1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2013 Freescale Semiconductor, Inc.
4 */
5
6 #include <linux/clk.h>
7 #include <linux/cpu.h>
8 #include <linux/cpufreq.h>
9 #include <linux/err.h>
10 #include <linux/module.h>
11 #include <linux/nvmem-consumer.h>
12 #include <linux/of.h>
13 #include <linux/of_address.h>
14 #include <linux/pm_opp.h>
15 #include <linux/platform_device.h>
16 #include <linux/regulator/consumer.h>
17
18 #define PU_SOC_VOLTAGE_NORMAL 1250000
19 #define PU_SOC_VOLTAGE_HIGH 1275000
20 #define FREQ_1P2_GHZ 1200000000
21
22 static struct regulator *arm_reg;
23 static struct regulator *pu_reg;
24 static struct regulator *soc_reg;
25
26 enum IMX6_CPUFREQ_CLKS {
27 ARM,
28 PLL1_SYS,
29 STEP,
30 PLL1_SW,
31 PLL2_PFD2_396M,
32 /* MX6UL requires two more clks */
33 PLL2_BUS,
34 SECONDARY_SEL,
35 };
36 #define IMX6Q_CPUFREQ_CLK_NUM 5
37 #define IMX6UL_CPUFREQ_CLK_NUM 7
38
39 static int num_clks;
40 static struct clk_bulk_data clks[] = {
41 { .id = "arm" },
42 { .id = "pll1_sys" },
43 { .id = "step" },
44 { .id = "pll1_sw" },
45 { .id = "pll2_pfd2_396m" },
46 { .id = "pll2_bus" },
47 { .id = "secondary_sel" },
48 };
49
50 static struct device *cpu_dev;
51 static bool free_opp;
52 static struct cpufreq_frequency_table *freq_table;
53 static unsigned int max_freq;
54 static unsigned int transition_latency;
55
56 static u32 *imx6_soc_volt;
57 static u32 soc_opp_count;
58
imx6q_set_target(struct cpufreq_policy * policy,unsigned int index)59 static int imx6q_set_target(struct cpufreq_policy *policy, unsigned int index)
60 {
61 struct dev_pm_opp *opp;
62 unsigned long freq_hz, volt, volt_old;
63 unsigned int old_freq, new_freq;
64 bool pll1_sys_temp_enabled = false;
65 int ret;
66
67 new_freq = freq_table[index].frequency;
68 freq_hz = new_freq * 1000;
69 old_freq = clk_get_rate(clks[ARM].clk) / 1000;
70
71 opp = dev_pm_opp_find_freq_ceil(cpu_dev, &freq_hz);
72 if (IS_ERR(opp)) {
73 dev_err(cpu_dev, "failed to find OPP for %ld\n", freq_hz);
74 return PTR_ERR(opp);
75 }
76
77 volt = dev_pm_opp_get_voltage(opp);
78 dev_pm_opp_put(opp);
79
80 volt_old = regulator_get_voltage(arm_reg);
81
82 dev_dbg(cpu_dev, "%u MHz, %ld mV --> %u MHz, %ld mV\n",
83 old_freq / 1000, volt_old / 1000,
84 new_freq / 1000, volt / 1000);
85
86 /* scaling up? scale voltage before frequency */
87 if (new_freq > old_freq) {
88 if (!IS_ERR(pu_reg)) {
89 ret = regulator_set_voltage_tol(pu_reg, imx6_soc_volt[index], 0);
90 if (ret) {
91 dev_err(cpu_dev, "failed to scale vddpu up: %d\n", ret);
92 return ret;
93 }
94 }
95 ret = regulator_set_voltage_tol(soc_reg, imx6_soc_volt[index], 0);
96 if (ret) {
97 dev_err(cpu_dev, "failed to scale vddsoc up: %d\n", ret);
98 return ret;
99 }
100 ret = regulator_set_voltage_tol(arm_reg, volt, 0);
101 if (ret) {
102 dev_err(cpu_dev,
103 "failed to scale vddarm up: %d\n", ret);
104 return ret;
105 }
106 }
107
108 /*
109 * The setpoints are selected per PLL/PDF frequencies, so we need to
110 * reprogram PLL for frequency scaling. The procedure of reprogramming
111 * PLL1 is as below.
112 * For i.MX6UL, it has a secondary clk mux, the cpu frequency change
113 * flow is slightly different from other i.MX6 OSC.
114 * The cpu frequeny change flow for i.MX6(except i.MX6UL) is as below:
115 * - Enable pll2_pfd2_396m_clk and reparent pll1_sw_clk to it
116 * - Reprogram pll1_sys_clk and reparent pll1_sw_clk back to it
117 * - Disable pll2_pfd2_396m_clk
118 */
119 if (of_machine_is_compatible("fsl,imx6ul") ||
120 of_machine_is_compatible("fsl,imx6ull")) {
121 /*
122 * When changing pll1_sw_clk's parent to pll1_sys_clk,
123 * CPU may run at higher than 528MHz, this will lead to
124 * the system unstable if the voltage is lower than the
125 * voltage of 528MHz, so lower the CPU frequency to one
126 * half before changing CPU frequency.
127 */
128 clk_set_rate(clks[ARM].clk, (old_freq >> 1) * 1000);
129 clk_set_parent(clks[PLL1_SW].clk, clks[PLL1_SYS].clk);
130 if (freq_hz > clk_get_rate(clks[PLL2_PFD2_396M].clk))
131 clk_set_parent(clks[SECONDARY_SEL].clk,
132 clks[PLL2_BUS].clk);
133 else
134 clk_set_parent(clks[SECONDARY_SEL].clk,
135 clks[PLL2_PFD2_396M].clk);
136 clk_set_parent(clks[STEP].clk, clks[SECONDARY_SEL].clk);
137 clk_set_parent(clks[PLL1_SW].clk, clks[STEP].clk);
138 if (freq_hz > clk_get_rate(clks[PLL2_BUS].clk)) {
139 clk_set_rate(clks[PLL1_SYS].clk, new_freq * 1000);
140 clk_set_parent(clks[PLL1_SW].clk, clks[PLL1_SYS].clk);
141 }
142 } else {
143 clk_set_parent(clks[STEP].clk, clks[PLL2_PFD2_396M].clk);
144 clk_set_parent(clks[PLL1_SW].clk, clks[STEP].clk);
145 if (freq_hz > clk_get_rate(clks[PLL2_PFD2_396M].clk)) {
146 clk_set_rate(clks[PLL1_SYS].clk, new_freq * 1000);
147 clk_set_parent(clks[PLL1_SW].clk, clks[PLL1_SYS].clk);
148 } else {
149 /* pll1_sys needs to be enabled for divider rate change to work. */
150 pll1_sys_temp_enabled = true;
151 clk_prepare_enable(clks[PLL1_SYS].clk);
152 }
153 }
154
155 /* Ensure the arm clock divider is what we expect */
156 ret = clk_set_rate(clks[ARM].clk, new_freq * 1000);
157 if (ret) {
158 int ret1;
159
160 dev_err(cpu_dev, "failed to set clock rate: %d\n", ret);
161 ret1 = regulator_set_voltage_tol(arm_reg, volt_old, 0);
162 if (ret1)
163 dev_warn(cpu_dev,
164 "failed to restore vddarm voltage: %d\n", ret1);
165 return ret;
166 }
167
168 /* PLL1 is only needed until after ARM-PODF is set. */
169 if (pll1_sys_temp_enabled)
170 clk_disable_unprepare(clks[PLL1_SYS].clk);
171
172 /* scaling down? scale voltage after frequency */
173 if (new_freq < old_freq) {
174 ret = regulator_set_voltage_tol(arm_reg, volt, 0);
175 if (ret)
176 dev_warn(cpu_dev,
177 "failed to scale vddarm down: %d\n", ret);
178 ret = regulator_set_voltage_tol(soc_reg, imx6_soc_volt[index], 0);
179 if (ret)
180 dev_warn(cpu_dev, "failed to scale vddsoc down: %d\n", ret);
181 if (!IS_ERR(pu_reg)) {
182 ret = regulator_set_voltage_tol(pu_reg, imx6_soc_volt[index], 0);
183 if (ret)
184 dev_warn(cpu_dev, "failed to scale vddpu down: %d\n", ret);
185 }
186 }
187
188 return 0;
189 }
190
imx6q_cpufreq_init(struct cpufreq_policy * policy)191 static int imx6q_cpufreq_init(struct cpufreq_policy *policy)
192 {
193 policy->clk = clks[ARM].clk;
194 cpufreq_generic_init(policy, freq_table, transition_latency);
195 policy->suspend_freq = max_freq;
196 dev_pm_opp_of_register_em(policy->cpus);
197
198 return 0;
199 }
200
201 static struct cpufreq_driver imx6q_cpufreq_driver = {
202 .flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK |
203 CPUFREQ_IS_COOLING_DEV,
204 .verify = cpufreq_generic_frequency_table_verify,
205 .target_index = imx6q_set_target,
206 .get = cpufreq_generic_get,
207 .init = imx6q_cpufreq_init,
208 .name = "imx6q-cpufreq",
209 .attr = cpufreq_generic_attr,
210 .suspend = cpufreq_generic_suspend,
211 };
212
213 #define OCOTP_CFG3 0x440
214 #define OCOTP_CFG3_SPEED_SHIFT 16
215 #define OCOTP_CFG3_SPEED_1P2GHZ 0x3
216 #define OCOTP_CFG3_SPEED_996MHZ 0x2
217 #define OCOTP_CFG3_SPEED_852MHZ 0x1
218
imx6q_opp_check_speed_grading(struct device * dev)219 static void imx6q_opp_check_speed_grading(struct device *dev)
220 {
221 struct device_node *np;
222 void __iomem *base;
223 u32 val;
224
225 np = of_find_compatible_node(NULL, NULL, "fsl,imx6q-ocotp");
226 if (!np)
227 return;
228
229 base = of_iomap(np, 0);
230 if (!base) {
231 dev_err(dev, "failed to map ocotp\n");
232 goto put_node;
233 }
234
235 /*
236 * SPEED_GRADING[1:0] defines the max speed of ARM:
237 * 2b'11: 1200000000Hz;
238 * 2b'10: 996000000Hz;
239 * 2b'01: 852000000Hz; -- i.MX6Q Only, exclusive with 996MHz.
240 * 2b'00: 792000000Hz;
241 * We need to set the max speed of ARM according to fuse map.
242 */
243 val = readl_relaxed(base + OCOTP_CFG3);
244 val >>= OCOTP_CFG3_SPEED_SHIFT;
245 val &= 0x3;
246
247 if (val < OCOTP_CFG3_SPEED_996MHZ)
248 if (dev_pm_opp_disable(dev, 996000000))
249 dev_warn(dev, "failed to disable 996MHz OPP\n");
250
251 if (of_machine_is_compatible("fsl,imx6q") ||
252 of_machine_is_compatible("fsl,imx6qp")) {
253 if (val != OCOTP_CFG3_SPEED_852MHZ)
254 if (dev_pm_opp_disable(dev, 852000000))
255 dev_warn(dev, "failed to disable 852MHz OPP\n");
256 if (val != OCOTP_CFG3_SPEED_1P2GHZ)
257 if (dev_pm_opp_disable(dev, 1200000000))
258 dev_warn(dev, "failed to disable 1.2GHz OPP\n");
259 }
260 iounmap(base);
261 put_node:
262 of_node_put(np);
263 }
264
265 #define OCOTP_CFG3_6UL_SPEED_696MHZ 0x2
266 #define OCOTP_CFG3_6ULL_SPEED_792MHZ 0x2
267 #define OCOTP_CFG3_6ULL_SPEED_900MHZ 0x3
268
imx6ul_opp_check_speed_grading(struct device * dev)269 static int imx6ul_opp_check_speed_grading(struct device *dev)
270 {
271 u32 val;
272 int ret = 0;
273
274 if (of_find_property(dev->of_node, "nvmem-cells", NULL)) {
275 ret = nvmem_cell_read_u32(dev, "speed_grade", &val);
276 if (ret)
277 return ret;
278 } else {
279 struct device_node *np;
280 void __iomem *base;
281
282 np = of_find_compatible_node(NULL, NULL, "fsl,imx6ul-ocotp");
283 if (!np)
284 return -ENOENT;
285
286 base = of_iomap(np, 0);
287 of_node_put(np);
288 if (!base) {
289 dev_err(dev, "failed to map ocotp\n");
290 return -EFAULT;
291 }
292
293 val = readl_relaxed(base + OCOTP_CFG3);
294 iounmap(base);
295 }
296
297 /*
298 * Speed GRADING[1:0] defines the max speed of ARM:
299 * 2b'00: Reserved;
300 * 2b'01: 528000000Hz;
301 * 2b'10: 696000000Hz on i.MX6UL, 792000000Hz on i.MX6ULL;
302 * 2b'11: 900000000Hz on i.MX6ULL only;
303 * We need to set the max speed of ARM according to fuse map.
304 */
305 val >>= OCOTP_CFG3_SPEED_SHIFT;
306 val &= 0x3;
307
308 if (of_machine_is_compatible("fsl,imx6ul")) {
309 if (val != OCOTP_CFG3_6UL_SPEED_696MHZ)
310 if (dev_pm_opp_disable(dev, 696000000))
311 dev_warn(dev, "failed to disable 696MHz OPP\n");
312 }
313
314 if (of_machine_is_compatible("fsl,imx6ull")) {
315 if (val != OCOTP_CFG3_6ULL_SPEED_792MHZ)
316 if (dev_pm_opp_disable(dev, 792000000))
317 dev_warn(dev, "failed to disable 792MHz OPP\n");
318
319 if (val != OCOTP_CFG3_6ULL_SPEED_900MHZ)
320 if (dev_pm_opp_disable(dev, 900000000))
321 dev_warn(dev, "failed to disable 900MHz OPP\n");
322 }
323
324 return ret;
325 }
326
imx6q_cpufreq_probe(struct platform_device * pdev)327 static int imx6q_cpufreq_probe(struct platform_device *pdev)
328 {
329 struct device_node *np;
330 struct dev_pm_opp *opp;
331 unsigned long min_volt, max_volt;
332 int num, ret;
333 const struct property *prop;
334 const __be32 *val;
335 u32 nr, i, j;
336
337 cpu_dev = get_cpu_device(0);
338 if (!cpu_dev) {
339 pr_err("failed to get cpu0 device\n");
340 return -ENODEV;
341 }
342
343 np = of_node_get(cpu_dev->of_node);
344 if (!np) {
345 dev_err(cpu_dev, "failed to find cpu0 node\n");
346 return -ENOENT;
347 }
348
349 if (of_machine_is_compatible("fsl,imx6ul") ||
350 of_machine_is_compatible("fsl,imx6ull"))
351 num_clks = IMX6UL_CPUFREQ_CLK_NUM;
352 else
353 num_clks = IMX6Q_CPUFREQ_CLK_NUM;
354
355 ret = clk_bulk_get(cpu_dev, num_clks, clks);
356 if (ret)
357 goto put_node;
358
359 arm_reg = regulator_get(cpu_dev, "arm");
360 pu_reg = regulator_get_optional(cpu_dev, "pu");
361 soc_reg = regulator_get(cpu_dev, "soc");
362 if (PTR_ERR(arm_reg) == -EPROBE_DEFER ||
363 PTR_ERR(soc_reg) == -EPROBE_DEFER ||
364 PTR_ERR(pu_reg) == -EPROBE_DEFER) {
365 ret = -EPROBE_DEFER;
366 dev_dbg(cpu_dev, "regulators not ready, defer\n");
367 goto put_reg;
368 }
369 if (IS_ERR(arm_reg) || IS_ERR(soc_reg)) {
370 dev_err(cpu_dev, "failed to get regulators\n");
371 ret = -ENOENT;
372 goto put_reg;
373 }
374
375 ret = dev_pm_opp_of_add_table(cpu_dev);
376 if (ret < 0) {
377 dev_err(cpu_dev, "failed to init OPP table: %d\n", ret);
378 goto put_reg;
379 }
380
381 if (of_machine_is_compatible("fsl,imx6ul") ||
382 of_machine_is_compatible("fsl,imx6ull")) {
383 ret = imx6ul_opp_check_speed_grading(cpu_dev);
384 if (ret) {
385 if (ret == -EPROBE_DEFER)
386 goto put_node;
387
388 dev_err(cpu_dev, "failed to read ocotp: %d\n",
389 ret);
390 goto put_node;
391 }
392 } else {
393 imx6q_opp_check_speed_grading(cpu_dev);
394 }
395
396 /* Because we have added the OPPs here, we must free them */
397 free_opp = true;
398 num = dev_pm_opp_get_opp_count(cpu_dev);
399 if (num < 0) {
400 ret = num;
401 dev_err(cpu_dev, "no OPP table is found: %d\n", ret);
402 goto out_free_opp;
403 }
404
405 ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
406 if (ret) {
407 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
408 goto out_free_opp;
409 }
410
411 /* Make imx6_soc_volt array's size same as arm opp number */
412 imx6_soc_volt = devm_kcalloc(cpu_dev, num, sizeof(*imx6_soc_volt),
413 GFP_KERNEL);
414 if (imx6_soc_volt == NULL) {
415 ret = -ENOMEM;
416 goto free_freq_table;
417 }
418
419 prop = of_find_property(np, "fsl,soc-operating-points", NULL);
420 if (!prop || !prop->value)
421 goto soc_opp_out;
422
423 /*
424 * Each OPP is a set of tuples consisting of frequency and
425 * voltage like <freq-kHz vol-uV>.
426 */
427 nr = prop->length / sizeof(u32);
428 if (nr % 2 || (nr / 2) < num)
429 goto soc_opp_out;
430
431 for (j = 0; j < num; j++) {
432 val = prop->value;
433 for (i = 0; i < nr / 2; i++) {
434 unsigned long freq = be32_to_cpup(val++);
435 unsigned long volt = be32_to_cpup(val++);
436 if (freq_table[j].frequency == freq) {
437 imx6_soc_volt[soc_opp_count++] = volt;
438 break;
439 }
440 }
441 }
442
443 soc_opp_out:
444 /* use fixed soc opp volt if no valid soc opp info found in dtb */
445 if (soc_opp_count != num) {
446 dev_warn(cpu_dev, "can NOT find valid fsl,soc-operating-points property in dtb, use default value!\n");
447 for (j = 0; j < num; j++)
448 imx6_soc_volt[j] = PU_SOC_VOLTAGE_NORMAL;
449 if (freq_table[num - 1].frequency * 1000 == FREQ_1P2_GHZ)
450 imx6_soc_volt[num - 1] = PU_SOC_VOLTAGE_HIGH;
451 }
452
453 if (of_property_read_u32(np, "clock-latency", &transition_latency))
454 transition_latency = CPUFREQ_ETERNAL;
455
456 /*
457 * Calculate the ramp time for max voltage change in the
458 * VDDSOC and VDDPU regulators.
459 */
460 ret = regulator_set_voltage_time(soc_reg, imx6_soc_volt[0], imx6_soc_volt[num - 1]);
461 if (ret > 0)
462 transition_latency += ret * 1000;
463 if (!IS_ERR(pu_reg)) {
464 ret = regulator_set_voltage_time(pu_reg, imx6_soc_volt[0], imx6_soc_volt[num - 1]);
465 if (ret > 0)
466 transition_latency += ret * 1000;
467 }
468
469 /*
470 * OPP is maintained in order of increasing frequency, and
471 * freq_table initialised from OPP is therefore sorted in the
472 * same order.
473 */
474 max_freq = freq_table[--num].frequency;
475 opp = dev_pm_opp_find_freq_exact(cpu_dev,
476 freq_table[0].frequency * 1000, true);
477 min_volt = dev_pm_opp_get_voltage(opp);
478 dev_pm_opp_put(opp);
479 opp = dev_pm_opp_find_freq_exact(cpu_dev, max_freq * 1000, true);
480 max_volt = dev_pm_opp_get_voltage(opp);
481 dev_pm_opp_put(opp);
482
483 ret = regulator_set_voltage_time(arm_reg, min_volt, max_volt);
484 if (ret > 0)
485 transition_latency += ret * 1000;
486
487 ret = cpufreq_register_driver(&imx6q_cpufreq_driver);
488 if (ret) {
489 dev_err(cpu_dev, "failed register driver: %d\n", ret);
490 goto free_freq_table;
491 }
492
493 of_node_put(np);
494 return 0;
495
496 free_freq_table:
497 dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
498 out_free_opp:
499 if (free_opp)
500 dev_pm_opp_of_remove_table(cpu_dev);
501 put_reg:
502 if (!IS_ERR(arm_reg))
503 regulator_put(arm_reg);
504 if (!IS_ERR(pu_reg))
505 regulator_put(pu_reg);
506 if (!IS_ERR(soc_reg))
507 regulator_put(soc_reg);
508
509 clk_bulk_put(num_clks, clks);
510 put_node:
511 of_node_put(np);
512
513 return ret;
514 }
515
imx6q_cpufreq_remove(struct platform_device * pdev)516 static int imx6q_cpufreq_remove(struct platform_device *pdev)
517 {
518 cpufreq_unregister_driver(&imx6q_cpufreq_driver);
519 dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
520 if (free_opp)
521 dev_pm_opp_of_remove_table(cpu_dev);
522 regulator_put(arm_reg);
523 if (!IS_ERR(pu_reg))
524 regulator_put(pu_reg);
525 regulator_put(soc_reg);
526
527 clk_bulk_put(num_clks, clks);
528
529 return 0;
530 }
531
532 static struct platform_driver imx6q_cpufreq_platdrv = {
533 .driver = {
534 .name = "imx6q-cpufreq",
535 },
536 .probe = imx6q_cpufreq_probe,
537 .remove = imx6q_cpufreq_remove,
538 };
539 module_platform_driver(imx6q_cpufreq_platdrv);
540
541 MODULE_ALIAS("platform:imx6q-cpufreq");
542 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
543 MODULE_DESCRIPTION("Freescale i.MX6Q cpufreq driver");
544 MODULE_LICENSE("GPL");
545
