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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_PASS 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 20D36C282CB for ; Tue, 5 Feb 2019 11:22:54 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 42AFB2070B for ; Tue, 5 Feb 2019 11:22:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 42AFB2070B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 43v2Hb1fw7zDqDD for ; Tue, 5 Feb 2019 22:22:51 +1100 (AEDT) Received: from ozlabs.org (bilbo.ozlabs.org [IPv6:2401:3900:2:1::2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 43v2F371z5zDqCq for ; Tue, 5 Feb 2019 22:20:39 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPSA id 43v2F35Mfjz9sMp; Tue, 5 Feb 2019 22:20:39 +1100 (AEDT) From: Michael Ellerman To: Christoph Hellwig Subject: Re: [RFC PATCH] powerpc: fix get_arch_dma_ops() for NTB devices In-Reply-To: <20190204081752.GA5730@lst.de> References: <20190128133203.mon4a3nkrzijn43g@alfbook-pro.local> <87imy6pain.fsf@concordia.ellerman.id.au> <20190204081752.GA5730@lst.de> Date: Tue, 05 Feb 2019 22:20:32 +1100 Message-ID: <87h8dimqgv.fsf@concordia.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linuxppc-dev@lists.ozlabs.org, Christoph Hellwig , Alexander Fomichev , linux@yadro.com Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Christoph Hellwig writes: > On Wed, Jan 30, 2019 at 11:58:40PM +1100, Michael Ellerman wrote: >> Alexander Fomichev writes: >> >> > get_dma_ops() falls into arch-dependant get_arch_dma_ops(), which >> > historically returns NULL on PowerPC. Therefore dma_set_mask() fails. >> > This affects Switchtec (and probably other) NTB devices, that they fail >> > to initialize. >> >> What's an NTB device? >> >> drivers/ntb I assume? >> >> So it's a PCI device of some sort, but presumably the device you're >> calling dma_set_mask() on is an NTB device not a PCI device? >> >> But then it works if you tell it to use the PCI DMA ops? >> >> At the very least the code should be checking for the NTB bus type and >> only returning the PCI ops in that specific case, not for all devices. > > Can you provide the context? E.g. the patch and the rest of the commit > log. This all looks rather odd to me. Sorry, here it is. Or on lore: https://lore.kernel.org/linuxppc-dev/20190128133203.mon4a3nkrzijn43g@alfbook-pro.local/ Subject: [RFC PATCH] powerpc: fix get_arch_dma_ops() for NTB devices get_dma_ops() falls into arch-dependant get_arch_dma_ops(), which historically returns NULL on PowerPC. Therefore dma_set_mask() fails. This affects Switchtec (and probably other) NTB devices, that they fail to initialize. The proposed patch should fix the issue. --- arch/powerpc/include/asm/dma-mapping.h | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) diff --git a/arch/powerpc/include/asm/dma-mapping.h b/arch/powerpc/include/asm/dma-mapping.h index ebf6680..cb6ac96 100644 --- a/arch/powerpc/include/asm/dma-mapping.h +++ b/arch/powerpc/include/asm/dma-mapping.h @@ -70,14 +70,11 @@ extern struct dma_map_ops dma_iommu_ops; #endif extern const struct dma_map_ops dma_nommu_ops; +extern const struct dma_map_ops *get_pci_dma_ops(void); + static inline const struct dma_map_ops *get_arch_dma_ops(struct bus_type *bus) { - /* We don't handle the NULL dev case for ISA for now. We could - * do it via an out of line call but it is not needed for now. The - * only ISA DMA device we support is the floppy and we have a hack - * in the floppy driver directly to get a device for us. - */ - return NULL; + return get_pci_dma_ops(); } /*