ARM: UniPhier: add basic support for UniPhier architecture

Initial commit for a new SoC family, UniPhier, developed by
Socionext Inc. (formerly, System LSI Business Division of
Panasonic Corporation).

This commit includes a minimal set of components for booting the
kernel, including SMP support.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 90 insertions, 0 deletions

diff --git a/arch/arm/mach-uniphier/platsmp.c b/arch/arm/mach-uniphier/platsmp.c
new file mode 100644
index 000000000000..5943e1cb7fe1
--- /dev/null
+++ b/arch/arm/mach-uniphier/platsmp.c
@@ -0,0 +1,90 @@
+/*
+ * Copyright (C) 2015 Masahiro Yamada <yamada.masahiro@socionext.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/sizes.h>
+#include <linux/compiler.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/regmap.h>
+#include <linux/mfd/syscon.h>
+#include <asm/smp.h>
+#include <asm/smp_scu.h>
+
+static struct regmap *sbcm_regmap;
+
+static void __init uniphier_smp_prepare_cpus(unsigned int max_cpus)
+{
+	static cpumask_t only_cpu_0 = { CPU_BITS_CPU0 };
+	unsigned long scu_base_phys = 0;
+	void __iomem *scu_base;
+
+	sbcm_regmap = syscon_regmap_lookup_by_compatible(
+			"socionext,uniphier-system-bus-controller-misc");
+	if (IS_ERR(sbcm_regmap)) {
+		pr_err("failed to regmap system-bus-controller-misc\n");
+		goto err;
+	}
+
+	if (scu_a9_has_base())
+		scu_base_phys = scu_a9_get_base();
+
+	if (!scu_base_phys) {
+		pr_err("failed to get scu base\n");
+		goto err;
+	}
+
+	scu_base = ioremap(scu_base_phys, SZ_128);
+	if (!scu_base) {
+		pr_err("failed to remap scu base (0x%08lx)\n", scu_base_phys);
+		goto err;
+	}
+
+	scu_enable(scu_base);
+	iounmap(scu_base);
+
+	return;
+err:
+	pr_warn("disabling SMP\n");
+	init_cpu_present(&only_cpu_0);
+	sbcm_regmap = NULL;
+}
+
+static void __naked uniphier_secondary_startup(void)
+{
+	asm("bl		v7_invalidate_l1\n"
+	    "b		secondary_startup\n");
+};
+
+static int uniphier_boot_secondary(unsigned int cpu,
+				   struct task_struct *idle)
+{
+	int ret;
+
+	if (!sbcm_regmap)
+		return -ENODEV;
+
+	ret = regmap_write(sbcm_regmap, 0x1208,
+			   virt_to_phys(uniphier_secondary_startup));
+	if (!ret)
+		asm("sev"); /* wake up secondary CPU */
+
+	return ret;
+}
+
+struct smp_operations uniphier_smp_ops __initdata = {
+	.smp_prepare_cpus	= uniphier_smp_prepare_cpus,
+	.smp_boot_secondary	= uniphier_boot_secondary,
+};
+CPU_METHOD_OF_DECLARE(uniphier_smp, "socionext,uniphier-smp",
+		      &uniphier_smp_ops);