ARM: EXYNOS: Add MCPM call-back functions

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@samsung.com>
Signed-off-by: Inderpal Singh <inderpal.s@samsung.com>
Signed-off-by: Andrew Bresticker <abrestic@chromium.org>
Signed-off-by: Abhilash Kesavan <a.kesavan@samsung.com>
Reviewed-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

1 files changed, 351 insertions, 0 deletions

diff --git a/arch/arm/mach-exynos/mcpm-exynos.c b/arch/arm/mach-exynos/mcpm-exynos.c
new file mode 100644
index 000000000000..1ac618ce440b
--- /dev/null
+++ b/arch/arm/mach-exynos/mcpm-exynos.c
@@ -0,0 +1,351 @@
+/*
+ * 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);