From patchwork Thu Aug 8 15:46:52 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Herve Codina X-Patchwork-Id: 13757741 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 6A010C52D7B for ; Thu, 8 Aug 2024 15:50:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type: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=aXBJioeNV8RpjNiHawY0lmGxzirVjPVLqjUsn2BzB0g=; b=FwXKUtuprvQ4nQ6VJb3mkmRsfu XuXhL8J69u0x0a3rlDrspkOunS/zt3eSsOLGrD3i6iOzEgapF9xDr67n/eoK6bDuEXA4ZdycX0Rco CR7HZdO1AkAoyj5BTblPcJprHUVcaEkLmbQQl1Mf9xlYVe7k+PEwWoqUrYxN9OvUsUHtbMfant+eA 9dUqoorqjDWkLvQo5+2PTn41BCsKF1+gHpIuqzSvZzUj2H1e8U4YmbwHXzuVEF81MVGHHq4GW1r87 Dmvutkwrfhgp/+UCt0gdOphTe7sdPwun3b+gXicpOR4NDZi0NPSOESOkeDP88rU+DpkNDjrvF2NUX RggzoCRg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sc5Op-00000008pWB-14nF; Thu, 08 Aug 2024 15:49:59 +0000 Received: from relay7-d.mail.gandi.net ([2001:4b98:dc4:8::227]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1sc5MX-00000008oil-1oMe for linux-arm-kernel@lists.infradead.org; Thu, 08 Aug 2024 15:47:39 +0000 Received: by mail.gandi.net (Postfix) with ESMTPA id 5B72120007; Thu, 8 Aug 2024 15:47:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1723132056; 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=aXBJioeNV8RpjNiHawY0lmGxzirVjPVLqjUsn2BzB0g=; b=T934UErESkris6q+5HGxD7t+02mDZ5FIZE6o/PI+SU81ms+L8DGHfJkcPIICfvSlx2Ze6m qM4Nmmoz6G81XmZnaviOR1/zu+Da/4JpjINHU9i74k5mmM87R6ciYei/LsAKRr+w1GxtCF ER7A9ZRwL88ffbp49/Yf68WMuevkLlUhjwwtBUxACzCDDI1tusrwruSsx4W/y0mBgNdcbJ mSuwpMv0oyzy5/Rw+iwfbKb+zB2AQzdEWO0ZZivayX15I7As4NgPYufIs5A9IUdc9l2dYX 0KJUgQYAVu5JWObZJz8PB7Id95/6OtuJW/8ZGE4x3hQJ/aVwR/tgfowps3EvKA== From: Herve Codina To: Geert Uytterhoeven , Andy Shevchenko , Simon Horman , Lee Jones , Arnd Bergmann , Derek Kiernan , Dragan Cvetic , Greg Kroah-Hartman , Herve Codina , Bjorn Helgaas , Philipp Zabel , Lars Povlsen , Steen Hegelund , Daniel Machon , UNGLinuxDriver@microchip.com, Rob Herring , Saravana Kannan Cc: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Horatiu Vultur , Andrew Lunn , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, Allan Nielsen , Steen Hegelund , Luca Ceresoli , Thomas Petazzoni , =?utf-8?b?Q2zDqW1lbnQgTMOp?= =?utf-8?b?Z2Vy?= Subject: [PATCH v5 3/8] mfd: syscon: Add reference counting and device managed support Date: Thu, 8 Aug 2024 17:46:52 +0200 Message-ID: <20240808154658.247873-4-herve.codina@bootlin.com> X-Mailer: git-send-email 2.45.0 In-Reply-To: <20240808154658.247873-1-herve.codina@bootlin.com> References: <20240808154658.247873-1-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-20240808_084737_811116_A16FB5DD X-CRM114-Status: GOOD ( 21.52 ) 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 retrieves 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 | 138 ++++++++++++++++++++++++++++++++++--- include/linux/mfd/syscon.h | 16 +++++ 2 files changed, 144 insertions(+), 10 deletions(-) diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c index 33f1e07ab24d..a0f8737b8d63 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 +171,31 @@ 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 struct syscon *syscon_get(struct syscon *syscon) +{ + kref_get(&syscon->refcount); + return syscon; +} + +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 +210,18 @@ static struct regmap *device_node_get_regmap(struct device_node *np, spin_unlock(&syscon_list_slock); - if (!syscon) - syscon = of_syscon_register(np, check_res); + if (syscon) + return syscon_get(syscon); + + return of_syscon_register(np, check_res); +} + +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); @@ -246,12 +282,23 @@ 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); @@ -271,11 +318,11 @@ 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); @@ -285,12 +332,24 @@ 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); @@ -341,6 +400,65 @@ 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(void *syscon) +{ + syscon_put(syscon); +} + +static struct regmap *__devm_syscon_get(struct device *dev, + struct syscon *syscon) +{ + int ret; + + if (IS_ERR(syscon)) + return ERR_CAST(syscon); + + ret = devm_add_action_or_reset(dev, devm_syscon_release, syscon); + if (ret) + return ERR_PTR(ret); + + 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 aad9c6b50463..a3025b4efb4a 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); @@ -30,6 +31,10 @@ struct regmap *syscon_regmap_lookup_by_phandle_optional(struct device_node *np, const char *property); int of_syscon_register_regmap(struct device_node *np, struct regmap *regmap); +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) { @@ -73,6 +78,17 @@ static inline int of_syscon_register_regmap(struct device_node *np, struct regmap *regmap) { return -EOPNOTSUPP; + +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