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=-16.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 0BFF1C432BE for ; Tue, 10 Aug 2021 22:32:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DB5DA60EBD for ; Tue, 10 Aug 2021 22:32:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235107AbhHJWdL (ORCPT ); Tue, 10 Aug 2021 18:33:11 -0400 Received: from mail.kernel.org ([198.145.29.99]:42246 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231380AbhHJWdK (ORCPT ); Tue, 10 Aug 2021 18:33:10 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2FD2960F94; Tue, 10 Aug 2021 22:32:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1628634767; bh=jBhUSswXbu7eqOIoOTNA6LTai3QKt3yxiCxd0AsaSVM=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=UlmwruyWNcVqCzdrGmJPwoT3zO+oq3c4bN4e1EG0j8Ii782GwufWkNoeuTDL0xflB ibTEtBFLr0igVxyV7HL8hPn+SCaP1x3th5gqtBsam28jRK9tdNeL2wovy8u/qrpKWL +3ON1m8q99OGqedxcga0dnuz8NVYmecq+yg2bUs024Ngg71HgXSIe9W4JRi++hh349 SIt0uQxYWMXOgIAKY+5YfI8XqoxtksF9hr0fyuWl6G698LuWhGbGg24ZrDtltwIF1q ryYvHMuiPy/tBFJDq/n+5m6kmjByrUKxp9FT2Oz6rL/iywuYUqYIv5Nhwdvs3r7oD4 GosihRIA4TfYw== Date: Tue, 10 Aug 2021 17:32:45 -0500 From: Bjorn Helgaas To: Sergio Paracuellos Cc: tsbogend@alpha.franken.de, bhelgaas@google.com, matthias.bgg@gmail.com, gregkh@linuxfoundation.org, linux-mips@vger.kernel.org, linux-pci@vger.kernel.org, linux-staging@lists.linux.dev, neil@brown.name, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/3] PCI: of: avoid 'devm_pci_remap_iospace' if PCI_IOBASE is not defined Message-ID: <20210810223245.GA2311409@bjorn-Precision-5520> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210807072409.9018-3-sergio.paracuellos@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Aug 07, 2021 at 09:24:08AM +0200, Sergio Paracuellos wrote: > Defining PCI_IOBASE for MIPS ralink in expected addresses results in PCI IO > resources being assigned but the addresses generated for IO accesses are wrong > since the ioremap in the PCI core function 'pci_parse_request_of_pci_ranges' > tries to remap to a fixed virtual address (PC_IOBASE) which can't work for KSEG1 > addresses. To get it working this way, we would need to put PCI_IOBASE somewhere > into KSEG2 which will result in creating TLB entries for IO addresses, which most > of the time isn't needed on MIPS because of access via KSEG1. To allow MIPS PCI > drivers to properly use the PCI generic core we need to increase IO_SPACE_LIMIT > since IO addresses are in addresses higher that 0xffff. We also need to avoid > the call 'devm_pci_remap_iospace' when 'pci_parse_request_of_pci_ranges' is > called to avoid the following problem: Rewrap to fit in ~75 columns. This is a generic change so the commit log needs to be generic as well. The MIPS/KSEG1/KSEG2 information is not really useful here because most readers won't understand it (and I don't :)). devm_pci_remap_iospace() calls pci_remap_iospace(), which already contains #ifdef PCI_IOBASE. When PCI_IOBASE is not defined (as on MIPS ralink), it emits the warning below and returns failure. This patch avoids that failure, but it still leaves devm_pci_remap_iospace() and pci_remap_iospace() broken on MIPS ralink. It's true that on MIPS ralink, they are currently only called via pci_parse_request_of_pci_ranges(), but I think it would be better if we could fix pci_remap_iospace() to handle this case so all these interfaces work consistently. This patch doesn't do anything with IO_SPACE_LIMIT, so I don't know what that part of the commit log is telling me. > ------------[ cut here ]------------ > WARNING: CPU: 2 PID: 1 at ../drivers/pci/pci.c:4066 pci_remap_iospace+0x3c/0x54 > This architecture does not support memory mapped I/O > Modules linked in: > CPU: 2 PID: 1 Comm: swapper/0 Not tainted 5.10.1+ #1228 > Stack : 00000000 00000000 807fa974 00000000 827ffa80 80066b48 80710000 0000000b > 00000000 00000000 81c59aac 7d06ddec 80850000 00000001 81c59a40 7d06ddec > 00000000 00000000 807c909c 81c598f0 00000001 81c59904 00000000 0000000a > 203a6d6d 80708880 0000000f 70617773 80850000 00000000 00000000 807d0000 > 807ffecc 1e160000 00000001 00000200 00000000 8054e920 00000008 815e0008 > ... > Call Trace: > [<80008efc>] show_stack+0x8c/0x130 > [<806e1674>] dump_stack+0x9c/0xc8 > [<80024a3c>] __warn+0xc0/0xe8 > [<80024ad0>] warn_slowpath_fmt+0x6c/0xbc > [<80410ca8>] pci_remap_iospace+0x3c/0x54 > [<80410d20>] devm_pci_remap_iospace+0x58/0xa4 > [<8042019c>] devm_of_pci_bridge_init+0x4dc/0x55c > [<80408de8>] devm_pci_alloc_host_bridge+0x78/0x88 > [<80424e44>] mt7621_pci_probe+0x68/0x9a4 > [<80464804>] platform_drv_probe+0x40/0x7c > [<804628bc>] really_probe+0x2fc/0x4e4 > [<80463214>] device_driver_attach+0x4c/0x74 > [<80463384>] __driver_attach+0x148/0x150 > [<8046047c>] bus_for_each_dev+0x6c/0xb0 > [<804614dc>] bus_add_driver+0x1b4/0x1fc > [<80463aa0>] driver_register+0xd0/0x110 > [<80001714>] do_one_initcall+0x84/0x1c0 > [<808e7fd0>] kernel_init_freeable+0x214/0x24c > [<806e4164>] kernel_init+0x14/0x118 > [<80003358>] ret_from_kernel_thread+0x14/0x1c > > ---[ end trace 1c9d4412bd51b53c ]--- > mt7621-pci 1e140000.pcie: error -19: failed to map resource [io 0x1e160000-0x1e16ffff] > > Hence don't call 'devm_pci_remap_iospace' if PCI_IOBASE is not defined to get > a working PCI core APIs for MIPS ralink platforms. > > Signed-off-by: Sergio Paracuellos > --- > drivers/pci/of.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/pci/of.c b/drivers/pci/of.c > index a143b02b2dcd..657aef39bf63 100644 > --- a/drivers/pci/of.c > +++ b/drivers/pci/of.c > @@ -564,12 +564,14 @@ static int pci_parse_request_of_pci_ranges(struct device *dev, > > switch (resource_type(res)) { > case IORESOURCE_IO: > +#ifdef PCI_IOBASE > err = devm_pci_remap_iospace(dev, res, iobase); > if (err) { > dev_warn(dev, "error %d: failed to map resource %pR\n", > err, res); > resource_list_destroy_entry(win); > } > +#endif > break; > case IORESOURCE_MEM: > res_valid |= !(res->flags & IORESOURCE_PREFETCH); > -- > 2.25.1 >