From patchwork Fri Mar 31 11:49:50 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vignesh Raghavendra X-Patchwork-Id: 9656107 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 9912160349 for ; Fri, 31 Mar 2017 11:58:06 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 89B9228650 for ; Fri, 31 Mar 2017 11:58:06 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 7C8D128678; Fri, 31 Mar 2017 11:58:06 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,T_DKIM_INVALID autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B450028678 for ; Fri, 31 Mar 2017 11:58:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933087AbdCaL5q (ORCPT ); Fri, 31 Mar 2017 07:57:46 -0400 Received: from lelnx194.ext.ti.com ([198.47.27.80]:45300 "EHLO lelnx194.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932729AbdCaL5n (ORCPT ); Fri, 31 Mar 2017 07:57:43 -0400 Received: from dflxv15.itg.ti.com ([128.247.5.124]) by lelnx194.ext.ti.com (8.15.1/8.15.1) with ESMTP id v2VBvd7i017065; Fri, 31 Mar 2017 06:57:39 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ti.com; s=ti-com-17Q1; t=1490961459; bh=KWYSe/AlzKgUN+fzN5X6OiW4CGmUVB1CzuISrnf85GA=; h=From:To:CC:Subject:Date:In-Reply-To:References; b=MaWBI5qZ2/HtFN3vpNBmJzGs99WkYteoFFwQycQSWgYQf5v1FxhHZSCMhrOHTjFjW aLrrwwz4ikn1XFUJRKrX3ieyaYCYxWyyD3pvD9UnhWBLCapqvHIb/wpSsiqJhvtvkv 5VPoFKyGr0+uhYLVB3dBG4MqbeX20rimH+t61hQI= Received: from DFLE72.ent.ti.com (dfle72.ent.ti.com [128.247.5.109]) by dflxv15.itg.ti.com (8.14.3/8.13.8) with ESMTP id v2VBvdlr012703; Fri, 31 Mar 2017 06:57:39 -0500 Received: from dflp33.itg.ti.com (10.64.6.16) by DFLE72.ent.ti.com (128.247.5.109) with Microsoft SMTP Server id 14.3.294.0; Fri, 31 Mar 2017 06:57:39 -0500 Received: from a0132425.india.ti.com (ileax41-snat.itg.ti.com [10.172.224.153]) by dflp33.itg.ti.com (8.14.3/8.13.8) with ESMTP id v2VBvXVH029992; Fri, 31 Mar 2017 06:57:37 -0500 From: Vignesh R To: Mark Brown CC: , , , Vignesh R Subject: [PATCH 2/2] spi: spi-ti-qspi: Use bounce buffer if read buffer is not DMA'ble Date: Fri, 31 Mar 2017 17:19:50 +0530 Message-ID: <20170331114950.21489-3-vigneshr@ti.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170331114950.21489-1-vigneshr@ti.com> References: <20170331114950.21489-1-vigneshr@ti.com> MIME-Version: 1.0 Sender: linux-spi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Flash filesystems like JFFS2, UBIFS and MTD block layer can provide vmalloc'd or kmap'd buffers that cannot be mapped using dma_map_sg() and can potentially be in memory region above 32bit addressable region(ie buffers belonging to memory region backed by LPAE) of DMA, implement spi_flash_can_dma() interface to inform SPI core not to map such buffers. When buffers are not mapped for DMA, then use a pre allocated bounce buffer(64K = typical flash erase sector size) to read from flash and then do a copy to actual destination buffer. This is approach is much faster than using memcpy using CPU and also reduces CPU load. With this patch, UBIFS read speed is ~18MB/s and CPU utilization <20% on DRA74 Rev H EVM. Performance degradation is negligible when compared with non bounce buffer case while using UBIFS. Signed-off-by: Vignesh R --- drivers/spi/spi-ti-qspi.c | 64 +++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 57 insertions(+), 7 deletions(-) diff --git a/drivers/spi/spi-ti-qspi.c b/drivers/spi/spi-ti-qspi.c index 7b39bc204a30..dce6ce634143 100644 --- a/drivers/spi/spi-ti-qspi.c +++ b/drivers/spi/spi-ti-qspi.c @@ -57,6 +57,8 @@ struct ti_qspi { struct ti_qspi_regs ctx_reg; dma_addr_t mmap_phys_base; + dma_addr_t rx_bb_dma_addr; + void *rx_bb_addr; struct dma_chan *rx_chan; u32 spi_max_frequency; @@ -126,6 +128,8 @@ struct ti_qspi { #define QSPI_SETUP_ADDR_SHIFT 8 #define QSPI_SETUP_DUMMY_SHIFT 10 +#define QSPI_DMA_BUFFER_SIZE 65536U + static inline unsigned long ti_qspi_read(struct ti_qspi *qspi, unsigned long reg) { @@ -429,6 +433,34 @@ static int ti_qspi_dma_xfer(struct ti_qspi *qspi, dma_addr_t dma_dst, return 0; } +static int ti_qspi_dma_bounce_buffer(struct ti_qspi *qspi, + struct spi_flash_read_message *msg) +{ + size_t readsize = msg->len; + unsigned int to = (unsigned int)msg->buf; + dma_addr_t dma_src = qspi->mmap_phys_base + msg->from; + int ret = 0; + + /* + * Use bounce buffer as FS like jffs2, ubifs may pass + * buffers that does not belong to kernel lowmem region. + */ + while (readsize != 0) { + size_t xfer_len = min(QSPI_DMA_BUFFER_SIZE, readsize); + + ret = ti_qspi_dma_xfer(qspi, qspi->rx_bb_dma_addr, + dma_src, xfer_len); + if (ret != 0) + return ret; + memcpy((void *)to, qspi->rx_bb_addr, xfer_len); + readsize -= xfer_len; + dma_src += xfer_len; + to += xfer_len; + } + + return ret; +} + static int ti_qspi_dma_xfer_sg(struct ti_qspi *qspi, struct sg_table rx_sg, loff_t from) { @@ -496,6 +528,12 @@ static void ti_qspi_setup_mmap_read(struct spi_device *spi, QSPI_SPI_SETUP_REG(spi->chip_select)); } +static bool ti_qspi_spi_flash_can_dma(struct spi_device *spi, + struct spi_flash_read_message *msg) +{ + return virt_addr_valid(msg->buf); +} + static int ti_qspi_spi_flash_read(struct spi_device *spi, struct spi_flash_read_message *msg) { @@ -509,15 +547,12 @@ static int ti_qspi_spi_flash_read(struct spi_device *spi, ti_qspi_setup_mmap_read(spi, msg); if (qspi->rx_chan) { - if (msg->cur_msg_mapped) { + if (msg->cur_msg_mapped) ret = ti_qspi_dma_xfer_sg(qspi, msg->rx_sg, msg->from); - if (ret) - goto err_unlock; - } else { - dev_err(qspi->dev, "Invalid address for DMA\n"); - ret = -EIO; + else + ret = ti_qspi_dma_bounce_buffer(qspi, msg); + if (ret) goto err_unlock; - } } else { memcpy_fromio(msg->buf, qspi->mmap_base + msg->from, msg->len); } @@ -723,6 +758,17 @@ static int ti_qspi_probe(struct platform_device *pdev) ret = 0; goto no_dma; } + qspi->rx_bb_addr = dma_alloc_coherent(qspi->dev, + QSPI_DMA_BUFFER_SIZE, + &qspi->rx_bb_dma_addr, + GFP_KERNEL | GFP_DMA); + if (!qspi->rx_bb_addr) { + dev_err(qspi->dev, + "dma_alloc_coherent failed, using PIO mode\n"); + dma_release_channel(qspi->rx_chan); + goto no_dma; + } + master->spi_flash_can_dma = ti_qspi_spi_flash_can_dma; master->dma_rx = qspi->rx_chan; init_completion(&qspi->transfer_complete); if (res_mmap) @@ -763,6 +809,10 @@ static int ti_qspi_remove(struct platform_device *pdev) pm_runtime_put_sync(&pdev->dev); pm_runtime_disable(&pdev->dev); + if (qspi->rx_bb_addr) + dma_free_coherent(qspi->dev, QSPI_DMA_BUFFER_SIZE, + qspi->rx_bb_addr, + qspi->rx_bb_dma_addr); if (qspi->rx_chan) dma_release_channel(qspi->rx_chan);