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 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 B761EC6FD1F for ; Sat, 30 Mar 2024 03:51:09 +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=Mr4Gh3PoufK+I9YT6T3W1xC53S9FUGNowBu2SzdPr+8=; b=W27/gwYOwG0Oie 2CcjnZUFpOyvM+GuSSKAldXne3ZlEMKdxSlEQMn+inSIbcViugEyCE6rFb0H5CCQNI9DQ5AuzQs16 /CWBXYzD4l07IzP7tzu0fbR/xPdkHwwbkbgseOHmCWCYVkMlQaC18346Tdqs7PVxnQK8Y+YlrmutD um6SX0Kb2wi5+dSGielj9UNCNpuSpdZWn3ng5bl1bRMFykGUYWqHx+Hicknf0HodrTveWEnZnM2cB GW2pkXvM8QyM6hIoiv2ZCqiyDcyVlT7NJZVUUYo9HWB4Hv5SyRkZ+sNgSqIy5dhEZk7dkeBO7kXOa KQJ8Z7Z46T/b+ZujvAXg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rqPk6-00000002gry-0Xtk; Sat, 30 Mar 2024 03:50:54 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1rqPjy-00000002gqz-1SZh; Sat, 30 Mar 2024 03:50:47 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id B5427618B4; Sat, 30 Mar 2024 03:50:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4B46FC433C7; Sat, 30 Mar 2024 03:50:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1711770645; bh=9vfnCaBKXtRgcv8F/e2Tdm9el/hk1aeDzoQ8fr5kZVQ=; h=From:To:Cc:Subject:Date:From; b=uQA6GcFPKYREp76Y3XplqgC946g7Qj2DQ5d0cxAX0A65rXq457pclwXd8q9/b3ruC rxPd0RTlXTBqT4GOQ5h0UNp5T+62XgIEXKGtyBlpo78SEJBODeWhO6KdxlKnnFs+Tc jJEOKe7IUgFjgHiGdEubAwXzf3Hlg3vNoprDtzQSZq+rq/t6GUTHMGcsezRDoDGidJ k5Hq/D8o2QZz+o6Na4MEbmXqy7aLQoPNRxCICMdnMWWbqwsDSwNBUeya+SnrUpIrad IPXbPYDwAZtsXYpt+3VB32bDo93snv9LB5rZkmKi2i8HSD8+DzPdB/M+jvG6yzrDyv /0Q1J3xPFGg7w== From: Damien Le Moal To: Shawn Lin , Bjorn Helgaas , Heiko Stuebner , linux-pci@vger.kernel.org Cc: Lorenzo Pieralisi , =?UTF-8?q?Krzysztof=20Wilczy=C5=84ski?= , linux-rockchip@lists.infradead.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH v2] PCI: rockchip-host: Fix rockchip_pcie_host_init_port() PERST# handling Date: Sat, 30 Mar 2024 12:50:43 +0900 Message-ID: <20240330035043.1546087-1-dlemoal@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-20240329_205046_483960_F2B15A19 X-CRM114-Status: GOOD ( 11.02 ) 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org The PCIe specifications (PCI Express Electromechanical Specification rev 2.0, section 2.6.2) mandate that the PERST# signal must remain asserted for at least 100 usec (Tperst-clk) after the PCIe reference clock becomes stable (if a reference clock is supplied), for at least 100 msec after the power is stable (Tpvperl). In addition, the PCI Express Base SPecification Rev 2.0, section 6.6.1 state that the host should wait for at least 100 msec from the end of a conventional reset (PERST# is de-asserted) before accessing the configuration space of the attached device. Modify rockchip_pcie_host_init_port() by adding two 100ms sleep, one before and after bringing back PESRT signal to high using the ep_gpio GPIO. Comments are also added to clarify this behavior. Signed-off-by: Damien Le Moal --- Changes from v1: - Add more specification details to the commit message. - Add missing msleep(100) after PERST# is deasserted. drivers/pci/controller/pcie-rockchip-host.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/pci/controller/pcie-rockchip-host.c b/drivers/pci/controller/pcie-rockchip-host.c index 300b9dc85ecc..ff2fa27bd883 100644 --- a/drivers/pci/controller/pcie-rockchip-host.c +++ b/drivers/pci/controller/pcie-rockchip-host.c @@ -294,6 +294,7 @@ static int rockchip_pcie_host_init_port(struct rockchip_pcie *rockchip) int err, i = MAX_LANE_NUM; u32 status; + /* Assert PERST */ gpiod_set_value_cansleep(rockchip->ep_gpio, 0); err = rockchip_pcie_init_port(rockchip); @@ -322,8 +323,19 @@ static int rockchip_pcie_host_init_port(struct rockchip_pcie *rockchip) rockchip_pcie_write(rockchip, PCIE_CLIENT_LINK_TRAIN_ENABLE, PCIE_CLIENT_CONFIG); + /* + * PCIe CME specifications mandate that PERST be asserted for at + * least 100ms after power is stable. + */ + msleep(100); gpiod_set_value_cansleep(rockchip->ep_gpio, 1); + /* + * PCIe base specifications rev 2.0 mandate that the host wait for + * 100ms after completion of a conventional reset. + */ + msleep(100); + /* 500ms timeout value should be enough for Gen1/2 training */ err = readl_poll_timeout(rockchip->apb_base + PCIE_CLIENT_BASIC_STATUS1, status, PCIE_LINK_UP(status), 20, -- 2.44.0 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel