arch/arm/mach-alpine/alpine_cpu_pm.c

   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 }