Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 3cc5ba19 authored by Dave Jiang's avatar Dave Jiang Committed by Jon Mason
Browse files

ntb: Add alignment check to meet hardware requirement 



The NTB translate register must have the value to be BAR size aligned.
This alignment check make sure that the DMA memory allocated has the
proper alignment. Another requirement for NTB to function properly with
memory window BAR size greater or equal to 4M is to use the CMA feature
in 3.16 kernel with the appropriate CONFIG_CMA_ALIGNMENT and
CONFIG_CMA_SIZE_MBYTES set.

Signed-off-by: default avatarDave Jiang <dave.jiang@intel.com>
Signed-off-by: default avatarJon Mason <jdmason@kudzu.us>
parent 9ef6bf6c

drivers/ntb/ntb_transport.c

+13 −0
Original line number Diff line number Diff line
@@ -576,6 +576,19 @@ static int ntb_set_mw(struct ntb_transport *nt, int num_mw, unsigned int size) 
		return -ENOMEM;

	}



	/*

	 * we must ensure that the memory address allocated is BAR size

	 * aligned in order for the XLAT register to take the value. This

	 * is a requirement of the hardware. It is recommended to setup CMA

	 * for BAR sizes equal or greater than 4MB.

	 */

	if (!IS_ALIGNED(mw->dma_addr, mw->size)) {

		dev_err(&pdev->dev, "DMA memory %pad not aligned to BAR size\n",

			&mw->dma_addr);

		ntb_free_mw(nt, num_mw);

		return -ENOMEM;

	}



	/* Notify HW the memory location of the receive buffer */

	ntb_set_mw_addr(nt->ndev, num_mw, mw->dma_addr);