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Subject[PATCH v5 3/4] watchdog: add meson secure watchdog driver
Date
The watchdog controller on the Meson-A/C series SoCs is moved to secure
world, watchdog operation needs to be done in secure EL3 mode via ATF,
Non-secure world can call SMC instruction to trap to AFT for watchdog
operation.

Signed-off-by: Xingyu Chen <xingyu.chen@amlogic.com>
---
drivers/watchdog/Kconfig | 16 ++++
drivers/watchdog/Makefile | 1 +
drivers/watchdog/meson_sec_wdt.c | 188 +++++++++++++++++++++++++++++++++++++++
3 files changed, 205 insertions(+)
create mode 100644 drivers/watchdog/meson_sec_wdt.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 1679e0d..5f88325 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -826,6 +826,22 @@ config MESON_GXBB_WATCHDOG
To compile this driver as a module, choose M here: the
module will be called meson_gxbb_wdt.

+config MESON_SEC_WATCHDOG
+ tristate "Amlogic Meson Secure watchdog support"
+ depends on MESON_SM
+ select WATCHDOG_CORE
+ help
+ The watchdog controller on the Meson-A/C series SoCs is moved to
+ secure world, watchdog operation needs to be done in secure EL3
+ mode via ATF, non-secure world can call SMC instruction to trap
+ to ATF for the watchdog operation.
+
+ Say Y here if watchdog controller on Meson SoCs is located in
+ secure world.
+
+ To compile this driver as a module, choose M here: the
+ module will be called meson_sec_wdt.
+
config MESON_WATCHDOG
tristate "Amlogic Meson SoCs watchdog support"
depends on ARCH_MESON || COMPILE_TEST
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 2ee352b..5e6b73d 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -78,6 +78,7 @@ obj-$(CONFIG_QCOM_WDT) += qcom-wdt.o
obj-$(CONFIG_BCM_KONA_WDT) += bcm_kona_wdt.o
obj-$(CONFIG_TEGRA_WATCHDOG) += tegra_wdt.o
obj-$(CONFIG_MESON_GXBB_WATCHDOG) += meson_gxbb_wdt.o
+obj-$(CONFIG_MESON_SEC_WATCHDOG) += meson_sec_wdt.o
obj-$(CONFIG_MESON_WATCHDOG) += meson_wdt.o
obj-$(CONFIG_MEDIATEK_WATCHDOG) += mtk_wdt.o
obj-$(CONFIG_DIGICOLOR_WATCHDOG) += digicolor_wdt.o
diff --git a/drivers/watchdog/meson_sec_wdt.c b/drivers/watchdog/meson_sec_wdt.c
new file mode 100644
index 00000000..7975522
--- /dev/null
+++ b/drivers/watchdog/meson_sec_wdt.c
@@ -0,0 +1,188 @@
+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+/*
+ * Copyright (c) 2019 Amlogic, Inc. All rights reserved.
+ * Author: Xingyu Chen <xingyu.chen@amlogic.com>
+ *
+ */
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+#include <linux/watchdog.h>
+#include <linux/firmware/meson/meson_sm.h>
+
+#define MESON_SIP_WDT_DISABLE 0x1
+#define MESON_SIP_WDT_ENABLE 0x2
+#define MESON_SIP_WDT_PING 0x3
+#define MESON_SIP_WDT_INIT 0x4
+#define MESON_SIP_WDT_RESETNOW 0x5
+#define MESON_SIP_WDT_SETTIMEOUT 0x6
+#define MESON_SIP_WDT_GETTIMELEFT 0x7
+
+#define DEFAULT_TIMEOUT 30 /* seconds */
+
+/*
+ * Watchdog timer tick is set to 1ms in secfw side, and tick count is
+ * stored in the bit[16-31] of WATCHDOG_CNT register, so the maximum
+ * timeout value is 0xffff ms.
+ */
+#define MAX_TIMEOUT_MS 0xFFFF
+
+struct meson_sec_wdt {
+ struct watchdog_device wdt_dev;
+ struct meson_sm_firmware *fw;
+};
+
+static int meson_sec_wdt_start(struct watchdog_device *wdt_dev)
+{
+ struct meson_sec_wdt *data = watchdog_get_drvdata(wdt_dev);
+
+ return meson_sm_call(data->fw, SM_A1_WATCHDOG_OPS, NULL,
+ MESON_SIP_WDT_ENABLE, 0, 0, 0, 0);
+}
+
+static int meson_sec_wdt_stop(struct watchdog_device *wdt_dev)
+{
+ struct meson_sec_wdt *data = watchdog_get_drvdata(wdt_dev);
+
+ return meson_sm_call(data->fw, SM_A1_WATCHDOG_OPS, NULL,
+ MESON_SIP_WDT_DISABLE, 0, 0, 0, 0);
+}
+
+static int meson_sec_wdt_ping(struct watchdog_device *wdt_dev)
+{
+ struct meson_sec_wdt *data = watchdog_get_drvdata(wdt_dev);
+
+ return meson_sm_call(data->fw, SM_A1_WATCHDOG_OPS, NULL,
+ MESON_SIP_WDT_PING, 0, 0, 0, 0);
+}
+
+static int meson_sec_wdt_set_timeout(struct watchdog_device *wdt_dev,
+ unsigned int timeout)
+{
+ struct meson_sec_wdt *data = watchdog_get_drvdata(wdt_dev);
+
+ wdt_dev->timeout = timeout;
+
+ return meson_sm_call(data->fw, SM_A1_WATCHDOG_OPS, NULL,
+ MESON_SIP_WDT_SETTIMEOUT,
+ wdt_dev->timeout * 1000, 0, 0, 0);
+}
+
+static unsigned int meson_sec_wdt_get_timeleft(struct watchdog_device *wdt_dev)
+{
+ int ret;
+ unsigned int timeleft;
+ struct meson_sec_wdt *data = watchdog_get_drvdata(wdt_dev);
+
+ ret = meson_sm_call(data->fw, SM_A1_WATCHDOG_OPS, &timeleft,
+ MESON_SIP_WDT_GETTIMELEFT, 0, 0, 0, 0);
+
+ if (ret)
+ return 0;
+
+ return timeleft;
+}
+
+static const struct watchdog_ops meson_sec_wdt_ops = {
+ .start = meson_sec_wdt_start,
+ .stop = meson_sec_wdt_stop,
+ .ping = meson_sec_wdt_ping,
+ .set_timeout = meson_sec_wdt_set_timeout,
+ .get_timeleft = meson_sec_wdt_get_timeleft,
+};
+
+static const struct watchdog_info meson_sec_wdt_info = {
+ .identity = "Meson Secure Watchdog Timer",
+ .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
+};
+
+static int __maybe_unused meson_sec_wdt_resume(struct device *dev)
+{
+ struct meson_sec_wdt *data = dev_get_drvdata(dev);
+
+ if (watchdog_active(&data->wdt_dev))
+ return meson_sec_wdt_start(&data->wdt_dev);
+
+ return 0;
+}
+
+static int __maybe_unused meson_sec_wdt_suspend(struct device *dev)
+{
+ struct meson_sec_wdt *data = dev_get_drvdata(dev);
+
+ if (watchdog_active(&data->wdt_dev))
+ return meson_sec_wdt_stop(&data->wdt_dev);
+
+ return 0;
+}
+
+static const struct dev_pm_ops meson_sec_wdt_pm_ops = {
+ SET_SYSTEM_SLEEP_PM_OPS(meson_sec_wdt_suspend, meson_sec_wdt_resume)
+};
+
+static const struct of_device_id meson_sec_wdt_dt_ids[] = {
+ { .compatible = "amlogic,meson-sec-wdt", },
+ { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, meson_sec_wdt_dt_ids);
+
+static int meson_sec_wdt_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct meson_sec_wdt *data;
+ struct device_node *sm_np;
+ int ret;
+
+ data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ sm_np = of_find_compatible_node(NULL, NULL, "amlogic,meson-gxbb-sm");
+ if (!sm_np) {
+ dev_err(&pdev->dev, "no secure-monitor node\n");
+ return -EINVAL;
+ }
+
+ data->fw = meson_sm_get(sm_np);
+ of_node_put(sm_np);
+ if (!data->fw)
+ return -EPROBE_DEFER;
+
+ platform_set_drvdata(pdev, data);
+
+ data->wdt_dev.parent = dev;
+ data->wdt_dev.info = &meson_sec_wdt_info;
+ data->wdt_dev.ops = &meson_sec_wdt_ops;
+ data->wdt_dev.max_hw_heartbeat_ms = MAX_TIMEOUT_MS;
+ data->wdt_dev.min_timeout = 1;
+ data->wdt_dev.timeout = DEFAULT_TIMEOUT;
+ watchdog_set_drvdata(&data->wdt_dev, data);
+ watchdog_init_timeout(&data->wdt_dev, 0, dev);
+
+ ret = meson_sm_call(data->fw, SM_A1_WATCHDOG_OPS, NULL,
+ MESON_SIP_WDT_INIT,
+ data->wdt_dev.timeout * 1000, 0, 0, 0);
+ if (ret)
+ return ret;
+
+ watchdog_stop_on_reboot(&data->wdt_dev);
+
+ return devm_watchdog_register_device(dev, &data->wdt_dev);
+}
+
+static struct platform_driver meson_sec_wdt_driver = {
+ .probe = meson_sec_wdt_probe,
+ .driver = {
+ .name = "meson-sec-wdt",
+ .pm = &meson_sec_wdt_pm_ops,
+ .of_match_table = meson_sec_wdt_dt_ids,
+ },
+};
+
+module_platform_driver(meson_sec_wdt_driver);
+
+MODULE_AUTHOR("Xingyu Chen <xingyu.chen@amlogic.com>");
+MODULE_DESCRIPTION("Amlogic Secure Watchdog Timer Driver");
+MODULE_LICENSE("Dual MIT/GPL");
--
2.7.4
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