpu,
405 .set_boost = cppc_cpufreq_set_boost,
406 .name = "cppc_cpufreq",
410 * HISI platform does not support delivered performance counter and
411 * reference performance counter. It can calculate the performance using the
412 * platform specific mechanism. We reuse the desired performance register to
413 * store the real performance calculated by the platform.
415 static unsigned int hisi_cppc_cpufreq_get_rate(unsigned int cpunum)
417 struct cppc_cpudata *cpudata = all_cpu_data[cpunum];
421 ret = cppc_get_desired_perf(cpunum, &desired_perf);
425 return cppc_cpufreq_perf_to_khz(cpudata, desired_perf);
428 static void cppc_check_hisi_workaround(void)
430 struct acpi_table_header *tbl;
431 acpi_status status = AE_OK;
434 status = acpi_get_table(ACPI_SIG_PCCT, 0, &tbl);
435 if (ACPI_FAILURE(status) || !tbl)
438 for (i = 0; i < ARRAY_SIZE(wa_info); i++) {
439 if (!memcmp(wa_info[i].oem_id, tbl->oem_id, ACPI_OEM_ID_SIZE) &&
440 !memcmp(wa_info[i].oem_table_id, tbl->oem_table_id, ACPI_OEM_TABLE_ID_SIZE) &&
441 wa_info[i].oem_revision == tbl->oem_revision) {
442 /* Overwrite the get() callback */
443 cppc_cpufreq_driver.get = hisi_cppc_cpufreq_get_rate;
451 static int __init cppc_cpufreq_init(void)
454 struct cppc_cpudata *cpu;
459 all_cpu_data = kcalloc(num_possible_cpus(), sizeof(void *),
464 for_each_possible_cpu(i) {
465 all_cpu_data[i] = kzalloc(sizeof(struct cppc_cpudata), GFP_KERNEL);
466 if (!all_cpu_data[i])
469 cpu = all_cpu_data[i];
470 if (!zalloc_cpumask_var(&cpu->shared_cpu_map, GFP_KERNEL))
474 ret = acpi_get_psd_map(all_cpu_data);
476 pr_debug("Error parsing PSD data. Aborting cpufreq registration.\n");
480 cppc_check_hisi_workaround();
482 ret = cpufreq_register_driver(&cppc_cpufreq_driver);
489 for_each_possible_cpu(i) {
490 cpu = all_cpu_data[i];
493 free_cpumask_var(cpu->shared_cpu_map);
501 static void __exit cppc_cpufreq_exit(void)
503 struct cppc_cpudata *cpu;
506 cpufreq_unregister_driver(&cppc_cpufreq_driver);
508 for_each_possible_cpu(i) {
509 cpu = all_cpu_data[i];
510 free_cpumask_var(cpu->shared_cpu_map);
517 module_exit(cppc_cpufreq_exit);
518 MODULE_AUTHOR("Ashwin Chaugule");
519 MODULE_DESCRIPTION("CPUFreq driver based on the ACPI CPPC v5.0+ spec");
520 MODULE_LICENSE("GPL");
522 late_initcall(cppc_cpufreq_init);
524 static const struct acpi_device_id cppc_acpi_ids[] __used = {
525 {ACPI_PROCESSOR_DEVICE_HID, },
529 MODULE_DEVICE_TABLE(acpi, cppc_acpi_ids);