278 lines
7.0 KiB
C
278 lines
7.0 KiB
C
/*
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* arch/arm/mach-vexpress/tc2_pm.c - TC2 power management support
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*
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* Created by: Nicolas Pitre, October 2012
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* Copyright: (C) 2012 Linaro Limited
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*
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* Some portions of this file were originally written by Achin Gupta
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* Copyright: (C) 2012 ARM 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 <linux/irqchip/arm-gic.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/cputype.h>
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#include <asm/cp15.h>
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#include <asm/psci.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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#include <linux/arm-cci.h>
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/*
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* We can't use regular spinlocks. In the switcher case, it is possible
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* for an outbound CPU to call power_down() after its inbound counterpart
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* is already live using the same logical CPU number which trips lockdep
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* debugging.
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*/
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static arch_spinlock_t tc2_pm_lock = __ARCH_SPIN_LOCK_UNLOCKED;
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static int tc2_pm_use_count[TC2_MAX_CPUS][TC2_MAX_CLUSTERS];
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static int tc2_pm_power_up(unsigned int cpu, unsigned int cluster)
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{
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pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
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if (cluster >= TC2_MAX_CLUSTERS ||
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cpu >= vexpress_spc_get_nb_cpus(cluster))
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return -EINVAL;
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/*
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* Since this is called with IRQs enabled, and no arch_spin_lock_irq
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* variant exists, we need to disable IRQs manually here.
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*/
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local_irq_disable();
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arch_spin_lock(&tc2_pm_lock);
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if (!tc2_pm_use_count[0][cluster] &&
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!tc2_pm_use_count[1][cluster] &&
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!tc2_pm_use_count[2][cluster])
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vexpress_spc_powerdown_enable(cluster, 0);
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tc2_pm_use_count[cpu][cluster]++;
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if (tc2_pm_use_count[cpu][cluster] == 1) {
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vexpress_spc_write_resume_reg(cluster, cpu,
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virt_to_phys(mcpm_entry_point));
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vexpress_spc_set_cpu_wakeup_irq(cpu, cluster, 1);
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} else if (tc2_pm_use_count[cpu][cluster] != 2) {
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/*
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* The only possible values are:
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* 0 = CPU down
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* 1 = CPU (still) up
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* 2 = CPU requested to be up before it had a chance
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* to actually make itself down.
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* Any other value is a bug.
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*/
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BUG();
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}
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arch_spin_unlock(&tc2_pm_lock);
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local_irq_enable();
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return 0;
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}
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static void tc2_pm_down(u64 residency)
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{
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unsigned int mpidr, cpu, cluster;
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bool last_man = false, skip_wfi = false;
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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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__mcpm_cpu_going_down(cpu, cluster);
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arch_spin_lock(&tc2_pm_lock);
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BUG_ON(__mcpm_cluster_state(cluster) != CLUSTER_UP);
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tc2_pm_use_count[cpu][cluster]--;
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if (tc2_pm_use_count[cpu][cluster] == 0) {
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vexpress_spc_set_cpu_wakeup_irq(cpu, cluster, 1);
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if (!tc2_pm_use_count[0][cluster] &&
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!tc2_pm_use_count[1][cluster] &&
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!tc2_pm_use_count[2][cluster] &&
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(!residency || residency > 5000)) {
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vexpress_spc_powerdown_enable(cluster, 1);
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vexpress_spc_set_global_wakeup_intr(1);
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last_man = true;
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}
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} else if (tc2_pm_use_count[cpu][cluster] == 1) {
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/*
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* A power_up request went ahead of us.
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* Even if we do not want to shut this CPU down,
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* the caller expects a certain state as if the WFI
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* was aborted. So let's continue with cache cleaning.
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*/
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skip_wfi = true;
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} else
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BUG();
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/*
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* If the CPU is committed to power down, make sure
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* the power controller will be in charge of waking it
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* up upon IRQ, ie IRQ lines are cut from GIC CPU IF
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* to the CPU by disabling the GIC CPU IF to prevent wfi
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* from completing execution behind power controller back
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*/
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if (!skip_wfi)
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gic_cpu_if_down();
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if (last_man && __mcpm_outbound_enter_critical(cpu, cluster)) {
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arch_spin_unlock(&tc2_pm_lock);
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if (read_cpuid_part_number() == ARM_CPU_PART_CORTEX_A15) {
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/*
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* On the Cortex-A15 we need to disable
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* L2 prefetching before flushing the cache.
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*/
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asm volatile(
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"mcr p15, 1, %0, c15, c0, 3 \n\t"
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"isb \n\t"
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"dsb "
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: : "r" (0x400) );
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}
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v7_exit_coherency_flush(all);
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cci_disable_port_by_cpu(mpidr);
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__mcpm_outbound_leave_critical(cluster, CLUSTER_DOWN);
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} else {
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/*
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* If last man then undo any setup done previously.
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*/
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if (last_man) {
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vexpress_spc_powerdown_enable(cluster, 0);
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vexpress_spc_set_global_wakeup_intr(0);
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}
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arch_spin_unlock(&tc2_pm_lock);
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v7_exit_coherency_flush(louis);
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}
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__mcpm_cpu_down(cpu, cluster);
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/* Now we are prepared for power-down, do it: */
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if (!skip_wfi)
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wfi();
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/* Not dead at this point? Let our caller cope. */
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}
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static void tc2_pm_power_down(void)
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{
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tc2_pm_down(0);
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}
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static void tc2_pm_suspend(u64 residency)
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{
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extern void tc2_resume(void);
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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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vexpress_spc_write_resume_reg(cluster, cpu,
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virt_to_phys(tc2_resume));
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tc2_pm_down(residency);
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}
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static void tc2_pm_powered_up(void)
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{
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unsigned int mpidr, cpu, cluster;
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unsigned long flags;
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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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local_irq_save(flags);
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arch_spin_lock(&tc2_pm_lock);
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if (!tc2_pm_use_count[0][cluster] &&
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!tc2_pm_use_count[1][cluster] &&
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!tc2_pm_use_count[2][cluster]) {
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vexpress_spc_powerdown_enable(cluster, 0);
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vexpress_spc_set_global_wakeup_intr(0);
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}
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if (!tc2_pm_use_count[cpu][cluster])
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tc2_pm_use_count[cpu][cluster] = 1;
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vexpress_spc_set_cpu_wakeup_irq(cpu, cluster, 0);
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vexpress_spc_write_resume_reg(cluster, cpu, 0);
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arch_spin_unlock(&tc2_pm_lock);
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local_irq_restore(flags);
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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_power_up,
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.power_down = tc2_pm_power_down,
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.suspend = tc2_pm_suspend,
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.powered_up = tc2_pm_powered_up,
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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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tc2_pm_use_count[cpu][cluster] = 1;
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}
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extern void tc2_pm_power_up_setup(unsigned int affinity_level);
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static int __init tc2_pm_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 found. Aborting native 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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return -ENODEV;
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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(tc2_pm_power_up_setup);
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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_init);
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