| /* |
| * arch/arm/mach-vexpress/tc2_pm_psci.c - TC2 PSCI support |
| * |
| * Created by: Achin Gupta, December 2012 |
| * Copyright: (C) 2012 ARM Limited |
| * |
| * Some portions of this file were originally written by Nicolas Pitre |
| * Copyright: (C) 2012 Linaro Limited |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| */ |
| |
| #include <linux/init.h> |
| #include <linux/kernel.h> |
| #include <linux/of.h> |
| #include <linux/spinlock.h> |
| #include <linux/errno.h> |
| |
| #include <asm/mcpm.h> |
| #include <asm/proc-fns.h> |
| #include <asm/cacheflush.h> |
| #include <asm/psci.h> |
| #include <asm/atomic.h> |
| #include <asm/cputype.h> |
| #include <asm/cp15.h> |
| |
| #include <mach/motherboard.h> |
| |
| #include <linux/vexpress.h> |
| |
| /* |
| * Platform specific state id understood by the firmware and used to |
| * program the power controller |
| */ |
| #define PSCI_POWER_STATE_ID 0 |
| |
| #define TC2_CLUSTERS 2 |
| #define TC2_MAX_CPUS_PER_CLUSTER 3 |
| |
| static atomic_t tc2_pm_use_count[TC2_MAX_CPUS_PER_CLUSTER][TC2_CLUSTERS]; |
| |
| static int tc2_pm_psci_power_up(unsigned int cpu, unsigned int cluster) |
| { |
| unsigned int mpidr = (cluster << 8) | cpu; |
| int ret = 0; |
| |
| BUG_ON(!psci_ops.cpu_on); |
| |
| switch (atomic_inc_return(&tc2_pm_use_count[cpu][cluster])) { |
| case 1: |
| /* |
| * This is a request to power up a cpu that linux thinks has |
| * been powered down. Retries are needed if the firmware has |
| * seen the power down request as yet. |
| */ |
| do |
| ret = psci_ops.cpu_on(mpidr, |
| virt_to_phys(mcpm_entry_point)); |
| while (ret == -EAGAIN); |
| |
| return ret; |
| case 2: |
| /* This power up request has overtaken a power down request */ |
| return ret; |
| default: |
| /* Any other value is a bug */ |
| BUG(); |
| } |
| } |
| |
| static void tc2_pm_psci_power_down(void) |
| { |
| struct psci_power_state power_state; |
| unsigned int mpidr, cpu, cluster; |
| |
| mpidr = read_cpuid_mpidr(); |
| cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0); |
| cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1); |
| |
| BUG_ON(!psci_ops.cpu_off); |
| |
| switch (atomic_dec_return(&tc2_pm_use_count[cpu][cluster])) { |
| case 1: |
| /* |
| * Overtaken by a power up. Flush caches, exit coherency, |
| * return & fake a reset |
| */ |
| set_cr(get_cr() & ~CR_C); |
| |
| flush_cache_louis(); |
| |
| asm volatile ("clrex"); |
| set_auxcr(get_auxcr() & ~(1 << 6)); |
| |
| return; |
| case 0: |
| /* A normal request to possibly power down the cluster */ |
| power_state.id = PSCI_POWER_STATE_ID; |
| power_state.type = PSCI_POWER_STATE_TYPE_POWER_DOWN; |
| power_state.affinity_level = PSCI_POWER_STATE_AFFINITY_LEVEL1; |
| |
| psci_ops.cpu_off(power_state); |
| |
| /* On success this function never returns */ |
| default: |
| /* Any other value is a bug */ |
| BUG(); |
| } |
| } |
| |
| static void tc2_pm_psci_suspend(u64 unused) |
| { |
| struct psci_power_state power_state; |
| |
| BUG_ON(!psci_ops.cpu_suspend); |
| |
| /* On TC2 always attempt to power down the cluster */ |
| power_state.id = PSCI_POWER_STATE_ID; |
| power_state.type = PSCI_POWER_STATE_TYPE_POWER_DOWN; |
| power_state.affinity_level = PSCI_POWER_STATE_AFFINITY_LEVEL1; |
| |
| psci_ops.cpu_suspend(power_state, virt_to_phys(mcpm_entry_point)); |
| |
| /* On success this function never returns */ |
| BUG(); |
| } |
| |
| static const struct mcpm_platform_ops tc2_pm_power_ops = { |
| .power_up = tc2_pm_psci_power_up, |
| .power_down = tc2_pm_psci_power_down, |
| .suspend = tc2_pm_psci_suspend, |
| }; |
| |
| static void __init tc2_pm_usage_count_init(void) |
| { |
| unsigned int mpidr, cpu, cluster; |
| |
| mpidr = read_cpuid_mpidr(); |
| cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0); |
| cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1); |
| |
| pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster); |
| BUG_ON(cluster >= TC2_CLUSTERS || cpu >= TC2_MAX_CPUS_PER_CLUSTER); |
| |
| atomic_set(&tc2_pm_use_count[cpu][cluster], 1); |
| } |
| |
| static int __init tc2_pm_psci_init(void) |
| { |
| int ret; |
| |
| ret = psci_probe(); |
| if (ret) { |
| pr_debug("psci not found. Aborting psci init\n"); |
| return -ENODEV; |
| } |
| |
| if (!of_machine_is_compatible("arm,vexpress,v2p-ca15_a7")) |
| return -ENODEV; |
| |
| tc2_pm_usage_count_init(); |
| |
| ret = mcpm_platform_register(&tc2_pm_power_ops); |
| if (!ret) |
| ret = mcpm_sync_init(NULL); |
| if (!ret) |
| pr_info("TC2 power management using PSCI initialized\n"); |
| return ret; |
| } |
| |
| early_initcall(tc2_pm_psci_init); |