From patchwork Tue Nov 8 17:06:19 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Robin Murphy X-Patchwork-Id: 13036562 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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A633CC433FE for ; Tue, 8 Nov 2022 17:06:34 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id F1C2710E4C7; Tue, 8 Nov 2022 17:06:32 +0000 (UTC) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by gabe.freedesktop.org (Postfix) with ESMTP id AB6DD10E4C7 for ; Tue, 8 Nov 2022 17:06:28 +0000 (UTC) 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 239B01FB; Tue, 8 Nov 2022 09:06:34 -0800 (PST) Received: from e121345-lin.cambridge.arm.com (e121345-lin.cambridge.arm.com [10.1.196.40]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id F308E3F703; Tue, 8 Nov 2022 09:06:26 -0800 (PST) From: Robin Murphy To: robh@kernel.org, tomeu.vizoso@collabora.com, steven.price@arm.com Subject: [PATCH] drm/panfrost: Split io-pgtable requests properly Date: Tue, 8 Nov 2022 17:06:19 +0000 Message-Id: <49e54bb4019cd06e01549b106d7ac37c3d182cd3.1667927179.git.robin.murphy@arm.com> X-Mailer: git-send-email 2.36.1.dirty MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-arm-kernel@lists.infradead.org, Dmitry Osipenko , alyssa.rosenzweig@collabora.com, dri-devel@lists.freedesktop.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Although we don't use 1GB block mappings, we still need to split map/unmap requests at 1GB boundaries to match what io-pgtable expects. Fix that, and add some explanation to make sense of it all. Fixes: 3740b081795a ("drm/panfrost: Update io-pgtable API") Reported-by: Dmitry Osipenko Signed-off-by: Robin Murphy Tested-by: Dmitry Osipenko Reviewed-by: Steven Price --- The previous diff turned out to be not quite right, so I've not included Dmitry's Tested-by given for that. --- drivers/gpu/drm/panfrost/panfrost_mmu.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/panfrost/panfrost_mmu.c b/drivers/gpu/drm/panfrost/panfrost_mmu.c index e246d914e7f6..4e83a1891f3e 100644 --- a/drivers/gpu/drm/panfrost/panfrost_mmu.c +++ b/drivers/gpu/drm/panfrost/panfrost_mmu.c @@ -250,13 +250,22 @@ void panfrost_mmu_reset(struct panfrost_device *pfdev) static size_t get_pgsize(u64 addr, size_t size, size_t *count) { + /* + * io-pgtable only operates on multiple pages within a single table + * entry, so we need to split at boundaries of the table size, i.e. + * the next block size up. The distance from address A to the next + * boundary of block size B is logically B - A % B, but in unsigned + * two's complement where B is a power of two we get the equivalence + * B - A % B == (B - A) % B == (n * B - A) % B, and choose n = 0 :) + */ size_t blk_offset = -addr % SZ_2M; if (blk_offset || size < SZ_2M) { *count = min_not_zero(blk_offset, size) / SZ_4K; return SZ_4K; } - *count = size / SZ_2M; + blk_offset = -addr % SZ_1G ?: SZ_1G; + *count = min(blk_offset, size) / SZ_2M; return SZ_2M; }