[RFC PATCH 1/3] watchdog: Add Meson GXBB Watchdog Driver

[Neil Armstrong <narmstrong@baylibre.com>]

Add watchdog specific driver for Amlogic Meson GXBB SoC.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
---
 drivers/watchdog/Makefile         |   1 +
 drivers/watchdog/meson_gxbb_wdt.c | 287 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 288 insertions(+)
 create mode 100644 drivers/watchdog/meson_gxbb_wdt.c

diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 9bde095..7679d93 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -68,6 +68,7 @@ obj-$(CONFIG_QCOM_WDT) += qcom-wdt.o
 obj-$(CONFIG_BCM_KONA_WDT) += bcm_kona_wdt.o
 obj-$(CONFIG_TEGRA_WATCHDOG) += tegra_wdt.o
 obj-$(CONFIG_MESON_WATCHDOG) += meson_wdt.o
+obj-$(CONFIG_MESON_WATCHDOG) += meson_gxbb_wdt.o
 obj-$(CONFIG_MEDIATEK_WATCHDOG) += mtk_wdt.o
 obj-$(CONFIG_DIGICOLOR_WATCHDOG) += digicolor_wdt.o
 obj-$(CONFIG_LPC18XX_WATCHDOG) += lpc18xx_wdt.o
diff --git a/drivers/watchdog/meson_gxbb_wdt.c b/drivers/watchdog/meson_gxbb_wdt.c
new file mode 100644
index 0000000..0c7c0d9
--- /dev/null
+++ b/drivers/watchdog/meson_gxbb_wdt.c
@@ -0,0 +1,287 @@
+/*
+ * This file is provided under a dual BSD/GPLv2 license.  When using or
+ * redistributing this file, you may do so under either license.
+ *
+ * GPL LICENSE SUMMARY
+ *
+ * Copyright (c) 2016 BayLibre, SAS.
+ * Author: Neil Armstrong <narmstrong@baylibre.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ * The full GNU General Public License is included in this distribution
+ * in the file called COPYING.
+ *
+ * BSD LICENSE
+ *
+ * Copyright (c) 2016 BayLibre, SAS.
+ * Author: Neil Armstrong <narmstrong@baylibre.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *   * Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in
+ *     the documentation and/or other materials provided with the
+ *     distribution.
+ *   * Neither the name of Intel Corporation nor the names of its
+ *     contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/clk.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/watchdog.h>
+
+#define DEFAULT_TIMEOUT	10	/* seconds */
+
+#define GXBB_WDT_CTRL_REG	0x0
+#define GXBB_WDT_CTRL1_REG	0x4
+#define GXBB_WDT_TCNT_REG	0x8
+#define GXBB_WDT_RSET_REG	0xc
+
+#define GXBB_WDT_CTRL_EE_RESET_NOW	BIT(26)
+
+#define GXBB_WDT_CTRL_CLKDIV_EN	BIT(25)
+#define GXBB_WDT_CTRL_CLK_EN	BIT(24)
+#define GXBB_WDT_CTRL_IRQ_EN	BIT(23)
+#define GXBB_WDT_CTRL_EE_RESET	BIT(21)
+#define GXBB_WDT_CTRL_XTAL_SEL	(0)
+#define GXBB_WDT_CTRL_CLK81_SEL	BIT(19)
+#define GXBB_WDT_CTRL_EN	BIT(18)
+#define GXBB_WDT_CTRL_DIV_MASK	(BIT(18)-1)
+
+#define GXBB_WDT_CTRL1_GPIO_PULSE	BIT(17)
+#define GXBB_WDT_CTRL1_GPIO_POL_RESET_0	BIT(16)
+#define GXBB_WDT_CTRL1_GPIO_POL_RESET_1	(0)
+#define GXBB_WDT_CTRL1_GPIO_PULSE_CNT	(BIT(16)-1)
+
+#define GXBB_WDT_TCNT_SETUP_MASK	(BIT(16)-1)
+#define GXBB_WDT_TCNT_CNT_SHIFT		16
+
+struct meson_gxbb_wdt {
+	void __iomem *reg_base;
+	struct watchdog_device wdt_dev;
+	struct clk *clk;
+};
+
+int meson_gxbb_wdt_start(struct watchdog_device *wdt_dev)
+{
+	struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev);
+
+	writel(readl(data->reg_base + GXBB_WDT_CTRL_REG) | GXBB_WDT_CTRL_EN,
+		data->reg_base + GXBB_WDT_CTRL_REG);
+
+	return 0;
+}
+
+int meson_gxbb_wdt_stop(struct watchdog_device *wdt_dev)
+{
+	struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev);
+
+	writel(readl(data->reg_base + GXBB_WDT_CTRL_REG) & ~GXBB_WDT_CTRL_EN,
+		data->reg_base + GXBB_WDT_CTRL_REG);
+
+	return 0;
+}
+
+unsigned int meson_gxbb_wdt_status(struct watchdog_device *wdt_dev)
+{
+	struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev);
+
+	return !!(readl(data->reg_base + GXBB_WDT_CTRL_REG) & GXBB_WDT_CTRL_EN);
+}
+
+int meson_gxbb_wdt_ping(struct watchdog_device *wdt_dev)
+{
+	struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev);
+
+	writel(0, data->reg_base + GXBB_WDT_RSET_REG);
+
+	return 0;
+}
+
+int meson_gxbb_wdt_set_timeout(struct watchdog_device *wdt_dev,
+			       unsigned int timeout)
+{
+	struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev);
+
+	if (watchdog_active(wdt_dev))
+		meson_gxbb_wdt_stop(wdt_dev);
+
+	meson_gxbb_wdt_ping(wdt_dev);
+
+	writel(timeout*1000, data->reg_base + GXBB_WDT_TCNT_REG);
+
+	if (watchdog_active(wdt_dev))
+		meson_gxbb_wdt_start(wdt_dev);
+
+	return 0;
+}
+
+unsigned int meson_gxbb_wdt_get_timeleft(struct watchdog_device *wdt_dev)
+{
+	struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev);
+	unsigned long reg;
+
+	reg = readl(data->reg_base + GXBB_WDT_TCNT_REG);
+
+	return ((reg >> GXBB_WDT_TCNT_CNT_SHIFT)-
+			(reg & GXBB_WDT_TCNT_SETUP_MASK)) / 1000;
+}
+
+static const struct watchdog_ops meson_gxbb_wdt_ops = {
+	.start = meson_gxbb_wdt_start,
+	.stop = meson_gxbb_wdt_stop,
+	.status = meson_gxbb_wdt_status,
+	.ping = meson_gxbb_wdt_ping,
+	.set_timeout = meson_gxbb_wdt_set_timeout,
+	.get_timeleft = meson_gxbb_wdt_get_timeleft,
+};
+
+static const struct watchdog_info meson_gxbb_wdt_info = {
+	.identity = "meson-gxbb-wdt",
+	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
+};
+
+static int __maybe_unused meson_gxbb_wdt_resume(struct device *dev)
+{
+	struct meson_gxbb_wdt *data = dev_get_drvdata(dev);
+
+	if (watchdog_active(&data->wdt_dev))
+		meson_gxbb_wdt_start(&data->wdt_dev);
+
+	return 0;
+}
+
+static int __maybe_unused meson_gxbb_wdt_suspend(struct device *dev)
+{
+	struct meson_gxbb_wdt *data = dev_get_drvdata(dev);
+
+	if (watchdog_active(&data->wdt_dev))
+		meson_gxbb_wdt_stop(&data->wdt_dev);
+
+	return 0;
+}
+
+static const struct dev_pm_ops meson_gxbb_wdt_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(meson_gxbb_wdt_suspend, meson_gxbb_wdt_resume)
+};
+
+static const struct of_device_id meson_gxbb_wdt_dt_ids[] = {
+	 { .compatible = "amlogic,meson-gxbb-wdt", },
+	 { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, meson_gxbb_wdt_dt_ids);
+
+static int meson_gxbb_wdt_probe(struct platform_device *pdev)
+{
+	struct meson_gxbb_wdt *data;
+	struct resource *res;
+	int ret;
+
+	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	data->reg_base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(data->reg_base))
+		return PTR_ERR(data->reg_base);
+
+	data->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(data->clk))
+		return PTR_ERR(data->clk);
+
+	clk_prepare_enable(data->clk);
+
+	platform_set_drvdata(pdev, data);
+
+	data->wdt_dev.parent = &pdev->dev;
+	data->wdt_dev.info = &meson_gxbb_wdt_info;
+	data->wdt_dev.ops = &meson_gxbb_wdt_ops;
+	data->wdt_dev.max_hw_heartbeat_ms = GXBB_WDT_TCNT_SETUP_MASK;
+	data->wdt_dev.min_hw_heartbeat_ms = 1;
+	data->wdt_dev.timeout = DEFAULT_TIMEOUT;
+	watchdog_set_drvdata(&data->wdt_dev, data);
+
+	watchdog_init_timeout(&data->wdt_dev, DEFAULT_TIMEOUT, &pdev->dev);
+
+	ret = watchdog_register_device(&data->wdt_dev);
+	if (ret)
+		return ret;
+
+	/* Setup with 1ms timebase */
+	writel(((clk_get_rate(data->clk) / 1000) & GXBB_WDT_CTRL_DIV_MASK) |
+		GXBB_WDT_CTRL_EE_RESET |
+		GXBB_WDT_CTRL_CLK_EN |
+		GXBB_WDT_CTRL_CLKDIV_EN,
+		data->reg_base + GXBB_WDT_CTRL_REG);
+	meson_gxbb_wdt_set_timeout(&data->wdt_dev, data->wdt_dev.timeout);
+	meson_gxbb_wdt_ping(&data->wdt_dev);
+
+	return 0;
+}
+
+static int meson_gxbb_wdt_remove(struct platform_device *pdev)
+{
+	struct meson_gxbb_wdt *data = platform_get_drvdata(pdev);
+
+	watchdog_unregister_device(&data->wdt_dev);
+
+	return 0;
+}
+
+static void meson_gxbb_wdt_shutdown(struct platform_device *pdev)
+{
+	struct meson_gxbb_wdt *data = platform_get_drvdata(pdev);
+
+	meson_gxbb_wdt_stop(&data->wdt_dev);
+}
+
+static struct platform_driver meson_gxbb_wdt_driver = {
+	.probe	= meson_gxbb_wdt_probe,
+	.remove	= meson_gxbb_wdt_remove,
+	.shutdown = meson_gxbb_wdt_shutdown,
+	.driver = {
+		.name = "meson-gxbb-wdt",
+		.pm = &meson_gxbb_wdt_pm_ops,
+		.of_match_table	= meson_gxbb_wdt_dt_ids,
+	},
+};
+
+module_platform_driver(meson_gxbb_wdt_driver);
+
+MODULE_ALIAS("platform:meson-gxbb-wdt");
+MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
+MODULE_DESCRIPTION("Amlogic Meson GXBB Watchdog timer driver");
+MODULE_LICENSE("Dual BSD/GPL");
-- 
2.7.0