[PATCH v8 4/5] watchdog: Add RAVE SP watchdog driver

[Andrey Smirnov]

This driver provides access to RAVE SP watchdog functionality.

Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: linux-watchdog@xxxxxxxxxxxxxxx
Cc: cphealy@xxxxxxxxx
Cc: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
Cc: Nikita Yushchenko <nikita.yoush@xxxxxxxxxxxxxxxxxx>
Cc: Lee Jones <lee.jones@xxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Pavel Machek <pavel@xxxxxx>
Cc: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
Cc: Rob Herring <robh@xxxxxxxxxx>
Cc: Johan Hovold <johan@xxxxxxxxxx>
Signed-off-by: Nikita Yushchenko <nikita.yoush@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrey Smirnov <andrew.smirnov@xxxxxxxxx>
---
 drivers/watchdog/Kconfig       |   7 +
 drivers/watchdog/Makefile      |   1 +
 drivers/watchdog/rave-sp-wdt.c | 310 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 318 insertions(+)
 create mode 100644 drivers/watchdog/rave-sp-wdt.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index c722cbfdc7e6..533a72248cd1 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -223,6 +223,13 @@ config ZIIRAVE_WATCHDOG
 	  To compile this driver as a module, choose M here: the
 	  module will be called ziirave_wdt.
 
+config RAVE_SP_WATCHDOG
+	tristate "RAVE SP Watchdog timer"
+	depends on RAVE_SP_CORE
+	select WATCHDOG_CORE
+	help
+	  Support for the watchdog on RAVE SP device.
+
 # ALPHA Architecture
 
 # ARM Architecture
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 56adf9fa67d0..5c9556c09f6e 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -223,3 +223,4 @@ obj-$(CONFIG_MAX77620_WATCHDOG) += max77620_wdt.o
 obj-$(CONFIG_ZIIRAVE_WATCHDOG) += ziirave_wdt.o
 obj-$(CONFIG_SOFT_WATCHDOG) += softdog.o
 obj-$(CONFIG_MENF21BMC_WATCHDOG) += menf21bmc_wdt.o
+obj-$(CONFIG_RAVE_SP_WATCHDOG) += rave-sp-wdt.o
diff --git a/drivers/watchdog/rave-sp-wdt.c b/drivers/watchdog/rave-sp-wdt.c
new file mode 100644
index 000000000000..86fdc7fb1f92
--- /dev/null
+++ b/drivers/watchdog/rave-sp-wdt.c
@@ -0,0 +1,310 @@
+/*
+ *  rave-sp-wdt.c - Watchdog driver preseing in RAVE SP
+ *
+ * Copyright (C) 2017 Zodiac Inflight Innovation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/rave-sp.h>
+#include <linux/watchdog.h>
+#include <linux/nvmem-consumer.h>
+#include <linux/reboot.h>
+#include <linux/slab.h>
+
+enum {
+	RAVE_SP_RESET_BYTE = 1,
+	RAVE_SP_RESET_REASON_NORMAL = 0,
+	RAVE_SP_RESET_DELAY_MS = 500,
+};
+
+struct rave_sp_wdt_variant {
+	unsigned int max_timeout;
+	unsigned int min_timeout;
+
+	int (*configure)(struct watchdog_device *);
+	int (*restart)(struct watchdog_device *);
+};
+
+struct rave_sp_wdt {
+	struct watchdog_device wdd;
+	struct rave_sp *sp;
+	const struct rave_sp_wdt_variant *variant;
+	struct notifier_block reboot_notifier;
+};
+
+static struct rave_sp_wdt *to_rave_sp_wdt(struct watchdog_device *wdd)
+{
+	return container_of(wdd, struct rave_sp_wdt, wdd);
+}
+
+static int __rave_sp_wdt_exec(struct watchdog_device *wdd,
+			      void *data,  size_t data_size,
+			      void *reply, size_t reply_size)
+{
+	return rave_sp_exec(to_rave_sp_wdt(wdd)->sp,
+			    data, data_size, reply, reply_size);
+}
+
+static int rave_sp_wdt_exec(struct watchdog_device *wdd, void *data,
+			    size_t data_size)
+{
+	return __rave_sp_wdt_exec(wdd, data, data_size, NULL, 0);
+}
+
+
+static int rave_sp_wdt_legacy_configure(struct watchdog_device *wdd)
+{
+	const bool enable = watchdog_hw_running(wdd);
+	u8 cmd[] = {
+		[0] = RAVE_SP_CMD_SW_WDT,
+		[1] = 0,
+		[2] = 0,
+		[3] = !!enable,
+		[4] = enable ? wdd->timeout : 0,
+	};
+	return rave_sp_wdt_exec(wdd, cmd, sizeof(cmd));
+}
+
+static int rave_sp_wdt_rdu_configure(struct watchdog_device *wdd)
+{
+	u8 cmd[] = {
+		[0] = RAVE_SP_CMD_SW_WDT,
+		[1] = 0,
+		[2] = watchdog_hw_running(wdd),
+		[3] = (u8) wdd->timeout,
+		[4] = (u8) (wdd->timeout >> 8),
+	};
+	return rave_sp_wdt_exec(wdd, cmd, sizeof(cmd));
+}
+
+static int rave_sp_wdt_configure(struct watchdog_device *wdd)
+{
+	return to_rave_sp_wdt(wdd)->variant->configure(wdd);
+}
+
+static int rave_sp_wdt_legacy_restart(struct watchdog_device *wdd)
+{
+	u8 cmd[] = {
+		[0] = RAVE_SP_CMD_RESET,
+		[1] = 0,
+		[2] = RAVE_SP_RESET_BYTE
+	};
+	return rave_sp_wdt_exec(wdd, cmd, sizeof(cmd));
+}
+
+static int rave_sp_wdt_rdu_restart(struct watchdog_device *wdd)
+{
+	u8 cmd[] = {
+		[0] = RAVE_SP_CMD_RESET,
+		[1] = 0,
+		[2] = RAVE_SP_RESET_BYTE,
+		[3] = RAVE_SP_RESET_REASON_NORMAL
+	};
+	return rave_sp_wdt_exec(wdd, cmd, sizeof(cmd));
+}
+
+static int rave_sp_wdt_reboot_notifier(struct notifier_block *nb,
+				       unsigned long action, void *data)
+{
+	/*
+	 * Restart handler is called in atomic context which means we
+	 * can't commuicate to SP via UART. Luckily for use SP will
+	 * wait 500ms before actually resetting us, so we ask it to do
+	 * so here and let the rest of the system go on wrapping
+	 * things up.
+	 */
+	if (action == SYS_DOWN || action == SYS_HALT) {
+		struct rave_sp_wdt *sp_wd =
+			container_of(nb, struct rave_sp_wdt, reboot_notifier);
+
+		const int ret = sp_wd->variant->restart(&sp_wd->wdd);
+
+		if (ret < 0)
+			dev_err(sp_wd->wdd.parent,
+				"Failed to issue restart command (%d)", ret);
+		return NOTIFY_OK;
+	}
+
+	return NOTIFY_DONE;
+}
+
+static int rave_sp_wdt_restart(struct watchdog_device *wdd,
+			       unsigned long action, void *data)
+{
+	/*
+	 * The actual work was done by reboot notifier above. SP
+	 * firmware waits 500 ms before issuing reset, so let's hang
+	 * here for one second and hopefuly we'd never reach that
+	 * return statement
+	 */
+	mdelay(RAVE_SP_RESET_DELAY_MS);
+	return -EIO;
+}
+
+static int rave_sp_wdt_start(struct watchdog_device *wdd)
+{
+	set_bit(WDOG_HW_RUNNING, &wdd->status);
+	return rave_sp_wdt_configure(wdd);
+}
+
+static int rave_sp_wdt_set_timeout(struct watchdog_device *wdd,
+				   unsigned int timeout)
+{
+	wdd->timeout = timeout;
+	return rave_sp_wdt_configure(wdd);
+}
+
+static int rave_sp_wdt_ping(struct watchdog_device *wdd)
+{
+	u8 cmd[] = {
+		[0] = RAVE_SP_CMD_PET_WDT,
+		[1] = 0,
+	};
+
+	return rave_sp_wdt_exec(wdd, cmd, sizeof(cmd));
+}
+
+static const struct watchdog_info rave_sp_wdt_info = {
+	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
+	.identity = "RAVE SP Watchdog",
+};
+
+static const struct watchdog_ops rave_sp_wdt_ops = {
+	.owner = THIS_MODULE,
+	.start = rave_sp_wdt_start,
+	.stop = rave_sp_wdt_configure,
+	.ping = rave_sp_wdt_ping,
+	.set_timeout = rave_sp_wdt_set_timeout,
+	.restart = rave_sp_wdt_restart,
+};
+
+static const struct of_device_id rave_sp_wdt_of_match[] = {
+	{ .compatible = "zii,rave-sp-watchdog" },
+	{}
+};
+
+static const struct rave_sp_wdt_variant rave_sp_wdt_legacy = {
+	.max_timeout = 255,
+	.min_timeout = 1,
+	.configure = rave_sp_wdt_legacy_configure,
+	.restart   = rave_sp_wdt_legacy_restart,
+};
+
+static const struct rave_sp_wdt_variant rave_sp_wdt_rdu = {
+	.max_timeout = 180,
+	.min_timeout = 60,
+	.configure = rave_sp_wdt_rdu_configure,
+	.restart   = rave_sp_wdt_rdu_restart,
+};
+
+static const struct of_device_id rave_sp_wdt_variants[] = {
+	{ .compatible = COMPATIBLE_RAVE_SP_NIU,  .data = &rave_sp_wdt_legacy },
+	{ .compatible = COMPATIBLE_RAVE_SP_MEZZ, .data = &rave_sp_wdt_legacy },
+	{ .compatible = COMPATIBLE_RAVE_SP_ESB,  .data = &rave_sp_wdt_legacy },
+	{ .compatible = COMPATIBLE_RAVE_SP_RDU1, .data = &rave_sp_wdt_rdu    },
+	{ .compatible = COMPATIBLE_RAVE_SP_RDU2, .data = &rave_sp_wdt_rdu    },
+	{ /* sentinel */ }
+};
+
+static int rave_sp_wdt_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	const struct of_device_id *id;
+	struct watchdog_device *wdd;
+	struct rave_sp_wdt *sp_wd;
+	struct nvmem_cell *cell;
+	__le16 timeout = 0;
+	int ret;
+
+	id = of_match_device(rave_sp_wdt_variants, dev->parent);
+	if (WARN_ON(!id))
+		return -ENODEV;
+
+	sp_wd = devm_kzalloc(dev, sizeof(*sp_wd), GFP_KERNEL);
+	if (!sp_wd)
+		return -ENOMEM;
+
+	sp_wd->variant = id->data;
+	sp_wd->sp      = dev_get_drvdata(dev->parent);
+
+	if (WARN_ON(!sp_wd->sp))
+		return -ENODEV;
+
+	wdd              = &sp_wd->wdd;
+	wdd->parent      = dev;
+	wdd->info        = &rave_sp_wdt_info;
+	wdd->ops         = &rave_sp_wdt_ops;
+	wdd->min_timeout = sp_wd->variant->min_timeout;
+	wdd->max_timeout = sp_wd->variant->max_timeout;
+	wdd->status      = WATCHDOG_NOWAYOUT_INIT_STATUS;
+	wdd->timeout     = 60;
+
+	cell = nvmem_cell_get(dev, "wdt_timeout");
+	if (!IS_ERR(cell)) {
+		size_t len;
+		void *value = nvmem_cell_read(cell, &len);
+
+		if (!IS_ERR(value)) {
+			memcpy(&timeout, value, min(len, sizeof(timeout)));
+			kfree(value);
+		}
+		nvmem_cell_put(cell);
+	}
+	watchdog_init_timeout(wdd, le16_to_cpu(timeout), dev);
+	watchdog_set_restart_priority(wdd, 255);
+
+	sp_wd->reboot_notifier.notifier_call = rave_sp_wdt_reboot_notifier;
+	ret = devm_register_reboot_notifier(dev, &sp_wd->reboot_notifier);
+	if (ret) {
+		dev_err(dev, "Failed to register reboot notifier\n");
+		return ret;
+	}
+
+	/*
+	 * We don't know if watchdog is running now. To be sure, let's
+	 * start it and depend on watchdog core to ping it
+	 */
+	wdd->max_hw_heartbeat_ms = wdd->max_timeout * 1000;
+	ret = rave_sp_wdt_start(wdd);
+	if (ret) {
+		dev_err(dev, "Watchdog didn't start\n");
+		return ret;
+	}
+
+	return devm_watchdog_register_device(dev, wdd);
+}
+
+static struct platform_driver rave_sp_wdt_driver = {
+	.probe = rave_sp_wdt_probe,
+	.driver = {
+		.name = KBUILD_MODNAME,
+		.of_match_table = rave_sp_wdt_of_match,
+	},
+};
+
+module_platform_driver(rave_sp_wdt_driver);
+
+MODULE_DEVICE_TABLE(of, rave_sp_wdt_of_match);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Andrey Vostrikov <andrey.vostrikov@xxxxxxxxxxxxxxxxxx>");
+MODULE_AUTHOR("Nikita Yushchenko <nikita.yoush@xxxxxxxxxxxxxxxxxx>");
+MODULE_AUTHOR("Andrey Smirnov <andrew.smirnov@xxxxxxxxx>");
+MODULE_DESCRIPTION("RAVE SP Watchdog driver");
+MODULE_ALIAS("platform:rave-sp-watchdog");
-- 
2.13.5