From patchwork Wed Dec 4 12:20:59 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jyothi Kumar Seerapu X-Patchwork-Id: 13893654 Received: from mx0b-0031df01.pphosted.com (mx0b-0031df01.pphosted.com [205.220.180.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3C0131ABEDC; Wed, 4 Dec 2024 12:21:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=205.220.180.131 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733314891; cv=none; b=e9jer4l2JLiQi3SaoX274d1bgGz/Emp7so31R87Ko/vinp4i76fARL9oMbLNzdXem259DUkkLiwN2OO2fvMcQusr9fe0GxZ7qUjAwrnmXHigaL3llq7v7whBTaoaRZRbCOIyw6g2hjBvzy3wHzlsrpmioNFblM2efJ5tavDncis= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733314891; c=relaxed/simple; bh=cx1zk1S4kBjz7p7iMCUMuBxe7po4tlT5K+ooJ/xdCPk=; h=From:To:CC:Subject:Date:Message-ID:MIME-Version:Content-Type; b=qhcbegMJNO3ouQSjxzEGWlEPH4W29yQMAYOW6Vc9aXBj2DkSqC3f0vkC0LPzRxLvKkC8EzJd96X2X1XKhskqrIRmJVNr6DlIxcTVNd4dMHDFvwOEan+2rYe4wjzq2vgGwgDwMV4N6ZTfBSMufLjMHPN5SGEJE7OBfotrQTnSY5A= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=quicinc.com; spf=pass smtp.mailfrom=quicinc.com; dkim=pass (2048-bit key) header.d=quicinc.com header.i=@quicinc.com header.b=C9nPCmhr; arc=none smtp.client-ip=205.220.180.131 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=quicinc.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=quicinc.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=quicinc.com header.i=@quicinc.com header.b="C9nPCmhr" Received: from pps.filterd (m0279871.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 4B47UrJP024918; Wed, 4 Dec 2024 12:21:26 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; h= cc:content-type:date:from:message-id:mime-version:subject:to; s= qcppdkim1; bh=XoiDwtSPaT4a7qV9ALXMR5OyLUjnVqX8oDegnmI+ftY=; b=C9 nPCmhrBCCyyDd834bCf3903APXrIg65KHR+UYBXCUDr9ocIYstbUNLoeu0+OGnPB 5qQ6TeFO0GzgFLLDbS/Gf70Z6a8llsEkTUB+jncOt4ApXvZ87xl5QoyBgcBpWfL8 L5iY1O9HBuu+AZBYepn6okdQe6ruglL5gN3aB1k4HtFpOzbEm73kGZ422MH/CnfG 60nVDwZjO2mtYFvazCLwJQxyPxrrYNsdOEGi9tsv+WRKsGZI1fEDifbl+B8AW7ij Wx6fWSJpGYyleHHIRi+PTgIVkz754UcuQxUb36Yes6lwcKhvSX6cEMPmUd+v2NJ4 IU7VlrRsLXX9emmx+YKg== Received: from nasanppmta01.qualcomm.com (i-global254.qualcomm.com [199.106.103.254]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 439vnyv6c9-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 04 Dec 2024 12:21:26 +0000 (GMT) Received: from nasanex01b.na.qualcomm.com (nasanex01b.na.qualcomm.com [10.46.141.250]) by NASANPPMTA01.qualcomm.com (8.18.1.2/8.18.1.2) with ESMTPS id 4B4CLHtn031571 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 4 Dec 2024 12:21:17 GMT Received: from hu-jseerapu-hyd.qualcomm.com (10.80.80.8) by nasanex01b.na.qualcomm.com (10.46.141.250) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.9; Wed, 4 Dec 2024 04:21:15 -0800 From: Jyothi Kumar Seerapu To: Vinod Koul CC: , , , , Subject: [PATCH v3] dmaengine: qcom: gpi: Add GPI immediate DMA support for SPI protocol Date: Wed, 4 Dec 2024 17:50:59 +0530 Message-ID: <20241204122059.24239-1-quic_jseerapu@quicinc.com> X-Mailer: git-send-email 2.17.1 Precedence: bulk X-Mailing-List: dmaengine@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: nasanex01a.na.qualcomm.com (10.52.223.231) To nasanex01b.na.qualcomm.com (10.46.141.250) X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-ORIG-GUID: VUlr-eGl2JDHEmj4L5o_BCpMeLYNShKp X-Proofpoint-GUID: VUlr-eGl2JDHEmj4L5o_BCpMeLYNShKp X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1039,Hydra:6.0.680,FMLib:17.12.60.29 definitions=2024-09-06_09,2024-09-06_01,2024-09-02_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 adultscore=0 mlxlogscore=999 bulkscore=0 impostorscore=0 mlxscore=0 suspectscore=0 spamscore=0 priorityscore=1501 lowpriorityscore=0 phishscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2411120000 definitions=main-2412040096 The DMA TRE(Transfer ring element) buffer contains the DMA buffer address. Accessing data from this address can cause significant delays in SPI transfers, which can be mitigated to some extent by utilizing immediate DMA support. QCOM GPI DMA hardware supports an immediate DMA feature for data up to 8 bytes, storing the data directly in the DMA TRE buffer instead of the DMA buffer address. This enhancement enables faster SPI data transfers. This optimization reduces the average transfer time from 25 us to 16 us for a single SPI transfer of 8 bytes length, with a clock frequency of 50 MHz. Signed-off-by: Jyothi Kumar Seerapu --- v2-> v3: - When to enable Immediate DMA support, control is moved to GPI driver from SPI driver. - Optimizations are done in GPI driver related to immediate dma changes. - Removed the immediate dma supported changes in qcom-gpi-dma.h file and handled in GPI driver. Link to v2: https://lore.kernel.org/all/20241128133351.24593-2-quic_jseerapu@quicinc.com/ https://lore.kernel.org/all/20241128133351.24593-3-quic_jseerapu@quicinc.com/ v1 -> v2: - Separated the patches to dmaengine and spi subsystems - Removed the changes which are not required for this feature from qcom-gpi-dma.h file. - Removed the type conversions used in gpi_create_spi_tre. Link to v1: https://lore.kernel.org/lkml/20241121115201.2191-2-quic_jseerapu@quicinc.com/ drivers/dma/qcom/gpi.c | 32 +++++++++++++++++++++++++++----- 1 file changed, 27 insertions(+), 5 deletions(-) diff --git a/drivers/dma/qcom/gpi.c b/drivers/dma/qcom/gpi.c index 52a7c8f2498f..35451d5a81f7 100644 --- a/drivers/dma/qcom/gpi.c +++ b/drivers/dma/qcom/gpi.c @@ -27,6 +27,7 @@ #define TRE_FLAGS_IEOT BIT(9) #define TRE_FLAGS_BEI BIT(10) #define TRE_FLAGS_LINK BIT(11) +#define TRE_FLAGS_IMMEDIATE_DMA BIT(16) #define TRE_FLAGS_TYPE GENMASK(23, 16) /* SPI CONFIG0 WD0 */ @@ -64,6 +65,7 @@ /* DMA TRE */ #define TRE_DMA_LEN GENMASK(23, 0) +#define TRE_DMA_IMMEDIATE_LEN GENMASK(3, 0) /* Register offsets from gpi-top */ #define GPII_n_CH_k_CNTXT_0_OFFS(n, k) (0x20000 + (0x4000 * (n)) + (0x80 * (k))) @@ -1711,6 +1713,8 @@ static int gpi_create_spi_tre(struct gchan *chan, struct gpi_desc *desc, dma_addr_t address; struct gpi_tre *tre; unsigned int i; + int len; + u8 immediate_dma; /* first create config tre if applicable */ if (direction == DMA_MEM_TO_DEV && spi->set_config) { @@ -1763,14 +1767,32 @@ static int gpi_create_spi_tre(struct gchan *chan, struct gpi_desc *desc, tre_idx++; address = sg_dma_address(sgl); - tre->dword[0] = lower_32_bits(address); - tre->dword[1] = upper_32_bits(address); + len = sg_dma_len(sgl); - tre->dword[2] = u32_encode_bits(sg_dma_len(sgl), TRE_DMA_LEN); + immediate_dma = (direction == DMA_MEM_TO_DEV) && len <= 2 * sizeof(tre->dword[0]); + + /* Support Immediate dma for write transfers for data length up to 8 bytes */ + if (immediate_dma) { + /* + * For Immediate dma, data length may not always be length of 8 bytes, + * it can be length less than 8, hence initialize both dword's with 0 + */ + tre->dword[0] = 0; + tre->dword[1] = 0; + memcpy(&tre->dword[0], sg_virt(sgl), len); + + tre->dword[2] = u32_encode_bits(len, TRE_DMA_IMMEDIATE_LEN); + } else { + tre->dword[0] = lower_32_bits(address); + tre->dword[1] = upper_32_bits(address); + + tre->dword[2] = u32_encode_bits(len, TRE_DMA_LEN); + } tre->dword[3] = u32_encode_bits(TRE_TYPE_DMA, TRE_FLAGS_TYPE); - if (direction == DMA_MEM_TO_DEV) - tre->dword[3] |= u32_encode_bits(1, TRE_FLAGS_IEOT); + tre->dword[3] |= u32_encode_bits(!!immediate_dma, TRE_FLAGS_IMMEDIATE_DMA); + tre->dword[3] |= u32_encode_bits(!!(direction == DMA_MEM_TO_DEV), + TRE_FLAGS_IEOT); for (i = 0; i < tre_idx; i++) dev_dbg(dev, "TRE:%d %x:%x:%x:%x\n", i, desc->tre[i].dword[0],