From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ale.deltatee.com (ale.deltatee.com. [207.54.116.67]) by gmr-mx.google.com with ESMTPS id g129si245408itd.1.2017.12.08.16.02.23 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 08 Dec 2017 16:02:23 -0800 (PST) From: Logan Gunthorpe Date: Fri, 8 Dec 2017 17:02:17 -0700 Message-Id: <20171209000217.18366-2-logang@deltatee.com> In-Reply-To: <20171209000217.18366-1-logang@deltatee.com> References: <20171209000217.18366-1-logang@deltatee.com> Subject: [PATCH 2/2] ntb_hw_switchtec: Check for alignment of the buffer in mw_set_trans() To: linux-ntb@googlegroups.com, linux-kernel@vger.kernel.org Cc: Logan Gunthorpe , Jon Mason List-ID: With Switchtec hardware, the buffer used for a memory window must be aligned to its size (the hardware only replaces the lower bits). In certain circumstances dma_alloc_coherent() will not provide a buffer that adheres to this requirement like when using the CMA and CONFIG_CMA_ALIGNMENT is set lower than the buffer size. When we get an unaligned buffer mw_set_trans() should return an error. We also log an error so we know the cause of the problem. Signed-off-by: Logan Gunthorpe Cc: Jon Mason --- drivers/ntb/hw/mscc/ntb_hw_switchtec.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/drivers/ntb/hw/mscc/ntb_hw_switchtec.c b/drivers/ntb/hw/mscc/ntb_hw_switchtec.c index 709f37fbe232..984b83bc7dd3 100644 --- a/drivers/ntb/hw/mscc/ntb_hw_switchtec.c +++ b/drivers/ntb/hw/mscc/ntb_hw_switchtec.c @@ -315,6 +315,19 @@ static int switchtec_ntb_mw_set_trans(struct ntb_dev *ntb, int pidx, int widx, if (xlate_pos < 12) return -EINVAL; + if (addr & ((1 << xlate_pos) - 1)) { + /* + * In certain circumstances we can get a buffer that is + * not aligned to its size. (Most of the time + * dma_alloc_coherent ensures this). This can happen when + * using large buffers allocated by the CMA + * (see CMA_CONFIG_ALIGNMENT) + */ + dev_err(&sndev->stdev->dev, + "ERROR: Memory window address is not aligned to it's size!\n"); + return -EINVAL; + } + rc = switchtec_ntb_part_op(sndev, ctl, NTB_CTRL_PART_OP_LOCK, NTB_CTRL_PART_STATUS_LOCKED); if (rc) -- 2.11.0