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 <u.kleine-koenig@xxxxxxxxxxxxxx> Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@xxxxxxx> --- 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 <linux/module.h> #include <linux/of_platform.h> #include <linux/platform_device.h> +#include <linux/refcount.h> #include <linux/slab.h> +#include <linux/wait.h> #include <soc/bcm2835/raspberrypi-firmware.h> #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__ */ -- 2.29.1 _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel