From patchwork Mon Aug 5 10:17:19 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Herve Codina X-Patchwork-Id: 13753432 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 4C889C3DA7F for ; Mon, 5 Aug 2024 10:21:56 +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=AtQAENyFiX4qzjNmAXkQQ8GKLH8T1wLEJY+LVMQa6YI=; b=dl/iV1TTY5A4VTbINlU90vQkqb N/il0ARD8koeBMrS26OuXKdtRf4f5UnGEq9a/YehOnFefvKQlfVFcqYW5/+1KbF/2YekDm650cC1T J9W5THGqM5uZaPlVRFbnd51liI+DLT4swji0j+VTjNipyKEYFgmP0rErU+8p43jopC5jDXgOqhK6U epa9wmCfTDi9SijRjJlbP/jwMg33/tjP2g+evJZeOGyahP0S/qsl+5vuTj5T2BHsH8aZ41DCUNdCP Bba69NitWuo60QcbWCUtb7B0K9vQSvHPZ8TNG+lc0sWUjTShwQFtgCaCtz/J72n29LGPizY1kE5H9 bfTGcbsw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sauqY-0000000FTTt-1Hus; Mon, 05 Aug 2024 10:21:46 +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 1sauod-0000000FSmo-1BNw for linux-arm-kernel@lists.infradead.org; Mon, 05 Aug 2024 10:19:48 +0000 Received: by mail.gandi.net (Postfix) with ESMTPA id 2DE0B20005; Mon, 5 Aug 2024 10:19:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1722853185; 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=AtQAENyFiX4qzjNmAXkQQ8GKLH8T1wLEJY+LVMQa6YI=; b=QG0iu5QTt3SrYsBZb+cvB2pf53ZHW2E1rFJnAXs5kwCX2h5K99SA1B/F0Qo2DASPRTys+e 8CXrKY8m1A/Hmg/Ks6N1pptv09ynip90FERbKjsGO4cNMzo8yvz5Q8h4VYynk499LATzyi 3Y/r8oqSPI7C8TNsB5xf7o1xXNp/JtQedOU7sOhI0VcHPNWYGjQo6lYnc3+0eKUtTwt/uM nx1dkdTCqj6tCNrGlgRRCIQJ/pikWP+Gxz0L92f+dxwNSpEZdjB0AZvZRkpI9ZoE/b4jTB TKYanYlATG12foWKrZgy5vJEojkgOPIEvG6rv8Sql131gfYMqqiD+MJotuKl/Q== 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 v4 3/8] mfd: syscon: Add reference counting and device managed support Date: Mon, 5 Aug 2024 12:17:19 +0200 Message-ID: <20240805101725.93947-4-herve.codina@bootlin.com> X-Mailer: git-send-email 2.45.0 In-Reply-To: <20240805101725.93947-1-herve.codina@bootlin.com> References: <20240805101725.93947-1-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-20240805_031947_644168_1AE6E993 X-CRM114-Status: GOOD ( 22.73 ) 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 | 16 ++++ 2 files changed, 152 insertions(+), 9 deletions(-) diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c index 33f1e07ab24d..b602fa7c5c63 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); @@ -246,12 +286,23 @@ 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 +322,11 @@ 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 +336,24 @@ 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 +404,70 @@ 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 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