1 files changed, 124 insertions, 0 deletions
diff --git a/arch/arm/kernel/smp_scu.c b/arch/arm/kernel/smp_scu.c
new file mode 100644
index 000000000..6de47fb3b
--- /dev/null
+++ b/arch/arm/kernel/smp_scu.c
@@ -0,0 +1,124 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  linux/arch/arm/kernel/smp_scu.c
+ *
+ *  Copyright (C) 2002 ARM Ltd.
+ *  All Rights Reserved
+ */
+#include <linux/init.h>
+#include <linux/io.h>
+
+#include <asm/smp_plat.h>
+#include <asm/smp_scu.h>
+#include <asm/cacheflush.h>
+#include <asm/cputype.h>
+
+#define SCU_CTRL		0x00
+#define SCU_ENABLE		(1 << 0)
+#define SCU_STANDBY_ENABLE	(1 << 5)
+#define SCU_CONFIG		0x04
+#define SCU_CPU_STATUS		0x08
+#define SCU_CPU_STATUS_MASK	GENMASK(1, 0)
+#define SCU_INVALIDATE		0x0c
+#define SCU_FPGA_REVISION	0x10
+
+#ifdef CONFIG_SMP
+/*
+ * Get the number of CPU cores from the SCU configuration
+ */
+unsigned int __init scu_get_core_count(void __iomem *scu_base)
+{
+	unsigned int ncores = readl_relaxed(scu_base + SCU_CONFIG);
+	return (ncores & 0x03) + 1;
+}
+
+/*
+ * Enable the SCU
+ */
+void scu_enable(void __iomem *scu_base)
+{
+	u32 scu_ctrl;
+
+#ifdef CONFIG_ARM_ERRATA_764369
+	/* Cortex-A9 only */
+	if ((read_cpuid_id() & 0xff0ffff0) == 0x410fc090) {
+		scu_ctrl = readl_relaxed(scu_base + 0x30);
+		if (!(scu_ctrl & 1))
+			writel_relaxed(scu_ctrl | 0x1, scu_base + 0x30);
+	}
+#endif
+
+	scu_ctrl = readl_relaxed(scu_base + SCU_CTRL);
+	/* already enabled? */
+	if (scu_ctrl & SCU_ENABLE)
+		return;
+
+	scu_ctrl |= SCU_ENABLE;
+
+	/* Cortex-A9 earlier than r2p0 has no standby bit in SCU */
+	if ((read_cpuid_id() & 0xff0ffff0) == 0x410fc090 &&
+	    (read_cpuid_id() & 0x00f0000f) >= 0x00200000)
+		scu_ctrl |= SCU_STANDBY_ENABLE;
+
+	writel_relaxed(scu_ctrl, scu_base + SCU_CTRL);
+
+	/*
+	 * Ensure that the data accessed by CPU0 before the SCU was
+	 * initialised is visible to the other CPUs.
+	 */
+	flush_cache_all();
+}
+#endif
+
+static int scu_set_power_mode_internal(void __iomem *scu_base,
+				       unsigned int logical_cpu,
+				       unsigned int mode)
+{
+	unsigned int val;
+	int cpu = MPIDR_AFFINITY_LEVEL(cpu_logical_map(logical_cpu), 0);
+
+	if (mode > 3 || mode == 1 || cpu > 3)
+		return -EINVAL;
+
+	val = readb_relaxed(scu_base + SCU_CPU_STATUS + cpu);
+	val &= ~SCU_CPU_STATUS_MASK;
+	val |= mode;
+	writeb_relaxed(val, scu_base + SCU_CPU_STATUS + cpu);
+
+	return 0;
+}
+
+/*
+ * Set the executing CPUs power mode as defined.  This will be in
+ * preparation for it executing a WFI instruction.
+ *
+ * This function must be called with preemption disabled, and as it
+ * has the side effect of disabling coherency, caches must have been
+ * flushed.  Interrupts must also have been disabled.
+ */
+int scu_power_mode(void __iomem *scu_base, unsigned int mode)
+{
+	return scu_set_power_mode_internal(scu_base, smp_processor_id(), mode);
+}
+
+/*
+ * Set the given (logical) CPU's power mode to SCU_PM_NORMAL.
+ */
+int scu_cpu_power_enable(void __iomem *scu_base, unsigned int cpu)
+{
+	return scu_set_power_mode_internal(scu_base, cpu, SCU_PM_NORMAL);
+}
+
+int scu_get_cpu_power_mode(void __iomem *scu_base, unsigned int logical_cpu)
+{
+	unsigned int val;
+	int cpu = MPIDR_AFFINITY_LEVEL(cpu_logical_map(logical_cpu), 0);
+
+	if (cpu > 3)
+		return -EINVAL;
+
+	val = readb_relaxed(scu_base + SCU_CPU_STATUS + cpu);
+	val &= SCU_CPU_STATUS_MASK;
+
+	return val;
+}