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51443c9a49
The udelay() function in lib/time.c contains a WATCHDOG_RESET()
call. The only reason this doesn't lead to a catastrophic infinite
recursion is due to the rate-limiting in wdt-uclass.c:
if (time_after_eq(now, priv->next_reset)) {
priv->next_reset = now + priv->reset_period;
wdt_reset(dev);
}
But this would fall apart if ->next_reset was updated after calling the
device's reset method.
This is needlessly fragile, and it's easy enough to avoid that
recursion in the first place by just using __udelay() directly.
Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Reviewed-by: Stefan Roese <sr@denx.de>
97 lines
1.9 KiB
C
97 lines
1.9 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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#include <dm.h>
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#include <dm/device_compat.h>
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#include <wdt.h>
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#include <asm/gpio.h>
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#include <linux/delay.h>
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enum {
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HW_ALGO_TOGGLE,
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HW_ALGO_LEVEL,
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};
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struct gpio_wdt_priv {
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struct gpio_desc gpio;
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unsigned int hw_algo;
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bool always_running;
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int state;
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};
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static int gpio_wdt_reset(struct udevice *dev)
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{
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struct gpio_wdt_priv *priv = dev_get_priv(dev);
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switch (priv->hw_algo) {
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case HW_ALGO_TOGGLE:
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/* Toggle output pin */
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priv->state = !priv->state;
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dm_gpio_set_value(&priv->gpio, priv->state);
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break;
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case HW_ALGO_LEVEL:
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/* Pulse */
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dm_gpio_set_value(&priv->gpio, 1);
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__udelay(1);
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dm_gpio_set_value(&priv->gpio, 0);
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break;
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}
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return 0;
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}
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static int gpio_wdt_start(struct udevice *dev, u64 timeout, ulong flags)
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{
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struct gpio_wdt_priv *priv = dev_get_priv(dev);
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if (priv->always_running)
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return 0;
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return -ENOSYS;
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}
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static int dm_probe(struct udevice *dev)
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{
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struct gpio_wdt_priv *priv = dev_get_priv(dev);
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int ret;
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const char *algo = dev_read_string(dev, "hw_algo");
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if (!algo)
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return -EINVAL;
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if (!strcmp(algo, "toggle"))
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priv->hw_algo = HW_ALGO_TOGGLE;
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else if (!strcmp(algo, "level"))
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priv->hw_algo = HW_ALGO_LEVEL;
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else
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return -EINVAL;
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priv->always_running = dev_read_bool(dev, "always-running");
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ret = gpio_request_by_name(dev, "gpios", 0, &priv->gpio, GPIOD_IS_OUT);
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if (ret < 0) {
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dev_err(dev, "Request for wdt gpio failed: %d\n", ret);
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return ret;
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}
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if (priv->always_running)
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ret = gpio_wdt_reset(dev);
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return ret;
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}
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static const struct wdt_ops gpio_wdt_ops = {
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.start = gpio_wdt_start,
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.reset = gpio_wdt_reset,
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};
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static const struct udevice_id gpio_wdt_ids[] = {
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{ .compatible = "linux,wdt-gpio" },
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{}
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};
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U_BOOT_DRIVER(wdt_gpio) = {
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.name = "wdt_gpio",
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.id = UCLASS_WDT,
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.of_match = gpio_wdt_ids,
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.ops = &gpio_wdt_ops,
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.probe = dm_probe,
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.priv_auto = sizeof(struct gpio_wdt_priv),
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};
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