--- /dev/null
+/*
+ * drivers/char/watchdog/max63xx_wdt.c
+ *
+ * Driver for max63{69,70,71,72,73,74} watchdog timers
+ *
+ * Copyright (C) 2009 Marc Zyngier <maz@misterjones.org>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ *
+ * This driver assumes the watchdog pins are memory mapped (as it is
+ * the case for the Arcom Zeus). Should it be connected over GPIOs or
+ * another interface, some abstraction will have to be introduced.
+ */
+
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/watchdog.h>
+#include <linux/bitops.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+
+#define DEFAULT_HEARTBEAT 60
+#define MAX_HEARTBEAT 60
+
+static unsigned int heartbeat = DEFAULT_HEARTBEAT;
+static bool nowayout = WATCHDOG_NOWAYOUT;
+
+/*
+ * Memory mapping: a single byte, 3 first lower bits to select bit 3
+ * to ping the watchdog.
+ */
+#define MAX6369_WDSET (7 << 0)
+#define MAX6369_WDI (1 << 3)
+
+static DEFINE_SPINLOCK(io_lock);
+
+static int nodelay;
+static void __iomem *wdt_base;
+
+/*
+ * The timeout values used are actually the absolute minimum the chip
+ * offers. Typical values on my board are slightly over twice as long
+ * (10s setting ends up with a 25s timeout), and can be up to 3 times
+ * the nominal setting (according to the datasheet). So please take
+ * these values with a grain of salt. Same goes for the initial delay
+ * "feature". Only max6373/74 have a few settings without this initial
+ * delay (selected with the "nodelay" parameter).
+ *
+ * I also decided to remove from the tables any timeout smaller than a
+ * second, as it looked completly overkill...
+ */
+
+/* Timeouts in second */
+struct max63xx_timeout {
+ u8 wdset;
+ u8 tdelay;
+ u8 twd;
+};
+
+static struct max63xx_timeout max6369_table[] = {
+ { 5, 1, 1 },
+ { 6, 10, 10 },
+ { 7, 60, 60 },
+ { },
+};
+
+static struct max63xx_timeout max6371_table[] = {
+ { 6, 60, 3 },
+ { 7, 60, 60 },
+ { },
+};
+
+static struct max63xx_timeout max6373_table[] = {
+ { 2, 60, 1 },
+ { 5, 0, 1 },
+ { 1, 3, 3 },
+ { 7, 60, 10 },
+ { 6, 0, 10 },
+ { },
+};
+
+static struct max63xx_timeout *current_timeout;
+
+static struct max63xx_timeout *
+max63xx_select_timeout(struct max63xx_timeout *table, int value)
+{
+ while (table->twd) {
+ if (value <= table->twd) {
+ if (nodelay && table->tdelay == 0)
+ return table;
+
+ if (!nodelay)
+ return table;
+ }
+
+ table++;
+ }
+
+ return NULL;
+}
+
+static int max63xx_wdt_ping(struct watchdog_device *wdd)
+{
+ u8 val;
+
+ spin_lock(&io_lock);
+
+ val = __raw_readb(wdt_base);
+
+ __raw_writeb(val | MAX6369_WDI, wdt_base);
+ __raw_writeb(val & ~MAX6369_WDI, wdt_base);
+
+ spin_unlock(&io_lock);
+ return 0;
+}
+
+static int max63xx_wdt_start(struct watchdog_device *wdd)
+{
+ struct max63xx_timeout *entry = watchdog_get_drvdata(wdd);
+ u8 val;
+
+ spin_lock(&io_lock);
+
+ val = __raw_readb(wdt_base);
+ val &= ~MAX6369_WDSET;
+ val |= entry->wdset;
+ __raw_writeb(val, wdt_base);
+
+ spin_unlock(&io_lock);
+
+ /* check for a edge triggered startup */
+ if (entry->tdelay == 0)
+ max63xx_wdt_ping(wdd);
+ return 0;
+}
+
+static int max63xx_wdt_stop(struct watchdog_device *wdd)
+{
+ u8 val;
+
+ spin_lock(&io_lock);
+
+ val = __raw_readb(wdt_base);
+ val &= ~MAX6369_WDSET;
+ val |= 3;
+ __raw_writeb(val, wdt_base);
+
+ spin_unlock(&io_lock);
+ return 0;
+}
+
+static const struct watchdog_info max63xx_wdt_info = {
+ .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
+ .identity = "max63xx Watchdog",
+};
+
+static const struct watchdog_ops max63xx_wdt_ops = {
+ .owner = THIS_MODULE,
+ .start = max63xx_wdt_start,
+ .stop = max63xx_wdt_stop,
+ .ping = max63xx_wdt_ping,
+};
+
+static struct watchdog_device max63xx_wdt_dev = {
+ .info = &max63xx_wdt_info,
+ .ops = &max63xx_wdt_ops,
+};
+
+static int max63xx_wdt_probe(struct platform_device *pdev)
+{
+ struct resource *wdt_mem;
+ struct max63xx_timeout *table;
+
+ table = (struct max63xx_timeout *)pdev->id_entry->driver_data;
+
+ if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT)
+ heartbeat = DEFAULT_HEARTBEAT;
+
+ dev_info(&pdev->dev, "requesting %ds heartbeat\n", heartbeat);
+ current_timeout = max63xx_select_timeout(table, heartbeat);
+
+ if (!current_timeout) {
+ dev_err(&pdev->dev, "unable to satisfy heartbeat request\n");
+ return -EINVAL;
+ }
+
+ dev_info(&pdev->dev, "using %ds heartbeat with %ds initial delay\n",
+ current_timeout->twd, current_timeout->tdelay);
+
+ heartbeat = current_timeout->twd;
+
+ wdt_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ wdt_base = devm_ioremap_resource(&pdev->dev, wdt_mem);
+ if (IS_ERR(wdt_base))
+ return PTR_ERR(wdt_base);
+
+ max63xx_wdt_dev.timeout = heartbeat;
+ watchdog_set_nowayout(&max63xx_wdt_dev, nowayout);
+ watchdog_set_drvdata(&max63xx_wdt_dev, current_timeout);
+
+ return watchdog_register_device(&max63xx_wdt_dev);
+}
+
+static int max63xx_wdt_remove(struct platform_device *pdev)
+{
+ watchdog_unregister_device(&max63xx_wdt_dev);
+ return 0;
+}
+
+static struct platform_device_id max63xx_id_table[] = {
+ { "max6369_wdt", (kernel_ulong_t)max6369_table, },
+ { "max6370_wdt", (kernel_ulong_t)max6369_table, },
+ { "max6371_wdt", (kernel_ulong_t)max6371_table, },
+ { "max6372_wdt", (kernel_ulong_t)max6371_table, },
+ { "max6373_wdt", (kernel_ulong_t)max6373_table, },
+ { "max6374_wdt", (kernel_ulong_t)max6373_table, },
+ { },
+};
+MODULE_DEVICE_TABLE(platform, max63xx_id_table);
+
+static struct platform_driver max63xx_wdt_driver = {
+ .probe = max63xx_wdt_probe,
+ .remove = max63xx_wdt_remove,
+ .id_table = max63xx_id_table,
+ .driver = {
+ .name = "max63xx_wdt",
+ },
+};
+
+module_platform_driver(max63xx_wdt_driver);
+
+MODULE_AUTHOR("Marc Zyngier <maz@misterjones.org>");
+MODULE_DESCRIPTION("max63xx Watchdog Driver");
+
+module_param(heartbeat, int, 0);
+MODULE_PARM_DESC(heartbeat,
+ "Watchdog heartbeat period in seconds from 1 to "
+ __MODULE_STRING(MAX_HEARTBEAT) ", default "
+ __MODULE_STRING(DEFAULT_HEARTBEAT));
+
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
+ __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+module_param(nodelay, int, 0);
+MODULE_PARM_DESC(nodelay,
+ "Force selection of a timeout setting without initial delay "
+ "(max6373/74 only, default=0)");
+
+MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff