From patchwork Thu Mar 17 11:19:44 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yann Gautier X-Patchwork-Id: 12783897 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 79C43C4332F for ; Thu, 17 Mar 2022 11:20:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232926AbiCQLVT (ORCPT ); Thu, 17 Mar 2022 07:21:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40928 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232907AbiCQLVS (ORCPT ); Thu, 17 Mar 2022 07:21:18 -0400 Received: from mx07-00178001.pphosted.com (mx07-00178001.pphosted.com [185.132.182.106]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5CAB61E3747; Thu, 17 Mar 2022 04:20:02 -0700 (PDT) Received: from pps.filterd (m0241204.ppops.net [127.0.0.1]) by mx07-00178001.pphosted.com (8.16.1.2/8.16.1.2) with ESMTP id 22H8ajDR013555; Thu, 17 Mar 2022 12:19:53 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=foss.st.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding : content-type; s=selector1; bh=kAMja3mzzrpLLGndAp+sD7LqFYqH/O9HbNw7JoUs1Mo=; b=Iq7CwlnV74D0SaIzrCKYMIHXcbzx5GufDgXp17MkPR4yTT5w3k+iEln6f7AnnIV+rY7r XrAoDE2YvCxC8u1Nnm1kl6fu8e04UR/25O40QcogLUx9KW0VXUf7MqPz9CmErdoeNDme au6VqXe0vzQuXXd1Ri573PmkR5m5UVGkH/iuZdSh4Ds9Zs+RCBpvY/khUe/LHry9cnn8 BJhl2+QbT5UHBfhtpb6bWdsg311iCwc/UrO5LXBILpKxoQpDhfUBDMplrYOTqlmgFWeV mkI7K3GJ3lAUo9Jc6mEoSYGmoGyc89+EyOCICrXRXaxQPEIVCiBzI/+GUrqnUSgG59e6 1Q== Received: from beta.dmz-eu.st.com (beta.dmz-eu.st.com [164.129.1.35]) by mx07-00178001.pphosted.com (PPS) with ESMTPS id 3et63hm7pm-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 17 Mar 2022 12:19:53 +0100 Received: from euls16034.sgp.st.com (euls16034.sgp.st.com [10.75.44.20]) by beta.dmz-eu.st.com (STMicroelectronics) with ESMTP id F10AB100038; Thu, 17 Mar 2022 12:19:51 +0100 (CET) Received: from Webmail-eu.st.com (sfhdag2node2.st.com [10.75.127.5]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id E827A217B69; Thu, 17 Mar 2022 12:19:51 +0100 (CET) Received: from localhost (10.75.127.44) by SFHDAG2NODE2.st.com (10.75.127.5) with Microsoft SMTP Server (TLS) id 15.0.1497.26; Thu, 17 Mar 2022 12:19:51 +0100 From: Yann Gautier To: Ulf Hansson CC: Christophe Kerello , Ludovic Barre , Maxime Coquelin , Alexandre Torgue , Philipp Zabel , Linus Walleij , , , , , Yann Gautier Subject: [PATCH 2/2] mmc: mmci: stm32: use a buffer for unaligned DMA requests Date: Thu, 17 Mar 2022 12:19:44 +0100 Message-ID: <20220317111944.116148-3-yann.gautier@foss.st.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220317111944.116148-1-yann.gautier@foss.st.com> References: <20220317111944.116148-1-yann.gautier@foss.st.com> MIME-Version: 1.0 X-Originating-IP: [10.75.127.44] X-ClientProxiedBy: SFHDAG2NODE2.st.com (10.75.127.5) To SFHDAG2NODE2.st.com (10.75.127.5) X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.850,Hydra:6.0.425,FMLib:17.11.64.514 definitions=2022-03-17_04,2022-03-15_01,2022-02-23_01 Precedence: bulk List-ID: X-Mailing-List: linux-mmc@vger.kernel.org In SDIO mode, the sg list for requests can be unaligned with what the STM32 SDMMC internal DMA can support. In that case, instead of failing, use a temporary bounce buffer to copy from/to the sg list. This buffer is limited to 1MB. But for that we need to also limit max_req_size to 1MB. It has not shown any throughput penalties for SD-cards or eMMC. Signed-off-by: Yann Gautier --- drivers/mmc/host/mmci_stm32_sdmmc.c | 80 +++++++++++++++++++++++------ 1 file changed, 63 insertions(+), 17 deletions(-) diff --git a/drivers/mmc/host/mmci_stm32_sdmmc.c b/drivers/mmc/host/mmci_stm32_sdmmc.c index 4566d7fc9055..a4414e32800f 100644 --- a/drivers/mmc/host/mmci_stm32_sdmmc.c +++ b/drivers/mmc/host/mmci_stm32_sdmmc.c @@ -43,6 +43,9 @@ struct sdmmc_lli_desc { struct sdmmc_idma { dma_addr_t sg_dma; void *sg_cpu; + dma_addr_t bounce_dma_addr; + void *bounce_buf; + bool use_bounce_buffer; }; struct sdmmc_dlyb { @@ -54,6 +57,7 @@ struct sdmmc_dlyb { static int sdmmc_idma_validate_data(struct mmci_host *host, struct mmc_data *data) { + struct sdmmc_idma *idma = host->dma_priv; struct scatterlist *sg; int i; @@ -61,21 +65,23 @@ static int sdmmc_idma_validate_data(struct mmci_host *host, * idma has constraints on idmabase & idmasize for each element * excepted the last element which has no constraint on idmasize */ + idma->use_bounce_buffer = false; for_each_sg(data->sg, sg, data->sg_len - 1, i) { if (!IS_ALIGNED(sg->offset, sizeof(u32)) || !IS_ALIGNED(sg->length, SDMMC_IDMA_BURST)) { - dev_err(mmc_dev(host->mmc), + dev_dbg(mmc_dev(host->mmc), "unaligned scatterlist: ofst:%x length:%d\n", data->sg->offset, data->sg->length); - return -EINVAL; + idma->use_bounce_buffer = true; + return 0; } } if (!IS_ALIGNED(sg->offset, sizeof(u32))) { - dev_err(mmc_dev(host->mmc), + dev_dbg(mmc_dev(host->mmc), "unaligned last scatterlist: ofst:%x length:%d\n", data->sg->offset, data->sg->length); - return -EINVAL; + idma->use_bounce_buffer = true; } return 0; @@ -84,18 +90,29 @@ static int sdmmc_idma_validate_data(struct mmci_host *host, static int _sdmmc_idma_prep_data(struct mmci_host *host, struct mmc_data *data) { - int n_elem; + struct sdmmc_idma *idma = host->dma_priv; - n_elem = dma_map_sg(mmc_dev(host->mmc), - data->sg, - data->sg_len, - mmc_get_dma_dir(data)); + if (idma->use_bounce_buffer) { + if (data->flags & MMC_DATA_WRITE) { + unsigned int xfer_bytes = data->blksz * data->blocks; - if (!n_elem) { - dev_err(mmc_dev(host->mmc), "dma_map_sg failed\n"); - return -EINVAL; - } + sg_copy_to_buffer(data->sg, data->sg_len, + idma->bounce_buf, xfer_bytes); + dma_wmb(); + } + } else { + int n_elem; + + n_elem = dma_map_sg(mmc_dev(host->mmc), + data->sg, + data->sg_len, + mmc_get_dma_dir(data)); + if (!n_elem) { + dev_err(mmc_dev(host->mmc), "dma_map_sg failed\n"); + return -EINVAL; + } + } return 0; } @@ -112,8 +129,19 @@ static int sdmmc_idma_prep_data(struct mmci_host *host, static void sdmmc_idma_unprep_data(struct mmci_host *host, struct mmc_data *data, int err) { - dma_unmap_sg(mmc_dev(host->mmc), data->sg, data->sg_len, - mmc_get_dma_dir(data)); + struct sdmmc_idma *idma = host->dma_priv; + + if (idma->use_bounce_buffer) { + if (data->flags & MMC_DATA_READ) { + unsigned int xfer_bytes = data->blksz * data->blocks; + + sg_copy_from_buffer(data->sg, data->sg_len, + idma->bounce_buf, xfer_bytes); + } + } else { + dma_unmap_sg(mmc_dev(host->mmc), data->sg, data->sg_len, + mmc_get_dma_dir(data)); + } } static int sdmmc_idma_setup(struct mmci_host *host) @@ -137,6 +165,16 @@ static int sdmmc_idma_setup(struct mmci_host *host) host->mmc->max_segs = SDMMC_LLI_BUF_LEN / sizeof(struct sdmmc_lli_desc); host->mmc->max_seg_size = host->variant->stm32_idmabsize_mask; + + host->mmc->max_req_size = SZ_1M; + idma->bounce_buf = dmam_alloc_coherent(dev, + host->mmc->max_req_size, + &idma->bounce_dma_addr, + GFP_KERNEL); + if (!idma->bounce_buf) { + dev_err(dev, "Unable to map allocate DMA bounce buffer.\n"); + return -ENOMEM; + } } else { host->mmc->max_segs = 1; host->mmc->max_seg_size = host->mmc->max_req_size; @@ -154,8 +192,16 @@ static int sdmmc_idma_start(struct mmci_host *host, unsigned int *datactrl) struct scatterlist *sg; int i; - if (!host->variant->dma_lli || data->sg_len == 1) { - writel_relaxed(sg_dma_address(data->sg), + if (!host->variant->dma_lli || data->sg_len == 1 || + idma->use_bounce_buffer) { + u32 dma_addr; + + if (idma->use_bounce_buffer) + dma_addr = idma->bounce_dma_addr; + else + dma_addr = sg_dma_address(data->sg); + + writel_relaxed(dma_addr, host->base + MMCI_STM32_IDMABASE0R); writel_relaxed(MMCI_STM32_IDMAEN, host->base + MMCI_STM32_IDMACTRLR);