From patchwork Wed Oct 26 13:15:29 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthias Schiffer X-Patchwork-Id: 618975 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3B7F1C433FE for ; Wed, 26 Oct 2022 13:16:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233603AbiJZNQf (ORCPT ); Wed, 26 Oct 2022 09:16:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51568 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233390AbiJZNQf (ORCPT ); Wed, 26 Oct 2022 09:16:35 -0400 Received: from mx1.tq-group.com (mx1.tq-group.com [93.104.207.81]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 21AA4A99D5; Wed, 26 Oct 2022 06:16:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tq-group.com; i=@tq-group.com; q=dns/txt; s=key1; t=1666790194; x=1698326194; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=mjFPBPmpLWz/562nklZTla4ladz+0IGVjIOFuv2LArA=; b=g2Yh5SKETTVgbyXjbhuqHF8wiqtjMF3HD/VnrHDKwvzXNmYOJDKFQxw/ 3u4XyEyUFqjIzr9LsK68QWeHA1zswcujuWJ5/ALwhaaqvcWdeqxVY3pE5 1S0ZcUXDUtrKbdf9EfaNk4dAN4tkZe5ch89w0J4F4DeCGExBBX5vyDmcf V2+b5DSxKMaJ9phlsHoyAC+D7mTjnzt/QzDHpweZbj+1UxWhBXBWjgt3A EEL8Sweo/izH6dickrdNPA1t2ng/I78+hLL0y4aIz/v3knfSAimXt6Bj+ FJJJVGRn6pu+pJnmZs0clvlRzh3eDVJHl3UTuGJxtwTWbTURlmaEL4wTj g==; X-IronPort-AV: E=Sophos;i="5.95,214,1661810400"; d="scan'208";a="26988467" Received: from unknown (HELO tq-pgp-pr1.tq-net.de) ([192.168.6.15]) by mx1-pgp.tq-group.com with ESMTP; 26 Oct 2022 15:16:31 +0200 Received: from mx1.tq-group.com ([192.168.6.7]) by tq-pgp-pr1.tq-net.de (PGP Universal service); Wed, 26 Oct 2022 15:16:31 +0200 X-PGP-Universal: processed; by tq-pgp-pr1.tq-net.de on Wed, 26 Oct 2022 15:16:31 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tq-group.com; i=@tq-group.com; q=dns/txt; s=key1; t=1666790191; x=1698326191; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=mjFPBPmpLWz/562nklZTla4ladz+0IGVjIOFuv2LArA=; b=VkLkxiFpxIRXSvtH9mdheulw/zvTruyrS/vc9L0P69NBK8JYa8AMRgYJ hEHrAkXwDGTMCnRVT3yX3frv80r/tPy4dAIfcw4LCm38awoH0Vhb8HOH7 YWwetleT4ujenU/RvxoXQ2C85ybsZxE9caxuoY89vpapB+JyO7UZ1W99U PtlWKjo/aWDCmUwiVMye0cDfpowfV51SzGDFO0X55SBjdxO9w/SHuDvJV M1RBKlZ/FcnataEHlp2nlFDAKxqKcuATaVjAdDKZ0HTFh4LAjsqvh6DQL RlQz/n1KCzIVoVXfO6kMdVolcnzFfap1Mu/4efFQ76vsoduJJfNx5J87C w==; X-IronPort-AV: E=Sophos;i="5.95,214,1661810400"; d="scan'208";a="26988466" Received: from vtuxmail01.tq-net.de ([10.115.0.20]) by mx1.tq-group.com with ESMTP; 26 Oct 2022 15:16:31 +0200 Received: from localhost.localdomain (SCHIFFERM-M2.tq-net.de [10.121.49.14]) by vtuxmail01.tq-net.de (Postfix) with ESMTPA id BFB01280056; Wed, 26 Oct 2022 15:16:29 +0200 (CEST) From: Matthias Schiffer To: Arnd Bergmann , Greg Kroah-Hartman , Rob Herring , Krzysztof Kozlowski Cc: Marcel Holtmann , Johan Hedberg , Luiz Augusto von Dentz , Amitkumar Karwar , Ganapathi Bhat , Sharvari Harisangam , Xinming Hu , Kalle Valo , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , linux-kernel@vger.kernel.org, linux-bluetooth@vger.kernel.org, linux-wireless@vger.kernel.org, netdev@vger.kernel.org, devicetree@vger.kernel.org, linux@ew.tq-group.com, Matthias Schiffer Subject: [RFC 0/5] "notify-device" for cross-driver readiness notification Date: Wed, 26 Oct 2022 15:15:29 +0200 Message-Id: X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org This patch series is obviously missing documentation, MAINTAINERS entries, etc., but I'd like to solicit some basic feedback on whether this approach makes sense at all before I proceed. If it does, the naming is also very much open for bikeshedding - I'm not too happy with "notify-device". The basic problem that the notify-device tries to solve is the synchronization of firmware loading readiness between the Marvell/NXP WLAN and Bluetooth drivers, but it may also be applicable to other drivers. The WLAN and Bluetooth adapters are handled by separate drivers, and may be connected to the CPU using different interfaces (for example SDIO for WLAN and UART for Bluetooth). However, both adapters share a single firmware that may be uploaded via either interface. For the SDIO+UART case, uploading the firmware via SDIO is usually preferable, but even when the interface doesn't matter, it seems like a good idea to clearly define which driver should handle it. To avoid making the Bluetooth driver more complicated than necessary in this case, we'd like to defer the probing of the driver until the firmware is ready. For this purpose, we are introducing a notify-device, with the following properties: - The device is created by a driver as soon as some "readiness condition" is satisfied - Creating the device also binds a stub driver, so deferred probes are triggered - Looking up the notify device is possible via OF node / phandle reference This approach avoids a hard dependency between the WLAN and Bluetooth driver, and works regardless of the driver load order. The first patch implementes the notify-device driver itself, and the rest shows how the device could be hooked up to the mwifiex and hci_mrvl drivers. A device tree making use of the notify-device could look like the following: &sdhci1 { wifi@1 { compatible = "marvell,sd8987"; reg = <1>; wifi_firmware: firmware-notifier {}; }; }; &main_uart3 { bluetooth { compatible = "marvell,sd8987-bt"; firmware-ready = <&wifi_firmware>; }; }; Matthias Schiffer (5): misc: introduce notify-device driver wireless: mwifiex: signal firmware readiness using notify-device bluetooth: hci_mrvl: select firmwares to load by match data bluetooth: hci_mrvl: add support for SD8987 bluetooth: hci_mrvl: allow waiting for firmware load using notify-device drivers/bluetooth/hci_mrvl.c | 77 ++++++++++++-- drivers/misc/Kconfig | 4 + drivers/misc/Makefile | 1 + drivers/misc/notify-device.c | 109 ++++++++++++++++++++ drivers/net/wireless/marvell/mwifiex/main.c | 14 +++ drivers/net/wireless/marvell/mwifiex/main.h | 1 + include/linux/notify-device.h | 33 ++++++ 7 files changed, 228 insertions(+), 11 deletions(-) create mode 100644 drivers/misc/notify-device.c create mode 100644 include/linux/notify-device.h