174 lines
4.1 KiB
C
174 lines
4.1 KiB
C
/*
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* arch/arm/mach-vexpress/tc2_pm_psci.c - TC2 PSCI support
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*
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* Created by: Achin Gupta, December 2012
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* Copyright: (C) 2012 ARM Limited
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*
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* Some portions of this file were originally written by Nicolas Pitre
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* Copyright: (C) 2012 Linaro Limited
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/spinlock.h>
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#include <linux/errno.h>
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#include <asm/mcpm.h>
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#include <asm/proc-fns.h>
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#include <asm/cacheflush.h>
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#include <asm/psci.h>
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#include <asm/atomic.h>
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#include <asm/cputype.h>
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#include <asm/cp15.h>
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#include <mach/motherboard.h>
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#include <mach/tc2.h>
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#include <linux/vexpress.h>
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/*
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* Platform specific state id understood by the firmware and used to
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* program the power controller
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*/
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#define PSCI_POWER_STATE_ID 0
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static atomic_t tc2_pm_use_count[TC2_MAX_CPUS][TC2_MAX_CLUSTERS];
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static int tc2_pm_psci_power_up(unsigned int cpu, unsigned int cluster)
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{
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unsigned int mpidr = (cluster << 8) | cpu;
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int ret = 0;
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BUG_ON(!psci_ops.cpu_on);
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switch (atomic_inc_return(&tc2_pm_use_count[cpu][cluster])) {
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case 1:
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/*
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* This is a request to power up a cpu that linux thinks has
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* been powered down. Retries are needed if the firmware has
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* seen the power down request as yet.
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*/
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do
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ret = psci_ops.cpu_on(mpidr,
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virt_to_phys(mcpm_entry_point));
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while (ret == -EAGAIN);
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return ret;
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case 2:
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/* This power up request has overtaken a power down request */
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return ret;
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default:
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/* Any other value is a bug */
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BUG();
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}
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}
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static void tc2_pm_psci_power_down(void)
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{
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struct psci_power_state power_state;
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unsigned int mpidr, cpu, cluster;
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mpidr = read_cpuid_mpidr();
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cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
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cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
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BUG_ON(!psci_ops.cpu_off);
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switch (atomic_dec_return(&tc2_pm_use_count[cpu][cluster])) {
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case 1:
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/*
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* Overtaken by a power up. Flush caches, exit coherency,
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* return & fake a reset
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*/
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set_cr(get_cr() & ~CR_C);
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flush_cache_louis();
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asm volatile ("clrex");
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set_auxcr(get_auxcr() & ~(1 << 6));
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return;
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case 0:
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/* A normal request to possibly power down the cluster */
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power_state.id = PSCI_POWER_STATE_ID;
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power_state.type = PSCI_POWER_STATE_TYPE_POWER_DOWN;
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power_state.affinity_level = PSCI_POWER_STATE_AFFINITY_LEVEL1;
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psci_ops.cpu_off(power_state);
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/* On success this function never returns */
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default:
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/* Any other value is a bug */
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BUG();
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}
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}
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static void tc2_pm_psci_suspend(u64 unused)
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{
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struct psci_power_state power_state;
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BUG_ON(!psci_ops.cpu_suspend);
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/* On TC2 always attempt to power down the cluster */
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power_state.id = PSCI_POWER_STATE_ID;
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power_state.type = PSCI_POWER_STATE_TYPE_POWER_DOWN;
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power_state.affinity_level = PSCI_POWER_STATE_AFFINITY_LEVEL1;
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psci_ops.cpu_suspend(power_state, virt_to_phys(mcpm_entry_point));
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/* On success this function never returns */
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BUG();
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}
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static const struct mcpm_platform_ops tc2_pm_power_ops = {
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.power_up = tc2_pm_psci_power_up,
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.power_down = tc2_pm_psci_power_down,
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.suspend = tc2_pm_psci_suspend,
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};
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static void __init tc2_pm_usage_count_init(void)
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{
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unsigned int mpidr, cpu, cluster;
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mpidr = read_cpuid_mpidr();
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cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
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cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
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pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
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BUG_ON(cluster >= TC2_MAX_CLUSTERS ||
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cpu >= vexpress_spc_get_nb_cpus(cluster));
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atomic_set(&tc2_pm_use_count[cpu][cluster], 1);
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}
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static int __init tc2_pm_psci_init(void)
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{
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int ret;
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ret = psci_probe();
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if (ret) {
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pr_debug("psci not found. Aborting psci init\n");
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return -ENODEV;
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}
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if (!vexpress_spc_check_loaded()) {
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pr_debug("spc not found. Aborting psci init\n");
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return -ENODEV;
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}
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tc2_pm_usage_count_init();
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ret = mcpm_platform_register(&tc2_pm_power_ops);
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if (!ret)
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ret = mcpm_sync_init(NULL);
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if (!ret)
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pr_info("TC2 power management initialized\n");
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return ret;
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}
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early_initcall(tc2_pm_psci_init);
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