tg3: Allow DMAs to cross cacheline boundaries

By default, the 5717 (and future chips) break up PCIe DMA packets across
cacheline boundaries.  This isn't necessary on x86.  This patch
selectively loosens the restriction.

Signed-off-by: Matt Carlson <mcarlson@broadcom.com>
Reviewed-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/tg3.c

@@ -7294,9 +7294,12 @@ static int tg3_reset_hw(struct tg3 *tp, int reset_phy)
 	if (err)
 		return err;
 
-	if (GET_ASIC_REV(tp->pci_chip_rev_id) != ASIC_REV_5784 &&
-	    GET_ASIC_REV(tp->pci_chip_rev_id) != ASIC_REV_5761 &&
-	    GET_ASIC_REV(tp->pci_chip_rev_id) != ASIC_REV_5717) {
+	if (GET_ASIC_REV(tp->pci_chip_rev_id) == ASIC_REV_5717) {
+		val = tr32(TG3PCI_DMA_RW_CTRL) &
+		      ~DMA_RWCTRL_DIS_CACHE_ALIGNMENT;
+		tw32(TG3PCI_DMA_RW_CTRL, val | tp->dma_rwctrl);
+	} else if (GET_ASIC_REV(tp->pci_chip_rev_id) != ASIC_REV_5784 &&
+		   GET_ASIC_REV(tp->pci_chip_rev_id) != ASIC_REV_5761) {
 		/* This value is determined during the probe time DMA
 		 * engine test, tg3_test_dma.
 		 */
@@ -13329,6 +13332,11 @@ static u32 __devinit tg3_calc_dma_bndry(struct tg3 *tp, u32 val)
 #endif
 #endif
 
+	if (GET_ASIC_REV(tp->pci_chip_rev_id) == ASIC_REV_5717) {
+		val = goal ? 0 : DMA_RWCTRL_DIS_CACHE_ALIGNMENT;
+		goto out;
+	}
+
 	if (!goal)
 		goto out;
 
@@ -13523,7 +13531,7 @@ static int __devinit tg3_test_dma(struct tg3 *tp)
 {
 	dma_addr_t buf_dma;
 	u32 *buf, saved_dma_rwctrl;
-	int ret;
+	int ret = 0;
 
 	buf = pci_alloc_consistent(tp->pdev, TEST_BUFFER_SIZE, &buf_dma);
 	if (!buf) {
@@ -13536,6 +13544,9 @@ static int __devinit tg3_test_dma(struct tg3 *tp)
 
 	tp->dma_rwctrl = tg3_calc_dma_bndry(tp, tp->dma_rwctrl);
 
+	if (GET_ASIC_REV(tp->pci_chip_rev_id) == ASIC_REV_5717)
+		goto out;
+
 	if (tp->tg3_flags2 & TG3_FLG2_PCI_EXPRESS) {
 		/* DMA read watermark not used on PCIE */
 		tp->dma_rwctrl |= 0x00180000;
@@ -13608,7 +13619,6 @@ static int __devinit tg3_test_dma(struct tg3 *tp)
 	tg3_switch_clocks(tp);
 #endif
 
-	ret = 0;
 	if (GET_ASIC_REV(tp->pci_chip_rev_id) != ASIC_REV_5700 &&
 	    GET_ASIC_REV(tp->pci_chip_rev_id) != ASIC_REV_5701)
 		goto out;

drivers/net/tg3.h

@@ -142,8 +142,7 @@
 #define   METAL_REV_B1			 0x01
 #define   METAL_REV_B2			 0x02
 #define TG3PCI_DMA_RW_CTRL		0x0000006c
-#define  DMA_RWCTRL_MIN_DMA		 0x000000ff
-#define  DMA_RWCTRL_MIN_DMA_SHIFT	 0
+#define  DMA_RWCTRL_DIS_CACHE_ALIGNMENT  0x00000001
 #define  DMA_RWCTRL_READ_BNDRY_MASK	 0x00000700
 #define  DMA_RWCTRL_READ_BNDRY_DISAB	 0x00000000
 #define  DMA_RWCTRL_READ_BNDRY_16	 0x00000100