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* [PATCH 0/4] add meson secure watchdog driver
@ 2019-10-12 10:05 Xingyu Chen
  2019-10-12 10:05 ` [PATCH 1/4] firmware: meson_sm: add new SMC ID support for accessing secure watchdog Xingyu Chen
                   ` (3 more replies)
  0 siblings, 4 replies; 9+ messages in thread
From: Xingyu Chen @ 2019-10-12 10:05 UTC (permalink / raw)
  To: Wim Van Sebroeck, Guenter Roeck, Kevin Hilman, Neil Armstrong
  Cc: Xingyu Chen, Rob Herring, Jerome Brunet, Qianggui Song,
	Jianxin Pan, Jian Hu, linux-watchdog, linux-amlogic,
	linux-arm-kernel, linux-kernel

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.

Xingyu Chen (4):
  firmware: meson_sm: add new SMC ID support for accessing secure
    watchdog
  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   |  34 ++++
 arch/arm64/boot/dts/amlogic/meson-a1.dtsi          |   6 +
 drivers/firmware/meson/meson_sm.c                  |   1 +
 drivers/watchdog/Kconfig                           |  16 ++
 drivers/watchdog/Makefile                          |   1 +
 drivers/watchdog/meson_sec_wdt.c                   | 205 +++++++++++++++++++++
 include/linux/firmware/meson/meson_sm.h            |   1 +
 7 files changed, 264 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


^ permalink raw reply	[flat|nested] 9+ messages in thread

* [PATCH 1/4] firmware: meson_sm: add new SMC ID support for accessing secure watchdog
  2019-10-12 10:05 [PATCH 0/4] add meson secure watchdog driver Xingyu Chen
@ 2019-10-12 10:05 ` Xingyu Chen
  2019-10-12 10:05 ` [PATCH 2/4] dt-bindings: watchdog: add new binding for meson " Xingyu Chen
                   ` (2 subsequent siblings)
  3 siblings, 0 replies; 9+ messages in thread
From: Xingyu Chen @ 2019-10-12 10:05 UTC (permalink / raw)
  To: Wim Van Sebroeck, Guenter Roeck, Kevin Hilman, Neil Armstrong
  Cc: Xingyu Chen, Rob Herring, Jerome Brunet, Qianggui Song,
	Jianxin Pan, Jian Hu, linux-watchdog, linux-amlogic,
	linux-arm-kernel, linux-kernel

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..46a44de 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_WATCHDOG_OPS,	0x82000086),
 		{ /* sentinel */ },
 	},
 };
diff --git a/include/linux/firmware/meson/meson_sm.h b/include/linux/firmware/meson/meson_sm.h
index 6669e2a..0934718 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_WATCHDOG_OPS,
 };
 
 struct meson_sm_firmware;
-- 
2.7.4


^ permalink raw reply	[flat|nested] 9+ messages in thread

* [PATCH 2/4] dt-bindings: watchdog: add new binding for meson secure watchdog
  2019-10-12 10:05 [PATCH 0/4] add meson secure watchdog driver Xingyu Chen
  2019-10-12 10:05 ` [PATCH 1/4] firmware: meson_sm: add new SMC ID support for accessing secure watchdog Xingyu Chen
@ 2019-10-12 10:05 ` " Xingyu Chen
  2019-10-12 10:05 ` [PATCH 3/4] watchdog: add meson secure watchdog driver Xingyu Chen
  2019-10-12 10:05 ` [PATCH 4/4] arm64: dts: a1: add secure watchdog controller Xingyu Chen
  3 siblings, 0 replies; 9+ messages in thread
From: Xingyu Chen @ 2019-10-12 10:05 UTC (permalink / raw)
  To: Wim Van Sebroeck, Guenter Roeck, Kevin Hilman, Neil Armstrong
  Cc: Xingyu Chen, Rob Herring, Jerome Brunet, Qianggui Song,
	Jianxin Pan, Jian Hu, linux-watchdog, linux-amlogic,
	linux-arm-kernel, linux-kernel, devicetree

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   | 34 ++++++++++++++++++++++
 1 file changed, 34 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..0bbc807
--- /dev/null
+++ b/Documentation/devicetree/bindings/watchdog/amlogic,meson-sec-wdt.yaml
@@ -0,0 +1,34 @@
+# 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
+
+properties:
+  compatible:
+    enum:
+      - amlogic,meson-sec-wdt
+
+  secure-monitor:
+    description: phandle to the secure-monitor node
+    $ref: /schemas/types.yaml#/definitions/phandle
+
+required:
+  - compatible
+  - secure-monitor
+
+examples:
+  - |
+    watchdog {
+          compatible = "amlogic,meson-sec-wdt";
+          secure-monitor = <&sm>;
+    };
-- 
2.7.4


^ permalink raw reply	[flat|nested] 9+ messages in thread

* [PATCH 3/4] watchdog: add meson secure watchdog driver
  2019-10-12 10:05 [PATCH 0/4] add meson secure watchdog driver Xingyu Chen
  2019-10-12 10:05 ` [PATCH 1/4] firmware: meson_sm: add new SMC ID support for accessing secure watchdog Xingyu Chen
  2019-10-12 10:05 ` [PATCH 2/4] dt-bindings: watchdog: add new binding for meson " Xingyu Chen
@ 2019-10-12 10:05 ` Xingyu Chen
  2019-10-12 14:29   ` Guenter Roeck
  2019-10-12 10:05 ` [PATCH 4/4] arm64: dts: a1: add secure watchdog controller Xingyu Chen
  3 siblings, 1 reply; 9+ messages in thread
From: Xingyu Chen @ 2019-10-12 10:05 UTC (permalink / raw)
  To: Wim Van Sebroeck, Guenter Roeck, Kevin Hilman, Neil Armstrong
  Cc: Xingyu Chen, Rob Herring, Jerome Brunet, Qianggui Song,
	Jianxin Pan, Jian Hu, linux-watchdog, linux-amlogic,
	linux-arm-kernel, linux-kernel

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 | 205 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 222 insertions(+)
 create mode 100644 drivers/watchdog/meson_sec_wdt.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 58e7c10..e6b0707 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 ARCH_MESON || COMPILE_TEST
+	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..2b5357c
--- /dev/null
+++ b/drivers/watchdog/meson_sec_wdt.c
@@ -0,0 +1,205 @@
+// 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)
+{
+	int ret;
+	struct meson_sec_wdt *data = watchdog_get_drvdata(wdt_dev);
+
+	ret = meson_sm_call(data->fw, SM_WATCHDOG_OPS, NULL,
+			    MESON_SIP_WDT_ENABLE, 0, 0, 0, 0);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int meson_sec_wdt_stop(struct watchdog_device *wdt_dev)
+{
+	int ret;
+	struct meson_sec_wdt *data = watchdog_get_drvdata(wdt_dev);
+
+	ret = meson_sm_call(data->fw, SM_WATCHDOG_OPS, NULL,
+			    MESON_SIP_WDT_DISABLE, 0, 0, 0, 0);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int meson_sec_wdt_ping(struct watchdog_device *wdt_dev)
+{
+	struct meson_sec_wdt *data = watchdog_get_drvdata(wdt_dev);
+
+	meson_sm_call(data->fw, SM_WATCHDOG_OPS, NULL,
+		      MESON_SIP_WDT_PING, 0, 0, 0, 0);
+
+	return 0;
+}
+
+static int meson_sec_wdt_set_timeout(struct watchdog_device *wdt_dev,
+				     unsigned int timeout)
+{
+	int ret;
+	struct meson_sec_wdt *data = watchdog_get_drvdata(wdt_dev);
+
+	wdt_dev->timeout = timeout;
+	meson_sec_wdt_ping(wdt_dev);
+
+	ret = meson_sm_call(data->fw, SM_WATCHDOG_OPS, NULL,
+			    MESON_SIP_WDT_SETTIMEOUT,
+			    wdt_dev->timeout, 0, 0, 0);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static unsigned int meson_sec_wdt_get_timeleft(struct watchdog_device *wdt_dev)
+{
+	int ret;
+	int timeleft;
+	struct meson_sec_wdt *data = watchdog_get_drvdata(wdt_dev);
+
+	ret = meson_sm_call(data->fw, SM_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))
+		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))
+		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_parse_phandle(pdev->dev.of_node, "secure-monitor", 0);
+	if (!sm_np) {
+		dev_err(&pdev->dev, "no secure-monitor node\n");
+		return -ENODEV;
+	}
+
+	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);
+
+	ret = meson_sm_call(data->fw, SM_WATCHDOG_OPS, NULL,
+			    MESON_SIP_WDT_INIT,
+			    data->wdt_dev.timeout, 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 BSD/GPL");
-- 
2.7.4


^ permalink raw reply	[flat|nested] 9+ messages in thread

* [PATCH 4/4] arm64: dts: a1: add secure watchdog controller
  2019-10-12 10:05 [PATCH 0/4] add meson secure watchdog driver Xingyu Chen
                   ` (2 preceding siblings ...)
  2019-10-12 10:05 ` [PATCH 3/4] watchdog: add meson secure watchdog driver Xingyu Chen
@ 2019-10-12 10:05 ` Xingyu Chen
  3 siblings, 0 replies; 9+ messages in thread
From: Xingyu Chen @ 2019-10-12 10:05 UTC (permalink / raw)
  To: Wim Van Sebroeck, Guenter Roeck, Kevin Hilman, Neil Armstrong
  Cc: Xingyu Chen, Rob Herring, Jerome Brunet, Qianggui Song,
	Jianxin Pan, Jian Hu, linux-watchdog, linux-amlogic,
	linux-arm-kernel, linux-kernel, devicetree

Enable secure watchdog controller for Meson-A1 SoC

Signed-off-by: Xingyu Chen <xingyu.chen@amlogic.com>
---
 arch/arm64/boot/dts/amlogic/meson-a1.dtsi | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/arm64/boot/dts/amlogic/meson-a1.dtsi b/arch/arm64/boot/dts/amlogic/meson-a1.dtsi
index 7210ad0..047c323 100644
--- a/arch/arm64/boot/dts/amlogic/meson-a1.dtsi
+++ b/arch/arm64/boot/dts/amlogic/meson-a1.dtsi
@@ -93,6 +93,12 @@
 				clock-names = "xtal", "pclk", "baud";
 				status = "disabled";
 			};
+
+			watchdog {
+				compatible = "amlogic,meson-sec-wdt";
+				secure-monitor = <&sm>;
+				status = "okay";
+			};
 		};
 
 		gic: interrupt-controller@ff901000 {
-- 
2.7.4


^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH 3/4] watchdog: add meson secure watchdog driver
  2019-10-12 10:05 ` [PATCH 3/4] watchdog: add meson secure watchdog driver Xingyu Chen
@ 2019-10-12 14:29   ` Guenter Roeck
  2019-10-14 11:42     ` Xingyu Chen
  0 siblings, 1 reply; 9+ messages in thread
From: Guenter Roeck @ 2019-10-12 14:29 UTC (permalink / raw)
  To: Xingyu Chen, Wim Van Sebroeck, Kevin Hilman, Neil Armstrong
  Cc: Rob Herring, Jerome Brunet, Qianggui Song, Jianxin Pan, Jian Hu,
	linux-watchdog, linux-amlogic, linux-arm-kernel, linux-kernel

On 10/12/19 3:05 AM, Xingyu Chen wrote:
> 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 | 205 +++++++++++++++++++++++++++++++++++++++
>   3 files changed, 222 insertions(+)
>   create mode 100644 drivers/watchdog/meson_sec_wdt.c
> 
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 58e7c10..e6b0707 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 ARCH_MESON || COMPILE_TEST

Did you try COMPILE_TEST (eg allmodconfig) on, say x86_64 ?
AFAICS the meson sm calls are only available if MESON_SM is
enabled, and that depends on both ARCH_MESON and ARM64_4K_PAGES.
This dependency is not expressed here, and neither is enabled
with COMPILE_TEST.

> +	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..2b5357c
> --- /dev/null
> +++ b/drivers/watchdog/meson_sec_wdt.c
> @@ -0,0 +1,205 @@
> +// 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)
> +{
> +	int ret;
> +	struct meson_sec_wdt *data = watchdog_get_drvdata(wdt_dev);
> +
> +	ret = meson_sm_call(data->fw, SM_WATCHDOG_OPS, NULL,
> +			    MESON_SIP_WDT_ENABLE, 0, 0, 0, 0); > +	if (ret)
> +		return ret;
> +
> +	return 0;

This is equivalent to
	return ret;
or even
	return meson_sm_call(...);

> +}
> +
> +static int meson_sec_wdt_stop(struct watchdog_device *wdt_dev)
> +{
> +	int ret;
> +	struct meson_sec_wdt *data = watchdog_get_drvdata(wdt_dev);
> +
> +	ret = meson_sm_call(data->fw, SM_WATCHDOG_OPS, NULL,
> +			    MESON_SIP_WDT_DISABLE, 0, 0, 0, 0);
> +	if (ret)
> +		return ret;
> +
> +	return 0;

Same as above.

> +}
> +
> +static int meson_sec_wdt_ping(struct watchdog_device *wdt_dev)
> +{
> +	struct meson_sec_wdt *data = watchdog_get_drvdata(wdt_dev);
> +
> +	meson_sm_call(data->fw, SM_WATCHDOG_OPS, NULL,
> +		      MESON_SIP_WDT_PING, 0, 0, 0, 0);
> +
> +	return 0;

Why ignore errors ?

> +}
> +
> +static int meson_sec_wdt_set_timeout(struct watchdog_device *wdt_dev,
> +				     unsigned int timeout)
> +{
> +	int ret;
> +	struct meson_sec_wdt *data = watchdog_get_drvdata(wdt_dev);
> +
> +	wdt_dev->timeout = timeout;
> +	meson_sec_wdt_ping(wdt_dev);
> +

Unconditionally ? Also, the core does that after setting the timeout.

> +	ret = meson_sm_call(data->fw, SM_WATCHDOG_OPS, NULL,
> +			    MESON_SIP_WDT_SETTIMEOUT,
> +			    wdt_dev->timeout, 0, 0, 0);
> +	if (ret)
> +		return ret;
> +
> +	return 0;

same as above.

> +}
> +
> +static unsigned int meson_sec_wdt_get_timeleft(struct watchdog_device *wdt_dev)
> +{
> +	int ret;
> +	int timeleft;
> +	struct meson_sec_wdt *data = watchdog_get_drvdata(wdt_dev);
> +
> +	ret = meson_sm_call(data->fw, SM_WATCHDOG_OPS, &timeleft,
> +			    MESON_SIP_WDT_GETTIMELEFT, 0, 0, 0, 0);
> +
> +	if (ret)
> +		return 0;

Really ? Why ? 0 is most definitely incorrect here.

> +
> +	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))
> +		meson_sec_wdt_start(&data->wdt_dev);

No error return ?

> +
> +	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))
> +		meson_sec_wdt_stop(&data->wdt_dev);

No error return ?

> +
> +	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_parse_phandle(pdev->dev.of_node, "secure-monitor", 0);
> +	if (!sm_np) {
> +		dev_err(&pdev->dev, "no secure-monitor node\n");
> +		return -ENODEV;

ENODEV is wrong here.

> +	}
> +
> +	data->fw = meson_sm_get(sm_np);
> +	of_node_put(sm_np);
> +	if (!data->fw)
> +		return -EPROBE_DEFER;

How do you know ?

> +
> +	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);
> +
No watchdog_init_timeout() ? Any special reason for not supporting
to set the timeout with a devicetree property ?

> +	ret = meson_sm_call(data->fw, SM_WATCHDOG_OPS, NULL,
> +			    MESON_SIP_WDT_INIT,
> +			    data->wdt_dev.timeout, 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 BSD/GPL");
> 
BSD or MIT ? This should match the license identifier.


^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH 3/4] watchdog: add meson secure watchdog driver
  2019-10-12 14:29   ` Guenter Roeck
@ 2019-10-14 11:42     ` Xingyu Chen
  2019-10-14 13:49       ` Guenter Roeck
  0 siblings, 1 reply; 9+ messages in thread
From: Xingyu Chen @ 2019-10-14 11:42 UTC (permalink / raw)
  To: Guenter Roeck, Wim Van Sebroeck, Kevin Hilman, Neil Armstrong
  Cc: Rob Herring, Jerome Brunet, Qianggui Song, Jianxin Pan, Jian Hu,
	linux-watchdog, linux-amlogic, linux-arm-kernel, linux-kernel

Hi, Guenter
Thanks for your review.

On 2019/10/12 22:29, Guenter Roeck wrote:
> On 10/12/19 3:05 AM, Xingyu Chen wrote:
>> 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 | 205 
>> +++++++++++++++++++++++++++++++++++++++
>>   3 files changed, 222 insertions(+)
>>   create mode 100644 drivers/watchdog/meson_sec_wdt.c
>>
>> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
>> index 58e7c10..e6b0707 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 ARCH_MESON || COMPILE_TEST
> 
> Did you try COMPILE_TEST (eg allmodconfig) on, say x86_64 ?
> AFAICS the meson sm calls are only available if MESON_SM is
> enabled, and that depends on both ARCH_MESON and ARM64_4K_PAGES.
> This dependency is not expressed here, and neither is enabled
> with COMPILE_TEST.Sorry, I have't done this kind of test before for this patchset. There
is a kernel build error which related to the current driver when i try 
to use allmodconfig with x86. I will fix it by adding "depends on 
MESON_SM" in next version.
> 
>> +    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..2b5357c
>> --- /dev/null
>> +++ b/drivers/watchdog/meson_sec_wdt.c
>> @@ -0,0 +1,205 @@
>> +// 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)
>> +{
>> +    int ret;
>> +    struct meson_sec_wdt *data = watchdog_get_drvdata(wdt_dev);
>> +
>> +    ret = meson_sm_call(data->fw, SM_WATCHDOG_OPS, NULL,
>> +                MESON_SIP_WDT_ENABLE, 0, 0, 0, 0); > +    if (ret)
>> +        return ret;
>> +
>> +    return 0;
> 
> This is equivalent to
>      return ret;
> or even
>      return meson_sm_call(...);
>I will fix it in next version.
>> +}
>> +
>> +static int meson_sec_wdt_stop(struct watchdog_device *wdt_dev)
>> +{
>> +    int ret;
>> +    struct meson_sec_wdt *data = watchdog_get_drvdata(wdt_dev);
>> +
>> +    ret = meson_sm_call(data->fw, SM_WATCHDOG_OPS, NULL,
>> +                MESON_SIP_WDT_DISABLE, 0, 0, 0, 0);
>> +    if (ret)
>> +        return ret;
>> +
>> +    return 0;
> 
> Same as above.
I will fix it in next version.
> 
>> +}
>> +
>> +static int meson_sec_wdt_ping(struct watchdog_device *wdt_dev)
>> +{
>> +    struct meson_sec_wdt *data = watchdog_get_drvdata(wdt_dev);
>> +
>> +    meson_sm_call(data->fw, SM_WATCHDOG_OPS, NULL,
>> +              MESON_SIP_WDT_PING, 0, 0, 0, 0);
>> +
>> +    return 0;
> 
> Why ignore errors ?
I will fix it as above.
> 
>> +}
>> +
>> +static int meson_sec_wdt_set_timeout(struct watchdog_device *wdt_dev,
>> +                     unsigned int timeout)
>> +{
>> +    int ret;
>> +    struct meson_sec_wdt *data = watchdog_get_drvdata(wdt_dev);
>> +
>> +    wdt_dev->timeout = timeout;
>> +    meson_sec_wdt_ping(wdt_dev);
>> +
> 
> Unconditionally ? Also, the core does that after setting the timeoutIt is used to avoid watchdog timer expire once the timeout is updated, 
and that the watchdog_ping from core not been invoked. If it is 
considered useless, i will remove it.

> 
>> +    ret = meson_sm_call(data->fw, SM_WATCHDOG_OPS, NULL,
>> +                MESON_SIP_WDT_SETTIMEOUT,
>> +                wdt_dev->timeout, 0, 0, 0);
>> +    if (ret)
>> +        return ret;
>> +
>> +    return 0;
> 
> same as above.
I will fix it in next version.
> 
>> +}
>> +
>> +static unsigned int meson_sec_wdt_get_timeleft(struct watchdog_device 
>> *wdt_dev)
>> +{
>> +    int ret;
>> +    int timeleft;
>> +    struct meson_sec_wdt *data = watchdog_get_drvdata(wdt_dev);
>> +
>> +    ret = meson_sm_call(data->fw, SM_WATCHDOG_OPS, &timeleft,
>> +                MESON_SIP_WDT_GETTIMELEFT, 0, 0, 0, 0);
>> +
>> +    if (ret)
>> +        return 0;
> 
> Really ? Why ? 0 is most definitely incorrect here.
I just want to return a invalid value after I failed to get valid 
timeleft. Could you tell me what is corrent value ?
> 
>> +
>> +    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))
>> +        meson_sec_wdt_start(&data->wdt_dev);
> 
> No error return ?
I will fix it in next version
> 
>> +
>> +    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))
>> +        meson_sec_wdt_stop(&data->wdt_dev);
> 
> No error return ?
same as above
> 
>> +
>> +    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_parse_phandle(pdev->dev.of_node, "secure-monitor", 0);
>> +    if (!sm_np) {
>> +        dev_err(&pdev->dev, "no secure-monitor node\n");
>> +        return -ENODEV;
> 
> ENODEV is wrong here.
I found some drivers use the ENODEV in this case, Eg:
- ./watchdog/ts4800_wdt.c -122
- ./nvmem/meson-efuse.c   -55
...

Could you tell me which error code is more suitable in this case ?

> 
>> +    }
>> +
>> +    data->fw = meson_sm_get(sm_np);
>> +    of_node_put(sm_np);
>> +    if (!data->fw)
>> +        return -EPROBE_DEFER;
> 
> How do you know ?
The fw pointer is static variable which is initialized to NULL. if it is 
equal to NULL, and indicate the meson_sm driver is not registered, then 
wdt driver use EPROBE_DEFER to defer probe.
> 
>> +
>> +    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);
>> +
> No watchdog_init_timeout() ? Any special reason for not supporting
> to set the timeout with a devicetree property ?
I want to keep consistency with previous meson watchdog driver.
as follows:
- meson_gxbb_wdt.c
- meson_wdt.c

> 
>> +    ret = meson_sm_call(data->fw, SM_WATCHDOG_OPS, NULL,
>> +                MESON_SIP_WDT_INIT,
>> +                data->wdt_dev.timeout, 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 BSD/GPL");
>>
> BSD or MIT ? This should match the license identifier.
MIT, I will fix it in next verson.
> 
> .
> 

^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH 3/4] watchdog: add meson secure watchdog driver
  2019-10-14 11:42     ` Xingyu Chen
@ 2019-10-14 13:49       ` Guenter Roeck
  2019-10-15  5:45         ` Xingyu Chen
  0 siblings, 1 reply; 9+ messages in thread
From: Guenter Roeck @ 2019-10-14 13:49 UTC (permalink / raw)
  To: Xingyu Chen, Wim Van Sebroeck, Kevin Hilman, Neil Armstrong
  Cc: Rob Herring, Jerome Brunet, Qianggui Song, Jianxin Pan, Jian Hu,
	linux-watchdog, linux-amlogic, linux-arm-kernel, linux-kernel

On 10/14/19 4:42 AM, Xingyu Chen wrote:
> Hi, Guenter
> Thanks for your review.
> 
> On 2019/10/12 22:29, Guenter Roeck wrote:
>> On 10/12/19 3:05 AM, Xingyu Chen wrote:
>>> 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 | 205 +++++++++++++++++++++++++++++++++++++++
>>>   3 files changed, 222 insertions(+)
>>>   create mode 100644 drivers/watchdog/meson_sec_wdt.c
>>>
>>> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
>>> index 58e7c10..e6b0707 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 ARCH_MESON || COMPILE_TEST
>>
>> Did you try COMPILE_TEST (eg allmodconfig) on, say x86_64 ?
>> AFAICS the meson sm calls are only available if MESON_SM is
>> enabled, and that depends on both ARCH_MESON and ARM64_4K_PAGES.
>> This dependency is not expressed here, and neither is enabled
>> with COMPILE_TEST.Sorry, I have't done this kind of test before for this patchset. There
> is a kernel build error which related to the current driver when i try to use allmodconfig with x86. I will fix it by adding "depends on MESON_SM" in next version.
>>
>>> +    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..2b5357c
>>> --- /dev/null
>>> +++ b/drivers/watchdog/meson_sec_wdt.c
>>> @@ -0,0 +1,205 @@
>>> +// 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)
>>> +{
>>> +    int ret;
>>> +    struct meson_sec_wdt *data = watchdog_get_drvdata(wdt_dev);
>>> +
>>> +    ret = meson_sm_call(data->fw, SM_WATCHDOG_OPS, NULL,
>>> +                MESON_SIP_WDT_ENABLE, 0, 0, 0, 0); > +    if (ret)
>>> +        return ret;
>>> +
>>> +    return 0;
>>
>> This is equivalent to
>>      return ret;
>> or even
>>      return meson_sm_call(...);
>> I will fix it in next version.
>>> +}
>>> +
>>> +static int meson_sec_wdt_stop(struct watchdog_device *wdt_dev)
>>> +{
>>> +    int ret;
>>> +    struct meson_sec_wdt *data = watchdog_get_drvdata(wdt_dev);
>>> +
>>> +    ret = meson_sm_call(data->fw, SM_WATCHDOG_OPS, NULL,
>>> +                MESON_SIP_WDT_DISABLE, 0, 0, 0, 0);
>>> +    if (ret)
>>> +        return ret;
>>> +
>>> +    return 0;
>>
>> Same as above.
> I will fix it in next version.
>>
>>> +}
>>> +
>>> +static int meson_sec_wdt_ping(struct watchdog_device *wdt_dev)
>>> +{
>>> +    struct meson_sec_wdt *data = watchdog_get_drvdata(wdt_dev);
>>> +
>>> +    meson_sm_call(data->fw, SM_WATCHDOG_OPS, NULL,
>>> +              MESON_SIP_WDT_PING, 0, 0, 0, 0);
>>> +
>>> +    return 0;
>>
>> Why ignore errors ?
> I will fix it as above.
>>
>>> +}
>>> +
>>> +static int meson_sec_wdt_set_timeout(struct watchdog_device *wdt_dev,
>>> +                     unsigned int timeout)
>>> +{
>>> +    int ret;
>>> +    struct meson_sec_wdt *data = watchdog_get_drvdata(wdt_dev);
>>> +
>>> +    wdt_dev->timeout = timeout;
>>> +    meson_sec_wdt_ping(wdt_dev);
>>> +
>>
>> Unconditionally ? Also, the core does that after setting the timeoutIt is used to avoid watchdog timer expire once the timeout is updated, 
> and that the watchdog_ping from core not been invoked. If it is considered useless, i will remove it.
> 

As mentioned, the core sends a ping immediately after the update.

>>
>>> +    ret = meson_sm_call(data->fw, SM_WATCHDOG_OPS, NULL,
>>> +                MESON_SIP_WDT_SETTIMEOUT,
>>> +                wdt_dev->timeout, 0, 0, 0);
>>> +    if (ret)
>>> +        return ret;
>>> +
>>> +    return 0;
>>
>> same as above.
> I will fix it in next version.
>>
>>> +}
>>> +
>>> +static unsigned int meson_sec_wdt_get_timeleft(struct watchdog_device *wdt_dev)
>>> +{
>>> +    int ret;
>>> +    int timeleft;
>>> +    struct meson_sec_wdt *data = watchdog_get_drvdata(wdt_dev);
>>> +
>>> +    ret = meson_sm_call(data->fw, SM_WATCHDOG_OPS, &timeleft,
>>> +                MESON_SIP_WDT_GETTIMELEFT, 0, 0, 0, 0);
>>> +
>>> +    if (ret)
>>> +        return 0;
>>
>> Really ? Why ? 0 is most definitely incorrect here.
> I just want to return a invalid value after I failed to get valid timeleft. Could you tell me what is corrent value ?

Why not return the error ?

>>
>>> +
>>> +    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))
>>> +        meson_sec_wdt_start(&data->wdt_dev);
>>
>> No error return ?
> I will fix it in next version
>>
>>> +
>>> +    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))
>>> +        meson_sec_wdt_stop(&data->wdt_dev);
>>
>> No error return ?
> same as above
>>
>>> +
>>> +    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_parse_phandle(pdev->dev.of_node, "secure-monitor", 0);
>>> +    if (!sm_np) {
>>> +        dev_err(&pdev->dev, "no secure-monitor node\n");
>>> +        return -ENODEV;
>>
>> ENODEV is wrong here.
> I found some drivers use the ENODEV in this case, Eg:
> - ./watchdog/ts4800_wdt.c -122
> - ./nvmem/meson-efuse.c   -55
> ...
> 
> Could you tell me which error code is more suitable in this case ?
> 

Yes, I understand, with Millions of LOC to choose from, you will
find examples for everything somewhere in the Linux kernel.
That doesn't mean it is a good idea.

The property is listed as mandatory, so EINVAL would probably be
most appropriate, unless DT handling proposes a different error code
in such situations.

>>
>>> +    }
>>> +
>>> +    data->fw = meson_sm_get(sm_np);
>>> +    of_node_put(sm_np);
>>> +    if (!data->fw)
>>> +        return -EPROBE_DEFER;
>>
>> How do you know ?
> The fw pointer is static variable which is initialized to NULL. if it is equal to NULL, and indicate the meson_sm driver is not registered, then wdt driver use EPROBE_DEFER to defer probe.
>>
>>> +
>>> +    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);
>>> +
>> No watchdog_init_timeout() ? Any special reason for not supporting
>> to set the timeout with a devicetree property ?
> I want to keep consistency with previous meson watchdog driver.
> as follows:
> - meson_gxbb_wdt.c
> - meson_wdt.c
> 

Yes, again, it is possible to find examples for pretty much everything
in the linux kernel. But, sure, as you wish.

Guenter

^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH 3/4] watchdog: add meson secure watchdog driver
  2019-10-14 13:49       ` Guenter Roeck
@ 2019-10-15  5:45         ` Xingyu Chen
  0 siblings, 0 replies; 9+ messages in thread
From: Xingyu Chen @ 2019-10-15  5:45 UTC (permalink / raw)
  To: Guenter Roeck, Wim Van Sebroeck, Kevin Hilman, Neil Armstrong
  Cc: Rob Herring, Jerome Brunet, Qianggui Song, Jianxin Pan, Jian Hu,
	linux-watchdog, linux-amlogic, linux-arm-kernel, linux-kernel

Hi, Guenter

On 2019/10/14 21:49, Guenter Roeck wrote:
> On 10/14/19 4:42 AM, Xingyu Chen wrote:
>> Hi, Guenter
>> Thanks for your review.
>>
>> On 2019/10/12 22:29, Guenter Roeck wrote:
>>> On 10/12/19 3:05 AM, Xingyu Chen wrote:
>>>> 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 | 205 
>>>> +++++++++++++++++++++++++++++++++++++++
>>>>   3 files changed, 222 insertions(+)
>>>>   create mode 100644 drivers/watchdog/meson_sec_wdt.c
>>>>
>>>> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
>>>> index 58e7c10..e6b0707 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 ARCH_MESON || COMPILE_TEST
>>>
>>> Did you try COMPILE_TEST (eg allmodconfig) on, say x86_64 ?
>>> AFAICS the meson sm calls are only available if MESON_SM is
>>> enabled, and that depends on both ARCH_MESON and ARM64_4K_PAGES.
>>> This dependency is not expressed here, and neither is enabled
>>> with COMPILE_TEST.Sorry, I have't done this kind of test before for 
>>> this patchset. There
>> is a kernel build error which related to the current driver when i try 
>> to use allmodconfig with x86. I will fix it by adding "depends on 
>> MESON_SM" in next version.
>>>
>>>> +    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..2b5357c
>>>> --- /dev/null
>>>> +++ b/drivers/watchdog/meson_sec_wdt.c
>>>> @@ -0,0 +1,205 @@
>>>> +// 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)
>>>> +{
>>>> +    int ret;
>>>> +    struct meson_sec_wdt *data = watchdog_get_drvdata(wdt_dev);
>>>> +
>>>> +    ret = meson_sm_call(data->fw, SM_WATCHDOG_OPS, NULL,
>>>> +                MESON_SIP_WDT_ENABLE, 0, 0, 0, 0); > +    if (ret)
>>>> +        return ret;
>>>> +
>>>> +    return 0;
>>>
>>> This is equivalent to
>>>      return ret;
>>> or even
>>>      return meson_sm_call(...);
>>> I will fix it in next version.
>>>> +}
>>>> +
>>>> +static int meson_sec_wdt_stop(struct watchdog_device *wdt_dev)
>>>> +{
>>>> +    int ret;
>>>> +    struct meson_sec_wdt *data = watchdog_get_drvdata(wdt_dev);
>>>> +
>>>> +    ret = meson_sm_call(data->fw, SM_WATCHDOG_OPS, NULL,
>>>> +                MESON_SIP_WDT_DISABLE, 0, 0, 0, 0);
>>>> +    if (ret)
>>>> +        return ret;
>>>> +
>>>> +    return 0;
>>>
>>> Same as above.
>> I will fix it in next version.
>>>
>>>> +}
>>>> +
>>>> +static int meson_sec_wdt_ping(struct watchdog_device *wdt_dev)
>>>> +{
>>>> +    struct meson_sec_wdt *data = watchdog_get_drvdata(wdt_dev);
>>>> +
>>>> +    meson_sm_call(data->fw, SM_WATCHDOG_OPS, NULL,
>>>> +              MESON_SIP_WDT_PING, 0, 0, 0, 0);
>>>> +
>>>> +    return 0;
>>>
>>> Why ignore errors ?
>> I will fix it as above.
>>>
>>>> +}
>>>> +
>>>> +static int meson_sec_wdt_set_timeout(struct watchdog_device *wdt_dev,
>>>> +                     unsigned int timeout)
>>>> +{
>>>> +    int ret;
>>>> +    struct meson_sec_wdt *data = watchdog_get_drvdata(wdt_dev);
>>>> +
>>>> +    wdt_dev->timeout = timeout;
>>>> +    meson_sec_wdt_ping(wdt_dev);
>>>> +
>>>
>>> Unconditionally ? Also, the core does that after setting the 
>>> timeoutIt is used to avoid watchdog timer expire once the timeout is 
>>> updated, 
>> and that the watchdog_ping from core not been invoked. If it is 
>> considered useless, i will remove it.
>>
> 
> As mentioned, the core sends a ping immediately after the update.
Ok, I will remove it in next version, Thanks
> 
>>>
>>>> +    ret = meson_sm_call(data->fw, SM_WATCHDOG_OPS, NULL,
>>>> +                MESON_SIP_WDT_SETTIMEOUT,
>>>> +                wdt_dev->timeout, 0, 0, 0);
>>>> +    if (ret)
>>>> +        return ret;
>>>> +
>>>> +    return 0;
>>>
>>> same as above.
>> I will fix it in next version.
>>>
>>>> +}
>>>> +
>>>> +static unsigned int meson_sec_wdt_get_timeleft(struct 
>>>> watchdog_device *wdt_dev)
>>>> +{
>>>> +    int ret;
>>>> +    int timeleft;
>>>> +    struct meson_sec_wdt *data = watchdog_get_drvdata(wdt_dev);
>>>> +
>>>> +    ret = meson_sm_call(data->fw, SM_WATCHDOG_OPS, &timeleft,
>>>> +                MESON_SIP_WDT_GETTIMELEFT, 0, 0, 0, 0);
>>>> +
>>>> +    if (ret)
>>>> +        return 0;
>>>
>>> Really ? Why ? 0 is most definitely incorrect here.
>> I just want to return a invalid value after I failed to get valid 
>> timeleft. Could you tell me what is corrent value ?
> 
> Why not return the error ?
I will return the error in next version, Thanks for your suggestion.
> 
>>>
>>>> +
>>>> +    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))
>>>> +        meson_sec_wdt_start(&data->wdt_dev);
>>>
>>> No error return ?
>> I will fix it in next version
>>>
>>>> +
>>>> +    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))
>>>> +        meson_sec_wdt_stop(&data->wdt_dev);
>>>
>>> No error return ?
>> same as above
>>>
>>>> +
>>>> +    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_parse_phandle(pdev->dev.of_node, "secure-monitor", 0);
>>>> +    if (!sm_np) {
>>>> +        dev_err(&pdev->dev, "no secure-monitor node\n");
>>>> +        return -ENODEV;
>>>
>>> ENODEV is wrong here.
>> I found some drivers use the ENODEV in this case, Eg:
>> - ./watchdog/ts4800_wdt.c -122
>> - ./nvmem/meson-efuse.c   -55
>> ...
>>
>> Could you tell me which error code is more suitable in this case ?
>>
> 
> Yes, I understand, with Millions of LOC to choose from, you will
> find examples for everything somewhere in the Linux kernel.
> That doesn't mean it is a good idea.
> 
> The property is listed as mandatory, so EINVAL would probably be
> most appropriate, unless DT handling proposes a different error code
> in such situations.
Thanks for your help, I will replace ENODEV with EINVAL in next version.
> 
>>>
>>>> +    }
>>>> +
>>>> +    data->fw = meson_sm_get(sm_np);
>>>> +    of_node_put(sm_np);
>>>> +    if (!data->fw)
>>>> +        return -EPROBE_DEFER;
>>>
>>> How do you know ?
>> The fw pointer is static variable which is initialized to NULL. if it 
>> is equal to NULL, and indicate the meson_sm driver is not registered, 
>> then wdt driver use EPROBE_DEFER to defer probe.
>>>
>>>> +
>>>> +    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);
>>>> +
>>> No watchdog_init_timeout() ? Any special reason for not supporting
>>> to set the timeout with a devicetree property ?
>> I want to keep consistency with previous meson watchdog driver.
>> as follows:
>> - meson_gxbb_wdt.c
>> - meson_wdt.c
>>
> 
> Yes, again, it is possible to find examples for pretty much everything
> in the linux kernel. But, sure, as you wish.
Thank you again.
> 
> Guenter
> 
> .
> 

^ permalink raw reply	[flat|nested] 9+ messages in thread

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Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-10-12 10:05 [PATCH 0/4] add meson secure watchdog driver Xingyu Chen
2019-10-12 10:05 ` [PATCH 1/4] firmware: meson_sm: add new SMC ID support for accessing secure watchdog Xingyu Chen
2019-10-12 10:05 ` [PATCH 2/4] dt-bindings: watchdog: add new binding for meson " Xingyu Chen
2019-10-12 10:05 ` [PATCH 3/4] watchdog: add meson secure watchdog driver Xingyu Chen
2019-10-12 14:29   ` Guenter Roeck
2019-10-14 11:42     ` Xingyu Chen
2019-10-14 13:49       ` Guenter Roeck
2019-10-15  5:45         ` Xingyu Chen
2019-10-12 10:05 ` [PATCH 4/4] arm64: dts: a1: add secure watchdog controller Xingyu Chen

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