watchdog: Kontron PLD watchdog timer driver
Add watchdog timer support for the on-board PLD found on some Kontron
embedded modules.
Originally-From: Michael Brunner <michael.brunner@kontron.com>
Signed-off-by: Kevin Strasser <kevin.strasser@linux.intel.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Darren Hart <dvhart@linux.intel.com>
Acked-by: Wim Van Sebroeck <wim@iguana.be>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/drivers/watchdog/kempld_wdt.c b/drivers/watchdog/kempld_wdt.c
new file mode 100644
index 0000000..491419e
--- /dev/null
+++ b/drivers/watchdog/kempld_wdt.c
@@ -0,0 +1,581 @@
+/*
+ * Kontron PLD watchdog driver
+ *
+ * Copyright (c) 2010-2013 Kontron Europe GmbH
+ * Author: Michael Brunner <michael.brunner@kontron.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License 2 as published
+ * by the Free Software Foundation.
+ *
+ * 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.
+ *
+ * Note: From the PLD watchdog point of view timeout and pretimeout are
+ * defined differently than in the kernel.
+ * First the pretimeout stage runs out before the timeout stage gets
+ * active.
+ *
+ * Kernel/API: P-----| pretimeout
+ * |-----------------------T timeout
+ * Watchdog: |-----------------P pretimeout_stage
+ * |-----T timeout_stage
+ */
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/miscdevice.h>
+#include <linux/uaccess.h>
+#include <linux/watchdog.h>
+#include <linux/platform_device.h>
+#include <linux/mfd/kempld.h>
+
+#define KEMPLD_WDT_STAGE_TIMEOUT(x) (0x1b + (x) * 4)
+#define KEMPLD_WDT_STAGE_CFG(x) (0x18 + (x))
+#define STAGE_CFG_GET_PRESCALER(x) (((x) & 0x30) >> 4)
+#define STAGE_CFG_SET_PRESCALER(x) (((x) & 0x30) << 4)
+#define STAGE_CFG_PRESCALER_MASK 0x30
+#define STAGE_CFG_ACTION_MASK 0x7
+#define STAGE_CFG_ASSERT (1 << 3)
+
+#define KEMPLD_WDT_MAX_STAGES 2
+#define KEMPLD_WDT_KICK 0x16
+#define KEMPLD_WDT_CFG 0x17
+#define KEMPLD_WDT_CFG_ENABLE 0x10
+#define KEMPLD_WDT_CFG_ENABLE_LOCK 0x8
+#define KEMPLD_WDT_CFG_GLOBAL_LOCK 0x80
+
+enum {
+ ACTION_NONE = 0,
+ ACTION_RESET,
+ ACTION_NMI,
+ ACTION_SMI,
+ ACTION_SCI,
+ ACTION_DELAY,
+};
+
+enum {
+ STAGE_TIMEOUT = 0,
+ STAGE_PRETIMEOUT,
+};
+
+enum {
+ PRESCALER_21 = 0,
+ PRESCALER_17,
+ PRESCALER_12,
+};
+
+const u32 kempld_prescaler[] = {
+ [PRESCALER_21] = (1 << 21) - 1,
+ [PRESCALER_17] = (1 << 17) - 1,
+ [PRESCALER_12] = (1 << 12) - 1,
+ 0,
+};
+
+struct kempld_wdt_stage {
+ unsigned int id;
+ u32 mask;
+};
+
+struct kempld_wdt_data {
+ struct kempld_device_data *pld;
+ struct watchdog_device wdd;
+ unsigned int pretimeout;
+ struct kempld_wdt_stage stage[KEMPLD_WDT_MAX_STAGES];
+#ifdef CONFIG_PM
+ u8 pm_status_store;
+#endif
+};
+
+#define DEFAULT_TIMEOUT 30 /* seconds */
+#define DEFAULT_PRETIMEOUT 0
+
+static unsigned int timeout = DEFAULT_TIMEOUT;
+module_param(timeout, uint, 0);
+MODULE_PARM_DESC(timeout,
+ "Watchdog timeout in seconds. (>=0, default="
+ __MODULE_STRING(DEFAULT_TIMEOUT) ")");
+
+static unsigned int pretimeout = DEFAULT_PRETIMEOUT;
+module_param(pretimeout, uint, 0);
+MODULE_PARM_DESC(pretimeout,
+ "Watchdog pretimeout in seconds. (>=0, default="
+ __MODULE_STRING(DEFAULT_PRETIMEOUT) ")");
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout,
+ "Watchdog cannot be stopped once started (default="
+ __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+static int kempld_wdt_set_stage_action(struct kempld_wdt_data *wdt_data,
+ struct kempld_wdt_stage *stage,
+ u8 action)
+{
+ struct kempld_device_data *pld = wdt_data->pld;
+ u8 stage_cfg;
+
+ if (!stage || !stage->mask)
+ return -EINVAL;
+
+ kempld_get_mutex(pld);
+ stage_cfg = kempld_read8(pld, KEMPLD_WDT_STAGE_CFG(stage->id));
+ stage_cfg &= ~STAGE_CFG_ACTION_MASK;
+ stage_cfg |= (action & STAGE_CFG_ACTION_MASK);
+
+ if (action == ACTION_RESET)
+ stage_cfg |= STAGE_CFG_ASSERT;
+ else
+ stage_cfg &= ~STAGE_CFG_ASSERT;
+
+ kempld_write8(pld, KEMPLD_WDT_STAGE_CFG(stage->id), stage_cfg);
+ kempld_release_mutex(pld);
+
+ return 0;
+}
+
+static int kempld_wdt_set_stage_timeout(struct kempld_wdt_data *wdt_data,
+ struct kempld_wdt_stage *stage,
+ unsigned int timeout)
+{
+ struct kempld_device_data *pld = wdt_data->pld;
+ u32 prescaler = kempld_prescaler[PRESCALER_21];
+ u64 stage_timeout64;
+ u32 stage_timeout;
+ u32 remainder;
+ u8 stage_cfg;
+
+ if (!stage)
+ return -EINVAL;
+
+ stage_timeout64 = (u64)timeout * pld->pld_clock;
+ remainder = do_div(stage_timeout64, prescaler);
+ if (remainder)
+ stage_timeout64++;
+
+ if (stage_timeout64 > stage->mask)
+ return -EINVAL;
+
+ stage_timeout = stage_timeout64 & stage->mask;
+
+ kempld_get_mutex(pld);
+ stage_cfg = kempld_read8(pld, KEMPLD_WDT_STAGE_CFG(stage->id));
+ stage_cfg &= ~STAGE_CFG_PRESCALER_MASK;
+ stage_cfg |= STAGE_CFG_SET_PRESCALER(prescaler);
+ kempld_write8(pld, KEMPLD_WDT_STAGE_CFG(stage->id), stage_cfg);
+ kempld_write32(pld, KEMPLD_WDT_STAGE_TIMEOUT(stage->id),
+ stage_timeout);
+ kempld_release_mutex(pld);
+
+ return 0;
+}
+
+/*
+ * kempld_get_mutex must be called prior to calling this function.
+ */
+static unsigned int kempld_wdt_get_timeout(struct kempld_wdt_data *wdt_data,
+ struct kempld_wdt_stage *stage)
+{
+ struct kempld_device_data *pld = wdt_data->pld;
+ unsigned int timeout;
+ u64 stage_timeout;
+ u32 prescaler;
+ u32 remainder;
+ u8 stage_cfg;
+
+ if (!stage->mask)
+ return 0;
+
+ stage_cfg = kempld_read8(pld, KEMPLD_WDT_STAGE_CFG(stage->id));
+ stage_timeout = kempld_read32(pld, KEMPLD_WDT_STAGE_TIMEOUT(stage->id));
+ prescaler = kempld_prescaler[STAGE_CFG_GET_PRESCALER(stage_cfg)];
+
+ stage_timeout = (stage_timeout & stage->mask) * prescaler;
+ remainder = do_div(stage_timeout, pld->pld_clock);
+ if (remainder)
+ stage_timeout++;
+
+ timeout = stage_timeout;
+ WARN_ON_ONCE(timeout != stage_timeout);
+
+ return timeout;
+}
+
+static int kempld_wdt_set_timeout(struct watchdog_device *wdd,
+ unsigned int timeout)
+{
+ struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
+ struct kempld_wdt_stage *pretimeout_stage;
+ struct kempld_wdt_stage *timeout_stage;
+ int ret;
+
+ timeout_stage = &wdt_data->stage[STAGE_TIMEOUT];
+ pretimeout_stage = &wdt_data->stage[STAGE_PRETIMEOUT];
+
+ if (pretimeout_stage->mask && wdt_data->pretimeout > 0)
+ timeout = wdt_data->pretimeout;
+
+ ret = kempld_wdt_set_stage_action(wdt_data, timeout_stage,
+ ACTION_RESET);
+ if (ret)
+ return ret;
+ ret = kempld_wdt_set_stage_timeout(wdt_data, timeout_stage,
+ timeout);
+ if (ret)
+ return ret;
+
+ wdd->timeout = timeout;
+ return 0;
+}
+
+static int kempld_wdt_set_pretimeout(struct watchdog_device *wdd,
+ unsigned int pretimeout)
+{
+ struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
+ struct kempld_wdt_stage *pretimeout_stage;
+ u8 action = ACTION_NONE;
+ int ret;
+
+ pretimeout_stage = &wdt_data->stage[STAGE_PRETIMEOUT];
+
+ if (!pretimeout_stage->mask)
+ return -ENXIO;
+
+ if (pretimeout > wdd->timeout)
+ return -EINVAL;
+
+ if (pretimeout > 0)
+ action = ACTION_NMI;
+
+ ret = kempld_wdt_set_stage_action(wdt_data, pretimeout_stage,
+ action);
+ if (ret)
+ return ret;
+ ret = kempld_wdt_set_stage_timeout(wdt_data, pretimeout_stage,
+ wdd->timeout - pretimeout);
+ if (ret)
+ return ret;
+
+ wdt_data->pretimeout = pretimeout;
+ return 0;
+}
+
+static void kempld_wdt_update_timeouts(struct kempld_wdt_data *wdt_data)
+{
+ struct kempld_device_data *pld = wdt_data->pld;
+ struct kempld_wdt_stage *pretimeout_stage;
+ struct kempld_wdt_stage *timeout_stage;
+ unsigned int pretimeout, timeout;
+
+ pretimeout_stage = &wdt_data->stage[STAGE_PRETIMEOUT];
+ timeout_stage = &wdt_data->stage[STAGE_TIMEOUT];
+
+ kempld_get_mutex(pld);
+ pretimeout = kempld_wdt_get_timeout(wdt_data, pretimeout_stage);
+ timeout = kempld_wdt_get_timeout(wdt_data, timeout_stage);
+ kempld_release_mutex(pld);
+
+ if (pretimeout)
+ wdt_data->pretimeout = timeout;
+ else
+ wdt_data->pretimeout = 0;
+
+ wdt_data->wdd.timeout = pretimeout + timeout;
+}
+
+static int kempld_wdt_start(struct watchdog_device *wdd)
+{
+ struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
+ struct kempld_device_data *pld = wdt_data->pld;
+ u8 status;
+ int ret;
+
+ ret = kempld_wdt_set_timeout(wdd, wdd->timeout);
+ if (ret)
+ return ret;
+
+ kempld_get_mutex(pld);
+ status = kempld_read8(pld, KEMPLD_WDT_CFG);
+ status |= KEMPLD_WDT_CFG_ENABLE;
+ kempld_write8(pld, KEMPLD_WDT_CFG, status);
+ status = kempld_read8(pld, KEMPLD_WDT_CFG);
+ kempld_release_mutex(pld);
+
+ /* Check if the watchdog was enabled */
+ if (!(status & KEMPLD_WDT_CFG_ENABLE))
+ return -EACCES;
+
+ return 0;
+}
+
+static int kempld_wdt_stop(struct watchdog_device *wdd)
+{
+ struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
+ struct kempld_device_data *pld = wdt_data->pld;
+ u8 status;
+
+ kempld_get_mutex(pld);
+ status = kempld_read8(pld, KEMPLD_WDT_CFG);
+ status &= ~KEMPLD_WDT_CFG_ENABLE;
+ kempld_write8(pld, KEMPLD_WDT_CFG, status);
+ status = kempld_read8(pld, KEMPLD_WDT_CFG);
+ kempld_release_mutex(pld);
+
+ /* Check if the watchdog was disabled */
+ if (status & KEMPLD_WDT_CFG_ENABLE)
+ return -EACCES;
+
+ return 0;
+}
+
+static int kempld_wdt_keepalive(struct watchdog_device *wdd)
+{
+ struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
+ struct kempld_device_data *pld = wdt_data->pld;
+
+ kempld_get_mutex(pld);
+ kempld_write8(pld, KEMPLD_WDT_KICK, 'K');
+ kempld_release_mutex(pld);
+
+ return 0;
+}
+
+static long kempld_wdt_ioctl(struct watchdog_device *wdd, unsigned int cmd,
+ unsigned long arg)
+{
+ struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
+ void __user *argp = (void __user *)arg;
+ int ret = -ENOIOCTLCMD;
+ int __user *p = argp;
+ int new_value;
+
+ switch (cmd) {
+ case WDIOC_SETPRETIMEOUT:
+ if (get_user(new_value, p))
+ return -EFAULT;
+ ret = kempld_wdt_set_pretimeout(wdd, new_value);
+ if (ret)
+ return ret;
+ ret = kempld_wdt_keepalive(wdd);
+ break;
+ case WDIOC_GETPRETIMEOUT:
+ ret = put_user(wdt_data->pretimeout, (int *)arg);
+ break;
+ }
+
+ return ret;
+}
+
+static int kempld_wdt_probe_stages(struct watchdog_device *wdd)
+{
+ struct kempld_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
+ struct kempld_device_data *pld = wdt_data->pld;
+ struct kempld_wdt_stage *pretimeout_stage;
+ struct kempld_wdt_stage *timeout_stage;
+ u8 index, data, data_orig;
+ u32 mask;
+ int i, j;
+
+ pretimeout_stage = &wdt_data->stage[STAGE_PRETIMEOUT];
+ timeout_stage = &wdt_data->stage[STAGE_TIMEOUT];
+
+ pretimeout_stage->mask = 0;
+ timeout_stage->mask = 0;
+
+ for (i = 0; i < 3; i++) {
+ index = KEMPLD_WDT_STAGE_TIMEOUT(i);
+ mask = 0;
+
+ kempld_get_mutex(pld);
+ /* Probe each byte individually. */
+ for (j = 0; j < 4; j++) {
+ data_orig = kempld_read8(pld, index + j);
+ kempld_write8(pld, index + j, 0x00);
+ data = kempld_read8(pld, index + j);
+ /* A failed write means this byte is reserved */
+ if (data != 0x00)
+ break;
+ kempld_write8(pld, index + j, data_orig);
+ mask |= 0xff << (j * 8);
+ }
+ kempld_release_mutex(pld);
+
+ /* Assign available stages to timeout and pretimeout */
+ if (!timeout_stage->mask) {
+ timeout_stage->mask = mask;
+ timeout_stage->id = i;
+ } else {
+ if (pld->feature_mask & KEMPLD_FEATURE_BIT_NMI) {
+ pretimeout_stage->mask = timeout_stage->mask;
+ timeout_stage->mask = mask;
+ pretimeout_stage->id = timeout_stage->id;
+ timeout_stage->id = i;
+ }
+ break;
+ }
+ }
+
+ if (!timeout_stage->mask)
+ return -ENODEV;
+
+ return 0;
+}
+
+static struct watchdog_info kempld_wdt_info = {
+ .identity = "KEMPLD Watchdog",
+ .options = WDIOF_SETTIMEOUT |
+ WDIOF_KEEPALIVEPING |
+ WDIOF_MAGICCLOSE |
+ WDIOF_PRETIMEOUT
+};
+
+static struct watchdog_ops kempld_wdt_ops = {
+ .owner = THIS_MODULE,
+ .start = kempld_wdt_start,
+ .stop = kempld_wdt_stop,
+ .ping = kempld_wdt_keepalive,
+ .set_timeout = kempld_wdt_set_timeout,
+ .ioctl = kempld_wdt_ioctl,
+};
+
+static int kempld_wdt_probe(struct platform_device *pdev)
+{
+ struct kempld_device_data *pld = dev_get_drvdata(pdev->dev.parent);
+ struct kempld_wdt_data *wdt_data;
+ struct device *dev = &pdev->dev;
+ struct watchdog_device *wdd;
+ u8 status;
+ int ret = 0;
+
+ wdt_data = devm_kzalloc(dev, sizeof(*wdt_data), GFP_KERNEL);
+ if (!wdt_data)
+ return -ENOMEM;
+
+ wdt_data->pld = pld;
+ wdd = &wdt_data->wdd;
+ wdd->parent = dev;
+
+ kempld_get_mutex(pld);
+ status = kempld_read8(pld, KEMPLD_WDT_CFG);
+ kempld_release_mutex(pld);
+
+ /* Enable nowayout if watchdog is already locked */
+ if (status & (KEMPLD_WDT_CFG_ENABLE_LOCK |
+ KEMPLD_WDT_CFG_GLOBAL_LOCK)) {
+ if (!nowayout)
+ dev_warn(dev,
+ "Forcing nowayout - watchdog lock enabled!\n");
+ nowayout = true;
+ }
+
+ wdd->info = &kempld_wdt_info;
+ wdd->ops = &kempld_wdt_ops;
+
+ watchdog_set_drvdata(wdd, wdt_data);
+ watchdog_set_nowayout(wdd, nowayout);
+
+ ret = kempld_wdt_probe_stages(wdd);
+ if (ret)
+ return ret;
+
+ kempld_wdt_set_timeout(wdd, timeout);
+ kempld_wdt_set_pretimeout(wdd, pretimeout);
+
+ /* Check if watchdog is already enabled */
+ if (status & KEMPLD_WDT_CFG_ENABLE) {
+ /* Get current watchdog settings */
+ kempld_wdt_update_timeouts(wdt_data);
+ dev_info(dev, "Watchdog was already enabled\n");
+ }
+
+ platform_set_drvdata(pdev, wdt_data);
+ ret = watchdog_register_device(wdd);
+ if (ret)
+ return ret;
+
+ dev_info(dev, "Watchdog registered with %ds timeout\n", wdd->timeout);
+
+ return 0;
+}
+
+static void kempld_wdt_shutdown(struct platform_device *pdev)
+{
+ struct kempld_wdt_data *wdt_data = platform_get_drvdata(pdev);
+
+ kempld_wdt_stop(&wdt_data->wdd);
+}
+
+static int kempld_wdt_remove(struct platform_device *pdev)
+{
+ struct kempld_wdt_data *wdt_data = platform_get_drvdata(pdev);
+ struct watchdog_device *wdd = &wdt_data->wdd;
+ int ret = 0;
+
+ if (!nowayout)
+ ret = kempld_wdt_stop(wdd);
+ watchdog_unregister_device(wdd);
+
+ return ret;
+}
+
+#ifdef CONFIG_PM
+/* Disable watchdog if it is active during suspend */
+static int kempld_wdt_suspend(struct platform_device *pdev,
+ pm_message_t message)
+{
+ struct kempld_wdt_data *wdt_data = platform_get_drvdata(pdev);
+ struct kempld_device_data *pld = wdt_data->pld;
+ struct watchdog_device *wdd = &wdt_data->wdd;
+
+ kempld_get_mutex(pld);
+ wdt_data->pm_status_store = kempld_read8(pld, KEMPLD_WDT_CFG);
+ kempld_release_mutex(pld);
+
+ kempld_wdt_update_timeouts(wdt_data);
+
+ if (wdt_data->pm_status_store & KEMPLD_WDT_CFG_ENABLE)
+ return kempld_wdt_stop(wdd);
+
+ return 0;
+}
+
+/* Enable watchdog and configure it if necessary */
+static int kempld_wdt_resume(struct platform_device *pdev)
+{
+ struct kempld_wdt_data *wdt_data = platform_get_drvdata(pdev);
+ struct watchdog_device *wdd = &wdt_data->wdd;
+
+ /*
+ * If watchdog was stopped before suspend be sure it gets disabled
+ * again, for the case BIOS has enabled it during resume
+ */
+ if (wdt_data->pm_status_store & KEMPLD_WDT_CFG_ENABLE)
+ return kempld_wdt_start(wdd);
+ else
+ return kempld_wdt_stop(wdd);
+}
+#else
+#define kempld_wdt_suspend NULL
+#define kempld_wdt_resume NULL
+#endif
+
+static struct platform_driver kempld_wdt_driver = {
+ .driver = {
+ .name = "kempld-wdt",
+ .owner = THIS_MODULE,
+ },
+ .probe = kempld_wdt_probe,
+ .remove = kempld_wdt_remove,
+ .shutdown = kempld_wdt_shutdown,
+ .suspend = kempld_wdt_suspend,
+ .resume = kempld_wdt_resume,
+};
+
+module_platform_driver(kempld_wdt_driver);
+
+MODULE_DESCRIPTION("KEM PLD Watchdog Driver");
+MODULE_AUTHOR("Michael Brunner <michael.brunner@kontron.com>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
