From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BE6D0CA9EB9 for ; Mon, 21 Oct 2019 08:03:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 88BD72089C for ; Mon, 21 Oct 2019 08:03:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727516AbfJUIDA (ORCPT ); Mon, 21 Oct 2019 04:03:00 -0400 Received: from mail-sz.amlogic.com ([211.162.65.117]:54755 "EHLO mail-sz.amlogic.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725972AbfJUIC7 (ORCPT ); Mon, 21 Oct 2019 04:02:59 -0400 Received: from [10.28.19.63] (10.28.19.63) by mail-sz.amlogic.com (10.28.11.5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1591.10; Mon, 21 Oct 2019 16:03:07 +0800 Subject: Re: [PATCH v2 3/4] watchdog: add meson secure watchdog driver To: Guenter Roeck , Wim Van Sebroeck , Kevin Hilman , Neil Armstrong CC: Rob Herring , Jerome Brunet , Qianggui Song , Jianxin Pan , Jian Hu , , , , References: <1571387622-35132-1-git-send-email-xingyu.chen@amlogic.com> <1571387622-35132-4-git-send-email-xingyu.chen@amlogic.com> <7397f6db-1dc8-3abd-41ff-2e47323c7ffa@roeck-us.net> From: Xingyu Chen Message-ID: Date: Mon, 21 Oct 2019 16:03:07 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <7397f6db-1dc8-3abd-41ff-2e47323c7ffa@roeck-us.net> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 8bit X-Originating-IP: [10.28.19.63] X-ClientProxiedBy: mail-sz.amlogic.com (10.28.11.5) To mail-sz.amlogic.com (10.28.11.5) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Guenter On 2019/10/21 0:56, Guenter Roeck wrote: > On 10/18/19 1:33 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 >> --- >>   drivers/watchdog/Kconfig         |  17 ++++ >>   drivers/watchdog/Makefile        |   1 + >>   drivers/watchdog/meson_sec_wdt.c | 187 >> +++++++++++++++++++++++++++++++++++++++ >>   3 files changed, 205 insertions(+) >>   create mode 100644 drivers/watchdog/meson_sec_wdt.c >> >> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig >> index 58e7c10..e84be42 100644 >> --- a/drivers/watchdog/Kconfig >> +++ b/drivers/watchdog/Kconfig >> @@ -826,6 +826,23 @@ 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 >> +    depends on ARCH_MESON || COMPILE_TEST > > This dependency is pointless. MESON_SM already depends on ARCH_MESON, > thus specifying "COMPILE_TEST" here adds no value but only > creates confusion. Thanks for your analysis, perhaps i should remove the line below. - depends on ARCH_MESON || COMPILE_TEST Is it ok to modify code above like this ? > >> +    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..86bd87c >> --- /dev/null >> +++ b/drivers/watchdog/meson_sec_wdt.c >> @@ -0,0 +1,187 @@ >> +// SPDX-License-Identifier: (GPL-2.0+ OR MIT) >> +/* >> + * Copyright (c) 2019 Amlogic, Inc. All rights reserved. >> + * Author: Xingyu Chen >> + * >> + */ >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> + >> +#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_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_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_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_WATCHDOG_OPS, NULL, >> +                 MESON_SIP_WDT_SETTIMEOUT, >> +                 wdt_dev->timeout, 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_WATCHDOG_OPS, &timeleft, >> +                MESON_SIP_WDT_GETTIMELEFT, 0, 0, 0, 0); >> + >> +    if (ret) >> +        return ret; > > Meh, that doesn't work. I just realized that the return type is unsigned, > so returning a negative error code is pointless. Guess we'll have to > live with returning 0 in this case after all. I wonder if we should > fix the API and return an integer (with negative error code), but that > is a different question. Thanks for your review. IMO, if returning an integer, and the value which copy to user buf should be formatted with %d instead of %u (see timeleft_show), it will cause the max value of timeleft is reduced from 4294967295 to 2147483647. but i'am not sure whether it will bring risk. So i also think returning 0 may be better in this case. > > Sorry for the confusion - I should have noticed that before. > >> + >> +    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 = of_parse_phandle(pdev->dev.of_node, "secure-monitor", 0); >> +    if (!sm_np) { >> +        dev_err(&pdev->dev, "no secure-monitor node\n"); >> +        return -EINVAL; >> +    } >> + >> +    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 "); >> +MODULE_DESCRIPTION("Amlogic Secure Watchdog Timer Driver"); >> +MODULE_LICENSE("Dual MIT/GPL"); >> > > . >