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1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * CPU frequency scaling support for Armada 37xx platform.
4 *
5 * Copyright (C) 2017 Marvell
6 *
7 * Gregory CLEMENT <gregory.clement@free-electrons.com>
8 */
9
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>
15#include <linux/io.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>
25
26#include "cpufreq-dt.h"
27
28/* Power management in North Bridge register set */
29#define ARMADA_37XX_NB_L0L1 0x18
30#define ARMADA_37XX_NB_L2L3 0x1C
31#define ARMADA_37XX_NB_TBG_DIV_OFF 13
32#define ARMADA_37XX_NB_TBG_DIV_MASK 0x7
33#define ARMADA_37XX_NB_CLK_SEL_OFF 11
34#define ARMADA_37XX_NB_CLK_SEL_MASK 0x1
35#define ARMADA_37XX_NB_CLK_SEL_TBG 0x1
36#define ARMADA_37XX_NB_TBG_SEL_OFF 9
37#define ARMADA_37XX_NB_TBG_SEL_MASK 0x3
38#define ARMADA_37XX_NB_VDD_SEL_OFF 6
39#define ARMADA_37XX_NB_VDD_SEL_MASK 0x3
40#define ARMADA_37XX_NB_CONFIG_SHIFT 16
41#define ARMADA_37XX_NB_DYN_MOD 0x24
42#define ARMADA_37XX_NB_CLK_SEL_EN BIT(26)
43#define ARMADA_37XX_NB_TBG_EN BIT(28)
44#define ARMADA_37XX_NB_DIV_EN BIT(29)
45#define ARMADA_37XX_NB_VDD_EN BIT(30)
46#define ARMADA_37XX_NB_DFS_EN BIT(31)
47#define ARMADA_37XX_NB_CPU_LOAD 0x30
48#define ARMADA_37XX_NB_CPU_LOAD_MASK 0x3
49#define ARMADA_37XX_DVFS_LOAD_0 0
50#define ARMADA_37XX_DVFS_LOAD_1 1
51#define ARMADA_37XX_DVFS_LOAD_2 2
52#define ARMADA_37XX_DVFS_LOAD_3 3
53
54/* AVS register set */
55#define ARMADA_37XX_AVS_CTL0 0x0
56#define ARMADA_37XX_AVS_ENABLE BIT(30)
57#define ARMADA_37XX_AVS_HIGH_VDD_LIMIT 16
58#define ARMADA_37XX_AVS_LOW_VDD_LIMIT 22
59#define ARMADA_37XX_AVS_VDD_MASK 0x3F
60#define ARMADA_37XX_AVS_CTL2 0x8
61#define ARMADA_37XX_AVS_LOW_VDD_EN BIT(6)
62#define ARMADA_37XX_AVS_VSET(x) (0x1C + 4 * (x))
63
64/*
65 * On Armada 37xx the Power management manages 4 level of CPU load,
66 * each level can be associated with a CPU clock source, a CPU
67 * divider, a VDD level, etc...
68 */
69#define LOAD_LEVEL_NR 4
70
71#define MIN_VOLT_MV 1000
72
73/* AVS value for the corresponding voltage (in mV) */
74static int avs_map[] = {
75 747, 758, 770, 782, 793, 805, 817, 828, 840, 852, 863, 875, 887, 898,
76 910, 922, 933, 945, 957, 968, 980, 992, 1003, 1015, 1027, 1038, 1050,
77 1062, 1073, 1085, 1097, 1108, 1120, 1132, 1143, 1155, 1167, 1178, 1190,
78 1202, 1213, 1225, 1237, 1248, 1260, 1272, 1283, 1295, 1307, 1318, 1330,
79 1342
80};
81
82struct armada37xx_cpufreq_state {
83 struct regmap *regmap;
84 u32 nb_l0l1;
85 u32 nb_l2l3;
86 u32 nb_dyn_mod;
87 u32 nb_cpu_load;
88};
89
90static struct armada37xx_cpufreq_state *armada37xx_cpufreq_state;
91
92struct armada_37xx_dvfs {
93 u32 cpu_freq_max;
94 u8 divider[LOAD_LEVEL_NR];
95 u32 avs[LOAD_LEVEL_NR];
96};
97
98static struct armada_37xx_dvfs armada_37xx_dvfs[] = {
99 {.cpu_freq_max = 1200*1000*1000, .divider = {1, 2, 4, 6} },
100 {.cpu_freq_max = 1000*1000*1000, .divider = {1, 2, 4, 5} },
101 {.cpu_freq_max = 800*1000*1000, .divider = {1, 2, 3, 4} },
102 {.cpu_freq_max = 600*1000*1000, .divider = {2, 4, 5, 6} },
103};
104
105static struct armada_37xx_dvfs *armada_37xx_cpu_freq_info_get(u32 freq)
106{
107 int i;
108
109 for (i = 0; i < ARRAY_SIZE(armada_37xx_dvfs); i++) {
110 if (freq == armada_37xx_dvfs[i].cpu_freq_max)
111 return &armada_37xx_dvfs[i];
112 }
113
114 pr_err("Unsupported CPU frequency %d MHz\n", freq/1000000);
115 return NULL;
116}
117
118/*
119 * Setup the four level managed by the hardware. Once the four level
120 * will be configured then the DVFS will be enabled.
121 */
122static void __init armada37xx_cpufreq_dvfs_setup(struct regmap *base,
123 struct clk *clk, u8 *divider)
124{
125 int load_lvl;
126 struct clk *parent;
127
128 for (load_lvl = 0; load_lvl < LOAD_LEVEL_NR; load_lvl++) {
129 unsigned int reg, mask, val, offset = 0;
130
131 if (load_lvl <= ARMADA_37XX_DVFS_LOAD_1)
132 reg = ARMADA_37XX_NB_L0L1;
133 else
134 reg = ARMADA_37XX_NB_L2L3;
135
136 if (load_lvl == ARMADA_37XX_DVFS_LOAD_0 ||
137 load_lvl == ARMADA_37XX_DVFS_LOAD_2)
138 offset += ARMADA_37XX_NB_CONFIG_SHIFT;
139
140 /* Set cpu clock source, for all the level we use TBG */
141 val = ARMADA_37XX_NB_CLK_SEL_TBG << ARMADA_37XX_NB_CLK_SEL_OFF;
142 mask = (ARMADA_37XX_NB_CLK_SEL_MASK
143 << ARMADA_37XX_NB_CLK_SEL_OFF);
144
145 /*
146 * Set cpu divider based on the pre-computed array in
147 * order to have balanced step.
148 */
149 val |= divider[load_lvl] << ARMADA_37XX_NB_TBG_DIV_OFF;
150 mask |= (ARMADA_37XX_NB_TBG_DIV_MASK
151 << ARMADA_37XX_NB_TBG_DIV_OFF);
152
153 /* Set VDD divider which is actually the load level. */
154 val |= load_lvl << ARMADA_37XX_NB_VDD_SEL_OFF;
155 mask |= (ARMADA_37XX_NB_VDD_SEL_MASK
156 << ARMADA_37XX_NB_VDD_SEL_OFF);
157
158 val <<= offset;
159 mask <<= offset;
160
161 regmap_update_bits(base, reg, mask, val);
162 }
163
164 /*
165 * Set cpu clock source, for all the level we keep the same
166 * clock source that the one already configured. For this one
167 * we need to use the clock framework
168 */
169 parent = clk_get_parent(clk);
170 clk_set_parent(clk, parent);
171}
172
173/*
174 * Find out the armada 37x supported AVS value whose voltage value is
175 * the round-up closest to the target voltage value.
176 */
177static u32 armada_37xx_avs_val_match(int target_vm)
178{
179 u32 avs;
180
181 /* Find out the round-up closest supported voltage value */
182 for (avs = 0; avs < ARRAY_SIZE(avs_map); avs++)
183 if (avs_map[avs] >= target_vm)
184 break;
185
186 /*
187 * If all supported voltages are smaller than target one,
188 * choose the largest supported voltage
189 */
190 if (avs == ARRAY_SIZE(avs_map))
191 avs = ARRAY_SIZE(avs_map) - 1;
192
193 return avs;
194}
195
196/*
197 * For Armada 37xx soc, L0(VSET0) VDD AVS value is set to SVC revision
198 * value or a default value when SVC is not supported.
199 * - L0 can be read out from the register of AVS_CTRL_0 and L0 voltage
200 * can be got from the mapping table of avs_map.
201 * - L1 voltage should be about 100mv smaller than L0 voltage
202 * - L2 & L3 voltage should be about 150mv smaller than L0 voltage.
203 * This function calculates L1 & L2 & L3 AVS values dynamically based
204 * on L0 voltage and fill all AVS values to the AVS value table.
205 */
206static void __init armada37xx_cpufreq_avs_configure(struct regmap *base,
207 struct armada_37xx_dvfs *dvfs)
208{
209 unsigned int target_vm;
210 int load_level = 0;
211 u32 l0_vdd_min;
212
213 if (base == NULL)
214 return;
215
216 /* Get L0 VDD min value */
217 regmap_read(base, ARMADA_37XX_AVS_CTL0, &l0_vdd_min);
218 l0_vdd_min = (l0_vdd_min >> ARMADA_37XX_AVS_LOW_VDD_LIMIT) &
219 ARMADA_37XX_AVS_VDD_MASK;
220 if (l0_vdd_min >= ARRAY_SIZE(avs_map)) {
221 pr_err("L0 VDD MIN %d is not correct.\n", l0_vdd_min);
222 return;
223 }
224 dvfs->avs[0] = l0_vdd_min;
225
226 if (avs_map[l0_vdd_min] <= MIN_VOLT_MV) {
227 /*
228 * If L0 voltage is smaller than 1000mv, then all VDD sets
229 * use L0 voltage;
230 */
231 u32 avs_min = armada_37xx_avs_val_match(MIN_VOLT_MV);
232
233 for (load_level = 1; load_level < LOAD_LEVEL_NR; load_level++)
234 dvfs->avs[load_level] = avs_min;
235
236 return;
237 }
238
239 /*
240 * L1 voltage is equal to L0 voltage - 100mv and it must be
241 * larger than 1000mv
242 */
243
244 target_vm = avs_map[l0_vdd_min] - 100;
245 target_vm = target_vm > MIN_VOLT_MV ? target_vm : MIN_VOLT_MV;
246 dvfs->avs[1] = armada_37xx_avs_val_match(target_vm);
247
248 /*
249 * L2 & L3 voltage is equal to L0 voltage - 150mv and it must
250 * be larger than 1000mv
251 */
252 target_vm = avs_map[l0_vdd_min] - 150;
253 target_vm = target_vm > MIN_VOLT_MV ? target_vm : MIN_VOLT_MV;
254 dvfs->avs[2] = dvfs->avs[3] = armada_37xx_avs_val_match(target_vm);
255}
256
257static void __init armada37xx_cpufreq_avs_setup(struct regmap *base,
258 struct armada_37xx_dvfs *dvfs)
259{
260 unsigned int avs_val = 0;
261 int load_level = 0;
262
263 if (base == NULL)
264 return;
265
266 /* Disable AVS before the configuration */
267 regmap_update_bits(base, ARMADA_37XX_AVS_CTL0,
268 ARMADA_37XX_AVS_ENABLE, 0);
269
270
271 /* Enable low voltage mode */
272 regmap_update_bits(base, ARMADA_37XX_AVS_CTL2,
273 ARMADA_37XX_AVS_LOW_VDD_EN,
274 ARMADA_37XX_AVS_LOW_VDD_EN);
275
276
277 for (load_level = 1; load_level < LOAD_LEVEL_NR; load_level++) {
278 avs_val = dvfs->avs[load_level];
279 regmap_update_bits(base, ARMADA_37XX_AVS_VSET(load_level-1),
280 ARMADA_37XX_AVS_VDD_MASK << ARMADA_37XX_AVS_HIGH_VDD_LIMIT |
281 ARMADA_37XX_AVS_VDD_MASK << ARMADA_37XX_AVS_LOW_VDD_LIMIT,
282 avs_val << ARMADA_37XX_AVS_HIGH_VDD_LIMIT |
283 avs_val << ARMADA_37XX_AVS_LOW_VDD_LIMIT);
284 }
285
286 /* Enable AVS after the configuration */
287 regmap_update_bits(base, ARMADA_37XX_AVS_CTL0,
288 ARMADA_37XX_AVS_ENABLE,
289 ARMADA_37XX_AVS_ENABLE);
290
291}
292
293static void armada37xx_cpufreq_disable_dvfs(struct regmap *base)
294{
295 unsigned int reg = ARMADA_37XX_NB_DYN_MOD,
296 mask = ARMADA_37XX_NB_DFS_EN;
297
298 regmap_update_bits(base, reg, mask, 0);
299}
300
301static void __init armada37xx_cpufreq_enable_dvfs(struct regmap *base)
302{
303 unsigned int val, reg = ARMADA_37XX_NB_CPU_LOAD,
304 mask = ARMADA_37XX_NB_CPU_LOAD_MASK;
305
306 /* Start with the highest load (0) */
307 val = ARMADA_37XX_DVFS_LOAD_0;
308 regmap_update_bits(base, reg, mask, val);
309
310 /* Now enable DVFS for the CPUs */
311 reg = ARMADA_37XX_NB_DYN_MOD;
312 mask = ARMADA_37XX_NB_CLK_SEL_EN | ARMADA_37XX_NB_TBG_EN |
313 ARMADA_37XX_NB_DIV_EN | ARMADA_37XX_NB_VDD_EN |
314 ARMADA_37XX_NB_DFS_EN;
315
316 regmap_update_bits(base, reg, mask, mask);
317}
318
319static int armada37xx_cpufreq_suspend(struct cpufreq_policy *policy)
320{
321 struct armada37xx_cpufreq_state *state = armada37xx_cpufreq_state;
322
323 regmap_read(state->regmap, ARMADA_37XX_NB_L0L1, &state->nb_l0l1);
324 regmap_read(state->regmap, ARMADA_37XX_NB_L2L3, &state->nb_l2l3);
325 regmap_read(state->regmap, ARMADA_37XX_NB_CPU_LOAD,
326 &state->nb_cpu_load);
327 regmap_read(state->regmap, ARMADA_37XX_NB_DYN_MOD, &state->nb_dyn_mod);
328
329 return 0;
330}
331
332static int armada37xx_cpufreq_resume(struct cpufreq_policy *policy)
333{
334 struct armada37xx_cpufreq_state *state = armada37xx_cpufreq_state;
335
336 /* Ensure DVFS is disabled otherwise the following registers are RO */
337 armada37xx_cpufreq_disable_dvfs(state->regmap);
338
339 regmap_write(state->regmap, ARMADA_37XX_NB_L0L1, state->nb_l0l1);
340 regmap_write(state->regmap, ARMADA_37XX_NB_L2L3, state->nb_l2l3);
341 regmap_write(state->regmap, ARMADA_37XX_NB_CPU_LOAD,
342 state->nb_cpu_load);
343
344 /*
345 * NB_DYN_MOD register is the one that actually enable back DVFS if it
346 * was enabled before the suspend operation. This must be done last
347 * otherwise other registers are not writable.
348 */
349 regmap_write(state->regmap, ARMADA_37XX_NB_DYN_MOD, state->nb_dyn_mod);
350
351 return 0;
352}
353
354static int __init armada37xx_cpufreq_driver_init(void)
355{
356 struct cpufreq_dt_platform_data pdata;
357 struct armada_37xx_dvfs *dvfs;
358 struct platform_device *pdev;
359 unsigned long freq;
360 unsigned int cur_frequency, base_frequency;
361 struct regmap *nb_pm_base, *avs_base;
362 struct device *cpu_dev;
363 int load_lvl, ret;
364 struct clk *clk, *parent;
365
366 nb_pm_base =
367 syscon_regmap_lookup_by_compatible("marvell,armada-3700-nb-pm");
368
369 if (IS_ERR(nb_pm_base))
370 return -ENODEV;
371
372 avs_base =
373 syscon_regmap_lookup_by_compatible("marvell,armada-3700-avs");
374
375 /* if AVS is not present don't use it but still try to setup dvfs */
376 if (IS_ERR(avs_base)) {
377 pr_info("Syscon failed for Adapting Voltage Scaling: skip it\n");
378 avs_base = NULL;
379 }
380 /* Before doing any configuration on the DVFS first, disable it */
381 armada37xx_cpufreq_disable_dvfs(nb_pm_base);
382
383 /*
384 * On CPU 0 register the operating points supported (which are
385 * the nominal CPU frequency and full integer divisions of
386 * it).
387 */
388 cpu_dev = get_cpu_device(0);
389 if (!cpu_dev) {
390 dev_err(cpu_dev, "Cannot get CPU\n");
391 return -ENODEV;
392 }
393
394 clk = clk_get(cpu_dev, 0);
395 if (IS_ERR(clk)) {
396 dev_err(cpu_dev, "Cannot get clock for CPU0\n");
397 return PTR_ERR(clk);
398 }
399
400 parent = clk_get_parent(clk);
401 if (IS_ERR(parent)) {
402 dev_err(cpu_dev, "Cannot get parent clock for CPU0\n");
403 clk_put(clk);
404 return PTR_ERR(parent);
405 }
406
407 /* Get parent CPU frequency */
408 base_frequency = clk_get_rate(parent);
409
410 if (!base_frequency) {
411 dev_err(cpu_dev, "Failed to get parent clock rate for CPU\n");
412 clk_put(clk);
413 return -EINVAL;
414 }
415
416 /* Get nominal (current) CPU frequency */
417 cur_frequency = clk_get_rate(clk);
418 if (!cur_frequency) {
419 dev_err(cpu_dev, "Failed to get clock rate for CPU\n");
420 clk_put(clk);
421 return -EINVAL;
422 }
423
424 dvfs = armada_37xx_cpu_freq_info_get(cur_frequency);
425 if (!dvfs) {
426 clk_put(clk);
427 return -EINVAL;
428 }
429
430 armada37xx_cpufreq_state = kmalloc(sizeof(*armada37xx_cpufreq_state),
431 GFP_KERNEL);
432 if (!armada37xx_cpufreq_state) {
433 clk_put(clk);
434 return -ENOMEM;
435 }
436
437 armada37xx_cpufreq_state->regmap = nb_pm_base;
438
439 armada37xx_cpufreq_avs_configure(avs_base, dvfs);
440 armada37xx_cpufreq_avs_setup(avs_base, dvfs);
441
442 armada37xx_cpufreq_dvfs_setup(nb_pm_base, clk, dvfs->divider);
443 clk_put(clk);
444
445 for (load_lvl = ARMADA_37XX_DVFS_LOAD_0; load_lvl < LOAD_LEVEL_NR;
446 load_lvl++) {
447 unsigned long u_volt = avs_map[dvfs->avs[load_lvl]] * 1000;
448 freq = base_frequency / dvfs->divider[load_lvl];
449 ret = dev_pm_opp_add(cpu_dev, freq, u_volt);
450 if (ret)
451 goto remove_opp;
452
453
454 }
455
456 /* Now that everything is setup, enable the DVFS at hardware level */
457 armada37xx_cpufreq_enable_dvfs(nb_pm_base);
458
459 pdata.suspend = armada37xx_cpufreq_suspend;
460 pdata.resume = armada37xx_cpufreq_resume;
461
462 pdev = platform_device_register_data(NULL, "cpufreq-dt", -1, &pdata,
463 sizeof(pdata));
464 ret = PTR_ERR_OR_ZERO(pdev);
465 if (ret)
466 goto disable_dvfs;
467
468 return 0;
469
470disable_dvfs:
471 armada37xx_cpufreq_disable_dvfs(nb_pm_base);
472remove_opp:
473 /* clean-up the already added opp before leaving */
474 while (load_lvl-- > ARMADA_37XX_DVFS_LOAD_0) {
475 freq = cur_frequency / dvfs->divider[load_lvl];
476 dev_pm_opp_remove(cpu_dev, freq);
477 }
478
479 kfree(armada37xx_cpufreq_state);
480
481 return ret;
482}
483/* late_initcall, to guarantee the driver is loaded after A37xx clock driver */
484late_initcall(armada37xx_cpufreq_driver_init);
485
486MODULE_AUTHOR("Gregory CLEMENT <gregory.clement@free-electrons.com>");
487MODULE_DESCRIPTION("Armada 37xx cpufreq driver");
488MODULE_LICENSE("GPL");