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- // 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 <[email protected]>");
- MODULE_AUTHOR("Jean-Marie Verdun <[email protected]>");
- MODULE_DESCRIPTION("Driver for GXP watchdog timer");
- MODULE_LICENSE("GPL");
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