From patchwork Tue Oct 18 01:45:08 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Shawn Lin X-Patchwork-Id: 9381001 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 1F05560487 for ; Tue, 18 Oct 2016 01:39:46 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 12FC128CBC for ; Tue, 18 Oct 2016 01:39:46 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 076BF291A0; Tue, 18 Oct 2016 01:39:46 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 8AD3228CBC for ; Tue, 18 Oct 2016 01:39:45 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.85_2 #1 (Red Hat Linux)) id 1bwJNZ-0001g3-7h; Tue, 18 Oct 2016 01:39:45 +0000 Received: from lucky1.263xmail.com ([211.157.147.134]) by bombadil.infradead.org with esmtps (Exim 4.85_2 #1 (Red Hat Linux)) id 1bwJNW-0001bk-C9 for linux-rockchip@lists.infradead.org; Tue, 18 Oct 2016 01:39:43 +0000 Received: from shawn.lin?rock-chips.com (unknown [192.168.167.87]) by lucky1.263xmail.com (Postfix) with ESMTP id 2117381D; Tue, 18 Oct 2016 09:39:20 +0800 (CST) X-263anti-spam: KSV:0; X-MAIL-GRAY: 1 X-MAIL-DELIVERY: 0 X-KSVirus-check: 0 X-ABS-CHECKED: 4 X-ADDR-CHECKED4: 1 Received: from localhost.localdomain (localhost [127.0.0.1]) by smtp.263.net (Postfix) with ESMTP id ED4733EE; Tue, 18 Oct 2016 09:39:17 +0800 (CST) X-RL-SENDER: shawn.lin@rock-chips.com X-FST-TO: bhelgaas@google.com X-SENDER-IP: 58.22.7.114 X-LOGIN-NAME: shawn.lin@rock-chips.com X-UNIQUE-TAG: X-ATTACHMENT-NUM: 0 X-SENDER: lintao@rock-chips.com X-DNS-TYPE: 0 Received: from localhost.localdomain (unknown [58.22.7.114]) by smtp.263.net (Postfix) whith ESMTP id 738828I7KJ; Tue, 18 Oct 2016 09:39:19 +0800 (CST) From: Shawn Lin To: Bjorn Helgaas , Rob Herring Subject: [PATCH v8 1/3] Documentation/devicetree: Add new property to specify the max link speed Date: Tue, 18 Oct 2016 09:45:08 +0800 Message-Id: <1476755110-22647-1-git-send-email-shawn.lin@rock-chips.com> X-Mailer: git-send-email 1.8.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20161017_183942_844053_3173767D X-CRM114-Status: UNSURE ( 5.75 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-rockchip@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Upstream kernel work for Rockchip platforms List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: devicetree@vger.kernel.org, Wenrui Li , linux-pci@vger.kernel.org, Shawn Lin , Brian Norris , linux-rockchip@lists.infradead.org MIME-Version: 1.0 Sender: "Linux-rockchip" Errors-To: linux-rockchip-bounces+patchwork-linux-rockchip=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP Some of the host drivers have the requirement of knowing whether the EP would never train at some link speed at all. For instance, on some boards, the link won't train at 5 GT/s but the host driver still sacrifice some cycle to wait for the resule of training at 5 GT/s as the host could actually support 5 GT/s. So we could parse this new property and make the host drivers be aware of these cases. Signed-off-by: Shawn Lin Acked-by: Rob Herring --- Changes in v8: None Changes in v7: None Changes in v6: None Changes in v5: None Changes in v4: None Changes in v3: None Changes in v2: None Documentation/devicetree/bindings/pci/pci.txt | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/Documentation/devicetree/bindings/pci/pci.txt b/Documentation/devicetree/bindings/pci/pci.txt index 08dcfad..e7d97a3 100644 --- a/Documentation/devicetree/bindings/pci/pci.txt +++ b/Documentation/devicetree/bindings/pci/pci.txt @@ -18,3 +18,9 @@ driver implementation may support the following properties: host bridges in the system, otherwise potentially conflicting domain numbers may be assigned to root buses behind different host bridges. The domain number for each host bridge in the system must be unique. +- max-link-speed: + If present this property specifies PCI gen for link capability. The host drivers + could add this as a strategy to avoid unnecessary operation for unsupported + link speed, for instance, trying to do training for unsupported link speed, etc. + Must be '4' for gen4, '3' for gen3, '2' for gen2, and '1' for gen1. Any other + values are invalid.