[PATCH] watchdog: Add a watchdog driver for Raspberry Pi boards
Stefan Roese
sr at denx.de
Tue Jan 24 14:38:55 CET 2023
Hi Etienne,
On 1/24/23 14:20, Etienne Dublé 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>
> ---
>
> drivers/watchdog/Kconfig | 9 +++
> drivers/watchdog/Makefile | 1 +
> drivers/watchdog/bcm2835_wdt.c | 135 +++++++++++++++++++++++++++++++++
> 3 files changed, 145 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"
Your patch seems to have whitespace problems. Please make sure to send
it e.g. via git send-email.
More comments below...
> + 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..48535c003f
> --- /dev/null
> +++ b/drivers/watchdog/bcm2835_wdt.c
> @@ -0,0 +1,135 @@
> +// 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).
> + * U-boot users specify the timeout as a number of milliseconds
> + * by using variable CONFIG_WATCHDOG_TIMEOUT_MSECS.
> + * The maximum value should be 15999 ms in our case.
> + * However, u-boot internally converts this config value to seconds,
> + * thus specifying 15999 actually means 15000 ms (0xf0000 ticks).
> + */
> +#define PM_WDOG_MAX_TICKS 0x000f0000
> +#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;
> +};
> +
> +static u64 timeout_ticks = PM_WDOG_MAX_TICKS;
Is this static variable really needed? Why not add this variable (if
needed) into the priv struct above instead?
> +
> +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)
> +{
> + timeout_ticks = MS_TO_WDOG_TICKS(timeout_ms);
Again, there should be no need for this static variable. Please move it
to the priv struct instead.
Thanks,
Stefan
> +
> + if (timeout_ticks > PM_WDOG_MAX_TICKS) {
> + printf("WARNING: bcm2835_wdt cannot handle large timeout
> values.\n");
> + printf(" Setting the max value of 15000 ms instead.\n");
> + printf(" Set CONFIG_WATCHDOG_TIMEOUT_MSECS=15000 at most "
> + "to avoid this warning.\n");
> + timeout_ticks = PM_WDOG_MAX_TICKS;
> + }
> +
> + return bcm2835_wdt_start_ticks(dev, timeout_ticks, flags);
> +}
> +
> +static int bcm2835_wdt_reset(struct udevice *dev)
> +{
> + /* restart the timer with the static variable 'timeout_ticks'
> + * saved from the last bcm2835_wdt_start() call.
> + */
> + return bcm2835_wdt_start_ticks(dev, 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;
> +
> + 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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