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 D9C2DC433EF for ; Tue, 22 Feb 2022 21:30:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231492AbiBVVbD (ORCPT ); Tue, 22 Feb 2022 16:31:03 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58962 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230181AbiBVVbC (ORCPT ); Tue, 22 Feb 2022 16:31:02 -0500 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 6914A12A748; Tue, 22 Feb 2022 13:30:36 -0800 (PST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 27135139F; Tue, 22 Feb 2022 13:30:36 -0800 (PST) Received: from [10.57.40.147] (unknown [10.57.40.147]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 37F8E3F70D; Tue, 22 Feb 2022 13:30:34 -0800 (PST) Message-ID: Date: Tue, 22 Feb 2022 21:30:30 +0000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:91.0) Gecko/20100101 Thunderbird/91.6.1 Subject: Re: [PATCH v3 2/9] gpu: host1x: Add context bus Content-Language: en-GB To: Christoph Hellwig , Mikko Perttunen Cc: thierry.reding@gmail.com, jonathanh@nvidia.com, joro@8bytes.org, will@kernel.org, robh+dt@kernel.org, linux-tegra@vger.kernel.org, dri-devel@lists.freedesktop.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org References: <20220218113952.3077606-1-mperttunen@nvidia.com> <20220218113952.3077606-3-mperttunen@nvidia.com> From: Robin Murphy In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-tegra@vger.kernel.org On 2022-02-22 16:21, Christoph Hellwig wrote: > On Fri, Feb 18, 2022 at 01:39:45PM +0200, Mikko Perttunen wrote: >> The context bus is a "dummy" bus that contains struct devices that >> correspond to IOMMU contexts assigned through Host1x to processes. >> >> Even when host1x itself is built as a module, the bus is registered >> in built-in code so that the built-in ARM SMMU driver is able to >> reference it. >> >> Signed-off-by: Mikko Perttunen >> --- >> drivers/gpu/Makefile | 3 +-- >> drivers/gpu/host1x/Kconfig | 5 +++++ >> drivers/gpu/host1x/Makefile | 1 + >> drivers/gpu/host1x/context_bus.c | 31 ++++++++++++++++++++++++++++++ >> include/linux/host1x_context_bus.h | 15 +++++++++++++++ >> 5 files changed, 53 insertions(+), 2 deletions(-) >> create mode 100644 drivers/gpu/host1x/context_bus.c >> create mode 100644 include/linux/host1x_context_bus.h >> >> diff --git a/drivers/gpu/Makefile b/drivers/gpu/Makefile >> index 835c88318cec..8997f0096545 100644 >> --- a/drivers/gpu/Makefile >> +++ b/drivers/gpu/Makefile >> @@ -2,7 +2,6 @@ >> # drm/tegra depends on host1x, so if both drivers are built-in care must be >> # taken to initialize them in the correct order. Link order is the only way >> # to ensure this currently. >> -obj-$(CONFIG_TEGRA_HOST1X) += host1x/ >> -obj-y += drm/ vga/ >> +obj-y += host1x/ drm/ vga/ >> obj-$(CONFIG_IMX_IPUV3_CORE) += ipu-v3/ >> obj-$(CONFIG_TRACE_GPU_MEM) += trace/ >> diff --git a/drivers/gpu/host1x/Kconfig b/drivers/gpu/host1x/Kconfig >> index 6815b4db17c1..1861a8180d3f 100644 >> --- a/drivers/gpu/host1x/Kconfig >> +++ b/drivers/gpu/host1x/Kconfig >> @@ -1,8 +1,13 @@ >> # SPDX-License-Identifier: GPL-2.0-only >> + >> +config TEGRA_HOST1X_CONTEXT_BUS >> + bool >> + >> config TEGRA_HOST1X >> tristate "NVIDIA Tegra host1x driver" >> depends on ARCH_TEGRA || (ARM && COMPILE_TEST) >> select DMA_SHARED_BUFFER >> + select TEGRA_HOST1X_CONTEXT_BUS >> select IOMMU_IOVA >> help >> Driver for the NVIDIA Tegra host1x hardware. >> diff --git a/drivers/gpu/host1x/Makefile b/drivers/gpu/host1x/Makefile >> index d2b6f7de0498..c891a3e33844 100644 >> --- a/drivers/gpu/host1x/Makefile >> +++ b/drivers/gpu/host1x/Makefile >> @@ -18,3 +18,4 @@ host1x-y = \ >> hw/host1x07.o >> >> obj-$(CONFIG_TEGRA_HOST1X) += host1x.o >> +obj-$(CONFIG_TEGRA_HOST1X_CONTEXT_BUS) += context_bus.o >> diff --git a/drivers/gpu/host1x/context_bus.c b/drivers/gpu/host1x/context_bus.c >> new file mode 100644 >> index 000000000000..2625914f3c7d >> --- /dev/null >> +++ b/drivers/gpu/host1x/context_bus.c >> @@ -0,0 +1,31 @@ >> +// SPDX-License-Identifier: GPL-2.0-only >> +/* >> + * Copyright (c) 2021, NVIDIA Corporation. >> + */ >> + >> +#include >> +#include >> + >> +struct bus_type host1x_context_device_bus_type = { >> + .name = "host1x-context", >> +}; >> +EXPORT_SYMBOL(host1x_context_device_bus_type); > > EXPORT_SYMBOL_GPL, please. > > But the pattern that this copies in arm_smmu_bus_init is really > ugly. I think we need to figure out a way todo that without having > to export all the low-level bus types. Yup, as it happens that was the first step on my mission :) https://gitlab.arm.com/linux-arm/linux-rm/-/commits/iommu/bus Still a way to go with the main meat of that work, though, so I was figuring this could probably land as-is and I'll sweep it up in due course. Robin.