1/*
2 * Low-level power-management support for Alpine platform.
3 *
4 * Copyright (C) 2015 Annapurna Labs Ltd.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14 * GNU General Public License for more details.
15 */
16
17#include <linux/io.h>
18#include <linux/of.h>
19#include <linux/of_address.h>
20#include <linux/regmap.h>
21#include <linux/mfd/syscon.h>
22
23#include "alpine_cpu_pm.h"
24#include "alpine_cpu_resume.h"
25
26/* NB registers */
27#define AL_SYSFAB_POWER_CONTROL(cpu)	(0x2000 + (cpu)*0x100 + 0x20)
28
29static struct regmap *al_sysfabric;
30static struct al_cpu_resume_regs __iomem *al_cpu_resume_regs;
31static int wakeup_supported;
32
33int alpine_cpu_wakeup(unsigned int phys_cpu, uint32_t phys_resume_addr)
34{
35	if (!wakeup_supported)
36		return -ENOSYS;
37
38	/*
39	 * Set CPU resume address -
40	 * secure firmware running on boot will jump to this address
41	 * after setting proper CPU mode, and initialiing e.g. secure
42	 * regs (the same mode all CPUs are booted to - usually HYP)
43	 */
44	writel(phys_resume_addr,
45	       &al_cpu_resume_regs->per_cpu[phys_cpu].resume_addr);
46
47	/* Power-up the CPU */
48	regmap_write(al_sysfabric, AL_SYSFAB_POWER_CONTROL(phys_cpu), 0);
49
50	return 0;
51}
52
53void __init alpine_cpu_pm_init(void)
54{
55	struct device_node *np;
56	uint32_t watermark;
57
58	al_sysfabric = syscon_regmap_lookup_by_compatible("al,alpine-sysfabric-service");
59
60	np = of_find_compatible_node(NULL, NULL, "al,alpine-cpu-resume");
61	al_cpu_resume_regs = of_iomap(np, 0);
62
63	wakeup_supported = !IS_ERR(al_sysfabric) && al_cpu_resume_regs;
64
65	if (wakeup_supported) {
66		watermark = readl(&al_cpu_resume_regs->watermark);
67		wakeup_supported = (watermark & AL_CPU_RESUME_MAGIC_NUM_MASK)
68				    == AL_CPU_RESUME_MAGIC_NUM;
69	}
70}
71