--- /dev/null
+/*
+ * Copyright (c) 2014 Samsung Electronics Co., Ltd.
+ * http://www.samsung.com
+ *
+ * arch/arm/mach-exynos/mcpm-exynos.c
+ *
+ * Based on arch/arm/mach-vexpress/dcscb.c
+ *
+ * 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/arm-cci.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/of_address.h>
+
+#include <asm/cputype.h>
+#include <asm/cp15.h>
+#include <asm/mcpm.h>
+
+#include "regs-pmu.h"
+#include "common.h"
+
+#define EXYNOS5420_CPUS_PER_CLUSTER 4
+#define EXYNOS5420_NR_CLUSTERS 2
+#define MCPM_BOOT_ADDR_OFFSET 0x1c
+
+/*
+ * The common v7_exit_coherency_flush API could not be used because of the
+ * Erratum 799270 workaround. This macro is the same as the common one (in
+ * arch/arm/include/asm/cacheflush.h) except for the erratum handling.
+ */
+#define exynos_v7_exit_coherency_flush(level) \
+ asm volatile( \
+ "stmfd sp!, {fp, ip}\n\t"\
+ "mrc p15, 0, r0, c1, c0, 0 @ get SCTLR\n\t" \
+ "bic r0, r0, #"__stringify(CR_C)"\n\t" \
+ "mcr p15, 0, r0, c1, c0, 0 @ set SCTLR\n\t" \
+ "isb\n\t"\
+ "bl v7_flush_dcache_"__stringify(level)"\n\t" \
+ "clrex\n\t"\
+ "mrc p15, 0, r0, c1, c0, 1 @ get ACTLR\n\t" \
+ "bic r0, r0, #(1 << 6) @ disable local coherency\n\t" \
+ /* Dummy Load of a device register to avoid Erratum 799270 */ \
+ "ldr r4, [%0]\n\t" \
+ "and r4, r4, #0\n\t" \
+ "orr r0, r0, r4\n\t" \
+ "mcr p15, 0, r0, c1, c0, 1 @ set ACTLR\n\t" \
+ "isb\n\t" \
+ "dsb\n\t" \
+ "ldmfd sp!, {fp, ip}" \
+ : \
+ : "Ir" (S5P_INFORM0) \
+ : "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7", \
+ "r9", "r10", "lr", "memory")
+
+/*
+ * 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 exynos_mcpm_lock = __ARCH_SPIN_LOCK_UNLOCKED;
+static int
+cpu_use_count[EXYNOS5420_CPUS_PER_CLUSTER][EXYNOS5420_NR_CLUSTERS];
+
+#define exynos_cluster_usecnt(cluster) \
+ (cpu_use_count[0][cluster] + \
+ cpu_use_count[1][cluster] + \
+ cpu_use_count[2][cluster] + \
+ cpu_use_count[3][cluster])
+
+#define exynos_cluster_unused(cluster) !exynos_cluster_usecnt(cluster)
+
+static int exynos_cluster_power_control(unsigned int cluster, int enable)
+{
+ unsigned int tries = 100;
+ unsigned int val;
+
+ if (enable) {
+ exynos_cluster_power_up(cluster);
+ val = S5P_CORE_LOCAL_PWR_EN;
+ } else {
+ exynos_cluster_power_down(cluster);
+ val = 0;
+ }
+
+ /* Wait until cluster power control is applied */
+ while (tries--) {
+ if (exynos_cluster_power_state(cluster) == val)
+ return 0;
+
+ cpu_relax();
+ }
+ pr_debug("timed out waiting for cluster %u to power %s\n", cluster,
+ enable ? "on" : "off");
+
+ return -ETIMEDOUT;
+}
+
+static int exynos_power_up(unsigned int cpu, unsigned int cluster)
+{
+ unsigned int cpunr = cpu + (cluster * EXYNOS5420_CPUS_PER_CLUSTER);
+ int err = 0;
+
+ pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
+ if (cpu >= EXYNOS5420_CPUS_PER_CLUSTER ||
+ cluster >= EXYNOS5420_NR_CLUSTERS)
+ 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(&exynos_mcpm_lock);
+
+ cpu_use_count[cpu][cluster]++;
+ if (cpu_use_count[cpu][cluster] == 1) {
+ bool was_cluster_down =
+ (exynos_cluster_usecnt(cluster) == 1);
+
+ /*
+ * Turn on the cluster (L2/COMMON) and then power on the
+ * cores.
+ */
+ if (was_cluster_down)
+ err = exynos_cluster_power_control(cluster, 1);
+
+ if (!err)
+ exynos_cpu_power_up(cpunr);
+ else
+ exynos_cluster_power_control(cluster, 0);
+ } else if (cpu_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(&exynos_mcpm_lock);
+ local_irq_enable();
+
+ return err;
+}
+
+/*
+ * NOTE: This function requires the stack data to be visible through power down
+ * and can only be executed on processors like A15 and A7 that hit the cache
+ * with the C bit clear in the SCTLR register.
+ */
+static void exynos_power_down(void)
+{
+ unsigned int mpidr, cpu, cluster;
+ bool last_man = false, skip_wfi = false;
+ unsigned int cpunr;
+
+ mpidr = read_cpuid_mpidr();
+ cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
+ cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
+ cpunr = cpu + (cluster * EXYNOS5420_CPUS_PER_CLUSTER);
+
+ pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
+ BUG_ON(cpu >= EXYNOS5420_CPUS_PER_CLUSTER ||
+ cluster >= EXYNOS5420_NR_CLUSTERS);
+
+ __mcpm_cpu_going_down(cpu, cluster);
+
+ arch_spin_lock(&exynos_mcpm_lock);
+ BUG_ON(__mcpm_cluster_state(cluster) != CLUSTER_UP);
+ cpu_use_count[cpu][cluster]--;
+ if (cpu_use_count[cpu][cluster] == 0) {
+ exynos_cpu_power_down(cpunr);
+
+ if (exynos_cluster_unused(cluster))
+ /* TODO: Turn off the cluster here to save power. */
+ last_man = true;
+ } else if (cpu_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 (last_man && __mcpm_outbound_enter_critical(cpu, cluster)) {
+ arch_spin_unlock(&exynos_mcpm_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));
+ }
+
+ /* Flush all cache levels for this cluster. */
+ exynos_v7_exit_coherency_flush(all);
+
+ /*
+ * Disable cluster-level coherency by masking
+ * incoming snoops and DVM messages:
+ */
+ cci_disable_port_by_cpu(mpidr);
+
+ __mcpm_outbound_leave_critical(cluster, CLUSTER_DOWN);
+ } else {
+ arch_spin_unlock(&exynos_mcpm_lock);
+
+ /* Disable and flush the local CPU cache. */
+ exynos_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 int exynos_power_down_finish(unsigned int cpu, unsigned int cluster)
+{
+ unsigned int tries = 100;
+ unsigned int cpunr = cpu + (cluster * EXYNOS5420_CPUS_PER_CLUSTER);
+
+ pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
+ BUG_ON(cpu >= EXYNOS5420_CPUS_PER_CLUSTER ||
+ cluster >= EXYNOS5420_NR_CLUSTERS);
+
+ /* Wait for the core state to be OFF */
+ while (tries--) {
+ if (ACCESS_ONCE(cpu_use_count[cpu][cluster]) == 0) {
+ if ((exynos_cpu_power_state(cpunr) == 0))
+ return 0; /* success: the CPU is halted */
+ }
+
+ /* Otherwise, wait and retry: */
+ msleep(1);
+ }
+
+ return -ETIMEDOUT; /* timeout */
+}
+
+static const struct mcpm_platform_ops exynos_power_ops = {
+ .power_up = exynos_power_up,
+ .power_down = exynos_power_down,
+ .power_down_finish = exynos_power_down_finish,
+};
+
+static void __init exynos_mcpm_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(cpu >= EXYNOS5420_CPUS_PER_CLUSTER ||
+ cluster >= EXYNOS5420_NR_CLUSTERS);
+
+ cpu_use_count[cpu][cluster] = 1;
+}
+
+/*
+ * Enable cluster-level coherency, in preparation for turning on the MMU.
+ */
+static void __naked exynos_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 exynos_mcpm_init(void)
+{
+ struct device_node *node;
+ void __iomem *ns_sram_base_addr;
+ int ret;
+
+ node = of_find_compatible_node(NULL, NULL, "samsung,exynos5420");
+ if (!node)
+ return -ENODEV;
+ of_node_put(node);
+
+ if (!cci_probed())
+ return -ENODEV;
+
+ node = of_find_compatible_node(NULL, NULL,
+ "samsung,exynos4210-sysram-ns");
+ if (!node)
+ return -ENODEV;
+
+ ns_sram_base_addr = of_iomap(node, 0);
+ of_node_put(node);
+ if (!ns_sram_base_addr) {
+ pr_err("failed to map non-secure iRAM base address\n");
+ return -ENOMEM;
+ }
+
+ /*
+ * To increase the stability of KFC reset we need to program
+ * the PMU SPARE3 register
+ */
+ __raw_writel(EXYNOS5420_SWRESET_KFC_SEL, S5P_PMU_SPARE3);
+
+ exynos_mcpm_usage_count_init();
+
+ ret = mcpm_platform_register(&exynos_power_ops);
+ if (!ret)
+ ret = mcpm_sync_init(exynos_pm_power_up_setup);
+ if (ret) {
+ iounmap(ns_sram_base_addr);
+ return ret;
+ }
+
+ mcpm_smp_set_ops();
+
+ pr_info("Exynos MCPM support installed\n");
+
+ /*
+ * Future entries into the kernel can now go
+ * through the cluster entry vectors.
+ */
+ __raw_writel(virt_to_phys(mcpm_entry_point),
+ ns_sram_base_addr + MCPM_BOOT_ADDR_OFFSET);
+
+ iounmap(ns_sram_base_addr);
+
+ return ret;
+}
+
+early_initcall(exynos_mcpm_init);
projects / karo-tx-linux.git / commitdiff