[PATCH] driver: watchdog: Add support for omap_wdt

Teresa Remmet t.remmet at phytec.de
Tue Nov 10 23:49:16 PST 2015 

Add support for OMAP Watchdog driver.

Based on omap_wdt Linux driver (v4.3-rc1).

Signed-off-by: Teresa Remmet <t.remmet at phytec.de>
---
 drivers/watchdog/Kconfig    |   6 ++
 drivers/watchdog/Makefile   |   1 +
 drivers/watchdog/omap_wdt.c | 199 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 206 insertions(+)
 create mode 100644 drivers/watchdog/omap_wdt.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 582c615..60a56bf 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -34,4 +34,10 @@ config WATCHDOG_JZ4740
 	help
 	  Hardware driver for the built-in watchdog timer on Ingenic jz4740 SoCs.
 
+config WATCHDOG_OMAP
+	bool "TI OMAP"
+	depends on ARCH_OMAP
+	help
+	  Add support for watchdog on the TI OMAP SoC.
+
 endif
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 1e63c49..e3afe1c 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -1,5 +1,6 @@
 obj-$(CONFIG_WATCHDOG) += wd_core.o
 obj-$(CONFIG_WATCHDOG_DAVINCI) += davinci_wdt.o
+obj-$(CONFIG_WATCHDOG_OMAP) += omap_wdt.o
 obj-$(CONFIG_WATCHDOG_MXS28) += im28wd.o
 obj-$(CONFIG_WATCHDOG_JZ4740) += jz4740.o
 obj-$(CONFIG_WATCHDOG_IMX_RESET_SOURCE) += imxwd.o
diff --git a/drivers/watchdog/omap_wdt.c b/drivers/watchdog/omap_wdt.c
new file mode 100644
index 0000000..aa71a68
--- /dev/null
+++ b/drivers/watchdog/omap_wdt.c
@@ -0,0 +1,199 @@
+/*
+ * omap_wdt.c
+ *
+ * Watchdog driver for the TI OMAP 16xx & 24xx/34xx 32KHz (non-secure) watchdog
+ *
+ * Copyright (c) 2015 Phytec Messtechnik GmbH
+ * Author: Teresa Remmet <t.remmet at phytec.de>
+ *
+ * Based on Linux Kernel OMAP WTD driver:
+ *
+ * Author: MontaVista Software, Inc.
+ *	 <gdavis at mvista.com> or <source at mvista.com>
+ *
+ * 2003 (c) MontaVista Software, Inc. This file is licensed under the
+ * terms of the GNU General Public License version 2. This program is
+ * licensed "as is" without any warranty of any kind, whether express
+ * or implied.
+ *
+ * History:
+ *
+ * 20030527: George G. Davis <gdavis at mvista.com>
+ *	Initially based on linux-2.4.19-rmk7-pxa1/drivers/char/sa1100_wdt.c
+ *	(c) Copyright 2000 Oleg Drokin <green at crimea.edu>
+ *	Based on SoftDog driver by Alan Cox <alan at lxorguk.ukuu.org.uk>
+ *
+ * Copyright (c) 2004 Texas Instruments.
+ *	1. Modified to support OMAP1610 32-KHz watchdog timer
+ *	2. Ported to 2.6 kernel
+ *
+ * Copyright (c) 2005 David Brownell
+ *	Use the driver model and standard identifiers; handle bigger timeouts.
+ */
+
+#include <common.h>
+#include <init.h>
+#include <io.h>
+#include <of.h>
+#include <errno.h>
+#include <malloc.h>
+#include <watchdog.h>
+
+#define OMAP_WATCHDOG_REV		(0x00)
+#define OMAP_WATCHDOG_SYS_CONFIG	(0x10)
+#define OMAP_WATCHDOG_STATUS		(0x14)
+#define OMAP_WATCHDOG_CNTRL		(0x24)
+#define OMAP_WATCHDOG_CRR		(0x28)
+#define OMAP_WATCHDOG_LDR		(0x2c)
+#define OMAP_WATCHDOG_TGR		(0x30)
+#define OMAP_WATCHDOG_WPS		(0x34)
+#define OMAP_WATCHDOG_SPR		(0x48)
+
+#define TIMER_MARGIN_DEFAULT	60	/* 60 secs */
+
+#define PTV			0	/* prescale */
+#define GET_WLDR_VAL(secs)      (0xffffffff - ((secs) * (32768/(1<<PTV))) + 1)
+#define GET_WCCR_SECS(val)      ((0xffffffff - (val) + 1) / (32768/(1<<PTV)))
+
+#define to_omap_wdt_dev(_wdog)	container_of(_wdog, struct omap_wdt_dev, wdog)
+
+struct omap_wdt_dev {
+	struct watchdog wdog;
+	void __iomem    *base;
+	int		wdt_trgr_pattern;
+	unsigned	timeout;
+};
+
+static void omap_wdt_reload(struct omap_wdt_dev *wdev)
+{
+	void __iomem *base = wdev->base;
+
+	/* wait for posted write to complete */
+	while ((readl(base + OMAP_WATCHDOG_WPS)) & 0x08);
+
+	wdev->wdt_trgr_pattern = ~wdev->wdt_trgr_pattern;
+	writel(wdev->wdt_trgr_pattern, (base + OMAP_WATCHDOG_TGR));
+
+	/* wait for posted write to complete */
+	while ((readl(base + OMAP_WATCHDOG_WPS)) & 0x08);
+	/* reloaded WCRR from WLDR */
+}
+
+static void omap_wdt_enable(struct omap_wdt_dev *wdev)
+{
+	void __iomem *base = wdev->base;
+
+	/* Sequence to enable the watchdog */
+	writel(0xBBBB, base + OMAP_WATCHDOG_SPR);
+	while ((readl(base + OMAP_WATCHDOG_WPS)) & 0x10);
+
+	writel(0x4444, base + OMAP_WATCHDOG_SPR);
+	while ((readl(base + OMAP_WATCHDOG_WPS)) & 0x10);
+}
+
+static void omap_wdt_disable(struct omap_wdt_dev *wdev)
+{
+	void __iomem *base = wdev->base;
+
+	/* sequence required to disable watchdog */
+	writel(0xAAAA, base + OMAP_WATCHDOG_SPR);	/* TIMER_MODE */
+	while (readl(base + OMAP_WATCHDOG_WPS) & 0x10);
+
+	writel(0x5555, base + OMAP_WATCHDOG_SPR);	/* TIMER_MODE */
+	while (readl(base + OMAP_WATCHDOG_WPS) & 0x10);
+}
+
+static void omap_wdt_set_timer(struct omap_wdt_dev *wdev,
+				   unsigned int timeout)
+{
+	u32 pre_margin = GET_WLDR_VAL(timeout);
+	void __iomem *base = wdev->base;
+
+	/* just count up at 32 KHz */
+	while (readl(base + OMAP_WATCHDOG_WPS) & 0x04);
+
+	writel(pre_margin, base + OMAP_WATCHDOG_LDR);
+	while (readl(base + OMAP_WATCHDOG_WPS) & 0x04);
+
+}
+
+static void omap_wdt_init(struct omap_wdt_dev *wdev)
+{
+	void __iomem *base = wdev->base;
+
+	/*
+	 * Make sure the watchdog is disabled. This is unfortunately required
+	 * because writing to various registers with the watchdog running has no
+	 * effect.
+	 */
+	omap_wdt_disable(wdev);
+
+	/* initialize prescaler */
+	while (readl(base + OMAP_WATCHDOG_WPS) & 0x01);
+
+	writel((1 << 5) | (PTV << 2), base + OMAP_WATCHDOG_CNTRL);
+	while (readl(base + OMAP_WATCHDOG_WPS) & 0x01);
+
+	omap_wdt_set_timer(wdev, wdev->timeout);
+	omap_wdt_reload(wdev); /* trigger loading of new timeout value */
+}
+
+static int omap_wdt_set_timeout(struct watchdog *wdog,
+				unsigned int timeout)
+{
+	struct omap_wdt_dev *wdev = to_omap_wdt_dev(wdog);
+
+	omap_wdt_disable(wdev);
+	omap_wdt_set_timer(wdev, timeout);
+	omap_wdt_enable(wdev);
+	omap_wdt_reload(wdev);
+	wdev->timeout = timeout;
+
+	return 0;
+}
+
+static int omap_wdt_probe(struct device_d *dev)
+{
+	struct omap_wdt_dev *wdev;
+	int ret;
+
+	wdev = xzalloc(sizeof(*wdev));
+	wdev->wdog.set_timeout	= omap_wdt_set_timeout;
+	wdev->wdt_trgr_pattern	= 0x1234;
+
+	/* reserve static register mappings */
+	wdev->base = dev_request_mem_region(dev, 0);
+	if (IS_ERR(wdev->base)) {
+		ret =  PTR_ERR(wdev->base);
+		goto error;
+	}
+
+	wdev->timeout = TIMER_MARGIN_DEFAULT;
+
+	ret = watchdog_register(&wdev->wdog);
+	if (ret)
+		goto error;
+
+	pr_info("OMAP Watchdog Timer Rev 0x%02x\n",
+		readl(wdev->base + OMAP_WATCHDOG_REV) & 0xFF);
+
+	omap_wdt_init(wdev);
+
+	return 0;
+
+error:
+	free(wdev);
+	return ret;
+}
+
+static const struct of_device_id omap_wdt_of_match[] = {
+	{ .compatible = "ti,omap3-wdt", },
+	{},
+};
+
+static struct driver_d omap_wdt_driver = {
+	.probe		= omap_wdt_probe,
+	.name	= "omap_wdt",
+	.of_compatible = DRV_OF_COMPAT(omap_wdt_of_match),
+};
+device_platform_driver(omap_wdt_driver);
-- 
1.9.1

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