From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751453AbeECIii (ORCPT ); Thu, 3 May 2018 04:38:38 -0400 Received: from kvm5.telegraphics.com.au ([98.124.60.144]:56614 "EHLO kvm5.telegraphics.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751196AbeECIif (ORCPT ); Thu, 3 May 2018 04:38:35 -0400 Date: Thu, 3 May 2018 18:38:21 +1000 (AEST) From: Finn Thain To: Geert Uytterhoeven cc: "David S. Miller" , linux-m68k@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH net] macmace: Set platform device coherent_dma_mask In-Reply-To: Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 3 May 2018, Geert Uytterhoeven wrote: > > --- a/drivers/net/ethernet/apple/macmace.c > > +++ b/drivers/net/ethernet/apple/macmace.c > > @@ -203,6 +203,10 @@ static int mace_probe(struct platform_device *pdev) > > unsigned char checksum = 0; > > int err; > > > > + err = dma_coerce_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32)); > > + if (err) > > + return err; > > + > > dev = alloc_etherdev(PRIV_BYTES); > > if (!dev) > > return -ENOMEM; > > Shouldn't this be handled in the platform code that instantiates the > device, i.e. in arch/m68k/mac/config.c:mac_platform_init()? > I wondered about that too. The downside is that I'd have to convert platform_device_register_simple() into platform_device_register() and add all of the boilerplate that goes with that, for little gain. > Cfr. commit f61e64310b75733d ("m68k: set dma and coherent masks for > platform FEC ethernets"). > Yes, I looked at that patch before I sent this one. It makes sense to set the mask when defining the device since some devices tend to have inherent limitations (but that's not really applicable here). Moreover, it turns out that a number of platform drivers already call dma_set_mask_and_coherent() or dma_coerce_mask_and_coherent() or similar. I figured that platform drivers aren't expected to be particularly portable. Well, I'd expect macmace and macsonic to be portable to NuBus PowerMacs, but AFAIK the correct mask would remain DMA_BIT_MASK(32). So that's how I ended up with this patch. But if you are not pursuaded by my reasoning then just say the word and I'll take another approach. -- > Gr{oetje,eeting}s, > > Geert > From mboxrd@z Thu Jan 1 00:00:00 1970 From: Finn Thain Subject: Re: [PATCH net] macmace: Set platform device coherent_dma_mask Date: Thu, 3 May 2018 18:38:21 +1000 (AEST) Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Cc: "David S. Miller" , linux-m68k@lists.linux-m68k.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: Geert Uytterhoeven Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Thu, 3 May 2018, Geert Uytterhoeven wrote: > > --- a/drivers/net/ethernet/apple/macmace.c > > +++ b/drivers/net/ethernet/apple/macmace.c > > @@ -203,6 +203,10 @@ static int mace_probe(struct platform_device *pdev) > > unsigned char checksum = 0; > > int err; > > > > + err = dma_coerce_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32)); > > + if (err) > > + return err; > > + > > dev = alloc_etherdev(PRIV_BYTES); > > if (!dev) > > return -ENOMEM; > > Shouldn't this be handled in the platform code that instantiates the > device, i.e. in arch/m68k/mac/config.c:mac_platform_init()? > I wondered about that too. The downside is that I'd have to convert platform_device_register_simple() into platform_device_register() and add all of the boilerplate that goes with that, for little gain. > Cfr. commit f61e64310b75733d ("m68k: set dma and coherent masks for > platform FEC ethernets"). > Yes, I looked at that patch before I sent this one. It makes sense to set the mask when defining the device since some devices tend to have inherent limitations (but that's not really applicable here). Moreover, it turns out that a number of platform drivers already call dma_set_mask_and_coherent() or dma_coerce_mask_and_coherent() or similar. I figured that platform drivers aren't expected to be particularly portable. Well, I'd expect macmace and macsonic to be portable to NuBus PowerMacs, but AFAIK the correct mask would remain DMA_BIT_MASK(32). So that's how I ended up with this patch. But if you are not pursuaded by my reasoning then just say the word and I'll take another approach. -- > Gr{oetje,eeting}s, > > Geert >