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Subject[PATCH 2/2] watchdog: Add Spreadtrum watchdog driver
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This patch adds the watchdog driver for Spreadtrum SC9860 platform.

Signed-off-by: Eric Long <eric.long@spreadtrum.com>
---
drivers/watchdog/Kconfig | 8 +
drivers/watchdog/Makefile | 1 +
drivers/watchdog/sprd_wdt.c | 366 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 375 insertions(+)
create mode 100644 drivers/watchdog/sprd_wdt.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index c722cbf..ea07718 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -787,6 +787,14 @@ config UNIPHIER_WATCHDOG
To compile this driver as a module, choose M here: the
module will be called uniphier_wdt.

+config SPRD_WATCHDOG
+ tristate "Spreadtrum watchdog support"
+ depends on ARCH_SPRD
+ select WATCHDOG_CORE
+ help
+ Say Y here to include support watchdog timer embedded
+ into the Spreadtrum system.
+
# AVR32 Architecture

config AT32AP700X_WDT
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 56adf9f..187cca2 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -87,6 +87,7 @@ obj-$(CONFIG_ASPEED_WATCHDOG) += aspeed_wdt.o
obj-$(CONFIG_ZX2967_WATCHDOG) += zx2967_wdt.o
obj-$(CONFIG_STM32_WATCHDOG) += stm32_iwdg.o
obj-$(CONFIG_UNIPHIER_WATCHDOG) += uniphier_wdt.o
+obj-$(CONFIG_SPRD_WATCHDOG) += sprd_wdt.o

# AVR32 Architecture
obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o
diff --git a/drivers/watchdog/sprd_wdt.c b/drivers/watchdog/sprd_wdt.c
new file mode 100644
index 0000000..6006bb4
--- /dev/null
+++ b/drivers/watchdog/sprd_wdt.c
@@ -0,0 +1,366 @@
+/*
+ * 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/clk.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 WDT_LOAD_LOW 0x0
+#define WDT_LOAD_HIGH 0x4
+#define WDT_CTRL 0x8
+#define WDT_INT_CLR 0xc
+#define WDT_INT_RAW 0x10
+#define WDT_INT_MSK 0x14
+#define WDT_CNT_LOW 0x18
+#define WDT_CNT_HIGH 0x1c
+#define WDT_LOCK 0x20
+#define WDT_IRQ_LOAD_LOW 0x2c
+#define WDT_IRQ_LOAD_HIGH 0x30
+
+/* WDT_CTRL */
+#define WDT_INT_EN_BIT BIT(0)
+#define WDT_CNT_EN_BIT BIT(1)
+#define WDT_NEW_VER_EN BIT(2)
+#define WDT_RST_EN_BIT BIT(3)
+
+/* WDT_INT_CLR */
+#define WDT_INT_CLEAR_BIT BIT(0)
+#define WDT_RST_CLEAR_BIT BIT(3)
+
+/* WDT_INT_RAW */
+#define WDT_INT_RAW_BIT BIT(0)
+#define WDT_RST_RAW_BIT BIT(3)
+#define WDT_LD_BUSY_BIT BIT(4)
+
+#define WDT_CLK 32768
+#define WDT_UNLOCK_KEY 0xe551
+#define WDT_IRQ_TMROUT_OFFSET 0x3
+
+#define WDT_CNT_VALUE_SIZE 16
+#define WDT_CNT_VALUE_MASK GENMASK(15, 0)
+#define WDT_LOAD_TIMEOUT_NUM 10000
+
+struct sprd_wdt {
+ void __iomem *base;
+ struct watchdog_device wdd;
+ struct clk *enable;
+ struct clk *rtc_enable;
+ u32 irq_tmr_out;
+ u32 rst_tmr_out;
+ unsigned 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 + WDT_LOCK);
+}
+
+static inline void sprd_wdt_unlock(void __iomem *addr)
+{
+ writel_relaxed(WDT_UNLOCK_KEY, addr + 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(WDT_INT_CLEAR_BIT, wdt->base + 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 + WDT_CNT_HIGH) << WDT_CNT_VALUE_SIZE;
+ val |= readl_relaxed(wdt->base + WDT_CNT_LOW) & WDT_CNT_VALUE_MASK;
+
+ return val;
+}
+
+static int sprd_wdt_load_value(struct sprd_wdt *wdt, u32 rst_value,
+ u32 irq_value)
+{
+ u32 val, cnt = 0;
+
+ sprd_wdt_unlock(wdt->base);
+ writel_relaxed((rst_value >> WDT_CNT_VALUE_SIZE) & WDT_CNT_VALUE_MASK,
+ wdt->base + WDT_LOAD_HIGH);
+ writel_relaxed((rst_value & WDT_CNT_VALUE_MASK),
+ wdt->base + WDT_LOAD_LOW);
+ writel_relaxed((irq_value >> WDT_CNT_VALUE_SIZE) & WDT_CNT_VALUE_MASK,
+ wdt->base + WDT_IRQ_LOAD_HIGH);
+ writel_relaxed(irq_value & WDT_CNT_VALUE_MASK,
+ wdt->base + 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 + WDT_INT_RAW);
+ if (!(val & WDT_LD_BUSY_BIT))
+ break;
+
+ cpu_relax();
+ } while (cnt++ < WDT_LOAD_TIMEOUT_NUM);
+
+ if (cnt == WDT_LOAD_TIMEOUT_NUM)
+ return -EBUSY;
+ return 0;
+}
+
+static void sprd_wdt_enable(struct sprd_wdt *wdt)
+{
+ u32 val;
+
+ clk_prepare_enable(wdt->enable);
+ clk_prepare_enable(wdt->rtc_enable);
+
+ sprd_wdt_unlock(wdt->base);
+ val = readl_relaxed(wdt->base + WDT_CTRL);
+ val |= WDT_NEW_VER_EN;
+ writel_relaxed(val, wdt->base + WDT_CTRL);
+ sprd_wdt_lock(wdt->base);
+}
+
+static void sprd_wdt_disable(struct sprd_wdt *wdt)
+{
+ sprd_wdt_unlock(wdt->base);
+ writel_relaxed(0x0, wdt->base + WDT_CTRL);
+ sprd_wdt_lock(wdt->base);
+
+ clk_disable(wdt->enable);
+ clk_disable(wdt->rtc_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, wdt->rst_tmr_out * WDT_CLK,
+ (wdt->rst_tmr_out - wdt->irq_tmr_out) * WDT_CLK);
+ if (ret)
+ return ret;
+
+ sprd_wdt_unlock(wdt->base);
+ val = readl_relaxed(wdt->base + WDT_CTRL);
+ val |= WDT_CNT_EN_BIT | WDT_INT_EN_BIT | WDT_RST_EN_BIT;
+ writel_relaxed(val, wdt->base + WDT_CTRL);
+ sprd_wdt_lock(wdt->base);
+
+ 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 + WDT_CTRL);
+ val &= ~(WDT_CNT_EN_BIT | WDT_RST_EN_BIT | WDT_INT_EN_BIT);
+ writel_relaxed(val, wdt->base + 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 < wdt->irq_tmr_out) {
+ dev_err(wdd->parent, "wrong timeout value\n");
+ return -EINVAL;
+ }
+
+ return sprd_wdt_load_value(wdt, timeout * WDT_CLK,
+ (timeout - wdt->irq_tmr_out) * WDT_CLK);
+}
+
+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 / WDT_CLK;
+
+ 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,
+ .get_timeleft = sprd_wdt_get_timeleft,
+};
+
+static const struct watchdog_info sprd_wdt_info = {
+ .options = WDIOF_SETTIMEOUT | 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;
+ u32 rst_tmr_out;
+ int ret;
+
+ wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
+ if (!wdt)
+ return -ENOMEM;
+
+ wdt_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!wdt_res) {
+ dev_err(&pdev->dev, "failed to memory resource\n");
+ return -ENOMEM;
+ }
+
+ wdt->base = devm_ioremap_nocache(&pdev->dev, wdt_res->start,
+ resource_size(wdt_res));
+ if (!wdt->base)
+ return -ENOMEM;
+
+ if (of_property_read_u32(pdev->dev.of_node, "timeout-sec",
+ &rst_tmr_out)) {
+ dev_err(&pdev->dev, "can't get reset timeout\n");
+ return -EINVAL;
+ }
+
+ 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->rst_tmr_out = rst_tmr_out;
+ wdt->irq_tmr_out = rst_tmr_out - WDT_IRQ_TMROUT_OFFSET;
+ wdt->wdd.info = &sprd_wdt_info;
+ wdt->wdd.ops = &sprd_wdt_ops;
+ wdt->wdd.min_timeout = 1;
+ wdt->wdd.max_timeout = rst_tmr_out;
+ wdt->wdd.parent = &pdev->dev;
+ set_bit(WDOG_HW_RUNNING, &wdt->wdd.status);
+
+ watchdog_init_timeout(&wdt->wdd, 0, &pdev->dev);
+
+ ret = watchdog_register_device(&wdt->wdd);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to register watchdog\n");
+ return ret;
+ }
+
+ platform_set_drvdata(pdev, wdt);
+
+ sprd_wdt_enable(wdt);
+
+ return 0;
+}
+
+static int sprd_wdt_remove(struct platform_device *pdev)
+{
+ struct sprd_wdt *wdt = platform_get_drvdata(pdev);
+
+ watchdog_unregister_device(&wdt->wdd);
+
+ return 0;
+}
+
+static int __maybe_unused sprd_wdt_pm_suspend(struct device *dev)
+{
+ struct sprd_wdt *wdt = dev_get_drvdata(dev);
+
+ sprd_wdt_stop(&wdt->wdd);
+ sprd_wdt_disable(wdt);
+
+ return 0;
+}
+
+static int __maybe_unused sprd_wdt_pm_resume(struct device *dev)
+{
+ struct sprd_wdt *wdt = dev_get_drvdata(dev);
+
+ sprd_wdt_enable(wdt);
+ sprd_wdt_start(&wdt->wdd);
+
+ 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,
+ .remove = sprd_wdt_remove,
+ .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");
--
1.9.1
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