Re: [PATCH 1/5] drivers: watchdog: add mcf watchdog support

Stefan Roese
2023-07-18T12:23:15Z

On 6/25/23 21:35, Angelo Dureghello wrote:
> This watchdog driver applies to the following
> mcf families:
>
> - mcf52x2 (5271 5275 5282)
> - mcf532x (5329 5373)
> - mcf523x (5235)
>
> Cpu's not listed for each family does not have WDT module.
>
> Note, after some attempts testing by qemu on 5208 i
> finally abandoned, watchdog seems not implemented properly.
>
> The driver has been tested in a real M5282EVM.
>
> Signed-off-by: Angelo Dureghello <angelo@kernel-space.org>
> ---
> drivers/watchdog/Kconfig | 7 ++
> drivers/watchdog/Makefile | 1 +
> drivers/watchdog/mcf_wdt.c | 162 +++++++++++++++++++++++++++++++++++++
> 3 files changed, 170 insertions(+)
> create mode 100644 drivers/watchdog/mcf_wdt.c
>
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 646663528a..07fc4940e9 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -178,6 +178,13 @@ config WDT_MAX6370
> help
> Select this to enable max6370 watchdog timer.
>
> +config WDT_MCF
> + bool "ColdFire family watchdog timer support"
> + depends on WDT
> + help
> + Select this to enable ColdFire watchdog timer,
> + which supports mcf52x2 mcf532x mcf523x families.
> +
> config WDT_MESON_GXBB
> bool "Amlogic watchdog timer support"
> depends on WDT
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index fd5d9c7376..eef786f5e7 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -31,6 +31,7 @@ obj-$(CONFIG_WDT_CDNS) += cdns_wdt.o
> obj-$(CONFIG_WDT_FTWDT010) += ftwdt010_wdt.o
> obj-$(CONFIG_WDT_GPIO) += gpio_wdt.o
> obj-$(CONFIG_WDT_MAX6370) += max6370_wdt.o
> +obj-$(CONFIG_WDT_MCF) += mcf_wdt.o
> obj-$(CONFIG_WDT_MESON_GXBB) += meson_gxbb_wdt.o
> obj-$(CONFIG_WDT_MPC8xxx) += mpc8xxx_wdt.o
> obj-$(CONFIG_WDT_MT7620) += mt7620_wdt.o
> diff --git a/drivers/watchdog/mcf_wdt.c b/drivers/watchdog/mcf_wdt.c
> new file mode 100644
> index 0000000000..03842135c5
> --- /dev/null
> +++ b/drivers/watchdog/mcf_wdt.c
> @@ -0,0 +1,162 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * mcf_wdt.c - driver for ColdFire on-chip watchdog
> + *
> + * Author: Angelo Dureghello <angelo@kernel-space.org>
> + *
> + */
> +
> +#include <common.h>
> +#include <dm.h>
> +#include <hang.h>
> +#include <asm/io.h>
> +#include <wdt.h>
> +#include <linux/bitops.h>
> +
> +#define TIMEOUT_MAX 3360
> +#define TIMEOUT_MIN 500

Those 2 defines above are not used in this source. Please drop.

> +
> +#define DIVIDER_5XXX 4096
> +#define DIVIDER_5282 8192
> +
> +#define WCR_EN BIT(0)
> +#define WCR_HALTED BIT(1)
> +#define WCR_DOZE BIT(2)
> +#define WCR_WAIT BIT(3)
> +
> +struct watchdog_regs {
> + u16 wcr; /* Control */
> + u16 wmr; /* Service */
> + u16 wcntr; /* Counter */
> + u16 wsr; /* Reset Status */
> +};
> +
> +#if defined(CONFIG_WDT_MCF)

Is it possible to drop this "#if" somehow?

> +static void mcf_watchdog_reset(struct watchdog_regs *wdog)
> +{
> +#ifndef CONFIG_WATCHDOG_RESET_DISABLE
> + writew(0x5555, &wdog->wsr);
> + writew(0xaaaa, &wdog->wsr);
> +#endif /* CONFIG_WATCHDOG_RESET_DISABLE*/

checkpatch.pl warning:

WARNING: Use 'if (IS_ENABLED(CONFIG...))' instead of '#if or #ifdef'
where possible
#37: FILE: drivers/watchdog/mcf_wdt.c:37:
+#ifndef CONFIG_WATCHDOG_RESET_DISABLE

> +}
> +
> +static void mcf_watchdog_init(struct watchdog_regs *wdog, u32 fixed_divider,
> + u64 timeout_msecs)
> +{
> + u32 wdog_module;
> +
> + /*
> + * The timer watchdog can be set between
> + * 0.5 and 128 Seconds.
> + */
> +
> + /* set timeout and enable watchdog */
> + wdog_module = ((CFG_SYS_CLK / 1000) * timeout_msecs);
> +
> + writew((u16)(wdog_module / fixed_divider), &wdog->wmr);
> + writew(WCR_EN, &wdog->wcr);
> +
> + mcf_watchdog_reset(wdog);
> +}
> +
> +#if !CONFIG_IS_ENABLED(WDT)
> +void hw_watchdog_reset(void)
> +{
> + struct watchdog_regs *wdog = (struct watchdog_regs *)MMAP_WDOG;
> +
> + mcf_watchdog_reset(wdog);
> +}

Can you perhaps completely remove this hw_watchdog stuff? Is it really
needed on these Coldfire platforms?

> +
> +void hw_watchdog_init(void)
> +{
> + struct watchdog_regs *wdog = (struct watchdog_regs *)MMAP_WDOG;
> +
> + if (IS_ENABLED(CONFIG_MCF5282))
> + writew(&wdog->wmr, wdog_module / DIVIDER_5282);
> + else
> + writew(&wdog->wmr, wdog_module / DIVIDER_5XXX);
> +
> + mcf_watchdog_init(wdog, CONFIG_WATCHDOG_TIMEOUT_MSECS);
> +}
> +
> +#else /* CONFIG_WDT */
> +
> +struct mcf_wdt_priv {
> + void __iomem *base;
> + u32 fixed_divider;
> +};
> +
> +static int mcf_wdt_expire_now(struct udevice *dev, ulong flags)
> +{
> + hang();
> +
> + return 0;
> +}
> +
> +static int mcf_wdt_reset(struct udevice *dev)
> +{
> + struct mcf_wdt_priv *priv = dev_get_priv(dev);
> +
> + mcf_watchdog_reset(priv->base);
> +
> + return 0;
> +}
> +
> +static int mcf_wdt_start(struct udevice *dev, u64 timeout, ulong flags)
> +{
> + struct mcf_wdt_priv *priv = dev_get_priv(dev);
> +
> + /* Timeout from fdt is in second, driver works in msecs */

I'm a bit confused here. AFAIK, the time passed into the start()
function is in ms:

/*
* Start the timer
*
* @dev: WDT Device
* @timeout_ms: Number of ticks (milliseconds) before timer expires
* @flags: Driver specific flags. This might be used to specify
* which action needs to be executed when the timer expires
* @return: 0 if OK, -ve on error
*/
int wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags);

So there should be no need to convert to ms here in this
function. Please double-check here again.

Thanks,
Stefan

> + mcf_watchdog_init(priv->base, priv->fixed_divider,
> + timeout * 1000);
> +
> + return 0;
> +}
> +
> +static int mcf_wdt_stop(struct udevice *dev)
> +{
> + struct mcf_wdt_priv *priv = dev_get_priv(dev);
> + struct watchdog_regs *wdog = (struct watchdog_regs *)priv->base;
> +
> + setbits_be16(&wdog->wcr, WCR_HALTED);
> +
> + return 0;
> +}
> +
> +static int mcf_wdt_probe(struct udevice *dev)
> +{
> + struct mcf_wdt_priv *priv = dev_get_priv(dev);
> +
> + priv->base = dev_read_addr_ptr(dev);
> + if (!priv->base)
> + return -ENOENT;
> +
> + priv->fixed_divider = (u32)dev_get_driver_data(dev);
> +
> + return 0;
> +}
> +
> +static const struct wdt_ops mcf_wdt_ops = {
> + .start = mcf_wdt_start,
> + .stop = mcf_wdt_stop,
> + .reset = mcf_wdt_reset,
> + .expire_now = mcf_wdt_expire_now,
> +};
> +
> +static const struct udevice_id mcf_wdt_ids[] = {
> + { .compatible = "fsl,mcf5208-wdt", .data = DIVIDER_5XXX },
> + { .compatible = "fsl,mcf5282-wdt", .data = DIVIDER_5282 },
> + {}
> +};
> +
> +U_BOOT_DRIVER(mcf_wdt) = {
> + .name = "mcf_wdt",
> + .id = UCLASS_WDT,
> + .of_match = mcf_wdt_ids,
> + .probe = mcf_wdt_probe,
> + .ops = &mcf_wdt_ops,
> + .priv_auto = sizeof(struct mcf_wdt_priv),
> + .flags = DM_FLAG_PRE_RELOC,
> +};
> +#endif
> +#endif