u-boot/drivers/watchdog/meson_gxbb_wdt.c
Philippe Boos 818055fd4e watchdog: add amlogic watchdog support
Add support for hardware watchdog timer for Amlogic SoCs.
This driver has been heavily inspired by his Linux equivalent
(meson_gxbb_wdt.c).

Reviewed-by: Jerome Brunet <jbrunet@baylibre.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>

Signed-off-by: Philippe Boos <pboos@baylibre.com>
Reviewed-by: Stefan Roese <sr@denx.de>
2022-07-21 08:09:06 +02:00

136 lines
3 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (c) 2022 BayLibre, SAS.
*/
#include <clk.h>
#include <dm.h>
#include <dm/device_compat.h>
#include <reset.h>
#include <wdt.h>
#include <asm/io.h>
#include <linux/bitops.h>
#define GXBB_WDT_CTRL_REG 0x0
#define GXBB_WDT_TCNT_REG 0x8
#define GXBB_WDT_RSET_REG 0xc
#define GXBB_WDT_CTRL_SYS_RESET_NOW BIT(26)
#define GXBB_WDT_CTRL_CLKDIV_EN BIT(25)
#define GXBB_WDT_CTRL_CLK_EN BIT(24)
#define GXBB_WDT_CTRL_EE_RESET BIT(21)
#define GXBB_WDT_CTRL_EN BIT(18)
#define GXBB_WDT_CTRL_DIV_MASK GENMASK(17, 0)
#define GXBB_WDT_TCNT_SETUP_MASK GENMASK(15, 0)
struct amlogic_wdt_priv {
void __iomem *reg_base;
};
static int amlogic_wdt_set_timeout(struct udevice *dev, u64 timeout_ms)
{
struct amlogic_wdt_priv *data = dev_get_priv(dev);
if (timeout_ms > GXBB_WDT_TCNT_SETUP_MASK) {
dev_warn(dev, "%s: timeout_ms=%llu: maximum watchdog timeout exceeded\n",
__func__, timeout_ms);
timeout_ms = GXBB_WDT_TCNT_SETUP_MASK;
}
writel(timeout_ms, data->reg_base + GXBB_WDT_TCNT_REG);
return 0;
}
static int amlogic_wdt_stop(struct udevice *dev)
{
struct amlogic_wdt_priv *data = dev_get_priv(dev);
writel(readl(data->reg_base + GXBB_WDT_CTRL_REG) & ~GXBB_WDT_CTRL_EN,
data->reg_base + GXBB_WDT_CTRL_REG);
return 0;
}
static int amlogic_wdt_start(struct udevice *dev, u64 time_ms, ulong flags)
{
struct amlogic_wdt_priv *data = dev_get_priv(dev);
writel(readl(data->reg_base + GXBB_WDT_CTRL_REG) | GXBB_WDT_CTRL_EN,
data->reg_base + GXBB_WDT_CTRL_REG);
return amlogic_wdt_set_timeout(dev, time_ms);
}
static int amlogic_wdt_reset(struct udevice *dev)
{
struct amlogic_wdt_priv *data = dev_get_priv(dev);
writel(0, data->reg_base + GXBB_WDT_RSET_REG);
return 0;
}
static int amlogic_wdt_expire_now(struct udevice *dev, ulong flags)
{
struct amlogic_wdt_priv *data = dev_get_priv(dev);
writel(0, data->reg_base + GXBB_WDT_CTRL_SYS_RESET_NOW);
return 0;
}
static int amlogic_wdt_probe(struct udevice *dev)
{
struct amlogic_wdt_priv *data = dev_get_priv(dev);
int ret;
data->reg_base = dev_remap_addr(dev);
if (!data->reg_base)
return -EINVAL;
struct clk clk;
ret = clk_get_by_index(dev, 0, &clk);
if (ret)
return ret;
ret = clk_enable(&clk);
if (ret) {
clk_free(&clk);
return ret;
}
/* Setup with 1ms timebase */
writel(((clk_get_rate(&clk) / 1000) & GXBB_WDT_CTRL_DIV_MASK) |
GXBB_WDT_CTRL_EE_RESET |
GXBB_WDT_CTRL_CLK_EN |
GXBB_WDT_CTRL_CLKDIV_EN,
data->reg_base + GXBB_WDT_CTRL_REG);
return 0;
}
static const struct wdt_ops amlogic_wdt_ops = {
.start = amlogic_wdt_start,
.reset = amlogic_wdt_reset,
.stop = amlogic_wdt_stop,
.expire_now = amlogic_wdt_expire_now,
};
static const struct udevice_id amlogic_wdt_ids[] = {
{ .compatible = "amlogic,meson-gxbb-wdt" },
{}
};
U_BOOT_DRIVER(amlogic_wdt) = {
.name = "amlogic_wdt",
.id = UCLASS_WDT,
.of_match = amlogic_wdt_ids,
.priv_auto = sizeof(struct amlogic_wdt_priv),
.probe = amlogic_wdt_probe,
.ops = &amlogic_wdt_ops,
.flags = DM_FLAG_PRE_RELOC,
};