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@imag.fr --- 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@v3.sk + * Copyright (C) 2023 Etienne Dublé (CNRS) etienne.duble@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, +};