[PATCH 3/4] watchdog: octeontx_wdt: Add support for start and stop

[Stefan Roese]

From: Suneel Garapati <sgarapati at marvell.com>

This patch enhances the Octeon TX/TX2 watchdog driver to fully enable
the WDT. With this changes, the "wdt" command is now also supported
on these platforms.

Signed-off-by: Suneel Garapati <sgarapati at marvell.com>
Signed-off-by: Stefan Roese <sr at denx.de>
Cc: Aaron Williams <awilliams at marvell.com>
Cc: Suneel Garapati <sgarapati at marvell.com>
Cc: Chandrakala Chavva <cchavva at marvell.com>
---
 drivers/watchdog/octeontx_wdt.c | 88 +++++++++++++++++++++++++++++++--
 1 file changed, 83 insertions(+), 5 deletions(-)

diff --git a/drivers/watchdog/octeontx_wdt.c b/drivers/watchdog/octeontx_wdt.c
index 1e0670e0c5..88708dc5e1 100644
--- a/drivers/watchdog/octeontx_wdt.c
+++ b/drivers/watchdog/octeontx_wdt.c
@@ -5,25 +5,90 @@
  * https://spdx.org/licenses
  */
 
+#include <clk.h>
 #include <dm.h>
 #include <errno.h>
 #include <wdt.h>
 #include <asm/io.h>
+#include <linux/bitfield.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
+#define CORE0_WDOG_OFFSET	0x40000
 #define CORE0_POKE_OFFSET	0x50000
 #define CORE0_POKE_OFFSET_MASK	0xfffffULL
 
+#define WDOG_MODE		GENMASK_ULL(1, 0)
+#define WDOG_LEN		GENMASK_ULL(19, 4)
+#define WDOG_CNT		GENMASK_ULL(43, 20)
+
 struct octeontx_wdt {
 	void __iomem *reg;
+	struct clk clk;
 };
 
+static int octeontx_wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags)
+{
+	struct octeontx_wdt *priv = dev_get_priv(dev);
+	u64 clk_rate, val;
+	u64 tout_wdog;
+
+	clk_rate = clk_get_rate(&priv->clk);
+	if (IS_ERR_VALUE(clk_rate))
+		return -EINVAL;
+
+	/* Watchdog counts in 1024 cycle steps */
+	tout_wdog = (clk_rate * timeout_ms / 1000) >> 10;
+
+	/*
+	 * We can only specify the upper 16 bits of a 24 bit value.
+	 * Round up
+	 */
+	tout_wdog = (tout_wdog + 0xff) >> 8;
+
+	/* If the timeout overflows the hardware limit, set max */
+	if (tout_wdog >= 0x10000)
+		tout_wdog = 0xffff;
+
+	val = FIELD_PREP(WDOG_MODE, 0x3) |
+		FIELD_PREP(WDOG_LEN, tout_wdog) |
+		FIELD_PREP(WDOG_CNT, tout_wdog << 8);
+	writeq(val, priv->reg + CORE0_WDOG_OFFSET);
+
+	return 0;
+}
+
+static int octeontx_wdt_stop(struct udevice *dev)
+{
+	struct octeontx_wdt *priv = dev_get_priv(dev);
+
+	writeq(0, priv->reg + CORE0_WDOG_OFFSET);
+
+	return 0;
+}
+
+static int octeontx_wdt_expire_now(struct udevice *dev, ulong flags)
+{
+	octeontx_wdt_stop(dev);
+
+	/* Start with 100ms timeout to expire immediately */
+	octeontx_wdt_start(dev, 100, flags);
+
+	return 0;
+}
+
 static int octeontx_wdt_reset(struct udevice *dev)
 {
 	struct octeontx_wdt *priv = dev_get_priv(dev);
 
-	writeq(~0ULL, priv->reg);
+	writeq(~0ULL, priv->reg + CORE0_POKE_OFFSET);
+
+	return 0;
+}
+
+static int octeontx_wdt_remove(struct udevice *dev)
+{
+	octeontx_wdt_stop(dev);
 
 	return 0;
 }
@@ -31,24 +96,35 @@ static int octeontx_wdt_reset(struct udevice *dev)
 static int octeontx_wdt_probe(struct udevice *dev)
 {
 	struct octeontx_wdt *priv = dev_get_priv(dev);
+	int ret;
 
 	priv->reg = dev_remap_addr(dev);
 	if (!priv->reg)
 		return -EINVAL;
 
 	/*
-	 * Save core poke register address in reg (its not 0xa0000 as
-	 * extracted from the DT but 0x50000 instead)
+	 * Save base register address in reg masking lower 20 bits
+	 * as 0xa0000 appears when extracted from the DT
 	 */
 	priv->reg = (void __iomem *)(((u64)priv->reg &
-				      ~CORE0_POKE_OFFSET_MASK) |
-				     CORE0_POKE_OFFSET);
+				      ~CORE0_POKE_OFFSET_MASK));
+
+	ret = clk_get_by_index(dev, 0, &priv->clk);
+	if (ret < 0)
+		return ret;
+
+	ret = clk_enable(&priv->clk);
+	if (ret)
+		return ret;
 
 	return 0;
 }
 
 static const struct wdt_ops octeontx_wdt_ops = {
 	.reset = octeontx_wdt_reset,
+	.start = octeontx_wdt_start,
+	.stop = octeontx_wdt_stop,
+	.expire_now = octeontx_wdt_expire_now,
 };
 
 static const struct udevice_id octeontx_wdt_ids[] = {
@@ -63,4 +139,6 @@ U_BOOT_DRIVER(wdt_octeontx) = {
 	.ops = &octeontx_wdt_ops,
 	.priv_auto_alloc_size = sizeof(struct octeontx_wdt),
 	.probe = octeontx_wdt_probe,
+	.remove = octeontx_wdt_remove,
+	.flags = DM_FLAG_OS_PREPARE,
 };
-- 
2.28.0