watchdog: qcom: add support for KPSS WDT

Add a driver for the watchdog timer block found in the Krait Processor
Subsystem (KPSS) on the MSM8960, APQ8064, and IPQ8064.

Signed-off-by: Josh Cartwright <joshc@codeaurora.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 786f8c8338fb1d1d74d15b4369273a5695b44299..17b39b8a252017df989ff66145cac23dda92b09f 100644 (file)
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -461,6 +461,19 @@ config TEGRA_WATCHDOG
          To compile this driver as a module, choose M here: the
          module will be called tegra_wdt.
 
+config QCOM_WDT
+       tristate "QCOM watchdog"
+       depends on HAS_IOMEM
+       depends on ARCH_QCOM
+       select WATCHDOG_CORE
+       help
+         Say Y here to include Watchdog timer support for the watchdog found
+         on QCOM chipsets.  Currently supported targets are the MSM8960,
+         APQ8064, and IPQ8064.
+
+         To compile this driver as a module, choose M here: the
+         module will be called qcom_wdt.
+
 # AVR32 Architecture
 
 config AT32AP700X_WDT

diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 82af9956f96a2a4582b31a85c9b229f6e7ff887a..44f5d6842fc64e2d209e49e0dfc35ec8f1c5c165 100644 (file)
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -58,6 +58,7 @@ obj-$(CONFIG_RETU_WATCHDOG) += retu_wdt.o
 obj-$(CONFIG_BCM2835_WDT) += bcm2835_wdt.o
 obj-$(CONFIG_MOXART_WDT) += moxart_wdt.o
 obj-$(CONFIG_SIRFSOC_WATCHDOG) += sirfsoc_wdt.o
+obj-$(CONFIG_QCOM_WDT) += qcom-wdt.o
 obj-$(CONFIG_BCM_KONA_WDT) += bcm_kona_wdt.o
 obj-$(CONFIG_TEGRA_WATCHDOG) += tegra_wdt.o
 

diff --git a/drivers/watchdog/qcom-wdt.c b/drivers/watchdog/qcom-wdt.c
new file mode 100644 (file)
index 0000000..68db322
--- /dev/null
+++ b/drivers/watchdog/qcom-wdt.c
@@ -0,0 +1,186 @@
+/* Copyright (c) 2014, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only 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/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/watchdog.h>
+
+#define WDT_RST                0x0
+#define WDT_EN         0x8
+#define WDT_BITE_TIME  0x24
+
+struct qcom_wdt {
+       struct watchdog_device  wdd;
+       struct clk              *clk;
+       unsigned long           rate;
+       void __iomem            *base;
+};
+
+static inline
+struct qcom_wdt *to_qcom_wdt(struct watchdog_device *wdd)
+{
+       return container_of(wdd, struct qcom_wdt, wdd);
+}
+
+static int qcom_wdt_start(struct watchdog_device *wdd)
+{
+       struct qcom_wdt *wdt = to_qcom_wdt(wdd);
+
+       writel(0, wdt->base + WDT_EN);
+       writel(1, wdt->base + WDT_RST);
+       writel(wdd->timeout * wdt->rate, wdt->base + WDT_BITE_TIME);
+       writel(1, wdt->base + WDT_EN);
+       return 0;
+}
+
+static int qcom_wdt_stop(struct watchdog_device *wdd)
+{
+       struct qcom_wdt *wdt = to_qcom_wdt(wdd);
+
+       writel(0, wdt->base + WDT_EN);
+       return 0;
+}
+
+static int qcom_wdt_ping(struct watchdog_device *wdd)
+{
+       struct qcom_wdt *wdt = to_qcom_wdt(wdd);
+
+       writel(1, wdt->base + WDT_RST);
+       return 0;
+}
+
+static int qcom_wdt_set_timeout(struct watchdog_device *wdd,
+                               unsigned int timeout)
+{
+       wdd->timeout = timeout;
+       return qcom_wdt_start(wdd);
+}
+
+static const struct watchdog_ops qcom_wdt_ops = {
+       .start          = qcom_wdt_start,
+       .stop           = qcom_wdt_stop,
+       .ping           = qcom_wdt_ping,
+       .set_timeout    = qcom_wdt_set_timeout,
+       .owner          = THIS_MODULE,
+};
+
+static const struct watchdog_info qcom_wdt_info = {
+       .options        = WDIOF_KEEPALIVEPING
+                       | WDIOF_MAGICCLOSE
+                       | WDIOF_SETTIMEOUT,
+       .identity       = KBUILD_MODNAME,
+};
+
+static int qcom_wdt_probe(struct platform_device *pdev)
+{
+       struct qcom_wdt *wdt;
+       struct resource *res;
+       int ret;
+
+       wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
+       if (!wdt)
+               return -ENOMEM;
+
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       wdt->base = devm_ioremap_resource(&pdev->dev, res);
+       if (IS_ERR(wdt->base))
+               return PTR_ERR(wdt->base);
+
+       wdt->clk = devm_clk_get(&pdev->dev, NULL);
+       if (IS_ERR(wdt->clk)) {
+               dev_err(&pdev->dev, "failed to get input clock\n");
+               return PTR_ERR(wdt->clk);
+       }
+
+       ret = clk_prepare_enable(wdt->clk);
+       if (ret) {
+               dev_err(&pdev->dev, "failed to setup clock\n");
+               return ret;
+       }
+
+       /*
+        * We use the clock rate to calculate the max timeout, so ensure it's
+        * not zero to avoid a divide-by-zero exception.
+        *
+        * WATCHDOG_CORE assumes units of seconds, if the WDT is clocked such
+        * that it would bite before a second elapses it's usefulness is
+        * limited.  Bail if this is the case.
+        */
+       wdt->rate = clk_get_rate(wdt->clk);
+       if (wdt->rate == 0 ||
+           wdt->rate > 0x10000000U) {
+               dev_err(&pdev->dev, "invalid clock rate\n");
+               ret = -EINVAL;
+               goto err_clk_unprepare;
+       }
+
+       wdt->wdd.dev = &pdev->dev;
+       wdt->wdd.info = &qcom_wdt_info;
+       wdt->wdd.ops = &qcom_wdt_ops;
+       wdt->wdd.min_timeout = 1;
+       wdt->wdd.max_timeout = 0x10000000U / wdt->rate;
+
+       /*
+        * If 'timeout-sec' unspecified in devicetree, assume a 30 second
+        * default, unless the max timeout is less than 30 seconds, then use
+        * the max instead.
+        */
+       wdt->wdd.timeout = min(wdt->wdd.max_timeout, 30U);
+       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");
+               goto err_clk_unprepare;
+       }
+
+       platform_set_drvdata(pdev, wdt);
+       return 0;
+
+err_clk_unprepare:
+       clk_disable_unprepare(wdt->clk);
+       return ret;
+}
+
+static int qcom_wdt_remove(struct platform_device *pdev)
+{
+       struct qcom_wdt *wdt = platform_get_drvdata(pdev);
+
+       watchdog_unregister_device(&wdt->wdd);
+       clk_disable_unprepare(wdt->clk);
+       return 0;
+}
+
+static const struct of_device_id qcom_wdt_of_table[] = {
+       { .compatible = "qcom,kpss-wdt-msm8960", },
+       { .compatible = "qcom,kpss-wdt-apq8064", },
+       { .compatible = "qcom,kpss-wdt-ipq8064", },
+       { },
+};
+MODULE_DEVICE_TABLE(of, qcom_wdt_of_table);
+
+static struct platform_driver qcom_watchdog_driver = {
+       .probe  = qcom_wdt_probe,
+       .remove = qcom_wdt_remove,
+       .driver = {
+               .name           = KBUILD_MODNAME,
+               .of_match_table = qcom_wdt_of_table,
+       },
+};
+module_platform_driver(qcom_watchdog_driver);
+
+MODULE_DESCRIPTION("QCOM KPSS Watchdog Driver");
+MODULE_LICENSE("GPL v2");