xref: /openbmc/linux/arch/arm/mach-mvebu/pmsu.c (revision 4f6cce39)
1 /*
2  * Power Management Service Unit(PMSU) support for Armada 370/XP platforms.
3  *
4  * Copyright (C) 2012 Marvell
5  *
6  * Yehuda Yitschak <yehuday@marvell.com>
7  * Gregory Clement <gregory.clement@free-electrons.com>
8  * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
9  *
10  * This file is licensed under the terms of the GNU General Public
11  * License version 2.  This program is licensed "as is" without any
12  * warranty of any kind, whether express or implied.
13  *
14  * The Armada 370 and Armada XP SOCs have a power management service
15  * unit which is responsible for powering down and waking up CPUs and
16  * other SOC units
17  */
18 
19 #define pr_fmt(fmt) "mvebu-pmsu: " fmt
20 
21 #include <linux/clk.h>
22 #include <linux/cpu_pm.h>
23 #include <linux/delay.h>
24 #include <linux/init.h>
25 #include <linux/io.h>
26 #include <linux/kernel.h>
27 #include <linux/mbus.h>
28 #include <linux/mvebu-pmsu.h>
29 #include <linux/of_address.h>
30 #include <linux/of_device.h>
31 #include <linux/platform_device.h>
32 #include <linux/resource.h>
33 #include <linux/slab.h>
34 #include <linux/smp.h>
35 #include <asm/cacheflush.h>
36 #include <asm/cp15.h>
37 #include <asm/smp_scu.h>
38 #include <asm/smp_plat.h>
39 #include <asm/suspend.h>
40 #include <asm/tlbflush.h>
41 #include "common.h"
42 #include "pmsu.h"
43 
44 #define PMSU_BASE_OFFSET    0x100
45 #define PMSU_REG_SIZE	    0x1000
46 
47 /* PMSU MP registers */
48 #define PMSU_CONTROL_AND_CONFIG(cpu)	    ((cpu * 0x100) + 0x104)
49 #define PMSU_CONTROL_AND_CONFIG_DFS_REQ		BIT(18)
50 #define PMSU_CONTROL_AND_CONFIG_PWDDN_REQ	BIT(16)
51 #define PMSU_CONTROL_AND_CONFIG_L2_PWDDN	BIT(20)
52 
53 #define PMSU_CPU_POWER_DOWN_CONTROL(cpu)    ((cpu * 0x100) + 0x108)
54 
55 #define PMSU_CPU_POWER_DOWN_DIS_SNP_Q_SKIP	BIT(0)
56 
57 #define PMSU_STATUS_AND_MASK(cpu)	    ((cpu * 0x100) + 0x10c)
58 #define PMSU_STATUS_AND_MASK_CPU_IDLE_WAIT	BIT(16)
59 #define PMSU_STATUS_AND_MASK_SNP_Q_EMPTY_WAIT	BIT(17)
60 #define PMSU_STATUS_AND_MASK_IRQ_WAKEUP		BIT(20)
61 #define PMSU_STATUS_AND_MASK_FIQ_WAKEUP		BIT(21)
62 #define PMSU_STATUS_AND_MASK_DBG_WAKEUP		BIT(22)
63 #define PMSU_STATUS_AND_MASK_IRQ_MASK		BIT(24)
64 #define PMSU_STATUS_AND_MASK_FIQ_MASK		BIT(25)
65 
66 #define PMSU_EVENT_STATUS_AND_MASK(cpu)     ((cpu * 0x100) + 0x120)
67 #define PMSU_EVENT_STATUS_AND_MASK_DFS_DONE        BIT(1)
68 #define PMSU_EVENT_STATUS_AND_MASK_DFS_DONE_MASK   BIT(17)
69 
70 #define PMSU_BOOT_ADDR_REDIRECT_OFFSET(cpu) ((cpu * 0x100) + 0x124)
71 
72 /* PMSU fabric registers */
73 #define L2C_NFABRIC_PM_CTL		    0x4
74 #define L2C_NFABRIC_PM_CTL_PWR_DOWN		BIT(20)
75 
76 /* PMSU delay registers */
77 #define PMSU_POWERDOWN_DELAY		    0xF04
78 #define PMSU_POWERDOWN_DELAY_PMU		BIT(1)
79 #define PMSU_POWERDOWN_DELAY_MASK		0xFFFE
80 #define PMSU_DFLT_ARMADA38X_DELAY	        0x64
81 
82 /* CA9 MPcore SoC Control registers */
83 
84 #define MPCORE_RESET_CTL		    0x64
85 #define MPCORE_RESET_CTL_L2			BIT(0)
86 #define MPCORE_RESET_CTL_DEBUG			BIT(16)
87 
88 #define SRAM_PHYS_BASE  0xFFFF0000
89 #define BOOTROM_BASE    0xFFF00000
90 #define BOOTROM_SIZE    0x100000
91 
92 #define ARMADA_370_CRYPT0_ENG_TARGET   0x9
93 #define ARMADA_370_CRYPT0_ENG_ATTR     0x1
94 
95 extern void ll_disable_coherency(void);
96 extern void ll_enable_coherency(void);
97 
98 extern void armada_370_xp_cpu_resume(void);
99 extern void armada_38x_cpu_resume(void);
100 
101 static phys_addr_t pmsu_mp_phys_base;
102 static void __iomem *pmsu_mp_base;
103 
104 static void *mvebu_cpu_resume;
105 
106 static const struct of_device_id of_pmsu_table[] = {
107 	{ .compatible = "marvell,armada-370-pmsu", },
108 	{ .compatible = "marvell,armada-370-xp-pmsu", },
109 	{ .compatible = "marvell,armada-380-pmsu", },
110 	{ /* end of list */ },
111 };
112 
113 void mvebu_pmsu_set_cpu_boot_addr(int hw_cpu, void *boot_addr)
114 {
115 	writel(__pa_symbol(boot_addr), pmsu_mp_base +
116 		PMSU_BOOT_ADDR_REDIRECT_OFFSET(hw_cpu));
117 }
118 
119 extern unsigned char mvebu_boot_wa_start;
120 extern unsigned char mvebu_boot_wa_end;
121 
122 /*
123  * This function sets up the boot address workaround needed for SMP
124  * boot on Armada 375 Z1 and cpuidle on Armada 370. It unmaps the
125  * BootROM Mbus window, and instead remaps a crypto SRAM into which a
126  * custom piece of code is copied to replace the problematic BootROM.
127  */
128 int mvebu_setup_boot_addr_wa(unsigned int crypto_eng_target,
129 			     unsigned int crypto_eng_attribute,
130 			     phys_addr_t resume_addr_reg)
131 {
132 	void __iomem *sram_virt_base;
133 	u32 code_len = &mvebu_boot_wa_end - &mvebu_boot_wa_start;
134 
135 	mvebu_mbus_del_window(BOOTROM_BASE, BOOTROM_SIZE);
136 	mvebu_mbus_add_window_by_id(crypto_eng_target, crypto_eng_attribute,
137 				    SRAM_PHYS_BASE, SZ_64K);
138 
139 	sram_virt_base = ioremap(SRAM_PHYS_BASE, SZ_64K);
140 	if (!sram_virt_base) {
141 		pr_err("Unable to map SRAM to setup the boot address WA\n");
142 		return -ENOMEM;
143 	}
144 
145 	memcpy(sram_virt_base, &mvebu_boot_wa_start, code_len);
146 
147 	/*
148 	 * The last word of the code copied in SRAM must contain the
149 	 * physical base address of the PMSU register. We
150 	 * intentionally store this address in the native endianness
151 	 * of the system.
152 	 */
153 	__raw_writel((unsigned long)resume_addr_reg,
154 		     sram_virt_base + code_len - 4);
155 
156 	iounmap(sram_virt_base);
157 
158 	return 0;
159 }
160 
161 static int __init mvebu_v7_pmsu_init(void)
162 {
163 	struct device_node *np;
164 	struct resource res;
165 	int ret = 0;
166 
167 	np = of_find_matching_node(NULL, of_pmsu_table);
168 	if (!np)
169 		return 0;
170 
171 	pr_info("Initializing Power Management Service Unit\n");
172 
173 	if (of_address_to_resource(np, 0, &res)) {
174 		pr_err("unable to get resource\n");
175 		ret = -ENOENT;
176 		goto out;
177 	}
178 
179 	if (of_device_is_compatible(np, "marvell,armada-370-xp-pmsu")) {
180 		pr_warn(FW_WARN "deprecated pmsu binding\n");
181 		res.start = res.start - PMSU_BASE_OFFSET;
182 		res.end = res.start + PMSU_REG_SIZE - 1;
183 	}
184 
185 	if (!request_mem_region(res.start, resource_size(&res),
186 				np->full_name)) {
187 		pr_err("unable to request region\n");
188 		ret = -EBUSY;
189 		goto out;
190 	}
191 
192 	pmsu_mp_phys_base = res.start;
193 
194 	pmsu_mp_base = ioremap(res.start, resource_size(&res));
195 	if (!pmsu_mp_base) {
196 		pr_err("unable to map registers\n");
197 		release_mem_region(res.start, resource_size(&res));
198 		ret = -ENOMEM;
199 		goto out;
200 	}
201 
202  out:
203 	of_node_put(np);
204 	return ret;
205 }
206 
207 static void mvebu_v7_pmsu_enable_l2_powerdown_onidle(void)
208 {
209 	u32 reg;
210 
211 	if (pmsu_mp_base == NULL)
212 		return;
213 
214 	/* Enable L2 & Fabric powerdown in Deep-Idle mode - Fabric */
215 	reg = readl(pmsu_mp_base + L2C_NFABRIC_PM_CTL);
216 	reg |= L2C_NFABRIC_PM_CTL_PWR_DOWN;
217 	writel(reg, pmsu_mp_base + L2C_NFABRIC_PM_CTL);
218 }
219 
220 enum pmsu_idle_prepare_flags {
221 	PMSU_PREPARE_NORMAL = 0,
222 	PMSU_PREPARE_DEEP_IDLE = BIT(0),
223 	PMSU_PREPARE_SNOOP_DISABLE = BIT(1),
224 };
225 
226 /* No locking is needed because we only access per-CPU registers */
227 static int mvebu_v7_pmsu_idle_prepare(unsigned long flags)
228 {
229 	unsigned int hw_cpu = cpu_logical_map(smp_processor_id());
230 	u32 reg;
231 
232 	if (pmsu_mp_base == NULL)
233 		return -EINVAL;
234 
235 	/*
236 	 * Adjust the PMSU configuration to wait for WFI signal, enable
237 	 * IRQ and FIQ as wakeup events, set wait for snoop queue empty
238 	 * indication and mask IRQ and FIQ from CPU
239 	 */
240 	reg = readl(pmsu_mp_base + PMSU_STATUS_AND_MASK(hw_cpu));
241 	reg |= PMSU_STATUS_AND_MASK_CPU_IDLE_WAIT    |
242 	       PMSU_STATUS_AND_MASK_IRQ_WAKEUP       |
243 	       PMSU_STATUS_AND_MASK_FIQ_WAKEUP       |
244 	       PMSU_STATUS_AND_MASK_SNP_Q_EMPTY_WAIT |
245 	       PMSU_STATUS_AND_MASK_IRQ_MASK         |
246 	       PMSU_STATUS_AND_MASK_FIQ_MASK;
247 	writel(reg, pmsu_mp_base + PMSU_STATUS_AND_MASK(hw_cpu));
248 
249 	reg = readl(pmsu_mp_base + PMSU_CONTROL_AND_CONFIG(hw_cpu));
250 	/* ask HW to power down the L2 Cache if needed */
251 	if (flags & PMSU_PREPARE_DEEP_IDLE)
252 		reg |= PMSU_CONTROL_AND_CONFIG_L2_PWDDN;
253 
254 	/* request power down */
255 	reg |= PMSU_CONTROL_AND_CONFIG_PWDDN_REQ;
256 	writel(reg, pmsu_mp_base + PMSU_CONTROL_AND_CONFIG(hw_cpu));
257 
258 	if (flags & PMSU_PREPARE_SNOOP_DISABLE) {
259 		/* Disable snoop disable by HW - SW is taking care of it */
260 		reg = readl(pmsu_mp_base + PMSU_CPU_POWER_DOWN_CONTROL(hw_cpu));
261 		reg |= PMSU_CPU_POWER_DOWN_DIS_SNP_Q_SKIP;
262 		writel(reg, pmsu_mp_base + PMSU_CPU_POWER_DOWN_CONTROL(hw_cpu));
263 	}
264 
265 	return 0;
266 }
267 
268 int armada_370_xp_pmsu_idle_enter(unsigned long deepidle)
269 {
270 	unsigned long flags = PMSU_PREPARE_SNOOP_DISABLE;
271 	int ret;
272 
273 	if (deepidle)
274 		flags |= PMSU_PREPARE_DEEP_IDLE;
275 
276 	ret = mvebu_v7_pmsu_idle_prepare(flags);
277 	if (ret)
278 		return ret;
279 
280 	v7_exit_coherency_flush(all);
281 
282 	ll_disable_coherency();
283 
284 	dsb();
285 
286 	wfi();
287 
288 	/* If we are here, wfi failed. As processors run out of
289 	 * coherency for some time, tlbs might be stale, so flush them
290 	 */
291 	local_flush_tlb_all();
292 
293 	ll_enable_coherency();
294 
295 	/* Test the CR_C bit and set it if it was cleared */
296 	asm volatile(
297 	"mrc	p15, 0, r0, c1, c0, 0 \n\t"
298 	"tst	r0, %0 \n\t"
299 	"orreq	r0, r0, #(1 << 2) \n\t"
300 	"mcreq	p15, 0, r0, c1, c0, 0 \n\t"
301 	"isb	"
302 	: : "Ir" (CR_C) : "r0");
303 
304 	pr_debug("Failed to suspend the system\n");
305 
306 	return 0;
307 }
308 
309 static int armada_370_xp_cpu_suspend(unsigned long deepidle)
310 {
311 	return cpu_suspend(deepidle, armada_370_xp_pmsu_idle_enter);
312 }
313 
314 int armada_38x_do_cpu_suspend(unsigned long deepidle)
315 {
316 	unsigned long flags = 0;
317 
318 	if (deepidle)
319 		flags |= PMSU_PREPARE_DEEP_IDLE;
320 
321 	mvebu_v7_pmsu_idle_prepare(flags);
322 	/*
323 	 * Already flushed cache, but do it again as the outer cache
324 	 * functions dirty the cache with spinlocks
325 	 */
326 	v7_exit_coherency_flush(louis);
327 
328 	scu_power_mode(mvebu_get_scu_base(), SCU_PM_POWEROFF);
329 
330 	cpu_do_idle();
331 
332 	return 1;
333 }
334 
335 static int armada_38x_cpu_suspend(unsigned long deepidle)
336 {
337 	return cpu_suspend(false, armada_38x_do_cpu_suspend);
338 }
339 
340 /* No locking is needed because we only access per-CPU registers */
341 void mvebu_v7_pmsu_idle_exit(void)
342 {
343 	unsigned int hw_cpu = cpu_logical_map(smp_processor_id());
344 	u32 reg;
345 
346 	if (pmsu_mp_base == NULL)
347 		return;
348 	/* cancel ask HW to power down the L2 Cache if possible */
349 	reg = readl(pmsu_mp_base + PMSU_CONTROL_AND_CONFIG(hw_cpu));
350 	reg &= ~PMSU_CONTROL_AND_CONFIG_L2_PWDDN;
351 	writel(reg, pmsu_mp_base + PMSU_CONTROL_AND_CONFIG(hw_cpu));
352 
353 	/* cancel Enable wakeup events and mask interrupts */
354 	reg = readl(pmsu_mp_base + PMSU_STATUS_AND_MASK(hw_cpu));
355 	reg &= ~(PMSU_STATUS_AND_MASK_IRQ_WAKEUP | PMSU_STATUS_AND_MASK_FIQ_WAKEUP);
356 	reg &= ~PMSU_STATUS_AND_MASK_CPU_IDLE_WAIT;
357 	reg &= ~PMSU_STATUS_AND_MASK_SNP_Q_EMPTY_WAIT;
358 	reg &= ~(PMSU_STATUS_AND_MASK_IRQ_MASK | PMSU_STATUS_AND_MASK_FIQ_MASK);
359 	writel(reg, pmsu_mp_base + PMSU_STATUS_AND_MASK(hw_cpu));
360 }
361 
362 static int mvebu_v7_cpu_pm_notify(struct notifier_block *self,
363 				    unsigned long action, void *hcpu)
364 {
365 	if (action == CPU_PM_ENTER) {
366 		unsigned int hw_cpu = cpu_logical_map(smp_processor_id());
367 		mvebu_pmsu_set_cpu_boot_addr(hw_cpu, mvebu_cpu_resume);
368 	} else if (action == CPU_PM_EXIT) {
369 		mvebu_v7_pmsu_idle_exit();
370 	}
371 
372 	return NOTIFY_OK;
373 }
374 
375 static struct notifier_block mvebu_v7_cpu_pm_notifier = {
376 	.notifier_call = mvebu_v7_cpu_pm_notify,
377 };
378 
379 static struct platform_device mvebu_v7_cpuidle_device;
380 
381 static int broken_idle(struct device_node *np)
382 {
383 	if (of_property_read_bool(np, "broken-idle")) {
384 		pr_warn("CPU idle is currently broken: disabling\n");
385 		return 1;
386 	}
387 
388 	return 0;
389 }
390 
391 static __init int armada_370_cpuidle_init(void)
392 {
393 	struct device_node *np;
394 	phys_addr_t redirect_reg;
395 
396 	np = of_find_compatible_node(NULL, NULL, "marvell,coherency-fabric");
397 	if (!np)
398 		return -ENODEV;
399 
400 	if (broken_idle(np))
401 		goto end;
402 
403 	/*
404 	 * On Armada 370, there is "a slow exit process from the deep
405 	 * idle state due to heavy L1/L2 cache cleanup operations
406 	 * performed by the BootROM software". To avoid this, we
407 	 * replace the restart code of the bootrom by a a simple jump
408 	 * to the boot address. Then the code located at this boot
409 	 * address will take care of the initialization.
410 	 */
411 	redirect_reg = pmsu_mp_phys_base + PMSU_BOOT_ADDR_REDIRECT_OFFSET(0);
412 	mvebu_setup_boot_addr_wa(ARMADA_370_CRYPT0_ENG_TARGET,
413 				 ARMADA_370_CRYPT0_ENG_ATTR,
414 				 redirect_reg);
415 
416 	mvebu_cpu_resume = armada_370_xp_cpu_resume;
417 	mvebu_v7_cpuidle_device.dev.platform_data = armada_370_xp_cpu_suspend;
418 	mvebu_v7_cpuidle_device.name = "cpuidle-armada-370";
419 
420 end:
421 	of_node_put(np);
422 	return 0;
423 }
424 
425 static __init int armada_38x_cpuidle_init(void)
426 {
427 	struct device_node *np;
428 	void __iomem *mpsoc_base;
429 	u32 reg;
430 
431 	pr_warn("CPU idle is currently broken on Armada 38x: disabling\n");
432 	return 0;
433 
434 	np = of_find_compatible_node(NULL, NULL,
435 				     "marvell,armada-380-coherency-fabric");
436 	if (!np)
437 		return -ENODEV;
438 
439 	if (broken_idle(np))
440 		goto end;
441 
442 	of_node_put(np);
443 
444 	np = of_find_compatible_node(NULL, NULL,
445 				     "marvell,armada-380-mpcore-soc-ctrl");
446 	if (!np)
447 		return -ENODEV;
448 	mpsoc_base = of_iomap(np, 0);
449 	BUG_ON(!mpsoc_base);
450 
451 	/* Set up reset mask when powering down the cpus */
452 	reg = readl(mpsoc_base + MPCORE_RESET_CTL);
453 	reg |= MPCORE_RESET_CTL_L2;
454 	reg |= MPCORE_RESET_CTL_DEBUG;
455 	writel(reg, mpsoc_base + MPCORE_RESET_CTL);
456 	iounmap(mpsoc_base);
457 
458 	/* Set up delay */
459 	reg = readl(pmsu_mp_base + PMSU_POWERDOWN_DELAY);
460 	reg &= ~PMSU_POWERDOWN_DELAY_MASK;
461 	reg |= PMSU_DFLT_ARMADA38X_DELAY;
462 	reg |= PMSU_POWERDOWN_DELAY_PMU;
463 	writel(reg, pmsu_mp_base + PMSU_POWERDOWN_DELAY);
464 
465 	mvebu_cpu_resume = armada_38x_cpu_resume;
466 	mvebu_v7_cpuidle_device.dev.platform_data = armada_38x_cpu_suspend;
467 	mvebu_v7_cpuidle_device.name = "cpuidle-armada-38x";
468 
469 end:
470 	of_node_put(np);
471 	return 0;
472 }
473 
474 static __init int armada_xp_cpuidle_init(void)
475 {
476 	struct device_node *np;
477 
478 	np = of_find_compatible_node(NULL, NULL, "marvell,coherency-fabric");
479 	if (!np)
480 		return -ENODEV;
481 
482 	if (broken_idle(np))
483 		goto end;
484 
485 	mvebu_cpu_resume = armada_370_xp_cpu_resume;
486 	mvebu_v7_cpuidle_device.dev.platform_data = armada_370_xp_cpu_suspend;
487 	mvebu_v7_cpuidle_device.name = "cpuidle-armada-xp";
488 
489 end:
490 	of_node_put(np);
491 	return 0;
492 }
493 
494 static int __init mvebu_v7_cpu_pm_init(void)
495 {
496 	struct device_node *np;
497 	int ret;
498 
499 	np = of_find_matching_node(NULL, of_pmsu_table);
500 	if (!np)
501 		return 0;
502 	of_node_put(np);
503 
504 	/*
505 	 * Currently the CPU idle support for Armada 38x is broken, as
506 	 * the CPU hotplug uses some of the CPU idle functions it is
507 	 * broken too, so let's disable it
508 	 */
509 	if (of_machine_is_compatible("marvell,armada380")) {
510 		cpu_hotplug_disable();
511 		pr_warn("CPU hotplug support is currently broken on Armada 38x: disabling\n");
512 	}
513 
514 	if (of_machine_is_compatible("marvell,armadaxp"))
515 		ret = armada_xp_cpuidle_init();
516 	else if (of_machine_is_compatible("marvell,armada370"))
517 		ret = armada_370_cpuidle_init();
518 	else if (of_machine_is_compatible("marvell,armada380"))
519 		ret = armada_38x_cpuidle_init();
520 	else
521 		return 0;
522 
523 	if (ret)
524 		return ret;
525 
526 	mvebu_v7_pmsu_enable_l2_powerdown_onidle();
527 	if (mvebu_v7_cpuidle_device.name)
528 		platform_device_register(&mvebu_v7_cpuidle_device);
529 	cpu_pm_register_notifier(&mvebu_v7_cpu_pm_notifier);
530 
531 	return 0;
532 }
533 
534 arch_initcall(mvebu_v7_cpu_pm_init);
535 early_initcall(mvebu_v7_pmsu_init);
536 
537 static void mvebu_pmsu_dfs_request_local(void *data)
538 {
539 	u32 reg;
540 	u32 cpu = smp_processor_id();
541 	unsigned long flags;
542 
543 	local_irq_save(flags);
544 
545 	/* Prepare to enter idle */
546 	reg = readl(pmsu_mp_base + PMSU_STATUS_AND_MASK(cpu));
547 	reg |= PMSU_STATUS_AND_MASK_CPU_IDLE_WAIT |
548 	       PMSU_STATUS_AND_MASK_IRQ_MASK     |
549 	       PMSU_STATUS_AND_MASK_FIQ_MASK;
550 	writel(reg, pmsu_mp_base + PMSU_STATUS_AND_MASK(cpu));
551 
552 	/* Request the DFS transition */
553 	reg = readl(pmsu_mp_base + PMSU_CONTROL_AND_CONFIG(cpu));
554 	reg |= PMSU_CONTROL_AND_CONFIG_DFS_REQ;
555 	writel(reg, pmsu_mp_base + PMSU_CONTROL_AND_CONFIG(cpu));
556 
557 	/* The fact of entering idle will trigger the DFS transition */
558 	wfi();
559 
560 	/*
561 	 * We're back from idle, the DFS transition has completed,
562 	 * clear the idle wait indication.
563 	 */
564 	reg = readl(pmsu_mp_base + PMSU_STATUS_AND_MASK(cpu));
565 	reg &= ~PMSU_STATUS_AND_MASK_CPU_IDLE_WAIT;
566 	writel(reg, pmsu_mp_base + PMSU_STATUS_AND_MASK(cpu));
567 
568 	local_irq_restore(flags);
569 }
570 
571 int mvebu_pmsu_dfs_request(int cpu)
572 {
573 	unsigned long timeout;
574 	int hwcpu = cpu_logical_map(cpu);
575 	u32 reg;
576 
577 	/* Clear any previous DFS DONE event */
578 	reg = readl(pmsu_mp_base + PMSU_EVENT_STATUS_AND_MASK(hwcpu));
579 	reg &= ~PMSU_EVENT_STATUS_AND_MASK_DFS_DONE;
580 	writel(reg, pmsu_mp_base + PMSU_EVENT_STATUS_AND_MASK(hwcpu));
581 
582 	/* Mask the DFS done interrupt, since we are going to poll */
583 	reg = readl(pmsu_mp_base + PMSU_EVENT_STATUS_AND_MASK(hwcpu));
584 	reg |= PMSU_EVENT_STATUS_AND_MASK_DFS_DONE_MASK;
585 	writel(reg, pmsu_mp_base + PMSU_EVENT_STATUS_AND_MASK(hwcpu));
586 
587 	/* Trigger the DFS on the appropriate CPU */
588 	smp_call_function_single(cpu, mvebu_pmsu_dfs_request_local,
589 				 NULL, false);
590 
591 	/* Poll until the DFS done event is generated */
592 	timeout = jiffies + HZ;
593 	while (time_before(jiffies, timeout)) {
594 		reg = readl(pmsu_mp_base + PMSU_EVENT_STATUS_AND_MASK(hwcpu));
595 		if (reg & PMSU_EVENT_STATUS_AND_MASK_DFS_DONE)
596 			break;
597 		udelay(10);
598 	}
599 
600 	if (time_after(jiffies, timeout))
601 		return -ETIME;
602 
603 	/* Restore the DFS mask to its original state */
604 	reg = readl(pmsu_mp_base + PMSU_EVENT_STATUS_AND_MASK(hwcpu));
605 	reg &= ~PMSU_EVENT_STATUS_AND_MASK_DFS_DONE_MASK;
606 	writel(reg, pmsu_mp_base + PMSU_EVENT_STATUS_AND_MASK(hwcpu));
607 
608 	return 0;
609 }
610