From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from m16.mail.163.com (m16.mail.163.com [117.135.210.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7107628C2D9; Wed, 7 May 2025 16:48:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=117.135.210.5 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746636527; cv=none; b=QwI8SOGEPfnTBBDY2rVX7u5sg2DS7XR10GDRWV1LtNoj/DodaQSRQFbygGrIcOwietafp6FemsT91ozxhvk13Df5FkZ+uLI1oLlz0NBU4s0WZAKzQmaDnI6B/txr9R0wqF+KWZGNFN8733jGwjcHII69I1kvhrto1D5UpRCln+0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746636527; c=relaxed/simple; bh=V7SF7M97q+1MYK6Hkfl9CybNPto1Pxcqsg0UIAI2GTA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=u4ZhcWhEk8QpwyXUU/kUQpv2rsqU7DBOZFCZx8LJZ4trDDPYq9GChznJBrM09TaviV3WyeuUy/Wika6nvbgQkkPC9BeVv9NIcHuz2dbOM9A7hbHs3/h9UTykhi7fevRNjlPe8TllVC0lfoUbjnPbKMJPN9UzxtUm/X7GJO+EIUE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com; spf=pass smtp.mailfrom=163.com; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b=U5n41a6s; arc=none smtp.client-ip=117.135.210.5 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=163.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="U5n41a6s" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=Message-ID:Date:MIME-Version:Subject:From: Content-Type; bh=RFAmY2MKwdKHgLamuSXh1FUsHEdiYUg60MVKfaCdvoY=; b=U5n41a6szOt5DII0T5tNRMzSMBxAfvlaz7pd1kkkbJQ2ygpLyNRh27HYXcZSTV vL8FjA4B20MJ+/DYgoFSxHnELfuqfrOYDHt+LR6BaaIlcLzRs1vHuc9uQrgVItEt HkQ4DKQp6KKOhl81obXX6BAhTMMyYo+1zuMMJh3NJO6oU= Received: from [192.168.71.93] (unknown []) by gzga-smtp-mtada-g0-1 (Coremail) with SMTP id _____wCnwFuQjhtonhXNFA--.39420S2; Thu, 08 May 2025 00:47:13 +0800 (CST) Message-ID: Date: Thu, 8 May 2025 00:47:12 +0800 Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 3/3] PCI: aardvark: Remove redundant MPS configuration To: =?UTF-8?Q?Pali_Roh=C3=A1r?= , Niklas Cassel Cc: lpieralisi@kernel.org, kw@linux.com, bhelgaas@google.com, heiko@sntech.de, manivannan.sadhasivam@linaro.org, yue.wang@Amlogic.com, neil.armstrong@linaro.org, robh@kernel.org, jingoohan1@gmail.com, khilman@baylibre.com, jbrunet@baylibre.com, martin.blumenstingl@googlemail.com, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-amlogic@lists.infradead.org, linux-rockchip@lists.infradead.org References: <20250506173439.292460-1-18255117159@163.com> <20250506173439.292460-4-18255117159@163.com> <20250506174110.63ayeqc4scmwjj6e@pali> <8a6adc24-5f40-4f22-9842-b211e1ef5008@163.com> <20250507163620.53v5djmhj3ywrge2@pali> Content-Language: en-US From: Hans Zhang <18255117159@163.com> In-Reply-To: <20250507163620.53v5djmhj3ywrge2@pali> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-CM-TRANSID:_____wCnwFuQjhtonhXNFA--.39420S2 X-Coremail-Antispam: 1Uf129KBjvJXoWxuryxWFW7uF13Gw1kGr1fXrb_yoWruF4fpF W3XF4rAF47Jr15CF1Iq3Wvkry5tasrKry5XrZ8G343AF9Iqa45JFy2yr4rua47Xr4SkF12 yry5XrWIvFn0yaDanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07Um38nUUUUU= X-CM-SenderInfo: rpryjkyvrrlimvzbiqqrwthudrp/1tbiOgRGo2gbjGJKowAAsv On 2025/5/8 00:36, Pali Rohár wrote: > On Wednesday 07 May 2025 23:06:51 Hans Zhang wrote: >> On 2025/5/7 23:03, Hans Zhang wrote: >>> On 2025/5/7 01:41, Pali Rohár wrote: >>>> On Wednesday 07 May 2025 01:34:39 Hans Zhang wrote: >>>>> The Aardvark PCIe controller enforces a fixed 512B payload size via >>>>> PCI_EXP_DEVCTL_PAYLOAD_512B, overriding hardware capabilities and PCIe >>>>> core negotiations. >>>>> >>>>> Remove explicit MPS overrides (PCI_EXP_DEVCTL_PAYLOAD and >>>>> PCI_EXP_DEVCTL_PAYLOAD_512B). MPS is now determined by the PCI core >>>>> during device initialization, leveraging root port configurations and >>>>> device-specific capabilities. >>>>> >>>>> Aligning Aardvark with the unified MPS framework ensures consistency, >>>>> avoids artificial constraints, and allows the hardware to operate at >>>>> its maximum supported payload size while adhering to PCIe >>>>> specifications. >>>>> >>>>> Signed-off-by: Hans Zhang <18255117159@163.com> >>>>> --- >>>>>   drivers/pci/controller/pci-aardvark.c | 2 -- >>>>>   1 file changed, 2 deletions(-) >>>>> >>>>> diff --git a/drivers/pci/controller/pci-aardvark.c >>>>> b/drivers/pci/controller/pci-aardvark.c >>>>> index a29796cce420..d8852892994a 100644 >>>>> --- a/drivers/pci/controller/pci-aardvark.c >>>>> +++ b/drivers/pci/controller/pci-aardvark.c >>>>> @@ -549,9 +549,7 @@ static void advk_pcie_setup_hw(struct >>>>> advk_pcie *pcie) >>>>>       reg = advk_readl(pcie, PCIE_CORE_PCIEXP_CAP + PCI_EXP_DEVCTL); >>>>>       reg &= ~PCI_EXP_DEVCTL_RELAX_EN; >>>>>       reg &= ~PCI_EXP_DEVCTL_NOSNOOP_EN; >>>>> -    reg &= ~PCI_EXP_DEVCTL_PAYLOAD; >>>>>       reg &= ~PCI_EXP_DEVCTL_READRQ; >>>>> -    reg |= PCI_EXP_DEVCTL_PAYLOAD_512B; >>>>>       reg |= PCI_EXP_DEVCTL_READRQ_512B; >>>>>       advk_writel(pcie, reg, PCIE_CORE_PCIEXP_CAP + PCI_EXP_DEVCTL); >>>>> -- >>>>> 2.25.1 >>>>> >>>> >>>> Please do not remove this code. It is required part of the >>>> initialization of the aardvark PCI controller at the specific phase, >>>> as defined in the Armada 3700 Functional Specification. >>>> >>>> There were reported more issues with those Armada PCIe controllers for >>>> which were already sent patches to mailing list in last 5 years. But >>>> unfortunately not all fixes were taken / applied yet. >>> >>> Hi Pali, >>> >>> I replied to you in version v2. >>> >>> Is the maximum MPS supported by Armada 3700 512 bytes? > > IIRC yes, 512-byte mode is supported. And I think in past I was testing > some PCIe endpoint card which required 512-byte long payload and did not > worked in 256-byte long mode (not sure if the card was not able to split > transaction or something other was broken, it is quite longer time). > >>> What are the default values of DevCap.MPS and DevCtl.MPS? > > Do you mean values in the PCI-to-PCI bridge device of PCIe Root Port > type? > > Aardvark controller does not have the real HW PCI-to-PCI bridge device. > There is only in-kernel emulation drivers/pci/pci-bridge-emul.c which > create fake kernel PCI device in the hierarchy to make kernel and > userspace happy. Yes, this is deviation from the PCIe standard but well, > buggy HW is also HW. > > And same applies for the pci-mvebu.c driver for older Marvell PCIe HW. > >>> Because the default value of DevCtl.MPS is not 512 bytes, it needs to be >>> configured here, right? >>> >>> If it's my guess, RK3588 also has the same requirements as you, just >>> like the first patch I submitted. >>> >>> Please take a look at the communication history: >>> https://patchwork.kernel.org/project/linux-pci/patch/20250416151926.140202-1-18255117159@163.com/ >> And this: >> https://patchwork.kernel.org/project/linux-pci/patch/20250425095708.32662-2-18255117159@163.com/ > > These changes are referring the to root ports PCI devices, which are not > applicable for aardvark PCIe controller. > >>> >>> Please test it using patch 1/3 of this series. If there are any >>> problems, please let me know. >>> >>> >>> Best regards, >>> Hans >> > > Sorry, but I stopped doing any testing of the aardvark driver with the > mainline kernel after PCI maintainers stopped taking fixes for the > driver and stopped responding. > > I'm not going to debug same issues again, which I have analyzed, > prepared fixes, sent patches and see no progress there. > > Seems that there is a status quo, and I'm not going to change it. Dear Niklas, Do you have any opinion on Pali's reply? Should patch 3/3 be discarded? Beat regards, Hans