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
77 /* AVS value for the corresponding voltage (in mV) */
78 static int avs_map[] = {
79 747, 758, 770, 782, 793, 805, 817, 828, 840, 852, 863, 875, 887, 898,
80 910, 922, 933, 945, 957, 968, 980, 992, 1003, 1015, 1027, 1038, 1050,
81 1062, 1073, 1085, 1097, 1108, 1120, 1132, 1143, 1155, 1167, 1178, 1190,
82 1202, 1213, 1225, 1237, 1248, 1260, 1272, 1283, 1295, 1307, 1318, 1330,
86 struct armada37xx_cpufreq_state {
87 struct regmap *regmap;
94 static struct armada37xx_cpufreq_state *armada37xx_cpufreq_state;
96 struct armada_37xx_dvfs {
98 u8 divider[LOAD_LEVEL_NR];
99 u32 avs[LOAD_LEVEL_NR];
102 static struct armada_37xx_dvfs armada_37xx_dvfs[] = {
103 {.cpu_freq_max = 1200*1000*1000, .divider = {1, 2, 4, 6} },
104 {.cpu_freq_max = 1000*1000*1000, .divider = {1, 2, 4, 5} },
105 {.cpu_freq_max = 800*1000*1000, .divider = {1, 2, 3, 4} },
106 {.cpu_freq_max = 600*1000*1000, .divider = {2, 4, 5, 6} },
109 static struct armada_37xx_dvfs *armada_37xx_cpu_freq_info_get(u32 freq)
113 for (i = 0; i < ARRAY_SIZE(armada_37xx_dvfs); i++) {
114 if (freq == armada_37xx_dvfs[i].cpu_freq_max)
115 return &armada_37xx_dvfs[i];
118 pr_err("Unsupported CPU frequency %d MHz\n", freq/1000000);
123 * Setup the four level managed by the hardware. Once the four level
124 * will be configured then the DVFS will be enabled.
126 static void __init armada37xx_cpufreq_dvfs_setup(struct regmap *base,
127 struct regmap *clk_base, u8 *divider)
132 /* Determine to which TBG clock is CPU connected */
133 regmap_read(clk_base, ARMADA_37XX_CLK_TBG_SEL, &cpu_tbg_sel);
134 cpu_tbg_sel >>= ARMADA_37XX_CLK_TBG_SEL_CPU_OFF;
135 cpu_tbg_sel &= ARMADA_37XX_NB_TBG_SEL_MASK;
137 for (load_lvl = 0; load_lvl < LOAD_LEVEL_NR; load_lvl++) {
138 unsigned int reg, mask, val, offset = 0;
140 if (load_lvl <= ARMADA_37XX_DVFS_LOAD_1)
141 reg = ARMADA_37XX_NB_L0L1;
143 reg = ARMADA_37XX_NB_L2L3;
145 if (load_lvl == ARMADA_37XX_DVFS_LOAD_0 ||
146 load_lvl == ARMADA_37XX_DVFS_LOAD_2)
147 offset += ARMADA_37XX_NB_CONFIG_SHIFT;
149 /* Set cpu clock source, for all the level we use TBG */
150 val = ARMADA_37XX_NB_CLK_SEL_TBG << ARMADA_37XX_NB_CLK_SEL_OFF;
151 mask = (ARMADA_37XX_NB_CLK_SEL_MASK
152 << ARMADA_37XX_NB_CLK_SEL_OFF);
154 /* Set TBG index, for all levels we use the same TBG */
155 val = cpu_tbg_sel << ARMADA_37XX_NB_TBG_SEL_OFF;
156 mask = (ARMADA_37XX_NB_TBG_SEL_MASK
157 << ARMADA_37XX_NB_TBG_SEL_OFF);
160 * Set cpu divider based on the pre-computed array in
161 * order to have balanced step.
163 val |= divider[load_lvl] << ARMADA_37XX_NB_TBG_DIV_OFF;
164 mask |= (ARMADA_37XX_NB_TBG_DIV_MASK
165 << ARMADA_37XX_NB_TBG_DIV_OFF);
167 /* Set VDD divider which is actually the load level. */
168 val |= load_lvl << ARMADA_37XX_NB_VDD_SEL_OFF;
169 mask |= (ARMADA_37XX_NB_VDD_SEL_MASK
170 << ARMADA_37XX_NB_VDD_SEL_OFF);
175 regmap_update_bits(base, reg, mask, val);
180 * Find out the armada 37x supported AVS value whose voltage value is
181 * the round-up closest to the target voltage value.
183 static u32 armada_37xx_avs_val_match(int target_vm)
187 /* Find out the round-up closest supported voltage value */
188 for (avs = 0; avs < ARRAY_SIZE(avs_map); avs++)
189 if (avs_map[avs] >= target_vm)
193 * If all supported voltages are smaller than target one,
194 * choose the largest supported voltage
196 if (avs == ARRAY_SIZE(avs_map))
197 avs = ARRAY_SIZE(avs_map) - 1;
203 * For Armada 37xx soc, L0(VSET0) VDD AVS value is set to SVC revision
204 * value or a default value when SVC is not supported.
205 * - L0 can be read out from the register of AVS_CTRL_0 and L0 voltage
206 * can be got from the mapping table of avs_map.
207 * - L1 voltage should be about 100mv smaller than L0 voltage
208 * - L2 & L3 voltage should be about 150mv smaller than L0 voltage.
209 * This function calculates L1 & L2 & L3 AVS values dynamically based
210 * on L0 voltage and fill all AVS values to the AVS value table.
212 static void __init armada37xx_cpufreq_avs_configure(struct regmap *base,
213 struct armada_37xx_dvfs *dvfs)
215 unsigned int target_vm;
222 /* Get L0 VDD min value */
223 regmap_read(base, ARMADA_37XX_AVS_CTL0, &l0_vdd_min);
224 l0_vdd_min = (l0_vdd_min >> ARMADA_37XX_AVS_LOW_VDD_LIMIT) &
225 ARMADA_37XX_AVS_VDD_MASK;
226 if (l0_vdd_min >= ARRAY_SIZE(avs_map)) {
227 pr_err("L0 VDD MIN %d is not correct.\n", l0_vdd_min);
230 dvfs->avs[0] = l0_vdd_min;
232 if (avs_map[l0_vdd_min] <= MIN_VOLT_MV) {
234 * If L0 voltage is smaller than 1000mv, then all VDD sets
237 u32 avs_min = armada_37xx_avs_val_match(MIN_VOLT_MV);
239 for (load_level = 1; load_level < LOAD_LEVEL_NR; load_level++)
240 dvfs->avs[load_level] = avs_min;
246 * L1 voltage is equal to L0 voltage - 100mv and it must be
250 target_vm = avs_map[l0_vdd_min] - 100;
251 target_vm = target_vm > MIN_VOLT_MV ? target_vm : MIN_VOLT_MV;
252 dvfs->avs[1] = armada_37xx_avs_val_match(target_vm);
255 * L2 & L3 voltage is equal to L0 voltage - 150mv and it must
256 * be larger than 1000mv
258 target_vm = avs_map[l0_vdd_min] - 150;
259 target_vm = target_vm > MIN_VOLT_MV ? target_vm : MIN_VOLT_MV;
260 dvfs->avs[2] = dvfs->avs[3] = armada_37xx_avs_val_match(target_vm);
263 static void __init armada37xx_cpufreq_avs_setup(struct regmap *base,
264 struct armada_37xx_dvfs *dvfs)
266 unsigned int avs_val = 0;
272 /* Disable AVS before the configuration */
273 regmap_update_bits(base, ARMADA_37XX_AVS_CTL0,
274 ARMADA_37XX_AVS_ENABLE, 0);
277 /* Enable low voltage mode */
278 regmap_update_bits(base, ARMADA_37XX_AVS_CTL2,
279 ARMADA_37XX_AVS_LOW_VDD_EN,
280 ARMADA_37XX_AVS_LOW_VDD_EN);
283 for (load_level = 1; load_level < LOAD_LEVEL_NR; load_level++) {
284 avs_val = dvfs->avs[load_level];
285 regmap_update_bits(base, ARMADA_37XX_AVS_VSET(load_level-1),
286 ARMADA_37XX_AVS_VDD_MASK << ARMADA_37XX_AVS_HIGH_VDD_LIMIT |
287 ARMADA_37XX_AVS_VDD_MASK << ARMADA_37XX_AVS_LOW_VDD_LIMIT,
288 avs_val << ARMADA_37XX_AVS_HIGH_VDD_LIMIT |
289 avs_val << ARMADA_37XX_AVS_LOW_VDD_LIMIT);
292 /* Enable AVS after the configuration */
293 regmap_update_bits(base, ARMADA_37XX_AVS_CTL0,
294 ARMADA_37XX_AVS_ENABLE,
295 ARMADA_37XX_AVS_ENABLE);
299 static void armada37xx_cpufreq_disable_dvfs(struct regmap *base)
301 unsigned int reg = ARMADA_37XX_NB_DYN_MOD,
302 mask = ARMADA_37XX_NB_DFS_EN;
304 regmap_update_bits(base, reg, mask, 0);
307 static void __init armada37xx_cpufreq_enable_dvfs(struct regmap *base)
309 unsigned int val, reg = ARMADA_37XX_NB_CPU_LOAD,
310 mask = ARMADA_37XX_NB_CPU_LOAD_MASK;
312 /* Start with the highest load (0) */
313 val = ARMADA_37XX_DVFS_LOAD_0;
314 regmap_update_bits(base, reg, mask, val);
316 /* Now enable DVFS for the CPUs */
317 reg = ARMADA_37XX_NB_DYN_MOD;
318 mask = ARMADA_37XX_NB_CLK_SEL_EN | ARMADA_37XX_NB_TBG_EN |
319 ARMADA_37XX_NB_DIV_EN | ARMADA_37XX_NB_VDD_EN |
320 ARMADA_37XX_NB_DFS_EN;
322 regmap_update_bits(base, reg, mask, mask);
325 static int armada37xx_cpufreq_suspend(struct cpufreq_policy *policy)
327 struct armada37xx_cpufreq_state *state = armada37xx_cpufreq_state;
329 regmap_read(state->regmap, ARMADA_37XX_NB_L0L1, &state->nb_l0l1);
330 regmap_read(state->regmap, ARMADA_37XX_NB_L2L3, &state->nb_l2l3);
331 regmap_read(state->regmap, ARMADA_37XX_NB_CPU_LOAD,
332 &state->nb_cpu_load);
333 regmap_read(state->regmap, ARMADA_37XX_NB_DYN_MOD, &state->nb_dyn_mod);
338 static int armada37xx_cpufreq_resume(struct cpufreq_policy *policy)
340 struct armada37xx_cpufreq_state *state = armada37xx_cpufreq_state;
342 /* Ensure DVFS is disabled otherwise the following registers are RO */
343 armada37xx_cpufreq_disable_dvfs(state->regmap);
345 regmap_write(state->regmap, ARMADA_37XX_NB_L0L1, state->nb_l0l1);
346 regmap_write(state->regmap, ARMADA_37XX_NB_L2L3, state->nb_l2l3);
347 regmap_write(state->regmap, ARMADA_37XX_NB_CPU_LOAD,
351 * NB_DYN_MOD register is the one that actually enable back DVFS if it
352 * was enabled before the suspend operation. This must be done last
353 * otherwise other registers are not writable.
355 regmap_write(state->regmap, ARMADA_37XX_NB_DYN_MOD, state->nb_dyn_mod);
360 static int __init armada37xx_cpufreq_driver_init(void)
362 struct cpufreq_dt_platform_data pdata;
363 struct armada_37xx_dvfs *dvfs;
364 struct platform_device *pdev;
366 unsigned int cur_frequency, base_frequency;
367 struct regmap *nb_clk_base, *nb_pm_base, *avs_base;
368 struct device *cpu_dev;
370 struct clk *clk, *parent;
373 syscon_regmap_lookup_by_compatible("marvell,armada-3700-periph-clock-nb");
374 if (IS_ERR(nb_clk_base))
378 syscon_regmap_lookup_by_compatible("marvell,armada-3700-nb-pm");
380 if (IS_ERR(nb_pm_base))
384 syscon_regmap_lookup_by_compatible("marvell,armada-3700-avs");
386 /* if AVS is not present don't use it but still try to setup dvfs */
387 if (IS_ERR(avs_base)) {
388 pr_info("Syscon failed for Adapting Voltage Scaling: skip it\n");
391 /* Before doing any configuration on the DVFS first, disable it */
392 armada37xx_cpufreq_disable_dvfs(nb_pm_base);
395 * On CPU 0 register the operating points supported (which are
396 * the nominal CPU frequency and full integer divisions of
399 cpu_dev = get_cpu_device(0);
401 dev_err(cpu_dev, "Cannot get CPU\n");
405 clk = clk_get(cpu_dev, 0);
407 dev_err(cpu_dev, "Cannot get clock for CPU0\n");
411 parent = clk_get_parent(clk);
412 if (IS_ERR(parent)) {
413 dev_err(cpu_dev, "Cannot get parent clock for CPU0\n");
415 return PTR_ERR(parent);
418 /* Get parent CPU frequency */
419 base_frequency = clk_get_rate(parent);
421 if (!base_frequency) {
422 dev_err(cpu_dev, "Failed to get parent clock rate for CPU\n");
427 /* Get nominal (current) CPU frequency */
428 cur_frequency = clk_get_rate(clk);
429 if (!cur_frequency) {
430 dev_err(cpu_dev, "Failed to get clock rate for CPU\n");
435 dvfs = armada_37xx_cpu_freq_info_get(cur_frequency);
441 armada37xx_cpufreq_state = kmalloc(sizeof(*armada37xx_cpufreq_state),
443 if (!armada37xx_cpufreq_state) {
448 armada37xx_cpufreq_state->regmap = nb_pm_base;
450 armada37xx_cpufreq_avs_configure(avs_base, dvfs);
451 armada37xx_cpufreq_avs_setup(avs_base, dvfs);
453 armada37xx_cpufreq_dvfs_setup(nb_pm_base, nb_clk_base, dvfs->divider);
456 for (load_lvl = ARMADA_37XX_DVFS_LOAD_0; load_lvl < LOAD_LEVEL_NR;
458 unsigned long u_volt = avs_map[dvfs->avs[load_lvl]] * 1000;
459 freq = base_frequency / dvfs->divider[load_lvl];
460 ret = dev_pm_opp_add(cpu_dev, freq, u_volt);
467 /* Now that everything is setup, enable the DVFS at hardware level */
468 armada37xx_cpufreq_enable_dvfs(nb_pm_base);
470 memset(&pdata, 0, sizeof(pdata));
471 pdata.suspend = armada37xx_cpufreq_suspend;
472 pdata.resume = armada37xx_cpufreq_resume;
474 pdev = platform_device_register_data(NULL, "cpufreq-dt", -1, &pdata,
476 ret = PTR_ERR_OR_ZERO(pdev);
483 armada37xx_cpufreq_disable_dvfs(nb_pm_base);
485 /* clean-up the already added opp before leaving */
486 while (load_lvl-- > ARMADA_37XX_DVFS_LOAD_0) {
487 freq = cur_frequency / dvfs->divider[load_lvl];
488 dev_pm_opp_remove(cpu_dev, freq);
491 kfree(armada37xx_cpufreq_state);
495 /* late_initcall, to guarantee the driver is loaded after A37xx clock driver */
496 late_initcall(armada37xx_cpufreq_driver_init);
498 static const struct of_device_id __maybe_unused armada37xx_cpufreq_of_match[] = {
499 { .compatible = "marvell,armada-3700-nb-pm" },
502 MODULE_DEVICE_TABLE(of, armada37xx_cpufreq_of_match);
504 MODULE_AUTHOR("Gregory CLEMENT <gregory.clement@free-electrons.com>");
505 MODULE_DESCRIPTION("Armada 37xx cpufreq driver");
506 MODULE_LICENSE("GPL");