Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753126AbdFLXtc (ORCPT ); Mon, 12 Jun 2017 19:49:32 -0400 Received: from mail.kernel.org ([198.145.29.99]:42618 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752928AbdFLXta (ORCPT ); Mon, 12 Jun 2017 19:49:30 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3521223994 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=helgaas@kernel.org Date: Mon, 12 Jun 2017 18:49:24 -0500 From: Bjorn Helgaas To: Stefan Schoefegger Cc: linux-pci@vger.kernel.org, Richard Zhu , Arnd Bergmann , open list , Kishon Vijay Abraham I , Jingoo Han , Bjorn Helgaas , "moderated list:PCI DRIVER FOR IMX6" , Lucas Stach Subject: Re: [PATCH v2 1/1] PCI: imx6: Add pcie compliance test option Message-ID: <20170612234924.GE4379@bhelgaas-glaptop.roam.corp.google.com> References: <1472121518-9340-1-git-send-email-stefan.schoefegger@ginzinger.com> <1496835374-13053-1-git-send-email-stefan.schoefegger@ginzinger.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1496835374-13053-1-git-send-email-stefan.schoefegger@ginzinger.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2939 Lines: 81 On Wed, Jun 07, 2017 at 01:36:11PM +0200, Stefan Schoefegger wrote: > Link speed must not be limited to gen1 during link test for compliance > tests > > Signed-off-by: Stefan Schoefegger > --- > > Changes since v1: > - pci-imx6.c moved to dwc directory > > drivers/pci/dwc/Kconfig | 10 ++++++++++ > drivers/pci/dwc/pci-imx6.c | 21 ++++++++++++--------- > 2 files changed, 22 insertions(+), 9 deletions(-) > > diff --git a/drivers/pci/dwc/Kconfig b/drivers/pci/dwc/Kconfig > index b7e15526d676..b6e9ced5a45d 100644 > --- a/drivers/pci/dwc/Kconfig > +++ b/drivers/pci/dwc/Kconfig > @@ -77,6 +77,16 @@ config PCI_IMX6 > select PCIEPORTBUS > select PCIE_DW_HOST > > +config PCI_IMX6_COMPLIANCE_TEST > + bool "Enable pcie compliance tests on imx6" > + depends on PCI_IMX6 > + default n > + help > + Enables support for pcie compliance test on FSL iMX SoCs. > + The link speed wouldn't be limited to gen1 when enabled. > + Enable only during compliance tests, otherwise > + link detection will fail on some peripherals. I'm puzzled about why we would want to merge this patch. It looks like we're trying to game the system to make the device pass compliance testing when it isn't really compliant. Is this config option useful to users, or is it only useful during internal development of iMX SoCs? > config PCIE_SPEAR13XX > bool "STMicroelectronics SPEAr PCIe controller" > depends on PCI > diff --git a/drivers/pci/dwc/pci-imx6.c b/drivers/pci/dwc/pci-imx6.c > index 19a289b8cc94..b0fbe52e25b0 100644 > --- a/drivers/pci/dwc/pci-imx6.c > +++ b/drivers/pci/dwc/pci-imx6.c > @@ -533,15 +533,18 @@ static int imx6_pcie_establish_link(struct imx6_pcie *imx6_pcie) > u32 tmp; > int ret; > > - /* > - * Force Gen1 operation when starting the link. In case the link is > - * started in Gen2 mode, there is a possibility the devices on the > - * bus will not be detected at all. This happens with PCIe switches. > - */ > - tmp = dw_pcie_readl_dbi(pci, PCIE_RC_LCR); > - tmp &= ~PCIE_RC_LCR_MAX_LINK_SPEEDS_MASK; > - tmp |= PCIE_RC_LCR_MAX_LINK_SPEEDS_GEN1; > - dw_pcie_writel_dbi(pci, PCIE_RC_LCR, tmp); > + if (!IS_ENABLED(CONFIG_PCI_IMX6_COMPLIANCE_TEST)) { > + /* > + * Force Gen1 operation when starting the link. In case the > + * link is started in Gen2 mode, there is a possibility the > + * devices on the bus will not be detected at all. This > + * happens with PCIe switches. > + */ > + tmp = dw_pcie_readl_dbi(pci, PCIE_RC_LCR); > + tmp &= ~PCIE_RC_LCR_MAX_LINK_SPEEDS_MASK; > + tmp |= PCIE_RC_LCR_MAX_LINK_SPEEDS_GEN1; > + dw_pcie_writel_dbi(pci, PCIE_RC_LCR, tmp); > + } > > /* Start LTSSM. */ > if (imx6_pcie->variant == IMX7D) > -- > 2.11.0 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel