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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B00D5C433F5 for ; Mon, 10 Jan 2022 09:10:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242269AbiAJJJ7 (ORCPT ); Mon, 10 Jan 2022 04:09:59 -0500 Received: from verein.lst.de ([213.95.11.211]:37684 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238722AbiAJJJ6 (ORCPT ); Mon, 10 Jan 2022 04:09:58 -0500 Received: by verein.lst.de (Postfix, from userid 2407) id 8A00968AA6; Mon, 10 Jan 2022 10:09:55 +0100 (CET) Date: Mon, 10 Jan 2022 10:09:55 +0100 From: Christoph Hellwig To: Florian Fainelli Cc: linux-mips@vger.kernel.org, =?utf-8?B?UmFmYcWCIE1pxYJlY2tp?= , Christoph Hellwig , Linus Walleij Subject: Re: [PATCH] bcma: get SoC device struct & assign dma_mask Message-ID: <20220110090955.GA7422@lst.de> References: <20220107041744.2388470-1-f.fainelli@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20220107041744.2388470-1-f.fainelli@gmail.com> User-Agent: Mutt/1.5.17 (2007-11-01) Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org On Thu, Jan 06, 2022 at 08:17:44PM -0800, Florian Fainelli wrote: > From: Rafał Miłecki > > For bus devices to be fully usable it's required to set their DMA > parameters. > > For years it has been missing and remained unnoticed because of > mips_dma_alloc_coherent() silently handling the empty coherent_dma_mask. > Kernel 4.19 came with a lot of DMA changes and caused a regression on > the bcm47xx. Starting with the commit f8c55dc6e828 ("MIPS: use generic > dma noncoherent ops for simple noncoherent platforms") DMA coherent > allocations just fail. Example: > [ 1.114914] bgmac_bcma bcma0:2: Allocation of TX ring 0x200 failed > [ 1.121215] bgmac_bcma bcma0:2: Unable to alloc memory for DMA > [ 1.127626] bgmac_bcma: probe of bcma0:2 failed with error -12 > [ 1.133838] bgmac_bcma: Broadcom 47xx GBit MAC driver loaded > > This change fixes above regression in addition to the MIPS bcm47xx > commit 321c46b91550 ("MIPS: BCM47XX: Setup struct device for the SoC"). How did it take so long to notice this? > I don't know if this is what you had in mind. I am also not sure if we > should have the bcma_bus_type implement .dma_configure and set it to > platform_dma_configure? Unless you have an OF tree that declares DMA limitations there is no need to call platform_dma_configure. > --- a/drivers/bcma/host_soc.c > +++ b/drivers/bcma/host_soc.c > @@ -191,6 +191,8 @@ int __init bcma_host_soc_init(struct bcma_soc *soc) > struct bcma_bus *bus = &soc->bus; > int err; > > + bus->dev = soc->dev; > + > /* Scan bus and initialize it */ > err = bcma_bus_early_register(bus); > if (err) > diff --git a/drivers/bcma/main.c b/drivers/bcma/main.c > index 8e7ca3e4c8c4..6793c2ff60fd 100644 > --- a/drivers/bcma/main.c > +++ b/drivers/bcma/main.c > @@ -253,6 +253,8 @@ void bcma_prepare_core(struct bcma_bus *bus, struct bcma_device *core) > if (IS_ENABLED(CONFIG_OF) && bus->dev) { > core->dma_dev = bus->dev; > } else { > + if (!core->dev.coherent_dma_mask) > + core->dev.coherent_dma_mask = DMA_BIT_MASK(32); Is there any way coherent_dma_mask could already be set here? > core->dev.dma_mask = &core->dev.coherent_dma_mask; > core->dma_dev = &core->dev; Not really needed for the quick fix, but pointing the dma_mask to the coherent_dma_mask is a bad idea as it removes the often used feature to use a different mask for the cohernent allocations vs the streaming mappings.