From patchwork Tue Oct 11 04:26:25 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Shawn Lin X-Patchwork-Id: 9370105 X-Patchwork-Delegate: bhelgaas@google.com 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 2A14E60487 for ; Tue, 11 Oct 2016 04:21:07 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1E39928D62 for ; Tue, 11 Oct 2016 04:21:07 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 1309A29A19; Tue, 11 Oct 2016 04:21:07 +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=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B5B0429536 for ; Tue, 11 Oct 2016 04:21:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752002AbcJKEU7 (ORCPT ); Tue, 11 Oct 2016 00:20:59 -0400 Received: from lucky1.263xmail.com ([211.157.147.132]:34630 "EHLO lucky1.263xmail.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751437AbcJKEU7 (ORCPT ); Tue, 11 Oct 2016 00:20:59 -0400 Received: from shawn.lin?rock-chips.com (unknown [192.168.167.175]) by lucky1.263xmail.com (Postfix) with ESMTP id 7779B63679; Tue, 11 Oct 2016 12:20:21 +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 57ED4384; Tue, 11 Oct 2016 12:20:20 +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 277972QVJB2; Tue, 11 Oct 2016 12:20:21 +0800 (CST) From: Shawn Lin To: Bjorn Helgaas , Rob Herring Cc: linux-pci@vger.kernel.org, linux-rockchip@lists.infradead.org, Rajat Jain , Wenrui Li , Brian Norris , devicetree@vger.kernel.org, Shawn Lin Subject: [PATCH v6 1/3] Documentation/devicetree: Add new property to specify the max link speed Date: Tue, 11 Oct 2016 12:26:25 +0800 Message-Id: <1476159987-31372-1-git-send-email-shawn.lin@rock-chips.com> X-Mailer: git-send-email 1.8.0 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.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 --- 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.