drivers/reset/reset-sunxi.c

// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
/*
 * Copyright (C) 2018 Amarula Solutions.
 * Author: Jagan Teki <jagan@amarulasolutions.com>
 */

#include <dm.h>
#include <errno.h>
#include <log.h>
#include <malloc.h>
#include <reset-uclass.h>
#include <asm/io.h>
#include <clk/sunxi.h>
#include <linux/bitops.h>
#include <linux/log2.h>

static const struct ccu_reset *plat_to_reset(struct ccu_plat *plat,
					     unsigned long id)
{
	return	&plat->desc->resets[id];
}

static int sunxi_reset_request(struct reset_ctl *reset_ctl)
{
	struct ccu_plat *plat = dev_get_plat(reset_ctl->dev);

	debug("%s: (RST#%ld)\n", __func__, reset_ctl->id);

	if (reset_ctl->id >= plat->desc->num_resets)
		return -EINVAL;

	return 0;
}

static int sunxi_set_reset(struct reset_ctl *reset_ctl, bool on)
{
	struct ccu_plat *plat = dev_get_plat(reset_ctl->dev);
	const struct ccu_reset *reset = plat_to_reset(plat, reset_ctl->id);
	u32 reg;

	if (!(reset->flags & CCU_RST_F_IS_VALID)) {
		printf("%s: (RST#%ld) unhandled\n", __func__, reset_ctl->id);
		return 0;
	}

	debug("%s: (RST#%ld) off#0x%x, BIT(%d)\n", __func__,
	      reset_ctl->id, reset->off, ilog2(reset->bit));

	reg = readl(plat->base + reset->off);
	if (on)
		reg |= reset->bit;
	else
		reg &= ~reset->bit;

	writel(reg, plat->base + reset->off);

	return 0;
}

static int sunxi_reset_assert(struct reset_ctl *reset_ctl)
{
	return sunxi_set_reset(reset_ctl, false);
}

static int sunxi_reset_deassert(struct reset_ctl *reset_ctl)
{
	return sunxi_set_reset(reset_ctl, true);
}

struct reset_ops sunxi_reset_ops = {
	.request = sunxi_reset_request,
	.rst_assert = sunxi_reset_assert,
	.rst_deassert = sunxi_reset_deassert,
};

U_BOOT_DRIVER(sunxi_reset) = {
	.name		= "sunxi_reset",
	.id		= UCLASS_RESET,
	.ops		= &sunxi_reset_ops,
};