summaryrefslogtreecommitdiffstats
path: root/drivers/watchdog/arm_smc_wdt.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/watchdog/arm_smc_wdt.c')
-rw-r--r--drivers/watchdog/arm_smc_wdt.c188
1 files changed, 188 insertions, 0 deletions
diff --git a/drivers/watchdog/arm_smc_wdt.c b/drivers/watchdog/arm_smc_wdt.c
new file mode 100644
index 000000000..8f3d0c3a0
--- /dev/null
+++ b/drivers/watchdog/arm_smc_wdt.c
@@ -0,0 +1,188 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ARM Secure Monitor Call watchdog driver
+ *
+ * Copyright 2020 Google LLC.
+ * Julius Werner <jwerner@chromium.org>
+ * Based on mtk_wdt.c
+ */
+
+#include <linux/arm-smccc.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+#include <linux/watchdog.h>
+#include <uapi/linux/psci.h>
+
+#define DRV_NAME "arm_smc_wdt"
+#define DRV_VERSION "1.0"
+
+enum smcwd_call {
+ SMCWD_INIT = 0,
+ SMCWD_SET_TIMEOUT = 1,
+ SMCWD_ENABLE = 2,
+ SMCWD_PET = 3,
+ SMCWD_GET_TIMELEFT = 4,
+};
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+static unsigned int timeout;
+
+static int smcwd_call(struct watchdog_device *wdd, enum smcwd_call call,
+ unsigned long arg, struct arm_smccc_res *res)
+{
+ struct arm_smccc_res local_res;
+
+ if (!res)
+ res = &local_res;
+
+ arm_smccc_smc((u32)(uintptr_t)watchdog_get_drvdata(wdd), call, arg, 0,
+ 0, 0, 0, 0, res);
+
+ if (res->a0 == PSCI_RET_NOT_SUPPORTED)
+ return -ENODEV;
+ if (res->a0 == PSCI_RET_INVALID_PARAMS)
+ return -EINVAL;
+ if (res->a0 != PSCI_RET_SUCCESS)
+ return -EIO;
+ return 0;
+}
+
+static int smcwd_ping(struct watchdog_device *wdd)
+{
+ return smcwd_call(wdd, SMCWD_PET, 0, NULL);
+}
+
+static unsigned int smcwd_get_timeleft(struct watchdog_device *wdd)
+{
+ struct arm_smccc_res res;
+
+ smcwd_call(wdd, SMCWD_GET_TIMELEFT, 0, &res);
+ if (res.a0)
+ return 0;
+ return res.a1;
+}
+
+static int smcwd_set_timeout(struct watchdog_device *wdd, unsigned int timeout)
+{
+ int res;
+
+ res = smcwd_call(wdd, SMCWD_SET_TIMEOUT, timeout, NULL);
+ if (!res)
+ wdd->timeout = timeout;
+ return res;
+}
+
+static int smcwd_stop(struct watchdog_device *wdd)
+{
+ return smcwd_call(wdd, SMCWD_ENABLE, 0, NULL);
+}
+
+static int smcwd_start(struct watchdog_device *wdd)
+{
+ return smcwd_call(wdd, SMCWD_ENABLE, 1, NULL);
+}
+
+static const struct watchdog_info smcwd_info = {
+ .identity = DRV_NAME,
+ .options = WDIOF_SETTIMEOUT |
+ WDIOF_KEEPALIVEPING |
+ WDIOF_MAGICCLOSE,
+};
+
+static const struct watchdog_ops smcwd_ops = {
+ .start = smcwd_start,
+ .stop = smcwd_stop,
+ .ping = smcwd_ping,
+ .set_timeout = smcwd_set_timeout,
+};
+
+static const struct watchdog_ops smcwd_timeleft_ops = {
+ .start = smcwd_start,
+ .stop = smcwd_stop,
+ .ping = smcwd_ping,
+ .set_timeout = smcwd_set_timeout,
+ .get_timeleft = smcwd_get_timeleft,
+};
+
+static int smcwd_probe(struct platform_device *pdev)
+{
+ struct watchdog_device *wdd;
+ int err;
+ struct arm_smccc_res res;
+ u32 smc_func_id;
+
+ wdd = devm_kzalloc(&pdev->dev, sizeof(*wdd), GFP_KERNEL);
+ if (!wdd)
+ return -ENOMEM;
+ platform_set_drvdata(pdev, wdd);
+
+ if (of_property_read_u32(pdev->dev.of_node, "arm,smc-id",
+ &smc_func_id))
+ smc_func_id = 0x82003D06;
+ watchdog_set_drvdata(wdd, (void *)(uintptr_t)smc_func_id);
+
+ err = smcwd_call(wdd, SMCWD_INIT, 0, &res);
+ if (err < 0)
+ return err;
+
+ wdd->info = &smcwd_info;
+ /* get_timeleft is optional */
+ if (smcwd_call(wdd, SMCWD_GET_TIMELEFT, 0, NULL))
+ wdd->ops = &smcwd_ops;
+ else
+ wdd->ops = &smcwd_timeleft_ops;
+ wdd->timeout = res.a2;
+ wdd->max_timeout = res.a2;
+ wdd->min_timeout = res.a1;
+ wdd->parent = &pdev->dev;
+
+ watchdog_stop_on_reboot(wdd);
+ watchdog_stop_on_unregister(wdd);
+ watchdog_set_nowayout(wdd, nowayout);
+ watchdog_init_timeout(wdd, timeout, &pdev->dev);
+ err = smcwd_set_timeout(wdd, wdd->timeout);
+ if (err)
+ return err;
+
+ err = devm_watchdog_register_device(&pdev->dev, wdd);
+ if (err)
+ return err;
+
+ dev_info(&pdev->dev,
+ "Watchdog registered (timeout=%d sec, nowayout=%d)\n",
+ wdd->timeout, nowayout);
+
+ return 0;
+}
+
+static const struct of_device_id smcwd_dt_ids[] = {
+ { .compatible = "arm,smc-wdt" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, smcwd_dt_ids);
+
+static struct platform_driver smcwd_driver = {
+ .probe = smcwd_probe,
+ .driver = {
+ .name = DRV_NAME,
+ .of_match_table = smcwd_dt_ids,
+ },
+};
+
+module_platform_driver(smcwd_driver);
+
+module_param(timeout, uint, 0);
+MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");
+
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
+ __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Julius Werner <jwerner@chromium.org>");
+MODULE_DESCRIPTION("ARM Secure Monitor Call Watchdog Driver");
+MODULE_VERSION(DRV_VERSION);