From patchwork Fri Apr 24 15:38:51 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Pali_Roh=C3=A1r?= X-Patchwork-Id: 1276446 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=linux-pci-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=kernel.org Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=default header.b=T49/CS+p; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 497yyh5vxnz9sRf for ; Sat, 25 Apr 2020 01:39:24 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728518AbgDXPjT (ORCPT ); Fri, 24 Apr 2020 11:39:19 -0400 Received: from mail.kernel.org ([198.145.29.99]:36628 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728524AbgDXPjT (ORCPT ); Fri, 24 Apr 2020 11:39:19 -0400 Received: from pali.im (pali.im [31.31.79.79]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4E46721569; Fri, 24 Apr 2020 15:39:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587742758; bh=X2+JV0oDgncx/VEQRHXbQ1ayRkCQmmFc+ktcFpbVES0=; h=From:To:Subject:Date:In-Reply-To:References:From; b=T49/CS+p0bP6GEZDqEOBeFUP7eTGqLMmxgUDV6RUHV1pNZc4mqsKIe2s5Jrtd3fpx 1mOixvAZjFNCZRlhjHo8GWMH5zcSccVsZj5gb+VQXI3z3qHOg+mhigf39Y1Og3xsWt 5+7ZuRl69eGzbvGbRcJI2WIULAGDUcq0IV7Ecuiw= Received: by pali.im (Postfix) id 82035A05; Fri, 24 Apr 2020 17:39:16 +0200 (CEST) From: =?utf-8?q?Pali_Roh=C3=A1r?= To: linux-pci@vger.kernel.org, Jason Cooper , Andrew Lunn , Gregory Clement , Sebastian Hesselbarth , Thomas Petazzoni , Lorenzo Pieralisi , Andrew Murray , Remi Pommarel , Tomasz Maciej Nowak , Xogium , Rob Herring , =?utf-8?q?Marek_?= =?utf-8?q?Beh=C3=BAn?= , Bjorn Helgaas Subject: [PATCH v3 05/12] PCI: aardvark: Issue PERST via GPIO Date: Fri, 24 Apr 2020 17:38:51 +0200 Message-Id: <20200424153858.29744-6-pali@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200424153858.29744-1-pali@kernel.org> References: <20200424153858.29744-1-pali@kernel.org> MIME-Version: 1.0 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Add support for issuing PERST via GPIO specified in 'reset-gpios' property (as described in PCI device tree bindings). Some buggy cards (e.g. Compex WLE900VX or WLE1216) are not detected after reboot when PERST is not issued during driver initialization. If bootloader already enabled link training then issuing PERST has no effect for some buggy cards (e.g. Compex WLE900VX) and these cards are not detected. We therefore clear the LINK_TRAINING_EN register before. It was observed that Compex WLE900VX card needs to be in PERST reset for at least 10ms if bootloader enabled link training. Tested on Turris MOX. Signed-off-by: Pali Rohár --- drivers/pci/controller/pci-aardvark.c | 43 ++++++++++++++++++++++++++- 1 file changed, 42 insertions(+), 1 deletion(-) diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c index a6c4d4d52631..9e2f44213b5e 100644 --- a/drivers/pci/controller/pci-aardvark.c +++ b/drivers/pci/controller/pci-aardvark.c @@ -9,6 +9,7 @@ */ #include +#include #include #include #include @@ -18,6 +19,7 @@ #include #include #include +#include #include #include "../pci.h" @@ -204,6 +206,7 @@ struct advk_pcie { int root_bus_nr; int link_gen; struct pci_bridge_emul bridge; + struct gpio_desc *reset_gpio; }; static inline void advk_writel(struct advk_pcie *pcie, u32 val, u64 reg) @@ -330,10 +333,31 @@ static void advk_pcie_train_link(struct advk_pcie *pcie) dev_err(dev, "link never came up\n"); } +static void advk_pcie_issue_perst(struct advk_pcie *pcie) +{ + u32 reg; + + if (!pcie->reset_gpio) + return; + + /* PERST does not work for some cards when link training is enabled */ + reg = advk_readl(pcie, PCIE_CORE_CTRL0_REG); + reg &= ~LINK_TRAINING_EN; + advk_writel(pcie, reg, PCIE_CORE_CTRL0_REG); + + /* 10ms delay is needed for some cards */ + dev_info(&pcie->pdev->dev, "issuing PERST via reset GPIO for 10ms\n"); + gpiod_set_value_cansleep(pcie->reset_gpio, 1); + usleep_range(10000, 11000); + gpiod_set_value_cansleep(pcie->reset_gpio, 0); +} + static void advk_pcie_setup_hw(struct advk_pcie *pcie) { u32 reg; + advk_pcie_issue_perst(pcie); + /* Set to Direct mode */ reg = advk_readl(pcie, CTRL_CONFIG_REG); reg &= ~(CTRL_MODE_MASK << CTRL_MODE_SHIFT); @@ -406,7 +430,8 @@ static void advk_pcie_setup_hw(struct advk_pcie *pcie) /* * PERST# signal could have been asserted by pinctrl subsystem before - * probe() callback has been called, making the endpoint going into + * probe() callback has been called or issued explicitly by reset gpio + * function advk_pcie_issue_perst(), 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. */ @@ -1046,6 +1071,22 @@ static int advk_pcie_probe(struct platform_device *pdev) } pcie->root_bus_nr = bus->start; + pcie->reset_gpio = devm_gpiod_get_from_of_node(dev, dev->of_node, + "reset-gpios", 0, + GPIOD_OUT_LOW, + "pcie1-reset"); + ret = PTR_ERR_OR_ZERO(pcie->reset_gpio); + if (ret) { + if (ret == -ENOENT) { + pcie->reset_gpio = NULL; + } else { + if (ret != -EPROBE_DEFER) + dev_err(dev, "Failed to get reset-gpio: %i\n", + ret); + return ret; + } + } + ret = of_pci_get_max_link_speed(dev->of_node); if (ret < 0) return ret;