This patch adds IWDG (Independent WatchDoG) support for
STM32MP platform.
Signed-off-by: Christophe Kerello <christophe.kere...@st.com>
Signed-off-by: Patrice Chotard <patrice.chot...@st.com>
---
Changes in v2:
- Rename timeout variable in timeout_ms in stm32mp_wdt_start()
MAINTAINERS | 1 +
arch/arm/mach-stm32mp/Kconfig | 1 +
drivers/watchdog/Kconfig | 8 +++
drivers/watchdog/Makefile | 1 +
drivers/watchdog/stm32mp_wdt.c | 135 +++++++++++++++++++++++++++++++++++++++++
5 files changed, 146 insertions(+)
create mode 100644 drivers/watchdog/stm32mp_wdt.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 09f31cd..eec2603 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -311,6 +311,7 @@ F: drivers/ram/stm32mp1/
F: drivers/misc/stm32_rcc.c
F: drivers/reset/stm32-reset.c
F: drivers/spi/stm32_qspi.c
+F: drivers/watchdog/stm32mp_wdt.c
ARM STM STV0991
M: Vikas Manocha <vikas.mano...@st.com>
diff --git a/arch/arm/mach-stm32mp/Kconfig b/arch/arm/mach-stm32mp/Kconfig
index 73aa382..4e7cc2e 100644
--- a/arch/arm/mach-stm32mp/Kconfig
+++ b/arch/arm/mach-stm32mp/Kconfig
@@ -17,6 +17,7 @@ config SPL
select SPL_DM_RESET
select SPL_SERIAL_SUPPORT
select SPL_SYSCON
+ select SPL_WATCHDOG_SUPPORT
imply SPL_DISPLAY_PRINT
imply SPL_LIBDISK_SUPPORT
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 4a3ff7a..d582abe 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -147,6 +147,14 @@ config WDT_SANDBOX
can be probed and supports all of the methods of WDT, but does not
really do anything.
+config WDT_STM32MP
+ bool "IWDG watchdog driver for STM32 MP's family"
+ depends on WDT
+ imply WATCHDOG
+ help
+ Enable the STM32 watchdog (IWDG) driver. Enable support to
+ configure STM32's on-SoC watchdog.
+
config XILINX_TB_WATCHDOG
bool "Xilinx Axi watchdog timer support"
depends on WDT
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 40b2f4b..a3ebff8 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -27,3 +27,4 @@ obj-$(CONFIG_WDT_CDNS) += cdns_wdt.o
obj-$(CONFIG_WDT_MPC8xx) += mpc8xx_wdt.o
obj-$(CONFIG_WDT_MT7621) += mt7621_wdt.o
obj-$(CONFIG_WDT_MTK) += mtk_wdt.o
+obj-$(CONFIG_WDT_STM32MP) += stm32mp_wdt.o
diff --git a/drivers/watchdog/stm32mp_wdt.c b/drivers/watchdog/stm32mp_wdt.c
new file mode 100644
index 0000000..8093d0a
--- /dev/null
+++ b/drivers/watchdog/stm32mp_wdt.c
@@ -0,0 +1,135 @@
+// SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause
+/*
+ * Copyright (C) 2019, STMicroelectronics - All Rights Reserved
+ */
+
+#include <common.h>
+#include <clk.h>
+#include <dm.h>
+#include <syscon.h>
+#include <wdt.h>
+#include <asm/io.h>
+#include <linux/iopoll.h>
+
+/* IWDG registers */
+#define IWDG_KR 0x00 /* Key register */
+#define IWDG_PR 0x04 /* Prescaler Register */
+#define IWDG_RLR 0x08 /* ReLoad Register */
+#define IWDG_SR 0x0C /* Status Register */
+
+/* IWDG_KR register bit mask */
+#define KR_KEY_RELOAD 0xAAAA /* Reload counter enable */
+#define KR_KEY_ENABLE 0xCCCC /* Peripheral enable */
+#define KR_KEY_EWA 0x5555 /* Write access enable */
+
+/* IWDG_PR register bit values */
+#define PR_256 0x06 /* Prescaler set to 256 */
+
+/* IWDG_RLR register values */
+#define RLR_MAX 0xFFF /* Max value supported by reload
register */
+
+/* IWDG_SR register bit values */
+#define SR_PVU BIT(0) /* Watchdog prescaler value update */
+#define SR_RVU BIT(1) /* Watchdog counter reload value update */
+
+struct stm32mp_wdt_priv {
+ fdt_addr_t base; /* registers addr in physical memory */
+ unsigned long wdt_clk_rate; /* Watchdog dedicated clock rate */
+};
+
+static int stm32mp_wdt_reset(struct udevice *dev)
+{
+ struct stm32mp_wdt_priv *priv = dev_get_priv(dev);
+
+ writel(KR_KEY_RELOAD, priv->base + IWDG_KR);
+
+ return 0;
+}
+
+static int stm32mp_wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags)
+{
+ struct stm32mp_wdt_priv *priv = dev_get_priv(dev);
+ int reload;
+ u32 val;
+ int ret;
+
+ /* Prescaler fixed to 256 */
+ reload = timeout_ms * priv->wdt_clk_rate / 256;
+ if (reload > RLR_MAX + 1)
+ /* Force to max watchdog counter reload value */
+ reload = RLR_MAX + 1;
+ else if (!reload)
+ /* Force to min watchdog counter reload value */
+ reload = priv->wdt_clk_rate / 256;
+
+ /* Set prescaler & reload registers */
+ writel(KR_KEY_EWA, priv->base + IWDG_KR);
+ writel(PR_256, priv->base + IWDG_PR);
+ writel(reload - 1, priv->base + IWDG_RLR);
+
+ /* Enable watchdog */
+ writel(KR_KEY_ENABLE, priv->base + IWDG_KR);
+
+ /* Wait for the registers to be updated */
+ ret = readl_poll_timeout(priv->base + IWDG_SR, val,
+ val & (SR_PVU | SR_RVU), CONFIG_SYS_HZ);
+
+ if (ret < 0) {
+ pr_err("Updating IWDG registers timeout");
+ return -ETIMEDOUT;
+ }
+
+ return 0;
+}
+
+static int stm32mp_wdt_probe(struct udevice *dev)
+{
+ struct stm32mp_wdt_priv *priv = dev_get_priv(dev);
+ struct clk clk;
+ int ret;
+
+ debug("IWDG init\n");
+
+ priv->base = devfdt_get_addr(dev);
+ if (priv->base == FDT_ADDR_T_NONE)
+ return -EINVAL;
+
+ /* Enable clock */
+ ret = clk_get_by_name(dev, "pclk", &clk);
+ if (ret)
+ return ret;
+
+ ret = clk_enable(&clk);
+ if (ret)
+ return ret;
+
+ /* Get LSI clock */
+ ret = clk_get_by_name(dev, "lsi", &clk);
+ if (ret)
+ return ret;
+
+ priv->wdt_clk_rate = clk_get_rate(&clk);
+
+ debug("IWDG init done\n");
+
+ return 0;
+}
+
+static const struct wdt_ops stm32mp_wdt_ops = {
+ .start = stm32mp_wdt_start,
+ .reset = stm32mp_wdt_reset,
+};
+
+static const struct udevice_id stm32mp_wdt_match[] = {
+ { .compatible = "st,stm32mp1-iwdg" },
+ { /* sentinel */ }
+};
+
+U_BOOT_DRIVER(stm32mp_wdt) = {
+ .name = "stm32mp-wdt",
+ .id = UCLASS_WDT,
+ .of_match = stm32mp_wdt_match,
+ .priv_auto_alloc_size = sizeof(struct stm32mp_wdt_priv),
+ .probe = stm32mp_wdt_probe,
+ .ops = &stm32mp_wdt_ops,
+};
--
1.9.1
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