[PATCH v6 0/5] add meson secure watchdog driver

[PATCH v6 0/5] add meson secure watchdog driver

[Xingyu Chen]

The watchdog controller on the Meson-A/C series SoCs is moved to secure world,
We have to call SMC instruction to trap the ATF for watchdog operation. These
operations are different from previous SoCs, so we introduce a new watchdog
driver to support this kind of SoCs.

Changes since v5 at [4]:
- take the wdt node as child node of secure-monitor
- update dt-binding description
- invoke of_platform_default_populate() instantiate wdt device according to Rob's suggestion at [5]
- find the secure-monitor node through the wdt parent node instead of of_find_compatible_node()
- add Guenter's Reviewed-by

Changes since v4 at [3]:
- add watchdog node in dts, and introduce a new optional property "timeout-sec"
- add dt-binding for meson secure watchdog
- instantiate wdt device through dts node instead of platform_device_register_simple()

Changes since v3 at [2]:
- add SM_A1_ prefix for WATCHDOG_OPS
- remove phandle to secure-monitor node
- remove watchdog node from dts, and register wdt device by platform_device_register_simple()
- remove dt-binding for meson secure watchdog
- use the msec as unit of timeout parameter which is passed to fw side

Changes since v2 at [1]:
- remove useless dependency in Kconfig
- return zero when getting left time value fails

Changes since v1 at [0]:
- add a new dependency in Kconfig
- simplify/add the return operation
- remove useless ping operation when setting the timeout
- fix some return values
- fix the license statement

[0]:https://lore.kernel.org/linux-amlogic/1570874721-36077-1-git-send-email-xingyu.chen@amlogic.com
[1]:https://lore.kernel.org/linux-amlogic/1571387622-35132-1-git-send-email-xingyu.chen@amlogic.com
[2]:https://lore.kernel.org/linux-amlogic/1571983984-11771-1-git-send-email-xingyu.chen@amlogic.com
[3]:https://lore.kernel.org/linux-amlogic/1574685218-31164-1-git-send-email-xingyu.chen@amlogic.com
[4]:https://lore.kernel.org/linux-amlogic/1576153187-28378-1-git-send-email-xingyu.chen@amlogic.com
[5]:https://patchwork.kernel.org/patch/11288017

Xingyu Chen (5):
  firmware: meson_sm: add new SMC ID support for accessing secure
    watchdog
  firmware: meson_sm: populate platform device based on the child node
  dt-bindings: watchdog: add new binding for meson secure watchdog
  watchdog: add meson secure watchdog driver
  arm64: dts: a1: add secure watchdog controller

 .../bindings/watchdog/amlogic,meson-sec-wdt.yaml   |  40 +++++
 arch/arm64/boot/dts/amlogic/meson-a1.dtsi          |   6 +
 drivers/firmware/meson/meson_sm.c                  |   3 +
 drivers/watchdog/Kconfig                           |  16 ++
 drivers/watchdog/Makefile                          |   1 +
 drivers/watchdog/meson_sec_wdt.c                   | 185 +++++++++++++++++++++
 include/linux/firmware/meson/meson_sm.h            |   1 +
 7 files changed, 252 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/watchdog/amlogic,meson-sec-wdt.yaml
 create mode 100644 drivers/watchdog/meson_sec_wdt.c

-- 
2.7.4

[PATCH v6 1/5] firmware: meson_sm: add new SMC ID support for accessing secure watchdog

[Xingyu Chen]

The new SMC ID is used to access secure registers by meson secure
watchdog driver.

Signed-off-by: Xingyu Chen <xingyu.chen@amlogic.com>
---
 drivers/firmware/meson/meson_sm.c       | 1 +
 include/linux/firmware/meson/meson_sm.h | 1 +
 2 files changed, 2 insertions(+)

diff --git a/drivers/firmware/meson/meson_sm.c b/drivers/firmware/meson/meson_sm.c
index 1d5b4d7..8cdd405 100644
--- a/drivers/firmware/meson/meson_sm.c
+++ b/drivers/firmware/meson/meson_sm.c
@@ -44,6 +44,7 @@ static const struct meson_sm_chip gxbb_chip = {
 		CMD(SM_EFUSE_WRITE,	0x82000031),
 		CMD(SM_EFUSE_USER_MAX,	0x82000033),
 		CMD(SM_GET_CHIP_ID,	0x82000044),
+		CMD(SM_A1_WATCHDOG_OPS,	0x82000086),
 		{ /* sentinel */ },
 	},
 };
diff --git a/include/linux/firmware/meson/meson_sm.h b/include/linux/firmware/meson/meson_sm.h
index 6669e2a..9ef1524 100644
--- a/include/linux/firmware/meson/meson_sm.h
+++ b/include/linux/firmware/meson/meson_sm.h
@@ -12,6 +12,7 @@ enum {
 	SM_EFUSE_WRITE,
 	SM_EFUSE_USER_MAX,
 	SM_GET_CHIP_ID,
+	SM_A1_WATCHDOG_OPS,
 };
 
 struct meson_sm_firmware;
-- 
2.7.4

[PATCH v6 2/5] firmware: meson_sm: populate platform device based on the child node

[Xingyu Chen]

The child node of secure-monitor cann't be populated as platform device
automatically during the kernel initialization phase, so we invoke
of_platform_default_populate() to do it.

Signed-off-by: Xingyu Chen <xingyu.chen@amlogic.com>
---
 drivers/firmware/meson/meson_sm.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/firmware/meson/meson_sm.c b/drivers/firmware/meson/meson_sm.c
index 8cdd405..d2b1e76 100644
--- a/drivers/firmware/meson/meson_sm.c
+++ b/drivers/firmware/meson/meson_sm.c
@@ -310,6 +310,8 @@ static int __init meson_sm_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, fw);
 
+	of_platform_default_populate(dev->of_node, NULL, dev);
+
 	pr_info("secure-monitor enabled\n");
 
 	if (sysfs_create_group(&pdev->dev.kobj, &meson_sm_sysfs_attr_group))
-- 
2.7.4

[PATCH v6 3/5] dt-bindings: watchdog: add new binding for meson secure watchdog

[Xingyu Chen]

The binding targets the Meson-A/C series compatible SoCs, in which the
watchdog registers are in secure world.

Signed-off-by: Xingyu Chen <xingyu.chen@amlogic.com>
---
 .../bindings/watchdog/amlogic,meson-sec-wdt.yaml   | 40 ++++++++++++++++++++++
 1 file changed, 40 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/watchdog/amlogic,meson-sec-wdt.yaml

diff --git a/Documentation/devicetree/bindings/watchdog/amlogic,meson-sec-wdt.yaml b/Documentation/devicetree/bindings/watchdog/amlogic,meson-sec-wdt.yaml
new file mode 100644
index 00000000..8e9d62a
--- /dev/null
+++ b/Documentation/devicetree/bindings/watchdog/amlogic,meson-sec-wdt.yaml
@@ -0,0 +1,40 @@
+# SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+# Copyright (c) 2019 Amlogic, Inc
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/power/amlogic,meson-sec-wdt.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: Amlogic Meson Secure Watchdog Timer
+
+maintainers:
+  - Xingyu Chen <xingyu.chen@amlogic.com>
+
+description: |+
+  Secure Watchdog Timer used in Meson-A/C series Compatible SoCs,
+  and its device node must be the child node of secure-monitor.
+
+properties:
+  compatible:
+    enum:
+      - amlogic,meson-sec-wdt
+
+  timeout-sec:
+    minimum: 1
+    maximum: 65
+    description:
+      Watchdog timeout values (in seconds)
+
+required:
+  - compatible
+
+examples:
+  - |
+    secure-monitor {
+        compatible = "amlogic,meson-gxbb-sm";
+
+        watchdog {
+            compatible = "amlogic,meson-sec-wdt";
+            timeout-sec = <60>;
+        };
+    };
-- 
2.7.4

[PATCH v6 4/5] watchdog: add meson secure watchdog driver

[Xingyu Chen]

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.

Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Xingyu Chen <xingyu.chen@amlogic.com>
---
 drivers/watchdog/Kconfig         |  16 ++++
 drivers/watchdog/Makefile        |   1 +
 drivers/watchdog/meson_sec_wdt.c | 185 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 202 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..493cbe8
--- /dev/null
+++ b/drivers/watchdog/meson_sec_wdt.c
@@ -0,0 +1,185 @@
+// 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 = dev_of_node(dev->parent);
+	if (!sm_np)
+		return -EINVAL;
+
+	data->fw = meson_sm_get(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

Re: [PATCH v6 3/5] dt-bindings: watchdog: add new binding for meson secure watchdog

[Rob Herring]

On Tue, 14 Jan 2020 11:45:25 +0800, Xingyu Chen wrote:
> The binding targets the Meson-A/C series compatible SoCs, in which the
> watchdog registers are in secure world.
> 
> Signed-off-by: Xingyu Chen <xingyu.chen@amlogic.com>
> ---
>  .../bindings/watchdog/amlogic,meson-sec-wdt.yaml   | 40 ++++++++++++++++++++++
>  1 file changed, 40 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/watchdog/amlogic,meson-sec-wdt.yaml
> 

Reviewed-by: Rob Herring <robh@kernel.org>