From patchwork Mon Mar 7 15:56:53 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: AngeloGioacchino Del Regno X-Patchwork-Id: 12772059 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 2ED94C43217 for ; Mon, 7 Mar 2022 15:57:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242788AbiCGP6B (ORCPT ); Mon, 7 Mar 2022 10:58:01 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49354 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243986AbiCGP56 (ORCPT ); Mon, 7 Mar 2022 10:57:58 -0500 Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [46.235.227.227]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0A5CB7D00F; Mon, 7 Mar 2022 07:57:03 -0800 (PST) Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: kholk11) with ESMTPSA id D3E731F43DE9 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1646668622; bh=6NoOklKLAvSst15nOrzs5E10D4lpohNoFGlreOLuXl0=; h=From:To:Cc:Subject:Date:From; b=RHBjRupZj0c8esNwufh5vf3czfEKDc/TX4C2+dN2UNabI1D3e+C0xSAlDfwnpiYK8 Mg0lSXIa/yrlNUpzy2xYENcDpQ3IxknhWVICVnNncb/oSBDScemMddZteuM3+Grf2p Xea/DVARxjmj2MccLrD/zYUdCB7j5J4dpkuMsLoHiRTekU8JxIX86Nwct1OStnLxPC wtp6/Cd+/ymSmTmY5YNr8+VgPO2Kx9Zwbd3EVX7Zj2RPODGhiH4NYiTNS0xG0lC5O1 CACHM5APJKHsBlf8TVPMjCtsx3oMmDTwsLfNbQZbvm0RJlaOOijBU9xerFFff2m5RN 7mUIAw5bvHyqg== From: AngeloGioacchino Del Regno To: minghsiu.tsai@mediatek.com Cc: houlong.wei@mediatek.com, andrew-ct.chen@mediatek.com, mchehab@kernel.org, matthias.bgg@gmail.com, hans.verkuil@cisco.com, linux-media@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org, kernel@collabora.com, acourbot@chromium.org, irui.wang@mediatek.com, AngeloGioacchino Del Regno Subject: [PATCH] media: platform: mtk-mdp: Fix mdp_ipi_comm structure alignment Date: Mon, 7 Mar 2022 16:56:53 +0100 Message-Id: <20220307155653.460910-1-angelogioacchino.delregno@collabora.com> X-Mailer: git-send-email 2.35.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org The mdp_ipi_comm structure defines a command that is either PROCESS (start processing) or DEINIT (destroy instance); we are using this one to send PROCESS or DEINIT commands from Linux to an MDP instance through a VPU write but, while the first wants us to stay 4-bytes aligned, the VPU instead requires an 8-bytes data alignment. Keeping in mind that these commands are executed immediately after sending them (hence not chained with others before the VPU/MDP "actually" start executing), it is fine to simply add a padding of 4 bytes to this structure: this keeps the same performance as before, as we're still stack-allocating it, while avoiding hackery inside of mtk-vpu to ensure alignment bringing a definitely bigger performance impact. Fixes: c8eb2d7e8202 ("[media] media: Add Mediatek MDP Driver") Signed-off-by: AngeloGioacchino Del Regno Reviewed-by: Irui Wang --- This patch has been tested on Acer Chromebook R 13 (MT8173 Elm) on Debian Sid. This is an alternative solution to the mtk-vpu approach, found here: https://lore.kernel.org/all/20210920170408.1561-1-dafna.hirschfeld@collabora.com drivers/media/platform/mtk-mdp/mtk_mdp_ipi.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/media/platform/mtk-mdp/mtk_mdp_ipi.h b/drivers/media/platform/mtk-mdp/mtk_mdp_ipi.h index 2cb8cecb3077..b810c96695c8 100644 --- a/drivers/media/platform/mtk-mdp/mtk_mdp_ipi.h +++ b/drivers/media/platform/mtk-mdp/mtk_mdp_ipi.h @@ -40,12 +40,14 @@ struct mdp_ipi_init { * @ipi_id : IPI_MDP * @ap_inst : AP mtk_mdp_vpu address * @vpu_inst_addr : VPU MDP instance address + * @padding : Alignment padding */ struct mdp_ipi_comm { uint32_t msg_id; uint32_t ipi_id; uint64_t ap_inst; uint32_t vpu_inst_addr; + uint32_t padding; }; /**