359 lines
9.1 KiB
C
359 lines
9.1 KiB
C
/*
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* Copyright (c) 2014 Samsung Electronics Co., Ltd.
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* http://www.samsung.com
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*
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* arch/arm/mach-exynos/mcpm-exynos.c
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*
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* Based on arch/arm/mach-vexpress/dcscb.c
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/arm-cci.h>
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#include <linux/delay.h>
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#include <linux/io.h>
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#include <linux/of_address.h>
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#include <asm/cputype.h>
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#include <asm/cp15.h>
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#include <asm/mcpm.h>
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#include "regs-pmu.h"
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#include "common.h"
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#define EXYNOS5420_CPUS_PER_CLUSTER 4
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#define EXYNOS5420_NR_CLUSTERS 2
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/*
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* The common v7_exit_coherency_flush API could not be used because of the
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* Erratum 799270 workaround. This macro is the same as the common one (in
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* arch/arm/include/asm/cacheflush.h) except for the erratum handling.
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*/
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#define exynos_v7_exit_coherency_flush(level) \
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asm volatile( \
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"stmfd sp!, {fp, ip}\n\t"\
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"mrc p15, 0, r0, c1, c0, 0 @ get SCTLR\n\t" \
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"bic r0, r0, #"__stringify(CR_C)"\n\t" \
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"mcr p15, 0, r0, c1, c0, 0 @ set SCTLR\n\t" \
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"isb\n\t"\
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"bl v7_flush_dcache_"__stringify(level)"\n\t" \
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"clrex\n\t"\
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"mrc p15, 0, r0, c1, c0, 1 @ get ACTLR\n\t" \
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"bic r0, r0, #(1 << 6) @ disable local coherency\n\t" \
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/* Dummy Load of a device register to avoid Erratum 799270 */ \
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"ldr r4, [%0]\n\t" \
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"and r4, r4, #0\n\t" \
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"orr r0, r0, r4\n\t" \
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"mcr p15, 0, r0, c1, c0, 1 @ set ACTLR\n\t" \
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"isb\n\t" \
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"dsb\n\t" \
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"ldmfd sp!, {fp, ip}" \
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: \
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: "Ir" (S5P_INFORM0) \
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: "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7", \
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"r9", "r10", "lr", "memory")
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/*
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* We can't use regular spinlocks. In the switcher case, it is possible
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* for an outbound CPU to call power_down() after its inbound counterpart
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* is already live using the same logical CPU number which trips lockdep
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* debugging.
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*/
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static arch_spinlock_t exynos_mcpm_lock = __ARCH_SPIN_LOCK_UNLOCKED;
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static int
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cpu_use_count[EXYNOS5420_CPUS_PER_CLUSTER][EXYNOS5420_NR_CLUSTERS];
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#define exynos_cluster_usecnt(cluster) \
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(cpu_use_count[0][cluster] + \
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cpu_use_count[1][cluster] + \
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cpu_use_count[2][cluster] + \
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cpu_use_count[3][cluster])
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#define exynos_cluster_unused(cluster) !exynos_cluster_usecnt(cluster)
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static int exynos_cluster_power_control(unsigned int cluster, int enable)
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{
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unsigned int tries = 100;
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unsigned int val;
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if (enable) {
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exynos_cluster_power_up(cluster);
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val = S5P_CORE_LOCAL_PWR_EN;
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} else {
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exynos_cluster_power_down(cluster);
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val = 0;
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}
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/* Wait until cluster power control is applied */
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while (tries--) {
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if (exynos_cluster_power_state(cluster) == val)
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return 0;
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cpu_relax();
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}
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pr_debug("timed out waiting for cluster %u to power %s\n", cluster,
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enable ? "on" : "off");
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return -ETIMEDOUT;
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}
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static int exynos_power_up(unsigned int cpu, unsigned int cluster)
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{
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unsigned int cpunr = cpu + (cluster * EXYNOS5420_CPUS_PER_CLUSTER);
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int err = 0;
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pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
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if (cpu >= EXYNOS5420_CPUS_PER_CLUSTER ||
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cluster >= EXYNOS5420_NR_CLUSTERS)
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return -EINVAL;
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/*
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* Since this is called with IRQs enabled, and no arch_spin_lock_irq
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* variant exists, we need to disable IRQs manually here.
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*/
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local_irq_disable();
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arch_spin_lock(&exynos_mcpm_lock);
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cpu_use_count[cpu][cluster]++;
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if (cpu_use_count[cpu][cluster] == 1) {
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bool was_cluster_down =
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(exynos_cluster_usecnt(cluster) == 1);
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/*
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* Turn on the cluster (L2/COMMON) and then power on the
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* cores.
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*/
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if (was_cluster_down)
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err = exynos_cluster_power_control(cluster, 1);
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if (!err)
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exynos_cpu_power_up(cpunr);
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else
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exynos_cluster_power_control(cluster, 0);
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} else if (cpu_use_count[cpu][cluster] != 2) {
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/*
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* The only possible values are:
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* 0 = CPU down
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* 1 = CPU (still) up
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* 2 = CPU requested to be up before it had a chance
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* to actually make itself down.
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* Any other value is a bug.
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*/
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BUG();
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}
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arch_spin_unlock(&exynos_mcpm_lock);
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local_irq_enable();
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return err;
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}
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/*
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* NOTE: This function requires the stack data to be visible through power down
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* and can only be executed on processors like A15 and A7 that hit the cache
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* with the C bit clear in the SCTLR register.
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*/
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static void exynos_power_down(void)
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{
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unsigned int mpidr, cpu, cluster;
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bool last_man = false, skip_wfi = false;
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unsigned int cpunr;
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mpidr = read_cpuid_mpidr();
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cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
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cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
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cpunr = cpu + (cluster * EXYNOS5420_CPUS_PER_CLUSTER);
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pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
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BUG_ON(cpu >= EXYNOS5420_CPUS_PER_CLUSTER ||
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cluster >= EXYNOS5420_NR_CLUSTERS);
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__mcpm_cpu_going_down(cpu, cluster);
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arch_spin_lock(&exynos_mcpm_lock);
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BUG_ON(__mcpm_cluster_state(cluster) != CLUSTER_UP);
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cpu_use_count[cpu][cluster]--;
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if (cpu_use_count[cpu][cluster] == 0) {
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exynos_cpu_power_down(cpunr);
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if (exynos_cluster_unused(cluster))
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/* TODO: Turn off the cluster here to save power. */
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last_man = true;
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} else if (cpu_use_count[cpu][cluster] == 1) {
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/*
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* A power_up request went ahead of us.
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* Even if we do not want to shut this CPU down,
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* the caller expects a certain state as if the WFI
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* was aborted. So let's continue with cache cleaning.
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*/
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skip_wfi = true;
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} else {
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BUG();
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}
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if (last_man && __mcpm_outbound_enter_critical(cpu, cluster)) {
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arch_spin_unlock(&exynos_mcpm_lock);
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if (read_cpuid_part_number() == ARM_CPU_PART_CORTEX_A15) {
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/*
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* On the Cortex-A15 we need to disable
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* L2 prefetching before flushing the cache.
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*/
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asm volatile(
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"mcr p15, 1, %0, c15, c0, 3\n\t"
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"isb\n\t"
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"dsb"
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: : "r" (0x400));
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}
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/* Flush all cache levels for this cluster. */
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exynos_v7_exit_coherency_flush(all);
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/*
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* Disable cluster-level coherency by masking
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* incoming snoops and DVM messages:
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*/
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cci_disable_port_by_cpu(mpidr);
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__mcpm_outbound_leave_critical(cluster, CLUSTER_DOWN);
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} else {
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arch_spin_unlock(&exynos_mcpm_lock);
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/* Disable and flush the local CPU cache. */
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exynos_v7_exit_coherency_flush(louis);
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}
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__mcpm_cpu_down(cpu, cluster);
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/* Now we are prepared for power-down, do it: */
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if (!skip_wfi)
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wfi();
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/* Not dead at this point? Let our caller cope. */
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}
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static int exynos_wait_for_powerdown(unsigned int cpu, unsigned int cluster)
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{
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unsigned int tries = 100;
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unsigned int cpunr = cpu + (cluster * EXYNOS5420_CPUS_PER_CLUSTER);
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pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
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BUG_ON(cpu >= EXYNOS5420_CPUS_PER_CLUSTER ||
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cluster >= EXYNOS5420_NR_CLUSTERS);
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/* Wait for the core state to be OFF */
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while (tries--) {
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if (ACCESS_ONCE(cpu_use_count[cpu][cluster]) == 0) {
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if ((exynos_cpu_power_state(cpunr) == 0))
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return 0; /* success: the CPU is halted */
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}
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/* Otherwise, wait and retry: */
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msleep(1);
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}
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return -ETIMEDOUT; /* timeout */
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}
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static const struct mcpm_platform_ops exynos_power_ops = {
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.power_up = exynos_power_up,
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.power_down = exynos_power_down,
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.wait_for_powerdown = exynos_wait_for_powerdown,
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};
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static void __init exynos_mcpm_usage_count_init(void)
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{
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unsigned int mpidr, cpu, cluster;
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mpidr = read_cpuid_mpidr();
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cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
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cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
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pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
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BUG_ON(cpu >= EXYNOS5420_CPUS_PER_CLUSTER ||
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cluster >= EXYNOS5420_NR_CLUSTERS);
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cpu_use_count[cpu][cluster] = 1;
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}
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/*
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* Enable cluster-level coherency, in preparation for turning on the MMU.
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*/
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static void __naked exynos_pm_power_up_setup(unsigned int affinity_level)
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{
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asm volatile ("\n"
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"cmp r0, #1\n"
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"bxne lr\n"
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"b cci_enable_port_for_self");
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}
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static const struct of_device_id exynos_dt_mcpm_match[] = {
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{ .compatible = "samsung,exynos5420" },
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{ .compatible = "samsung,exynos5800" },
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{},
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};
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static int __init exynos_mcpm_init(void)
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{
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struct device_node *node;
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void __iomem *ns_sram_base_addr;
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int ret;
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node = of_find_matching_node(NULL, exynos_dt_mcpm_match);
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if (!node)
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return -ENODEV;
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of_node_put(node);
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if (!cci_probed())
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return -ENODEV;
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node = of_find_compatible_node(NULL, NULL,
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"samsung,exynos4210-sysram-ns");
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if (!node)
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return -ENODEV;
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ns_sram_base_addr = of_iomap(node, 0);
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of_node_put(node);
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if (!ns_sram_base_addr) {
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pr_err("failed to map non-secure iRAM base address\n");
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return -ENOMEM;
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}
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/*
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* To increase the stability of KFC reset we need to program
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* the PMU SPARE3 register
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*/
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__raw_writel(EXYNOS5420_SWRESET_KFC_SEL, S5P_PMU_SPARE3);
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exynos_mcpm_usage_count_init();
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ret = mcpm_platform_register(&exynos_power_ops);
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if (!ret)
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ret = mcpm_sync_init(exynos_pm_power_up_setup);
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if (ret) {
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iounmap(ns_sram_base_addr);
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return ret;
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}
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mcpm_smp_set_ops();
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pr_info("Exynos MCPM support installed\n");
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/*
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* U-Boot SPL is hardcoded to jump to the start of ns_sram_base_addr
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* as part of secondary_cpu_start(). Let's redirect it to the
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* mcpm_entry_point().
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*/
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__raw_writel(0xe59f0000, ns_sram_base_addr); /* ldr r0, [pc, #0] */
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__raw_writel(0xe12fff10, ns_sram_base_addr + 4); /* bx r0 */
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__raw_writel(virt_to_phys(mcpm_entry_point), ns_sram_base_addr + 8);
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iounmap(ns_sram_base_addr);
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return ret;
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}
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early_initcall(exynos_mcpm_init);
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