From patchwork Mon May 27 16:14:28 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Herve Codina X-Patchwork-Id: 13675618 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id CD355C25B74 for ; Mon, 27 May 2024 16:15:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=8Hql+etGSPdSQ3Ymb/cs4va0nSAyLw/VCzUtHqpF6WQ=; b=CHfQL/fgj2+J17 MRLVWgRVwyTdEpG0Z3m4h19f55e8wl58fHaAfMZsNGjWm+/MbXhVpNGLXHD+JRq7rSyoIs288D1DP XJhO8GvPiDz6WRoCVCr2+hqbkfytr9QG6Lh6PiV281AH0A5l9VNYcBa1ORZBsFE1ZUdX9WfnKghrz H8yDsIDX+Px+bcYQsQyWOfdTw382ZkhjkhQjkzkFdBdq/rIEchFm7zLSA+6zHbalbOaysOcbendrZ 1bcOMhcqpC24ldobyhhhTSL92hiZoufbAAAK8uzLBMM96GujUBrfySieJdvy2rCu0dBzGfswAgFiF hp1A7txwBJbJHbk6a9Dw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sBd06-0000000FmTy-3P8M; Mon, 27 May 2024 16:15:06 +0000 Received: from relay9-d.mail.gandi.net ([2001:4b98:dc4:8::229]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1sBd03-0000000FmQs-0Zm2 for linux-arm-kernel@lists.infradead.org; Mon, 27 May 2024 16:15:04 +0000 Received: by mail.gandi.net (Postfix) with ESMTPA id 6E42AFF811; Mon, 27 May 2024 16:14:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1716826500; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=W9+p1hma003opriOOEox9fT6iYMjtITIcW1ZIQ2QLNo=; b=UbbkYHxYIA3ApPt5oZI7rO4HRwWoAo+RNwHf495UokGST04QM/XPmwZtNfGcvXqNkTLLfv zPUvOe+3SPZsP9KT2IJxAesVe4FI9LV4C2BZTsojIVpNNUeFoesg2zWL8OJEA8+nRMAOHN K+llDN/wjyKrld3B3chDtl9+p+esUWB+dB8aE9FtPOBBFiQg0um64VbuBdlxOWQtqvk3OM W0JAOMp5UrAlcivoZaqFJ2Ggh8DZV8bwlkDnUzSnTShUs503r9tGo7Of+ahmFZI3fGyWJG U5aa5lsr0s8+nuyELHEYKPojqVP9Am8/bPDFC0Q/FPlAZ32lf/kjwEoYKm4y8A== From: Herve Codina To: Simon Horman , Sai Krishna Gajula , Herve Codina , Thomas Gleixner , Rob Herring , Krzysztof Kozlowski , Conor Dooley , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Lee Jones , Arnd Bergmann , Horatiu Vultur , UNGLinuxDriver@microchip.com, Andrew Lunn , Heiner Kallweit , Russell King , Saravana Kannan , Bjorn Helgaas , Philipp Zabel , Lars Povlsen , Steen Hegelund , Daniel Machon , Alexandre Belloni Cc: linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, netdev@vger.kernel.org, linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Allan Nielsen , Steen Hegelund , Luca Ceresoli , Thomas Petazzoni , =?utf-8?b?Q2zDqW1lbnQgTMOp?= =?utf-8?b?Z2Vy?= Subject: [PATCH v2 01/19] mfd: syscon: Add reference counting and device managed support Date: Mon, 27 May 2024 18:14:28 +0200 Message-ID: <20240527161450.326615-2-herve.codina@bootlin.com> X-Mailer: git-send-email 2.45.0 In-Reply-To: <20240527161450.326615-1-herve.codina@bootlin.com> References: <20240527161450.326615-1-herve.codina@bootlin.com> MIME-Version: 1.0 X-GND-Sasl: herve.codina@bootlin.com X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240527_091503_552459_FB7A63F0 X-CRM114-Status: GOOD ( 23.77 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Clément Léger Syscon releasing is not supported. Without release function, unbinding a driver that uses syscon whether explicitly or due to a module removal left the used syscon in a in-use state. For instance a syscon_node_to_regmap() call from a consumer retrieve a syscon regmap instance. Internally, syscon_node_to_regmap() can create syscon instance and add it to the existing syscon list. No API is available to release this syscon instance, remove it from the list and free it when it is not used anymore. Introduce reference counting in syscon in order to keep track of syscon usage using syscon_{get,put}() and add a device managed version of syscon_regmap_lookup_by_phandle(), to automatically release the syscon instance on the consumer removal. Signed-off-by: Clément Léger Signed-off-by: Herve Codina --- drivers/mfd/syscon.c | 145 ++++++++++++++++++++++++++++++++++--- include/linux/mfd/syscon.h | 18 +++++ 2 files changed, 154 insertions(+), 9 deletions(-) diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c index 7d0e91164cba..86898831b842 100644 --- a/drivers/mfd/syscon.c +++ b/drivers/mfd/syscon.c @@ -34,6 +34,7 @@ struct syscon { struct regmap *regmap; struct reset_control *reset; struct list_head list; + struct kref refcount; }; static const struct regmap_config syscon_regmap_config = { @@ -147,6 +148,8 @@ static struct syscon *of_syscon_register(struct device_node *np, bool check_res) syscon->regmap = regmap; syscon->np = np; + of_node_get(syscon->np); + kref_init(&syscon->refcount); spin_lock(&syscon_list_slock); list_add_tail(&syscon->list, &syscon_list); @@ -168,7 +171,30 @@ static struct syscon *of_syscon_register(struct device_node *np, bool check_res) return ERR_PTR(ret); } -static struct regmap *device_node_get_regmap(struct device_node *np, +static void syscon_free(struct kref *kref) +{ + struct syscon *syscon = container_of(kref, struct syscon, refcount); + + spin_lock(&syscon_list_slock); + list_del(&syscon->list); + spin_unlock(&syscon_list_slock); + + regmap_exit(syscon->regmap); + of_node_put(syscon->np); + kfree(syscon); +} + +static void syscon_get(struct syscon *syscon) +{ + kref_get(&syscon->refcount); +} + +static void syscon_put(struct syscon *syscon) +{ + kref_put(&syscon->refcount, syscon_free); +} + +static struct syscon *device_node_get_syscon(struct device_node *np, bool check_res) { struct syscon *entry, *syscon = NULL; @@ -183,9 +209,23 @@ static struct regmap *device_node_get_regmap(struct device_node *np, spin_unlock(&syscon_list_slock); - if (!syscon) + if (!syscon) { syscon = of_syscon_register(np, check_res); + if (IS_ERR(syscon)) + return ERR_CAST(syscon); + } else { + syscon_get(syscon); + } + + return syscon; +} +static struct regmap *device_node_get_regmap(struct device_node *np, + bool check_res) +{ + struct syscon *syscon; + + syscon = device_node_get_syscon(np, check_res); if (IS_ERR(syscon)) return ERR_CAST(syscon); @@ -198,12 +238,23 @@ struct regmap *device_node_to_regmap(struct device_node *np) } EXPORT_SYMBOL_GPL(device_node_to_regmap); -struct regmap *syscon_node_to_regmap(struct device_node *np) +static struct syscon *syscon_node_to_syscon(struct device_node *np) { if (!of_device_is_compatible(np, "syscon")) return ERR_PTR(-EINVAL); - return device_node_get_regmap(np, true); + return device_node_get_syscon(np, true); +} + +struct regmap *syscon_node_to_regmap(struct device_node *np) +{ + struct syscon *syscon; + + syscon = syscon_node_to_syscon(np); + if (IS_ERR(syscon)) + return ERR_CAST(syscon); + + return syscon->regmap; } EXPORT_SYMBOL_GPL(syscon_node_to_regmap); @@ -223,11 +274,11 @@ struct regmap *syscon_regmap_lookup_by_compatible(const char *s) } EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible); -struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np, - const char *property) +static struct syscon *syscon_lookup_by_phandle(struct device_node *np, + const char *property) { struct device_node *syscon_np; - struct regmap *regmap; + struct syscon *syscon; if (property) syscon_np = of_parse_phandle(np, property, 0); @@ -237,12 +288,24 @@ struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np, if (!syscon_np) return ERR_PTR(-ENODEV); - regmap = syscon_node_to_regmap(syscon_np); + syscon = syscon_node_to_syscon(syscon_np); if (property) of_node_put(syscon_np); - return regmap; + return syscon; +} + +struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np, + const char *property) +{ + struct syscon *syscon; + + syscon = syscon_lookup_by_phandle(np, property); + if (IS_ERR(syscon)) + return ERR_CAST(syscon); + + return syscon->regmap; } EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle); @@ -293,6 +356,70 @@ struct regmap *syscon_regmap_lookup_by_phandle_optional(struct device_node *np, } EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_optional); +static struct syscon *syscon_from_regmap(struct regmap *regmap) +{ + struct syscon *entry, *syscon = NULL; + + spin_lock(&syscon_list_slock); + + list_for_each_entry(entry, &syscon_list, list) + if (entry->regmap == regmap) { + syscon = entry; + break; + } + + spin_unlock(&syscon_list_slock); + + return syscon; +} + +void syscon_put_regmap(struct regmap *regmap) +{ + struct syscon *syscon; + + syscon = syscon_from_regmap(regmap); + if (!syscon) + return; + + syscon_put(syscon); +} +EXPORT_SYMBOL_GPL(syscon_put_regmap); + +static void devm_syscon_release(struct device *dev, void *res) +{ + syscon_put(*(struct syscon **)res); +} + +static struct regmap *__devm_syscon_get(struct device *dev, + struct syscon *syscon) +{ + struct syscon **ptr; + + if (IS_ERR(syscon)) + return ERR_CAST(syscon); + + ptr = devres_alloc(devm_syscon_release, sizeof(struct syscon *), GFP_KERNEL); + if (!ptr) { + syscon_put(syscon); + return ERR_PTR(-ENOMEM); + } + + *ptr = syscon; + devres_add(dev, ptr); + + return syscon->regmap; +} + +struct regmap *devm_syscon_regmap_lookup_by_phandle(struct device *dev, + struct device_node *np, + const char *property) +{ + struct syscon *syscon = syscon_lookup_by_phandle(np, property); + + return __devm_syscon_get(dev, syscon); +} +EXPORT_SYMBOL_GPL(devm_syscon_regmap_lookup_by_phandle); + static int syscon_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; diff --git a/include/linux/mfd/syscon.h b/include/linux/mfd/syscon.h index c315903f6dab..f742d865a37a 100644 --- a/include/linux/mfd/syscon.h +++ b/include/linux/mfd/syscon.h @@ -15,6 +15,7 @@ #include struct device_node; +struct device; #ifdef CONFIG_MFD_SYSCON struct regmap *device_node_to_regmap(struct device_node *np); @@ -28,6 +29,11 @@ struct regmap *syscon_regmap_lookup_by_phandle_args(struct device_node *np, unsigned int *out_args); struct regmap *syscon_regmap_lookup_by_phandle_optional(struct device_node *np, const char *property); +void syscon_put_regmap(struct regmap *regmap); + +struct regmap *devm_syscon_regmap_lookup_by_phandle(struct device *dev, + struct device_node *np, + const char *property); #else static inline struct regmap *device_node_to_regmap(struct device_node *np) { @@ -67,6 +73,18 @@ static inline struct regmap *syscon_regmap_lookup_by_phandle_optional( return NULL; } +static inline void syscon_put_regmap(struct regmap *regmap) +{ +} + +static inline +struct regmap *devm_syscon_regmap_lookup_by_phandle(struct device *dev, + struct device_node *np, + const char *property) +{ + return NULL; +} + #endif #endif /* __LINUX_MFD_SYSCON_H__ */