LXR linux/arch/arm/mach-alpine/alpine_cpu

   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