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