diff options
Diffstat (limited to 'arch/arm/mach-versatile/tc2_pm.c')
| -rw-r--r-- | arch/arm/mach-versatile/tc2_pm.c | 261 |
1 files changed, 261 insertions, 0 deletions
diff --git a/arch/arm/mach-versatile/tc2_pm.c b/arch/arm/mach-versatile/tc2_pm.c new file mode 100644 index 000000000..0fe78da0c --- /dev/null +++ b/arch/arm/mach-versatile/tc2_pm.c @@ -0,0 +1,261 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * 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 + */ + +#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/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; + +#define TC2_CLUSTERS 2 +#define TC2_MAX_CPUS_PER_CLUSTER 3 + +static unsigned int tc2_nr_cpus[TC2_CLUSTERS]; + +static int tc2_pm_cpu_powerup(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; + ve_spc_set_resume_addr(cluster, cpu, + __pa_symbol(mcpm_entry_point)); + ve_spc_cpu_wakeup_irq(cluster, cpu, true); + return 0; +} + +static int tc2_pm_cluster_powerup(unsigned int cluster) +{ + pr_debug("%s: cluster %u\n", __func__, cluster); + if (cluster >= TC2_CLUSTERS) + return -EINVAL; + ve_spc_powerdown(cluster, false); + return 0; +} + +static void tc2_pm_cpu_powerdown_prepare(unsigned int cpu, unsigned int cluster) +{ + pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster); + BUG_ON(cluster >= TC2_CLUSTERS || cpu >= TC2_MAX_CPUS_PER_CLUSTER); + ve_spc_cpu_wakeup_irq(cluster, cpu, true); + /* + * 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 + */ + gic_cpu_if_down(0); +} + +static void tc2_pm_cluster_powerdown_prepare(unsigned int cluster) +{ + pr_debug("%s: cluster %u\n", __func__, cluster); + BUG_ON(cluster >= TC2_CLUSTERS); + ve_spc_powerdown(cluster, true); + ve_spc_global_wakeup_irq(true); +} + +static void tc2_pm_cpu_cache_disable(void) +{ + v7_exit_coherency_flush(louis); +} + +static void tc2_pm_cluster_cache_disable(void) +{ + if (read_cpuid_part() == 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(read_cpuid_mpidr()); +} + +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) { + 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_cpu_suspend_prepare(unsigned int cpu, unsigned int cluster) +{ + ve_spc_set_resume_addr(cluster, cpu, __pa_symbol(mcpm_entry_point)); +} + +static void tc2_pm_cpu_is_up(unsigned int cpu, unsigned int cluster) +{ + pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster); + BUG_ON(cluster >= TC2_CLUSTERS || cpu >= TC2_MAX_CPUS_PER_CLUSTER); + ve_spc_cpu_wakeup_irq(cluster, cpu, false); + ve_spc_set_resume_addr(cluster, cpu, 0); +} + +static void tc2_pm_cluster_is_up(unsigned int cluster) +{ + pr_debug("%s: cluster %u\n", __func__, cluster); + BUG_ON(cluster >= TC2_CLUSTERS); + ve_spc_powerdown(cluster, false); + ve_spc_global_wakeup_irq(false); +} + +static const struct mcpm_platform_ops tc2_pm_power_ops = { + .cpu_powerup = tc2_pm_cpu_powerup, + .cluster_powerup = tc2_pm_cluster_powerup, + .cpu_suspend_prepare = tc2_pm_cpu_suspend_prepare, + .cpu_powerdown_prepare = tc2_pm_cpu_powerdown_prepare, + .cluster_powerdown_prepare = tc2_pm_cluster_powerdown_prepare, + .cpu_cache_disable = tc2_pm_cpu_cache_disable, + .cluster_cache_disable = tc2_pm_cluster_cache_disable, + .wait_for_powerdown = tc2_pm_wait_for_powerdown, + .cpu_is_up = tc2_pm_cpu_is_up, + .cluster_is_up = tc2_pm_cluster_is_up, +}; + +/* + * 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) +{ + unsigned int mpidr, cpu, cluster; + 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; + + 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 -EINVAL; + } + + ret = mcpm_platform_register(&tc2_pm_power_ops); + if (!ret) { + mcpm_sync_init(tc2_pm_power_up_setup); + /* test if we can (re)enable the CCI on our own */ + BUG_ON(mcpm_loopback(tc2_pm_cluster_cache_disable) != 0); + pr_info("TC2 power management initialized\n"); + } + return ret; +} + +early_initcall(tc2_pm_init); |