Re: [PATCH V9 1/4] dma-mapping: Rework dma_get_cache_alignment()

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Hi Huacai,

On 2017-10-25 03:22, 陈华才 wrote:
Hi, Marek

Patch3 is needed for stable, but Patch3 depend on Patch1 and Patch2.

Then patch #3 has to be reworked. First change scsi to align the block queue to dma_get_cache_alignment(). This will be safe in all cases and it will not hurt memory usage that much. Such version can be applied first and sent to stable without any dependencies. Please also describe deeply why such change is needed and what issues can be observed without it, on which systems.

Then as an optimization add support for per-device cache_alignment (patches #1 and #2). I'm still not convinced that it makes sense to align DMA structures to values less than L1 cache line size. It might hurt performance, because cache coherency has its cost and it is also relevant to multi-core/smp access to any objects that are in the same l1 cache line. Memory savings that might be the results of such lower alignment are probably negligible.


Huacai
------------------ Original ------------------
From:  "Marek Szyprowski"<m.szyprowski@xxxxxxxxxxx>;
Date:  Tue, Oct 24, 2017 09:30 PM
To:  "Huacai Chen"<chenhc@xxxxxxxxxx>; "Christoph Hellwig"<hch@xxxxxx>;
Cc:  "Robin Murphy"<robin.murphy@xxxxxxx>; "Andrew Morton"<akpm@xxxxxxxxxxxxxxxxxxxx>; "Fuxin Zhang"<zhangfx@xxxxxxxxxx>; "linux-kernel"<linux-kernel@xxxxxxxxxxxxxxx>; "Ralf Baechle"<ralf@xxxxxxxxxxxxxx>; "JamesHogan"<james.hogan@xxxxxxxxxx>; "linux-mips"<linux-mips@xxxxxxxxxxxxxx>; "James E . J .Bottomley"<jejb@xxxxxxxxxxxxxxxxxx>; "Martin K . Petersen"<martin.petersen@xxxxxxxxxx>; "linux-scsi"<linux-scsi@xxxxxxxxxxxxxxx>; "stable"<stable@xxxxxxxxxxxxxxx>; "Michael S . Tsirkin"<mst@xxxxxxxxxx>; "Pawel Osciak"<pawel@xxxxxxxxxx>; "Kyungmin Park"<kyungmin.park@xxxxxxxxxxx>; "Michael Chan"<michael.chan@xxxxxxxxxxxx>; "Benjamin Herrenschmidt"<benh@xxxxxxxxxxxxxxxxxxx>; "Ivan Mikhaylov"<ivan@xxxxxxxxxx>; "Tariq Toukan"<tariqt@xxxxxxxxxxxx>; "Andy Gross"<agross@xxxxxxxxxxxxxx>; "Mark A . Greer"<mgreer@xxxxxxxxxxxxxxx>; "Robert Baldyga"<r.baldyga@xxxxxxxxxxxxx>;
Subject:  Re: [PATCH V9 1/4] dma-mapping: Rework dma_get_cache_alignment()

Hi Huacai,

On 2017-10-23 09:12, Huacai Chen wrote:
Make dma_get_cache_alignment() to accept a 'dev' argument. As a result,
it can return different alignments due to different devices' I/O cache
coherency.

Currently, ARM/ARM64 and MIPS support coherent & noncoherent devices
co-exist. This may be extended in the future, so add a new function
pointer (i.e, get_cache_alignment) in 'struct dma_map_ops' as a generic
solution.

Cc: stable@xxxxxxxxxxxxxxx
I don't think this change should go to stable.

Cc: Michael S. Tsirkin <mst@xxxxxxxxxx>
Cc: Pawel Osciak <pawel@xxxxxxxxxx>
Cc: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
Cc: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
Cc: Michael Chan <michael.chan@xxxxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Ivan Mikhaylov <ivan@xxxxxxxxxx>
Cc: Tariq Toukan <tariqt@xxxxxxxxxxxx>
Cc: Andy Gross <agross@xxxxxxxxxxxxxx>
Cc: Mark A. Greer <mgreer@xxxxxxxxxxxxxxx>
Cc: Robert Baldyga <r.baldyga@xxxxxxxxxxxxx>
Cc: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
Signed-off-by: Huacai Chen <chenhc@xxxxxxxxxx>
---
   drivers/infiniband/hw/mthca/mthca_main.c       |   2 +-
   drivers/media/v4l2-core/videobuf2-dma-contig.c |   2 +-
   drivers/net/ethernet/broadcom/b44.c            |   8 +-
   drivers/net/ethernet/ibm/emac/core.c           |  32 +++--
   drivers/net/ethernet/ibm/emac/core.h           |  14 +-
   drivers/net/ethernet/mellanox/mlx4/main.c      |   2 +-
   drivers/spi/spi-qup.c                          |   4 +-
   drivers/tty/serial/mpsc.c                      | 179 +++++++++++++------------
   drivers/tty/serial/samsung.c                   |  14 +-
   include/linux/dma-mapping.h                    |  17 ++-
For videobuf2-dma-contig, serial/samsung and dma-mapping.h:

Acked-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>


   10 files changed, 150 insertions(+), 124 deletions(-)

diff --git a/drivers/infiniband/hw/mthca/mthca_main.c b/drivers/infiniband/hw/mthca/mthca_main.c
index e36a9bc..078fe8d 100644
--- a/drivers/infiniband/hw/mthca/mthca_main.c
+++ b/drivers/infiniband/hw/mthca/mthca_main.c
@@ -416,7 +416,7 @@ static int mthca_init_icm(struct mthca_dev *mdev,
/* CPU writes to non-reserved MTTs, while HCA might DMA to reserved mtts */
   	mdev->limits.reserved_mtts = ALIGN(mdev->limits.reserved_mtts * mdev->limits.mtt_seg_size,
-					   dma_get_cache_alignment()) / mdev->limits.mtt_seg_size;
+					   dma_get_cache_alignment(&mdev->pdev->dev)) / mdev->limits.mtt_seg_size;
mdev->mr_table.mtt_table = mthca_alloc_icm_table(mdev, init_hca->mtt_base,
   							 mdev->limits.mtt_seg_size,
diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c
index 9f389f3..1f6a9b7 100644
--- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
@@ -484,7 +484,7 @@ static void *vb2_dc_get_userptr(struct device *dev, unsigned long vaddr,
   	int ret = 0;
   	struct sg_table *sgt;
   	unsigned long contig_size;
-	unsigned long dma_align = dma_get_cache_alignment();
+	unsigned long dma_align = dma_get_cache_alignment(dev);
/* Only cache aligned DMA transfers are reliable */
   	if (!IS_ALIGNED(vaddr | size, dma_align)) {
diff --git a/drivers/net/ethernet/broadcom/b44.c b/drivers/net/ethernet/broadcom/b44.c
index a1125d1..2f6ffe5 100644
--- a/drivers/net/ethernet/broadcom/b44.c
+++ b/drivers/net/ethernet/broadcom/b44.c
@@ -2344,6 +2344,10 @@ static int b44_init_one(struct ssb_device *sdev,
   	struct net_device *dev;
   	struct b44 *bp;
   	int err;
+	unsigned int dma_desc_align_size = dma_get_cache_alignment(sdev->dma_dev);
+
+	/* Setup paramaters for syncing RX/TX DMA descriptors */
+	dma_desc_sync_size = max_t(unsigned int, dma_desc_align_size, sizeof(struct dma_desc));
instance++; @@ -2587,12 +2591,8 @@ static inline void b44_pci_exit(void) static int __init b44_init(void)
   {
-	unsigned int dma_desc_align_size = dma_get_cache_alignment();
   	int err;
- /* Setup paramaters for syncing RX/TX DMA descriptors */
-	dma_desc_sync_size = max_t(unsigned int, dma_desc_align_size, sizeof(struct dma_desc));
-
   	err = b44_pci_init();
   	if (err)
   		return err;
diff --git a/drivers/net/ethernet/ibm/emac/core.c b/drivers/net/ethernet/ibm/emac/core.c
index 7feff24..8dcebb2 100644
--- a/drivers/net/ethernet/ibm/emac/core.c
+++ b/drivers/net/ethernet/ibm/emac/core.c
@@ -1030,8 +1030,9 @@ static int emac_set_mac_address(struct net_device *ndev, void *sa)
static int emac_resize_rx_ring(struct emac_instance *dev, int new_mtu)
   {
-	int rx_sync_size = emac_rx_sync_size(new_mtu);
-	int rx_skb_size = emac_rx_skb_size(new_mtu);
+	struct device *dma_dev = &dev->ofdev->dev;
+	int rx_skb_size = emac_rx_skb_size(dma_dev, new_mtu);
+	int rx_sync_size = emac_rx_sync_size(dma_dev, new_mtu);
   	int i, ret = 0;
   	int mr1_jumbo_bit_change = 0;
@@ -1074,7 +1075,7 @@ static int emac_resize_rx_ring(struct emac_instance *dev, int new_mtu)
   		BUG_ON(!dev->rx_skb[i]);
   		dev_kfree_skb(dev->rx_skb[i]);
- skb_reserve(skb, EMAC_RX_SKB_HEADROOM + 2);
+		skb_reserve(skb, EMAC_RX_SKB_HEADROOM(dma_dev) + 2);
   		dev->rx_desc[i].data_ptr =
   		    dma_map_single(&dev->ofdev->dev, skb->data - 2, rx_sync_size,
   				   DMA_FROM_DEVICE) + 2;
@@ -1115,20 +1116,21 @@ static int emac_resize_rx_ring(struct emac_instance *dev, int new_mtu)
   static int emac_change_mtu(struct net_device *ndev, int new_mtu)
   {
   	struct emac_instance *dev = netdev_priv(ndev);
+	struct device *dma_dev = &dev->ofdev->dev;
   	int ret = 0;
DBG(dev, "change_mtu(%d)" NL, new_mtu); if (netif_running(ndev)) {
   		/* Check if we really need to reinitialize RX ring */
-		if (emac_rx_skb_size(ndev->mtu) != emac_rx_skb_size(new_mtu))
+		if (emac_rx_skb_size(dma_dev, ndev->mtu) != emac_rx_skb_size(dma_dev, new_mtu))
   			ret = emac_resize_rx_ring(dev, new_mtu);
   	}
if (!ret) {
   		ndev->mtu = new_mtu;
-		dev->rx_skb_size = emac_rx_skb_size(new_mtu);
-		dev->rx_sync_size = emac_rx_sync_size(new_mtu);
+		dev->rx_skb_size = emac_rx_skb_size(dma_dev, new_mtu);
+		dev->rx_sync_size = emac_rx_sync_size(dma_dev, new_mtu);
   	}
return ret;
@@ -1171,6 +1173,7 @@ static void emac_clean_rx_ring(struct emac_instance *dev)
   static inline int emac_alloc_rx_skb(struct emac_instance *dev, int slot,
   				    gfp_t flags)
   {
+	struct device *dma_dev = &dev->ofdev->dev;
   	struct sk_buff *skb = alloc_skb(dev->rx_skb_size, flags);
   	if (unlikely(!skb))
   		return -ENOMEM;
@@ -1178,7 +1181,7 @@ static inline int emac_alloc_rx_skb(struct emac_instance *dev, int slot,
   	dev->rx_skb[slot] = skb;
   	dev->rx_desc[slot].data_len = 0;
- skb_reserve(skb, EMAC_RX_SKB_HEADROOM + 2);
+	skb_reserve(skb, EMAC_RX_SKB_HEADROOM(dma_dev) + 2);
   	dev->rx_desc[slot].data_ptr =
   	    dma_map_single(&dev->ofdev->dev, skb->data - 2, dev->rx_sync_size,
   			   DMA_FROM_DEVICE) + 2;
@@ -1649,12 +1652,13 @@ static inline void emac_recycle_rx_skb(struct emac_instance *dev, int slot,
   				       int len)
   {
   	struct sk_buff *skb = dev->rx_skb[slot];
+	struct device *dma_dev = &dev->ofdev->dev;
DBG2(dev, "recycle %d %d" NL, slot, len); if (len)
-		dma_map_single(&dev->ofdev->dev, skb->data - 2,
-			       EMAC_DMA_ALIGN(len + 2), DMA_FROM_DEVICE);
+		dma_map_single(dma_dev, skb->data - 2,
+			       EMAC_DMA_ALIGN(dma_dev, len + 2), DMA_FROM_DEVICE);
dev->rx_desc[slot].data_len = 0;
   	wmb();
@@ -1727,6 +1731,7 @@ static int emac_poll_rx(void *param, int budget)
   {
   	struct emac_instance *dev = param;
   	int slot = dev->rx_slot, received = 0;
+	struct device *dma_dev = &dev->ofdev->dev;
DBG2(dev, "poll_rx(%d)" NL, budget); @@ -1763,11 +1768,11 @@ static int emac_poll_rx(void *param, int budget) if (len && len < EMAC_RX_COPY_THRESH) {
   			struct sk_buff *copy_skb =
-			    alloc_skb(len + EMAC_RX_SKB_HEADROOM + 2, GFP_ATOMIC);
+			    alloc_skb(len + EMAC_RX_SKB_HEADROOM(dma_dev) + 2, GFP_ATOMIC);
   			if (unlikely(!copy_skb))
   				goto oom;
- skb_reserve(copy_skb, EMAC_RX_SKB_HEADROOM + 2);
+			skb_reserve(copy_skb, EMAC_RX_SKB_HEADROOM(dma_dev) + 2);
   			memcpy(copy_skb->data - 2, skb->data - 2, len + 2);
   			emac_recycle_rx_skb(dev, slot, len);
   			skb = copy_skb;
@@ -2998,6 +3003,7 @@ static int emac_probe(struct platform_device *ofdev)
   	struct emac_instance *dev;
   	struct device_node *np = ofdev->dev.of_node;
   	struct device_node **blist = NULL;
+	struct device *dma_dev = &ofdev->dev;
   	int err, i;
/* Skip unused/unwired EMACS. We leave the check for an unused
@@ -3077,8 +3083,8 @@ static int emac_probe(struct platform_device *ofdev)
   		       np, dev->mal_dev->dev.of_node);
   		goto err_rel_deps;
   	}
-	dev->rx_skb_size = emac_rx_skb_size(ndev->mtu);
-	dev->rx_sync_size = emac_rx_sync_size(ndev->mtu);
+	dev->rx_skb_size = emac_rx_skb_size(dma_dev, ndev->mtu);
+	dev->rx_sync_size = emac_rx_sync_size(dma_dev, ndev->mtu);
/* Get pointers to BD rings */
   	dev->tx_desc =
diff --git a/drivers/net/ethernet/ibm/emac/core.h b/drivers/net/ethernet/ibm/emac/core.h
index 369de2c..8107c32 100644
--- a/drivers/net/ethernet/ibm/emac/core.h
+++ b/drivers/net/ethernet/ibm/emac/core.h
@@ -68,22 +68,22 @@ static inline int emac_rx_size(int mtu)
   		return mal_rx_size(ETH_DATA_LEN + EMAC_MTU_OVERHEAD);
   }
-#define EMAC_DMA_ALIGN(x) ALIGN((x), dma_get_cache_alignment())
+#define EMAC_DMA_ALIGN(d, x)		ALIGN((x), dma_get_cache_alignment(d))
-#define EMAC_RX_SKB_HEADROOM \
-	EMAC_DMA_ALIGN(CONFIG_IBM_EMAC_RX_SKB_HEADROOM)
+#define EMAC_RX_SKB_HEADROOM(d)		\
+	EMAC_DMA_ALIGN(d, CONFIG_IBM_EMAC_RX_SKB_HEADROOM)
/* Size of RX skb for the given MTU */
-static inline int emac_rx_skb_size(int mtu)
+static inline int emac_rx_skb_size(struct device *dev, int mtu)
   {
   	int size = max(mtu + EMAC_MTU_OVERHEAD, emac_rx_size(mtu));
-	return EMAC_DMA_ALIGN(size + 2) + EMAC_RX_SKB_HEADROOM;
+	return EMAC_DMA_ALIGN(dev, size + 2) + EMAC_RX_SKB_HEADROOM;
   }
/* RX DMA sync size */
-static inline int emac_rx_sync_size(int mtu)
+static inline int emac_rx_sync_size(struct device *dev, int mtu)
   {
-	return EMAC_DMA_ALIGN(emac_rx_size(mtu) + 2);
+	return EMAC_DMA_ALIGN(dev, emac_rx_size(mtu) + 2);
   }
/* Driver statistcs is split into two parts to make it more cache friendly:
diff --git a/drivers/net/ethernet/mellanox/mlx4/main.c b/drivers/net/ethernet/mellanox/mlx4/main.c
index e61c99e..bc146dd 100644
--- a/drivers/net/ethernet/mellanox/mlx4/main.c
+++ b/drivers/net/ethernet/mellanox/mlx4/main.c
@@ -1660,7 +1660,7 @@ static int mlx4_init_icm(struct mlx4_dev *dev, struct mlx4_dev_cap *dev_cap,
   	 */
   	dev->caps.reserved_mtts =
   		ALIGN(dev->caps.reserved_mtts * dev->caps.mtt_entry_sz,
-		      dma_get_cache_alignment()) / dev->caps.mtt_entry_sz;
+		      dma_get_cache_alignment(&dev->persist->pdev->dev)) / dev->caps.mtt_entry_sz;
err = mlx4_init_icm_table(dev, &priv->mr_table.mtt_table,
   				  init_hca->mtt_base,
diff --git a/drivers/spi/spi-qup.c b/drivers/spi/spi-qup.c
index 974a8ce..e6da66e 100644
--- a/drivers/spi/spi-qup.c
+++ b/drivers/spi/spi-qup.c
@@ -862,7 +862,7 @@ static bool spi_qup_can_dma(struct spi_master *master, struct spi_device *spi,
   			    struct spi_transfer *xfer)
   {
   	struct spi_qup *qup = spi_master_get_devdata(master);
-	size_t dma_align = dma_get_cache_alignment();
+	size_t dma_align = dma_get_cache_alignment(qup->dev);
   	int n_words;
if (xfer->rx_buf) {
@@ -1038,7 +1038,7 @@ static int spi_qup_probe(struct platform_device *pdev)
   	master->transfer_one = spi_qup_transfer_one;
   	master->dev.of_node = pdev->dev.of_node;
   	master->auto_runtime_pm = true;
-	master->dma_alignment = dma_get_cache_alignment();
+	master->dma_alignment = dma_get_cache_alignment(dev);
   	master->max_dma_len = SPI_MAX_XFER;
platform_set_drvdata(pdev, master);
diff --git a/drivers/tty/serial/mpsc.c b/drivers/tty/serial/mpsc.c
index 67ffecc..8b5d0de 100644
--- a/drivers/tty/serial/mpsc.c
+++ b/drivers/tty/serial/mpsc.c
@@ -81,19 +81,19 @@
    * Number of Tx & Rx descriptors must be powers of 2.
    */
   #define	MPSC_RXR_ENTRIES	32
-#define	MPSC_RXRE_SIZE		dma_get_cache_alignment()
-#define	MPSC_RXR_SIZE		(MPSC_RXR_ENTRIES * MPSC_RXRE_SIZE)
-#define	MPSC_RXBE_SIZE		dma_get_cache_alignment()
-#define	MPSC_RXB_SIZE		(MPSC_RXR_ENTRIES * MPSC_RXBE_SIZE)
+#define	MPSC_RXRE_SIZE(d)	dma_get_cache_alignment(d)
+#define	MPSC_RXR_SIZE(d)	(MPSC_RXR_ENTRIES * MPSC_RXRE_SIZE(d))
+#define	MPSC_RXBE_SIZE(d)	dma_get_cache_alignment(d)
+#define	MPSC_RXB_SIZE(d)	(MPSC_RXR_ENTRIES * MPSC_RXBE_SIZE(d))
#define MPSC_TXR_ENTRIES 32
-#define	MPSC_TXRE_SIZE		dma_get_cache_alignment()
-#define	MPSC_TXR_SIZE		(MPSC_TXR_ENTRIES * MPSC_TXRE_SIZE)
-#define	MPSC_TXBE_SIZE		dma_get_cache_alignment()
-#define	MPSC_TXB_SIZE		(MPSC_TXR_ENTRIES * MPSC_TXBE_SIZE)
+#define	MPSC_TXRE_SIZE(d)	dma_get_cache_alignment(d)
+#define	MPSC_TXR_SIZE(d)	(MPSC_TXR_ENTRIES * MPSC_TXRE_SIZE(d))
+#define	MPSC_TXBE_SIZE(d)	dma_get_cache_alignment(d)
+#define	MPSC_TXB_SIZE(d)	(MPSC_TXR_ENTRIES * MPSC_TXBE_SIZE(d))
-#define MPSC_DMA_ALLOC_SIZE (MPSC_RXR_SIZE + MPSC_RXB_SIZE + MPSC_TXR_SIZE \
-		+ MPSC_TXB_SIZE + dma_get_cache_alignment() /* for alignment */)
+#define	MPSC_DMA_ALLOC_SIZE(d)	(MPSC_RXR_SIZE(d) + MPSC_RXB_SIZE(d) + MPSC_TXR_SIZE(d) \
+		+ MPSC_TXB_SIZE(d) + dma_get_cache_alignment(d) /* for alignment */)
/* Rx and Tx Ring entry descriptors -- assume entry size is <= cacheline size */
   struct mpsc_rx_desc {
@@ -520,22 +520,23 @@ static uint mpsc_sdma_tx_active(struct mpsc_port_info *pi)
   static void mpsc_sdma_start_tx(struct mpsc_port_info *pi)
   {
   	struct mpsc_tx_desc *txre, *txre_p;
+	struct device *dma_dev = pi->port.dev;
/* If tx isn't running & there's a desc ready to go, start it */
   	if (!mpsc_sdma_tx_active(pi)) {
   		txre = (struct mpsc_tx_desc *)(pi->txr
-				+ (pi->txr_tail * MPSC_TXRE_SIZE));
-		dma_cache_sync(pi->port.dev, (void *)txre, MPSC_TXRE_SIZE,
+				+ (pi->txr_tail * MPSC_TXRE_SIZE(dma_dev)));
+		dma_cache_sync(pi->port.dev, (void *)txre, MPSC_TXRE_SIZE(dma_dev),
   				DMA_FROM_DEVICE);
   #if defined(CONFIG_PPC32) && !defined(CONFIG_NOT_COHERENT_CACHE)
   		if (pi->cache_mgmt) /* GT642[46]0 Res #COMM-2 */
   			invalidate_dcache_range((ulong)txre,
-					(ulong)txre + MPSC_TXRE_SIZE);
+					(ulong)txre + MPSC_TXRE_SIZE(dma_dev));
   #endif
if (be32_to_cpu(txre->cmdstat) & SDMA_DESC_CMDSTAT_O) {
   			txre_p = (struct mpsc_tx_desc *)
-				(pi->txr_p + (pi->txr_tail * MPSC_TXRE_SIZE));
+				(pi->txr_p + (pi->txr_tail * MPSC_TXRE_SIZE(dma_dev)));
mpsc_sdma_set_tx_ring(pi, txre_p);
   			mpsc_sdma_cmd(pi, SDMA_SDCM_STD | SDMA_SDCM_TXD);
@@ -738,7 +739,7 @@ static void mpsc_init_hw(struct mpsc_port_info *pi)
mpsc_brg_init(pi, pi->brg_clk_src);
   	mpsc_brg_enable(pi);
-	mpsc_sdma_init(pi, dma_get_cache_alignment());	/* burst a cacheline */
+	mpsc_sdma_init(pi, dma_get_cache_alignment(pi->port.dev));	/* burst a cacheline */
   	mpsc_sdma_stop(pi);
   	mpsc_hw_init(pi);
   }
@@ -746,6 +747,7 @@ static void mpsc_init_hw(struct mpsc_port_info *pi)
   static int mpsc_alloc_ring_mem(struct mpsc_port_info *pi)
   {
   	int rc = 0;
+	struct device *dma_dev = pi->port.dev;
pr_debug("mpsc_alloc_ring_mem[%d]: Allocating ring mem\n",
   		pi->port.line);
@@ -755,7 +757,7 @@ static int mpsc_alloc_ring_mem(struct mpsc_port_info *pi)
   			printk(KERN_ERR "MPSC: Inadequate DMA support\n");
   			rc = -ENXIO;
   		} else if ((pi->dma_region = dma_alloc_attrs(pi->port.dev,
-						MPSC_DMA_ALLOC_SIZE,
+						MPSC_DMA_ALLOC_SIZE(dma_dev),
   						&pi->dma_region_p, GFP_KERNEL,
   						DMA_ATTR_NON_CONSISTENT))
   				== NULL) {
@@ -769,10 +771,12 @@ static int mpsc_alloc_ring_mem(struct mpsc_port_info *pi)
static void mpsc_free_ring_mem(struct mpsc_port_info *pi)
   {
+	struct device *dma_dev = pi->port.dev;
+
   	pr_debug("mpsc_free_ring_mem[%d]: Freeing ring mem\n", pi->port.line);
if (pi->dma_region) {
-		dma_free_attrs(pi->port.dev, MPSC_DMA_ALLOC_SIZE,
+		dma_free_attrs(pi->port.dev, MPSC_DMA_ALLOC_SIZE(dma_dev),
   				pi->dma_region, pi->dma_region_p,
   				DMA_ATTR_NON_CONSISTENT);
   		pi->dma_region = NULL;
@@ -784,6 +788,7 @@ static void mpsc_init_rings(struct mpsc_port_info *pi)
   {
   	struct mpsc_rx_desc *rxre;
   	struct mpsc_tx_desc *txre;
+	struct device *dma_dev = pi->port.dev;
   	dma_addr_t dp, dp_p;
   	u8 *bp, *bp_p;
   	int i;
@@ -792,14 +797,14 @@ static void mpsc_init_rings(struct mpsc_port_info *pi)
BUG_ON(pi->dma_region == NULL); - memset(pi->dma_region, 0, MPSC_DMA_ALLOC_SIZE);
+	memset(pi->dma_region, 0, MPSC_DMA_ALLOC_SIZE(dma_dev));
/*
   	 * Descriptors & buffers are multiples of cacheline size and must be
   	 * cacheline aligned.
   	 */
-	dp = ALIGN((u32)pi->dma_region, dma_get_cache_alignment());
-	dp_p = ALIGN((u32)pi->dma_region_p, dma_get_cache_alignment());
+	dp = ALIGN((u32)pi->dma_region, dma_get_cache_alignment(dma_dev));
+	dp_p = ALIGN((u32)pi->dma_region_p, dma_get_cache_alignment(dma_dev));
/*
   	 * Partition dma region into rx ring descriptor, rx buffers,
@@ -807,20 +812,20 @@ static void mpsc_init_rings(struct mpsc_port_info *pi)
   	 */
   	pi->rxr = dp;
   	pi->rxr_p = dp_p;
-	dp += MPSC_RXR_SIZE;
-	dp_p += MPSC_RXR_SIZE;
+	dp += MPSC_RXR_SIZE(dma_dev);
+	dp_p += MPSC_RXR_SIZE(dma_dev);
pi->rxb = (u8 *)dp;
   	pi->rxb_p = (u8 *)dp_p;
-	dp += MPSC_RXB_SIZE;
-	dp_p += MPSC_RXB_SIZE;
+	dp += MPSC_RXB_SIZE(dma_dev);
+	dp_p += MPSC_RXB_SIZE(dma_dev);
pi->rxr_posn = 0; pi->txr = dp;
   	pi->txr_p = dp_p;
-	dp += MPSC_TXR_SIZE;
-	dp_p += MPSC_TXR_SIZE;
+	dp += MPSC_TXR_SIZE(dma_dev);
+	dp_p += MPSC_TXR_SIZE(dma_dev);
pi->txb = (u8 *)dp;
   	pi->txb_p = (u8 *)dp_p;
@@ -837,18 +842,18 @@ static void mpsc_init_rings(struct mpsc_port_info *pi)
   	for (i = 0; i < MPSC_RXR_ENTRIES; i++) {
   		rxre = (struct mpsc_rx_desc *)dp;
- rxre->bufsize = cpu_to_be16(MPSC_RXBE_SIZE);
+		rxre->bufsize = cpu_to_be16(MPSC_RXBE_SIZE(dma_dev));
   		rxre->bytecnt = cpu_to_be16(0);
   		rxre->cmdstat = cpu_to_be32(SDMA_DESC_CMDSTAT_O
   				| SDMA_DESC_CMDSTAT_EI | SDMA_DESC_CMDSTAT_F
   				| SDMA_DESC_CMDSTAT_L);
-		rxre->link = cpu_to_be32(dp_p + MPSC_RXRE_SIZE);
+		rxre->link = cpu_to_be32(dp_p + MPSC_RXRE_SIZE(dma_dev));
   		rxre->buf_ptr = cpu_to_be32(bp_p);
- dp += MPSC_RXRE_SIZE;
-		dp_p += MPSC_RXRE_SIZE;
-		bp += MPSC_RXBE_SIZE;
-		bp_p += MPSC_RXBE_SIZE;
+		dp += MPSC_RXRE_SIZE(dma_dev);
+		dp_p += MPSC_RXRE_SIZE(dma_dev);
+		bp += MPSC_RXBE_SIZE(dma_dev);
+		bp_p += MPSC_RXBE_SIZE(dma_dev);
   	}
   	rxre->link = cpu_to_be32(pi->rxr_p);	/* Wrap last back to first */
@@ -861,23 +866,23 @@ static void mpsc_init_rings(struct mpsc_port_info *pi)
   	for (i = 0; i < MPSC_TXR_ENTRIES; i++) {
   		txre = (struct mpsc_tx_desc *)dp;
- txre->link = cpu_to_be32(dp_p + MPSC_TXRE_SIZE);
+		txre->link = cpu_to_be32(dp_p + MPSC_TXRE_SIZE(dma_dev));
   		txre->buf_ptr = cpu_to_be32(bp_p);
- dp += MPSC_TXRE_SIZE;
-		dp_p += MPSC_TXRE_SIZE;
-		bp += MPSC_TXBE_SIZE;
-		bp_p += MPSC_TXBE_SIZE;
+		dp += MPSC_TXRE_SIZE(dma_dev);
+		dp_p += MPSC_TXRE_SIZE(dma_dev);
+		bp += MPSC_TXBE_SIZE(dma_dev);
+		bp_p += MPSC_TXBE_SIZE(dma_dev);
   	}
   	txre->link = cpu_to_be32(pi->txr_p);	/* Wrap last back to first */
dma_cache_sync(pi->port.dev, (void *)pi->dma_region,
-			MPSC_DMA_ALLOC_SIZE, DMA_BIDIRECTIONAL);
+			MPSC_DMA_ALLOC_SIZE(dma_dev), DMA_BIDIRECTIONAL);
   #if defined(CONFIG_PPC32) && !defined(CONFIG_NOT_COHERENT_CACHE)
   		if (pi->cache_mgmt) /* GT642[46]0 Res #COMM-2 */
   			flush_dcache_range((ulong)pi->dma_region,
   					(ulong)pi->dma_region
-					+ MPSC_DMA_ALLOC_SIZE);
+					+ MPSC_DMA_ALLOC_SIZE(dma_dev));
   #endif
return;
@@ -936,6 +941,7 @@ static int serial_polled;
   static int mpsc_rx_intr(struct mpsc_port_info *pi, unsigned long *flags)
   {
   	struct mpsc_rx_desc *rxre;
+	struct device *dma_dev = pi->port.dev;
   	struct tty_port *port = &pi->port.state->port;
   	u32	cmdstat, bytes_in, i;
   	int	rc = 0;
@@ -944,14 +950,14 @@ static int mpsc_rx_intr(struct mpsc_port_info *pi, unsigned long *flags)
pr_debug("mpsc_rx_intr[%d]: Handling Rx intr\n", pi->port.line); - rxre = (struct mpsc_rx_desc *)(pi->rxr + (pi->rxr_posn*MPSC_RXRE_SIZE));
+	rxre = (struct mpsc_rx_desc *)(pi->rxr + (pi->rxr_posn*MPSC_RXRE_SIZE(dma_dev)));
- dma_cache_sync(pi->port.dev, (void *)rxre, MPSC_RXRE_SIZE,
+	dma_cache_sync(pi->port.dev, (void *)rxre, MPSC_RXRE_SIZE(dma_dev),
   			DMA_FROM_DEVICE);
   #if defined(CONFIG_PPC32) && !defined(CONFIG_NOT_COHERENT_CACHE)
   	if (pi->cache_mgmt) /* GT642[46]0 Res #COMM-2 */
   		invalidate_dcache_range((ulong)rxre,
-				(ulong)rxre + MPSC_RXRE_SIZE);
+				(ulong)rxre + MPSC_RXRE_SIZE(dma_dev));
   #endif
/*
@@ -979,13 +985,13 @@ static int mpsc_rx_intr(struct mpsc_port_info *pi, unsigned long *flags)
   			 */
   		}
- bp = pi->rxb + (pi->rxr_posn * MPSC_RXBE_SIZE);
-		dma_cache_sync(pi->port.dev, (void *)bp, MPSC_RXBE_SIZE,
+		bp = pi->rxb + (pi->rxr_posn * MPSC_RXBE_SIZE(dma_dev));
+		dma_cache_sync(pi->port.dev, (void *)bp, MPSC_RXBE_SIZE(dma_dev),
   				DMA_FROM_DEVICE);
   #if defined(CONFIG_PPC32) && !defined(CONFIG_NOT_COHERENT_CACHE)
   		if (pi->cache_mgmt) /* GT642[46]0 Res #COMM-2 */
   			invalidate_dcache_range((ulong)bp,
-					(ulong)bp + MPSC_RXBE_SIZE);
+					(ulong)bp + MPSC_RXBE_SIZE(dma_dev));
   #endif
/*
@@ -1056,24 +1062,24 @@ static int mpsc_rx_intr(struct mpsc_port_info *pi, unsigned long *flags)
   				| SDMA_DESC_CMDSTAT_EI | SDMA_DESC_CMDSTAT_F
   				| SDMA_DESC_CMDSTAT_L);
   		wmb();
-		dma_cache_sync(pi->port.dev, (void *)rxre, MPSC_RXRE_SIZE,
+		dma_cache_sync(pi->port.dev, (void *)rxre, MPSC_RXRE_SIZE(dma_dev),
   				DMA_BIDIRECTIONAL);
   #if defined(CONFIG_PPC32) && !defined(CONFIG_NOT_COHERENT_CACHE)
   		if (pi->cache_mgmt) /* GT642[46]0 Res #COMM-2 */
   			flush_dcache_range((ulong)rxre,
-					(ulong)rxre + MPSC_RXRE_SIZE);
+					(ulong)rxre + MPSC_RXRE_SIZE(dma_dev));
   #endif
/* Advance to next descriptor */
   		pi->rxr_posn = (pi->rxr_posn + 1) & (MPSC_RXR_ENTRIES - 1);
   		rxre = (struct mpsc_rx_desc *)
-			(pi->rxr + (pi->rxr_posn * MPSC_RXRE_SIZE));
-		dma_cache_sync(pi->port.dev, (void *)rxre, MPSC_RXRE_SIZE,
+			(pi->rxr + (pi->rxr_posn * MPSC_RXRE_SIZE(dma_dev)));
+		dma_cache_sync(pi->port.dev, (void *)rxre, MPSC_RXRE_SIZE(dma_dev),
   				DMA_FROM_DEVICE);
   #if defined(CONFIG_PPC32) && !defined(CONFIG_NOT_COHERENT_CACHE)
   		if (pi->cache_mgmt) /* GT642[46]0 Res #COMM-2 */
   			invalidate_dcache_range((ulong)rxre,
-					(ulong)rxre + MPSC_RXRE_SIZE);
+					(ulong)rxre + MPSC_RXRE_SIZE(dma_dev));
   #endif
   		rc = 1;
   	}
@@ -1091,9 +1097,10 @@ static int mpsc_rx_intr(struct mpsc_port_info *pi, unsigned long *flags)
   static void mpsc_setup_tx_desc(struct mpsc_port_info *pi, u32 count, u32 intr)
   {
   	struct mpsc_tx_desc *txre;
+	struct device *dma_dev = pi->port.dev;
txre = (struct mpsc_tx_desc *)(pi->txr
-			+ (pi->txr_head * MPSC_TXRE_SIZE));
+			+ (pi->txr_head * MPSC_TXRE_SIZE(dma_dev)));
txre->bytecnt = cpu_to_be16(count);
   	txre->shadow = txre->bytecnt;
@@ -1102,17 +1109,18 @@ static void mpsc_setup_tx_desc(struct mpsc_port_info *pi, u32 count, u32 intr)
   			| SDMA_DESC_CMDSTAT_L
   			| ((intr) ? SDMA_DESC_CMDSTAT_EI : 0));
   	wmb();
-	dma_cache_sync(pi->port.dev, (void *)txre, MPSC_TXRE_SIZE,
+	dma_cache_sync(pi->port.dev, (void *)txre, MPSC_TXRE_SIZE(dma_dev),
   			DMA_BIDIRECTIONAL);
   #if defined(CONFIG_PPC32) && !defined(CONFIG_NOT_COHERENT_CACHE)
   	if (pi->cache_mgmt) /* GT642[46]0 Res #COMM-2 */
   		flush_dcache_range((ulong)txre,
-				(ulong)txre + MPSC_TXRE_SIZE);
+				(ulong)txre + MPSC_TXRE_SIZE(dma_dev));
   #endif
   }
static void mpsc_copy_tx_data(struct mpsc_port_info *pi)
   {
+	struct device *dma_dev = pi->port.dev;
   	struct circ_buf *xmit = &pi->port.state->xmit;
   	u8 *bp;
   	u32 i;
@@ -1129,17 +1137,17 @@ static void mpsc_copy_tx_data(struct mpsc_port_info *pi)
   			 * CHR_1.  Instead, just put it in-band with
   			 * all the other Tx data.
   			 */
-			bp = pi->txb + (pi->txr_head * MPSC_TXBE_SIZE);
+			bp = pi->txb + (pi->txr_head * MPSC_TXBE_SIZE(dma_dev));
   			*bp = pi->port.x_char;
   			pi->port.x_char = 0;
   			i = 1;
   		} else if (!uart_circ_empty(xmit)
   				&& !uart_tx_stopped(&pi->port)) {
-			i = min((u32)MPSC_TXBE_SIZE,
+			i = min((u32)MPSC_TXBE_SIZE(dma_dev),
   				(u32)uart_circ_chars_pending(xmit));
   			i = min(i, (u32)CIRC_CNT_TO_END(xmit->head, xmit->tail,
   				UART_XMIT_SIZE));
-			bp = pi->txb + (pi->txr_head * MPSC_TXBE_SIZE);
+			bp = pi->txb + (pi->txr_head * MPSC_TXBE_SIZE(dma_dev));
   			memcpy(bp, &xmit->buf[xmit->tail], i);
   			xmit->tail = (xmit->tail + i) & (UART_XMIT_SIZE - 1);
@@ -1149,12 +1157,12 @@ static void mpsc_copy_tx_data(struct mpsc_port_info *pi)
   			return;
   		}
- dma_cache_sync(pi->port.dev, (void *)bp, MPSC_TXBE_SIZE,
+		dma_cache_sync(pi->port.dev, (void *)bp, MPSC_TXBE_SIZE(dma_dev),
   				DMA_BIDIRECTIONAL);
   #if defined(CONFIG_PPC32) && !defined(CONFIG_NOT_COHERENT_CACHE)
   		if (pi->cache_mgmt) /* GT642[46]0 Res #COMM-2 */
   			flush_dcache_range((ulong)bp,
-					(ulong)bp + MPSC_TXBE_SIZE);
+					(ulong)bp + MPSC_TXBE_SIZE(dma_dev));
   #endif
   		mpsc_setup_tx_desc(pi, i, 1);
@@ -1166,6 +1174,7 @@ static void mpsc_copy_tx_data(struct mpsc_port_info *pi)
   static int mpsc_tx_intr(struct mpsc_port_info *pi)
   {
   	struct mpsc_tx_desc *txre;
+	struct device *dma_dev = pi->port.dev;
   	int rc = 0;
   	unsigned long iflags;
@@ -1173,14 +1182,14 @@ static int mpsc_tx_intr(struct mpsc_port_info *pi) if (!mpsc_sdma_tx_active(pi)) {
   		txre = (struct mpsc_tx_desc *)(pi->txr
-				+ (pi->txr_tail * MPSC_TXRE_SIZE));
+				+ (pi->txr_tail * MPSC_TXRE_SIZE(dma_dev)));
- dma_cache_sync(pi->port.dev, (void *)txre, MPSC_TXRE_SIZE,
+		dma_cache_sync(pi->port.dev, (void *)txre, MPSC_TXRE_SIZE(dma_dev),
   				DMA_FROM_DEVICE);
   #if defined(CONFIG_PPC32) && !defined(CONFIG_NOT_COHERENT_CACHE)
   		if (pi->cache_mgmt) /* GT642[46]0 Res #COMM-2 */
   			invalidate_dcache_range((ulong)txre,
-					(ulong)txre + MPSC_TXRE_SIZE);
+					(ulong)txre + MPSC_TXRE_SIZE(dma_dev));
   #endif
while (!(be32_to_cpu(txre->cmdstat) & SDMA_DESC_CMDSTAT_O)) {
@@ -1193,13 +1202,13 @@ static int mpsc_tx_intr(struct mpsc_port_info *pi)
   				break;
txre = (struct mpsc_tx_desc *)(pi->txr
-					+ (pi->txr_tail * MPSC_TXRE_SIZE));
+					+ (pi->txr_tail * MPSC_TXRE_SIZE(dma_dev)));
   			dma_cache_sync(pi->port.dev, (void *)txre,
-					MPSC_TXRE_SIZE, DMA_FROM_DEVICE);
+					MPSC_TXRE_SIZE(dma_dev), DMA_FROM_DEVICE);
   #if defined(CONFIG_PPC32) && !defined(CONFIG_NOT_COHERENT_CACHE)
   			if (pi->cache_mgmt) /* GT642[46]0 Res #COMM-2 */
   				invalidate_dcache_range((ulong)txre,
-						(ulong)txre + MPSC_TXRE_SIZE);
+						(ulong)txre + MPSC_TXRE_SIZE(dma_dev));
   #endif
   		}
@@ -1360,6 +1369,7 @@ static int mpsc_startup(struct uart_port *port)
   {
   	struct mpsc_port_info *pi =
   		container_of(port, struct mpsc_port_info, port);
+	struct device *dma_dev = pi->port.dev;
   	u32 flag = 0;
   	int rc;
@@ -1381,7 +1391,7 @@ static int mpsc_startup(struct uart_port *port) mpsc_sdma_intr_unmask(pi, 0xf);
   		mpsc_sdma_set_rx_ring(pi, (struct mpsc_rx_desc *)(pi->rxr_p
-					+ (pi->rxr_posn * MPSC_RXRE_SIZE)));
+					+ (pi->rxr_posn * MPSC_RXRE_SIZE(dma_dev))));
   	}
return rc;
@@ -1555,9 +1565,10 @@ static void mpsc_put_poll_char(struct uart_port *port,
static int mpsc_get_poll_char(struct uart_port *port)
   {
+	struct mpsc_rx_desc *rxre;
   	struct mpsc_port_info *pi =
   		container_of(port, struct mpsc_port_info, port);
-	struct mpsc_rx_desc *rxre;
+	struct device *dma_dev = pi->port.dev;
   	u32	cmdstat, bytes_in, i;
   	u8	*bp;
@@ -1575,13 +1586,13 @@ static int mpsc_get_poll_char(struct uart_port *port) while (poll_cnt == 0) {
   		rxre = (struct mpsc_rx_desc *)(pi->rxr +
-		       (pi->rxr_posn*MPSC_RXRE_SIZE));
+		       (pi->rxr_posn*MPSC_RXRE_SIZE(dma_dev)));
   		dma_cache_sync(pi->port.dev, (void *)rxre,
-			       MPSC_RXRE_SIZE, DMA_FROM_DEVICE);
+			       MPSC_RXRE_SIZE(dma_dev), DMA_FROM_DEVICE);
   #if defined(CONFIG_PPC32) && !defined(CONFIG_NOT_COHERENT_CACHE)
   		if (pi->cache_mgmt) /* GT642[46]0 Res #COMM-2 */
   			invalidate_dcache_range((ulong)rxre,
-			(ulong)rxre + MPSC_RXRE_SIZE);
+			(ulong)rxre + MPSC_RXRE_SIZE(dma_dev));
   #endif
   		/*
   		 * Loop through Rx descriptors handling ones that have
@@ -1591,13 +1602,13 @@ static int mpsc_get_poll_char(struct uart_port *port)
   		       !((cmdstat = be32_to_cpu(rxre->cmdstat)) &
   			 SDMA_DESC_CMDSTAT_O)){
   			bytes_in = be16_to_cpu(rxre->bytecnt);
-			bp = pi->rxb + (pi->rxr_posn * MPSC_RXBE_SIZE);
+			bp = pi->rxb + (pi->rxr_posn * MPSC_RXBE_SIZE(dma_dev));
   			dma_cache_sync(pi->port.dev, (void *) bp,
-				       MPSC_RXBE_SIZE, DMA_FROM_DEVICE);
+				       MPSC_RXBE_SIZE(dma_dev), DMA_FROM_DEVICE);
   #if defined(CONFIG_PPC32) && !defined(CONFIG_NOT_COHERENT_CACHE)
   			if (pi->cache_mgmt) /* GT642[46]0 Res #COMM-2 */
   				invalidate_dcache_range((ulong)bp,
-					(ulong)bp + MPSC_RXBE_SIZE);
+					(ulong)bp + MPSC_RXBE_SIZE(dma_dev));
   #endif
   			if ((unlikely(cmdstat & (SDMA_DESC_CMDSTAT_BR |
   			 SDMA_DESC_CMDSTAT_FR | SDMA_DESC_CMDSTAT_OR))) &&
@@ -1619,24 +1630,24 @@ static int mpsc_get_poll_char(struct uart_port *port)
   						    SDMA_DESC_CMDSTAT_L);
   			wmb();
   			dma_cache_sync(pi->port.dev, (void *)rxre,
-				       MPSC_RXRE_SIZE, DMA_BIDIRECTIONAL);
+				       MPSC_RXRE_SIZE(dma_dev), DMA_BIDIRECTIONAL);
   #if defined(CONFIG_PPC32) && !defined(CONFIG_NOT_COHERENT_CACHE)
   			if (pi->cache_mgmt) /* GT642[46]0 Res #COMM-2 */
   				flush_dcache_range((ulong)rxre,
-					   (ulong)rxre + MPSC_RXRE_SIZE);
+					   (ulong)rxre + MPSC_RXRE_SIZE(dma_dev));
   #endif
/* Advance to next descriptor */
   			pi->rxr_posn = (pi->rxr_posn + 1) &
   				(MPSC_RXR_ENTRIES - 1);
   			rxre = (struct mpsc_rx_desc *)(pi->rxr +
-				       (pi->rxr_posn * MPSC_RXRE_SIZE));
+				       (pi->rxr_posn * MPSC_RXRE_SIZE(dma_dev)));
   			dma_cache_sync(pi->port.dev, (void *)rxre,
-				       MPSC_RXRE_SIZE, DMA_FROM_DEVICE);
+				       MPSC_RXRE_SIZE(dma_dev), DMA_FROM_DEVICE);
   #if defined(CONFIG_PPC32) && !defined(CONFIG_NOT_COHERENT_CACHE)
   			if (pi->cache_mgmt) /* GT642[46]0 Res #COMM-2 */
   				invalidate_dcache_range((ulong)rxre,
-						(ulong)rxre + MPSC_RXRE_SIZE);
+						(ulong)rxre + MPSC_RXRE_SIZE(dma_dev));
   #endif
   		}
@@ -1706,6 +1717,7 @@ static const struct uart_ops mpsc_pops = {
   static void mpsc_console_write(struct console *co, const char *s, uint count)
   {
   	struct mpsc_port_info *pi = &mpsc_ports[co->index];
+	struct device *dma_dev = pi->port.dev;
   	u8 *bp, *dp, add_cr = 0;
   	int i;
   	unsigned long iflags;
@@ -1723,9 +1735,9 @@ static void mpsc_console_write(struct console *co, const char *s, uint count)
   		udelay(100);
while (count > 0) {
-		bp = dp = pi->txb + (pi->txr_head * MPSC_TXBE_SIZE);
+		bp = dp = pi->txb + (pi->txr_head * MPSC_TXBE_SIZE(dma_dev));
- for (i = 0; i < MPSC_TXBE_SIZE; i++) {
+		for (i = 0; i < MPSC_TXBE_SIZE(dma_dev); i++) {
   			if (count == 0)
   				break;
@@ -1744,12 +1756,12 @@ static void mpsc_console_write(struct console *co, const char *s, uint count)
   			count--;
   		}
- dma_cache_sync(pi->port.dev, (void *)bp, MPSC_TXBE_SIZE,
+		dma_cache_sync(pi->port.dev, (void *)bp, MPSC_TXBE_SIZE(dma_dev),
   				DMA_BIDIRECTIONAL);
   #if defined(CONFIG_PPC32) && !defined(CONFIG_NOT_COHERENT_CACHE)
   		if (pi->cache_mgmt) /* GT642[46]0 Res #COMM-2 */
   			flush_dcache_range((ulong)bp,
-					(ulong)bp + MPSC_TXBE_SIZE);
+					(ulong)bp + MPSC_TXBE_SIZE(dma_dev));
   #endif
   		mpsc_setup_tx_desc(pi, i, 0);
   		pi->txr_head = (pi->txr_head + 1) & (MPSC_TXR_ENTRIES - 1);
@@ -2024,7 +2036,8 @@ static void mpsc_drv_unmap_regs(struct mpsc_port_info *pi)
   static void mpsc_drv_get_platform_data(struct mpsc_port_info *pi,
   		struct platform_device *pd, int num)
   {
-	struct mpsc_pdata	*pdata;
+	struct mpsc_pdata *pdata;
+	struct device *dma_dev = pi->port.dev;
pdata = dev_get_platdata(&pd->dev); @@ -2032,7 +2045,7 @@ static void mpsc_drv_get_platform_data(struct mpsc_port_info *pi,
   	pi->port.iotype = UPIO_MEM;
   	pi->port.line = num;
   	pi->port.type = PORT_MPSC;
-	pi->port.fifosize = MPSC_TXBE_SIZE;
+	pi->port.fifosize = MPSC_TXBE_SIZE(dma_dev);
   	pi->port.membase = pi->mpsc_base;
   	pi->port.mapbase = (ulong)pi->mpsc_base;
   	pi->port.ops = &mpsc_pops;
diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c
index 8aca18c..9df918e5 100644
--- a/drivers/tty/serial/samsung.c
+++ b/drivers/tty/serial/samsung.c
@@ -241,7 +241,7 @@ static void enable_tx_dma(struct s3c24xx_uart_port *ourport)
   	/* Enable tx dma mode */
   	ucon = rd_regl(port, S3C2410_UCON);
   	ucon &= ~(S3C64XX_UCON_TXBURST_MASK | S3C64XX_UCON_TXMODE_MASK);
-	ucon |= (dma_get_cache_alignment() >= 16) ?
+	ucon |= (dma_get_cache_alignment(port->dev) >= 16) ?
   		S3C64XX_UCON_TXBURST_16 : S3C64XX_UCON_TXBURST_1;
   	ucon |= S3C64XX_UCON_TXMODE_DMA;
   	wr_regl(port,  S3C2410_UCON, ucon);
@@ -292,7 +292,7 @@ static int s3c24xx_serial_start_tx_dma(struct s3c24xx_uart_port *ourport,
   	if (ourport->tx_mode != S3C24XX_TX_DMA)
   		enable_tx_dma(ourport);
- dma->tx_size = count & ~(dma_get_cache_alignment() - 1);
+	dma->tx_size = count & ~(dma_get_cache_alignment(port->dev) - 1);
   	dma->tx_transfer_addr = dma->tx_addr + xmit->tail;
dma_sync_single_for_device(ourport->port.dev, dma->tx_transfer_addr,
@@ -332,7 +332,7 @@ static void s3c24xx_serial_start_next_tx(struct s3c24xx_uart_port *ourport)
if (!ourport->dma || !ourport->dma->tx_chan ||
   	    count < ourport->min_dma_size ||
-	    xmit->tail & (dma_get_cache_alignment() - 1))
+	    xmit->tail & (dma_get_cache_alignment(port->dev) - 1))
   		s3c24xx_serial_start_tx_pio(ourport);
   	else
   		s3c24xx_serial_start_tx_dma(ourport, count);
@@ -718,8 +718,8 @@ static irqreturn_t s3c24xx_serial_tx_chars(int irq, void *id)
if (ourport->dma && ourport->dma->tx_chan &&
   	    count >= ourport->min_dma_size) {
-		int align = dma_get_cache_alignment() -
-			(xmit->tail & (dma_get_cache_alignment() - 1));
+		int align = dma_get_cache_alignment(port->dev) -
+			(xmit->tail & (dma_get_cache_alignment(port->dev) - 1));
   		if (count-align >= ourport->min_dma_size) {
   			dma_count = count-align;
   			count = align;
@@ -870,7 +870,7 @@ static int s3c24xx_serial_request_dma(struct s3c24xx_uart_port *p)
   	dma->tx_conf.direction		= DMA_MEM_TO_DEV;
   	dma->tx_conf.dst_addr_width	= DMA_SLAVE_BUSWIDTH_1_BYTE;
   	dma->tx_conf.dst_addr		= p->port.mapbase + S3C2410_UTXH;
-	if (dma_get_cache_alignment() >= 16)
+	if (dma_get_cache_alignment(p->port.dev) >= 16)
   		dma->tx_conf.dst_maxburst = 16;
   	else
   		dma->tx_conf.dst_maxburst = 1;
@@ -1849,7 +1849,7 @@ static int s3c24xx_serial_probe(struct platform_device *pdev)
   	 * so find minimal transfer size suitable for DMA mode
   	 */
   	ourport->min_dma_size = max_t(int, ourport->port.fifosize,
-				    dma_get_cache_alignment());
+				    dma_get_cache_alignment(ourport->port.dev));
dbg("%s: initialising port %p...\n", __func__, ourport); diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 29ce981..1326023 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -131,6 +131,7 @@ struct dma_map_ops {
   #ifdef ARCH_HAS_DMA_GET_REQUIRED_MASK
   	u64 (*get_required_mask)(struct device *dev);
   #endif
+	int (*get_cache_alignment)(struct device *dev);
   	int is_phys;
   };
@@ -697,12 +698,18 @@ static inline void *dma_zalloc_coherent(struct device *dev, size_t size,
   }
#ifdef CONFIG_HAS_DMA
-static inline int dma_get_cache_alignment(void)
-{
-#ifdef ARCH_DMA_MINALIGN
-	return ARCH_DMA_MINALIGN;
+
+#ifndef ARCH_DMA_MINALIGN
+#define ARCH_DMA_MINALIGN 1
   #endif
-	return 1;
+
+static inline int dma_get_cache_alignment(struct device *dev)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+	if (dev && ops && ops->get_cache_alignment)
+		return ops->get_cache_alignment(dev);
+
+	return ARCH_DMA_MINALIGN; /* compatible behavior */
   }
   #endif
Best regards

Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland




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