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Subject[PATCH v17 4/5] watchdog: Add RAVE SP watchdog driver
Date
This driver provides access to RAVE SP watchdog functionality.

Cc: linux-kernel@vger.kernel.org
Cc: linux-watchdog@vger.kernel.org
Cc: cphealy@gmail.com
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Rob Herring <robh@kernel.org>
Cc: Johan Hovold <johan@kernel.org>
Cc: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Acked-by: Philippe Ombredanne <pombredanne@nexb.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
---
drivers/watchdog/Kconfig | 7 +
drivers/watchdog/Makefile | 1 +
drivers/watchdog/rave-sp-wdt.c | 337 +++++++++++++++++++++++++++++++++++++++++
3 files changed, 345 insertions(+)
create mode 100644 drivers/watchdog/rave-sp-wdt.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index ca200d1f310a..5bf613d3b7d6 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 715a21078e0c..135c5e81f25e 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -224,3 +224,4 @@ 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..35db173252f9
--- /dev/null
+++ b/drivers/watchdog/rave-sp-wdt.c
@@ -0,0 +1,337 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+/*
+ * Driver for watchdog aspect of for Zodiac Inflight Innovations RAVE
+ * Supervisory Processor(SP) MCU
+ *
+ * Copyright (C) 2017 Zodiac Inflight Innovation
+ *
+ */
+
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/mfd/rave-sp.h>
+#include <linux/module.h>
+#include <linux/nvmem-consumer.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/reboot.h>
+#include <linux/slab.h>
+#include <linux/watchdog.h>
+
+enum {
+ RAVE_SP_RESET_BYTE = 1,
+ RAVE_SP_RESET_REASON_NORMAL = 0,
+ RAVE_SP_RESET_DELAY_MS = 500,
+};
+
+/**
+ * struct rave_sp_wdt_variant - RAVE SP watchdog variant
+ *
+ * @max_timeout: Largest possible watchdog timeout setting
+ * @min_timeout: Smallest possible watchdog timeout setting
+ *
+ * @configure: Function to send configuration command
+ * @restart: Function to send "restart" command
+ */
+struct rave_sp_wdt_variant {
+ unsigned int max_timeout;
+ unsigned int min_timeout;
+
+ int (*configure)(struct watchdog_device *, bool);
+ int (*restart)(struct watchdog_device *);
+};
+
+/**
+ * struct rave_sp_wdt - RAVE SP watchdog
+ *
+ * @wdd: Underlying watchdog device
+ * @sp: Pointer to parent RAVE SP device
+ * @variant: Device specific variant information
+ * @reboot_notifier: Reboot notifier implementing machine reset
+ */
+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)
+{
+ return rave_sp_exec(to_rave_sp_wdt(wdd)->sp,
+ data, data_size, NULL, 0);
+}
+
+static int rave_sp_wdt_legacy_configure(struct watchdog_device *wdd, bool on)
+{
+ u8 cmd[] = {
+ [0] = RAVE_SP_CMD_SW_WDT,
+ [1] = 0,
+ [2] = 0,
+ [3] = on,
+ [4] = on ? wdd->timeout : 0,
+ };
+
+ return rave_sp_wdt_exec(wdd, cmd, sizeof(cmd));
+}
+
+static int rave_sp_wdt_rdu_configure(struct watchdog_device *wdd, bool on)
+{
+ u8 cmd[] = {
+ [0] = RAVE_SP_CMD_SW_WDT,
+ [1] = 0,
+ [2] = on,
+ [3] = (u8)wdd->timeout,
+ [4] = (u8)(wdd->timeout >> 8),
+ };
+
+ return rave_sp_wdt_exec(wdd, cmd, sizeof(cmd));
+}
+
+/**
+ * rave_sp_wdt_configure - Configure watchdog device
+ *
+ * @wdd: Device to configure
+ * @on: Desired state of the watchdog timer (ON/OFF)
+ *
+ * This function configures two aspects of the watchdog timer:
+ *
+ * - Wheither it is ON or OFF
+ * - Its timeout duration
+ *
+ * with first aspect specified via function argument and second via
+ * the value of 'wdd->timeout'.
+ */
+static int rave_sp_wdt_configure(struct watchdog_device *wdd, bool on)
+{
+ return to_rave_sp_wdt(wdd)->variant->configure(wdd, on);
+}
+
+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 communicate 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 twice that delay and hopefuly we'd never reach
+ * the return statement.
+ */
+ mdelay(2 * RAVE_SP_RESET_DELAY_MS);
+
+ return -EIO;
+}
+
+static int rave_sp_wdt_start(struct watchdog_device *wdd)
+{
+ int ret;
+
+ ret = rave_sp_wdt_configure(wdd, true);
+ if (!ret)
+ set_bit(WDOG_HW_RUNNING, &wdd->status);
+
+ return ret;
+}
+
+static int rave_sp_wdt_stop(struct watchdog_device *wdd)
+{
+ return rave_sp_wdt_configure(wdd, false);
+}
+
+static int rave_sp_wdt_set_timeout(struct watchdog_device *wdd,
+ unsigned int timeout)
+{
+ wdd->timeout = timeout;
+
+ return rave_sp_wdt_configure(wdd, watchdog_active(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_stop,
+ .ping = rave_sp_wdt_ping,
+ .set_timeout = rave_sp_wdt_set_timeout,
+ .restart = rave_sp_wdt_restart,
+};
+
+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_of_match[] = {
+ {
+ .compatible = "zii,rave-sp-watchdog-legacy",
+ .data = &rave_sp_wdt_legacy,
+ },
+ {
+ .compatible = "zii,rave-sp-watchdog",
+ .data = &rave_sp_wdt_rdu,
+ },
+ { /* sentinel */ }
+};
+
+static int rave_sp_wdt_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct watchdog_device *wdd;
+ struct rave_sp_wdt *sp_wd;
+ struct nvmem_cell *cell;
+ __le16 timeout = 0;
+ int ret;
+
+ sp_wd = devm_kzalloc(dev, sizeof(*sp_wd), GFP_KERNEL);
+ if (!sp_wd)
+ return -ENOMEM;
+
+ sp_wd->variant = of_device_get_match_data(dev);
+ sp_wd->sp = dev_get_drvdata(dev->parent);
+
+ 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);
+ watchdog_stop_on_unregister(wdd);
+
+ 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;
+ }
+
+ ret = devm_watchdog_register_device(dev, wdd);
+ if (ret) {
+ dev_err(dev, "Failed to register watchdog device\n");
+ rave_sp_wdt_stop(wdd);
+ return ret;
+ }
+
+ return 0;
+}
+
+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@cogentembedded.com>");
+MODULE_AUTHOR("Nikita Yushchenko <nikita.yoush@cogentembedded.com>");
+MODULE_AUTHOR("Andrey Smirnov <andrew.smirnov@gmail.com>");
+MODULE_DESCRIPTION("RAVE SP Watchdog driver");
+MODULE_ALIAS("platform:rave-sp-watchdog");
--
2.14.3
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