From patchwork Fri Nov 24 16:02:35 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Amelie Delaunay X-Patchwork-Id: 13467831 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=foss.st.com header.i=@foss.st.com header.b="6aVF5B/r" Received: from mx07-00178001.pphosted.com (mx07-00178001.pphosted.com [185.132.182.106]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 45A671B5; Fri, 24 Nov 2023 08:02:49 -0800 (PST) Received: from pps.filterd (m0369458.ppops.net [127.0.0.1]) by mx07-00178001.pphosted.com (8.17.1.22/8.17.1.22) with ESMTP id 3AODACUB023392; Fri, 24 Nov 2023 17:02:37 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=foss.st.com; h= from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding:content-type; s=selector1; bh=FIx1Yrt cLveCC02iWnLW1Lr8XBOPNYeVOFiiPu2xIQ8=; b=6aVF5B/rBs+91n+/V8KIzyk XDKQdZDb32l89xTctlCIVYJDixYEWC8v7grnnBlwcd6sOTEG/N91HqaTlU4i0ipR +FB71z+U/SwQVPjfILaCN1dRbIeQENZE3jy4vRdXSpQ9J72EdjJaOyLVO10qJmxd Og/zjepnYR6rw80ET33vhtEot7dqrXejT3H+WcToN3osOmsV3Y+uZu2YV7NDhYT6 kZOStn7gXYmBRpWe+xN0Nmw2JhVcnAhZdZctF0BLzOI2Or9AXnwFXhxGQ2iaTjfh LYNpz0scLeyPXm8/0w1j1o+dlmhdZLConsZiFoLSCzcUXRhkcS5WQILuc2H4nPA= = 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 3uhr8ahh9y-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 24 Nov 2023 17:02:37 +0100 (CET) Received: from euls16034.sgp.st.com (euls16034.sgp.st.com [10.75.44.20]) by beta.dmz-eu.st.com (STMicroelectronics) with ESMTP id 8141310002A; Fri, 24 Nov 2023 17:02:36 +0100 (CET) Received: from Webmail-eu.st.com (shfdag1node3.st.com [10.75.129.71]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id 64A46252233; Fri, 24 Nov 2023 17:02:36 +0100 (CET) Received: from localhost (10.201.20.208) by SHFDAG1NODE3.st.com (10.75.129.71) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.27; Fri, 24 Nov 2023 17:02:36 +0100 From: Amelie Delaunay To: Vinod Koul CC: Amelie Delaunay , , Subject: [PATCH] dmaengine: dmatest: prevent using swiotlb buffer with nobounce parameter Date: Fri, 24 Nov 2023 17:02:35 +0100 Message-ID: <20231124160235.2459326-1-amelie.delaunay@foss.st.com> X-Mailer: git-send-email 2.25.1 Precedence: bulk X-Mailing-List: dmaengine@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: SHFCAS1NODE2.st.com (10.75.129.73) To SHFDAG1NODE3.st.com (10.75.129.71) X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.272,Aquarius:18.0.987,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2023-11-24_02,2023-11-22_01,2023-05-22_02 Source and destination data buffers are allocated with GPF_KERNEL flag. It means that, if the DDR is more than 2GB, buffers can be allocated above the 32-bit addressable space. In this case, and if the dma controller is only 32-bit compatible, swiotlb bounce buffer, located in the 32-bit addressable space, is used and introduces a memcpy. To prevent this extra memcpy, due to swiotlb bounce buffer use because source or destination data buffer is allocated above the 32-bit addressable space, force source and destination data buffers allocation with GPF_DMA instead, when nobounce parameter is true. Signed-off-by: Amelie Delaunay --- drivers/dma/dmatest.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/drivers/dma/dmatest.c b/drivers/dma/dmatest.c index ffe621695e47..a4f608837849 100644 --- a/drivers/dma/dmatest.c +++ b/drivers/dma/dmatest.c @@ -21,6 +21,10 @@ #include #include +static bool nobounce; +module_param(nobounce, bool, 0644); +MODULE_PARM_DESC(nobounce, "Prevent using swiotlb buffer (default: use swiotlb buffer)"); + static unsigned int test_buf_size = 16384; module_param(test_buf_size, uint, 0644); MODULE_PARM_DESC(test_buf_size, "Size of the memcpy test buffer"); @@ -90,6 +94,7 @@ MODULE_PARM_DESC(polled, "Use polling for completion instead of interrupts"); /** * struct dmatest_params - test parameters. + * @nobounce: prevent using swiotlb buffer * @buf_size: size of the memcpy test buffer * @channel: bus ID of the channel to test * @device: bus ID of the DMA Engine to test @@ -106,6 +111,7 @@ MODULE_PARM_DESC(polled, "Use polling for completion instead of interrupts"); * @polled: use polling for completion instead of interrupts */ struct dmatest_params { + bool nobounce; unsigned int buf_size; char channel[20]; char device[32]; @@ -215,6 +221,7 @@ struct dmatest_done { struct dmatest_data { u8 **raw; u8 **aligned; + gfp_t gfp_flags; unsigned int cnt; unsigned int off; }; @@ -533,7 +540,7 @@ static int dmatest_alloc_test_data(struct dmatest_data *d, goto err; for (i = 0; i < d->cnt; i++) { - d->raw[i] = kmalloc(buf_size + align, GFP_KERNEL); + d->raw[i] = kmalloc(buf_size + align, d->gfp_flags); if (!d->raw[i]) goto err; @@ -655,6 +662,13 @@ static int dmatest_func(void *data) goto err_free_coefs; } + src->gfp_flags = GFP_KERNEL; + dst->gfp_flags = GFP_KERNEL; + if (params->nobounce) { + src->gfp_flags = GFP_DMA; + dst->gfp_flags = GFP_DMA; + } + if (dmatest_alloc_test_data(src, buf_size, align) < 0) goto err_free_coefs; @@ -1093,6 +1107,7 @@ static void add_threaded_test(struct dmatest_info *info) struct dmatest_params *params = &info->params; /* Copy test parameters */ + params->nobounce = nobounce; params->buf_size = test_buf_size; strscpy(params->channel, strim(test_channel), sizeof(params->channel)); strscpy(params->device, strim(test_device), sizeof(params->device));