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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 79904CA0EFA for ; Mon, 25 Aug 2025 12:52:58 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1uqWfZ-0006La-S9; Mon, 25 Aug 2025 08:51:29 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1uqWej-00069c-Ox for qemu-devel@nongnu.org; Mon, 25 Aug 2025 08:50:42 -0400 Received: from mail-yb1-xb33.google.com ([2607:f8b0:4864:20::b33]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1uqWeg-0005og-NM for qemu-devel@nongnu.org; Mon, 25 Aug 2025 08:50:37 -0400 Received: by mail-yb1-xb33.google.com with SMTP id 3f1490d57ef6-e933a69651dso3644262276.1 for ; Mon, 25 Aug 2025 05:50:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1756126231; x=1756731031; darn=nongnu.org; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=gTqtUTTq9GgaC3p+iimp2St44Dw0MIbEASnueVReolE=; b=Gg1rmEI0utV5QJKlEPiDAy0UGr9ShNETW57dWZEz2UU68tUyow9zYQLpt89R/b48F+ snxdFPUf8BivC0vex0JIQdRQBGf3ZXXMZuHweRSP6mfRvLKu19xoEV7p7vzUmTZOzsVp StLV9O3ltdW+Z7Ucx0bVFGYNBa8Z5+56IoxuLCB3CMYnzWps/P5EKS/HoqKhi+CaNEml bsLDX+eqmMnUsWBCuTfYVib5zVcWu5SQQvRvk7lB6zlNGlSTXgvYd8XiNtgHCghQ/r41 Anyok/JMCQjPtlpNjSfjHglgOF6Z26c7lHEORu3L0UuO8JLiBP3hKjJRQUjgixiA4141 AWXw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1756126231; x=1756731031; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=gTqtUTTq9GgaC3p+iimp2St44Dw0MIbEASnueVReolE=; b=E4KmOvBpJg9oZ06Dj7WlTl/skJAn0zIDp4i5jbSyvYM0eQdzN0azhzq4AGZeXAgU8g MH6LzvkQUDF7qKFAFfJMYcw9qYD6vdLOvg9eQgHDbi/rHQSiUUoLRXf439oAn9AIOzLe izKLp128HBczL41UGuM0IHfyDF3s9xFjxFcGaZj6UOhwhpXtbl+uC2OuQUKyjDB/k6Rb UbDpYXRHUCTHC0rn1jEPWelcm6KJSMzeWe2KPV3Orfc460k8mIQPnkNWncWnkD/k3ybM qjmX+GvhDUFWzk4zdUlpJaewAuzPsAoR4h45lhl8Q3UHa9/i9zyTo8nYMNkOJ625Hc1Z Qs/A== X-Gm-Message-State: AOJu0Yy601Jo8yE4GGjaZMr1KsN2/xkD0P/A4CLStuB3sP/Fk5jWrdJs XKsi/T/mhksC0DVucD1ivY0NXeRivD8ZZjd9DCbWrOjorxZgjcpdN7sUES+Zop05D+QMS6kUMN3 N+PfkQHoljL3VKxSvMICQwrsS8h0Ay3UTeS+Y64TGeQ== X-Gm-Gg: ASbGncvBHAAdWMqscrHfjpItgLtlvYEpeYuEE6Ld7ijyhHdFRd5A69M3DNTULrIDBMN i8+ebGGREpK7XE9EZAFK+7qDhInKHL0yc8uoRWydpyQJlK/EGjrH7ZJbqHp6k+Hfz6SWXdUsf9i CTvQ0+Nuo2s7wAJtfdTHglIbNIortm2VajCOkn1Y1OY2zThzzdQ2XnmbsujxmrDPKq8v+Qg3CVj pZvNTOc X-Google-Smtp-Source: AGHT+IHt6cGE7TUtM5RFNFgjRWqIFsrdpCPCo2LvBhM2g4r430YFAhZv3tD4u6+Cz3BTv7/YySO03xIR6z/Jm+gtCZ8= X-Received: by 2002:a05:6902:188f:b0:e95:f5f5:60ef with SMTP id 3f1490d57ef6-e95f5f56a67mr2894040276.8.1756126230921; Mon, 25 Aug 2025 05:50:30 -0700 (PDT) MIME-Version: 1.0 References: <20250809211051.68824-1-chichikalyuk@gmail.com> <0B0D958D-67D8-4036-A6BD-75CBD7DC636C@gmail.com> In-Reply-To: <0B0D958D-67D8-4036-A6BD-75CBD7DC636C@gmail.com> From: Peter Maydell Date: Mon, 25 Aug 2025 13:50:19 +0100 X-Gm-Features: Ac12FXzRHwO-yHDFIOa5BkKSrHfzm6X9nGg1kUnX4dMGzmtCIaWpz7GsjisP4QI Message-ID: Subject: Re: [PATCH v2 0/3] hw: acpi: add UART clock freq to AArch64 SPCR To: Vadim Chichikalyuk Cc: qemu-devel@nongnu.org, qemu-arm@nongnu.org, "Michael S. Tsirkin" , Igor Mammedov , Ani Sinha , Shannon Zhao Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=2607:f8b0:4864:20::b33; envelope-from=peter.maydell@linaro.org; helo=mail-yb1-xb33.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, 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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Mon, 25 Aug 2025 at 00:00, Vadim Chichikalyuk w= rote: > > > > On 18 Aug 2025, at 18:26, Peter Maydell wrot= e: > > > > So, what's the rationale here? QEMU's UART doesn't care about > > clocks at all. We provide a clock in the DTB because the kernel > > refuses to boot if you don't, but if the ACPI spec didn't even > > have a way to pass the clock frequency until rev 4 this obviously > > isn't a problem on that side. > > The rationale is the same =E2=80=93 just as the (Linux?) kernel expects > a clock frequency if a UART is present in the DTB, guests using > ACPI may expect a valid value for the clock frequency in the > SPCR record when one is present. But the ACPI spec prior to rev 4 doesn't even provide a way to specify the clock frequency, so why would a guest expect it, and how could it do so? thanks -- PMM