u-boot/drivers/watchdog/sunxi_wdt.c
Samuel Holland 93d34faeda watchdog: Add a driver for the sunxi watchdog
This driver supports the sun4i/sun6i/sun20i watchdog timers.
They have a maximum timeout of 16 seconds.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
2021-10-25 14:54:26 +01:00

188 lines
3.9 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Derived from linux/drivers/watchdog/sunxi_wdt.c:
* Copyright (C) 2013 Carlo Caione
* Copyright (C) 2012 Henrik Nordstrom
*/
#include <dm.h>
#include <wdt.h>
#include <asm/io.h>
#include <linux/delay.h>
#define MSEC_PER_SEC 1000
#define WDT_MAX_TIMEOUT 16
#define WDT_TIMEOUT_MASK 0xf
#define WDT_CTRL_RELOAD ((1 << 0) | (0x0a57 << 1))
#define WDT_MODE_EN BIT(0)
struct sunxi_wdt_reg {
u8 wdt_ctrl;
u8 wdt_cfg;
u8 wdt_mode;
u8 wdt_timeout_shift;
u8 wdt_reset_mask;
u8 wdt_reset_val;
u32 wdt_key_val;
};
struct sunxi_wdt_priv {
void __iomem *base;
const struct sunxi_wdt_reg *regs;
};
/* Map of timeout in seconds to register value */
static const u8 wdt_timeout_map[1 + WDT_MAX_TIMEOUT] = {
[0] = 0x0,
[1] = 0x1,
[2] = 0x2,
[3] = 0x3,
[4] = 0x4,
[5] = 0x5,
[6] = 0x6,
[7] = 0x7,
[8] = 0x7,
[9] = 0x8,
[10] = 0x8,
[11] = 0x9,
[12] = 0x9,
[13] = 0xa,
[14] = 0xa,
[15] = 0xb,
[16] = 0xb,
};
static int sunxi_wdt_reset(struct udevice *dev)
{
struct sunxi_wdt_priv *priv = dev_get_priv(dev);
const struct sunxi_wdt_reg *regs = priv->regs;
void __iomem *base = priv->base;
writel(WDT_CTRL_RELOAD, base + regs->wdt_ctrl);
return 0;
}
static int sunxi_wdt_start(struct udevice *dev, u64 timeout, ulong flags)
{
struct sunxi_wdt_priv *priv = dev_get_priv(dev);
const struct sunxi_wdt_reg *regs = priv->regs;
void __iomem *base = priv->base;
u32 val;
timeout /= MSEC_PER_SEC;
if (timeout > WDT_MAX_TIMEOUT)
timeout = WDT_MAX_TIMEOUT;
/* Set system reset function */
val = readl(base + regs->wdt_cfg);
val &= ~regs->wdt_reset_mask;
val |= regs->wdt_reset_val;
val |= regs->wdt_key_val;
writel(val, base + regs->wdt_cfg);
/* Set timeout and enable watchdog */
val = readl(base + regs->wdt_mode);
val &= ~(WDT_TIMEOUT_MASK << regs->wdt_timeout_shift);
val |= wdt_timeout_map[timeout] << regs->wdt_timeout_shift;
val |= WDT_MODE_EN;
val |= regs->wdt_key_val;
writel(val, base + regs->wdt_mode);
return sunxi_wdt_reset(dev);
}
static int sunxi_wdt_stop(struct udevice *dev)
{
struct sunxi_wdt_priv *priv = dev_get_priv(dev);
const struct sunxi_wdt_reg *regs = priv->regs;
void __iomem *base = priv->base;
writel(regs->wdt_key_val, base + regs->wdt_mode);
return 0;
}
static int sunxi_wdt_expire_now(struct udevice *dev, ulong flags)
{
int ret;
ret = sunxi_wdt_start(dev, 0, flags);
if (ret)
return ret;
mdelay(500);
return 0;
}
static const struct wdt_ops sunxi_wdt_ops = {
.reset = sunxi_wdt_reset,
.start = sunxi_wdt_start,
.stop = sunxi_wdt_stop,
.expire_now = sunxi_wdt_expire_now,
};
static const struct sunxi_wdt_reg sun4i_wdt_reg = {
.wdt_ctrl = 0x00,
.wdt_cfg = 0x04,
.wdt_mode = 0x04,
.wdt_timeout_shift = 3,
.wdt_reset_mask = 0x2,
.wdt_reset_val = 0x2,
};
static const struct sunxi_wdt_reg sun6i_wdt_reg = {
.wdt_ctrl = 0x10,
.wdt_cfg = 0x14,
.wdt_mode = 0x18,
.wdt_timeout_shift = 4,
.wdt_reset_mask = 0x3,
.wdt_reset_val = 0x1,
};
static const struct sunxi_wdt_reg sun20i_wdt_reg = {
.wdt_ctrl = 0x10,
.wdt_cfg = 0x14,
.wdt_mode = 0x18,
.wdt_timeout_shift = 4,
.wdt_reset_mask = 0x03,
.wdt_reset_val = 0x01,
.wdt_key_val = 0x16aa0000,
};
static const struct udevice_id sunxi_wdt_ids[] = {
{ .compatible = "allwinner,sun4i-a10-wdt", .data = (ulong)&sun4i_wdt_reg },
{ .compatible = "allwinner,sun6i-a31-wdt", .data = (ulong)&sun6i_wdt_reg },
{ .compatible = "allwinner,sun20i-d1-wdt", .data = (ulong)&sun20i_wdt_reg },
{ /* sentinel */ }
};
static int sunxi_wdt_probe(struct udevice *dev)
{
struct sunxi_wdt_priv *priv = dev_get_priv(dev);
priv->base = dev_remap_addr(dev);
if (!priv->base)
return -EINVAL;
priv->regs = (void *)dev_get_driver_data(dev);
if (!priv->regs)
return -EINVAL;
sunxi_wdt_stop(dev);
return 0;
}
U_BOOT_DRIVER(sunxi_wdt) = {
.name = "sunxi_wdt",
.id = UCLASS_WDT,
.of_match = sunxi_wdt_ids,
.probe = sunxi_wdt_probe,
.priv_auto = sizeof(struct sunxi_wdt_priv),
.ops = &sunxi_wdt_ops,
};