u-boot/arch/arm/mach-uniphier/nand-reset.c

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// SPDX-License-Identifier: GPL-2.0 or later
/*
* Copyright (C) 2020 Socionext Inc.
* Author: Masahiro Yamada <yamada.masahiro@socionext.com>
*/
#include <linux/errno.h>
#include <dm.h>
#include <dm/uclass-internal.h>
#include <reset.h>
#include "init.h"
/*
* Assert the Denali NAND controller reset if found.
*
* On LD4, the bootstrap process starts running after power-on reset regardless
* of the boot mode, here the pin-mux is not necessarily set up for NAND, then
* the controller is stuck. Assert the controller reset here, and should be
* deasserted in the driver after the pin-mux is correctly handled. For other
* SoCs, the bootstrap runs only when the boot mode selects ONFi, but it is yet
* effective when the boot swap is on. So, the reset should be asserted anyway.
*/
void uniphier_nand_reset_assert(void)
{
struct udevice *dev;
struct reset_ctl_bulk resets;
int ret;
ret = uclass_find_first_device(UCLASS_MTD, &dev);
if (ret || !dev)
return;
/* make sure this is the Denali NAND controller */
if (strcmp(dev->driver->name, "denali-nand-dt"))
return;
ret = reset_get_bulk(dev, &resets);
if (ret)
return;
reset_assert_bulk(&resets);
}