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>
