arm: npcm: add basic support for Nuvoton BMCs

Adds basic support for the Nuvoton NPCM750 BMC.

Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
Reviewed-by: Tomer Maimon <tmaimon77@gmail.com>
Reviewed-by: Avi Fishman <avifishman70@gmail.com>
Tested-by: Tomer Maimon <tmaimon77@gmail.com>
Tested-by: Avi Fishman <avifishman70@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 81 insertions, 0 deletions

diff --git a/arch/arm/mach-npcm/platsmp.c b/arch/arm/mach-npcm/platsmp.c
new file mode 100644
index 000000000000..21633c70fe7f
--- /dev/null
+++ b/arch/arm/mach-npcm/platsmp.c
@@ -0,0 +1,81 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2018 Nuvoton Technology corporation.
+// Copyright 2018 Google, Inc.
+
+#define pr_fmt(fmt) "nuvoton,npcm7xx-smp: " fmt
+
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/smp.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_platform.h>
+#include <linux/of_address.h>
+#include <asm/cacheflush.h>
+#include <asm/smp.h>
+#include <asm/smp_plat.h>
+#include <asm/smp_scu.h>
+
+#define NPCM7XX_SCRPAD_REG 0x13c
+
+extern void npcm7xx_secondary_startup(void);
+
+static int npcm7xx_smp_boot_secondary(unsigned int cpu,
+				      struct task_struct *idle)
+{
+	struct device_node *gcr_np;
+	void __iomem *gcr_base;
+	int ret = 0;
+
+	gcr_np = of_find_compatible_node(NULL, NULL, "nuvoton,npcm750-gcr");
+	if (!gcr_np) {
+		pr_err("no gcr device node\n");
+		ret = -ENODEV;
+		goto out;
+	}
+	gcr_base = of_iomap(gcr_np, 0);
+	if (!gcr_base) {
+		pr_err("could not iomap gcr");
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	/* give boot ROM kernel start address. */
+	iowrite32(__pa_symbol(npcm7xx_secondary_startup), gcr_base +
+		  NPCM7XX_SCRPAD_REG);
+	/* make sure the previous write is seen by all observers. */
+	dsb_sev();
+
+	iounmap(gcr_base);
+out:
+	return ret;
+}
+
+static void __init npcm7xx_smp_prepare_cpus(unsigned int max_cpus)
+{
+	struct device_node *scu_np;
+	void __iomem *scu_base;
+
+	scu_np = of_find_compatible_node(NULL, NULL, "arm,cortex-a9-scu");
+	if (!scu_np) {
+		pr_err("no scu device node\n");
+		return;
+	}
+	scu_base = of_iomap(scu_np, 0);
+	if (!scu_base) {
+		pr_err("could not iomap scu");
+		return;
+	}
+
+	scu_enable(scu_base);
+
+	iounmap(scu_base);
+}
+
+static struct smp_operations npcm7xx_smp_ops __initdata = {
+	.smp_prepare_cpus = npcm7xx_smp_prepare_cpus,
+	.smp_boot_secondary = npcm7xx_smp_boot_secondary,
+};
+
+CPU_METHOD_OF_DECLARE(npcm7xx_smp, "nuvoton,npcm750-smp", &npcm7xx_smp_ops);