diff options
Diffstat (limited to 'drivers/watchdog/gxp-wdt.c')
| -rw-r--r-- | drivers/watchdog/gxp-wdt.c | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/drivers/watchdog/gxp-wdt.c b/drivers/watchdog/gxp-wdt.c new file mode 100644 index 000000000..2fd85be88 --- /dev/null +++ b/drivers/watchdog/gxp-wdt.c @@ -0,0 +1,175 @@ +// 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"); +MODULE_LICENSE("GPL"); |