From patchwork Wed Apr 17 16:42:26 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Niklas Cassel X-Patchwork-Id: 13633613 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 7D372C4345F for ; Wed, 17 Apr 2024 16:42:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-ID:Date:Subject:Cc :To:From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=ryAIjQ0/MPSmBFtAADtW3OPaiUaGr9BTkq4HSFAi/L0=; b=fexSjaqRIm1Qsx h5JF0k0rqArLQRYBTa/rKuUi6xz4IAVtmQ6J3U86kZpeMAC7DEMoRRJ2VpoxfEg8MZGouFTZVXINs e/QJPP6MSV270TeAmiv1nQszFYJLyz8vNfTWNU8JuWgUXqrxGxOOyRFnCitdnyjyWka31Pd3f61vv a0s18V2h2PZFD1tiuUjuNnyBu8kyR311mgJLmpEKVvykeZC9981Nvn9F8+kibjiOHZuJwb6BgSxCn HPPuIaU7I2qXsN9OVOsIhIuNer0eqWls9ABwvbjV+LcDKArL/5UfQXDY+4Cb2zQ4X+qKuMsTbAZ57 9mMR/LUWF/qkxY4fClRg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rx8Mp-0000000Gqy6-192c; Wed, 17 Apr 2024 16:42:39 +0000 Received: from dfw.source.kernel.org ([139.178.84.217]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1rx8Ml-0000000GqxQ-2erE; Wed, 17 Apr 2024 16:42:36 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id BA647614FC; Wed, 17 Apr 2024 16:42:34 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 36E26C072AA; Wed, 17 Apr 2024 16:42:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1713372154; bh=bFAV0Ws7047o+4oNJQ9VEZqnv8b/ertE1ngvFBcZ5F8=; h=From:To:Cc:Subject:Date:From; b=TBwFRqeMg7Ol1u9QdhO34wpSKv7pLxDHJHtAELzYbIp83gCMM9ocBL3jxlaZifLtN mUNC+O9HXbY3nBTWFp1nmnJkNCkRxNL6a5iTVdaiO0W6sYUDAuew/kiccCdkyRmMo7 p/V2C5FywN04TaQ0w68KK8UtdFIOPx80cYut1oIZw2k0idf1YCOjEmqNrHYtzsu69r wni2xPLCvJ50i+pU5Aa1GMz0sofNT/2YPMiM202+aQKPCcQ2s3TrK2Nwh5RhQ2rDuW mqIexugp3M8ScTz+p8mKODdGF074M0Tp1wU1YFKb5VkaYgYSg6W1RSgmlPwMzQ5JrM JyA4K+jf2g8eQ== From: Niklas Cassel To: Lorenzo Pieralisi , =?utf-8?q?Krzysztof_Wilczy?= =?utf-8?q?=C5=84ski?= , Rob Herring , Bjorn Helgaas , Heiko Stuebner , Simon Xue , Kever Yang Cc: Damien Le Moal , Niklas Cassel , Jianfeng Liu , Manivannan Sadhasivam , stable@vger.kernel.org, linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org Subject: [PATCH v3] PCI: dw-rockchip: Fix initial PERST# GPIO value Date: Wed, 17 Apr 2024 18:42:26 +0200 Message-ID: <20240417164227.398901-1-cassel@kernel.org> X-Mailer: git-send-email 2.44.0 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240417_094235_777407_382FB8D6 X-CRM114-Status: GOOD ( 11.79 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org PERST# is active low according to the PCIe specification. However, the existing pcie-dw-rockchip.c driver does: gpiod_set_value(..., 0); msleep(100); gpiod_set_value(..., 1); When asserting + deasserting PERST#. This is of course wrong, but because all the device trees for this compatible string have also incorrectly marked this GPIO as ACTIVE_HIGH: $ git grep -B 10 reset-gpios arch/arm64/boot/dts/rockchip/rk3568* $ git grep -B 10 reset-gpios arch/arm64/boot/dts/rockchip/rk3588* The actual toggling of PERST# is correct. (And we cannot change it anyway, since that would break device tree compatibility.) However, this driver does request the GPIO to be initialized as GPIOD_OUT_HIGH, which does cause a silly sequence where PERST# gets toggled back and forth for no good reason. Fix this by requesting the GPIO to be initialized as GPIOD_OUT_LOW (which for this driver means PERST# asserted). This will avoid an unnecessary signal change where PERST# gets deasserted (by devm_gpiod_get_optional()) and then gets asserted (by rockchip_pcie_start_link()) just a few instructions later. Before patch, debug prints on EP side, when booting RC: [ 845.606810] pci: PERST# asserted by host! [ 852.483985] pci: PERST# de-asserted by host! [ 852.503041] pci: PERST# asserted by host! [ 852.610318] pci: PERST# de-asserted by host! After patch, debug prints on EP side, when booting RC: [ 125.107921] pci: PERST# asserted by host! [ 132.111429] pci: PERST# de-asserted by host! This extra, very short, PERST# assertion + deassertion has been reported to cause issues with certain WLAN controllers, e.g. RTL8822CE. Fixes: 0e898eb8df4e ("PCI: rockchip-dwc: Add Rockchip RK356X host controller driver") Tested-by: Jianfeng Liu Tested-by: Heiko Stuebner Signed-off-by: Niklas Cassel Reviewed-by: Manivannan Sadhasivam Cc: stable@vger.kernel.org # 5.15+ Reviewed-by: Heiko Stuebner --- Changes since v2: -Picked up tag from Heiko. -Change subject (Bjorn). -s/PERST/PERST#/ (Bjorn). drivers/pci/controller/dwc/pcie-dw-rockchip.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/pci/controller/dwc/pcie-dw-rockchip.c b/drivers/pci/controller/dwc/pcie-dw-rockchip.c index d6842141d384..a909e42b4273 100644 --- a/drivers/pci/controller/dwc/pcie-dw-rockchip.c +++ b/drivers/pci/controller/dwc/pcie-dw-rockchip.c @@ -240,7 +240,7 @@ static int rockchip_pcie_resource_get(struct platform_device *pdev, return PTR_ERR(rockchip->apb_base); rockchip->rst_gpio = devm_gpiod_get_optional(&pdev->dev, "reset", - GPIOD_OUT_HIGH); + GPIOD_OUT_LOW); if (IS_ERR(rockchip->rst_gpio)) return PTR_ERR(rockchip->rst_gpio);