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path: root/drivers/watchdog/gxp-wdt.c
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Diffstat (limited to 'drivers/watchdog/gxp-wdt.c')
-rw-r--r--drivers/watchdog/gxp-wdt.c174
1 files changed, 174 insertions, 0 deletions
diff --git a/drivers/watchdog/gxp-wdt.c b/drivers/watchdog/gxp-wdt.c
new file mode 100644
index 000000000000..b0b2d7a6fdde
--- /dev/null
+++ b/drivers/watchdog/gxp-wdt.c
@@ -0,0 +1,174 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (C) 2022 Hewlett-Packard Enterprise Development Company, L.P. */
+
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+#include <linux/watchdog.h>
+
+#define MASK_WDGCS_ENABLE 0x01
+#define MASK_WDGCS_RELOAD 0x04
+#define MASK_WDGCS_NMIEN 0x08
+#define MASK_WDGCS_WARN 0x80
+
+#define WDT_MAX_TIMEOUT_MS 655350
+#define WDT_DEFAULT_TIMEOUT 30
+#define SECS_TO_WDOG_TICKS(x) ((x) * 100)
+#define WDOG_TICKS_TO_SECS(x) ((x) / 100)
+
+#define GXP_WDT_CNT_OFS 0x10
+#define GXP_WDT_CTRL_OFS 0x16
+
+struct gxp_wdt {
+ void __iomem *base;
+ struct watchdog_device wdd;
+};
+
+static void gxp_wdt_enable_reload(struct gxp_wdt *drvdata)
+{
+ u8 val;
+
+ val = readb(drvdata->base + GXP_WDT_CTRL_OFS);
+ val |= (MASK_WDGCS_ENABLE | MASK_WDGCS_RELOAD);
+ writeb(val, drvdata->base + GXP_WDT_CTRL_OFS);
+}
+
+static int gxp_wdt_start(struct watchdog_device *wdd)
+{
+ struct gxp_wdt *drvdata = watchdog_get_drvdata(wdd);
+
+ writew(SECS_TO_WDOG_TICKS(wdd->timeout), drvdata->base + GXP_WDT_CNT_OFS);
+ gxp_wdt_enable_reload(drvdata);
+ return 0;
+}
+
+static int gxp_wdt_stop(struct watchdog_device *wdd)
+{
+ struct gxp_wdt *drvdata = watchdog_get_drvdata(wdd);
+ u8 val;
+
+ val = readb_relaxed(drvdata->base + GXP_WDT_CTRL_OFS);
+ val &= ~MASK_WDGCS_ENABLE;
+ writeb(val, drvdata->base + GXP_WDT_CTRL_OFS);
+ return 0;
+}
+
+static int gxp_wdt_set_timeout(struct watchdog_device *wdd,
+ unsigned int timeout)
+{
+ struct gxp_wdt *drvdata = watchdog_get_drvdata(wdd);
+ u32 actual;
+
+ wdd->timeout = timeout;
+ actual = min(timeout * 100, wdd->max_hw_heartbeat_ms / 10);
+ writew(actual, drvdata->base + GXP_WDT_CNT_OFS);
+
+ return 0;
+}
+
+static unsigned int gxp_wdt_get_timeleft(struct watchdog_device *wdd)
+{
+ struct gxp_wdt *drvdata = watchdog_get_drvdata(wdd);
+ u32 val = readw(drvdata->base + GXP_WDT_CNT_OFS);
+
+ return WDOG_TICKS_TO_SECS(val);
+}
+
+static int gxp_wdt_ping(struct watchdog_device *wdd)
+{
+ struct gxp_wdt *drvdata = watchdog_get_drvdata(wdd);
+
+ gxp_wdt_enable_reload(drvdata);
+ return 0;
+}
+
+static int gxp_restart(struct watchdog_device *wdd, unsigned long action,
+ void *data)
+{
+ struct gxp_wdt *drvdata = watchdog_get_drvdata(wdd);
+
+ writew(1, drvdata->base + GXP_WDT_CNT_OFS);
+ gxp_wdt_enable_reload(drvdata);
+ mdelay(100);
+ return 0;
+}
+
+static const struct watchdog_ops gxp_wdt_ops = {
+ .owner = THIS_MODULE,
+ .start = gxp_wdt_start,
+ .stop = gxp_wdt_stop,
+ .ping = gxp_wdt_ping,
+ .set_timeout = gxp_wdt_set_timeout,
+ .get_timeleft = gxp_wdt_get_timeleft,
+ .restart = gxp_restart,
+};
+
+static const struct watchdog_info gxp_wdt_info = {
+ .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
+ .identity = "HPE GXP Watchdog timer",
+};
+
+static int gxp_wdt_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct gxp_wdt *drvdata;
+ int err;
+ u8 val;
+
+ drvdata = devm_kzalloc(dev, sizeof(struct gxp_wdt), GFP_KERNEL);
+ if (!drvdata)
+ return -ENOMEM;
+
+ /*
+ * The register area where the timer and watchdog reside is disarranged.
+ * Hence mapping individual register blocks for the timer and watchdog
+ * is not recommended as they would have access to each others
+ * registers. Based on feedback the watchdog is no longer part of the
+ * device tree file and the timer driver now creates the watchdog as a
+ * child device. During the watchdogs creation, the timer driver passes
+ * the base address to the watchdog over the private interface.
+ */
+
+ drvdata->base = (void __iomem *)dev->platform_data;
+
+ drvdata->wdd.info = &gxp_wdt_info;
+ drvdata->wdd.ops = &gxp_wdt_ops;
+ drvdata->wdd.max_hw_heartbeat_ms = WDT_MAX_TIMEOUT_MS;
+ drvdata->wdd.parent = dev;
+ drvdata->wdd.timeout = WDT_DEFAULT_TIMEOUT;
+
+ watchdog_set_drvdata(&drvdata->wdd, drvdata);
+ watchdog_set_nowayout(&drvdata->wdd, WATCHDOG_NOWAYOUT);
+
+ val = readb(drvdata->base + GXP_WDT_CTRL_OFS);
+
+ if (val & MASK_WDGCS_ENABLE)
+ set_bit(WDOG_HW_RUNNING, &drvdata->wdd.status);
+
+ watchdog_set_restart_priority(&drvdata->wdd, 128);
+
+ watchdog_stop_on_reboot(&drvdata->wdd);
+ err = devm_watchdog_register_device(dev, &drvdata->wdd);
+ if (err) {
+ dev_err(dev, "Failed to register watchdog device");
+ return err;
+ }
+
+ dev_info(dev, "HPE GXP watchdog timer");
+
+ return 0;
+}
+
+static struct platform_driver gxp_wdt_driver = {
+ .probe = gxp_wdt_probe,
+ .driver = {
+ .name = "gxp-wdt",
+ },
+};
+module_platform_driver(gxp_wdt_driver);
+
+MODULE_AUTHOR("Nick Hawkins <nick.hawkins@hpe.com>");
+MODULE_AUTHOR("Jean-Marie Verdun <verdun@hpe.com>");
+MODULE_DESCRIPTION("Driver for GXP watchdog timer");