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(+) 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>
