Messages in this thread | | | Subject | Re: [PATCH v2 2/2] watchdog: Add new arm_smc_wdt watchdog driver | From | Xingyu Chen <> | Date | Wed, 22 Apr 2020 12:02:47 +0800 |
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Hi,Evan
On 2020/4/21 19:05, Evan Benn wrote: > From: Julius Werner <jwerner@chromium.org> > > This patch adds a watchdog driver that can be used on ARM systems > with the appropriate watchdog implemented in Secure Monitor firmware. > The driver communicates with firmware via a Secure Monitor Call. > This may be useful for platforms using TrustZone that want > the Secure Monitor firmware to have the final control over the watchdog. > > This is implemented on mt8173 chromebook devices oak, elm and hana in > arm trusted firmware file plat/mediatek/mt8173/drivers/wdt/wdt.c. > > Signed-off-by: Julius Werner <jwerner@chromium.org> > Signed-off-by: Evan Benn <evanbenn@chromium.org> > Reviewed-by: Guenter Roeck <linux@roeck-us.net> > > --- > > Changes in v4: > - Get smc-id from of property > - Return a1 instead of a0 in timeleft > > Changes in v3: > - Add optional get_timeleft op > - change name to arm_smc_wdt > > Changes in v2: > - use watchdog_stop_on_reboot > - use watchdog_stop_on_unregister > - use devm_watchdog_register_device > - remove smcwd_shutdown, smcwd_remove > - change error codes > > MAINTAINERS | 1 + > arch/arm64/configs/defconfig | 1 + > drivers/watchdog/Kconfig | 13 +++ > drivers/watchdog/Makefile | 1 + > drivers/watchdog/arm_smc_wdt.c | 194 +++++++++++++++++++++++++++++++++ > 5 files changed, 210 insertions(+) > create mode 100644 drivers/watchdog/arm_smc_wdt.c > > diff --git a/MAINTAINERS b/MAINTAINERS > index 0f2b39767bfa9..2b782bbff200a 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -1462,6 +1462,7 @@ M: Julius Werner <jwerner@chromium.org> > R: Evan Benn <evanbenn@chromium.org> > S: Maintained > F: devicetree/bindings/watchdog/arm-smc-wdt.yaml > +F: drivers/watchdog/arm_smc_wdt.c > > ARM SMMU DRIVERS > M: Will Deacon <will@kernel.org> > diff --git a/arch/arm64/configs/defconfig b/arch/arm64/configs/defconfig > index 24e534d850454..0619df80f7575 100644 > --- a/arch/arm64/configs/defconfig > +++ b/arch/arm64/configs/defconfig > @@ -513,6 +513,7 @@ CONFIG_UNIPHIER_THERMAL=y > CONFIG_WATCHDOG=y > CONFIG_ARM_SP805_WATCHDOG=y > CONFIG_ARM_SBSA_WATCHDOG=y > +CONFIG_ARM_SMC_WATCHDOG=y > CONFIG_S3C2410_WATCHDOG=y > CONFIG_DW_WATCHDOG=y > CONFIG_SUNXI_WATCHDOG=m > diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig > index 0663c604bd642..c440b576d23bf 100644 > --- a/drivers/watchdog/Kconfig > +++ b/drivers/watchdog/Kconfig > @@ -867,6 +867,19 @@ config DIGICOLOR_WATCHDOG > To compile this driver as a module, choose M here: the > module will be called digicolor_wdt. > > +config ARM_SMC_WATCHDOG > + tristate "ARM Secure Monitor Call based watchdog support" > + depends on ARM || ARM64 > + depends on OF > + depends on HAVE_ARM_SMCCC > + select WATCHDOG_CORE > + help > + Say Y here to include support for a watchdog timer > + implemented by the EL3 Secure Monitor on ARM platforms. > + Requires firmware support. > + To compile this driver as a module, choose M here: the > + module will be called arm_smc_wdt. > + > config LPC18XX_WATCHDOG > tristate "LPC18xx/43xx Watchdog" > depends on ARCH_LPC18XX || COMPILE_TEST > diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile > index 6de2e4ceef190..97bed1d3d97cb 100644 > --- a/drivers/watchdog/Makefile > +++ b/drivers/watchdog/Makefile > @@ -94,6 +94,7 @@ obj-$(CONFIG_UNIPHIER_WATCHDOG) += uniphier_wdt.o > obj-$(CONFIG_RTD119X_WATCHDOG) += rtd119x_wdt.o > obj-$(CONFIG_SPRD_WATCHDOG) += sprd_wdt.o > obj-$(CONFIG_PM8916_WATCHDOG) += pm8916_wdt.o > +obj-$(CONFIG_ARM_SMC_WATCHDOG) += arm_smc_wdt.o > > # X86 (i386 + ia64 + x86_64) Architecture > obj-$(CONFIG_ACQUIRE_WDT) += acquirewdt.o > diff --git a/drivers/watchdog/arm_smc_wdt.c b/drivers/watchdog/arm_smc_wdt.c > new file mode 100644 > index 0000000000000..29d2573b2ca11 > --- /dev/null > +++ b/drivers/watchdog/arm_smc_wdt.c > @@ -0,0 +1,194 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * ARM Secure Monitor Call watchdog driver > + * > + * Copyright 2020 Google LLC. > + * Julius Werner <jwerner@chromium.org> > + * Based on mtk_wdt.c > + */ > + > +#include <linux/arm-smccc.h> > +#include <linux/err.h> > +#include <linux/module.h> > +#include <linux/moduleparam.h> > +#include <linux/of.h> > +#include <linux/platform_device.h> > +#include <linux/types.h> > +#include <linux/watchdog.h> > +#include <uapi/linux/psci.h> > + > +#define DRV_NAME "arm_smc_wdt" > +#define DRV_VERSION "1.0" > + > +#define get_smc_func_id(wdd) (*(u32 *)watchdog_get_drvdata(wdd)) > +enum smcwd_call { > + SMCWD_INIT = 0, > + SMCWD_SET_TIMEOUT = 1, > + SMCWD_ENABLE = 2, > + SMCWD_PET = 3, > + SMCWD_GET_TIMELEFT = 4, > +}; > + > +static bool nowayout = WATCHDOG_NOWAYOUT; > +static unsigned int timeout; > + > +static int smcwd_call(unsigned long smc_func_id, enum smcwd_call call, > + unsigned long arg, struct arm_smccc_res *res) > +{ > + struct arm_smccc_res local_res; > + > + if (!res) > + res = &local_res; > + > + arm_smccc_smc(smc_func_id, call, arg, 0, 0, 0, 0, 0, res); > + > + if (res->a0 == PSCI_RET_NOT_SUPPORTED) > + return -ENODEV; > + if (res->a0 == PSCI_RET_INVALID_PARAMS) > + return -EINVAL; > + if (res->a0 != PSCI_RET_SUCCESS) > + return -EIO; > + return 0; > +} > + > +static int smcwd_ping(struct watchdog_device *wdd) > +{ > + return smcwd_call(get_smc_func_id(wdd), SMCWD_PET, 0, NULL); > +} > + > +static unsigned int smcwd_get_timeleft(struct watchdog_device *wdd) > +{ > + struct arm_smccc_res res; > + > + smcwd_call(get_smc_func_id(wdd), SMCWD_GET_TIMELEFT, 0, &res); > + return res.a1;It should return 0 when the smcwd_call return error according to Guenter's suggestion at [0]
[0]: https://patchwork.kernel.org/patch/11197781/
Thanks. > + > +static int smcwd_set_timeout(struct watchdog_device *wdd, unsigned int timeout) > +{ > + int res; > + > + res = smcwd_call(get_smc_func_id(wdd), SMCWD_SET_TIMEOUT, timeout, > + NULL); > + if (!res) > + wdd->timeout = timeout; > + return res; > +} > + > +static int smcwd_stop(struct watchdog_device *wdd) > +{ > + return smcwd_call(get_smc_func_id(wdd), SMCWD_ENABLE, 0, NULL); > +} > + [...] > +MODULE_LICENSE("GPL"); > +MODULE_AUTHOR("Julius Werner <jwerner@chromium.org>"); > +MODULE_DESCRIPTION("ARM Secure Monitor Call Watchdog Driver"); > +MODULE_VERSION(DRV_VERSION); >
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