linux/arch/arm/mach-mvebu/system-controller.c

/*
 * System controller support for Armada 370 and XP platforms.
 *
 * Copyright (C) 2012 Marvell
 *
 * Lior Amsalem <alior@marvell.com>
 * Gregory CLEMENT <gregory.clement@free-electrons.com>
 * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2.  This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 *
 * The Armada 370 and Armada XP SoCs both have a range of
 * miscellaneous registers, that do not belong to a particular device,
 * but rather provide system-level features. This basic
 * system-controller driver provides a device tree binding for those
 * registers, and implements utility functions offering various
 * features related to those registers.
 *
 * For now, the feature set is limited to restarting the platform by a
 * soft-reset, but it might be extended in the future.
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/of_address.h>
#include <linux/io.h>
#include <linux/reboot.h>

static void __iomem *system_controller_base;

struct mvebu_system_controller {
	u32 rstoutn_mask_offset;
	u32 system_soft_reset_offset;

	u32 rstoutn_mask_reset_out_en;
	u32 system_soft_reset;
};
static struct mvebu_system_controller *mvebu_sc;

const struct mvebu_system_controller armada_370_xp_system_controller = {
	.rstoutn_mask_offset = 0x60,
	.system_soft_reset_offset = 0x64,
	.rstoutn_mask_reset_out_en = 0x1,
	.system_soft_reset = 0x1,
};

const struct mvebu_system_controller orion_system_controller = {
	.rstoutn_mask_offset = 0x108,
	.system_soft_reset_offset = 0x10c,
	.rstoutn_mask_reset_out_en = 0x4,
	.system_soft_reset = 0x1,
};

static struct of_device_id of_system_controller_table[] = {
	{
		.compatible = "marvell,orion-system-controller",
		.data = (void *) &orion_system_controller,
	}, {
		.compatible = "marvell,armada-370-xp-system-controller",
		.data = (void *) &armada_370_xp_system_controller,
	},
	{ /* end of list */ },
};

void mvebu_restart(enum reboot_mode mode, const char *cmd)
{
	if (!system_controller_base) {
		pr_err("Cannot restart, system-controller not available: check the device tree\n");
	} else {
		/*
		 * Enable soft reset to assert RSTOUTn.
		 */
		writel(mvebu_sc->rstoutn_mask_reset_out_en,
			system_controller_base +
			mvebu_sc->rstoutn_mask_offset);
		/*
		 * Assert soft reset.
		 */
		writel(mvebu_sc->system_soft_reset,
			system_controller_base +
			mvebu_sc->system_soft_reset_offset);
	}

	while (1)
		;
}

static int __init mvebu_system_controller_init(void)
{
	struct device_node *np;

	np = of_find_matching_node(NULL, of_system_controller_table);
	if (np) {
		const struct of_device_id *match =
		    of_match_node(of_system_controller_table, np);
		BUG_ON(!match);
		system_controller_base = of_iomap(np, 0);
		mvebu_sc = (struct mvebu_system_controller *)match->data;
		of_node_put(np);
	}

	return 0;
}

arch_initcall(mvebu_system_controller_init);