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Thu, 20 Feb 2020 21:38:40 -0800 (PST) From: Evan Benn To: LKML Subject: [PATCH v2 2/2] watchdog: Add new mt8173_smc_wdt watchdog driver Date: Fri, 21 Feb 2020 16:38:02 +1100 Message-Id: <20200221163717.v2.2.I7c8247c29891a538f258cb47828d58acf22c95a2@changeid> X-Mailer: git-send-email 2.25.0.265.gbab2e86ba0-goog In-Reply-To: <20200221053802.70716-1-evanbenn@chromium.org> References: <20200221053802.70716-1-evanbenn@chromium.org> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200220_213842_531152_F7EACCE3 X-CRM114-Status: GOOD ( 19.48 ) X-Spam-Score: -0.2 (/) X-Spam-Report: SpamAssassin version 3.4.3 on bombadil.infradead.org summary: Content analysis details: (-0.2 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at https://www.dnswl.org/, no trust [2607:f8b0:4864:20:0:0:0:644 listed in] [list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature -0.0 DKIMWL_WL_HIGH DKIMwl.org - Whitelisted High sender X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Catalin Marinas , Mauro Carvalho Chehab , Leonard Crestez , Will Deacon , Rob Herring , Anson Huang , Marcin Juszkiewicz , Evan Benn , =?utf-8?b?Q2zDqW1lbnQgUMOpcm9u?= , Guenter Roeck , linux-watchdog@vger.kernel.org, linux-mediatek@lists.infradead.org, Jonathan Cameron , Matthias Brugger , Wim Van Sebroeck , linux-arm-kernel@lists.infradead.org, Greg Kroah-Hartman , Dinh Nguyen , Olof Johansson , jwerner@chromium.org, Shawn Guo , "David S. Miller" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org From: Julius Werner 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 Signed-off-by: Evan Benn --- 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/mt8173_smc_wdt.c | 160 ++++++++++++++++++++++++++++++ 5 files changed, 176 insertions(+) create mode 100644 drivers/watchdog/mt8173_smc_wdt.c diff --git a/MAINTAINERS b/MAINTAINERS index 59e8779363c12..94e295e16e128 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -1426,6 +1426,7 @@ M: Julius Werner R: Evan Benn S: Maintained F: devicetree/bindings/watchdog/mt8173,smc-wdt.yaml +F: drivers/watchdog/mt8173_smc_wdt.c ARM SMMU DRIVERS M: Will Deacon diff --git a/arch/arm64/configs/defconfig b/arch/arm64/configs/defconfig index b2f667307f829..11d94c9258b79 100644 --- a/arch/arm64/configs/defconfig +++ b/arch/arm64/configs/defconfig @@ -451,6 +451,7 @@ CONFIG_QCOM_TSENS=y CONFIG_UNIPHIER_THERMAL=y CONFIG_WATCHDOG=y CONFIG_ARM_SP805_WATCHDOG=y +CONFIG_MT8173_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 cec868f8db3f9..b4e55db7a4dcf 100644 --- a/drivers/watchdog/Kconfig +++ b/drivers/watchdog/Kconfig @@ -857,6 +857,19 @@ config DIGICOLOR_WATCHDOG To compile this driver as a module, choose M here: the module will be called digicolor_wdt. +config MT8173_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 2ee352bf3372d..d1381234892ef 100644 --- a/drivers/watchdog/Makefile +++ b/drivers/watchdog/Makefile @@ -92,6 +92,7 @@ obj-$(CONFIG_STM32_WATCHDOG) += stm32_iwdg.o obj-$(CONFIG_UNIPHIER_WATCHDOG) += uniphier_wdt.o obj-$(CONFIG_RTD119X_WATCHDOG) += rtd119x_wdt.o obj-$(CONFIG_SPRD_WATCHDOG) += sprd_wdt.o +obj-$(CONFIG_MT8173_SMC_WATCHDOG) += mt8173_smc_wdt.o obj-$(CONFIG_PM8916_WATCHDOG) += pm8916_wdt.o # X86 (i386 + ia64 + x86_64) Architecture diff --git a/drivers/watchdog/mt8173_smc_wdt.c b/drivers/watchdog/mt8173_smc_wdt.c new file mode 100644 index 0000000000000..681aa42c7d277 --- /dev/null +++ b/drivers/watchdog/mt8173_smc_wdt.c @@ -0,0 +1,160 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * ARM Secure Monitor Call watchdog driver + * + * Copyright 2020 Google LLC. + * Julius Werner + * Based on mtk_wdt.c + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define DRV_NAME "mt8173_smc_wdt" +#define DRV_VERSION "1.0" + +#define SMCWD_FUNC_ID 0x82003d06 + +enum smcwd_call { + SMCWD_INFO = 0, + SMCWD_SET_TIMEOUT = 1, + SMCWD_ENABLE = 2, + SMCWD_PET = 3, +}; + +static bool nowayout = WATCHDOG_NOWAYOUT; +static unsigned int timeout; + +static int smcwd_call(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(SMCWD_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(SMCWD_PET, 0, NULL); +} + +static int smcwd_set_timeout(struct watchdog_device *wdd, unsigned int timeout) +{ + int res; + + res = smcwd_call(SMCWD_SET_TIMEOUT, timeout, NULL); + if (!res) + wdd->timeout = timeout; + return res; +} + +static int smcwd_stop(struct watchdog_device *wdd) +{ + return smcwd_call(SMCWD_ENABLE, 0, NULL); +} + +static int smcwd_start(struct watchdog_device *wdd) +{ + return smcwd_call(SMCWD_ENABLE, 1, NULL); +} + +static const struct watchdog_info smcwd_info = { + .identity = DRV_NAME, + .options = WDIOF_SETTIMEOUT | + WDIOF_KEEPALIVEPING | + WDIOF_MAGICCLOSE, +}; + +static const struct watchdog_ops smcwd_ops = { + .start = smcwd_start, + .stop = smcwd_stop, + .ping = smcwd_ping, + .set_timeout = smcwd_set_timeout, +}; + +static int smcwd_probe(struct platform_device *pdev) +{ + struct watchdog_device *wdd; + int err; + struct arm_smccc_res res; + + err = smcwd_call(SMCWD_INFO, 0, &res); + if (err < 0) + return err; + + wdd = devm_kzalloc(&pdev->dev, sizeof(*wdd), GFP_KERNEL); + if (!wdd) + return -ENOMEM; + + platform_set_drvdata(pdev, wdd); + + wdd->info = &smcwd_info; + wdd->ops = &smcwd_ops; + wdd->timeout = res.a2; + wdd->max_timeout = res.a2; + wdd->min_timeout = res.a1; + wdd->parent = &pdev->dev; + + watchdog_stop_on_reboot(wdd); + watchdog_stop_on_unregister(wdd); + watchdog_set_nowayout(wdd, nowayout); + watchdog_init_timeout(wdd, timeout, &pdev->dev); + err = smcwd_set_timeout(wdd, wdd->timeout); + if (err) + return err; + + err = devm_watchdog_register_device(&pdev->dev, wdd); + if (err) + return err; + + dev_info(&pdev->dev, "Watchdog registered (timeout=%d sec, nowayout=%d)\n", + wdd->timeout, nowayout); + + return 0; +} + +static const struct of_device_id smcwd_dt_ids[] = { + { .compatible = "mt8173,smc-wdt" }, + {} +}; +MODULE_DEVICE_TABLE(of, smcwd_dt_ids); + +static struct platform_driver smcwd_driver = { + .probe = smcwd_probe, + .driver = { + .name = DRV_NAME, + .of_match_table = smcwd_dt_ids, + }, +}; + +module_platform_driver(smcwd_driver); + +module_param(timeout, uint, 0); +MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds"); + +module_param(nowayout, bool, 0); +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" + __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Julius Werner "); +MODULE_DESCRIPTION("ARM Secure Monitor Call Watchdog Driver"); +MODULE_VERSION(DRV_VERSION);