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;
41 struct cppc_workaround_oem_info {
42 char oem_id[ACPI_OEM_ID_SIZE +1];
43 char oem_table_id[ACPI_OEM_TABLE_ID_SIZE + 1];
47 static bool apply_hisi_workaround;
49 static struct cppc_workaround_oem_info wa_info[] = {
52 .oem_table_id = "HIP07 ",
56 .oem_table_id = "HIP08 ",
61 static unsigned int cppc_cpufreq_perf_to_khz(struct cppc_cpudata *cpu,
65 * HISI platform does not support delivered performance counter and
66 * reference performance counter. It can calculate the performance using the
67 * platform specific mechanism. We reuse the desired performance register to
68 * store the real performance calculated by the platform.
70 static unsigned int hisi_cppc_cpufreq_get_rate(unsigned int cpunum)
72 struct cppc_cpudata *cpudata = all_cpu_data[cpunum];
76 ret = cppc_get_desired_perf(cpunum, &desired_perf);
80 return cppc_cpufreq_perf_to_khz(cpudata, desired_perf);
83 static void cppc_check_hisi_workaround(void)
85 struct acpi_table_header *tbl;
86 acpi_status status = AE_OK;
89 status = acpi_get_table(ACPI_SIG_PCCT, 0, &tbl);
90 if (ACPI_FAILURE(status) || !tbl)
93 for (i = 0; i < ARRAY_SIZE(wa_info); i++) {
94 if (!memcmp(wa_info[i].oem_id, tbl->oem_id, ACPI_OEM_ID_SIZE) &&
95 !memcmp(wa_info[i].oem_table_id, tbl->oem_table_id, ACPI_OEM_TABLE_ID_SIZE) &&
96 wa_info[i].oem_revision == tbl->oem_revision)
97 apply_hisi_workaround = true;
101 /* Callback function used to retrieve the max frequency from DMI */
102 static void cppc_find_dmi_mhz(const struct dmi_header *dm, void *private)
104 const u8 *dmi_data = (const u8 *)dm;
105 u16 *mhz = (u16 *)private;
107 if (dm->type == DMI_ENTRY_PROCESSOR &&
108 dm->length >= DMI_ENTRY_PROCESSOR_MIN_LENGTH) {
109 u16 val = (u16)get_unaligned((const u16 *)
110 (dmi_data + DMI_PROCESSOR_MAX_SPEED));
111 *mhz = val > *mhz ? val : *mhz;
115 /* Look up the max frequency in DMI */
116 static u64 cppc_get_dmi_max_khz(void)
120 dmi_walk(cppc_find_dmi_mhz, &mhz);
123 * Real stupid fallback value, just in case there is no
132 * If CPPC lowest_freq and nominal_freq registers are exposed then we can
133 * use them to convert perf to freq and vice versa
135 * If the perf/freq point lies between Nominal and Lowest, we can treat
136 * (Low perf, Low freq) and (Nom Perf, Nom freq) as 2D co-ordinates of a line
137 * and extrapolate the rest
138 * For perf/freq > Nominal, we use the ratio perf:freq at Nominal for conversion
140 static unsigned int cppc_cpufreq_perf_to_khz(struct cppc_cpudata *cpu,
144 struct cppc_perf_caps *caps = &cpu->perf_caps;
147 if (caps->lowest_freq && caps->nominal_freq) {
148 if (perf >= caps->nominal_perf) {
149 mul = caps->nominal_freq;
150 div = caps->nominal_perf;
152 mul = caps->nominal_freq - caps->lowest_freq;
153 div = caps->nominal_perf - caps->lowest_perf;
157 max_khz = cppc_get_dmi_max_khz();
159 div = cpu->perf_caps.highest_perf;
161 return (u64)perf * mul / div;
164 static unsigned int cppc_cpufreq_khz_to_perf(struct cppc_cpudata *cpu,
168 struct cppc_perf_caps *caps = &cpu->perf_caps;
171 if (caps->lowest_freq && caps->nominal_freq) {
172 if (freq >= caps->nominal_freq) {
173 mul = caps->nominal_perf;
174 div = caps->nominal_freq;
176 mul = caps->lowest_perf;
177 div = caps->lowest_freq;
181 max_khz = cppc_get_dmi_max_khz();
182 mul = cpu->perf_caps.highest_perf;
186 return (u64)freq * mul / div;
189 static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
190 unsigned int target_freq,
191 unsigned int relation)
193 struct cppc_cpudata *cpu;
194 struct cpufreq_freqs freqs;
198 cpu = all_cpu_data[policy->cpu];
200 desired_perf = cppc_cpufreq_khz_to_perf(cpu, target_freq);
201 /* Return if it is exactly the same perf */
202 if (desired_perf == cpu->perf_ctrls.desired_perf)
205 cpu->perf_ctrls.desired_perf = desired_perf;
206 freqs.old = policy->cur;
207 freqs.new = target_freq;
209 cpufreq_freq_transition_begin(policy, &freqs);
210 ret = cppc_set_perf(cpu->cpu, &cpu->perf_ctrls);
211 cpufreq_freq_transition_end(policy, &freqs, ret != 0);
214 pr_debug("Failed to set target on CPU:%d. ret:%d\n",
220 static int cppc_verify_policy(struct cpufreq_policy *policy)
222 cpufreq_verify_within_cpu_limits(policy);
226 static void cppc_cpufreq_stop_cpu(struct cpufreq_policy *policy)
228 int cpu_num = policy->cpu;
229 struct cppc_cpudata *cpu = all_cpu_data[cpu_num];
232 cpu->perf_ctrls.desired_perf = cpu->perf_caps.lowest_perf;
234 ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
236 pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
237 cpu->perf_caps.lowest_perf, cpu_num, ret);
241 * The PCC subspace describes the rate at which platform can accept commands
242 * on the shared PCC channel (including READs which do not count towards freq
243 * trasition requests), so ideally we need to use the PCC values as a fallback
244 * if we don't have a platform specific transition_delay_us
247 #include <asm/cputype.h>
249 static unsigned int cppc_cpufreq_get_transition_delay_us(int cpu)
251 unsigned long implementor = read_cpuid_implementor();
252 unsigned long part_num = read_cpuid_part_number();
253 unsigned int delay_us = 0;
255 switch (implementor) {
256 case ARM_CPU_IMP_QCOM:
258 case QCOM_CPU_PART_FALKOR_V1:
259 case QCOM_CPU_PART_FALKOR:
263 delay_us = cppc_get_transition_latency(cpu) / NSEC_PER_USEC;
268 delay_us = cppc_get_transition_latency(cpu) / NSEC_PER_USEC;
277 static unsigned int cppc_cpufreq_get_transition_delay_us(int cpu)
279 return cppc_get_transition_latency(cpu) / NSEC_PER_USEC;
283 static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
285 struct cppc_cpudata *cpu;
286 unsigned int cpu_num = policy->cpu;
289 cpu = all_cpu_data[policy->cpu];
292 ret = cppc_get_perf_caps(policy->cpu, &cpu->perf_caps);
295 pr_debug("Err reading CPU%d perf capabilities. ret:%d\n",
300 /* Convert the lowest and nominal freq from MHz to KHz */
301 cpu->perf_caps.lowest_freq *= 1000;
302 cpu->perf_caps.nominal_freq *= 1000;
305 * Set min to lowest nonlinear perf to avoid any efficiency penalty (see
306 * Section 8.4.7.1.1.5 of ACPI 6.1 spec)
308 policy->min = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.lowest_nonlinear_perf);
309 policy->max = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.highest_perf);
312 * Set cpuinfo.min_freq to Lowest to make the full range of performance
313 * available if userspace wants to use any perf between lowest & lowest
316 policy->cpuinfo.min_freq = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.lowest_perf);
317 policy->cpuinfo.max_freq = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.highest_perf);
319 policy->transition_delay_us = cppc_cpufreq_get_transition_delay_us(cpu_num);
320 policy->shared_type = cpu->shared_type;
322 if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY) {
325 cpumask_copy(policy->cpus, cpu->shared_cpu_map);
327 for_each_cpu(i, policy->cpus) {
328 if (unlikely(i == policy->cpu))
331 memcpy(&all_cpu_data[i]->perf_caps, &cpu->perf_caps,
332 sizeof(cpu->perf_caps));
334 } else if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL) {
335 /* Support only SW_ANY for now. */
336 pr_debug("Unsupported CPU co-ord type\n");
340 cpu->cur_policy = policy;
342 /* Set policy->cur to max now. The governors will adjust later. */
343 policy->cur = cppc_cpufreq_perf_to_khz(cpu,
344 cpu->perf_caps.highest_perf);
345 cpu->perf_ctrls.desired_perf = cpu->perf_caps.highest_perf;
347 ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
349 pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
350 cpu->perf_caps.highest_perf, cpu_num, ret);
355 static inline u64 get_delta(u64 t1, u64 t0)
357 if (t1 > t0 || t0 > ~(u32)0)
360 return (u32)t1 - (u32)t0;
363 static int cppc_get_rate_from_fbctrs(struct cppc_cpudata *cpu,
364 struct cppc_perf_fb_ctrs fb_ctrs_t0,
365 struct cppc_perf_fb_ctrs fb_ctrs_t1)
367 u64 delta_reference, delta_delivered;
368 u64 reference_perf, delivered_perf;
370 reference_perf = fb_ctrs_t0.reference_perf;
372 delta_reference = get_delta(fb_ctrs_t1.reference,
373 fb_ctrs_t0.reference);
374 delta_delivered = get_delta(fb_ctrs_t1.delivered,
375 fb_ctrs_t0.delivered);
377 /* Check to avoid divide-by zero */
378 if (delta_reference || delta_delivered)
379 delivered_perf = (reference_perf * delta_delivered) /
382 delivered_perf = cpu->perf_ctrls.desired_perf;
384 return cppc_cpufreq_perf_to_khz(cpu, delivered_perf);
387 static unsigned int cppc_cpufreq_get_rate(unsigned int cpunum)
389 struct cppc_perf_fb_ctrs fb_ctrs_t0 = {0}, fb_ctrs_t1 = {0};
390 struct cppc_cpudata *cpu = all_cpu_data[cpunum];
393 if (apply_hisi_workaround)
394 return hisi_cppc_cpufreq_get_rate(cpunum);
396 ret = cppc_get_perf_ctrs(cpunum, &fb_ctrs_t0);
400 udelay(2); /* 2usec delay between sampling */
402 ret = cppc_get_perf_ctrs(cpunum, &fb_ctrs_t1);
406 return cppc_get_rate_from_fbctrs(cpu, fb_ctrs_t0, fb_ctrs_t1);
409 static struct cpufreq_driver cppc_cpufreq_driver = {
410 .flags = CPUFREQ_CONST_LOOPS,
411 .verify = cppc_verify_policy,
412 .target = cppc_cpufreq_set_target,
413 .get = cppc_cpufreq_get_rate,
414 .init = cppc_cpufreq_cpu_init,
415 .stop_cpu = cppc_cpufreq_stop_cpu,
416 .name = "cppc_cpufreq",
419 static int __init cppc_cpufreq_init(void)
422 struct cppc_cpudata *cpu;
427 all_cpu_data = kcalloc(num_possible_cpus(), sizeof(void *),
432 for_each_possible_cpu(i) {
433 all_cpu_data[i] = kzalloc(sizeof(struct cppc_cpudata), GFP_KERNEL);
434 if (!all_cpu_data[i])
437 cpu = all_cpu_data[i];
438 if (!zalloc_cpumask_var(&cpu->shared_cpu_map, GFP_KERNEL))
442 ret = acpi_get_psd_map(all_cpu_data);
444 pr_debug("Error parsing PSD data. Aborting cpufreq registration.\n");
448 cppc_check_hisi_workaround();
450 ret = cpufreq_register_driver(&cppc_cpufreq_driver);
457 for_each_possible_cpu(i) {
458 cpu = all_cpu_data[i];
461 free_cpumask_var(cpu->shared_cpu_map);
469 static void __exit cppc_cpufreq_exit(void)
471 struct cppc_cpudata *cpu;
474 cpufreq_unregister_driver(&cppc_cpufreq_driver);
476 for_each_possible_cpu(i) {
477 cpu = all_cpu_data[i];
478 free_cpumask_var(cpu->shared_cpu_map);
485 module_exit(cppc_cpufreq_exit);
486 MODULE_AUTHOR("Ashwin Chaugule");
487 MODULE_DESCRIPTION("CPUFreq driver based on the ACPI CPPC v5.0+ spec");
488 MODULE_LICENSE("GPL");
490 late_initcall(cppc_cpufreq_init);
492 static const struct acpi_device_id cppc_acpi_ids[] __used = {
493 {ACPI_PROCESSOR_DEVICE_HID, },
497 MODULE_DEVICE_TABLE(acpi, cppc_acpi_ids);