From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 E0D0979F6; Sun, 17 Nov 2024 08:00:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731830446; cv=none; b=UaK6H4CGFCo8d5aJnrjVF654k1aP1hgvvop+Q3HgOMOgF66reaDUDuvOumecRKPaOSbHJ0FD2YdRrFxth3MNtlfkfmJbMAd6UhnlfWzws2VvPgLR/SAgMohZWEJNgCCuylYG68dEPSZrT+k24X9xtnKEFjFsdFm9Jy6dBpzLzuI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731830446; c=relaxed/simple; bh=yG/Prvv2cW4FAbQIxSEqLgZUGZ3kv80l7NsNSnpg53M=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=kY5a7g4NLGRWkDPP9uMPw+yVLKca778Jvir1FQhlnU4kQYytLwIwzoHU4qM6gzbWcPwd5hXACZvbhtt8jWp35F8hVOAlXSugnB2BgszWD14457Y/klwwXc6+loWLp9la8ILCqcuPKdx0cFGToArHKV7ayUZQmMm35gQUC3QvhW8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Gqfs5s6y; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Gqfs5s6y" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7AB0FC4CECD; Sun, 17 Nov 2024 08:00:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1731830445; bh=yG/Prvv2cW4FAbQIxSEqLgZUGZ3kv80l7NsNSnpg53M=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=Gqfs5s6yPfPvpIR/sBXHis0a0AI5ejKOd74ZA3OIxcF77rHXSmvJu6tZGO5WjO2sp VI8Ds5IkGhecdxwAIcTLz4Ii1blB06aUeab/Af7dijufr/PetogT+B1f3+IoC9doIP 3rBc/91TRUKN/Yysf1UEKuVllyeahSzksv5EiaLsZZhz+9Ly07mlMyl+OsTzRShHm5 X8V8KYQUq8Ck4WDOuIses5VrALQ7Vb1T6Gbdf8qWLXCGzJD6jL9tlTlV3bsKx4J4cG gC65Sjr5DkIrvv2vzMS8kW9StasNCjgdW+gZm0GBTokQWSjJwjZBZ87GgML4RsUhhX 7CDgY4aUilWUA== Message-ID: <8393e56d-8ba1-436d-ad97-ec44893d2f6f@kernel.org> Date: Sun, 17 Nov 2024 17:00:42 +0900 Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 12/14] PCI: rockchip-ep: Improve link training To: Bjorn Helgaas Cc: Manivannan Sadhasivam , Lorenzo Pieralisi , Kishon Vijay Abraham I , Shawn Lin , =?UTF-8?Q?Krzysztof_Wilczy=C5=84ski?= , Bjorn Helgaas , linux-pci@vger.kernel.org, Rob Herring , Krzysztof Kozlowski , Conor Dooley , Heiko Stuebner , devicetree@vger.kernel.org, linux-rockchip@lists.infradead.org, Rick Wertenbroek , Niklas Cassel References: <20241115230319.GA2065576@bhelgaas> From: Damien Le Moal Content-Language: en-US Organization: Western Digital Research In-Reply-To: <20241115230319.GA2065576@bhelgaas> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 11/16/24 08:03, Bjorn Helgaas wrote: > On Thu, Oct 17, 2024 at 10:58:47AM +0900, Damien Le Moal wrote: >> The Rockchip RK3399 TRM V1.3 Part2, Section 17.5.8.1.2, step 7, >> describes the endpoint mode link training process clearly and states >> that: >> Insure link training completion and success by observing link_st field >> in PCIe Client BASIC_STATUS1 register change to 2'b11. If both side >> support PCIe Gen2 speed, re-train can be Initiated by asserting the >> Retrain Link field in Link Control and Status Register. The software >> should insure the BASIC_STATUS0[negotiated_speed] changes to "1", that >> indicates re-train to Gen2 successfully. > > Since this only adds code and doesn't change existing code, I assume > this hardware doesn't automatically train to gen2 without this new > software assistance? > > So the effect of this change is to use gen2 speed when supported by > both partners, when previously we only got gen1? Yes. The host side has something similar as well. -- Damien Le Moal Western Digital Research