From nobody Tue Feb 10 06:59:05 2026 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 5D79FC77B73 for ; Tue, 6 Jun 2023 11:59:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237323AbjFFL7V (ORCPT ); Tue, 6 Jun 2023 07:59:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41484 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237404AbjFFL7G (ORCPT ); Tue, 6 Jun 2023 07:59:06 -0400 Received: from mail-pg1-x52c.google.com (mail-pg1-x52c.google.com [IPv6:2607:f8b0:4864:20::52c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C65431725 for ; Tue, 6 Jun 2023 04:58:52 -0700 (PDT) Received: by mail-pg1-x52c.google.com with SMTP id 41be03b00d2f7-54290603887so2458229a12.1 for ; Tue, 06 Jun 2023 04:58:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1686052732; x=1688644732; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=/A31/i+m7BU2Bqbrm76M8ZCTI2bY2FunS+Zgw078wns=; b=NhFzPGK/LgXepWwy2zWYeTVSabXVDTmt8ct8uR0krlenAq1FVuPal+C5uyWaBMAvWB olBB/nZ90xyde17yuqRavAiVOmguy6+B6tJrxDAS6B2d4HJj9Z7J8B+GSKVW5dLTr06w gCUERydedQoK94netVwSSc1q+ZYPBfSa1XrwutHn51E9h24MMvvUO101pyo5XaYTTTsg 4tX8baj1Mxn6SJii54yc6J2GjgTg5DANSJ1qvQO0/3paMMjogfTu3oLn0+jjlHXgcYft 9H2mAY/7+/YxQBxKRBQhM8QcUxVEO1CJNM9lAFo9WztFujCmpovCta1TKGvk0/wxzeub ysNg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1686052732; x=1688644732; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=/A31/i+m7BU2Bqbrm76M8ZCTI2bY2FunS+Zgw078wns=; b=MnGXiDnhwifAyi/mRv47eU9AXlb/tZm11TNlgvj7zcRtTbtMZTudWuHxtPGkh714Yp qBf9QBf1gqKv7DhLSlDl3QcAmIDIRzLu9/DV+a7RJjs6WwhfCjR8tzsPyjD8dPbGfkUl OFVbQjK39/UZ2QBIkuvSMPhg2blTxUfk4kC4Nm3Dsuu1ingeWpPF0cdwY773V4OQJ2aR Qksgfm0ENAQVFm1pXs/7AysOffptkOf5VINGcZKrth0FZFZr/EOtWsvbAsiocxpsNQGW aCX5bxImUeCWlfBK1R6hmByCQdERlVBlXzhUVnaDNbI64giCXdjW6lsNVOblPZP0StP/ K3QA== X-Gm-Message-State: AC+VfDx4OZSuEUvjbRRxToHxnrPppd98FgAHsXGNLqqMnde3Hqg1UfO5 j21tF8SnbC9QFKm2J8gMucj6 X-Google-Smtp-Source: ACHHUZ427+RHw6YrOxFJmdnCmiR67XrtYFqFzTz2NL98BS5AZnestvUvppQJ6wrLGfIAPOyHBMZqVA== X-Received: by 2002:a05:6a21:3290:b0:10c:7c72:bdd6 with SMTP id yt16-20020a056a21329000b0010c7c72bdd6mr954741pzb.59.1686052732117; Tue, 06 Jun 2023 04:58:52 -0700 (PDT) Received: from localhost.localdomain ([117.202.186.178]) by smtp.gmail.com with ESMTPSA id b5-20020a170903228500b001acaf7e22bdsm8419226plh.14.2023.06.06.04.58.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 06 Jun 2023 04:58:51 -0700 (PDT) From: Manivannan Sadhasivam To: lpieralisi@kernel.org, kw@linux.com Cc: kishon@kernel.org, bhelgaas@google.com, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, Manivannan Sadhasivam Subject: [PATCH 6/7] PCI: epf-mhi: Use iATU for small transfers Date: Tue, 6 Jun 2023 17:28:13 +0530 Message-Id: <20230606115814.53319-7-manivannan.sadhasivam@linaro.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230606115814.53319-1-manivannan.sadhasivam@linaro.org> References: <20230606115814.53319-1-manivannan.sadhasivam@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" For transfers below 4K, let's use iATU since using eDMA for such small transfers is not efficient. This is mainly due to the fact that setting up a eDMA transfer and waiting for its completion adds some latency. This latency is negligible for large transfers but not for the smaller ones. With this hack, there is an increase in ~50Mbps throughput on both MHI UL (Uplink) and DL (Downlink) channels. Signed-off-by: Manivannan Sadhasivam --- drivers/pci/endpoint/functions/pci-epf-mhi.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/pci/endpoint/functions/pci-epf-mhi.c b/drivers/pci/end= point/functions/pci-epf-mhi.c index f4d1d60bde56..94cf68bdd235 100644 --- a/drivers/pci/endpoint/functions/pci-epf-mhi.c +++ b/drivers/pci/endpoint/functions/pci-epf-mhi.c @@ -288,6 +288,9 @@ static int pci_epf_mhi_edma_read(struct mhi_ep_cntrl *m= hi_cntrl, u64 from, dma_addr_t dst_addr; int ret; =20 + if (size < SZ_4K) + return pci_epf_mhi_iatu_read(mhi_cntrl, from, to, size); + mutex_lock(&epf_mhi->lock); =20 config.direction =3D DMA_DEV_TO_MEM; @@ -354,6 +357,9 @@ static int pci_epf_mhi_edma_write(struct mhi_ep_cntrl *= mhi_cntrl, void *from, dma_addr_t src_addr; int ret; =20 + if (size < SZ_4K) + return pci_epf_mhi_iatu_write(mhi_cntrl, from, to, size); + mutex_lock(&epf_mhi->lock); =20 config.direction =3D DMA_MEM_TO_DEV; --=20 2.25.1