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Commit 1033b3ea authored by Michael Buesch's avatar Michael Buesch Committed by John W. Linville
Browse files

b43: Workaround DMA quirks 



Some mainboards/CPUs don't allow DMA masks bigger than a certain limit.
Some VIA crap^h^h^h^hdevices have an upper limit of 0xFFFFFFFF. So in this
case a 64-bit b43 device would always fail to acquire the mask.
Implement a workaround to fallback to lower DMA mask, as we can always
also support a lower mask.

Signed-off-by: default avatarMichael Buesch <mb@bu3sch.de>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 0da926f0

drivers/net/wireless/b43/dma.c

+39 −8
Original line number Diff line number Diff line
@@ -980,6 +980,42 @@ void b43_dma_free(struct b43_wldev *dev) 
	destroy_ring(dma, tx_ring_mcast);

}



static int b43_dma_set_mask(struct b43_wldev *dev, u64 mask)

{

	u64 orig_mask = mask;

	bool fallback = 0;

	int err;



	/* Try to set the DMA mask. If it fails, try falling back to a

	 * lower mask, as we can always also support a lower one. */

	while (1) {

		err = ssb_dma_set_mask(dev->dev, mask);

		if (!err)

			break;

		if (mask == DMA_64BIT_MASK) {

			mask = DMA_32BIT_MASK;

			fallback = 1;

			continue;

		}

		if (mask == DMA_32BIT_MASK) {

			mask = DMA_30BIT_MASK;

			fallback = 1;

			continue;

		}

		b43err(dev->wl, "The machine/kernel does not support "

		       "the required %u-bit DMA mask\n",

		       (unsigned int)dma_mask_to_engine_type(orig_mask));

		return -EOPNOTSUPP;

	}

	if (fallback) {

		b43info(dev->wl, "DMA mask fallback from %u-bit to %u-bit\n",

			(unsigned int)dma_mask_to_engine_type(orig_mask),

			(unsigned int)dma_mask_to_engine_type(mask));

	}



	return 0;

}



int b43_dma_init(struct b43_wldev *dev)

{

	struct b43_dma *dma = &dev->dma;
@@ -989,14 +1025,9 @@ int b43_dma_init(struct b43_wldev *dev) 


	dmamask = supported_dma_mask(dev);

	type = dma_mask_to_engine_type(dmamask);

	err = ssb_dma_set_mask(dev->dev, dmamask);

	if (err) {

		b43err(dev->wl, "The machine/kernel does not support "

		       "the required DMA mask (0x%08X%08X)\n",

		       (unsigned int)((dmamask & 0xFFFFFFFF00000000ULL) >> 32),

		       (unsigned int)(dmamask & 0x00000000FFFFFFFFULL));

		return -EOPNOTSUPP;

	}

	err = b43_dma_set_mask(dev, dmamask);

	if (err)

		return err;



	err = -ENOMEM;

	/* setup TX DMA channels. */