Commit 1e2fd202 authored Dec 18, 2017 by Logan Gunthorpe Committed by Jon Mason Jan 28, 2018

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



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>

parent cbd27448

drivers/ntb/hw/mscc/ntb_hw_switchtec.c

+13 −0

Original line number	Diff line number	Diff line
		@@ -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)