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// SPDX-License-Identifier: GPL-2.0+
/*
* Socfpga Reset Controller Driver
*
* Copyright 2014 Steffen Trumtrar <s.trumtrar@pengutronix.de>
*
* based on
* Allwinner SoCs Reset Controller driver
*
* Copyright 2013 Maxime Ripard
*
* Maxime Ripard <maxime.ripard@free-electrons.com>
*/
#include <common.h>
#include <dm.h>
#include <dm/of_access.h>
#include <reset-uclass.h>
#include <linux/bitops.h>
#include <linux/io.h>
#include <linux/sizes.h>
#define BANK_INCREMENT 4
#define NR_BANKS 8
struct socfpga_reset_data {
void __iomem *modrst_base;
};
/*
* For compatibility with Kernels that don't support peripheral reset, this
* driver can keep the old behaviour of not asserting peripheral reset before
* starting the OS and deasserting all peripheral resets (enabling all
* peripherals).
*
* For that, the reset driver checks the environment variable
* "socfpga_legacy_reset_compat". If this variable is '1', perihperals are not
* reset again once taken out of reset and all peripherals in 'permodrst' are
* taken out of reset before booting into the OS.
* Note that this should be required for gen5 systems only that are running
* Linux kernels without proper peripheral reset support for all drivers used.
*/
static bool socfpga_reset_keep_enabled(void)
{
#if !defined(CONFIG_SPL_BUILD) || CONFIG_IS_ENABLED(ENV_SUPPORT)
const char *env_str;
long val;
env_str = env_get("socfpga_legacy_reset_compat");
if (env_str) {
val = simple_strtol(env_str, NULL, 0);
if (val == 1)
return true;
}
#endif
return false;
}
static int socfpga_reset_assert(struct reset_ctl *reset_ctl)
{
struct socfpga_reset_data *data = dev_get_priv(reset_ctl->dev);
int id = reset_ctl->id;
int reg_width = sizeof(u32);
int bank = id / (reg_width * BITS_PER_BYTE);
int offset = id % (reg_width * BITS_PER_BYTE);
setbits_le32(data->modrst_base + (bank * BANK_INCREMENT), BIT(offset));
return 0;
}
static int socfpga_reset_deassert(struct reset_ctl *reset_ctl)
{
struct socfpga_reset_data *data = dev_get_priv(reset_ctl->dev);
int id = reset_ctl->id;
int reg_width = sizeof(u32);
int bank = id / (reg_width * BITS_PER_BYTE);
int offset = id % (reg_width * BITS_PER_BYTE);
clrbits_le32(data->modrst_base + (bank * BANK_INCREMENT), BIT(offset));
return 0;
}
static int socfpga_reset_request(struct reset_ctl *reset_ctl)
{
debug("%s(reset_ctl=%p) (dev=%p, id=%lu)\n", __func__,
reset_ctl, reset_ctl->dev, reset_ctl->id);
return 0;
}
static int socfpga_reset_free(struct reset_ctl *reset_ctl)
{
debug("%s(reset_ctl=%p) (dev=%p, id=%lu)\n", __func__, reset_ctl,
reset_ctl->dev, reset_ctl->id);
return 0;
}
static const struct reset_ops socfpga_reset_ops = {
.request = socfpga_reset_request,
.free = socfpga_reset_free,
.rst_assert = socfpga_reset_assert,
.rst_deassert = socfpga_reset_deassert,
};
static int socfpga_reset_probe(struct udevice *dev)
{
struct socfpga_reset_data *data = dev_get_priv(dev);
u32 modrst_offset;
void __iomem *membase;
membase = devfdt_get_addr_ptr(dev);
modrst_offset = dev_read_u32_default(dev, "altr,modrst-offset", 0x10);
data->modrst_base = membase + modrst_offset;
return 0;
}
static int socfpga_reset_remove(struct udevice *dev)
{
struct socfpga_reset_data *data = dev_get_priv(dev);
if (socfpga_reset_keep_enabled()) {
puts("Deasserting all peripheral resets\n");
writel(0, data->modrst_base + 4);
}
return 0;
}
static const struct udevice_id socfpga_reset_match[] = {
{ .compatible = "altr,rst-mgr" },
{ /* sentinel */ },
};
U_BOOT_DRIVER(socfpga_reset) = {
.name = "socfpga-reset",
.id = UCLASS_RESET,
.of_match = socfpga_reset_match,
.probe = socfpga_reset_probe,
.priv_auto_alloc_size = sizeof(struct socfpga_reset_data),
.ops = &socfpga_reset_ops,
.remove = socfpga_reset_remove,
.flags = DM_FLAG_OS_PREPARE,
};
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