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authorEric Long <eric.long@spreadtrum.com>2017-11-06 03:46:28 +0100
committerWim Van Sebroeck <wim@iguana.be>2017-12-28 20:45:40 +0100
commit477603467009673d0965ca7ec165a09bd0fcb87e (patch)
treed2ac478f2edce54d20e9bd378596693f9c96f058 /drivers/watchdog/sprd_wdt.c
parentdt-bindings: watchdog: Add Spreadtrum watchdog documentation (diff)
downloadlinux-477603467009673d0965ca7ec165a09bd0fcb87e.tar.xz
linux-477603467009673d0965ca7ec165a09bd0fcb87e.zip
watchdog: Add Spreadtrum watchdog driver
This patch adds the watchdog driver for Spreadtrum SC9860 platform. Signed-off-by: Eric Long <eric.long@spreadtrum.com> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Diffstat (limited to 'drivers/watchdog/sprd_wdt.c')
-rw-r--r--drivers/watchdog/sprd_wdt.c399
1 files changed, 399 insertions, 0 deletions
diff --git a/drivers/watchdog/sprd_wdt.c b/drivers/watchdog/sprd_wdt.c
new file mode 100644
index 000000000000..a8b280ff33e0
--- /dev/null
+++ b/drivers/watchdog/sprd_wdt.c
@@ -0,0 +1,399 @@
+/*
+ * Spreadtrum watchdog driver
+ * Copyright (C) 2017 Spreadtrum - http://www.spreadtrum.com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ */
+
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/watchdog.h>
+
+#define SPRD_WDT_LOAD_LOW 0x0
+#define SPRD_WDT_LOAD_HIGH 0x4
+#define SPRD_WDT_CTRL 0x8
+#define SPRD_WDT_INT_CLR 0xc
+#define SPRD_WDT_INT_RAW 0x10
+#define SPRD_WDT_INT_MSK 0x14
+#define SPRD_WDT_CNT_LOW 0x18
+#define SPRD_WDT_CNT_HIGH 0x1c
+#define SPRD_WDT_LOCK 0x20
+#define SPRD_WDT_IRQ_LOAD_LOW 0x2c
+#define SPRD_WDT_IRQ_LOAD_HIGH 0x30
+
+/* WDT_CTRL */
+#define SPRD_WDT_INT_EN_BIT BIT(0)
+#define SPRD_WDT_CNT_EN_BIT BIT(1)
+#define SPRD_WDT_NEW_VER_EN BIT(2)
+#define SPRD_WDT_RST_EN_BIT BIT(3)
+
+/* WDT_INT_CLR */
+#define SPRD_WDT_INT_CLEAR_BIT BIT(0)
+#define SPRD_WDT_RST_CLEAR_BIT BIT(3)
+
+/* WDT_INT_RAW */
+#define SPRD_WDT_INT_RAW_BIT BIT(0)
+#define SPRD_WDT_RST_RAW_BIT BIT(3)
+#define SPRD_WDT_LD_BUSY_BIT BIT(4)
+
+/* 1s equal to 32768 counter steps */
+#define SPRD_WDT_CNT_STEP 32768
+
+#define SPRD_WDT_UNLOCK_KEY 0xe551
+#define SPRD_WDT_MIN_TIMEOUT 3
+#define SPRD_WDT_MAX_TIMEOUT 60
+
+#define SPRD_WDT_CNT_HIGH_SHIFT 16
+#define SPRD_WDT_LOW_VALUE_MASK GENMASK(15, 0)
+#define SPRD_WDT_LOAD_TIMEOUT 1000
+
+struct sprd_wdt {
+ void __iomem *base;
+ struct watchdog_device wdd;
+ struct clk *enable;
+ struct clk *rtc_enable;
+ int irq;
+};
+
+static inline struct sprd_wdt *to_sprd_wdt(struct watchdog_device *wdd)
+{
+ return container_of(wdd, struct sprd_wdt, wdd);
+}
+
+static inline void sprd_wdt_lock(void __iomem *addr)
+{
+ writel_relaxed(0x0, addr + SPRD_WDT_LOCK);
+}
+
+static inline void sprd_wdt_unlock(void __iomem *addr)
+{
+ writel_relaxed(SPRD_WDT_UNLOCK_KEY, addr + SPRD_WDT_LOCK);
+}
+
+static irqreturn_t sprd_wdt_isr(int irq, void *dev_id)
+{
+ struct sprd_wdt *wdt = (struct sprd_wdt *)dev_id;
+
+ sprd_wdt_unlock(wdt->base);
+ writel_relaxed(SPRD_WDT_INT_CLEAR_BIT, wdt->base + SPRD_WDT_INT_CLR);
+ sprd_wdt_lock(wdt->base);
+ watchdog_notify_pretimeout(&wdt->wdd);
+ return IRQ_HANDLED;
+}
+
+static u32 sprd_wdt_get_cnt_value(struct sprd_wdt *wdt)
+{
+ u32 val;
+
+ val = readl_relaxed(wdt->base + SPRD_WDT_CNT_HIGH) <<
+ SPRD_WDT_CNT_HIGH_SHIFT;
+ val |= readl_relaxed(wdt->base + SPRD_WDT_CNT_LOW) &
+ SPRD_WDT_LOW_VALUE_MASK;
+
+ return val;
+}
+
+static int sprd_wdt_load_value(struct sprd_wdt *wdt, u32 timeout,
+ u32 pretimeout)
+{
+ u32 val, delay_cnt = 0;
+ u32 tmr_step = timeout * SPRD_WDT_CNT_STEP;
+ u32 prtmr_step = pretimeout * SPRD_WDT_CNT_STEP;
+
+ sprd_wdt_unlock(wdt->base);
+ writel_relaxed((tmr_step >> SPRD_WDT_CNT_HIGH_SHIFT) &
+ SPRD_WDT_LOW_VALUE_MASK, wdt->base + SPRD_WDT_LOAD_HIGH);
+ writel_relaxed((tmr_step & SPRD_WDT_LOW_VALUE_MASK),
+ wdt->base + SPRD_WDT_LOAD_LOW);
+ writel_relaxed((prtmr_step >> SPRD_WDT_CNT_HIGH_SHIFT) &
+ SPRD_WDT_LOW_VALUE_MASK,
+ wdt->base + SPRD_WDT_IRQ_LOAD_HIGH);
+ writel_relaxed(prtmr_step & SPRD_WDT_LOW_VALUE_MASK,
+ wdt->base + SPRD_WDT_IRQ_LOAD_LOW);
+ sprd_wdt_lock(wdt->base);
+
+ /*
+ * Waiting the load value operation done,
+ * it needs two or three RTC clock cycles.
+ */
+ do {
+ val = readl_relaxed(wdt->base + SPRD_WDT_INT_RAW);
+ if (!(val & SPRD_WDT_LD_BUSY_BIT))
+ break;
+
+ cpu_relax();
+ } while (delay_cnt++ < SPRD_WDT_LOAD_TIMEOUT);
+
+ if (delay_cnt >= SPRD_WDT_LOAD_TIMEOUT)
+ return -EBUSY;
+ return 0;
+}
+
+static int sprd_wdt_enable(struct sprd_wdt *wdt)
+{
+ u32 val;
+ int ret;
+
+ ret = clk_prepare_enable(wdt->enable);
+ if (ret)
+ return ret;
+ ret = clk_prepare_enable(wdt->rtc_enable);
+ if (ret)
+ return ret;
+
+ sprd_wdt_unlock(wdt->base);
+ val = readl_relaxed(wdt->base + SPRD_WDT_CTRL);
+ val |= SPRD_WDT_NEW_VER_EN;
+ writel_relaxed(val, wdt->base + SPRD_WDT_CTRL);
+ sprd_wdt_lock(wdt->base);
+ return 0;
+}
+
+static void sprd_wdt_disable(void *_data)
+{
+ struct sprd_wdt *wdt = _data;
+
+ sprd_wdt_unlock(wdt->base);
+ writel_relaxed(0x0, wdt->base + SPRD_WDT_CTRL);
+ sprd_wdt_lock(wdt->base);
+
+ clk_disable_unprepare(wdt->rtc_enable);
+ clk_disable_unprepare(wdt->enable);
+}
+
+static int sprd_wdt_start(struct watchdog_device *wdd)
+{
+ struct sprd_wdt *wdt = to_sprd_wdt(wdd);
+ u32 val;
+ int ret;
+
+ ret = sprd_wdt_load_value(wdt, wdd->timeout, wdd->pretimeout);
+ if (ret)
+ return ret;
+
+ sprd_wdt_unlock(wdt->base);
+ val = readl_relaxed(wdt->base + SPRD_WDT_CTRL);
+ val |= SPRD_WDT_CNT_EN_BIT | SPRD_WDT_INT_EN_BIT | SPRD_WDT_RST_EN_BIT;
+ writel_relaxed(val, wdt->base + SPRD_WDT_CTRL);
+ sprd_wdt_lock(wdt->base);
+ set_bit(WDOG_HW_RUNNING, &wdd->status);
+
+ return 0;
+}
+
+static int sprd_wdt_stop(struct watchdog_device *wdd)
+{
+ struct sprd_wdt *wdt = to_sprd_wdt(wdd);
+ u32 val;
+
+ sprd_wdt_unlock(wdt->base);
+ val = readl_relaxed(wdt->base + SPRD_WDT_CTRL);
+ val &= ~(SPRD_WDT_CNT_EN_BIT | SPRD_WDT_RST_EN_BIT |
+ SPRD_WDT_INT_EN_BIT);
+ writel_relaxed(val, wdt->base + SPRD_WDT_CTRL);
+ sprd_wdt_lock(wdt->base);
+ return 0;
+}
+
+static int sprd_wdt_set_timeout(struct watchdog_device *wdd,
+ u32 timeout)
+{
+ struct sprd_wdt *wdt = to_sprd_wdt(wdd);
+
+ if (timeout == wdd->timeout)
+ return 0;
+
+ wdd->timeout = timeout;
+
+ return sprd_wdt_load_value(wdt, timeout, wdd->pretimeout);
+}
+
+static int sprd_wdt_set_pretimeout(struct watchdog_device *wdd,
+ u32 new_pretimeout)
+{
+ struct sprd_wdt *wdt = to_sprd_wdt(wdd);
+
+ if (new_pretimeout < wdd->min_timeout)
+ return -EINVAL;
+
+ wdd->pretimeout = new_pretimeout;
+
+ return sprd_wdt_load_value(wdt, wdd->timeout, new_pretimeout);
+}
+
+static u32 sprd_wdt_get_timeleft(struct watchdog_device *wdd)
+{
+ struct sprd_wdt *wdt = to_sprd_wdt(wdd);
+ u32 val;
+
+ val = sprd_wdt_get_cnt_value(wdt);
+ val = val / SPRD_WDT_CNT_STEP;
+
+ return val;
+}
+
+static const struct watchdog_ops sprd_wdt_ops = {
+ .owner = THIS_MODULE,
+ .start = sprd_wdt_start,
+ .stop = sprd_wdt_stop,
+ .set_timeout = sprd_wdt_set_timeout,
+ .set_pretimeout = sprd_wdt_set_pretimeout,
+ .get_timeleft = sprd_wdt_get_timeleft,
+};
+
+static const struct watchdog_info sprd_wdt_info = {
+ .options = WDIOF_SETTIMEOUT |
+ WDIOF_PRETIMEOUT |
+ WDIOF_MAGICCLOSE |
+ WDIOF_KEEPALIVEPING,
+ .identity = "Spreadtrum Watchdog Timer",
+};
+
+static int sprd_wdt_probe(struct platform_device *pdev)
+{
+ struct resource *wdt_res;
+ struct sprd_wdt *wdt;
+ int ret;
+
+ wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
+ if (!wdt)
+ return -ENOMEM;
+
+ wdt_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ wdt->base = devm_ioremap_resource(&pdev->dev, wdt_res);
+ if (IS_ERR(wdt->base)) {
+ dev_err(&pdev->dev, "failed to map memory resource\n");
+ return PTR_ERR(wdt->base);
+ }
+
+ wdt->enable = devm_clk_get(&pdev->dev, "enable");
+ if (IS_ERR(wdt->enable)) {
+ dev_err(&pdev->dev, "can't get the enable clock\n");
+ return PTR_ERR(wdt->enable);
+ }
+
+ wdt->rtc_enable = devm_clk_get(&pdev->dev, "rtc_enable");
+ if (IS_ERR(wdt->rtc_enable)) {
+ dev_err(&pdev->dev, "can't get the rtc enable clock\n");
+ return PTR_ERR(wdt->rtc_enable);
+ }
+
+ wdt->irq = platform_get_irq(pdev, 0);
+ if (wdt->irq < 0) {
+ dev_err(&pdev->dev, "failed to get IRQ resource\n");
+ return wdt->irq;
+ }
+
+ ret = devm_request_irq(&pdev->dev, wdt->irq, sprd_wdt_isr,
+ IRQF_NO_SUSPEND, "sprd-wdt", (void *)wdt);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to register irq\n");
+ return ret;
+ }
+
+ wdt->wdd.info = &sprd_wdt_info;
+ wdt->wdd.ops = &sprd_wdt_ops;
+ wdt->wdd.parent = &pdev->dev;
+ wdt->wdd.min_timeout = SPRD_WDT_MIN_TIMEOUT;
+ wdt->wdd.max_timeout = SPRD_WDT_MAX_TIMEOUT;
+ wdt->wdd.timeout = SPRD_WDT_MAX_TIMEOUT;
+
+ ret = sprd_wdt_enable(wdt);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to enable wdt\n");
+ return ret;
+ }
+ ret = devm_add_action(&pdev->dev, sprd_wdt_disable, wdt);
+ if (ret) {
+ sprd_wdt_disable(wdt);
+ dev_err(&pdev->dev, "Failed to add wdt disable action\n");
+ return ret;
+ }
+
+ watchdog_set_nowayout(&wdt->wdd, WATCHDOG_NOWAYOUT);
+ watchdog_init_timeout(&wdt->wdd, 0, &pdev->dev);
+
+ ret = devm_watchdog_register_device(&pdev->dev, &wdt->wdd);
+ if (ret) {
+ sprd_wdt_disable(wdt);
+ dev_err(&pdev->dev, "failed to register watchdog\n");
+ return ret;
+ }
+ platform_set_drvdata(pdev, wdt);
+
+ return 0;
+}
+
+static int __maybe_unused sprd_wdt_pm_suspend(struct device *dev)
+{
+ struct watchdog_device *wdd = dev_get_drvdata(dev);
+ struct sprd_wdt *wdt = dev_get_drvdata(dev);
+
+ if (watchdog_active(wdd))
+ sprd_wdt_stop(&wdt->wdd);
+ sprd_wdt_disable(wdt);
+
+ return 0;
+}
+
+static int __maybe_unused sprd_wdt_pm_resume(struct device *dev)
+{
+ struct watchdog_device *wdd = dev_get_drvdata(dev);
+ struct sprd_wdt *wdt = dev_get_drvdata(dev);
+ int ret;
+
+ ret = sprd_wdt_enable(wdt);
+ if (ret)
+ return ret;
+
+ if (watchdog_active(wdd)) {
+ ret = sprd_wdt_start(&wdt->wdd);
+ if (ret) {
+ sprd_wdt_disable(wdt);
+ return ret;
+ }
+ }
+
+ return 0;
+}
+
+static const struct dev_pm_ops sprd_wdt_pm_ops = {
+ SET_SYSTEM_SLEEP_PM_OPS(sprd_wdt_pm_suspend,
+ sprd_wdt_pm_resume)
+};
+
+static const struct of_device_id sprd_wdt_match_table[] = {
+ { .compatible = "sprd,sp9860-wdt", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, sprd_wdt_match_table);
+
+static struct platform_driver sprd_watchdog_driver = {
+ .probe = sprd_wdt_probe,
+ .driver = {
+ .name = "sprd-wdt",
+ .of_match_table = sprd_wdt_match_table,
+ .pm = &sprd_wdt_pm_ops,
+ },
+};
+module_platform_driver(sprd_watchdog_driver);
+
+MODULE_AUTHOR("Eric Long <eric.long@spreadtrum.com>");
+MODULE_DESCRIPTION("Spreadtrum Watchdog Timer Controller Driver");
+MODULE_LICENSE("GPL v2");