From: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> To: u.kleine-koenig@pengutronix.de, linux-kernel@vger.kernel.org, Nicolas Saenz Julienne <nsaenzjulienne@suse.de>, Florian Fainelli <f.fainelli@gmail.com>, Ray Jui <rjui@broadcom.com>, Scott Branden <sbranden@broadcom.com>, bcm-kernel-feedback-list@broadcom.com 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 Subject: [PATCH v5 01/11] firmware: raspberrypi: Keep count of all consumers Date: Mon, 23 Nov 2020 19:38:22 +0100 Message-ID: <20201123183833.18750-2-nsaenzjulienne@suse.de> (raw) In-Reply-To: <20201123183833.18750-1-nsaenzjulienne@suse.de> 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 rpi_firmware_put() which will permit automatically decrease the reference count upon unbinding consumer drivers. Suggested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> --- Changes since v3: - Use kref instead of waiting on refcount drivers/firmware/raspberrypi.c | 37 +++++++++++++++++++--- include/soc/bcm2835/raspberrypi-firmware.h | 2 ++ 2 files changed, 35 insertions(+), 4 deletions(-) diff --git a/drivers/firmware/raspberrypi.c b/drivers/firmware/raspberrypi.c index 30259dc9b805..ed793aef7851 100644 --- a/drivers/firmware/raspberrypi.c +++ b/drivers/firmware/raspberrypi.c @@ -7,6 +7,7 @@ */ #include <linux/dma-mapping.h> +#include <linux/kref.h> #include <linux/mailbox_client.h> #include <linux/module.h> #include <linux/of_platform.h> @@ -27,6 +28,8 @@ struct rpi_firmware { struct mbox_chan *chan; /* The property channel. */ struct completion c; u32 enabled; + + struct kref consumers; }; static DEFINE_MUTEX(transaction_lock); @@ -225,12 +228,27 @@ static void rpi_register_clk_driver(struct device *dev) -1, NULL, 0); } +static void rpi_firmware_delete(struct kref *kref) +{ + struct rpi_firmware *fw = container_of(kref, struct rpi_firmware, + consumers); + + mbox_free_channel(fw->chan); + kfree(fw); +} + +void rpi_firmware_put(struct rpi_firmware *fw) +{ + kref_put(&fw->consumers, rpi_firmware_delete); +} +EXPORT_SYMBOL_GPL(rpi_firmware_put); + static int rpi_firmware_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; struct rpi_firmware *fw; - fw = devm_kzalloc(dev, sizeof(*fw), GFP_KERNEL); + fw = kzalloc(sizeof(*fw), GFP_KERNEL); if (!fw) return -ENOMEM; @@ -247,6 +265,7 @@ static int rpi_firmware_probe(struct platform_device *pdev) } init_completion(&fw->c); + kref_init(&fw->consumers); platform_set_drvdata(pdev, fw); @@ -275,25 +294,35 @@ static int rpi_firmware_remove(struct platform_device *pdev) rpi_hwmon = NULL; platform_device_unregister(rpi_clk); rpi_clk = NULL; - mbox_free_channel(fw->chan); + + rpi_firmware_put(fw); return 0; } /** - * rpi_firmware_get - Get pointer to rpi_firmware structure. * @firmware_node: Pointer to the firmware Device Tree node. * + * The reference to rpi_firmware has to be released with rpi_firmware_put(). + * * Returns NULL is the firmware device is not ready. */ struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node) { struct platform_device *pdev = of_find_device_by_node(firmware_node); + struct rpi_firmware *fw; if (!pdev) return NULL; - return platform_get_drvdata(pdev); + fw = platform_get_drvdata(pdev); + if (!fw) + return NULL; + + if (!kref_get_unless_zero(&fw->consumers)) + return NULL; + + return fw; } EXPORT_SYMBOL_GPL(rpi_firmware_get); diff --git a/include/soc/bcm2835/raspberrypi-firmware.h b/include/soc/bcm2835/raspberrypi-firmware.h index cc9cdbc66403..fdfef7fe40df 100644 --- a/include/soc/bcm2835/raspberrypi-firmware.h +++ b/include/soc/bcm2835/raspberrypi-firmware.h @@ -140,6 +140,7 @@ int rpi_firmware_property(struct rpi_firmware *fw, u32 tag, void *data, size_t len); int rpi_firmware_property_list(struct rpi_firmware *fw, void *data, size_t tag_size); +void rpi_firmware_put(struct rpi_firmware *fw); struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node); #else static inline int rpi_firmware_property(struct rpi_firmware *fw, u32 tag, @@ -154,6 +155,7 @@ static inline int rpi_firmware_property_list(struct rpi_firmware *fw, return -ENOSYS; } +static inline void rpi_firmware_put(struct rpi_firmware *fw) { } static inline struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node) { return NULL; -- 2.29.2 _______________________________________________ devel mailing list devel@linuxdriverproject.org http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
next prev parent reply index Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-11-23 18:38 [PATCH v5 00/11] Raspberry Pi PoE HAT fan support Nicolas Saenz Julienne 2020-11-23 18:38 ` Nicolas Saenz Julienne [this message] 2020-12-02 17:26 ` [PATCH v5 01/11] firmware: raspberrypi: Keep count of all consumers Florian Fainelli 2020-12-03 8:05 ` Bartosz Golaszewski 2020-12-03 8:53 ` Nicolas Saenz Julienne 2020-11-23 18:38 ` [PATCH v5 02/11] firmware: raspberrypi: Introduce devm_rpi_firmware_get() Nicolas Saenz Julienne 2020-12-02 17:27 ` Florian Fainelli 2020-11-23 18:38 ` [PATCH v5 03/11] clk: bcm: rpi: Release firmware handle on unbind Nicolas Saenz Julienne 2020-12-02 17:28 ` Florian Fainelli 2020-11-23 18:38 ` [PATCH v5 04/11] gpio: raspberrypi-exp: " Nicolas Saenz Julienne 2020-12-02 17:29 ` Florian Fainelli 2020-11-23 18:38 ` [PATCH v5 05/11] reset: raspberrypi: " Nicolas Saenz Julienne 2020-12-02 17:29 ` Florian Fainelli 2020-11-23 18:38 ` [PATCH v5 06/11] soc: bcm: raspberrypi-power: " Nicolas Saenz Julienne 2020-12-02 17:55 ` Florian Fainelli 2020-11-23 18:38 ` [PATCH v5 07/11] staging: vchiq: " Nicolas Saenz Julienne 2020-12-02 17:56 ` Florian Fainelli 2020-11-23 18:38 ` [PATCH v5 08/11] input: raspberrypi-ts: Release firmware handle when not needed Nicolas Saenz Julienne 2020-12-02 6:03 ` Dmitry Torokhov 2020-12-03 14:52 ` Nicolas Saenz Julienne 2020-11-23 18:38 ` [PATCH v5 09/11] dt-bindings: pwm: Add binding for RPi firmware PWM bus Nicolas Saenz Julienne 2020-11-23 18:38 ` [PATCH v5 10/11] DO NOT MERGE: ARM: dts: Add RPi's official PoE hat support Nicolas Saenz Julienne 2020-11-23 18:38 ` [PATCH v5 11/11] pwm: Add Raspberry Pi Firmware based PWM bus Nicolas Saenz Julienne 2020-12-09 10:42 ` Nicolas Saenz Julienne
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