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: 13633594 X-Patchwork-Delegate: kw@linux.com 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 CA70E12C819; Wed, 17 Apr 2024 16:42:34 +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=1713372154; cv=none; b=CAvLZpTks2H+PDWuUJzh9ZQhjzQfeWmRd4jTVk704o6he11dZ7hpnz2xRzpknhEnnBRPuMbDvrAfDI+SSWvDE+d1KLSeZqW4kZNEspZVoiZOAUmCWZhwffnhJD2fhE2VpY5my3RucGwAPnzS+l9GCT7NBn1F2+6d/w6Qd/G/RGY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713372154; c=relaxed/simple; bh=bFAV0Ws7047o+4oNJQ9VEZqnv8b/ertE1ngvFBcZ5F8=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=poCi3OqVVl4u+eU7OI4/As9C+gLtgXCqUdgVbU2t24E8549vg3k6EnZJyhxxUUanoqXaK2D8u+gChwrzzQiqJkdUYz7P8979cryJK/b1hN2zjhlikUhAnJmJD8E2J3hbrQ2q7yiXl9vweRZ7C54IvhSDs7aHx73dLwJLWtN6imA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=TBwFRqeM; 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="TBwFRqeM" 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 Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 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);