1 // SPDX-License-Identifier: GPL-2.0+
3 * CPU frequency scaling support for Armada 37xx platform.
5 * Copyright (C) 2017 Marvell
7 * Gregory CLEMENT <gregory.clement@free-electrons.com>
10 #include <linux/clk.h>
11 #include <linux/cpu.h>
12 #include <linux/cpufreq.h>
13 #include <linux/err.h>
14 #include <linux/interrupt.h>
16 #include <linux/mfd/syscon.h>
17 #include <linux/module.h>
18 #include <linux/of_address.h>
19 #include <linux/of_device.h>
20 #include <linux/of_irq.h>
21 #include <linux/platform_device.h>
22 #include <linux/pm_opp.h>
23 #include <linux/regmap.h>
24 #include <linux/slab.h>
26 #include "cpufreq-dt.h"
28 /* Clk register set */
29 #define ARMADA_37XX_CLK_TBG_SEL 0
30 #define ARMADA_37XX_CLK_TBG_SEL_CPU_OFF 22
32 /* Power management in North Bridge register set */
33 #define ARMADA_37XX_NB_L0L1 0x18
34 #define ARMADA_37XX_NB_L2L3 0x1C
35 #define ARMADA_37XX_NB_TBG_DIV_OFF 13
36 #define ARMADA_37XX_NB_TBG_DIV_MASK 0x7
37 #define ARMADA_37XX_NB_CLK_SEL_OFF 11
38 #define ARMADA_37XX_NB_CLK_SEL_MASK 0x1
39 #define ARMADA_37XX_NB_CLK_SEL_TBG 0x1
40 #define ARMADA_37XX_NB_TBG_SEL_OFF 9
41 #define ARMADA_37XX_NB_TBG_SEL_MASK 0x3
42 #define ARMADA_37XX_NB_VDD_SEL_OFF 6
43 #define ARMADA_37XX_NB_VDD_SEL_MASK 0x3
44 #define ARMADA_37XX_NB_CONFIG_SHIFT 16
45 #define ARMADA_37XX_NB_DYN_MOD 0x24
46 #define ARMADA_37XX_NB_CLK_SEL_EN BIT(26)
47 #define ARMADA_37XX_NB_TBG_EN BIT(28)
48 #define ARMADA_37XX_NB_DIV_EN BIT(29)
49 #define ARMADA_37XX_NB_VDD_EN BIT(30)
50 #define ARMADA_37XX_NB_DFS_EN BIT(31)
51 #define ARMADA_37XX_NB_CPU_LOAD 0x30
52 #define ARMADA_37XX_NB_CPU_LOAD_MASK 0x3
53 #define ARMADA_37XX_DVFS_LOAD_0 0
54 #define ARMADA_37XX_DVFS_LOAD_1 1
55 #define ARMADA_37XX_DVFS_LOAD_2 2
56 #define ARMADA_37XX_DVFS_LOAD_3 3
58 /* AVS register set */
59 #define ARMADA_37XX_AVS_CTL0 0x0
60 #define ARMADA_37XX_AVS_ENABLE BIT(30)
61 #define ARMADA_37XX_AVS_HIGH_VDD_LIMIT 16
62 #define ARMADA_37XX_AVS_LOW_VDD_LIMIT 22
63 #define ARMADA_37XX_AVS_VDD_MASK 0x3F
64 #define ARMADA_37XX_AVS_CTL2 0x8
65 #define ARMADA_37XX_AVS_LOW_VDD_EN BIT(6)
66 #define ARMADA_37XX_AVS_VSET(x) (0x1C + 4 * (x))
69 * On Armada 37xx the Power management manages 4 level of CPU load,
70 * each level can be associated with a CPU clock source, a CPU
71 * divider, a VDD level, etc...
73 #define LOAD_LEVEL_NR 4
75 #define MIN_VOLT_MV 1000
76 #define MIN_VOLT_MV_FOR_L1_1000MHZ 1108
77 #define MIN_VOLT_MV_FOR_L1_1200MHZ 1155
79 /* AVS value for the corresponding voltage (in mV) */
80 static int avs_map[] = {
81 747, 758, 770, 782, 793, 805, 817, 828, 840, 852, 863, 875, 887, 898,
82 910, 922, 933, 945, 957, 968, 980, 992, 1003, 1015, 1027, 1038, 1050,
83 1062, 1073, 1085, 1097, 1108, 1120, 1132, 1143, 1155, 1167, 1178, 1190,
84 1202, 1213, 1225, 1237, 1248, 1260, 1272, 1283, 1295, 1307, 1318, 1330,
88 struct armada37xx_cpufreq_state {
89 struct regmap *regmap;
96 static struct armada37xx_cpufreq_state *armada37xx_cpufreq_state;
98 struct armada_37xx_dvfs {
100 u8 divider[LOAD_LEVEL_NR];
101 u32 avs[LOAD_LEVEL_NR];
104 static struct armada_37xx_dvfs armada_37xx_dvfs[] = {
105 {.cpu_freq_max = 1200*1000*1000, .divider = {1, 2, 4, 6} },
106 {.cpu_freq_max = 1000*1000*1000, .divider = {1, 2, 4, 5} },
107 {.cpu_freq_max = 800*1000*1000, .divider = {1, 2, 3, 4} },
108 {.cpu_freq_max = 600*1000*1000, .divider = {2, 4, 5, 6} },
111 static struct armada_37xx_dvfs *armada_37xx_cpu_freq_info_get(u32 freq)
115 for (i = 0; i < ARRAY_SIZE(armada_37xx_dvfs); i++) {
116 if (freq == armada_37xx_dvfs[i].cpu_freq_max)
117 return &armada_37xx_dvfs[i];
120 pr_err("Unsupported CPU frequency %d MHz\n", freq/1000000);
125 * Setup the four level managed by the hardware. Once the four level
126 * will be configured then the DVFS will be enabled.
128 static void __init armada37xx_cpufreq_dvfs_setup(struct regmap *base,
129 struct regmap *clk_base, u8 *divider)
134 /* Determine to which TBG clock is CPU connected */
135 regmap_read(clk_base, ARMADA_37XX_CLK_TBG_SEL, &cpu_tbg_sel);
136 cpu_tbg_sel >>= ARMADA_37XX_CLK_TBG_SEL_CPU_OFF;
137 cpu_tbg_sel &= ARMADA_37XX_NB_TBG_SEL_MASK;
139 for (load_lvl = 0; load_lvl < LOAD_LEVEL_NR; load_lvl++) {
140 unsigned int reg, mask, val, offset = 0;
142 if (load_lvl <= ARMADA_37XX_DVFS_LOAD_1)
143 reg = ARMADA_37XX_NB_L0L1;
145 reg = ARMADA_37XX_NB_L2L3;
147 if (load_lvl == ARMADA_37XX_DVFS_LOAD_0 ||
148 load_lvl == ARMADA_37XX_DVFS_LOAD_2)
149 offset += ARMADA_37XX_NB_CONFIG_SHIFT;
151 /* Set cpu clock source, for all the level we use TBG */
152 val = ARMADA_37XX_NB_CLK_SEL_TBG << ARMADA_37XX_NB_CLK_SEL_OFF;
153 mask = (ARMADA_37XX_NB_CLK_SEL_MASK
154 << ARMADA_37XX_NB_CLK_SEL_OFF);
156 /* Set TBG index, for all levels we use the same TBG */
157 val = cpu_tbg_sel << ARMADA_37XX_NB_TBG_SEL_OFF;
158 mask = (ARMADA_37XX_NB_TBG_SEL_MASK
159 << ARMADA_37XX_NB_TBG_SEL_OFF);
162 * Set cpu divider based on the pre-computed array in
163 * order to have balanced step.
165 val |= divider[load_lvl] << ARMADA_37XX_NB_TBG_DIV_OFF;
166 mask |= (ARMADA_37XX_NB_TBG_DIV_MASK
167 << ARMADA_37XX_NB_TBG_DIV_OFF);
169 /* Set VDD divider which is actually the load level. */
170 val |= load_lvl << ARMADA_37XX_NB_VDD_SEL_OFF;
171 mask |= (ARMADA_37XX_NB_VDD_SEL_MASK
172 << ARMADA_37XX_NB_VDD_SEL_OFF);
177 regmap_update_bits(base, reg, mask, val);
182 * Find out the armada 37x supported AVS value whose voltage value is
183 * the round-up closest to the target voltage value.
185 static u32 armada_37xx_avs_val_match(int target_vm)
189 /* Find out the round-up closest supported voltage value */
190 for (avs = 0; avs < ARRAY_SIZE(avs_map); avs++)
191 if (avs_map[avs] >= target_vm)
195 * If all supported voltages are smaller than target one,
196 * choose the largest supported voltage
198 if (avs == ARRAY_SIZE(avs_map))
199 avs = ARRAY_SIZE(avs_map) - 1;
205 * For Armada 37xx soc, L0(VSET0) VDD AVS value is set to SVC revision
206 * value or a default value when SVC is not supported.
207 * - L0 can be read out from the register of AVS_CTRL_0 and L0 voltage
208 * can be got from the mapping table of avs_map.
209 * - L1 voltage should be about 100mv smaller than L0 voltage
210 * - L2 & L3 voltage should be about 150mv smaller than L0 voltage.
211 * This function calculates L1 & L2 & L3 AVS values dynamically based
212 * on L0 voltage and fill all AVS values to the AVS value table.
213 * When base CPU frequency is 1000 or 1200 MHz then there is additional
214 * minimal avs value for load L1.
216 static void __init armada37xx_cpufreq_avs_configure(struct regmap *base,
217 struct armada_37xx_dvfs *dvfs)
219 unsigned int target_vm;
226 /* Get L0 VDD min value */
227 regmap_read(base, ARMADA_37XX_AVS_CTL0, &l0_vdd_min);
228 l0_vdd_min = (l0_vdd_min >> ARMADA_37XX_AVS_LOW_VDD_LIMIT) &
229 ARMADA_37XX_AVS_VDD_MASK;
230 if (l0_vdd_min >= ARRAY_SIZE(avs_map)) {
231 pr_err("L0 VDD MIN %d is not correct.\n", l0_vdd_min);
234 dvfs->avs[0] = l0_vdd_min;
236 if (avs_map[l0_vdd_min] <= MIN_VOLT_MV) {
238 * If L0 voltage is smaller than 1000mv, then all VDD sets
241 u32 avs_min = armada_37xx_avs_val_match(MIN_VOLT_MV);
243 for (load_level = 1; load_level < LOAD_LEVEL_NR; load_level++)
244 dvfs->avs[load_level] = avs_min;
247 * Set the avs values for load L0 and L1 when base CPU frequency
248 * is 1000/1200 MHz to its typical initial values according to
249 * the Armada 3700 Hardware Specifications.
251 if (dvfs->cpu_freq_max >= 1000*1000*1000) {
252 if (dvfs->cpu_freq_max >= 1200*1000*1000)
253 avs_min = armada_37xx_avs_val_match(MIN_VOLT_MV_FOR_L1_1200MHZ);
255 avs_min = armada_37xx_avs_val_match(MIN_VOLT_MV_FOR_L1_1000MHZ);
256 dvfs->avs[0] = dvfs->avs[1] = avs_min;
263 * L1 voltage is equal to L0 voltage - 100mv and it must be
267 target_vm = avs_map[l0_vdd_min] - 100;
268 target_vm = target_vm > MIN_VOLT_MV ? target_vm : MIN_VOLT_MV;
269 dvfs->avs[1] = armada_37xx_avs_val_match(target_vm);
272 * L2 & L3 voltage is equal to L0 voltage - 150mv and it must
273 * be larger than 1000mv
275 target_vm = avs_map[l0_vdd_min] - 150;
276 target_vm = target_vm > MIN_VOLT_MV ? target_vm : MIN_VOLT_MV;
277 dvfs->avs[2] = dvfs->avs[3] = armada_37xx_avs_val_match(target_vm);
280 * Fix the avs value for load L1 when base CPU frequency is 1000/1200 MHz,
281 * otherwise the CPU gets stuck when switching from load L1 to load L0.
282 * Also ensure that avs value for load L1 is not higher than for L0.
284 if (dvfs->cpu_freq_max >= 1000*1000*1000) {
287 if (dvfs->cpu_freq_max >= 1200*1000*1000)
288 avs_min_l1 = armada_37xx_avs_val_match(MIN_VOLT_MV_FOR_L1_1200MHZ);
290 avs_min_l1 = armada_37xx_avs_val_match(MIN_VOLT_MV_FOR_L1_1000MHZ);
292 if (avs_min_l1 > dvfs->avs[0])
293 avs_min_l1 = dvfs->avs[0];
295 if (dvfs->avs[1] < avs_min_l1)
296 dvfs->avs[1] = avs_min_l1;
300 static void __init armada37xx_cpufreq_avs_setup(struct regmap *base,
301 struct armada_37xx_dvfs *dvfs)
303 unsigned int avs_val = 0;
309 /* Disable AVS before the configuration */
310 regmap_update_bits(base, ARMADA_37XX_AVS_CTL0,
311 ARMADA_37XX_AVS_ENABLE, 0);
314 /* Enable low voltage mode */
315 regmap_update_bits(base, ARMADA_37XX_AVS_CTL2,
316 ARMADA_37XX_AVS_LOW_VDD_EN,
317 ARMADA_37XX_AVS_LOW_VDD_EN);
320 for (load_level = 1; load_level < LOAD_LEVEL_NR; load_level++) {
321 avs_val = dvfs->avs[load_level];
322 regmap_update_bits(base, ARMADA_37XX_AVS_VSET(load_level-1),
323 ARMADA_37XX_AVS_VDD_MASK << ARMADA_37XX_AVS_HIGH_VDD_LIMIT |
324 ARMADA_37XX_AVS_VDD_MASK << ARMADA_37XX_AVS_LOW_VDD_LIMIT,
325 avs_val << ARMADA_37XX_AVS_HIGH_VDD_LIMIT |
326 avs_val << ARMADA_37XX_AVS_LOW_VDD_LIMIT);
329 /* Enable AVS after the configuration */
330 regmap_update_bits(base, ARMADA_37XX_AVS_CTL0,
331 ARMADA_37XX_AVS_ENABLE,
332 ARMADA_37XX_AVS_ENABLE);
336 static void armada37xx_cpufreq_disable_dvfs(struct regmap *base)
338 unsigned int reg = ARMADA_37XX_NB_DYN_MOD,
339 mask = ARMADA_37XX_NB_DFS_EN;
341 regmap_update_bits(base, reg, mask, 0);
344 static void __init armada37xx_cpufreq_enable_dvfs(struct regmap *base)
346 unsigned int val, reg = ARMADA_37XX_NB_CPU_LOAD,
347 mask = ARMADA_37XX_NB_CPU_LOAD_MASK;
349 /* Start with the highest load (0) */
350 val = ARMADA_37XX_DVFS_LOAD_0;
351 regmap_update_bits(base, reg, mask, val);
353 /* Now enable DVFS for the CPUs */
354 reg = ARMADA_37XX_NB_DYN_MOD;
355 mask = ARMADA_37XX_NB_CLK_SEL_EN | ARMADA_37XX_NB_TBG_EN |
356 ARMADA_37XX_NB_DIV_EN | ARMADA_37XX_NB_VDD_EN |
357 ARMADA_37XX_NB_DFS_EN;
359 regmap_update_bits(base, reg, mask, mask);
362 static int armada37xx_cpufreq_suspend(struct cpufreq_policy *policy)
364 struct armada37xx_cpufreq_state *state = armada37xx_cpufreq_state;
366 regmap_read(state->regmap, ARMADA_37XX_NB_L0L1, &state->nb_l0l1);
367 regmap_read(state->regmap, ARMADA_37XX_NB_L2L3, &state->nb_l2l3);
368 regmap_read(state->regmap, ARMADA_37XX_NB_CPU_LOAD,
369 &state->nb_cpu_load);
370 regmap_read(state->regmap, ARMADA_37XX_NB_DYN_MOD, &state->nb_dyn_mod);
375 static int armada37xx_cpufreq_resume(struct cpufreq_policy *policy)
377 struct armada37xx_cpufreq_state *state = armada37xx_cpufreq_state;
379 /* Ensure DVFS is disabled otherwise the following registers are RO */
380 armada37xx_cpufreq_disable_dvfs(state->regmap);
382 regmap_write(state->regmap, ARMADA_37XX_NB_L0L1, state->nb_l0l1);
383 regmap_write(state->regmap, ARMADA_37XX_NB_L2L3, state->nb_l2l3);
384 regmap_write(state->regmap, ARMADA_37XX_NB_CPU_LOAD,
388 * NB_DYN_MOD register is the one that actually enable back DVFS if it
389 * was enabled before the suspend operation. This must be done last
390 * otherwise other registers are not writable.
392 regmap_write(state->regmap, ARMADA_37XX_NB_DYN_MOD, state->nb_dyn_mod);
397 static int __init armada37xx_cpufreq_driver_init(void)
399 struct cpufreq_dt_platform_data pdata;
400 struct armada_37xx_dvfs *dvfs;
401 struct platform_device *pdev;
403 unsigned int cur_frequency, base_frequency;
404 struct regmap *nb_clk_base, *nb_pm_base, *avs_base;
405 struct device *cpu_dev;
407 struct clk *clk, *parent;
410 syscon_regmap_lookup_by_compatible("marvell,armada-3700-periph-clock-nb");
411 if (IS_ERR(nb_clk_base))
415 syscon_regmap_lookup_by_compatible("marvell,armada-3700-nb-pm");
417 if (IS_ERR(nb_pm_base))
421 syscon_regmap_lookup_by_compatible("marvell,armada-3700-avs");
423 /* if AVS is not present don't use it but still try to setup dvfs */
424 if (IS_ERR(avs_base)) {
425 pr_info("Syscon failed for Adapting Voltage Scaling: skip it\n");
428 /* Before doing any configuration on the DVFS first, disable it */
429 armada37xx_cpufreq_disable_dvfs(nb_pm_base);
432 * On CPU 0 register the operating points supported (which are
433 * the nominal CPU frequency and full integer divisions of
436 cpu_dev = get_cpu_device(0);
438 dev_err(cpu_dev, "Cannot get CPU\n");
442 clk = clk_get(cpu_dev, 0);
444 dev_err(cpu_dev, "Cannot get clock for CPU0\n");
448 parent = clk_get_parent(clk);
449 if (IS_ERR(parent)) {
450 dev_err(cpu_dev, "Cannot get parent clock for CPU0\n");
452 return PTR_ERR(parent);
455 /* Get parent CPU frequency */
456 base_frequency = clk_get_rate(parent);
458 if (!base_frequency) {
459 dev_err(cpu_dev, "Failed to get parent clock rate for CPU\n");
464 /* Get nominal (current) CPU frequency */
465 cur_frequency = clk_get_rate(clk);
466 if (!cur_frequency) {
467 dev_err(cpu_dev, "Failed to get clock rate for CPU\n");
472 dvfs = armada_37xx_cpu_freq_info_get(cur_frequency);
478 armada37xx_cpufreq_state = kmalloc(sizeof(*armada37xx_cpufreq_state),
480 if (!armada37xx_cpufreq_state) {
485 armada37xx_cpufreq_state->regmap = nb_pm_base;
487 armada37xx_cpufreq_avs_configure(avs_base, dvfs);
488 armada37xx_cpufreq_avs_setup(avs_base, dvfs);
490 armada37xx_cpufreq_dvfs_setup(nb_pm_base, nb_clk_base, dvfs->divider);
493 for (load_lvl = ARMADA_37XX_DVFS_LOAD_0; load_lvl < LOAD_LEVEL_NR;
495 unsigned long u_volt = avs_map[dvfs->avs[load_lvl]] * 1000;
496 freq = base_frequency / dvfs->divider[load_lvl];
497 ret = dev_pm_opp_add(cpu_dev, freq, u_volt);
504 /* Now that everything is setup, enable the DVFS at hardware level */
505 armada37xx_cpufreq_enable_dvfs(nb_pm_base);
507 memset(&pdata, 0, sizeof(pdata));
508 pdata.suspend = armada37xx_cpufreq_suspend;
509 pdata.resume = armada37xx_cpufreq_resume;
511 pdev = platform_device_register_data(NULL, "cpufreq-dt", -1, &pdata,
513 ret = PTR_ERR_OR_ZERO(pdev);
520 armada37xx_cpufreq_disable_dvfs(nb_pm_base);
522 /* clean-up the already added opp before leaving */
523 while (load_lvl-- > ARMADA_37XX_DVFS_LOAD_0) {
524 freq = cur_frequency / dvfs->divider[load_lvl];
525 dev_pm_opp_remove(cpu_dev, freq);
528 kfree(armada37xx_cpufreq_state);
532 /* late_initcall, to guarantee the driver is loaded after A37xx clock driver */
533 late_initcall(armada37xx_cpufreq_driver_init);
535 static const struct of_device_id __maybe_unused armada37xx_cpufreq_of_match[] = {
536 { .compatible = "marvell,armada-3700-nb-pm" },
539 MODULE_DEVICE_TABLE(of, armada37xx_cpufreq_of_match);
541 MODULE_AUTHOR("Gregory CLEMENT <gregory.clement@free-electrons.com>");
542 MODULE_DESCRIPTION("Armada 37xx cpufreq driver");
543 MODULE_LICENSE("GPL");