On Wed, Apr 23, 2025 at 02:19:39AM +0000, Paul Sajna wrote:
> From: Casey Connolly <casey.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 keep the watchdog happy and prevent this
> annoying behaviour.
>
> Signed-off-by: Casey Connolly <casey.conno...@linaro.org>
> Signed-off-by: Paul Sajna <he...@paulsajna.com>
> Co-authored-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 Casey 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 Casey'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 :)
> ---
> Changes in v3:
> - Squash commit 1 and 2
> - remove duplicated line of code
> - Link to v2:
> https://lore.kernel.org/r/20250421-b4-qcom-wdt-v2-0-b2250efa0...@paulsajna.com
>
> Changes in v2:
> - Add watchdog start
> - Add watchdog reset
> - Remove stop from the probe function
> - Use dev_err instead of printf
> - Update Casey's name
> - Add myself as an author
> -
> - Link to v1:
> https://lore.kernel.org/r/20250413-b4-qcom-wdt-v1-1-db42cb93d...@paulsajna.com
> ---
> configs/qcom_defconfig | 2 +
> drivers/watchdog/Kconfig | 7 +++
> drivers/watchdog/Makefile | 1 +
> drivers/watchdog/qcom-wdt.c | 117
> ++++++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 127 insertions(+)
>
Looks reasonable to me, FWIW:
Acked-by: Sumit Garg <sumit.g...@oss.qualcomm.com>
-Sumit
> 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..3601ba93774730f78574b2fd74b8c513e7ce22e1
> --- /dev/null
> +++ b/drivers/watchdog/qcom-wdt.c
> @@ -0,0 +1,117 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (c) 2014, The Linux Foundation. All rights reserved.
> + * Copyright (c) Linaro Ltd. 2024
> + *
> + * Authors:
> + * Casey Connolly <casey.conno...@linaro.org>
> + * Paul Sajna <he...@paulsajna.com>
> + *
> + * Derived from linux/drivers/watchdog/qcom-wdt.c
> + */
> +
> +#include <dm.h>
> +#include <dm/device_compat.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)
> +{
> + struct qcom_wdt *wdt = dev_get_priv(dev);
> +
> + writel(0, wdt_addr(wdt, WDT_EN));
> + writel(1, wdt_addr(wdt, WDT_RST));
> + writel(1, wdt_addr(wdt, WDT_EN));
> + if (readl(wdt_addr(wdt, WDT_EN)) != 1) {
> + dev_err(dev, "Failed to enable Qualcomm watchdog!\n");
> + return -EIO;
> + }
> + 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))) {
> + dev_err(dev, "Failed to disable Qualcomm watchdog!\n");
> + return -EIO;
> + }
> +
> + return 0;
> +}
> +
> +int qcom_wdt_reset(struct udevice *dev)
> +{
> + struct qcom_wdt *wdt = dev_get_priv(dev);
> +
> + writel(1, wdt_addr(wdt, WDT_RST));
> + 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);
> +
> + wdt->base = dev_read_addr_ptr(dev);
> + wdt->layout = data->offset;
> +
> + return 0;
> +}
> +
> +static const struct wdt_ops qcom_wdt_ops = {
> + .start = qcom_wdt_start,
> + .stop = qcom_wdt_stop,
> + .reset = qcom_wdt_reset,
> +};
> +
> +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: 0eebdd17888005751cd77cf3794c5292d36f481a
> change-id: 20250413-b4-qcom-wdt-e7b913fc375e
>
> Best regards,
> --
> Paul Sajna <he...@paulsajna.com>
>
>
