From: Logan Gunthorpe <logang@deltatee.com>
To: linux-ntb@googlegroups.com, linux-kernel@vger.kernel.org
Cc: Logan Gunthorpe <logang@deltatee.com>, Jon Mason <jdmason@kudzu.us>
Subject: [PATCH 2/2] ntb_hw_switchtec: Check for alignment of the buffer in mw_set_trans()
Date: Fri, 8 Dec 2017 17:02:17 -0700 [thread overview]
Message-ID: <20171209000217.18366-2-logang@deltatee.com> (raw)
In-Reply-To: <20171209000217.18366-1-logang@deltatee.com>
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 <logang@deltatee.com>
Cc: Jon Mason <jdmason@kudzu.us>
---
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
next prev parent reply other threads:[~2017-12-09 0:02 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-09 0:02 [PATCH 1/2] ntb_transport: Fix bug with max_mw_size parameter Logan Gunthorpe
2017-12-09 0:02 ` Logan Gunthorpe [this message]
2017-12-11 14:58 ` [PATCH 2/2] ntb_hw_switchtec: Check for alignment of the buffer in mw_set_trans() Allen Hubbe
2017-12-11 17:14 ` Logan Gunthorpe
2017-12-11 19:17 ` Allen Hubbe
2017-12-11 19:28 ` Logan Gunthorpe
2017-12-11 20:06 ` Allen Hubbe
2017-12-11 20:38 ` Logan Gunthorpe
2017-12-11 14:55 ` [PATCH 1/2] ntb_transport: Fix bug with max_mw_size parameter Allen Hubbe
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