ARM: Add platform support for LSI AXM55xx SoC

The AXM55xx family consists of devices that may contain up to 16 ARM Cortex-A15
cores (in a 4x4 cluster configuration). The cores within each cluster share an
L2 cache, and the clusters are connected to each other via a CCN-504 cache
coherent interconnect.

This machine requires CONFIG_ARM_LPAE enabled as all peripherals are located
above 4GB in the memory map.

Signed-off-by: Anders Berg <anders.berg@lsi.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

arch/arm/mach-axxia/platsmp.c

@@ -0,0 +1,89 @@
+/*
+ * linux/arch/arm/mach-axxia/platsmp.c
+ *
+ * Copyright (C) 2012 LSI Corporation
+ *
+ * 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/init.h>
+#include <linux/io.h>
+#include <linux/smp.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <asm/cacheflush.h>
+
+/* Syscon register offsets for releasing cores from reset */
+#define SC_CRIT_WRITE_KEY	0x1000
+#define SC_RST_CPU_HOLD		0x1010
+
+/*
+ * Write the kernel entry point for secondary CPUs to the specified address
+ */
+static void write_release_addr(u32 release_phys)
+{
+	u32 *virt = (u32 *) phys_to_virt(release_phys);
+	writel_relaxed(virt_to_phys(secondary_startup), virt);
+	/* Make sure this store is visible to other CPUs */
+	smp_wmb();
+	__cpuc_flush_dcache_area(virt, sizeof(u32));
+}
+
+static int axxia_boot_secondary(unsigned int cpu, struct task_struct *idle)
+{
+	struct device_node *syscon_np;
+	void __iomem *syscon;
+	u32 tmp;
+
+	syscon_np = of_find_compatible_node(NULL, NULL, "lsi,axxia-syscon");
+	if (!syscon_np)
+		return -ENOENT;
+
+	syscon = of_iomap(syscon_np, 0);
+	if (!syscon)
+		return -ENOMEM;
+
+	tmp = readl(syscon + SC_RST_CPU_HOLD);
+	writel(0xab, syscon + SC_CRIT_WRITE_KEY);
+	tmp &= ~(1 << cpu);
+	writel(tmp, syscon + SC_RST_CPU_HOLD);
+
+	return 0;
+}
+
+static void __init axxia_smp_prepare_cpus(unsigned int max_cpus)
+{
+	int cpu_count = 0;
+	int cpu;
+
+	/*
+	 * Initialise the present map, which describes the set of CPUs actually
+	 * populated at the present time.
+	 */
+	for_each_possible_cpu(cpu) {
+		struct device_node *np;
+		u32 release_phys;
+
+		np = of_get_cpu_node(cpu, NULL);
+		if (!np)
+			continue;
+		if (of_property_read_u32(np, "cpu-release-addr", &release_phys))
+			continue;
+
+		if (cpu_count < max_cpus) {
+			set_cpu_present(cpu, true);
+			cpu_count++;
+		}
+
+		if (release_phys != 0)
+			write_release_addr(release_phys);
+	}
+}
+
+static struct smp_operations axxia_smp_ops __initdata = {
+	.smp_prepare_cpus	= axxia_smp_prepare_cpus,
+	.smp_boot_secondary	= axxia_boot_secondary,
+};
+CPU_METHOD_OF_DECLARE(axxia_smp, "lsi,syscon-release", &axxia_smp_ops);