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=-0.5 required=3.0 tests=BAYES_00,DKIM_ADSP_CUSTOM_MED, DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 79A8FC4338F for ; Sun, 22 Aug 2021 16:09:40 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E79DA61247 for ; Sun, 22 Aug 2021 16:09:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org E79DA61247 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:35408 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mHq2U-0003MM-TU for qemu-devel@archiver.kernel.org; Sun, 22 Aug 2021 12:09:38 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:36682) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mHq1l-0002UN-OU; Sun, 22 Aug 2021 12:08:53 -0400 Received: from mail-yb1-xb32.google.com ([2607:f8b0:4864:20::b32]:34362) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1mHq1k-0007bT-7z; Sun, 22 Aug 2021 12:08:53 -0400 Received: by mail-yb1-xb32.google.com with SMTP id a93so29231239ybi.1; Sun, 22 Aug 2021 09:08:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=EQ3UnmjaEwnBJi0SF7sp2sDlo5x4+uu/4H3+9r5hYzI=; b=Lm8of4ZfEatfNW6HVW9aJjFrR3uBnXp9Xa4lyrmVW29VSqnpRNbdDiukeYUvcSIn96 xjeeYYJzXtLuPbc8DPWjE0MIsdvXln1PPCcHWE7ErA6APUWoIj+gRUTz9ln5jsd4MImb VkFW7DsHkYwvBvJksiitcXGv0sYVTzicYzeeCKNxsE9rIcvNYntAyFZ+DD9J5eZgdPpF yBtwUJdbj62gyzs7FPQLDmOqOIxGU4K0QB6lXNc+qqWzNseR+1AAe1zcEY+n1qZpryCg OH8mY3PKcXYeIs+krDmp0fanK5lb1cM7CcY5XNeOzIv9Dow2G9rVtuRnl0q2W6c5hFj8 3BOg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=EQ3UnmjaEwnBJi0SF7sp2sDlo5x4+uu/4H3+9r5hYzI=; b=Kq/JweI8crO1ZA/nVymR+qU92KWy9iCXgzYxA4ZnGoksD3xOBvY2uyKixN2JM2BGAm DXjfPQZSNo5nEGkLrnzcjcfEGshc7FYFWlR7hGN3M2Jfl+g5eYcWHDAu7gDjrYgNDVnY RJiDjBxdqlo4mWIzOfy37Nw5j2XsSVofYEBG6S53kBVp6h3THR/T+wzdRdRSjPd+iTQq hEwAumuet+Z/fsSN72Bi97n2zHmMfziQZFZP+zA3KVb6sTcAdrK0tK8Fk15I+W4T/F81 hDS6vi1iSIFiGAZqO66JbXu1KRugnOLQEj0KMHiwtqPfJnucjBybfX4mbISsgRgoIH2c QMkg== X-Gm-Message-State: AOAM532p5aDsdUdXGzU0R8NXwUQqF9hIfsV7+CVnk4gGSkfONxdKKatj W/S8mxzkU5JvhHsfT8i+mm392dweoPWtq0RHCgw= X-Google-Smtp-Source: ABdhPJzZ5UOB4eUU4hWGlUKvdJlFOLln1A8nkenz6CnVhqsuGvta/F8YXbbCSub0QWcCq86NIgZ4mNN537Iymn+c0ok= X-Received: by 2002:a5b:391:: with SMTP id k17mr39470676ybp.152.1629648530341; Sun, 22 Aug 2021 09:08:50 -0700 (PDT) MIME-Version: 1.0 References: <20210821154505.18033-1-bmeng.cn@gmail.com> In-Reply-To: From: Bin Meng Date: Mon, 23 Aug 2021 00:08:39 +0800 Message-ID: Subject: Re: [For 6.1 PATCH] hw/arm: xilinx_zynq: Disconnect the UART clocks temporarily To: Peter Maydell Content-Type: text/plain; charset="UTF-8" Received-SPF: pass client-ip=2607:f8b0:4864:20::b32; envelope-from=bmeng.cn@gmail.com; helo=mail-yb1-xb32.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Damien Hedde , "Edgar E . Iglesias" , qemu-arm , Alistair Francis , QEMU Developers Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Sun, Aug 22, 2021 at 2:14 AM Peter Maydell wrote: > > On Sat, 21 Aug 2021 at 16:45, Bin Meng wrote: > > > > As of today, when booting upstream U-Boot for Xilinx Zynq, the UART > > does not receive anything. Initial debugging shows that the UART clock > > frequency is 0 somehow which prevents the UART from receiving anything. > > Note the U-Boot can still output data to the UART tx fifo, which should > > not happen, as the design seems to prevent the data transmission when > > clock is not enabled but somehow it only applies to the Rx side. > > > > For anyone who is interested to give a try, here is the U-Boot defconfig: > > $ make xilinx_zynq_virt_defconfig > > > > and QEMU commands to test U-Boot: > > $ qemu-system-arm -M xilinx-zynq-a9 -m 1G -display none -serial null -serial stdio \ > > -device loader,file=u-boot-dtb.bin,addr=0x4000000,cpu-num=0 > > > > Note U-Boot used to boot properly in QEMU 4.2.0 which is the QEMU > > version used in current U-Boot's CI testing. The UART clock changes > > were introduced by the following 3 commits: > > > > 38867cb7ec90 ("hw/misc/zynq_slcr: add clock generation for uarts") > > b636db306e06 ("hw/char/cadence_uart: add clock support") > > 5b49a34c6800 ("hw/arm/xilinx_zynq: connect uart clocks to slcr") > > > > Looks like we don't have enough time to figure out a proper fix before > > 6.1.0 release date, let's disconnect the UART clocks temporarily. > > This is too late for 6.1 regardless, I'm afraid. That's too bad :( I figured out a proper fix, and will send it out soon. Regards, Bin