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dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.a=rsa-sha256 header.s=2020 header.b=Y/dHatnd; dkim=pass header.d=linutronix.de header.i=@linutronix.de header.a=ed25519-sha256 header.s=2020e header.b=sCe4OyFB From: Gregor Herburger DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1794315629; 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=ay6vWD2zi4p8jnzpFR5chjGsTnlEvy9gzBG4rU0Nmg4=; b=Y/dHatndVjSbJm/Noc3Zm00xavqcA28/4CKm8ffJuh6goUUcA740bS0OmrjVXs8jEzUe6z llw+I2WKNE9djAoquSdNbHYvdwnxSI4ZDY8m9OLc6M3eMoymdCyEDKsJacsfyk1ZkY7pC5 ZcuLOy1ZyHlItTsqnIZ5gbM7ZyzA3NNi68W2ueU7DrnRwKP4bE5l2kxrOPBCn/06O3TD25 GYG6nRlUstd+yG3SsMlZtzHzm5Y0VFZGTf5BaoafHHT9KUEDJ/7neOsB6/LnMbVGvtC2Uw VVRDJjxGfA26H3u/Ci1gsJxEuKDAeCWT7SvZTHvoNcFi6F+HEf8wx4HrDigeFg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1794315629; 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=ay6vWD2zi4p8jnzpFR5chjGsTnlEvy9gzBG4rU0Nmg4=; b=sCe4OyFBiyazCLSMjY6teq5w1zJbD5PGQFWH4Y26Lbcna2gbBAkG1lxVEekDFzxcUXBScn Qxen0VNYrxeIYaBA== Date: Tue, 10 Nov 2026 14:00:13 +0100 Subject: [PATCH v6 3/5] firmware: raspberrypi: Add reboot mode support X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261110-rpi-tryboot-v6-3-56f680ef4734@linutronix.de> References: <20261110-rpi-tryboot-v6-0-56f680ef4734@linutronix.de> In-Reply-To: <20261110-rpi-tryboot-v6-0-56f680ef4734@linutronix.de> To: Florian Fainelli , Broadcom internal kernel review list , Ray Jui , Scott Branden , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Eric Anholt , Stefan Wahren Cc: linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, Gregor Herburger X-Developer-Signature: v=1; a=ed25519-sha256; t=1794315627; l=5746; i=gregor.herburger@linutronix.de; s=20260226; h=from:subject:message-id; bh=aDdenUs6EBEfCsBy5QHSM4GJtsSkWM/+EmSTHKmep9E=; b=eCLDJ2Td63ug2/ZweV7k1t8v+BD5OaGVlaobAXvfFUqmSsx0LXgGEWzxNSLqUxoaNG1Jrknxa /EGzYyTJQ19AoZyEBma/fvVOzJXKb11tfHURkh0W4v32xZAMimMqW29 X-Developer-Key: i=gregor.herburger@linutronix.de; a=ed25519; pk=u72Lv7+/lS5CC1hmSrb17lv/6CK7HBh4Lvz77PHA5LM= The Raspberry Pi firmware has a tryboot mode where it tries to boot from another partition. This can be used to create a A/B update scheme. To enable this on the next boot, the RPI_FIRMWARE_SET_REBOOT_FLAGS message must be sent to the firmware. Add support for this by registering a reboot mode driver. Furthermore, safely registering the reboot mode requires adjusting the teardown sequence. Replace the manually called rpi_firmware_put() with a devres-managed called (devm_add_action_or_reset). Without this, the cleanup function of devm_reboot_mode_register() would trigger a use-after-free error by attempting to access the firmware context after it had already been freed by rpi_firmware_remove(). Tested-by: Stefan Wahren Signed-off-by: Gregor Herburger --- drivers/firmware/Kconfig | 2 ++ drivers/firmware/raspberrypi.c | 40 ++++++++++++++++++++++++++---- include/soc/bcm2835/raspberrypi-firmware.h | 2 ++ 3 files changed, 39 insertions(+), 5 deletions(-) diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig index 43e2e2a645945..0de884adf0b66 100644 --- a/drivers/firmware/Kconfig +++ b/drivers/firmware/Kconfig @@ -142,6 +142,8 @@ config RASPBERRYPI_FIRMWARE depends on ARM || ARM64 depends on MAILBOX default ARCH_BCM2835 + select POWER_RESET + select REBOOT_MODE help This option enables support for communicating with the firmware on the Raspberry Pi. diff --git a/drivers/firmware/raspberrypi.c b/drivers/firmware/raspberrypi.c index 443459c8c90fa..95eb3183ce37d 100644 --- a/drivers/firmware/raspberrypi.c +++ b/drivers/firmware/raspberrypi.c @@ -14,6 +14,7 @@ #include #include #include +#include #include #include @@ -30,6 +31,7 @@ struct rpi_firmware { struct mbox_client cl; struct mbox_chan *chan; /* The property channel. */ struct completion c; + struct reboot_mode_driver reboot_mode; u32 enabled; struct kref consumers; @@ -294,10 +296,37 @@ static void devm_rpi_firmware_put(void *data) rpi_firmware_put(fw); } +static int rpi_firmware_reboot_mode_write(struct reboot_mode_driver *reboot, + unsigned int magic) +{ + struct rpi_firmware *fw = container_of(reboot, struct rpi_firmware, + reboot_mode); + __le32 fw_magic = cpu_to_le32(magic); + + if (!magic) + return 0; + + return rpi_firmware_property(fw, RPI_FIRMWARE_SET_REBOOT_FLAGS, + &fw_magic, sizeof(fw_magic)); +} + +static void rpi_register_reboot_mode(struct device *dev, struct rpi_firmware *fw) +{ + int ret; + + fw->reboot_mode.dev = dev; + fw->reboot_mode.write = rpi_firmware_reboot_mode_write; + ret = devm_reboot_mode_register(dev, &fw->reboot_mode); + if (ret) + dev_err(dev, "Failed to register reboot mode: %d\n", ret); + +} + static int rpi_firmware_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; struct rpi_firmware *fw; + int ret; /* * Memory will be freed by rpi_firmware_delete() once all users have @@ -313,7 +342,7 @@ static int rpi_firmware_probe(struct platform_device *pdev) fw->chan = mbox_request_channel(&fw->cl, 0); if (IS_ERR(fw->chan)) { - int ret = PTR_ERR(fw->chan); + ret = PTR_ERR(fw->chan); kfree(fw); return dev_err_probe(dev, ret, "Failed to get mbox channel\n"); } @@ -321,12 +350,17 @@ static int rpi_firmware_probe(struct platform_device *pdev) init_completion(&fw->c); kref_init(&fw->consumers); + ret = devm_add_action_or_reset(dev, devm_rpi_firmware_put, fw); + if (ret) + return ret; + platform_set_drvdata(pdev, fw); rpi_firmware_print_firmware_revision(fw); rpi_register_hwmon_driver(dev, fw); rpi_register_clk_driver(dev); rpi_register_rtc_driver(dev); + rpi_register_reboot_mode(dev, fw); return 0; } @@ -343,16 +377,12 @@ static void rpi_firmware_shutdown(struct platform_device *pdev) static void rpi_firmware_remove(struct platform_device *pdev) { - struct rpi_firmware *fw = platform_get_drvdata(pdev); - platform_device_unregister(rpi_hwmon); rpi_hwmon = NULL; platform_device_unregister(rpi_clk); rpi_clk = NULL; platform_device_unregister(rpi_rtc); rpi_rtc = NULL; - - rpi_firmware_put(fw); } static const struct of_device_id rpi_firmware_of_match[] = { diff --git a/include/soc/bcm2835/raspberrypi-firmware.h b/include/soc/bcm2835/raspberrypi-firmware.h index 5a0cbb18d0b6c..20141eb2cb678 100644 --- a/include/soc/bcm2835/raspberrypi-firmware.h +++ b/include/soc/bcm2835/raspberrypi-firmware.h @@ -81,6 +81,7 @@ enum rpi_firmware_property_tag { RPI_FIRMWARE_GET_POE_HAT_VAL = 0x00030049, RPI_FIRMWARE_SET_POE_HAT_VAL = 0x00030050, RPI_FIRMWARE_NOTIFY_XHCI_RESET = 0x00030058, + RPI_FIRMWARE_GET_REBOOT_FLAGS = 0x00030064, RPI_FIRMWARE_NOTIFY_DISPLAY_DONE = 0x00030066, RPI_FIRMWARE_GET_RTC_REG = 0x00030087, RPI_FIRMWARE_SET_CLOCK_STATE = 0x00038001, @@ -93,6 +94,7 @@ enum rpi_firmware_property_tag { RPI_FIRMWARE_SET_SDHOST_CLOCK = 0x00038042, RPI_FIRMWARE_SET_GPIO_CONFIG = 0x00038043, RPI_FIRMWARE_SET_PERIPH_REG = 0x00038045, + RPI_FIRMWARE_SET_REBOOT_FLAGS = 0x00038064, RPI_FIRMWARE_SET_RTC_REG = 0x00038087, /* Dispmanx TAGS */ -- 2.47.3