[PATCH v3] watchdog: Add a watchdog driver for Raspberry Pi boards
Stefan Roese
sr at denx.de
Thu Jan 26 07:28:40 CET 2023
On 1/25/23 10:57, ETIENNE DUBLE wrote:
> This driver supports the bcm2835 watchdog found on
> Raspberry Pi boards.
> It is derived from the Linux driver and was tested
> on two Raspberry Pi board versions (B+ and 3B+).
>
> Signed-off-by: Etienne Dublé <etienne.duble at imag.fr>
Reviewed-by: Stefan Roese <sr at denx.de>
Thanks,
Stefan
> ---
> Changes for v2:
> - fixed whitespaces in email
> - moved a static variable to the priv struct
> Changes for v3:
> - used the max timeout value the hardware supports
> - turned the warning to a one-line message
>
> drivers/watchdog/Kconfig | 9 +++
> drivers/watchdog/Makefile | 1 +
> drivers/watchdog/bcm2835_wdt.c | 132 +++++++++++++++++++++++++++++++++
> 3 files changed, 142 insertions(+)
> create mode 100644 drivers/watchdog/bcm2835_wdt.c
>
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index f1b1cf63ca..06c0d630c8 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -30,6 +30,7 @@ config WATCHDOG_TIMEOUT_MSECS
> default 128000 if ARCH_MX7 || ARCH_VF610
> default 30000 if ARCH_SOCFPGA
> default 16000 if ARCH_SUNXI
> + default 15000 if ARCH_BCM283X
> default 60000
> help
> Watchdog timeout in msec
> @@ -326,6 +327,14 @@ config WDT_SUNXI
> help
> Enable support for the watchdog timer in Allwinner sunxi SoCs.
>
> +config WDT_BCM2835
> + bool "Broadcom 2835 watchdog timer support"
> + depends on WDT && ARCH_BCM283X
> + default y
> + help
> + Enable support for the watchdog timer in Broadcom 283X SoCs such
> + as Raspberry Pi boards.
> +
> config XILINX_TB_WATCHDOG
> bool "Xilinx Axi watchdog timer support"
> depends on WDT
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index 446d961d7d..f99915960c 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -21,6 +21,7 @@ obj-$(CONFIG_WDT_APPLE) += apple_wdt.o
> obj-$(CONFIG_WDT_ARMADA_37XX) += armada-37xx-wdt.o
> obj-$(CONFIG_WDT_ASPEED) += ast_wdt.o
> obj-$(CONFIG_WDT_AST2600) += ast2600_wdt.o
> +obj-$(CONFIG_WDT_BCM2835) += bcm2835_wdt.o
> obj-$(CONFIG_WDT_BCM6345) += bcm6345_wdt.o
> obj-$(CONFIG_WDT_BOOKE) += booke_wdt.o
> obj-$(CONFIG_WDT_CORTINA) += cortina_wdt.o
> diff --git a/drivers/watchdog/bcm2835_wdt.c b/drivers/watchdog/bcm2835_wdt.c
> new file mode 100644
> index 0000000000..3c1ead3dda
> --- /dev/null
> +++ b/drivers/watchdog/bcm2835_wdt.c
> @@ -0,0 +1,132 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (C) 2013 Lubomir Rintel <lkundrak at v3.sk>
> + * Copyright (C) 2023 Etienne Dublé (CNRS) <etienne.duble at imag.fr>
> + *
> + * This code is mostly derived from the linux driver.
> + */
> +
> +#include <dm.h>
> +#include <wdt.h>
> +#include <asm/io.h>
> +#include <linux/delay.h>
> +
> +#define PM_RSTC 0x1c
> +#define PM_WDOG 0x24
> +
> +#define PM_PASSWORD 0x5a000000
> +
> +/* The hardware supports a maximum timeout value of 0xfffff ticks
> + * (just below 16 seconds).
> + */
> +#define PM_WDOG_MAX_TICKS 0x000fffff
> +#define PM_RSTC_WRCFG_CLR 0xffffffcf
> +#define PM_RSTC_WRCFG_FULL_RESET 0x00000020
> +#define PM_RSTC_RESET 0x00000102
> +
> +#define MS_TO_WDOG_TICKS(x) (((x) << 16) / 1000)
> +
> +struct bcm2835_wdt_priv {
> + void __iomem *base;
> + u64 timeout_ticks;
> +};
> +
> +static int bcm2835_wdt_start_ticks(struct udevice *dev,
> + u64 timeout_ticks, ulong flags)
> +{
> + struct bcm2835_wdt_priv *priv = dev_get_priv(dev);
> + void __iomem *base = priv->base;
> + u32 cur;
> +
> + writel(PM_PASSWORD | timeout_ticks, base + PM_WDOG);
> + cur = readl(base + PM_RSTC);
> + writel(PM_PASSWORD | (cur & PM_RSTC_WRCFG_CLR) | PM_RSTC_WRCFG_FULL_RESET,
> + base + PM_RSTC);
> +
> + return 0;
> +}
> +
> +static int bcm2835_wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags)
> +{
> + struct bcm2835_wdt_priv *priv = dev_get_priv(dev);
> +
> + priv->timeout_ticks = MS_TO_WDOG_TICKS(timeout_ms);
> +
> + if (priv->timeout_ticks > PM_WDOG_MAX_TICKS) {
> + printf("bcm2835_wdt: the timeout value is too high, using ~16s instead.\n");
> + priv->timeout_ticks = PM_WDOG_MAX_TICKS;
> + }
> +
> + return bcm2835_wdt_start_ticks(dev, priv->timeout_ticks, flags);
> +}
> +
> +static int bcm2835_wdt_reset(struct udevice *dev)
> +{
> + struct bcm2835_wdt_priv *priv = dev_get_priv(dev);
> +
> + /* restart the timer with the value of priv->timeout_ticks
> + * saved from the last bcm2835_wdt_start() call.
> + */
> + return bcm2835_wdt_start_ticks(dev, priv->timeout_ticks, 0);
> +}
> +
> +static int bcm2835_wdt_stop(struct udevice *dev)
> +{
> + struct bcm2835_wdt_priv *priv = dev_get_priv(dev);
> + void __iomem *base = priv->base;
> +
> + writel(PM_PASSWORD | PM_RSTC_RESET, base + PM_RSTC);
> +
> + return 0;
> +}
> +
> +static int bcm2835_wdt_expire_now(struct udevice *dev, ulong flags)
> +{
> + int ret;
> +
> + /* use a timeout of 10 ticks (~150us) */
> + ret = bcm2835_wdt_start_ticks(dev, 10, flags);
> + if (ret)
> + return ret;
> +
> + mdelay(500);
> +
> + return 0;
> +}
> +
> +static const struct wdt_ops bcm2835_wdt_ops = {
> + .reset = bcm2835_wdt_reset,
> + .start = bcm2835_wdt_start,
> + .stop = bcm2835_wdt_stop,
> + .expire_now = bcm2835_wdt_expire_now,
> +};
> +
> +static const struct udevice_id bcm2835_wdt_ids[] = {
> + { .compatible = "brcm,bcm2835-pm" },
> + { .compatible = "brcm,bcm2835-pm-wdt" },
> + { /* sentinel */ }
> +};
> +
> +static int bcm2835_wdt_probe(struct udevice *dev)
> +{
> + struct bcm2835_wdt_priv *priv = dev_get_priv(dev);
> +
> + priv->base = dev_remap_addr(dev);
> + if (!priv->base)
> + return -EINVAL;
> +
> + priv->timeout_ticks = PM_WDOG_MAX_TICKS;
> +
> + bcm2835_wdt_stop(dev);
> +
> + return 0;
> +}
> +
> +U_BOOT_DRIVER(bcm2835_wdt) = {
> + .name = "bcm2835_wdt",
> + .id = UCLASS_WDT,
> + .of_match = bcm2835_wdt_ids,
> + .probe = bcm2835_wdt_probe,
> + .priv_auto = sizeof(struct bcm2835_wdt_priv),
> + .ops = &bcm2835_wdt_ops,
> +};
Viele Grüße,
Stefan Roese
--
DENX Software Engineering GmbH, Managing Director: Erika Unter
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-51 Fax: (+49)-8142-66989-80 Email: sr at denx.de
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