[U-Boot] [patch v2 1/3] watchdog: add sp805 watchdog support

[Qiang Zhao <qiang.zhao@nxp.com>]

sp805 is watchdog on some NXP layerscape SoCs, Now add its driver in uboot.
To add
	CONFIG_WDT_SP805=y
	CONFIG_WDT=y
	CONFIG_CMD_WDT=y
in defconfig to use it.

Signed-off-by: Zhao Qiang <qiang.zhao@nxp.com>
---
 MAINTAINERS                  |   1 +
 drivers/watchdog/Kconfig     |   7 ++
 drivers/watchdog/Makefile    |   1 +
 drivers/watchdog/sp805_wdt.c | 126 +++++++++++++++++++++++++++++++++++
 4 files changed, 135 insertions(+)
 create mode 100644 drivers/watchdog/sp805_wdt.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 8f237128b2..e8e7a92802 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -410,6 +410,7 @@ FREESCALE QORIQ
 M:	York Sun <york.sun@nxp.com>
 S:	Maintained
 T:	git git://git.denx.de/u-boot-fsl-qoriq.git
+F:	drivers/watchdog/sp805_wdt.c
 
 I2C
 M:	Heiko Schocher <hs@denx.de>
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index b06c5447f6..29e04630d2 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -95,6 +95,13 @@ config WDT_ORION
 	   Select this to enable Orion watchdog timer, which can be found on some
 	   Marvell Armada chips.
 
+config WDT_SP805
+	bool "SP805 watchdog timer support"
+	depends on WDT
+	help
+	   Select this to enable SP805 watchdog timer, which can be found on some
+	   nxp layerscape chips.
+
 config WDT_CDNS
 	bool "Cadence watchdog timer support"
 	depends on WDT
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 19c631bb58..eb285bde24 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -25,3 +25,4 @@ obj-$(CONFIG_BCM2835_WDT)       += bcm2835_wdt.o
 obj-$(CONFIG_WDT_ORION) += orion_wdt.o
 obj-$(CONFIG_WDT_CDNS) += cdns_wdt.o
 obj-$(CONFIG_MPC8xx_WATCHDOG) += mpc8xx_wdt.o
+obj-$(CONFIG_WDT_SP805) += sp805_wdt.o
diff --git a/drivers/watchdog/sp805_wdt.c b/drivers/watchdog/sp805_wdt.c
new file mode 100644
index 0000000000..e4d81c995d
--- /dev/null
+++ b/drivers/watchdog/sp805_wdt.c
@@ -0,0 +1,126 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Watchdog driver for SP805 on some Layerscape SoC
+ *
+ * Copyright 2019 NXP
+ */
+
+#include <asm/io.h>
+#include <common.h>
+#include <dm/device.h>
+#include <dm/fdtaddr.h>
+#include <dm/read.h>
+#include <linux/bitops.h>
+#include <watchdog.h>
+#include <wdt.h>
+
+#define WDTLOAD			0x000
+#define WDTCONTROL		0x008
+#define WDTINTCLR		0x00C
+#define WDTLOCK			0xC00
+
+#define TIME_OUT_DEFAULT_MSECS	15000
+#define TIME_OUT_MIN_MSECS	1
+#define TIME_OUT_MAX_MSECS	120000
+#define SYS_FSL_WDT_CLK_DIV	16
+#define INT_ENABLE		BIT(0)
+#define RESET_ENABLE		BIT(1)
+#define DISABLE			0
+#define UNLOCK			0x1ACCE551
+#define LOCK			0x00000001
+#define INT_MASK		BIT(0)
+
+DECLARE_GLOBAL_DATA_PTR;
+
+struct sp805_wdt_priv {
+	void __iomem *reg;
+	u32 timeout;
+};
+
+static int sp805_wdt_reset(struct udevice *dev)
+{
+	struct sp805_wdt_priv *priv = dev_get_priv(dev);
+
+	writel(UNLOCK, priv->reg + WDTLOCK);
+	writel(INT_MASK, priv->reg + WDTINTCLR);
+	writel(LOCK, priv->reg + WDTLOCK);
+	readl(priv->reg + WDTLOCK);
+
+	return 0;
+}
+
+static int sp805_wdt_start(struct udevice *dev, u64 timeout, ulong flags)
+{
+	u32 load_value;
+	struct sp805_wdt_priv *priv = dev_get_priv(dev);
+
+	priv->timeout = (u32)timeout;
+	if (timeout < TIME_OUT_MIN_MSECS || timeout > TIME_OUT_MAX_MSECS)
+		priv->timeout = TIME_OUT_DEFAULT_MSECS;
+	/* sp805 runs counter with given value twice, so when the timeout is
+	 * set 15s, the gd->bus_clk is less than 9162MHz, the load_value will
+	 * not overflow.
+	 */
+	load_value = (gd->bus_clk) /
+		(2 * 1000 * SYS_FSL_WDT_CLK_DIV) * priv->timeout;
+
+	writel(UNLOCK, priv->reg + WDTLOCK);
+	writel(load_value, priv->reg + WDTLOAD);
+	writel(INT_MASK, priv->reg + WDTINTCLR);
+	writel(INT_ENABLE | RESET_ENABLE, priv->reg + WDTCONTROL);
+	writel(LOCK, priv->reg + WDTLOCK);
+	readl(priv->reg + WDTLOCK);
+
+	return 0;
+}
+
+static int sp805_wdt_stop(struct udevice *dev)
+{
+	struct sp805_wdt_priv *priv = dev_get_priv(dev);
+
+	writel(UNLOCK, priv->reg + WDTLOCK);
+	writel(DISABLE, priv->reg + WDTCONTROL);
+	writel(LOCK, priv->reg + WDTLOCK);
+	readl(priv->reg + WDTLOCK);
+
+	return 0;
+}
+
+static int sp805_wdt_probe(struct udevice *dev)
+{
+	debug("%s: Probing wdt%u\n", __func__, dev->seq);
+
+	return 0;
+}
+
+static int sp805_wdt_ofdata_to_platdata(struct udevice *dev)
+{
+	struct sp805_wdt_priv *priv = dev_get_priv(dev);
+
+	priv->reg = (void __iomem *)dev_read_addr(dev);
+	if (IS_ERR(priv->reg))
+		return PTR_ERR(priv->reg);
+
+	return 0;
+}
+
+static const struct wdt_ops sp805_wdt_ops = {
+	.start = sp805_wdt_start,
+	.reset = sp805_wdt_reset,
+	.stop = sp805_wdt_stop,
+};
+
+static const struct udevice_id sp805_wdt_ids[] = {
+	{ .compatible = "arm,sp805-wdt" },
+	{}
+};
+
+U_BOOT_DRIVER(sp805_wdt) = {
+	.name = "sp805_wdt",
+	.id = UCLASS_WDT,
+	.of_match = sp805_wdt_ids,
+	.probe = sp805_wdt_probe,
+	.priv_auto_alloc_size = sizeof(struct sp805_wdt_priv),
+	.ofdata_to_platdata = sp805_wdt_ofdata_to_platdata,
+	.ops = &sp805_wdt_ops,
+};
-- 
2.17.1