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@xxxxxxxxxxx>
---
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@xxxxxxxxxxx>
+ *
+ */
+#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
