[PATCH v3 4/6] watchdog: cortina_wdt: add support for HW WDT on CAxxxx SoCs

[Alex Nemirovsky]

From: Jason Li <jason.li at cortina-access.com>

Add support for hardware watchdog timer on all Cortina Access
CAxxxx family of SoCs.

Reviewed-by: Daniel Schwierzeck <daniel.schwierzeck at gmail.com>
Reviewed-by: Stefan Roese <sr at denx.de>
Signed-off-by: Jason Li <jason.li at cortina-access.com>
Signed-off-by: Alex Nemirovsky <alex.nemirovsky at cortina-access.com>


---

Changes in v3: None
Changes in v2:
- Rename driver in DT namespace for consistency between all
  CA drivers.
- Remove blank line after SPDX identifier
- Remove authorship comment as it is already recorded within Git
  and is redundant
- Use setbits_32() for read-modify-write operation.

 drivers/watchdog/Kconfig       |   8 +++
 drivers/watchdog/Makefile      |   1 +
 drivers/watchdog/cortina_wdt.c | 138 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 147 insertions(+)
 create mode 100644 drivers/watchdog/cortina_wdt.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 8c16d69..2f7dedb 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -99,6 +99,14 @@ config WDT_CDNS
 	   Select this to enable Cadence watchdog timer, which can be found on some
 	   Xilinx Microzed Platform.
 
+config WDT_CORTINA
+	bool "Cortina Access CAxxxx watchdog timer support"
+	depends on WDT
+	help
+	  Cortina Access CAxxxx watchdog timer support.
+	  This driver support all CPU ISAs supported by Cortina
+          Access CAxxxx SoCs.
+
 config WDT_MPC8xx
 	bool "MPC8xx watchdog timer support"
 	depends on WDT && MPC8xx
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 955caef..87f92a4 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -20,6 +20,7 @@ obj-$(CONFIG_WDT_SANDBOX) += sandbox_wdt.o
 obj-$(CONFIG_WDT_ARMADA_37XX) += armada-37xx-wdt.o
 obj-$(CONFIG_WDT_ASPEED) += ast_wdt.o
 obj-$(CONFIG_WDT_BCM6345) += bcm6345_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_MPC8xx) += mpc8xx_wdt.o
diff --git a/drivers/watchdog/cortina_wdt.c b/drivers/watchdog/cortina_wdt.c
new file mode 100644
index 0000000..f6a0e70
--- /dev/null
+++ b/drivers/watchdog/cortina_wdt.c
@@ -0,0 +1,138 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2020 Cortina-Access
+ *
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <asm/io.h>
+#include <wdt.h>
+#include <linux/bitops.h>
+
+#define CA_WDT_CTRL		0x00
+#define CA_WDT_PS		0x04
+#define CA_WDT_DIV		0x08
+#define CA_WDT_LD		0x0C
+#define CA_WDT_LOADE		0x10
+#define CA_WDT_CNT		0x14
+#define CA_WDT_IE		0x18
+#define CA_WDT_INT		0x1C
+#define CA_WDT_STAT		0x20
+
+/* CA_WDT_CTRL */
+#define CTL_WDT_EN		BIT(0)
+#define CTL_WDT_RSTEN		BIT(1)
+#define CTL_WDT_CLK_SEL		BIT(2)
+/* CA_WDT_LOADE */
+#define WDT_UPD			BIT(0)
+#define WDT_UPD_PS		BIT(1)
+
+/* Global config */
+#define WDT_RESET_SUB		BIT(4)
+#define WDT_RESET_ALL_BLOCK	BIT(6)
+#define WDT_RESET_REMAP		BIT(7)
+#define WDT_EXT_RESET		BIT(8)
+#define WDT_RESET_DEFAULT	(WDT_EXT_RESET | WDT_RESET_REMAP | \
+				 WDT_RESET_ALL_BLOCK | WDT_RESET_SUB)
+
+struct ca_wdt_priv {
+	void __iomem *base;
+	void __iomem *global_config;
+};
+
+static void cortina_wdt_set_timeout(struct udevice *dev, u64 timeout_ms)
+{
+	struct ca_wdt_priv *priv = dev_get_priv(dev);
+
+	/* Prescale using millisecond unit */
+	writel(CORTINA_PER_IO_FREQ / 1000, priv->base + CA_WDT_PS);
+
+	/* Millisecond */
+	writel(1, priv->base + CA_WDT_DIV);
+
+	writel(timeout_ms, priv->base + CA_WDT_LD);
+	writel(WDT_UPD | WDT_UPD_PS, priv->base + CA_WDT_LOADE);
+}
+
+static int cortina_wdt_start(struct udevice *dev, u64 timeout, ulong flags)
+{
+	struct ca_wdt_priv *priv = dev_get_priv(dev);
+
+	cortina_wdt_set_timeout(dev, timeout);
+
+	/* WDT Reset option */
+	setbits_32(priv->global_config, WDT_RESET_DEFAULT);
+
+	/* Enable WDT */
+	setbits_32(priv->base, CTL_WDT_EN | CTL_WDT_RSTEN | CTL_WDT_CLK_SEL);
+
+	return 0;
+}
+
+static int cortina_wdt_stop(struct udevice *dev)
+{
+	struct ca_wdt_priv *priv = dev_get_priv(dev);
+
+	/* Disable WDT */
+	writel(0, priv->base);
+
+	return 0;
+}
+
+static int cortina_wdt_reset(struct udevice *dev)
+{
+	struct ca_wdt_priv *priv = dev_get_priv(dev);
+
+	/* Reload WDT counter */
+	writel(WDT_UPD, priv->base + CA_WDT_LOADE);
+
+	return 0;
+}
+
+static int cortina_wdt_expire_now(struct udevice *dev, ulong flags)
+{
+	/* Set 1ms timeout to reset system */
+	cortina_wdt_set_timeout(dev, 1);
+	hang();
+
+	return 0;
+}
+
+static int cortina_wdt_probe(struct udevice *dev)
+{
+	struct ca_wdt_priv *priv = dev_get_priv(dev);
+
+	priv->base = dev_remap_addr_index(dev, 0);
+	if (!priv->base)
+		return -ENOENT;
+
+	priv->global_config = dev_remap_addr_index(dev, 1);
+	if (!priv->global_config)
+		return -ENOENT;
+
+	/* Stop WDT */
+	cortina_wdt_stop(dev);
+
+	return 0;
+}
+
+static const struct wdt_ops cortina_wdt_ops = {
+	.start = cortina_wdt_start,
+	.reset = cortina_wdt_reset,
+	.stop = cortina_wdt_stop,
+	.expire_now = cortina_wdt_expire_now,
+};
+
+static const struct udevice_id cortina_wdt_ids[] = {
+	{.compatible = "cortina,ca-wdt"},
+	{}
+};
+
+U_BOOT_DRIVER(cortina_wdt) = {
+	.name = "cortina_wdt",
+	.id = UCLASS_WDT,
+	.probe = cortina_wdt_probe,
+	.of_match = cortina_wdt_ids,
+	.ops = &cortina_wdt_ops,
+};
-- 
2.7.4