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 
29 static struct regmap *al_sysfabric;
30 static struct al_cpu_resume_regs __iomem *al_cpu_resume_regs;
31 static int wakeup_supported;
32 
33 int 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 
53 void __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