Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753581AbdF0UkZ (ORCPT ); Tue, 27 Jun 2017 16:40:25 -0400 Received: from mail-io0-f193.google.com ([209.85.223.193]:36131 "EHLO mail-io0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753475AbdF0UkS (ORCPT ); Tue, 27 Jun 2017 16:40:18 -0400 MIME-Version: 1.0 In-Reply-To: <3ffb5648-00f6-26cb-116a-370085038a0d@deltatee.com> References: <20170622164817.25515-1-logang@deltatee.com> <20170622164817.25515-7-logang@deltatee.com> <504da99a-838c-48ec-c5b2-6b611d587a10@ti.com> <3ffb5648-00f6-26cb-116a-370085038a0d@deltatee.com> From: Arnd Bergmann Date: Tue, 27 Jun 2017 22:40:16 +0200 X-Google-Sender-Auth: qS0_gmhTnDRwdsoLHEzajrp_114 Message-ID: Subject: Re: [PATCH 6/7] drm/tilcdc: clean up ifdef hacks around iowrite64 To: Logan Gunthorpe Cc: Jyri Sarha , Linux Kernel Mailing List , linux-arch , linux-ntb@googlegroups.com, linux-alpha@vger.kernel.org, linuxppc-dev , linux-crypto@vger.kernel.org, dri-devel , Greg Kroah-Hartman , Stephen Bates , Tomi Valkeinen , David Airlie Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1034 Lines: 24 On Mon, Jun 26, 2017 at 6:26 PM, Logan Gunthorpe wrote: > Hi Jyri, > > Thanks for the ack. However, I'm reworking this patch set to use the > include/linux/io-64-nonatomic* headers which will explicitly devolve > into two 32-bit transfers. It's not clear whether this is appropriate > for the tilcdc driver as it was never setup to use 32-bit transfers > (unlike the others I had patched). > > If you think it's ok, I can still patch this driver to use the > non-atomic headers. Otherwise I can leave it out. Please let me know. You'd have to first figure out whether this device is of the lo-hi or the hi-lo variant, or doesn't allow the I/O to be split at all. Note that we could theoretically define ARM to use strd/ldrd for writeq/readq, but I would expect that to be wrong with many other devices that can use the existing io-64-nonatomic headers. The comment in set_scanout() suggests that we actually do rely on the write64 to be atomic, so we probably don't want to change this driver. Arnd