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ntb_hw_switchtec: Check for alignment of the buffer in mw_set_trans()

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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>
Signed-off-by: Jon Mason <jdmason@kudzu.us>
This commit is contained in:
Logan Gunthorpe 2017-12-18 11:25:06 -07:00 committed by Jon Mason
parent cbd27448fa
commit 1e2fd202f8
1 changed files with 13 additions and 0 deletions
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13
drivers/ntb/hw/mscc/ntb_hw_switchtec.c
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@ -320,6 +320,19 @@ static int switchtec_ntb_mw_set_trans(struct ntb_dev *ntb, int pidx, int widx,
if (xlate_pos < 12)
return -EINVAL;
if (!IS_ALIGNED(addr, BIT_ULL(xlate_pos))) {
/*
* 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)