From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:56266 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753411AbdGCMaa (ORCPT ); Mon, 3 Jul 2017 08:30:30 -0400 Subject: Patch "spi: When no dma_chan map buffers with spi_master's parent" has been added to the 4.9-stable tree To: djkurtz@chromium.org, broonie@kernel.org, gregkh@linuxfoundation.org, leilk.liu@mediatek.com Cc: , From: Date: Mon, 03 Jul 2017 14:30:12 +0200 Message-ID: <149908501253176@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled spi: When no dma_chan map buffers with spi_master's parent to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: spi-when-no-dma_chan-map-buffers-with-spi_master-s-parent.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 88b0aa544af58ce3be125a1845a227264ec9ab89 Mon Sep 17 00:00:00 2001 From: Daniel Kurtz Date: Fri, 27 Jan 2017 00:21:53 +0800 Subject: spi: When no dma_chan map buffers with spi_master's parent From: Daniel Kurtz commit 88b0aa544af58ce3be125a1845a227264ec9ab89 upstream. Back before commit 1dccb598df54 ("arm64: simplify dma_get_ops"), for arm64, devices for which dma_ops were not explicitly set were automatically configured to use swiotlb_dma_ops, since this was hard-coded as the global "dma_ops" in arm64_dma_init(). Now that global "dma_ops" has been removed, all devices much have their dma_ops explicitly set by a call to arch_setup_dma_ops(), otherwise the device is assigned dummy_dma_ops, and thus calls to map_sg for such a device will fail (return 0). Mediatek SPI uses DMA but does not use a dma channel. Support for this was added by commit c37f45b5f1cd ("spi: support spi without dma channel to use can_dma()"), which uses the master_spi dev to DMA map buffers. The master_spi device is not a platform device, rather it is created in spi_alloc_device(), and therefore its dma_ops are never set. Therefore, when the mediatek SPI driver when it does DMA (for large SPI transactions > 32 bytes), SPI will use spi_map_buf()->dma_map_sg() to map the buffer for use in DMA. But dma_map_sg()->dma_map_sg_attrs() returns 0, because ops->map_sg is dummy_dma_ops->__dummy_map_sg, and hence spi_map_buf() returns -ENOMEM (-12). Fix this by using the real spi_master's parent device which should be a real physical device with DMA properties. Signed-off-by: Daniel Kurtz Fixes: c37f45b5f1cd ("spi: support spi without dma channel to use can_dma()") Cc: Leilk Liu Signed-off-by: Mark Brown Signed-off-by: Greg Kroah-Hartman --- drivers/spi/spi.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -797,12 +797,12 @@ static int __spi_map_msg(struct spi_mast if (master->dma_tx) tx_dev = master->dma_tx->device->dev; else - tx_dev = &master->dev; + tx_dev = master->dev.parent; if (master->dma_rx) rx_dev = master->dma_rx->device->dev; else - rx_dev = &master->dev; + rx_dev = master->dev.parent; list_for_each_entry(xfer, &msg->transfers, transfer_list) { if (!master->can_dma(master, msg->spi, xfer)) @@ -844,12 +844,12 @@ static int __spi_unmap_msg(struct spi_ma if (master->dma_tx) tx_dev = master->dma_tx->device->dev; else - tx_dev = &master->dev; + tx_dev = master->dev.parent; if (master->dma_rx) rx_dev = master->dma_rx->device->dev; else - rx_dev = &master->dev; + rx_dev = master->dev.parent; list_for_each_entry(xfer, &msg->transfers, transfer_list) { if (!master->can_dma(master, msg->spi, xfer)) Patches currently in stable-queue which might be from djkurtz@chromium.org are queue-4.9/spi-when-no-dma_chan-map-buffers-with-spi_master-s-parent.patch