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 X-Spam-Level: X-Spam-Status: No, score=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 09574C433EF for ; Mon, 20 Sep 2021 15:19:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E521E61077 for ; Mon, 20 Sep 2021 15:19:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241381AbhITPVN (ORCPT ); Mon, 20 Sep 2021 11:21:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35374 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241409AbhITPU5 (ORCPT ); Mon, 20 Sep 2021 11:20:57 -0400 Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e3e3]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EC53AC061768; Mon, 20 Sep 2021 08:19:24 -0700 (PDT) Received: from [IPv6:2a02:810a:880:f54:34ca:272f:b5af:bab9] (unknown [IPv6:2a02:810a:880:f54:34ca:272f:b5af:bab9]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: dafna) by bhuna.collabora.co.uk (Postfix) with ESMTPSA id D30571F42F71; Mon, 20 Sep 2021 16:19:21 +0100 (BST) Subject: Re: [PATCH v3] media: mtk-vpu: Ensure alignment of 8 for DTCM buffer To: Hans Verkuil , linux-media@vger.kernel.org, linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Alexandre Courbot , kernel@collabora.com, Enric Balletbo i Serra , dafna3@gmail.com, mchehab@kernel.org, tfiga@chromium.org, minghsiu.tsai@mediatek.com, houlong.wei@mediatek.com, andrew-ct.chen@mediatek.com, tiffany.lin@mediatek.com, matthias.bgg@gmail.com, courbot@chromium.org, hsinyi@chromium.org, eizan@chromium.org References: <20210825101717.18075-1-dafna.hirschfeld@collabora.com> From: Dafna Hirschfeld Message-ID: <8c8336ff-57aa-dac8-d4ef-5d1dd120b2db@collabora.com> Date: Mon, 20 Sep 2021 17:19:19 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org On 01.09.21 10:50, Hans Verkuil wrote: > On 25/08/2021 12:17, Dafna Hirschfeld wrote: >> From: Alexandre Courbot >> >> When running memcpy_toio: >> memcpy_toio(send_obj->share_buf, buf, len); >> it was found that errors appear if len is not a multiple of 8: >> >> [58.350841] mtk-mdp 14001000.rdma: processing failed: -22 >> >> This patch ensures the copy of a multile of 8 size by calling > > multile -> multiple > >> round_up(len, 8) when copying >> >> Fixes: e6599adfad30 ("media: mtk-vpu: avoid unaligned access to DTCM buffer.") >> Signed-off-by: Alexandre Courbot >> Signed-off-by: Enric Balletbo i Serra >> Signed-off-by: Dafna Hirschfeld >> --- >> changes since v2: >> 1. do the extra copy only if len is not multiple of 8 >> >> changes since v1: >> 1. change sign-off-by tags >> 2. change values to memset >> >> drivers/media/platform/mtk-vpu/mtk_vpu.c | 11 ++++++++++- >> 1 file changed, 10 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/media/platform/mtk-vpu/mtk_vpu.c b/drivers/media/platform/mtk-vpu/mtk_vpu.c >> index ec290dde59cf..658161ee3e4e 100644 >> --- a/drivers/media/platform/mtk-vpu/mtk_vpu.c >> +++ b/drivers/media/platform/mtk-vpu/mtk_vpu.c >> @@ -349,7 +349,16 @@ int vpu_ipi_send(struct platform_device *pdev, >> } >> } while (vpu_cfg_readl(vpu, HOST_TO_VPU)); >> >> - memcpy_toio(send_obj->share_buf, buf, len); >> + if (len % 8 != 0) { > > You need to add a comment here explaining why this is done (basically what > you also say in the commit log). > > Otherwise people would have to dig into the git log to figure out why this > code is the way it is. > > Is len often not a multiple of 8? If that's the case, then it might be easier > to just always do the memset/memcpy. I wrote a program that prints the sizes of all possible messages: http://ix.io/3zsr compiling it to arm64 gives: sizeof(mdp_ipi_comm) is 24 sizeof(mdp_ipi_init) is 16 sizeof(venc_ap_ipi_msg_deinit) is 8 sizeof(venc_ap_ipi_msg_enc_ext) is 164 sizeof(venc_ap_ipi_msg_enc) is 32 sizeof(venc_ap_ipi_msg_set_param_ext) is 144 sizeof(venc_ap_ipi_msg_set_param) is 48 sizeof(venc_ap_ipi_msg_init) is 16 sizeof(vdec_ap_ipi_cmd) is 8 sizeof(vdec_ap_ipi_init) is 16 sizeof(vdec_ap_ipi_dec_start) is 24 BUT, when printing the size in the kernel I got "sizeof(mdp_ipi_comm) = 20" and found out that this is due to the macro #pragma pack(push, 4) in mtk_mdp_ipi.h so for mdp it makes sens to always do the memset/memcpy but for mtk-vcodec it is not necessary. In addition, if the message is one of 'venc_ap_ipi_msg_enc_ext' or 'venc_ap_ipi_msg_set_param_ext' then vpu_ipi_send will fail in the beginning of the function since in those cases we have 'len > sizeof(send_obj->share_buf)'. so I should send a patch that set SHARE_BUF_SIZE to e.g. 200 I also found out that adding #pragma pack(push, 4) to the definitions of the mtk-vcodec messages has no influence but maybe this should be added since we copy those messages to hw , so might avoid future bugs. thanks, Dafna > > Regards, > > Hans > >> + unsigned char data[SHARE_BUF_SIZE]; >> + >> + memset(data + len, 0, sizeof(data) - len); >> + memcpy(data, buf, len); >> + memcpy_toio(send_obj->share_buf, data, round_up(len, 8)); >> + } else { >> + memcpy_toio(send_obj->share_buf, buf, len); >> + } >> + >> writel(len, &send_obj->len); >> writel(id, &send_obj->id); >> >> >