From patchwork Mon Jul 19 14:53:13 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stephan Gerhold X-Patchwork-Id: 480134 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=-13.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 8671FC636CE for ; Mon, 19 Jul 2021 15:01:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7424A61221 for ; Mon, 19 Jul 2021 15:01:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242649AbhGSOVK (ORCPT ); Mon, 19 Jul 2021 10:21:10 -0400 Received: from mo4-p01-ob.smtp.rzone.de ([85.215.255.52]:11923 "EHLO mo4-p01-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242638AbhGSOUP (ORCPT ); Mon, 19 Jul 2021 10:20:15 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1626706842; s=strato-dkim-0002; d=gerhold.net; h=Message-Id:Date:Subject:Cc:To:From:Cc:Date:From:Subject:Sender; bh=5asqN0lZNo3xHl1CBAymxXSuEQ1yqbDJbz4DcdRrSLk=; b=J9E+jk/CxpvlIzVoB/gE8iHadnpWEZV9qry2QxLZXyEkGS7q4EgvuV9EjmJIRSVpem KeFT3hGVQ6Tj9uCV5zEIE4TqdyV1AFUiM1Hry1Fof7HFo6pNjNOKae5EmecnZ5+DHFRR ayD0gafOmrrg9Tl82I/2xmSaciITVipVQU0LdlBaii+/6w2b6rTJhsuWVkp0VzmKK7rG dTJed3H6EXEJof3peozzJWgjGwHDCJzXg4ijsslOKUowXCcsU+33yb0ApAwQvyh3ituP mZAduTazt+061IzKtbWUOfzTOpzboSLhVsM4fQ9uDmPy2jSNB0JIeCcoNojLHFrxacBP Fy9g== Authentication-Results: strato.com; dkim=none X-RZG-AUTH: ":P3gBZUipdd93FF5ZZvYFPugejmSTVR2nRPhVORvLd4SsytBXS7IYBkLahKxB4m6O43/v" X-RZG-CLASS-ID: mo00 Received: from droid.. by smtp.strato.de (RZmta 47.28.1 DYNA|AUTH) with ESMTPSA id g02a44x6JF0c42H (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Mon, 19 Jul 2021 17:00:38 +0200 (CEST) From: Stephan Gerhold To: "David S. Miller" , Jakub Kicinski Cc: Loic Poulain , Sergey Ryazanov , Johannes Berg , Bjorn Andersson , Andy Gross , Vinod Koul , Rob Herring , Aleksander Morgado , netdev@vger.kernel.org, linux-arm-msm@vger.kernel.org, dmaengine@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, phone-devel@vger.kernel.org, ~postmarketos/upstreaming@lists.sr.ht, Jeffrey Hugo , Stephan Gerhold Subject: [RFC PATCH net-next 0/4] net: wwan: Add Qualcomm BAM-DMUX WWAN network driver Date: Mon, 19 Jul 2021 16:53:13 +0200 Message-Id: <20210719145317.79692-1-stephan@gerhold.net> X-Mailer: git-send-email 2.32.0 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org The BAM Data Multiplexer provides access to the network data channels of modems integrated into many older Qualcomm SoCs, e.g. Qualcomm MSM8916 or MSM8974. This series adds a driver that allows using it. For more information about BAM-DMUX, see PATCH 4/4. Shortly said, BAM-DMUX is built using a simple protocol layer on top of a DMA engine (Qualcomm BAM DMA). For BAM-DMUX, the BAM DMA engine runs in a quite strange mode that I call "remote power collapse", where the modem/remote side is responsible for powering on the BAM when needed but we are responsible to initialize it. The BAM is power-collapsed when unneeded by coordinating power control via bidirectional interrupts from the BAM-DMUX driver. The series first adds one possible solution for handling this "remote power collapse" mode in the bam_dma driver, then it adds the BAM-DMUX driver to the WWAN subsystem. Note that the BAM-DMUX driver does not actually make use of the WWAN subsystem yet, since I'm not sure how to fit it in there yet (see PATCH 4/4). Please note that all of the changes in this patch series are based on a fairly complicated driver from Qualcomm [1]. I do not have access to any documentation about "BAM-DMUX". :( The driver has been used in postmarketOS [2] on various smartphones/tablets based on Qualcomm MSM8916 and MSM8974 for a year now with no reported problems. At runtime (but not compile-time), the following two patches are needed additionally for full functionality: - https://lore.kernel.org/linux-arm-msm/20210712135703.324748-1-stephan@gerhold.net/ - https://lore.kernel.org/linux-arm-msm/20210712135703.324748-2-stephan@gerhold.net/ [1]: https://source.codeaurora.org/quic/la/kernel/msm-3.10/tree/drivers/soc/qcom/bam_dmux.c?h=LA.BR.1.2.9.1-02310-8x16.0 [2]: https://postmarketos.org/ Stephan Gerhold (4): dt-bindings: dmaengine: bam_dma: Add remote power collapse mode dmaengine: qcom: bam_dma: Add remote power collapse mode dt-bindings: net: Add schema for Qualcomm BAM-DMUX net: wwan: Add Qualcomm BAM-DMUX WWAN network driver .../devicetree/bindings/dma/qcom_bam_dma.txt | 2 + .../bindings/net/qcom,bam-dmux.yaml | 87 ++ MAINTAINERS | 8 + drivers/dma/qcom/bam_dma.c | 88 +- drivers/net/wwan/Kconfig | 13 + drivers/net/wwan/Makefile | 1 + drivers/net/wwan/qcom_bam_dmux.c | 907 ++++++++++++++++++ 7 files changed, 1074 insertions(+), 32 deletions(-) create mode 100644 Documentation/devicetree/bindings/net/qcom,bam-dmux.yaml create mode 100644 drivers/net/wwan/qcom_bam_dmux.c