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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 81D03C43331 for ; Fri, 6 Sep 2019 10:01:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5EB872084F for ; Fri, 6 Sep 2019 10:01:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729405AbfIFKBR (ORCPT ); Fri, 6 Sep 2019 06:01:17 -0400 Received: from foss.arm.com ([217.140.110.172]:53846 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732160AbfIFKBR (ORCPT ); Fri, 6 Sep 2019 06:01:17 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B67721570; Fri, 6 Sep 2019 03:01:16 -0700 (PDT) Received: from localhost (unknown [10.37.6.20]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 2F8F23F59C; Fri, 6 Sep 2019 03:01:16 -0700 (PDT) Date: Fri, 6 Sep 2019 11:01:14 +0100 From: Andrew Murray To: Abhishek Shah Cc: Lorenzo Pieralisi , Bjorn Helgaas , Ray Jui , Scott Branden , linux-pci@vger.kernel.org, linux-arm-kernel , open list , BCM Kernel Feedback Subject: Re: [PATCH 1/1] PCI: iproc: Invalidate PAXB address mapping before programming it Message-ID: <20190906100114.GE9720@e119886-lin.cambridge.arm.com> References: <20190906035813.24046-1-abhishek.shah@broadcom.com> <20190906083816.GD9720@e119886-lin.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1+81 (426a6c1) (2018-08-26) Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Fri, Sep 06, 2019 at 02:55:19PM +0530, Abhishek Shah wrote: > Hi Andrew, > > Thanks for the review. Please see my response inline: > > On Fri, Sep 6, 2019 at 2:08 PM Andrew Murray wrote: > > > > On Fri, Sep 06, 2019 at 09:28:13AM +0530, Abhishek Shah wrote: > > > Invalidate PAXB inbound/outbound address mapping each time before > > > programming it. This is helpful for the cases where we need to > > > reprogram inbound/outbound address mapping without resetting PAXB. > > > kexec kernel is one such example. > > > > Why is this approach better than resetting the PAXB (I assume that's > > the PCI controller IP)? Wouldn't resetting the PAXB address this issue, > > and ensure that no other configuration is left behind? > > > We normally reset PAXB in the firmware(ATF). But for cases like kexec > kernel boot, > we do not execute any firmware code and directly boot into kernel. > > We could have done PAXB reset in the driver itself as you have suggested here. > But note that this detail could vary for each SoC, because these > registers are not part > of PAXB register space itself, rather exists in a register space responsible for > controlling power to various wrappers in PCIe IP. Normally, this kind > of SoC specific > details are handled in firmware itself, we don't bring them to driver level. OK understood. > > > Or is this related to earlier boot stages loading firmware for the emulated > > downstream endpoints (ep_is_internal)? > > > > Finally, in the case where ep_is_internal do you need to disable anything > > prior to invalidating the mappings? > > > No, ep_is_internal is indicator for PAXC IP. It does not have > mappings as in PAXB. I think I meant !ep_is_internal. I.e. is there possibility of inbound traffic prior to invalidating the mappings. I'd assume not, but that's an assumption. Either way: Reviewed-by: Andrew Murray > > > Regards, > Abhishek > > > > > > Signed-off-by: Abhishek Shah > > > Reviewed-by: Ray Jui > > > Reviewed-by: Vikram Mysore Prakash > > > --- > > > drivers/pci/controller/pcie-iproc.c | 28 ++++++++++++++++++++++++++++ > > > 1 file changed, 28 insertions(+) > > > > > > diff --git a/drivers/pci/controller/pcie-iproc.c b/drivers/pci/controller/pcie-iproc.c > > > index e3ca46497470..99a9521ba7ab 100644 > > > --- a/drivers/pci/controller/pcie-iproc.c > > > +++ b/drivers/pci/controller/pcie-iproc.c > > > @@ -1245,6 +1245,32 @@ static int iproc_pcie_map_dma_ranges(struct iproc_pcie *pcie) > > > return ret; > > > } > > > > > > +static void iproc_pcie_invalidate_mapping(struct iproc_pcie *pcie) > > > +{ > > > + struct iproc_pcie_ib *ib = &pcie->ib; > > > + struct iproc_pcie_ob *ob = &pcie->ob; > > > + int idx; > > > + > > > + if (pcie->ep_is_internal) > > > + return; > > > + > > > + if (pcie->need_ob_cfg) { > > > + /* iterate through all OARR mapping regions */ > > > + for (idx = ob->nr_windows - 1; idx >= 0; idx--) { > > > + iproc_pcie_write_reg(pcie, > > > + MAP_REG(IPROC_PCIE_OARR0, idx), 0); > > > + } > > > + } > > > + > > > + if (pcie->need_ib_cfg) { > > > + /* iterate through all IARR mapping regions */ > > > + for (idx = 0; idx < ib->nr_regions; idx++) { > > > + iproc_pcie_write_reg(pcie, > > > + MAP_REG(IPROC_PCIE_IARR0, idx), 0); > > > + } > > > + } > > > +} > > > + > > > static int iproce_pcie_get_msi(struct iproc_pcie *pcie, > > > struct device_node *msi_node, > > > u64 *msi_addr) > > > @@ -1517,6 +1543,8 @@ int iproc_pcie_setup(struct iproc_pcie *pcie, struct list_head *res) > > > iproc_pcie_perst_ctrl(pcie, true); > > > iproc_pcie_perst_ctrl(pcie, false); > > > > > > + iproc_pcie_invalidate_mapping(pcie); > > > + > > > if (pcie->need_ob_cfg) { > > > ret = iproc_pcie_map_ranges(pcie, res); > > > if (ret) { > > > > The code changes look good to me. > > > > Thanks, > > > > Andrew Murray > > > > > -- > > > 2.17.1 > > >