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-rw-r--r--arch/arm/mach-versatile/tc2_pm.c261
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
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+++ b/arch/arm/mach-versatile/tc2_pm.c
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+// 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);