1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Low-level power-management support for Alpine platform.
4  *
5  * Copyright (C) 2015 Annapurna Labs Ltd.
6  */
7 
8 #include <linux/io.h>
9 #include <linux/of.h>
10 #include <linux/of_address.h>
11 #include <linux/regmap.h>
12 #include <linux/mfd/syscon.h>
13 
14 #include "alpine_cpu_pm.h"
15 #include "alpine_cpu_resume.h"
16 
17 /* NB registers */
18 #define AL_SYSFAB_POWER_CONTROL(cpu)	(0x2000 + (cpu)*0x100 + 0x20)
19 
20 static struct regmap *al_sysfabric;
21 static struct al_cpu_resume_regs __iomem *al_cpu_resume_regs;
22 static int wakeup_supported;
23 
24 int alpine_cpu_wakeup(unsigned int phys_cpu, uint32_t phys_resume_addr)
25 {
26 	if (!wakeup_supported)
27 		return -ENOSYS;
28 
29 	/*
30 	 * Set CPU resume address -
31 	 * secure firmware running on boot will jump to this address
32 	 * after setting proper CPU mode, and initialiing e.g. secure
33 	 * regs (the same mode all CPUs are booted to - usually HYP)
34 	 */
35 	writel(phys_resume_addr,
36 	       &al_cpu_resume_regs->per_cpu[phys_cpu].resume_addr);
37 
38 	/* Power-up the CPU */
39 	regmap_write(al_sysfabric, AL_SYSFAB_POWER_CONTROL(phys_cpu), 0);
40 
41 	return 0;
42 }
43 
44 void __init alpine_cpu_pm_init(void)
45 {
46 	struct device_node *np;
47 	uint32_t watermark;
48 
49 	al_sysfabric = syscon_regmap_lookup_by_compatible("al,alpine-sysfabric-service");
50 
51 	np = of_find_compatible_node(NULL, NULL, "al,alpine-cpu-resume");
52 	al_cpu_resume_regs = of_iomap(np, 0);
53 
54 	wakeup_supported = !IS_ERR(al_sysfabric) && al_cpu_resume_regs;
55 
56 	if (wakeup_supported) {
57 		watermark = readl(&al_cpu_resume_regs->watermark);
58 		wakeup_supported = (watermark & AL_CPU_RESUME_MAGIC_NUM_MASK)
59 				    == AL_CPU_RESUME_MAGIC_NUM;
60 	}
61 }
62