[PATCH v3 5/6] arm: exynos: Add MCPM call-back functions
Abhilash Kesavan
a.kesavan at samsung.com
Sat Apr 26 09:05:47 PDT 2014
Add machine-dependent MCPM call-backs for Exynos5420. These are used
to power up/down the secondary CPUs during boot, shutdown, s2r and
switching.
Signed-off-by: Thomas Abraham <thomas.ab at samsung.com>
Signed-off-by: Inderpal Singh <inderpal.s at samsung.com>
Signed-off-by: Andrew Bresticker <abrestic at chromium.org>
Signed-off-by: Abhilash Kesavan <a.kesavan at samsung.com>
---
arch/arm/mach-exynos/Kconfig | 8 +
arch/arm/mach-exynos/Makefile | 2 +
arch/arm/mach-exynos/mcpm-exynos.c | 321 +++++++++++++++++++++++++++++++++++++
arch/arm/mach-exynos/regs-pmu.h | 3 +
4 files changed, 334 insertions(+)
create mode 100644 arch/arm/mach-exynos/mcpm-exynos.c
diff --git a/arch/arm/mach-exynos/Kconfig b/arch/arm/mach-exynos/Kconfig
index fc8bf18..1602abc 100644
--- a/arch/arm/mach-exynos/Kconfig
+++ b/arch/arm/mach-exynos/Kconfig
@@ -110,4 +110,12 @@ config SOC_EXYNOS5440
endmenu
+config EXYNOS5420_MCPM
+ bool "Exynos5420 Multi-Cluster PM support"
+ depends on MCPM && SOC_EXYNOS5420
+ select ARM_CCI
+ help
+ This is needed to provide CPU and cluster power management
+ on Exynos5420 implementing big.LITTLE.
+
endif
diff --git a/arch/arm/mach-exynos/Makefile b/arch/arm/mach-exynos/Makefile
index a656dbe..01bc9b9 100644
--- a/arch/arm/mach-exynos/Makefile
+++ b/arch/arm/mach-exynos/Makefile
@@ -29,3 +29,5 @@ obj-$(CONFIG_ARCH_EXYNOS) += firmware.o
plus_sec := $(call as-instr,.arch_extension sec,+sec)
AFLAGS_exynos-smc.o :=-Wa,-march=armv7-a$(plus_sec)
+
+obj-$(CONFIG_EXYNOS5420_MCPM) += mcpm-exynos.o
diff --git a/arch/arm/mach-exynos/mcpm-exynos.c b/arch/arm/mach-exynos/mcpm-exynos.c
new file mode 100644
index 0000000..f9977bf
--- /dev/null
+++ b/arch/arm/mach-exynos/mcpm-exynos.c
@@ -0,0 +1,321 @@
+/*
+ * 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/kernel.h>
+#include <linux/io.h>
+#include <linux/spinlock.h>
+#include <linux/uaccess.h>
+#include <linux/miscdevice.h>
+#include <linux/fs.h>
+#include <linux/delay.h>
+#include <linux/arm-cci.h>
+
+#include <asm/mcpm.h>
+#include <asm/cputype.h>
+#include <asm/cp15.h>
+
+#include <plat/cpu.h>
+
+#include "regs-pmu.h"
+#include "common.h"
+
+#define EXYNOS5420_CPUS_PER_CLUSTER 4
+#define EXYNOS5420_NR_CLUSTERS 2
+
+/* Secondary CPU entry point */
+#define REG_ENTRY_ADDR (S5P_VA_SYSRAM_NS + 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];
+
+static int exynos_cluster_power_control(unsigned int cluster, int enable)
+{
+ unsigned int tries = 100;
+ unsigned int val = 0;
+
+ if (enable) {
+ exynos_cluster_powerup(cluster);
+ val = S5P_CORE_LOCAL_PWR_EN;
+ } else {
+ exynos_cluster_powerdown(cluster);
+ }
+
+ /* Wait until cluster power control is applied */
+ while (tries--) {
+ if (exynos_cluster_power_state(cluster) == val)
+ return 0;
+
+ cpu_relax();
+ }
+ pr_warn("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);
+ unsigned int err;
+
+ 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 =
+ __mcpm_cluster_state(cluster) == CLUSTER_DOWN;
+
+ /*
+ * Turn on the cluster (L2/COMMON) and then power on the cores.
+ * TODO: Turn off the clusters when all cores in the cluster
+ * are down to achieve significant power savings.
+ */
+ if (was_cluster_down) {
+ err = exynos_cluster_power_control(cluster, 1);
+ if (err) {
+ exynos_cluster_power_control(cluster, 0);
+ return err;
+ }
+ }
+
+ exynos_cpu_powerup(cpunr);
+
+ /* CPU should be powered up there */
+ /* Also setup Cluster Power Sequence here */
+ } 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 0;
+}
+
+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) {
+ int cnt = 0, i;
+
+ exynos_cpu_powerdown(cpunr);
+ for (i = 0; i < EXYNOS5420_CPUS_PER_CLUSTER; i++)
+ cnt += cpu_use_count[i][cluster];
+ if (cnt == 0)
+ 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);
+
+ /* 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)
+{
+ int ret = 0;
+
+ if (!soc_is_exynos5420())
+ return -ENODEV;
+
+ if (!cci_probed())
+ return -ENODEV;
+
+ /*
+ * 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)
+ 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),
+ REG_ENTRY_ADDR);
+
+ return ret;
+}
+
+early_initcall(exynos_mcpm_init);
diff --git a/arch/arm/mach-exynos/regs-pmu.h b/arch/arm/mach-exynos/regs-pmu.h
index 6685ebf..f44d318 100644
--- a/arch/arm/mach-exynos/regs-pmu.h
+++ b/arch/arm/mach-exynos/regs-pmu.h
@@ -38,6 +38,7 @@
#define S5P_INFORM5 S5P_PMUREG(0x0814)
#define S5P_INFORM6 S5P_PMUREG(0x0818)
#define S5P_INFORM7 S5P_PMUREG(0x081C)
+#define S5P_PMU_SPARE3 S5P_PMUREG(0x090C)
#define S5P_ARM_CORE0_LOWPWR S5P_PMUREG(0x1000)
#define S5P_DIS_IRQ_CORE0 S5P_PMUREG(0x1004)
@@ -325,4 +326,6 @@
#define EXYNOS5_OPTION_USE_RETENTION (1 << 4)
+#define EXYNOS5420_SWRESET_KFC_SEL 0x3
+
#endif /* __ASM_ARCH_REGS_PMU_H */
--
1.8.3.2
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