Thanks for the feedback, I'll try to circle back to it in a few days, perhaps
on the weekend.
-------- Original Message --------
On 4/14/25 12:24 AM, Neil Armstrong <neil.armstr...@linaro.org> wrote:
> Hi,
>
> On 13/04/2025 12:12, Paul Sajna wrote:
> > From: Caleb Connolly <caleb.conno...@linaro.org>
> >
> > Some Qualcomm device vendors decide to turn the watchdog on in the
> > bootloader, resulting in the device being reset if it isn't petted every
> > ~30 seconds. Introduce a driver to disable the watchdog and prevent this
> > annoying behaviour.
> >
> > Signed-off-by: Caleb Connolly <caleb.conno...@linaro.org>
> > Signed-off-by: Paul Sajna <he...@paulsajna.com>
> > Tested-by: Paul Sajna <he...@paulsajna.com>
> > ---
> > This patch introduces a simple watchdog driver for Qualcomm devices.
> >
> > Some devices, including one I have been spending a lot of time with,
> > the LG G7 ThinQ (codename judyln, arch sdm845) will reset within 30
> > seconds if the watchdog is not serviced.
> >
> > I have tested this patch from Caleb Connolly that is over a year old and
> has
> > not yet been upstreamed, and it is very useful to me. I can hardly use
> > u-boot on this device without it. I have received Caleb's permission to
> > work on upstreaming this patch.
> >
> > This is my first contribution to U-Boot, and I am unfamiliar with
> > mailing list workflows, so please be patient :)
> > ---
> > configs/qcom_defconfig | 2 +
> > drivers/watchdog/Kconfig | 7 ++++
> > drivers/watchdog/Makefile | 1 +
> > drivers/watchdog/qcom-wdt.c | 100
> ++++++++++++++++++++++++++++++++++++++++++++
> > 4 files changed, 110 insertions(+)
> >
> > diff --git a/configs/qcom_defconfig b/configs/qcom_defconfig
> > index
> 537806450dc4a61d3c617cdd2b0cfb8eab1c343c..0232f6d51c552bd06c8ba72b71edb5cb72fe0706
> 100644
> > --- a/configs/qcom_defconfig
> > +++ b/configs/qcom_defconfig
> > @@ -144,3 +144,5 @@ CONFIG_VIDEO_FONT_16X32=y
> > CONFIG_SYS_WHITE_ON_BLACK=y
> > CONFIG_NO_FB_CLEAR=y
> > CONFIG_VIDEO_SIMPLE=y
> > +CONFIG_WDT_QCOM=y
> > +CONFIG_WDT=y
> > diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> > index
> 1bb67f5035231df9f6ce01adb08d074855393143..808f4e578e28e7812f93b393a7f7d95d9501cdd4
> 100644
> > --- a/drivers/watchdog/Kconfig
> > +++ b/drivers/watchdog/Kconfig
> > @@ -335,6 +335,13 @@ config WDT_K3_RTI_FW_FILE
> >
> > endif
> >
> > +config WDT_QCOM
> > + bool "Qualcomm watchdog timer support"
> > + depends on WDT && ARCH_SNAPDRAGON
> > + help
> > + Select this to enable Qualcomm watchdog timer, which can be found on
> > + some Qualcomm chips.
> > +
> > config WDT_SANDBOX
> > bool "Enable Watchdog Timer support for Sandbox"
> > depends on SANDBOX && WDT
> > diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> > index
> e6bd4c587af6133c405dde6dbada8050debc781c..5eaabd4aba58c815de4165f901aecfba0e0da255
> 100644
> > --- a/drivers/watchdog/Makefile
> > +++ b/drivers/watchdog/Makefile
> > @@ -54,3 +54,4 @@ obj-$(CONFIG_WDT_SUNXI) += sunxi_wdt.o
> > obj-$(CONFIG_WDT_TANGIER) += tangier_wdt.o
> > obj-$(CONFIG_WDT_XILINX) += xilinx_wwdt.o
> > obj-$(CONFIG_WDT_ADI) += adi_wdt.o
> > +obj-$(CONFIG_WDT_QCOM) += qcom-wdt.o
> > diff --git a/drivers/watchdog/qcom-wdt.c b/drivers/watchdog/qcom-wdt.c
> > new file mode 100644
> > index
> 0000000000000000000000000000000000000000..a7ce31ef811c717fd16700aa7d984a000763a93e
> > --- /dev/null
> > +++ b/drivers/watchdog/qcom-wdt.c
> > @@ -0,0 +1,100 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * Copyright (c) 2014, The Linux Foundation. All rights reserved.
> > + * Copyright (c) Linaro Ltd. 2024
> > + *
> > + * Authors:
> > + * Caleb Connolly <caleb.conno...@linaro.org>
> > + *
> > + * Derived from linux/drivers/watchdog/qcom-wdt.c
> > + */
> > +
> > +#include <dm.h>
> > +#include <wdt.h>
> > +
> > +#include <asm/io.h>
> > +
> > +enum wdt_reg {
> > + WDT_RST,
> > + WDT_EN,
> > + WDT_STS,
> > + WDT_BARK_TIME,
> > + WDT_BITE_TIME,
> > +};
> > +
> > +struct qcom_wdt_match_data {
> > + const u32 *offset;
> > +};
> > +
> > +struct qcom_wdt {
> > + void __iomem *base;
> > + const u32 *layout;
> > +};
> > +
> > +static const u32 reg_offset_data_kpss[] = {
> > + [WDT_RST] = 0x4,
> > + [WDT_EN] = 0x8,
> > + [WDT_STS] = 0xC,
> > + [WDT_BARK_TIME] = 0x10,
> > + [WDT_BITE_TIME] = 0x14,
> > +};
> > +
> > +static const struct qcom_wdt_match_data match_data_kpss = {
> > + .offset = reg_offset_data_kpss,
> > +};
> > +
> > +static void __iomem *wdt_addr(struct qcom_wdt *wdt, enum wdt_reg reg)
> > +{
> > + return wdt->base + wdt->layout[reg];
> > +}
> > +
> > +int qcom_wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags)
> > +{
> > + /* unimplemented */
> > + return 0;
> > +}
> > +
> > +int qcom_wdt_stop(struct udevice *dev)
> > +{
> > + struct qcom_wdt *wdt = dev_get_priv(dev);
> > +
> > + writel(0, wdt_addr(wdt, WDT_EN));
> > + if (readl(wdt_addr(wdt, WDT_EN))) {
> > + printf("Failed to disable Qualcomm watchdog!\n");
> > + return -EIO;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static int qcom_wdt_probe(struct udevice *dev)
> > +{
> > + struct qcom_wdt *wdt = dev_get_priv(dev);
> > + struct qcom_wdt_match_data *data = (void *)dev_get_driver_data(dev);
> > + int ret;
> > +
> > + wdt->base = dev_read_addr_ptr(dev);
> > + wdt->layout = data->offset;
> > +
> > + ret = qcom_wdt_stop(dev);
>
> Fine but perhaps just add a simple code into qcom_wdt_start() and add
> a reset callback to allow people to actually use the wdog from u-boot
> with CONFIG_WATCHDOG_AUTOSTART and/or u-boot,autostart.
>
> No need to implement set_timeout, we can use the bootloader value.
>
> > +
> > + return ret;
> > +}
> > +
> > +static const struct wdt_ops qcom_wdt_ops = {
> > + .stop = qcom_wdt_stop,
>
> You forgot qcom_wdt_start()
>
> > +};
> > +
> > +static const struct udevice_id qcom_wdt_ids[] = {
> > + { .compatible = "qcom,kpss-wdt", .data = (ulong)&match_data_kpss },
> > + {}
> > +};
> > +
> > +U_BOOT_DRIVER(qcom_wdt) = {
> > + .name = "qcom_wdt",
> > + .id = UCLASS_WDT,
> > + .of_match = qcom_wdt_ids,
> > + .ops = &qcom_wdt_ops,
> > + .probe = qcom_wdt_probe,
> > + .priv_auto = sizeof(struct qcom_wdt),
> > +};
> >
> > ---
> > base-commit: f3563fc30356c8079527b90e532407050dff7c7b
> > change-id: 20250413-b4-qcom-wdt-e7b913fc375e
> >
> > Best regards,
>
>
>
