From patchwork Wed Nov 4 10:39:27 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Nicolas Saenz Julienne X-Patchwork-Id: 11880365 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=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT 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 5956DC388F7 for ; Wed, 4 Nov 2020 10:41:17 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D610A2072C for ; Wed, 4 Nov 2020 10:41:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="aYH3BovB" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D610A2072C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To:Message-Id:Date: Subject:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=vUKy9Ao2kImBf1IaFnIUrS/D11TVVFYFG2/7qWI3t5o=; b=aYH3BovBY9NfT0OWB4t53sZSQ MFzl30EVbr574z60VuTfqxVcOK/Kt5P3IUi+O1Eq5lRWve5ebH6ZTwxmk1J92Y/OKVI1WYdqUVesi ouzHm+vEaixakl7tOJxiAnEUl2GUcQQ5/5GIoMUpBS869zRd/aG3j9dneZbAPi4ZDmnr4S69nZhP3 ewzD4LqY4w6gjel7MmzVDQHvtOYufdjSGyTz9wGx2xA7/I5ZLmztG9WTZC3Z1C5C3dFIJjWFTRkrM JzTS2VT+3IgtCdrpD157EQPBbX/6ZifjQi+nHsDFNJ3wACJYB827RevdPQb2krZ9BH2nH5zC97GLx c+TltUa2A==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kaGDY-0003M6-2G; Wed, 04 Nov 2020 10:40:40 +0000 Received: from mx2.suse.de ([195.135.220.15]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kaGCk-0002vI-7n; Wed, 04 Nov 2020 10:39:52 +0000 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id EF2D3AD76; Wed, 4 Nov 2020 10:39:48 +0000 (UTC) From: Nicolas Saenz Julienne To: u.kleine-koenig@pengutronix.de, linux-kernel@vger.kernel.org, Nicolas Saenz Julienne , Florian Fainelli , Ray Jui , Scott Branden , bcm-kernel-feedback-list@broadcom.com Subject: [PATCH v3 01/11] firmware: raspberrypi: Introduce devm_rpi_firmware_get() Date: Wed, 4 Nov 2020 11:39:27 +0100 Message-Id: <20201104103938.1286-2-nsaenzjulienne@suse.de> X-Mailer: git-send-email 2.29.1 In-Reply-To: <20201104103938.1286-1-nsaenzjulienne@suse.de> References: <20201104103938.1286-1-nsaenzjulienne@suse.de> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201104_053950_583726_E1062520 X-CRM114-Status: GOOD ( 19.29 ) 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: devel@driverdev.osuosl.org, linux-pwm@vger.kernel.org, devicetree@vger.kernel.org, sboyd@kernel.org, gregkh@linuxfoundation.org, linus.walleij@linaro.org, dmitry.torokhov@gmail.com, linux-gpio@vger.kernel.org, andy.shevchenko@gmail.com, wahrenst@gmx.net, p.zabel@pengutronix.de, linux-input@vger.kernel.org, bgolaszewski@baylibre.com, linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rpi-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org When unbinding the firmware device we need to make sure it has no consumers left. Otherwise we'd leave them with a firmware handle pointing at freed memory. Keep a reference count of all consumers and introduce devm_rpi_firmware_get() which will automatically decrease the reference count upon unbinding consumer drivers. Suggested-by: Uwe Kleine-König Signed-off-by: Nicolas Saenz Julienne --- Changes since v2: - Create devm_rpi_firmware_get() drivers/firmware/raspberrypi.c | 46 ++++++++++++++++++++++ include/soc/bcm2835/raspberrypi-firmware.h | 8 ++++ 2 files changed, 54 insertions(+) diff --git a/drivers/firmware/raspberrypi.c b/drivers/firmware/raspberrypi.c index 2371d08bdd17..74bdb3bde9dc 100644 --- a/drivers/firmware/raspberrypi.c +++ b/drivers/firmware/raspberrypi.c @@ -11,7 +11,9 @@ #include #include #include +#include #include +#include #include #define MBOX_MSG(chan, data28) (((data28) & ~0xf) | ((chan) & 0xf)) @@ -27,6 +29,9 @@ struct rpi_firmware { struct mbox_chan *chan; /* The property channel. */ struct completion c; u32 enabled; + + refcount_t consumers; + wait_queue_head_t wait; }; static DEFINE_MUTEX(transaction_lock); @@ -247,6 +252,8 @@ static int rpi_firmware_probe(struct platform_device *pdev) } init_completion(&fw->c); + refcount_set(&fw->consumers, 1); + init_waitqueue_head(&fw->wait); platform_set_drvdata(pdev, fw); @@ -275,11 +282,21 @@ static int rpi_firmware_remove(struct platform_device *pdev) rpi_hwmon = NULL; platform_device_unregister(rpi_clk); rpi_clk = NULL; + + wait_event(fw->wait, refcount_dec_if_one(&fw->consumers)); mbox_free_channel(fw->chan); return 0; } +static void rpi_firmware_put(void *data) +{ + struct rpi_firmware *fw = data; + + refcount_dec(&fw->consumers); + wake_up(&fw->wait); +} + /** * rpi_firmware_get - Get pointer to rpi_firmware structure. * @firmware_node: Pointer to the firmware Device Tree node. @@ -297,6 +314,35 @@ struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node) } EXPORT_SYMBOL_GPL(rpi_firmware_get); +/** + * devm_rpi_firmware_get - Get pointer to rpi_firmware structure. + * @firmware_node: Pointer to the firmware Device Tree node. + * + * Returns NULL is the firmware device is not ready. + */ +struct rpi_firmware *devm_rpi_firmware_get(struct device *dev, + struct device_node *firmware_node) +{ + struct platform_device *pdev = of_find_device_by_node(firmware_node); + struct rpi_firmware *fw; + + if (!pdev) + return NULL; + + fw = platform_get_drvdata(pdev); + if (!fw) + return NULL; + + if (!refcount_inc_not_zero(&fw->consumers)) + return NULL; + + if (devm_add_action_or_reset(dev, rpi_firmware_put, fw)) + return NULL; + + return fw; +} +EXPORT_SYMBOL_GPL(devm_rpi_firmware_get); + static const struct of_device_id rpi_firmware_of_match[] = { { .compatible = "raspberrypi,bcm2835-firmware", }, {}, diff --git a/include/soc/bcm2835/raspberrypi-firmware.h b/include/soc/bcm2835/raspberrypi-firmware.h index cc9cdbc66403..8fe64f53a394 100644 --- a/include/soc/bcm2835/raspberrypi-firmware.h +++ b/include/soc/bcm2835/raspberrypi-firmware.h @@ -141,6 +141,8 @@ int rpi_firmware_property(struct rpi_firmware *fw, int rpi_firmware_property_list(struct rpi_firmware *fw, void *data, size_t tag_size); struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node); +struct rpi_firmware *devm_rpi_firmware_get(struct device *dev, + struct device_node *firmware_node); #else static inline int rpi_firmware_property(struct rpi_firmware *fw, u32 tag, void *data, size_t len) @@ -158,6 +160,12 @@ static inline struct rpi_firmware *rpi_firmware_get(struct device_node *firmware { return NULL; } + +static inline struct rpi_firmware *devm_rpi_firmware_get(struct device *dev, + struct device_node *firmware_node) +{ + return NULL; +} #endif #endif /* __SOC_RASPBERRY_FIRMWARE_H__ */