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1/*
2 * Versatile Express Serial Power Controller (SPC) support
3 *
4 * Copyright (C) 2013 ARM Ltd.
5 *
6 * Authors: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
7 * Achin Gupta <achin.gupta@arm.com>
8 * Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2 as
12 * published by the Free Software Foundation.
13 *
14 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
15 * kind, whether express or implied; without even the implied warranty
16 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
18 */
19
20#include <linux/clk-provider.h>
21#include <linux/clkdev.h>
22#include <linux/cpu.h>
23#include <linux/delay.h>
24#include <linux/err.h>
25#include <linux/interrupt.h>
26#include <linux/io.h>
27#include <linux/platform_device.h>
28#include <linux/pm_opp.h>
29#include <linux/slab.h>
30#include <linux/semaphore.h>
31
32#include <asm/cacheflush.h>
33
34#define SPCLOG "vexpress-spc: "
35
36#define PERF_LVL_A15 0x00
37#define PERF_REQ_A15 0x04
38#define PERF_LVL_A7 0x08
39#define PERF_REQ_A7 0x0c
40#define COMMS 0x10
41#define COMMS_REQ 0x14
42#define PWC_STATUS 0x18
43#define PWC_FLAG 0x1c
44
45/* SPC wake-up IRQs status and mask */
46#define WAKE_INT_MASK 0x24
47#define WAKE_INT_RAW 0x28
48#define WAKE_INT_STAT 0x2c
49/* SPC power down registers */
50#define A15_PWRDN_EN 0x30
51#define A7_PWRDN_EN 0x34
52/* SPC per-CPU mailboxes */
53#define A15_BX_ADDR0 0x68
54#define A7_BX_ADDR0 0x78
55
56/* SPC CPU/cluster reset statue */
57#define STANDBYWFI_STAT 0x3c
58#define STANDBYWFI_STAT_A15_CPU_MASK(cpu) (1 << (cpu))
59#define STANDBYWFI_STAT_A7_CPU_MASK(cpu) (1 << (3 + (cpu)))
60
61/* SPC system config interface registers */
62#define SYSCFG_WDATA 0x70
63#define SYSCFG_RDATA 0x74
64
65/* A15/A7 OPP virtual register base */
66#define A15_PERFVAL_BASE 0xC10
67#define A7_PERFVAL_BASE 0xC30
68
69/* Config interface control bits */
70#define SYSCFG_START (1 << 31)
71#define SYSCFG_SCC (6 << 20)
72#define SYSCFG_STAT (14 << 20)
73
74/* wake-up interrupt masks */
75#define GBL_WAKEUP_INT_MSK (0x3 << 10)
76
77/* TC2 static dual-cluster configuration */
78#define MAX_CLUSTERS 2
79
80/*
81 * Even though the SPC takes max 3-5 ms to complete any OPP/COMMS
82 * operation, the operation could start just before jiffie is about
83 * to be incremented. So setting timeout value of 20ms = 2jiffies@100Hz
84 */
85#define TIMEOUT_US 20000
86
87#define MAX_OPPS 8
88#define CA15_DVFS 0
89#define CA7_DVFS 1
90#define SPC_SYS_CFG 2
91#define STAT_COMPLETE(type) ((1 << 0) << (type << 2))
92#define STAT_ERR(type) ((1 << 1) << (type << 2))
93#define RESPONSE_MASK(type) (STAT_COMPLETE(type) | STAT_ERR(type))
94
95struct ve_spc_opp {
96 unsigned long freq;
97 unsigned long u_volt;
98};
99
100struct ve_spc_drvdata {
101 void __iomem *baseaddr;
102 /*
103 * A15s cluster identifier
104 * It corresponds to A15 processors MPIDR[15:8] bitfield
105 */
106 u32 a15_clusid;
107 uint32_t cur_rsp_mask;
108 uint32_t cur_rsp_stat;
109 struct semaphore sem;
110 struct completion done;
111 struct ve_spc_opp *opps[MAX_CLUSTERS];
112 int num_opps[MAX_CLUSTERS];
113};
114
115static struct ve_spc_drvdata *info;
116
117static inline bool cluster_is_a15(u32 cluster)
118{
119 return cluster == info->a15_clusid;
120}
121
122/**
123 * ve_spc_global_wakeup_irq()
124 *
125 * Function to set/clear global wakeup IRQs. Not protected by locking since
126 * it might be used in code paths where normal cacheable locks are not
127 * working. Locking must be provided by the caller to ensure atomicity.
128 *
129 * @set: if true, global wake-up IRQs are set, if false they are cleared
130 */
131void ve_spc_global_wakeup_irq(bool set)
132{
133 u32 reg;
134
135 reg = readl_relaxed(info->baseaddr + WAKE_INT_MASK);
136
137 if (set)
138 reg |= GBL_WAKEUP_INT_MSK;
139 else
140 reg &= ~GBL_WAKEUP_INT_MSK;
141
142 writel_relaxed(reg, info->baseaddr + WAKE_INT_MASK);
143}
144
145/**
146 * ve_spc_cpu_wakeup_irq()
147 *
148 * Function to set/clear per-CPU wake-up IRQs. Not protected by locking since
149 * it might be used in code paths where normal cacheable locks are not
150 * working. Locking must be provided by the caller to ensure atomicity.
151 *
152 * @cluster: mpidr[15:8] bitfield describing cluster affinity level
153 * @cpu: mpidr[7:0] bitfield describing cpu affinity level
154 * @set: if true, wake-up IRQs are set, if false they are cleared
155 */
156void ve_spc_cpu_wakeup_irq(u32 cluster, u32 cpu, bool set)
157{
158 u32 mask, reg;
159
160 if (cluster >= MAX_CLUSTERS)
161 return;
162
163 mask = 1 << cpu;
164
165 if (!cluster_is_a15(cluster))
166 mask <<= 4;
167
168 reg = readl_relaxed(info->baseaddr + WAKE_INT_MASK);
169
170 if (set)
171 reg |= mask;
172 else
173 reg &= ~mask;
174
175 writel_relaxed(reg, info->baseaddr + WAKE_INT_MASK);
176}
177
178/**
179 * ve_spc_set_resume_addr() - set the jump address used for warm boot
180 *
181 * @cluster: mpidr[15:8] bitfield describing cluster affinity level
182 * @cpu: mpidr[7:0] bitfield describing cpu affinity level
183 * @addr: physical resume address
184 */
185void ve_spc_set_resume_addr(u32 cluster, u32 cpu, u32 addr)
186{
187 void __iomem *baseaddr;
188
189 if (cluster >= MAX_CLUSTERS)
190 return;
191
192 if (cluster_is_a15(cluster))
193 baseaddr = info->baseaddr + A15_BX_ADDR0 + (cpu << 2);
194 else
195 baseaddr = info->baseaddr + A7_BX_ADDR0 + (cpu << 2);
196
197 writel_relaxed(addr, baseaddr);
198}
199
200/**
201 * ve_spc_powerdown()
202 *
203 * Function to enable/disable cluster powerdown. Not protected by locking
204 * since it might be used in code paths where normal cacheable locks are not
205 * working. Locking must be provided by the caller to ensure atomicity.
206 *
207 * @cluster: mpidr[15:8] bitfield describing cluster affinity level
208 * @enable: if true enables powerdown, if false disables it
209 */
210void ve_spc_powerdown(u32 cluster, bool enable)
211{
212 u32 pwdrn_reg;
213
214 if (cluster >= MAX_CLUSTERS)
215 return;
216
217 pwdrn_reg = cluster_is_a15(cluster) ? A15_PWRDN_EN : A7_PWRDN_EN;
218 writel_relaxed(enable, info->baseaddr + pwdrn_reg);
219}
220
221static u32 standbywfi_cpu_mask(u32 cpu, u32 cluster)
222{
223 return cluster_is_a15(cluster) ?
224 STANDBYWFI_STAT_A15_CPU_MASK(cpu)
225 : STANDBYWFI_STAT_A7_CPU_MASK(cpu);
226}
227
228/**
229 * ve_spc_cpu_in_wfi(u32 cpu, u32 cluster)
230 *
231 * @cpu: mpidr[7:0] bitfield describing CPU affinity level within cluster
232 * @cluster: mpidr[15:8] bitfield describing cluster affinity level
233 *
234 * @return: non-zero if and only if the specified CPU is in WFI
235 *
236 * Take care when interpreting the result of this function: a CPU might
237 * be in WFI temporarily due to idle, and is not necessarily safely
238 * parked.
239 */
240int ve_spc_cpu_in_wfi(u32 cpu, u32 cluster)
241{
242 int ret;
243 u32 mask = standbywfi_cpu_mask(cpu, cluster);
244
245 if (cluster >= MAX_CLUSTERS)
246 return 1;
247
248 ret = readl_relaxed(info->baseaddr + STANDBYWFI_STAT);
249
250 pr_debug("%s: PCFGREG[0x%X] = 0x%08X, mask = 0x%X\n",
251 __func__, STANDBYWFI_STAT, ret, mask);
252
253 return ret & mask;
254}
255
256static int ve_spc_get_performance(int cluster, u32 *freq)
257{
258 struct ve_spc_opp *opps = info->opps[cluster];
259 u32 perf_cfg_reg = 0;
260 u32 perf;
261
262 perf_cfg_reg = cluster_is_a15(cluster) ? PERF_LVL_A15 : PERF_LVL_A7;
263
264 perf = readl_relaxed(info->baseaddr + perf_cfg_reg);
265 if (perf >= info->num_opps[cluster])
266 return -EINVAL;
267
268 opps += perf;
269 *freq = opps->freq;
270
271 return 0;
272}
273
274/* find closest match to given frequency in OPP table */
275static int ve_spc_round_performance(int cluster, u32 freq)
276{
277 int idx, max_opp = info->num_opps[cluster];
278 struct ve_spc_opp *opps = info->opps[cluster];
279 u32 fmin = 0, fmax = ~0, ftmp;
280
281 freq /= 1000; /* OPP entries in kHz */
282 for (idx = 0; idx < max_opp; idx++, opps++) {
283 ftmp = opps->freq;
284 if (ftmp >= freq) {
285 if (ftmp <= fmax)
286 fmax = ftmp;
287 } else {
288 if (ftmp >= fmin)
289 fmin = ftmp;
290 }
291 }
292 if (fmax != ~0)
293 return fmax * 1000;
294 else
295 return fmin * 1000;
296}
297
298static int ve_spc_find_performance_index(int cluster, u32 freq)
299{
300 int idx, max_opp = info->num_opps[cluster];
301 struct ve_spc_opp *opps = info->opps[cluster];
302
303 for (idx = 0; idx < max_opp; idx++, opps++)
304 if (opps->freq == freq)
305 break;
306 return (idx == max_opp) ? -EINVAL : idx;
307}
308
309static int ve_spc_waitforcompletion(int req_type)
310{
311 int ret = wait_for_completion_interruptible_timeout(
312 &info->done, usecs_to_jiffies(TIMEOUT_US));
313 if (ret == 0)
314 ret = -ETIMEDOUT;
315 else if (ret > 0)
316 ret = info->cur_rsp_stat & STAT_COMPLETE(req_type) ? 0 : -EIO;
317 return ret;
318}
319
320static int ve_spc_set_performance(int cluster, u32 freq)
321{
322 u32 perf_cfg_reg, perf_stat_reg;
323 int ret, perf, req_type;
324
325 if (cluster_is_a15(cluster)) {
326 req_type = CA15_DVFS;
327 perf_cfg_reg = PERF_LVL_A15;
328 perf_stat_reg = PERF_REQ_A15;
329 } else {
330 req_type = CA7_DVFS;
331 perf_cfg_reg = PERF_LVL_A7;
332 perf_stat_reg = PERF_REQ_A7;
333 }
334
335 perf = ve_spc_find_performance_index(cluster, freq);
336
337 if (perf < 0)
338 return perf;
339
340 if (down_timeout(&info->sem, usecs_to_jiffies(TIMEOUT_US)))
341 return -ETIME;
342
343 init_completion(&info->done);
344 info->cur_rsp_mask = RESPONSE_MASK(req_type);
345
346 writel(perf, info->baseaddr + perf_cfg_reg);
347 ret = ve_spc_waitforcompletion(req_type);
348
349 info->cur_rsp_mask = 0;
350 up(&info->sem);
351
352 return ret;
353}
354
355static int ve_spc_read_sys_cfg(int func, int offset, uint32_t *data)
356{
357 int ret;
358
359 if (down_timeout(&info->sem, usecs_to_jiffies(TIMEOUT_US)))
360 return -ETIME;
361
362 init_completion(&info->done);
363 info->cur_rsp_mask = RESPONSE_MASK(SPC_SYS_CFG);
364
365 /* Set the control value */
366 writel(SYSCFG_START | func | offset >> 2, info->baseaddr + COMMS);
367 ret = ve_spc_waitforcompletion(SPC_SYS_CFG);
368
369 if (ret == 0)
370 *data = readl(info->baseaddr + SYSCFG_RDATA);
371
372 info->cur_rsp_mask = 0;
373 up(&info->sem);
374
375 return ret;
376}
377
378static irqreturn_t ve_spc_irq_handler(int irq, void *data)
379{
380 struct ve_spc_drvdata *drv_data = data;
381 uint32_t status = readl_relaxed(drv_data->baseaddr + PWC_STATUS);
382
383 if (info->cur_rsp_mask & status) {
384 info->cur_rsp_stat = status;
385 complete(&drv_data->done);
386 }
387
388 return IRQ_HANDLED;
389}
390
391/*
392 * +--------------------------+
393 * | 31 20 | 19 0 |
394 * +--------------------------+
395 * | m_volt | freq(kHz) |
396 * +--------------------------+
397 */
398#define MULT_FACTOR 20
399#define VOLT_SHIFT 20
400#define FREQ_MASK (0xFFFFF)
401static int ve_spc_populate_opps(uint32_t cluster)
402{
403 uint32_t data = 0, off, ret, idx;
404 struct ve_spc_opp *opps;
405
406 opps = kzalloc(sizeof(*opps) * MAX_OPPS, GFP_KERNEL);
407 if (!opps)
408 return -ENOMEM;
409
410 info->opps[cluster] = opps;
411
412 off = cluster_is_a15(cluster) ? A15_PERFVAL_BASE : A7_PERFVAL_BASE;
413 for (idx = 0; idx < MAX_OPPS; idx++, off += 4, opps++) {
414 ret = ve_spc_read_sys_cfg(SYSCFG_SCC, off, &data);
415 if (!ret) {
416 opps->freq = (data & FREQ_MASK) * MULT_FACTOR;
417 opps->u_volt = (data >> VOLT_SHIFT) * 1000;
418 } else {
419 break;
420 }
421 }
422 info->num_opps[cluster] = idx;
423
424 return ret;
425}
426
427static int ve_init_opp_table(struct device *cpu_dev)
428{
429 int cluster = topology_physical_package_id(cpu_dev->id);
430 int idx, ret = 0, max_opp = info->num_opps[cluster];
431 struct ve_spc_opp *opps = info->opps[cluster];
432
433 for (idx = 0; idx < max_opp; idx++, opps++) {
434 ret = dev_pm_opp_add(cpu_dev, opps->freq * 1000, opps->u_volt);
435 if (ret) {
436 dev_warn(cpu_dev, "failed to add opp %lu %lu\n",
437 opps->freq, opps->u_volt);
438 return ret;
439 }
440 }
441 return ret;
442}
443
444int __init ve_spc_init(void __iomem *baseaddr, u32 a15_clusid, int irq)
445{
446 int ret;
447 info = kzalloc(sizeof(*info), GFP_KERNEL);
448 if (!info) {
449 pr_err(SPCLOG "unable to allocate mem\n");
450 return -ENOMEM;
451 }
452
453 info->baseaddr = baseaddr;
454 info->a15_clusid = a15_clusid;
455
456 if (irq <= 0) {
457 pr_err(SPCLOG "Invalid IRQ %d\n", irq);
458 kfree(info);
459 return -EINVAL;
460 }
461
462 init_completion(&info->done);
463
464 readl_relaxed(info->baseaddr + PWC_STATUS);
465
466 ret = request_irq(irq, ve_spc_irq_handler, IRQF_TRIGGER_HIGH
467 | IRQF_ONESHOT, "vexpress-spc", info);
468 if (ret) {
469 pr_err(SPCLOG "IRQ %d request failed\n", irq);
470 kfree(info);
471 return -ENODEV;
472 }
473
474 sema_init(&info->sem, 1);
475 /*
476 * Multi-cluster systems may need this data when non-coherent, during
477 * cluster power-up/power-down. Make sure driver info reaches main
478 * memory.
479 */
480 sync_cache_w(info);
481 sync_cache_w(&info);
482
483 return 0;
484}
485
486struct clk_spc {
487 struct clk_hw hw;
488 int cluster;
489};
490
491#define to_clk_spc(spc) container_of(spc, struct clk_spc, hw)
492static unsigned long spc_recalc_rate(struct clk_hw *hw,
493 unsigned long parent_rate)
494{
495 struct clk_spc *spc = to_clk_spc(hw);
496 u32 freq;
497
498 if (ve_spc_get_performance(spc->cluster, &freq))
499 return -EIO;
500
501 return freq * 1000;
502}
503
504static long spc_round_rate(struct clk_hw *hw, unsigned long drate,
505 unsigned long *parent_rate)
506{
507 struct clk_spc *spc = to_clk_spc(hw);
508
509 return ve_spc_round_performance(spc->cluster, drate);
510}
511
512static int spc_set_rate(struct clk_hw *hw, unsigned long rate,
513 unsigned long parent_rate)
514{
515 struct clk_spc *spc = to_clk_spc(hw);
516
517 return ve_spc_set_performance(spc->cluster, rate / 1000);
518}
519
520static struct clk_ops clk_spc_ops = {
521 .recalc_rate = spc_recalc_rate,
522 .round_rate = spc_round_rate,
523 .set_rate = spc_set_rate,
524};
525
526static struct clk *ve_spc_clk_register(struct device *cpu_dev)
527{
528 struct clk_init_data init;
529 struct clk_spc *spc;
530
531 spc = kzalloc(sizeof(*spc), GFP_KERNEL);
532 if (!spc) {
533 pr_err("could not allocate spc clk\n");
534 return ERR_PTR(-ENOMEM);
535 }
536
537 spc->hw.init = &init;
538 spc->cluster = topology_physical_package_id(cpu_dev->id);
539
540 init.name = dev_name(cpu_dev);
541 init.ops = &clk_spc_ops;
542 init.flags = CLK_IS_ROOT | CLK_GET_RATE_NOCACHE;
543 init.num_parents = 0;
544
545 return devm_clk_register(cpu_dev, &spc->hw);
546}
547
548static int __init ve_spc_clk_init(void)
549{
550 int cpu;
551 struct clk *clk;
552
553 if (!info)
554 return 0; /* Continue only if SPC is initialised */
555
556 if (ve_spc_populate_opps(0) || ve_spc_populate_opps(1)) {
557 pr_err("failed to build OPP table\n");
558 return -ENODEV;
559 }
560
561 for_each_possible_cpu(cpu) {
562 struct device *cpu_dev = get_cpu_device(cpu);
563 if (!cpu_dev) {
564 pr_warn("failed to get cpu%d device\n", cpu);
565 continue;
566 }
567 clk = ve_spc_clk_register(cpu_dev);
568 if (IS_ERR(clk)) {
569 pr_warn("failed to register cpu%d clock\n", cpu);
570 continue;
571 }
572 if (clk_register_clkdev(clk, NULL, dev_name(cpu_dev))) {
573 pr_warn("failed to register cpu%d clock lookup\n", cpu);
574 continue;
575 }
576
577 if (ve_init_opp_table(cpu_dev))
578 pr_warn("failed to initialise cpu%d opp table\n", cpu);
579 }
580
581 platform_device_register_simple("vexpress-spc-cpufreq", -1, NULL, 0);
582 return 0;
583}
584module_init(ve_spc_clk_init);