[2/2,v6] Watchdog: Add marvell GTI watchdog driver

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index f0872970daf9..bb8241e60d33 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -1779,6 +1779,19 @@  config OCTEON_WDT
 	  from the first interrupt, it is then only poked when the
 	  device is written.
 
+config MARVELL_GTI_WDT
+	tristate "Marvell GTI Watchdog driver"
+	depends on ARCH_THUNDER || COMPILE_TEST
+	default y
+	select WATCHDOG_CORE
+	help
+	 Marvell GTI hardware supports watchdog timer. First timeout
+	 works as watchdog pretimeout and installed interrupt handler
+	 will be called on first timeout. Hardware can generate interrupt
+	 to SCP on second timeout but it is not enabled, So second
+	 timeout is ignored. If device poke does not happen then system
+	 will reboot on third timeout.
+
 config BCM2835_WDT
 	tristate "Broadcom BCM2835 hardware watchdog"
 	depends on ARCH_BCM2835 || (OF && COMPILE_TEST)
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 9cbf6580f16c..bd425408fcaa 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -98,6 +98,7 @@  obj-$(CONFIG_VISCONTI_WATCHDOG) += visconti_wdt.o
 obj-$(CONFIG_MSC313E_WATCHDOG) += msc313e_wdt.o
 obj-$(CONFIG_APPLE_WATCHDOG) += apple_wdt.o
 obj-$(CONFIG_SUNPLUS_WATCHDOG) += sunplus_wdt.o
+obj-$(CONFIG_MARVELL_GTI_WDT) += marvell_gti_wdt.o
 
 # X86 (i386 + ia64 + x86_64) Architecture
 obj-$(CONFIG_ACQUIRE_WDT) += acquirewdt.o
diff --git a/drivers/watchdog/marvell_gti_wdt.c b/drivers/watchdog/marvell_gti_wdt.c
new file mode 100644
index 000000000000..aa2e9bca9c88
--- /dev/null
+++ b/drivers/watchdog/marvell_gti_wdt.c
@@ -0,0 +1,327 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/* Marvell GTI Watchdog driver
+ *
+ * Copyright (C) 2023 Marvell.
+ */
+
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/watchdog.h>
+#include <linux/clk.h>
+
+/*
+ * Hardware supports following mode of operation:
+ * 1) Interrupt Only:
+ *    This will generate the interrupt to arm core whenever timeout happens.
+ *
+ * 2) Interrupt + del3t (Interrupt to firmware (SCP processor)).
+ *    This will generate interrupt to arm core on 1st timeout happens
+ *    This will generate interrupt to SCP processor on 2nd timeout happens
+ *
+ * 3) Interrupt + Interrupt to SCP processor (called delt3t) + reboot.
+ *    This will generate interrupt to arm core on 1st timeout happens
+ *    Will generate interrupt to SCP processor on 2nd timeout happens,
+ *    if interrupt is configured.
+ *    Reboot on 3rd timeout.
+ *
+ * Driver will use hardware in mode-3 above so that system can reboot in case
+ * a hardware hang. Also h/w is configured not to generate SCP interrupt, so
+ * effectively 2nd timeout is ignored within hardware.
+ *
+ * First timeout is effectively watchdog pretimeout.
+ */
+
+/* GTI CWD Watchdog (GTI_CWD_WDOG) Register */
+#define GTI_CWD_WDOG(reg_offset)	(0x8 * reg_offset)
+#define GTI_CWD_WDOG_MODE_INT_DEL3T_RST	0x3
+#define GTI_CWD_WDOG_MODE_MASK		GENMASK_ULL(1, 0)
+#define GTI_CWD_WDOG_LEN_SHIFT		4
+#define GTI_CWD_WDOG_LEN_MASK		GENMASK_ULL(19, 4)
+#define GTI_CWD_WDOG_CNT_SHIFT		20
+#define GTI_CWD_WDOG_CNT_MASK		GENMASK_ULL(43, 20)
+
+/* GTI CWD Watchdog Interrupt (GTI_CWD_INT) Register */
+#define GTI_CWD_INT			0x200
+#define GTI_CWD_INT_PENDING_STATUS(bit)	(1 << bit)
+
+/* GTI CWD Watchdog Interrupt Enable Clear (GTI_CWD_INT_ENA_CLR) Register */
+#define GTI_CWD_INT_ENA_CLR		0x210
+#define GTI_CWD_INT_ENA_CLR_VAL(bit)	(1 << bit)
+
+/* GTI CWD Watchdog Interrupt Enable Set (GTI_CWD_INT_ENA_SET) Register */
+#define GTI_CWD_INT_ENA_SET		0x218
+#define GTI_CWD_INT_ENA_SET_VAL(bit)	(1 << bit)
+
+/* GTI CWD Watchdog Poke (GTI_CWD_POKE) Registers */
+#define GTI_CWD_POKE(reg_offset)	(0x10000 + 0x8 * reg_offset)
+#define GTI_CWD_POKE_VAL		1
+
+struct gti_wdt_priv {
+	struct watchdog_device wdev;
+	void __iomem *base;
+	u32 clock_freq;
+	struct clk *sclk;
+	/*
+	 * GTI hardware block supports total 64 timers, wdt_timer_idx
+	 * used for timer to be used for system watchdog.
+	 */
+	u32 wdt_timer_idx;
+};
+
+static irqreturn_t gti_wdt_interrupt(int irq, void *data)
+{
+	struct watchdog_device *wdev = data;
+	struct gti_wdt_priv *priv = watchdog_get_drvdata(wdev);
+
+	/* Clear Interrupt Pending Status */
+	writeq(GTI_CWD_INT_PENDING_STATUS(priv->wdt_timer_idx),
+	       priv->base + GTI_CWD_INT);
+
+	watchdog_notify_pretimeout(wdev);
+
+	return IRQ_HANDLED;
+}
+
+static int gti_wdt_ping(struct watchdog_device *wdev)
+{
+	struct gti_wdt_priv *priv = watchdog_get_drvdata(wdev);
+
+	writeq(GTI_CWD_POKE_VAL,
+	       priv->base + GTI_CWD_POKE(priv->wdt_timer_idx));
+
+	return 0;
+}
+
+static int gti_wdt_start(struct watchdog_device *wdev)
+{
+	struct gti_wdt_priv *priv = watchdog_get_drvdata(wdev);
+	u64 regval;
+
+	if (!wdev->pretimeout)
+		return -EINVAL;
+
+	set_bit(WDOG_HW_RUNNING, &wdev->status);
+
+	/* Clear any pending interrupt */
+	writeq(GTI_CWD_INT_PENDING_STATUS(priv->wdt_timer_idx),
+	       priv->base + GTI_CWD_INT);
+
+	/* Enable Interrupt */
+	writeq(GTI_CWD_INT_ENA_SET_VAL(priv->wdt_timer_idx),
+	       priv->base + GTI_CWD_INT_ENA_SET);
+
+	/* Set (Interrupt + SCP interrupt (DEL3T) + core domain reset) Mode */
+	regval = readq(priv->base + GTI_CWD_WDOG(priv->wdt_timer_idx));
+	regval |= GTI_CWD_WDOG_MODE_INT_DEL3T_RST;
+	writeq(regval, priv->base + GTI_CWD_WDOG(priv->wdt_timer_idx));
+
+	return 0;
+}
+
+static int gti_wdt_stop(struct watchdog_device *wdev)
+{
+	struct gti_wdt_priv *priv = watchdog_get_drvdata(wdev);
+	u64 regval;
+
+	/* Disable Interrupt */
+	writeq(GTI_CWD_INT_ENA_CLR_VAL(priv->wdt_timer_idx),
+	       priv->base + GTI_CWD_INT_ENA_CLR);
+
+	/* Set GTI_CWD_WDOG.Mode = 0 to stop the timer */
+	regval = readq(priv->base + GTI_CWD_WDOG(priv->wdt_timer_idx));
+	regval &= ~GTI_CWD_WDOG_MODE_MASK;
+	writeq(regval, priv->base + GTI_CWD_WDOG(priv->wdt_timer_idx));
+
+	return 0;
+}
+
+static int gti_wdt_settimeout(struct watchdog_device *wdev,
+					unsigned int timeout)
+{
+	struct gti_wdt_priv *priv = watchdog_get_drvdata(wdev);
+	u64 timeout_wdog, regval;
+
+	/* Update new timeout */
+	wdev->timeout = timeout;
+
+	/* Pretimeout is 1/3 of timeout */
+	wdev->pretimeout = timeout / 3;
+
+	/* Get clock cycles from pretimeout */
+	timeout_wdog = (u64)priv->clock_freq * wdev->pretimeout;
+
+	/* Watchdog counts in 1024 cycle steps */
+	timeout_wdog = timeout_wdog >> 10;
+
+	/* GTI_CWD_WDOG.CNT: reload counter is 16-bit */
+	timeout_wdog = (timeout_wdog + 0xff) >> 8;
+	if (timeout_wdog >= 0x10000)
+		timeout_wdog = 0xffff;
+
+	/*
+	 * GTI_CWD_WDOG.LEN is 24bit, lower 8-bits should be zero and
+	 * upper 16-bits are same as GTI_CWD_WDOG.CNT
+	 */
+	regval = readq(priv->base + GTI_CWD_WDOG(priv->wdt_timer_idx));
+	regval &= GTI_CWD_WDOG_MODE_MASK;
+	regval |= (timeout_wdog << (GTI_CWD_WDOG_CNT_SHIFT + 8)) |
+		   (timeout_wdog << GTI_CWD_WDOG_LEN_SHIFT);
+	writeq(regval, priv->base + GTI_CWD_WDOG(priv->wdt_timer_idx));
+
+	return 0;
+}
+
+static int gti_wdt_set_pretimeout(struct watchdog_device *wdev,
+					unsigned int timeout)
+{
+	struct gti_wdt_priv *priv = watchdog_get_drvdata(wdev);
+	struct watchdog_device *wdog_dev = &priv->wdev;
+
+	/* pretimeout should 1/3 of max_timeout */
+	if (timeout * 3 <= wdog_dev->max_timeout)
+		return gti_wdt_settimeout(wdev, timeout * 3);
+
+	return -EINVAL;
+}
+
+static void gti_clk_disable_unprepare(void *data)
+{
+	clk_disable_unprepare(data);
+}
+
+static int gti_wdt_get_cntfrq(struct platform_device *pdev,
+			      struct gti_wdt_priv *priv)
+{
+	int err;
+
+	priv->sclk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(priv->sclk))
+		return PTR_ERR(priv->sclk);
+
+	err = clk_prepare_enable(priv->sclk);
+	if (err)
+		return err;
+
+	err = devm_add_action_or_reset(&pdev->dev,
+				       gti_clk_disable_unprepare, priv->sclk);
+	if (err)
+		return err;
+
+	priv->clock_freq = clk_get_rate(priv->sclk);
+	if (!priv->clock_freq)
+		return -EINVAL;
+
+	return 0;
+}
+
+static const struct watchdog_info gti_wdt_ident = {
+	.identity = "Marvell GTI watchdog",
+	.options = WDIOF_SETTIMEOUT | WDIOF_PRETIMEOUT | WDIOF_KEEPALIVEPING |
+		   WDIOF_MAGICCLOSE | WDIOF_CARDRESET,
+};
+
+static const struct watchdog_ops gti_wdt_ops = {
+	.owner = THIS_MODULE,
+	.start = gti_wdt_start,
+	.stop = gti_wdt_stop,
+	.ping = gti_wdt_ping,
+	.set_timeout = gti_wdt_settimeout,
+	.set_pretimeout = gti_wdt_set_pretimeout,
+};
+
+static int gti_wdt_probe(struct platform_device *pdev)
+{
+	struct gti_wdt_priv *priv;
+	struct device *dev = &pdev->dev;
+	struct watchdog_device *wdog_dev;
+	u64 max_pretimeout;
+	u32 wdt_idx;
+	int irq;
+	int err;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(priv->base))
+		return dev_err_probe(&pdev->dev, PTR_ERR(priv->base),
+			      "reg property not valid/found\n");
+
+	err = gti_wdt_get_cntfrq(pdev, priv);
+	if (err)
+		return dev_err_probe(&pdev->dev, err,
+				     "GTI clock frequency not valid/found");
+
+	/*
+	 * GTI hardware block supports total 64 timers, "wdt-timer-index"
+	 * property used for timer to be used for system watchdog.
+	 */
+	err = of_property_read_u32(dev->of_node, "marvell,wdt-timer-index",
+				   &wdt_idx);
+	if (err || wdt_idx > 63)
+		return dev_err_probe(&pdev->dev, err,
+				     "GTI wdog timer index not valid/found");
+
+	priv->wdt_timer_idx = wdt_idx;
+	wdog_dev = &priv->wdev;
+	wdog_dev->info = &gti_wdt_ident,
+	wdog_dev->ops = &gti_wdt_ops,
+	wdog_dev->parent = dev;
+	/*
+	 * Watchdog counter is 24 bit where lower 8 bits are zeros
+	 * This counter decrements every 1024 clock cycles.
+	 */
+	max_pretimeout = (GTI_CWD_WDOG_CNT_MASK >> GTI_CWD_WDOG_CNT_SHIFT);
+	max_pretimeout &= ~0xFFUL;
+	max_pretimeout = (max_pretimeout * 1024) / priv->clock_freq;
+	wdog_dev->pretimeout = max_pretimeout;
+
+	/* Maximum timeout is 3 times the pretimeout */
+	wdog_dev->max_timeout = max_pretimeout * 3;
+	/* Minimum first timeout (pretimeout) is 1, so min_timeout as 3 */
+	wdog_dev->min_timeout = 3;
+	wdog_dev->timeout = wdog_dev->pretimeout;
+
+	watchdog_set_drvdata(wdog_dev, priv);
+	platform_set_drvdata(pdev, priv);
+	gti_wdt_settimeout(wdog_dev, wdog_dev->timeout);
+	watchdog_stop_on_reboot(wdog_dev);
+	watchdog_stop_on_unregister(wdog_dev);
+
+	err = devm_watchdog_register_device(dev, wdog_dev);
+	if (err)
+		return err;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return dev_err_probe(&pdev->dev, irq, "IRQ resource not found\n");
+
+	err = devm_request_irq(dev, irq, gti_wdt_interrupt, 0,
+			       pdev->name, &priv->wdev);
+	if (err)
+		return dev_err_probe(dev, err, "Failed to register interrupt handler\n");
+
+	dev_info(dev, "Watchdog enabled (timeout=%d sec)\n", wdog_dev->timeout);
+	return 0;
+}
+
+static const struct of_device_id gti_wdt_of_match[] = {
+	{ .compatible = "marvell,gti-wdt", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, gti_wdt_of_match);
+
+static struct platform_driver gti_wdt_driver = {
+	.driver = {
+		.name = "gti-wdt",
+		.of_match_table = gti_wdt_of_match,
+	},
+	.probe = gti_wdt_probe,
+};
+module_platform_driver(gti_wdt_driver);
+
+MODULE_AUTHOR("Bharat Bhushan <bbhushan2@marvell.com>");
+MODULE_DESCRIPTION("Marvell GTI watchdog driver");