u-boot/arch/arm/mach-tegra/tegra124/psci.c

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/*
* (C) Copyright 2015, Siemens AG
* Author: Jan Kiszka <jan.kiszka@siemens.com>
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <asm/io.h>
#include <asm/psci.h>
#include <asm/arch/flow.h>
#include <asm/arch/powergate.h>
#include <asm/arch-tegra/ap.h>
#include <asm/arch-tegra/pmc.h>
static void park_cpu(void)
{
while (1)
asm volatile("wfi");
}
/**
* Initialize power management for application processors
*/
void psci_board_init(void)
{
struct flow_ctlr *flow = (struct flow_ctlr *)NV_PA_FLOW_BASE;
writel((u32)park_cpu, EXCEP_VECTOR_CPU_RESET_VECTOR);
/*
* The naturally expected order of putting these CPUs under Flow
* Controller regime would be
* - configure the Flow Controller
* - power up the CPUs
* - wait for the CPUs to hit wfi and be powered down again
*
* However, this doesn't work in practice. We rather need to power them
* up first and park them in wfi. While they are waiting there, we can
* indeed program the Flow Controller to powergate them on wfi, which
* will then happen immediately as they are already in that state.
*/
tegra_powergate_power_on(TEGRA_POWERGATE_CPU1);
tegra_powergate_power_on(TEGRA_POWERGATE_CPU2);
tegra_powergate_power_on(TEGRA_POWERGATE_CPU3);
writel((2 << CSR_WAIT_WFI_SHIFT) | CSR_ENABLE, &flow->cpu1_csr);
writel((4 << CSR_WAIT_WFI_SHIFT) | CSR_ENABLE, &flow->cpu2_csr);
writel((8 << CSR_WAIT_WFI_SHIFT) | CSR_ENABLE, &flow->cpu3_csr);
writel(EVENT_MODE_STOP, &flow->halt_cpu1_events);
writel(EVENT_MODE_STOP, &flow->halt_cpu2_events);
writel(EVENT_MODE_STOP, &flow->halt_cpu3_events);
while (!(readl(&flow->cpu1_csr) & CSR_PWR_OFF_STS) ||
!(readl(&flow->cpu2_csr) & CSR_PWR_OFF_STS) ||
!(readl(&flow->cpu3_csr) & CSR_PWR_OFF_STS))
/* wait */;
}