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Thu, 03 Oct 2019 06:49:07 -0700 (PDT) Subject: Re: [PATCH v2 2/4] watchdog: mtk_wdt: mt8183: Add reset controller To: Jiaxin Yu , broonie@kernel.org, mark.rutland@arm.com, robh+dt@kernel.org, wim@linux-watchdog.org References: <1569580317-21181-1-git-send-email-jiaxin.yu@mediatek.com> <1569580317-21181-3-git-send-email-jiaxin.yu@mediatek.com> From: Guenter Roeck Message-ID: Date: Thu, 3 Oct 2019 06:49:05 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <1569580317-21181-3-git-send-email-jiaxin.yu@mediatek.com> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191003_064910_890442_D599DE46 X-CRM114-Status: GOOD ( 24.76 ) 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: alsa-devel@alsa-project.org, yong.liang@mediatek.com, lgirdwood@gmail.com, perex@perex.cz, tzungbi@google.com, linux-mediatek@lists.infradead.org, eason.yen@mediatek.com, linux-arm-kernel@lists.infradead.org Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 9/27/19 3:31 AM, Jiaxin Yu wrote: > From: "yong.liang" > > Provide assert/deassert/reset API in watchdog driver. > Register reset controller for toprgu device in watchdog probe. > > Signed-off-by: yong.liang > --- > drivers/watchdog/Kconfig | 1 + > drivers/watchdog/mtk_wdt.c | 110 ++++++++++++++++++++++++++++++++++++- > 2 files changed, 110 insertions(+), 1 deletion(-) > > diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig > index 2e07caab9db2..629249fe5305 100644 > --- a/drivers/watchdog/Kconfig > +++ b/drivers/watchdog/Kconfig > @@ -717,6 +717,7 @@ config MEDIATEK_WATCHDOG > tristate "Mediatek SoCs watchdog support" > depends on ARCH_MEDIATEK || COMPILE_TEST > select WATCHDOG_CORE > + select RESET_CONTROLLER > help > Say Y here to include support for the watchdog timer > in Mediatek SoCs. > diff --git a/drivers/watchdog/mtk_wdt.c b/drivers/watchdog/mtk_wdt.c > index 9c3d0033260d..660fb0e48d8e 100644 > --- a/drivers/watchdog/mtk_wdt.c > +++ b/drivers/watchdog/mtk_wdt.c > @@ -20,6 +20,10 @@ > #include > #include > #include > +#include > +#include > +#include > +#include > > #define WDT_MAX_TIMEOUT 31 > #define WDT_MIN_TIMEOUT 1 > @@ -44,17 +48,113 @@ > #define WDT_SWRST 0x14 > #define WDT_SWRST_KEY 0x1209 > > +#define WDT_SWSYSRST 0x18U > +#define WDT_SWSYS_RST_KEY 0x88000000 > + > #define DRV_NAME "mtk-wdt" > #define DRV_VERSION "1.0" > > static bool nowayout = WATCHDOG_NOWAYOUT; > static unsigned int timeout; > > +struct toprgu_reset { > + spinlock_t lock; /* Protects reset_controller access */ > + void __iomem *toprgu_swrst_base; > + int regofs; > + struct reset_controller_dev rcdev; > +}; > + > struct mtk_wdt_dev { > struct watchdog_device wdt_dev; > void __iomem *wdt_base; > + struct toprgu_reset reset_controller; > + const struct mtk_wdt_compatible *dev_comp; "dev_comp" suggests that this would be a device name. In practice, the only value there is sw_rst_num, and the value is only used in toprgu_register_reset_controller(). Might as well pass it as argument and drop this pointer. > +}; > + > +struct mtk_wdt_compatible { > + int sw_rst_num; > +}; > + "compatible" is an odd name for this structure. I would suggest to select a more common name such as "mtk_wdt_data". > +static int toprgu_reset_assert(struct reset_controller_dev *rcdev, > + unsigned long id) > +{ > + unsigned int tmp; > + unsigned long flags; > + struct toprgu_reset *data = container_of(rcdev, > + struct toprgu_reset, rcdev); > + > + spin_lock_irqsave(&data->lock, flags); > + > + tmp = __raw_readl(data->toprgu_swrst_base + data->regofs); > + tmp |= BIT(id); > + tmp |= WDT_SWSYS_RST_KEY; > + writel(tmp, data->toprgu_swrst_base + data->regofs); > + > + spin_unlock_irqrestore(&data->lock, flags); > + > + return 0; > +} > + > +static int toprgu_reset_deassert(struct reset_controller_dev *rcdev, > + unsigned long id) > +{ > + unsigned int tmp; > + unsigned long flags; > + struct toprgu_reset *data = container_of(rcdev, > + struct toprgu_reset, rcdev); > + > + spin_lock_irqsave(&data->lock, flags); > + > + tmp = __raw_readl(data->toprgu_swrst_base + data->regofs); > + tmp &= ~BIT(id); > + tmp |= WDT_SWSYS_RST_KEY; > + writel(tmp, data->toprgu_swrst_base + data->regofs); > + > + spin_unlock_irqrestore(&data->lock, flags); > + > + return 0; > +} > + > +static int toprgu_reset(struct reset_controller_dev *rcdev, > + unsigned long id) > +{ > + int ret; > + > + ret = toprgu_reset_assert(rcdev, id); > + if (ret) > + return ret; > + > + return toprgu_reset_deassert(rcdev, id); Unless there is additional synchronization elsewhere, parallel calls to the -> assert, and ->reset callbacks may result in the reset being deasserted while at least one caller (the one who called the ->assert function) believes that it is still asserted. [ ... and if there _is_ additional synchronization elsewhere, the local spinlock would be unnecessary ] > +} > + > +static struct reset_control_ops toprgu_reset_ops = { > + .assert = toprgu_reset_assert, > + .deassert = toprgu_reset_deassert, > + .reset = toprgu_reset, > }; > > +static void toprgu_register_reset_controller(struct platform_device *pdev, > + int regofs) Since there is only one well defined offset, it seems unnecessary to pass regofs as parameter. > +{ > + int ret; > + struct mtk_wdt_dev *mtk_wdt = platform_get_drvdata(pdev); > + > + spin_lock_init(&mtk_wdt->reset_controller.lock); > + > + mtk_wdt->dev_comp = of_device_get_match_data(&pdev->dev); Duplicate, and not really needed. Just pass sw_rst_num as argument. > + mtk_wdt->reset_controller.toprgu_swrst_base = mtk_wdt->wdt_base; > + mtk_wdt->reset_controller.regofs = regofs; > + mtk_wdt->reset_controller.rcdev.owner = THIS_MODULE; > + mtk_wdt->reset_controller.rcdev.nr_resets = > + mtk_wdt->dev_comp->sw_rst_num; > + mtk_wdt->reset_controller.rcdev.ops = &toprgu_reset_ops; > + mtk_wdt->reset_controller.rcdev.of_node = pdev->dev.of_node; > + ret = reset_controller_register(&mtk_wdt->reset_controller.rcdev); > + if (ret != 0) > + dev_err(&pdev->dev, > + "couldn't register wdt reset controller: %d\n", ret); > +} > + > static int mtk_wdt_restart(struct watchdog_device *wdt_dev, > unsigned long action, void *data) > { > @@ -187,9 +287,12 @@ static int mtk_wdt_probe(struct platform_device *pdev) > if (unlikely(err)) > return err; > > - dev_info(dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)\n", > + dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)\n", > mtk_wdt->wdt_dev.timeout, nowayout); > > + mtk_wdt->dev_comp = of_device_get_match_data(&pdev->dev); > + if (mtk_wdt->dev_comp) > + toprgu_register_reset_controller(pdev, WDT_SWSYSRST); > return 0; > } > > @@ -217,7 +320,12 @@ static int mtk_wdt_resume(struct device *dev) > } > #endif > > +static const struct mtk_wdt_compatible mt8183_compat = { > + .sw_rst_num = 18, Please no such magic numbers. This should be a define in an include file. > +}; > + > static const struct of_device_id mtk_wdt_dt_ids[] = { > + { .compatible = "mediatek,mt8183-wdt", .data = &mt8183_compat }, > { .compatible = "mediatek,mt6589-wdt" }, > { /* sentinel */ } > }; > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel