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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
commitace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch)
treeb2d64bc10158fdd5497876388cd68142ca374ed3 /drivers/watchdog/stm32_iwdg.c
parentInitial commit. (diff)
downloadlinux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz
linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/watchdog/stm32_iwdg.c')
-rw-r--r--drivers/watchdog/stm32_iwdg.c297
1 files changed, 297 insertions, 0 deletions
diff --git a/drivers/watchdog/stm32_iwdg.c b/drivers/watchdog/stm32_iwdg.c
new file mode 100644
index 0000000000..d9fd50df98
--- /dev/null
+++ b/drivers/watchdog/stm32_iwdg.c
@@ -0,0 +1,297 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Driver for STM32 Independent Watchdog
+ *
+ * Copyright (C) STMicroelectronics 2017
+ * Author: Yannick Fertre <yannick.fertre@st.com> for STMicroelectronics.
+ *
+ * This driver is based on tegra_wdt.c
+ *
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/watchdog.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 */
+#define IWDG_WINR 0x10 /* Windows 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 */
+#define KR_KEY_DWA 0x0000 /* write access disable */
+
+/* IWDG_PR register */
+#define PR_SHIFT 2
+#define PR_MIN BIT(PR_SHIFT)
+
+/* IWDG_RLR register values */
+#define RLR_MIN 0x2 /* min value recommended */
+#define RLR_MAX GENMASK(11, 0) /* max value of reload register */
+
+/* IWDG_SR register bit mask */
+#define SR_PVU BIT(0) /* Watchdog prescaler value update */
+#define SR_RVU BIT(1) /* Watchdog counter reload value update */
+
+/* set timeout to 100000 us */
+#define TIMEOUT_US 100000
+#define SLEEP_US 1000
+
+struct stm32_iwdg_data {
+ bool has_pclk;
+ u32 max_prescaler;
+};
+
+static const struct stm32_iwdg_data stm32_iwdg_data = {
+ .has_pclk = false,
+ .max_prescaler = 256,
+};
+
+static const struct stm32_iwdg_data stm32mp1_iwdg_data = {
+ .has_pclk = true,
+ .max_prescaler = 1024,
+};
+
+struct stm32_iwdg {
+ struct watchdog_device wdd;
+ const struct stm32_iwdg_data *data;
+ void __iomem *regs;
+ struct clk *clk_lsi;
+ struct clk *clk_pclk;
+ unsigned int rate;
+};
+
+static inline u32 reg_read(void __iomem *base, u32 reg)
+{
+ return readl_relaxed(base + reg);
+}
+
+static inline void reg_write(void __iomem *base, u32 reg, u32 val)
+{
+ writel_relaxed(val, base + reg);
+}
+
+static int stm32_iwdg_start(struct watchdog_device *wdd)
+{
+ struct stm32_iwdg *wdt = watchdog_get_drvdata(wdd);
+ u32 tout, presc, iwdg_rlr, iwdg_pr, iwdg_sr;
+ int ret;
+
+ dev_dbg(wdd->parent, "%s\n", __func__);
+
+ tout = clamp_t(unsigned int, wdd->timeout,
+ wdd->min_timeout, wdd->max_hw_heartbeat_ms / 1000);
+
+ presc = DIV_ROUND_UP(tout * wdt->rate, RLR_MAX + 1);
+
+ /* The prescaler is align on power of 2 and start at 2 ^ PR_SHIFT. */
+ presc = roundup_pow_of_two(presc);
+ iwdg_pr = presc <= 1 << PR_SHIFT ? 0 : ilog2(presc) - PR_SHIFT;
+ iwdg_rlr = ((tout * wdt->rate) / presc) - 1;
+
+ /* enable write access */
+ reg_write(wdt->regs, IWDG_KR, KR_KEY_EWA);
+
+ /* set prescaler & reload registers */
+ reg_write(wdt->regs, IWDG_PR, iwdg_pr);
+ reg_write(wdt->regs, IWDG_RLR, iwdg_rlr);
+ reg_write(wdt->regs, IWDG_KR, KR_KEY_ENABLE);
+
+ /* wait for the registers to be updated (max 100ms) */
+ ret = readl_relaxed_poll_timeout(wdt->regs + IWDG_SR, iwdg_sr,
+ !(iwdg_sr & (SR_PVU | SR_RVU)),
+ SLEEP_US, TIMEOUT_US);
+ if (ret) {
+ dev_err(wdd->parent, "Fail to set prescaler, reload regs\n");
+ return ret;
+ }
+
+ /* reload watchdog */
+ reg_write(wdt->regs, IWDG_KR, KR_KEY_RELOAD);
+
+ return 0;
+}
+
+static int stm32_iwdg_ping(struct watchdog_device *wdd)
+{
+ struct stm32_iwdg *wdt = watchdog_get_drvdata(wdd);
+
+ dev_dbg(wdd->parent, "%s\n", __func__);
+
+ /* reload watchdog */
+ reg_write(wdt->regs, IWDG_KR, KR_KEY_RELOAD);
+
+ return 0;
+}
+
+static int stm32_iwdg_set_timeout(struct watchdog_device *wdd,
+ unsigned int timeout)
+{
+ dev_dbg(wdd->parent, "%s timeout: %d sec\n", __func__, timeout);
+
+ wdd->timeout = timeout;
+
+ if (watchdog_active(wdd))
+ return stm32_iwdg_start(wdd);
+
+ return 0;
+}
+
+static void stm32_clk_disable_unprepare(void *data)
+{
+ clk_disable_unprepare(data);
+}
+
+static int stm32_iwdg_clk_init(struct platform_device *pdev,
+ struct stm32_iwdg *wdt)
+{
+ struct device *dev = &pdev->dev;
+ u32 ret;
+
+ wdt->clk_lsi = devm_clk_get(dev, "lsi");
+ if (IS_ERR(wdt->clk_lsi))
+ return dev_err_probe(dev, PTR_ERR(wdt->clk_lsi), "Unable to get lsi clock\n");
+
+ /* optional peripheral clock */
+ if (wdt->data->has_pclk) {
+ wdt->clk_pclk = devm_clk_get(dev, "pclk");
+ if (IS_ERR(wdt->clk_pclk))
+ return dev_err_probe(dev, PTR_ERR(wdt->clk_pclk),
+ "Unable to get pclk clock\n");
+
+ ret = clk_prepare_enable(wdt->clk_pclk);
+ if (ret) {
+ dev_err(dev, "Unable to prepare pclk clock\n");
+ return ret;
+ }
+ ret = devm_add_action_or_reset(dev,
+ stm32_clk_disable_unprepare,
+ wdt->clk_pclk);
+ if (ret)
+ return ret;
+ }
+
+ ret = clk_prepare_enable(wdt->clk_lsi);
+ if (ret) {
+ dev_err(dev, "Unable to prepare lsi clock\n");
+ return ret;
+ }
+ ret = devm_add_action_or_reset(dev, stm32_clk_disable_unprepare,
+ wdt->clk_lsi);
+ if (ret)
+ return ret;
+
+ wdt->rate = clk_get_rate(wdt->clk_lsi);
+
+ return 0;
+}
+
+static const struct watchdog_info stm32_iwdg_info = {
+ .options = WDIOF_SETTIMEOUT |
+ WDIOF_MAGICCLOSE |
+ WDIOF_KEEPALIVEPING,
+ .identity = "STM32 Independent Watchdog",
+};
+
+static const struct watchdog_ops stm32_iwdg_ops = {
+ .owner = THIS_MODULE,
+ .start = stm32_iwdg_start,
+ .ping = stm32_iwdg_ping,
+ .set_timeout = stm32_iwdg_set_timeout,
+};
+
+static const struct of_device_id stm32_iwdg_of_match[] = {
+ { .compatible = "st,stm32-iwdg", .data = &stm32_iwdg_data },
+ { .compatible = "st,stm32mp1-iwdg", .data = &stm32mp1_iwdg_data },
+ { /* end node */ }
+};
+MODULE_DEVICE_TABLE(of, stm32_iwdg_of_match);
+
+static int stm32_iwdg_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct watchdog_device *wdd;
+ struct stm32_iwdg *wdt;
+ int ret;
+
+ wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
+ if (!wdt)
+ return -ENOMEM;
+
+ wdt->data = of_device_get_match_data(&pdev->dev);
+ if (!wdt->data)
+ return -ENODEV;
+
+ /* This is the timer base. */
+ wdt->regs = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(wdt->regs))
+ return PTR_ERR(wdt->regs);
+
+ ret = stm32_iwdg_clk_init(pdev, wdt);
+ if (ret)
+ return ret;
+
+ /* Initialize struct watchdog_device. */
+ wdd = &wdt->wdd;
+ wdd->parent = dev;
+ wdd->info = &stm32_iwdg_info;
+ wdd->ops = &stm32_iwdg_ops;
+ wdd->min_timeout = DIV_ROUND_UP((RLR_MIN + 1) * PR_MIN, wdt->rate);
+ wdd->max_hw_heartbeat_ms = ((RLR_MAX + 1) * wdt->data->max_prescaler *
+ 1000) / wdt->rate;
+
+ watchdog_set_drvdata(wdd, wdt);
+ watchdog_set_nowayout(wdd, WATCHDOG_NOWAYOUT);
+ watchdog_init_timeout(wdd, 0, dev);
+
+ /*
+ * In case of CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED is set
+ * (Means U-Boot/bootloaders leaves the watchdog running)
+ * When we get here we should make a decision to prevent
+ * any side effects before user space daemon will take care of it.
+ * The best option, taking into consideration that there is no
+ * way to read values back from hardware, is to enforce watchdog
+ * being run with deterministic values.
+ */
+ if (IS_ENABLED(CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED)) {
+ ret = stm32_iwdg_start(wdd);
+ if (ret)
+ return ret;
+
+ /* Make sure the watchdog is serviced */
+ set_bit(WDOG_HW_RUNNING, &wdd->status);
+ }
+
+ ret = devm_watchdog_register_device(dev, wdd);
+ if (ret)
+ return ret;
+
+ platform_set_drvdata(pdev, wdt);
+
+ return 0;
+}
+
+static struct platform_driver stm32_iwdg_driver = {
+ .probe = stm32_iwdg_probe,
+ .driver = {
+ .name = "iwdg",
+ .of_match_table = stm32_iwdg_of_match,
+ },
+};
+module_platform_driver(stm32_iwdg_driver);
+
+MODULE_AUTHOR("Yannick Fertre <yannick.fertre@st.com>");
+MODULE_DESCRIPTION("STMicroelectronics STM32 Independent Watchdog Driver");
+MODULE_LICENSE("GPL v2");