diff options
Diffstat (limited to 'drivers/watchdog/intel-mid_wdt.c')
| -rw-r--r-- | drivers/watchdog/intel-mid_wdt.c | 206 |
1 files changed, 206 insertions, 0 deletions
diff --git a/drivers/watchdog/intel-mid_wdt.c b/drivers/watchdog/intel-mid_wdt.c new file mode 100644 index 000000000..fb7fae750 --- /dev/null +++ b/drivers/watchdog/intel-mid_wdt.c @@ -0,0 +1,206 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * intel-mid_wdt: generic Intel MID SCU watchdog driver + * + * Platforms supported so far: + * - Merrifield only + * + * Copyright (C) 2014 Intel Corporation. All rights reserved. + * Contact: David Cohen <david.a.cohen@linux.intel.com> + */ + +#include <linux/interrupt.h> +#include <linux/module.h> +#include <linux/nmi.h> +#include <linux/platform_device.h> +#include <linux/watchdog.h> +#include <linux/platform_data/intel-mid_wdt.h> + +#include <asm/intel_scu_ipc.h> +#include <asm/intel-mid.h> + +#define IPC_WATCHDOG 0xf8 + +#define MID_WDT_PRETIMEOUT 15 +#define MID_WDT_TIMEOUT_MIN (1 + MID_WDT_PRETIMEOUT) +#define MID_WDT_TIMEOUT_MAX 170 +#define MID_WDT_DEFAULT_TIMEOUT 90 + +/* SCU watchdog messages */ +enum { + SCU_WATCHDOG_START = 0, + SCU_WATCHDOG_STOP, + SCU_WATCHDOG_KEEPALIVE, +}; + +struct mid_wdt { + struct watchdog_device wd; + struct device *dev; + struct intel_scu_ipc_dev *scu; +}; + +static inline int +wdt_command(struct mid_wdt *mid, int sub, const void *in, size_t inlen, size_t size) +{ + struct intel_scu_ipc_dev *scu = mid->scu; + + return intel_scu_ipc_dev_command_with_size(scu, IPC_WATCHDOG, sub, in, + inlen, size, NULL, 0); +} + +static int wdt_start(struct watchdog_device *wd) +{ + struct mid_wdt *mid = watchdog_get_drvdata(wd); + int ret, in_size; + int timeout = wd->timeout; + struct ipc_wd_start { + u32 pretimeout; + u32 timeout; + } ipc_wd_start = { timeout - MID_WDT_PRETIMEOUT, timeout }; + + /* + * SCU expects the input size for watchdog IPC to be 2 which is the + * size of the structure in dwords. SCU IPC normally takes bytes + * but this is a special case where we specify size to be different + * than inlen. + */ + in_size = DIV_ROUND_UP(sizeof(ipc_wd_start), 4); + + ret = wdt_command(mid, SCU_WATCHDOG_START, &ipc_wd_start, + sizeof(ipc_wd_start), in_size); + if (ret) + dev_crit(mid->dev, "error starting watchdog: %d\n", ret); + + return ret; +} + +static int wdt_ping(struct watchdog_device *wd) +{ + struct mid_wdt *mid = watchdog_get_drvdata(wd); + int ret; + + ret = wdt_command(mid, SCU_WATCHDOG_KEEPALIVE, NULL, 0, 0); + if (ret) + dev_crit(mid->dev, "Error executing keepalive: %d\n", ret); + + return ret; +} + +static int wdt_stop(struct watchdog_device *wd) +{ + struct mid_wdt *mid = watchdog_get_drvdata(wd); + int ret; + + ret = wdt_command(mid, SCU_WATCHDOG_STOP, NULL, 0, 0); + if (ret) + dev_crit(mid->dev, "Error stopping watchdog: %d\n", ret); + + return ret; +} + +static irqreturn_t mid_wdt_irq(int irq, void *dev_id) +{ + panic("Kernel Watchdog"); + + /* This code should not be reached */ + return IRQ_HANDLED; +} + +static const struct watchdog_info mid_wdt_info = { + .identity = "Intel MID SCU watchdog", + .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE, +}; + +static const struct watchdog_ops mid_wdt_ops = { + .owner = THIS_MODULE, + .start = wdt_start, + .stop = wdt_stop, + .ping = wdt_ping, +}; + +static int mid_wdt_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct watchdog_device *wdt_dev; + struct intel_mid_wdt_pdata *pdata = dev->platform_data; + struct mid_wdt *mid; + int ret; + + if (!pdata) { + dev_err(dev, "missing platform data\n"); + return -EINVAL; + } + + if (pdata->probe) { + ret = pdata->probe(pdev); + if (ret) + return ret; + } + + mid = devm_kzalloc(dev, sizeof(*mid), GFP_KERNEL); + if (!mid) + return -ENOMEM; + + mid->dev = dev; + wdt_dev = &mid->wd; + + wdt_dev->info = &mid_wdt_info; + wdt_dev->ops = &mid_wdt_ops; + wdt_dev->min_timeout = MID_WDT_TIMEOUT_MIN; + wdt_dev->max_timeout = MID_WDT_TIMEOUT_MAX; + wdt_dev->timeout = MID_WDT_DEFAULT_TIMEOUT; + wdt_dev->parent = dev; + + watchdog_set_nowayout(wdt_dev, WATCHDOG_NOWAYOUT); + watchdog_set_drvdata(wdt_dev, mid); + + mid->scu = devm_intel_scu_ipc_dev_get(dev); + if (!mid->scu) + return -EPROBE_DEFER; + + ret = devm_request_irq(dev, pdata->irq, mid_wdt_irq, + IRQF_SHARED | IRQF_NO_SUSPEND, "watchdog", + wdt_dev); + if (ret) { + dev_err(dev, "error requesting warning irq %d\n", pdata->irq); + return ret; + } + + /* + * The firmware followed by U-Boot leaves the watchdog running + * with the default threshold which may vary. When we get here + * we should make a decision to prevent any side effects before + * user space daemon will take care of it. The best option, + * taking into consideration that there is no way to read values + * back from hardware, is to enforce watchdog being run with + * deterministic values. + */ + ret = wdt_start(wdt_dev); + if (ret) + return ret; + + /* Make sure the watchdog is serviced */ + set_bit(WDOG_HW_RUNNING, &wdt_dev->status); + + ret = devm_watchdog_register_device(dev, wdt_dev); + if (ret) + return ret; + + dev_info(dev, "Intel MID watchdog device probed\n"); + + return 0; +} + +static struct platform_driver mid_wdt_driver = { + .probe = mid_wdt_probe, + .driver = { + .name = "intel_mid_wdt", + }, +}; + +module_platform_driver(mid_wdt_driver); + +MODULE_AUTHOR("David Cohen <david.a.cohen@linux.intel.com>"); +MODULE_DESCRIPTION("Watchdog Driver for Intel MID platform"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:intel_mid_wdt"); |