| /* |
| * arch/arm/mach-vexpress/tc2_pm.c - TC2 power management support |
| * |
| * Created by: Nicolas Pitre, October 2012 |
| * Copyright: (C) 2012-2013 Linaro Limited |
| * |
| * Some portions of this file were originally written by Achin Gupta |
| * Copyright: (C) 2012 ARM 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/delay.h> |
| #include <linux/init.h> |
| #include <linux/io.h> |
| #include <linux/kernel.h> |
| #include <linux/of_address.h> |
| #include <linux/of_irq.h> |
| #include <linux/spinlock.h> |
| #include <linux/errno.h> |
| #include <linux/irqchip/arm-gic.h> |
| |
| #include <asm/mcpm.h> |
| #include <asm/proc-fns.h> |
| #include <asm/cacheflush.h> |
| #include <asm/cputype.h> |
| #include <asm/cp15.h> |
| |
| #include <linux/arm-cci.h> |
| |
| #include "spc.h" |
| |
| /* SCC conf registers */ |
| #define RESET_CTRL 0x018 |
| #define RESET_A15_NCORERESET(cpu) (1 << (2 + (cpu))) |
| #define RESET_A7_NCORERESET(cpu) (1 << (16 + (cpu))) |
| |
| #define A15_CONF 0x400 |
| #define A7_CONF 0x500 |
| #define SYS_INFO 0x700 |
| #define SPC_BASE 0xb00 |
| |
| static void __iomem *scc; |
| |
| /* |
| * We can't use regular spinlocks. In the switcher case, it is possible |
| * for an outbound CPU to call power_down() after its inbound counterpart |
| * is already live using the same logical CPU number which trips lockdep |
| * debugging. |
| */ |
| static arch_spinlock_t tc2_pm_lock = __ARCH_SPIN_LOCK_UNLOCKED; |
| |
| #define TC2_CLUSTERS 2 |
| #define TC2_MAX_CPUS_PER_CLUSTER 3 |
| |
| static unsigned int tc2_nr_cpus[TC2_CLUSTERS]; |
| |
| /* Keep per-cpu usage count to cope with unordered up/down requests */ |
| static int tc2_pm_use_count[TC2_MAX_CPUS_PER_CLUSTER][TC2_CLUSTERS]; |
| |
| #define tc2_cluster_unused(cluster) \ |
| (!tc2_pm_use_count[0][cluster] && \ |
| !tc2_pm_use_count[1][cluster] && \ |
| !tc2_pm_use_count[2][cluster]) |
| |
| static int tc2_pm_power_up(unsigned int cpu, unsigned int cluster) |
| { |
| pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster); |
| if (cluster >= TC2_CLUSTERS || cpu >= tc2_nr_cpus[cluster]) |
| return -EINVAL; |
| |
| /* |
| * Since this is called with IRQs enabled, and no arch_spin_lock_irq |
| * variant exists, we need to disable IRQs manually here. |
| */ |
| local_irq_disable(); |
| arch_spin_lock(&tc2_pm_lock); |
| |
| if (tc2_cluster_unused(cluster)) |
| ve_spc_powerdown(cluster, false); |
| |
| tc2_pm_use_count[cpu][cluster]++; |
| if (tc2_pm_use_count[cpu][cluster] == 1) { |
| ve_spc_set_resume_addr(cluster, cpu, |
| virt_to_phys(mcpm_entry_point)); |
| ve_spc_cpu_wakeup_irq(cluster, cpu, true); |
| } else if (tc2_pm_use_count[cpu][cluster] != 2) { |
| /* |
| * The only possible values are: |
| * 0 = CPU down |
| * 1 = CPU (still) up |
| * 2 = CPU requested to be up before it had a chance |
| * to actually make itself down. |
| * Any other value is a bug. |
| */ |
| BUG(); |
| } |
| |
| arch_spin_unlock(&tc2_pm_lock); |
| local_irq_enable(); |
| |
| return 0; |
| } |
| |
| static void tc2_pm_down(u64 residency) |
| { |
| unsigned int mpidr, cpu, cluster; |
| bool last_man = false, skip_wfi = false; |
| |
| 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); |
| |
| __mcpm_cpu_going_down(cpu, cluster); |
| |
| arch_spin_lock(&tc2_pm_lock); |
| BUG_ON(__mcpm_cluster_state(cluster) != CLUSTER_UP); |
| tc2_pm_use_count[cpu][cluster]--; |
| if (tc2_pm_use_count[cpu][cluster] == 0) { |
| ve_spc_cpu_wakeup_irq(cluster, cpu, true); |
| if (tc2_cluster_unused(cluster)) { |
| ve_spc_powerdown(cluster, true); |
| ve_spc_global_wakeup_irq(true); |
| last_man = true; |
| } |
| } else if (tc2_pm_use_count[cpu][cluster] == 1) { |
| /* |
| * A power_up request went ahead of us. |
| * Even if we do not want to shut this CPU down, |
| * the caller expects a certain state as if the WFI |
| * was aborted. So let's continue with cache cleaning. |
| */ |
| skip_wfi = true; |
| } else |
| BUG(); |
| |
| /* |
| * If the CPU is committed to power down, make sure |
| * the power controller will be in charge of waking it |
| * up upon IRQ, ie IRQ lines are cut from GIC CPU IF |
| * to the CPU by disabling the GIC CPU IF to prevent wfi |
| * from completing execution behind power controller back |
| */ |
| if (!skip_wfi) |
| gic_cpu_if_down(); |
| |
| if (last_man && __mcpm_outbound_enter_critical(cpu, cluster)) { |
| arch_spin_unlock(&tc2_pm_lock); |
| |
| if (read_cpuid_part_number() == ARM_CPU_PART_CORTEX_A15) { |
| /* |
| * On the Cortex-A15 we need to disable |
| * L2 prefetching before flushing the cache. |
| */ |
| asm volatile( |
| "mcr p15, 1, %0, c15, c0, 3 \n\t" |
| "isb \n\t" |
| "dsb " |
| : : "r" (0x400) ); |
| } |
| |
| v7_exit_coherency_flush(all); |
| |
| cci_disable_port_by_cpu(mpidr); |
| |
| __mcpm_outbound_leave_critical(cluster, CLUSTER_DOWN); |
| } else { |
| /* |
| * If last man then undo any setup done previously. |
| */ |
| if (last_man) { |
| ve_spc_powerdown(cluster, false); |
| ve_spc_global_wakeup_irq(false); |
| } |
| |
| arch_spin_unlock(&tc2_pm_lock); |
| |
| v7_exit_coherency_flush(louis); |
| } |
| |
| __mcpm_cpu_down(cpu, cluster); |
| |
| /* Now we are prepared for power-down, do it: */ |
| if (!skip_wfi) |
| wfi(); |
| |
| /* Not dead at this point? Let our caller cope. */ |
| } |
| |
| static void tc2_pm_power_down(void) |
| { |
| tc2_pm_down(0); |
| } |
| |
| static int tc2_core_in_reset(unsigned int cpu, unsigned int cluster) |
| { |
| u32 mask = cluster ? |
| RESET_A7_NCORERESET(cpu) |
| : RESET_A15_NCORERESET(cpu); |
| |
| return !(readl_relaxed(scc + RESET_CTRL) & mask); |
| } |
| |
| #define POLL_MSEC 10 |
| #define TIMEOUT_MSEC 1000 |
| |
| static int tc2_pm_wait_for_powerdown(unsigned int cpu, unsigned int cluster) |
| { |
| unsigned tries; |
| |
| pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster); |
| BUG_ON(cluster >= TC2_CLUSTERS || cpu >= TC2_MAX_CPUS_PER_CLUSTER); |
| |
| for (tries = 0; tries < TIMEOUT_MSEC / POLL_MSEC; ++tries) { |
| /* |
| * Only examine the hardware state if the target CPU has |
| * caught up at least as far as tc2_pm_down(): |
| */ |
| if (ACCESS_ONCE(tc2_pm_use_count[cpu][cluster]) == 0) { |
| pr_debug("%s(cpu=%u, cluster=%u): RESET_CTRL = 0x%08X\n", |
| __func__, cpu, cluster, |
| readl_relaxed(scc + RESET_CTRL)); |
| |
| /* |
| * We need the CPU to reach WFI, but the power |
| * controller may put the cluster in reset and |
| * power it off as soon as that happens, before |
| * we have a chance to see STANDBYWFI. |
| * |
| * So we need to check for both conditions: |
| */ |
| if (tc2_core_in_reset(cpu, cluster) || |
| ve_spc_cpu_in_wfi(cpu, cluster)) |
| return 0; /* success: the CPU is halted */ |
| } |
| |
| /* Otherwise, wait and retry: */ |
| msleep(POLL_MSEC); |
| } |
| |
| return -ETIMEDOUT; /* timeout */ |
| } |
| |
| static void tc2_pm_suspend(u64 residency) |
| { |
| unsigned int mpidr, cpu, cluster; |
| |
| mpidr = read_cpuid_mpidr(); |
| cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0); |
| cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1); |
| ve_spc_set_resume_addr(cluster, cpu, virt_to_phys(mcpm_entry_point)); |
| tc2_pm_down(residency); |
| } |
| |
| static void tc2_pm_powered_up(void) |
| { |
| unsigned int mpidr, cpu, cluster; |
| unsigned long flags; |
| |
| 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); |
| |
| local_irq_save(flags); |
| arch_spin_lock(&tc2_pm_lock); |
| |
| if (tc2_cluster_unused(cluster)) { |
| ve_spc_powerdown(cluster, false); |
| ve_spc_global_wakeup_irq(false); |
| } |
| |
| if (!tc2_pm_use_count[cpu][cluster]) |
| tc2_pm_use_count[cpu][cluster] = 1; |
| |
| ve_spc_cpu_wakeup_irq(cluster, cpu, false); |
| ve_spc_set_resume_addr(cluster, cpu, 0); |
| |
| arch_spin_unlock(&tc2_pm_lock); |
| local_irq_restore(flags); |
| } |
| |
| static const struct mcpm_platform_ops tc2_pm_power_ops = { |
| .power_up = tc2_pm_power_up, |
| .power_down = tc2_pm_power_down, |
| .wait_for_powerdown = tc2_pm_wait_for_powerdown, |
| .suspend = tc2_pm_suspend, |
| .powered_up = tc2_pm_powered_up, |
| }; |
| |
| static bool __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); |
| if (cluster >= TC2_CLUSTERS || cpu >= tc2_nr_cpus[cluster]) { |
| pr_err("%s: boot CPU is out of bound!\n", __func__); |
| return false; |
| } |
| tc2_pm_use_count[cpu][cluster] = 1; |
| return true; |
| } |
| |
| /* |
| * Enable cluster-level coherency, in preparation for turning on the MMU. |
| */ |
| static void __naked tc2_pm_power_up_setup(unsigned int affinity_level) |
| { |
| asm volatile (" \n" |
| " cmp r0, #1 \n" |
| " bxne lr \n" |
| " b cci_enable_port_for_self "); |
| } |
| |
| static int __init tc2_pm_init(void) |
| { |
| int ret, irq; |
| u32 a15_cluster_id, a7_cluster_id, sys_info; |
| struct device_node *np; |
| |
| /* |
| * The power management-related features are hidden behind |
| * SCC registers. We need to extract runtime information like |
| * cluster ids and number of CPUs really available in clusters. |
| */ |
| np = of_find_compatible_node(NULL, NULL, |
| "arm,vexpress-scc,v2p-ca15_a7"); |
| scc = of_iomap(np, 0); |
| if (!scc) |
| return -ENODEV; |
| |
| a15_cluster_id = readl_relaxed(scc + A15_CONF) & 0xf; |
| a7_cluster_id = readl_relaxed(scc + A7_CONF) & 0xf; |
| if (a15_cluster_id >= TC2_CLUSTERS || a7_cluster_id >= TC2_CLUSTERS) |
| return -EINVAL; |
| |
| sys_info = readl_relaxed(scc + SYS_INFO); |
| tc2_nr_cpus[a15_cluster_id] = (sys_info >> 16) & 0xf; |
| tc2_nr_cpus[a7_cluster_id] = (sys_info >> 20) & 0xf; |
| |
| irq = irq_of_parse_and_map(np, 0); |
| |
| /* |
| * A subset of the SCC registers is also used to communicate |
| * with the SPC (power controller). We need to be able to |
| * drive it very early in the boot process to power up |
| * processors, so we initialize the SPC driver here. |
| */ |
| ret = ve_spc_init(scc + SPC_BASE, a15_cluster_id, irq); |
| if (ret) |
| return ret; |
| |
| if (!cci_probed()) |
| return -ENODEV; |
| |
| if (!tc2_pm_usage_count_init()) |
| return -EINVAL; |
| |
| ret = mcpm_platform_register(&tc2_pm_power_ops); |
| if (!ret) { |
| mcpm_sync_init(tc2_pm_power_up_setup); |
| pr_info("TC2 power management initialized\n"); |
| } |
| return ret; |
| } |
| |
| early_initcall(tc2_pm_init); |