1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * (C) Copyright 2015, Siemens AG 4 * Author: Jan Kiszka <jan.kiszka@siemens.com> 5 */ 6 7 #include <common.h> 8 #include <asm/io.h> 9 #include <asm/psci.h> 10 #include <asm/arch/flow.h> 11 #include <asm/arch/powergate.h> 12 #include <asm/arch-tegra/ap.h> 13 #include <asm/arch-tegra/pmc.h> 14 15 static void park_cpu(void) 16 { 17 while (1) 18 asm volatile("wfi"); 19 } 20 21 /** 22 * Initialize power management for application processors 23 */ 24 void psci_board_init(void) 25 { 26 struct flow_ctlr *flow = (struct flow_ctlr *)NV_PA_FLOW_BASE; 27 28 writel((u32)park_cpu, EXCEP_VECTOR_CPU_RESET_VECTOR); 29 30 /* 31 * The naturally expected order of putting these CPUs under Flow 32 * Controller regime would be 33 * - configure the Flow Controller 34 * - power up the CPUs 35 * - wait for the CPUs to hit wfi and be powered down again 36 * 37 * However, this doesn't work in practice. We rather need to power them 38 * up first and park them in wfi. While they are waiting there, we can 39 * indeed program the Flow Controller to powergate them on wfi, which 40 * will then happen immediately as they are already in that state. 41 */ 42 tegra_powergate_power_on(TEGRA_POWERGATE_CPU1); 43 tegra_powergate_power_on(TEGRA_POWERGATE_CPU2); 44 tegra_powergate_power_on(TEGRA_POWERGATE_CPU3); 45 46 writel((2 << CSR_WAIT_WFI_SHIFT) | CSR_ENABLE, &flow->cpu1_csr); 47 writel((4 << CSR_WAIT_WFI_SHIFT) | CSR_ENABLE, &flow->cpu2_csr); 48 writel((8 << CSR_WAIT_WFI_SHIFT) | CSR_ENABLE, &flow->cpu3_csr); 49 50 writel(EVENT_MODE_STOP, &flow->halt_cpu1_events); 51 writel(EVENT_MODE_STOP, &flow->halt_cpu2_events); 52 writel(EVENT_MODE_STOP, &flow->halt_cpu3_events); 53 54 while (!(readl(&flow->cpu1_csr) & CSR_PWR_OFF_STS) || 55 !(readl(&flow->cpu2_csr) & CSR_PWR_OFF_STS) || 56 !(readl(&flow->cpu3_csr) & CSR_PWR_OFF_STS)) 57 /* wait */; 58 } 59