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 F3693C6FD20 for ; Fri, 24 Mar 2023 13:24:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231699AbjCXNY4 (ORCPT ); Fri, 24 Mar 2023 09:24:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49524 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232064AbjCXNYx (ORCPT ); Fri, 24 Mar 2023 09:24:53 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id EB798EB4D for ; Fri, 24 Mar 2023 06:24:51 -0700 (PDT) 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 B5A6111FB; Fri, 24 Mar 2023 06:25:35 -0700 (PDT) Received: from [10.1.28.32] (e122027.cambridge.arm.com [10.1.28.32]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 742EC3F766; Fri, 24 Mar 2023 06:24:49 -0700 (PDT) Message-ID: <859ef16c-bf31-78f2-f3df-cf0ff9493b3c@arm.com> Date: Fri, 24 Mar 2023 13:24:47 +0000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.8.0 Subject: Re: [PATCH v2] iommu/rockchip: Add missing set_platform_dma_ops callback Content-Language: en-GB To: Baolu Lu , Heiko Stuebner , Joerg Roedel , Jason Gunthorpe Cc: Will Deacon , Robin Murphy , iommu@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-rockchip@lists.infradead.org References: <20230324111127.221640-1-steven.price@arm.com> <8fda817c-98e7-1988-325d-52d09f3e61a8@linux.intel.com> From: Steven Price In-Reply-To: <8fda817c-98e7-1988-325d-52d09f3e61a8@linux.intel.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 24/03/2023 13:16, Baolu Lu wrote: > On 2023/3/24 19:11, Steven Price wrote: >> Similar to exynos, we need a set_platform_dma_ops() callback for proper >> operation on ARM 32 bit after recent changes in the IOMMU framework >> (detach ops removal). But also the use of a NULL domain is confusing. >> >> Rework the code to have a singleton rk_identity_domain which is assigned >> to domain when using an identity mapping rather than "detaching". This >> makes the code easier to reason about. >> >> Signed-off-by: Steven Price >> --- >> Changes since v1[1]: >> >>   * Reworked the code to avoid a NULL domain, instead a singleton >>     rk_identity_domain is used instead. The 'detach' language is no >>     longer used. >> >> [1] >> https://lore.kernel.org/r/20230315164152.333251-1-steven.price%40arm.com >> >>   drivers/iommu/rockchip-iommu.c | 50 ++++++++++++++++++++++++++-------- >>   1 file changed, 39 insertions(+), 11 deletions(-) >> >> diff --git a/drivers/iommu/rockchip-iommu.c >> b/drivers/iommu/rockchip-iommu.c >> index f30db22ea5d7..437541004994 100644 >> --- a/drivers/iommu/rockchip-iommu.c >> +++ b/drivers/iommu/rockchip-iommu.c >> @@ -124,6 +124,7 @@ struct rk_iommudata { >>     static struct device *dma_dev; >>   static const struct rk_iommu_ops *rk_ops; >> +static struct iommu_domain rk_identity_domain; >>     static inline void rk_table_flush(struct rk_iommu_domain *dom, >> dma_addr_t dma, >>                     unsigned int count) >> @@ -980,26 +981,27 @@ static int rk_iommu_enable(struct rk_iommu *iommu) >>       return ret; >>   } >>   -static void rk_iommu_detach_device(struct iommu_domain *domain, >> -                   struct device *dev) >> +static int rk_iommu_identity_attach(struct iommu_domain >> *identity_domain, >> +                    struct device *dev) >>   { >>       struct rk_iommu *iommu; >> -    struct rk_iommu_domain *rk_domain = to_rk_domain(domain); >> +    struct rk_iommu_domain *rk_domain; >>       unsigned long flags; >>       int ret; >>         /* Allow 'virtual devices' (eg drm) to detach from domain */ >>       iommu = rk_iommu_from_dev(dev); >>       if (!iommu) >> -        return; >> +        return -ENODEV; >> + >> +    rk_domain = to_rk_domain(iommu->domain); >>         dev_dbg(dev, "Detaching from iommu domain\n"); >>   -    /* iommu already detached */ >> -    if (iommu->domain != domain) >> -        return; >> +    if (iommu->domain == identity_domain) >> +        return 0; >>   -    iommu->domain = NULL; >> +    iommu->domain = identity_domain; > > Where did identity_domain come from? Is it rk_identity_domain? It's a parameter of the function. In the case of the call in rk_iommu_attach_device() then, yes, it's rk_identity_domain. But this function is also the "attach_dev" callback of "rk_identity_ops". I'll admit this is cargo-culted from Jason's example: https://lore.kernel.org/linux-iommu/ZBnef7g7GCxogPNz@ziepe.ca/ Steve > Best regards, > baolu