From mboxrd@z Thu Jan 1 00:00:00 1970 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=-2.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 CAF35C48BDF for ; Fri, 18 Jun 2021 16:58:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AB89461248 for ; Fri, 18 Jun 2021 16:58:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231144AbhFRRBG (ORCPT ); Fri, 18 Jun 2021 13:01:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51060 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230335AbhFRRBG (ORCPT ); Fri, 18 Jun 2021 13:01:06 -0400 Received: from mail-ed1-x536.google.com (mail-ed1-x536.google.com [IPv6:2a00:1450:4864:20::536]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 33906C061574 for ; Fri, 18 Jun 2021 09:58:56 -0700 (PDT) Received: by mail-ed1-x536.google.com with SMTP id c7so8611392edn.6 for ; Fri, 18 Jun 2021 09:58:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:from:date:message-id:subject:to:cc; bh=Z9mbh4A1VzZ/Kc0VyfgtzFFvfJf67o5osf3IxrdP4Ac=; b=DZqFAtruSOP1EmWhZ9WKmB6oeyVbbhY/5aMM58iLr5GfJoLdGoS44wUxqV0neFE+j8 +EGYH2j3Qu9SuKgHiKX6K5589j45+oSguE1XIG1Vi/ZJRfmfGGl3Tq5dL9Tkzab6/UF7 Z2ysj1si2bJ+hC5qU4vyRO/L8TlK+rV+ejEdqyFGLn50wbu7dY5A44L6BlTRpJfWxtIC mDV7GmSqw+I7y+dDNb3HOtUpjEHBy4SypRTbzHD30mX9XW4zFgL4zrc2Vdp/eiL9zHuz fjvVo+TcguGsokK+si0eAXSfcv5+KtCez+wjyPkBQ0J4JWwOPPW57QZO41IFchRmyu8I 1rSA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:from:date:message-id:subject:to:cc; bh=Z9mbh4A1VzZ/Kc0VyfgtzFFvfJf67o5osf3IxrdP4Ac=; b=ZLvqQPTgiHs7ZDbABUEf4KHpug65tBqwVD0p10WxtCUlnZkWXhwG3LX5+6PJGu13O1 Q+H5B7AtPFuy+2+Yfn/xbmoj2Xlb9Y411MpE9Xc9p6kjDPUdSJ/tP9TRqXVho40DBBt7 qf2xIVAwdranzDqDBzlJ/Ms2NtYhGh0UKY+XiDzjAoYTraT8WI8x5jqnKfThQbzxwM7d cPgQ376A48YlZeEdHdaa13h6cD8OUM0YaRQ6/Bsru7vHe6giuCZQNfQ348hpSdK2Y2Jh elG86Go6/yJsHucgLYXA52FQy2VUTlW4PZwKsUqux7N6Uabi4YDoYm6qa1aACk2GMxWI yVrA== X-Gm-Message-State: AOAM5309nQSp18T28MgGK41UIw5S4lqo4jP+TAUnPitdjbodDe0f3cez Wh/y5YnKybHRs/h/E5b82DhqwsZPVwF7TOvmMzFttfPLQTHtFw== X-Google-Smtp-Source: ABdhPJzobLUNP7LjfbO3DqUXR1hBi1ybnmS4ldVU0NMEo7rCcKn+NmChmxCG41RivNgfMTnoDlP/u/hF/UfwjryLj5w= X-Received: by 2002:aa7:c0da:: with SMTP id j26mr6162229edp.38.1624035534388; Fri, 18 Jun 2021 09:58:54 -0700 (PDT) MIME-Version: 1.0 From: Adam Ford Date: Fri, 18 Jun 2021 11:58:43 -0500 Message-ID: Subject: ECSPI Slave on i.M8M Mini with DMA To: linux-spi , NXP Linux Team Cc: Charles Stevens Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org To the NXP team, I noticed the spi-imx driver has a function called spi_imx_can_dma() which returns false if the SPI is configured as a slave, so the dma cannot be used in slave mode. Section 10.1.2.7 "DMA" of the The 8MM Ref manual, Rev 3, shows there are a few conditions that can trigger the DMA. Of them, two are RXFIFO data request and RXFIFO full. The block diagram in that section shows it can retrieve data with DMA However, in section 10.1.4 "Applications" of the same document, it shows the optional DMA configurations are only in the SPI master configuration and not the SPI slave configuration. The ECSPIx_DMAREG documentation (section 10.1.5.6) states "The ECSPI sends out DMA requests when the appropriate FIFO conditions are matched." Unfortunately it doesn't explicitly state whether that's only for master or available in either master or slave mode. Can someone tell me if DMA is available when SPI is configured as a slave? thank you, adam