From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751238AbdFASLe (ORCPT ); Thu, 1 Jun 2017 14:11:34 -0400 Received: from mail-qt0-f180.google.com ([209.85.216.180]:33726 "EHLO mail-qt0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751122AbdFASLd (ORCPT ); Thu, 1 Jun 2017 14:11:33 -0400 Subject: Re: [PATCH 2/2] PCI: iproc: add device shutdown for PCI RC To: Oza Pawandeep , Bjorn Helgaas , Ray Jui , Scott Branden , Jon Mason , bcm-kernel-feedback-list@broadcom.com, Andy Gospodarek , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Oza Pawandeep References: <1496294871-5836-1-git-send-email-oza.oza@broadcom.com> <1496294871-5836-3-git-send-email-oza.oza@broadcom.com> From: Ray Jui Message-ID: <397e2b1a-c62f-2df2-5eca-8e240ac65df5@broadcom.com> Date: Thu, 1 Jun 2017 11:11:24 -0700 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:54.0) Gecko/20100101 Thunderbird/54.0 MIME-Version: 1.0 In-Reply-To: <1496294871-5836-3-git-send-email-oza.oza@broadcom.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Oza, On 5/31/17 10:27 PM, Oza Pawandeep wrote: > PERST# must be asserted around ~500ms before > the reboot is applied. > > During soft reset (e.g., "reboot" from Linux) on some iProc based SoCs > LCPLL clock and PERST both goes off simultaneously. > This will cause certain Endpoints Intel NVMe not get detected, upon > next boot sequence. > > This happens because; Endpoint is expecting the clock for some amount of > time after PERST is asserted, which is not happening in our case > (Compare to Intel X86 boards, will have clocks running). > this cause NVMe to behave in undefined way. > > Essentially clock will remain alive for 500ms with PERST# = 0 > before reboot. > > This patch adds platform shutdown where it should be > called in device_shutdown while reboot command is issued. > > So in sequence first Endpoint Shutdown (e.g. nvme_shutdown) > followed by RC shutdown is called, which issues safe PERST > assertion. > > Signed-off-by: Oza Pawandeep > Reviewed-by: Ray Jui > Reviewed-by: Scott Branden > > diff --git a/drivers/pci/host/pcie-iproc-platform.c b/drivers/pci/host/pcie-iproc-platform.c > index 90d2bdd..9512960 100644 > --- a/drivers/pci/host/pcie-iproc-platform.c > +++ b/drivers/pci/host/pcie-iproc-platform.c > @@ -131,6 +131,13 @@ static int iproc_pcie_pltfm_remove(struct platform_device *pdev) > return iproc_pcie_remove(pcie); > } > > +static void iproc_pcie_pltfm_shutdown(struct platform_device *pdev) > +{ > + struct iproc_pcie *pcie = platform_get_drvdata(pdev); > + > + iproc_pcie_shutdown(pcie); > +} > + > static struct platform_driver iproc_pcie_pltfm_driver = { > .driver = { > .name = "iproc-pcie", > @@ -138,6 +145,7 @@ static int iproc_pcie_pltfm_remove(struct platform_device *pdev) > }, > .probe = iproc_pcie_pltfm_probe, > .remove = iproc_pcie_pltfm_remove, > + .shutdown = iproc_pcie_pltfm_shutdown, > }; > module_platform_driver(iproc_pcie_pltfm_driver); > > diff --git a/drivers/pci/host/pcie-iproc.c b/drivers/pci/host/pcie-iproc.c > index 05a3647..e9afc63 100644 > --- a/drivers/pci/host/pcie-iproc.c > +++ b/drivers/pci/host/pcie-iproc.c > @@ -608,31 +608,38 @@ static int iproc_pcie_config_write32(struct pci_bus *bus, unsigned int devfn, > .write = iproc_pcie_config_write32, > }; > > -static void iproc_pcie_reset(struct iproc_pcie *pcie) > +static void iproc_pcie_perst_ctrl(struct iproc_pcie *pcie, bool assert) > { > u32 val; > > /* > - * PAXC and the internal emulated endpoint device downstream should not > - * be reset. If firmware has been loaded on the endpoint device at an > - * earlier boot stage, reset here causes issues. > + * The internal emulated endpoints (such as PAXC) device downstream > + * should not be reset. If firmware has been loaded on the endpoint > + * device at an earlier boot stage, reset here causes issues. > */ > if (pcie->ep_is_internal) > return; > > - /* > - * Select perst_b signal as reset source. Put the device into reset, > - * and then bring it out of reset > - */ > - val = iproc_pcie_read_reg(pcie, IPROC_PCIE_CLK_CTRL); > - val &= ~EP_PERST_SOURCE_SELECT & ~EP_MODE_SURVIVE_PERST & > - ~RC_PCIE_RST_OUTPUT; > - iproc_pcie_write_reg(pcie, IPROC_PCIE_CLK_CTRL, val); > - udelay(250); > - > - val |= RC_PCIE_RST_OUTPUT; > - iproc_pcie_write_reg(pcie, IPROC_PCIE_CLK_CTRL, val); > - msleep(100); > + if (assert) { > + val = iproc_pcie_read_reg(pcie, IPROC_PCIE_CLK_CTRL); > + val &= ~EP_PERST_SOURCE_SELECT & ~EP_MODE_SURVIVE_PERST & > + ~RC_PCIE_RST_OUTPUT; > + iproc_pcie_write_reg(pcie, IPROC_PCIE_CLK_CTRL, val); > + udelay(250); > + } else { > + val = iproc_pcie_read_reg(pcie, IPROC_PCIE_CLK_CTRL); > + val |= RC_PCIE_RST_OUTPUT; > + iproc_pcie_write_reg(pcie, IPROC_PCIE_CLK_CTRL, val); > + msleep(100); > + } > +} > + > +int iproc_pcie_shutdown(struct iproc_pcie *pcie) > +{ > + iproc_pcie_perst_ctrl(pcie, true); > + msleep(500); > + > + return 0; > } Please export the symbol here to fix the build issue detected by kbuild test when the iProc PCIe platform driver is compiled as a kernel module. > > static int iproc_pcie_check_link(struct iproc_pcie *pcie, struct pci_bus *bus) > @@ -1310,7 +1317,8 @@ int iproc_pcie_setup(struct iproc_pcie *pcie, struct list_head *res) > goto err_exit_phy; > } > > - iproc_pcie_reset(pcie); > + iproc_pcie_perst_ctrl(pcie, true); > + iproc_pcie_perst_ctrl(pcie, false); > > if (pcie->need_ob_cfg) { > ret = iproc_pcie_map_ranges(pcie, res); > diff --git a/drivers/pci/host/pcie-iproc.h b/drivers/pci/host/pcie-iproc.h > index 0bbe2ea..a6b55ce 100644 > --- a/drivers/pci/host/pcie-iproc.h > +++ b/drivers/pci/host/pcie-iproc.h > @@ -110,6 +110,7 @@ struct iproc_pcie { > > int iproc_pcie_setup(struct iproc_pcie *pcie, struct list_head *res); > int iproc_pcie_remove(struct iproc_pcie *pcie); > +int iproc_pcie_shutdown(struct iproc_pcie *pcie); > > #ifdef CONFIG_PCIE_IPROC_MSI > int iproc_msi_init(struct iproc_pcie *pcie, struct device_node *node); >