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 initializing 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
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