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 X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3B7E8C282CE for ; Wed, 22 May 2019 21:26:49 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id D4B7220821 for ; Wed, 22 May 2019 21:26:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="DGaU5NVE" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D4B7220821 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=triplefau.lt Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-Id:Date:Subject: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=Qper+IXtaqYCJoIJ+w6i7OYTfziUTXdPFxSHjPCqU7U=; b=DGaU5NVEzAzbmC xXo1lnQgSfFUO7VwHNvwqQSkzWO+AC9JjjoChn6aLCvlNRIDj2LLcNrA3VSxR9o2V0W0qkJWK1i5C 5x4I4xGMqL0bXK+bS9OzX76zSxLjc+xxi4s12ix2txrPTWC6eUH3awep7UIWdL+KcKYGFCmJ3RVZk QW1h92RE7UThqgl9WlxI0n5PrDz96o48fHovnV2mtPWP8ZUBFbaRRXILhCoCSzuFyIbDspXzTYMb+ kLP6FpCq7Nwf8g1ZZEkXwA2eBs9bpT4SC47OpiQToceO6Y8zJnI9XJE/tEuuYIitNA42ObUvRG+S2 8n6UWu6gQ98Z6jPpcFlg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hTYl1-0007rO-4C; Wed, 22 May 2019 21:26:43 +0000 Received: from relay9-d.mail.gandi.net ([217.70.183.199]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1hTYky-0007pF-0Z for linux-arm-kernel@lists.infradead.org; Wed, 22 May 2019 21:26:41 +0000 X-Originating-IP: 88.190.179.123 Received: from localhost (unknown [88.190.179.123]) (Authenticated sender: repk@triplefau.lt) by relay9-d.mail.gandi.net (Postfix) with ESMTPSA id 5D16DFF805; Wed, 22 May 2019 21:26:25 +0000 (UTC) From: Remi Pommarel To: Thomas Petazzoni , Lorenzo Pieralisi , Bjorn Helgaas Subject: [PATCH v2] PCI: aardvark: Wait for endpoint to be ready before training link Date: Wed, 22 May 2019 23:33:50 +0200 Message-Id: <20190522213351.21366-2-repk@triplefau.lt> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190522_142640_202063_E049C528 X-CRM114-Status: UNSURE ( 9.17 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-pci@vger.kernel.org, Ellie Reeves , Remi Pommarel , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org When configuring pcie reset pin from gpio (e.g. initially set by u-boot) to pcie function this pin goes low for a brief moment asserting the PERST# signal. Thus connected device enters fundamental reset process and link configuration can only begin after a minimal 100ms delay (see [1]). Because the pin configuration comes from the "default" pinctrl it is implicitly configured before the probe callback is called: driver_probe_device() really_probe() ... pinctrl_bind_pins() /* Here pin goes from gpio to PCIE reset function and PERST# is asserted */ ... drv->probe() [1] "PCI Express Base Specification", REV. 4.0 PCI Express, February 19 2014, 6.6.1 Conventional Reset Signed-off-by: Remi Pommarel --- Changes since v1: - Add a comment about pinctrl implicit pin configuration - Use more legible msleep - Use PCI_PM_D3COLD_WAIT macro Please note that I will unlikely be able to answer any comments from May 24th to June 10th. --- drivers/pci/controller/pci-aardvark.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c index 134e0306ff00..d998c2b9cd04 100644 --- a/drivers/pci/controller/pci-aardvark.c +++ b/drivers/pci/controller/pci-aardvark.c @@ -324,6 +324,14 @@ static void advk_pcie_setup_hw(struct advk_pcie *pcie) reg |= PIO_CTRL_ADDR_WIN_DISABLE; advk_writel(pcie, reg, PIO_CTRL); + /* + * PERST# signal could have been asserted by pinctrl subsystem before + * probe() callback has been called, making the endpoint going into + * fundamental reset. As required by PCI Express spec a delay for at + * least 100ms after such a reset before link training is needed. + */ + msleep(PCI_PM_D3COLD_WAIT); + /* Start link training */ reg = advk_readl(pcie, PCIE_CORE_LINK_CTRL_STAT_REG); reg |= PCIE_CORE_LINK_TRAINING; -- 2.20.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel