[PATCH] drivers: watchdog: Add DaVinci's watchdog support

[Bastien Curutchet]

Add support for the DaVinci's watchdog timer

Signed-off-by: Bastien Curutchet <bastien.curutchet at bootlin.com>
---
 drivers/watchdog/Kconfig       |   7 ++
 drivers/watchdog/Makefile      |   1 +
 drivers/watchdog/davinci_wdt.c | 131 +++++++++++++++++++++++++++++++++
 3 files changed, 139 insertions(+)
 create mode 100644 drivers/watchdog/davinci_wdt.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 0c3e991331..a1c50b3f1f 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -169,6 +169,13 @@ config WDT_CORTINA
 	  This driver support all CPU ISAs supported by Cortina
 	  Access CAxxxx SoCs.
 
+config WDT_DAVINCI
+	bool "DaVinci watchdog timer support"
+	depends on WDT
+	help
+	  Select this to enable the watchdog timer for DaVinci SoCs such as the
+	  OMAP-L138.
+
 config WDT_GPIO
 	bool "External gpio watchdog support"
 	depends on WDT
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 7b39adcf0f..ad3053998a 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -29,6 +29,7 @@ obj-$(CONFIG_WDT_BOOKE) += booke_wdt.o
 obj-$(CONFIG_WDT_CORTINA) += cortina_wdt.o
 obj-$(CONFIG_WDT_ORION) += orion_wdt.o
 obj-$(CONFIG_WDT_CDNS) += cdns_wdt.o
+obj-$(CONFIG_WDT_DAVINCI) += davinci_wdt.o
 obj-$(CONFIG_WDT_FTWDT010) += ftwdt010_wdt.o
 obj-$(CONFIG_WDT_GPIO) += gpio_wdt.o
 obj-$(CONFIG_WDT_MAX6370) += max6370_wdt.o
diff --git a/drivers/watchdog/davinci_wdt.c b/drivers/watchdog/davinci_wdt.c
new file mode 100644
index 0000000000..fa8d7842e9
--- /dev/null
+++ b/drivers/watchdog/davinci_wdt.c
@@ -0,0 +1,131 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * DaVinci Watchdog driver
+ *
+ */
+
+#include <asm/io.h>
+#include <clk.h>
+#include <dm.h>
+#include <wdt.h>
+
+/* Control Register */
+#define DAVINCI_WDT_ID			0x00
+#define DAVINCI_WDT_TIM12		0x10
+#define DAVINCI_WDT_TIM34		0x14
+#define DAVINCI_WDT_PRD12		0x18
+#define DAVINCI_WDT_PRD34		0x1C
+#define DAVINCI_WDT_TCR			0x20
+#define DAVINCI_WDT_TGCR		0x24
+#define DAVINCI_WDT_WDTCR		0x28
+
+#define DAVINCI_TCR_CONT_EN		BIT(7)
+
+#define DAVINCI_TGCR_PLUSEN		BIT(4)
+#define DAVINCI_TGCR_WDT_MODE		BIT(3)
+#define DAVINCI_TGCR_TIM34RS		BIT(1)
+#define DAVINCI_TGCR_TIM12RS		BIT(0)
+
+#define DAVINCI_WDTCR_INVALID_KEY	(0x5555 << 16)
+#define DAVINCI_WDTCR_WDKEY0		(0xA5C6 << 16)
+#define DAVINCI_WDTCR_WDKEY1		(0xDA7E << 16)
+#define DAVINCI_WDTCR_WDFLAG		BIT(15)
+#define DAVINCI_WDTCR_WDEN		BIT(14)
+
+#define DEFAULT_THRESHOLD		0xA03200000
+
+struct davinci_wdt_priv {
+	void __iomem *base;
+	struct clk *ref_clk;
+};
+
+static int davinci_wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags)
+{
+	struct davinci_wdt_priv *priv = dev_get_priv(dev);
+	ulong rate = clk_get_rate(priv->ref_clk);
+	u64 threshold;
+
+	if (!rate)
+		threshold = DEFAULT_THRESHOLD;
+	else
+		threshold = rate * timeout_ms / 1000;
+
+	/* Reset control registers */
+	writel(0, priv->base + DAVINCI_WDT_TCR);
+	writel(0, priv->base + DAVINCI_WDT_TGCR);
+
+	/* Enable watchdog mode and timers */
+	writel(DAVINCI_TGCR_WDT_MODE | DAVINCI_TGCR_TIM12RS | DAVINCI_TGCR_TIM34RS,
+	       priv->base + DAVINCI_WDT_TGCR);
+
+	/* Reset counters */
+	writel(0, priv->base + DAVINCI_WDT_TIM12);
+	writel(0, priv->base + DAVINCI_WDT_TIM34);
+
+	/* Set timeout threshold */
+	writel(threshold & 0xFFFFFFFF, priv->base + DAVINCI_WDT_PRD12);
+	writel(threshold >> 32, priv->base + DAVINCI_WDT_PRD34);
+
+	/* Enable counter */
+	writel(DAVINCI_TCR_CONT_EN, priv->base + DAVINCI_WDT_TCR);
+
+	/* Go to watchdog's active state */
+	writel(DAVINCI_WDTCR_WDEN | DAVINCI_WDTCR_WDKEY0, priv->base + DAVINCI_WDT_WDTCR);
+	writel(DAVINCI_WDTCR_WDEN | DAVINCI_WDTCR_WDKEY1, priv->base + DAVINCI_WDT_WDTCR);
+
+	return 0;
+}
+
+static int davinci_wdt_expire_now(struct udevice *dev, ulong flags)
+{
+	struct davinci_wdt_priv *priv = dev_get_priv(dev);
+
+	writel(DAVINCI_WDTCR_INVALID_KEY, priv->base + DAVINCI_WDT_WDTCR);
+
+	return 0;
+}
+
+static int davinci_wdt_restart(struct udevice *dev)
+{
+	struct davinci_wdt_priv *priv = dev_get_priv(dev);
+
+	writel(DAVINCI_WDTCR_WDEN | DAVINCI_WDTCR_WDKEY0, priv->base + DAVINCI_WDT_WDTCR);
+	writel(DAVINCI_WDTCR_WDEN | DAVINCI_WDTCR_WDKEY1, priv->base + DAVINCI_WDT_WDTCR);
+
+	return 0;
+}
+
+static int davinci_wdt_probe(struct udevice *dev)
+{
+	struct davinci_wdt_priv *priv = dev_get_priv(dev);
+
+	priv->base = dev_remap_addr_index(dev, 0);
+	if (!priv->base)
+		return -EFAULT;
+
+	priv->ref_clk = devm_clk_get(dev, "ref");
+	if (IS_ERR(priv->ref_clk))
+		return PTR_ERR(priv->ref_clk);
+
+	return 0;
+}
+
+static const struct wdt_ops davinci_wdt_ops = {
+	.start = davinci_wdt_start,
+	.reset = davinci_wdt_restart,
+	.expire_now = davinci_wdt_expire_now,
+};
+
+static const struct udevice_id davinci_wdt_ids[] = {
+	{.compatible = "ti,davinci-wdt"},
+	{}
+};
+
+U_BOOT_DRIVER(davinci_wdt) = {
+	.name = "davinci_wdt",
+	.id = UCLASS_WDT,
+	.probe = davinci_wdt_probe,
+	.of_match = davinci_wdt_ids,
+	.ops = &davinci_wdt_ops,
+	.priv_auto = sizeof(struct davinci_wdt_priv),
+};
-- 
2.46.0