u-boot/drivers/watchdog/armada-37xx-wdt.c
Marek Behún 2b69a67389 watchdog: Add support for Armada 37xx CPU watchdog
This adds support for the CPU watchdog found on Marvell Armada 37xx
SoCs.

There are 4 counters which can be set as CPU watchdog counters.
This driver uses the second counter (ID 1, counting from 0)
(Marvell's Linux also uses second counter by default).
In the future it could be adapted to use other counters, with
definition in the device tree.

Signed-off-by: Marek Behun <marek.behun@nic.cz>
Signed-off-by: Stefan Roese <sr@denx.de>
2018-05-14 10:00:15 +02:00

175 lines
3.6 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Marvell Armada 37xx SoC Watchdog Driver
*
* Marek Behun <marek.behun@nic.cz>
*/
#include <common.h>
#include <dm.h>
#include <wdt.h>
#include <asm/io.h>
#include <asm/arch/cpu.h>
#include <asm/arch/soc.h>
DECLARE_GLOBAL_DATA_PTR;
struct a37xx_wdt {
void __iomem *sel_reg;
void __iomem *reg;
ulong clk_rate;
u64 timeout;
};
/*
* We use Counter 1 for watchdog timer, because so does Marvell's Linux by
* default.
*/
#define CNTR_CTRL 0x10
#define CNTR_CTRL_ENABLE 0x0001
#define CNTR_CTRL_ACTIVE 0x0002
#define CNTR_CTRL_MODE_MASK 0x000c
#define CNTR_CTRL_MODE_ONESHOT 0x0000
#define CNTR_CTRL_PRESCALE_MASK 0xff00
#define CNTR_CTRL_PRESCALE_MIN 2
#define CNTR_CTRL_PRESCALE_SHIFT 8
#define CNTR_COUNT_LOW 0x14
#define CNTR_COUNT_HIGH 0x18
static void set_counter_value(struct a37xx_wdt *priv)
{
writel(priv->timeout & 0xffffffff, priv->reg + CNTR_COUNT_LOW);
writel(priv->timeout >> 32, priv->reg + CNTR_COUNT_HIGH);
}
static void a37xx_wdt_enable(struct a37xx_wdt *priv)
{
u32 reg = readl(priv->reg + CNTR_CTRL);
reg |= CNTR_CTRL_ENABLE;
writel(reg, priv->reg + CNTR_CTRL);
}
static void a37xx_wdt_disable(struct a37xx_wdt *priv)
{
u32 reg = readl(priv->reg + CNTR_CTRL);
reg &= ~CNTR_CTRL_ENABLE;
writel(reg, priv->reg + CNTR_CTRL);
}
static int a37xx_wdt_reset(struct udevice *dev)
{
struct a37xx_wdt *priv = dev_get_priv(dev);
if (!priv->timeout)
return -EINVAL;
a37xx_wdt_disable(priv);
set_counter_value(priv);
a37xx_wdt_enable(priv);
return 0;
}
static int a37xx_wdt_expire_now(struct udevice *dev, ulong flags)
{
struct a37xx_wdt *priv = dev_get_priv(dev);
a37xx_wdt_disable(priv);
priv->timeout = 0;
set_counter_value(priv);
a37xx_wdt_enable(priv);
return 0;
}
static int a37xx_wdt_start(struct udevice *dev, u64 ms, ulong flags)
{
struct a37xx_wdt *priv = dev_get_priv(dev);
u32 reg;
reg = readl(priv->reg + CNTR_CTRL);
if (reg & CNTR_CTRL_ACTIVE)
return -EBUSY;
/* set mode */
reg = (reg & ~CNTR_CTRL_MODE_MASK) | CNTR_CTRL_MODE_ONESHOT;
/* set prescaler to the min value */
reg &= ~CNTR_CTRL_PRESCALE_MASK;
reg |= CNTR_CTRL_PRESCALE_MIN << CNTR_CTRL_PRESCALE_SHIFT;
priv->timeout = ms * priv->clk_rate / 1000 / CNTR_CTRL_PRESCALE_MIN;
writel(reg, priv->reg + CNTR_CTRL);
set_counter_value(priv);
a37xx_wdt_enable(priv);
return 0;
}
static int a37xx_wdt_stop(struct udevice *dev)
{
struct a37xx_wdt *priv = dev_get_priv(dev);
a37xx_wdt_disable(priv);
return 0;
}
static int a37xx_wdt_probe(struct udevice *dev)
{
struct a37xx_wdt *priv = dev_get_priv(dev);
fdt_addr_t addr;
addr = dev_read_addr_index(dev, 0);
if (addr == FDT_ADDR_T_NONE)
goto err;
priv->sel_reg = (void __iomem *)addr;
addr = dev_read_addr_index(dev, 1);
if (addr == FDT_ADDR_T_NONE)
goto err;
priv->reg = (void __iomem *)addr;
priv->clk_rate = (ulong)get_ref_clk() * 1000000;
a37xx_wdt_disable(priv);
/*
* We use timer 1 as watchdog timer (because Marvell's Linux uses that
* timer as default), therefore we only set bit TIMER1_IS_WCHDOG_TIMER.
*/
writel(1 << 1, priv->sel_reg);
return 0;
err:
dev_err(dev, "no io address\n");
return -ENODEV;
}
static const struct wdt_ops a37xx_wdt_ops = {
.start = a37xx_wdt_start,
.reset = a37xx_wdt_reset,
.stop = a37xx_wdt_stop,
.expire_now = a37xx_wdt_expire_now,
};
static const struct udevice_id a37xx_wdt_ids[] = {
{ .compatible = "marvell,armada-3700-wdt" },
{}
};
U_BOOT_DRIVER(a37xx_wdt) = {
.name = "armada_37xx_wdt",
.id = UCLASS_WDT,
.of_match = a37xx_wdt_ids,
.probe = a37xx_wdt_probe,
.priv_auto_alloc_size = sizeof(struct a37xx_wdt),
.ops = &a37xx_wdt_ops,
};