Re: [U-Boot] [PATCH 3/4] watchdog: stm32mp: Add watchdog driver

On 29.04.19 11:23, Patrice Chotard wrote:

This patch adds IWDG (Independent WatchDoG) support for STM32MP platform.

Signed-off-by: Christophe Kerello christophe.kerello@st.com Signed-off-by: Patrice Chotard patrice.chotard@st.com

---

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.manocha@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..82db2c6 --- /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, ulong flags)

s/timeout/timeout_ms (see below).

+{

• struct stm32mp_wdt_priv *priv = dev_get_priv(dev);
• int reload;
• u32 val;
• int ret;
• /* Prescaler fixed to 256 */
• reload = timeout * priv->wdt_clk_rate / 256;

Just checking, if this takes into account that timeout is passed in ms (milli-seconds) to the DM wdt_start() function. That's why I prefer to see timeout explicitly named to "timeout_ms" instead.

Thanks, Stefan

• 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,

+};

Viele Grüße, Stefan