3 files changed, 45 insertions, 9 deletions

diff --git a/drivers/net/tg3.c b/drivers/net/tg3.c
index b8f1524da557..caf4102b54ce 100644
--- a/drivers/net/tg3.c
+++ b/drivers/net/tg3.c
@@ -9552,12 +9552,36 @@ static int __devinit tg3_get_invariants(struct tg3 *tp)
                 }
         }
 
-        /* Find msi capability. */
+        /* The EPB bridge inside 5714, 5715, and 5780 cannot support
+         * DMA addresses > 40-bit. This bridge may have other additional
+         * 57xx devices behind it in some 4-port NIC designs for example.
+         * Any tg3 device found behind the bridge will also need the 40-bit
+         * DMA workaround.
+         */
         if (GET_ASIC_REV(tp->pci_chip_rev_id) == ASIC_REV_5780 ||
             GET_ASIC_REV(tp->pci_chip_rev_id) == ASIC_REV_5714) {
                 tp->tg3_flags2 |= TG3_FLG2_5780_CLASS;
+                tp->tg3_flags |= TG3_FLAG_40BIT_DMA_BUG;
                 tp->msi_cap = pci_find_capability(tp->pdev, PCI_CAP_ID_MSI);
         }
+        else {
+                struct pci_dev *bridge = NULL;
+
+                do {
+                        bridge = pci_get_device(PCI_VENDOR_ID_SERVERWORKS,
+                                                PCI_DEVICE_ID_SERVERWORKS_EPB,
+                                                bridge);
+                        if (bridge && bridge->subordinate &&
+                            (bridge->subordinate->number <=
+                             tp->pdev->bus->number) &&
+                            (bridge->subordinate->subordinate >=
+                             tp->pdev->bus->number)) {
+                                tp->tg3_flags |= TG3_FLAG_40BIT_DMA_BUG;
+                                pci_dev_put(bridge);
+                                break;
+                        }
+                } while (bridge);
+        }
 
         /* Initialize misc host control in PCI block. */
         tp->misc_host_ctrl |= (misc_ctrl_reg &
@@ -10303,7 +10327,14 @@ static int __devinit tg3_test_dma(struct tg3 *tp)
                     GET_ASIC_REV(tp->pci_chip_rev_id) == ASIC_REV_5704) {
                         u32 ccval = (tr32(TG3PCI_CLOCK_CTRL) & 0x1f);
 
-                        if (ccval == 0x6 || ccval == 0x7)
+                        /* If the 5704 is behind the EPB bridge, we can
+                         * do the less restrictive ONE_DMA workaround for
+                         * better performance.
+                         */
+                        if ((tp->tg3_flags & TG3_FLAG_40BIT_DMA_BUG) &&
+                            GET_ASIC_REV(tp->pci_chip_rev_id) == ASIC_REV_5704)
+                                tp->dma_rwctrl |= 0x8000;
+                        else if (ccval == 0x6 || ccval == 0x7)
                                 tp->dma_rwctrl |= DMA_RWCTRL_ONE_DMA;
 
                         /* Set bit 23 to enable PCIX hw bug fix */
@@ -10759,19 +10790,20 @@ static int __devinit tg3_init_one(struct pci_dev *pdev,
                 goto err_out_iounmap;
         }
 
-        /* 5714, 5715 and 5780 cannot support DMA addresses > 40-bit.
+        /* The EPB bridge inside 5714, 5715, and 5780 and any
+         * device behind the EPB cannot support DMA addresses > 40-bit.
          * On 64-bit systems with IOMMU, use 40-bit dma_mask.
          * On 64-bit systems without IOMMU, use 64-bit dma_mask and
          * do DMA address check in tg3_start_xmit().
          */
-        if (tp->tg3_flags2 & TG3_FLG2_5780_CLASS) {
+        if (tp->tg3_flags2 & TG3_FLG2_IS_5788)
+                persist_dma_mask = dma_mask = DMA_32BIT_MASK;
+        else if (tp->tg3_flags & TG3_FLAG_40BIT_DMA_BUG) {
                 persist_dma_mask = dma_mask = DMA_40BIT_MASK;
 #ifdef CONFIG_HIGHMEM
                 dma_mask = DMA_64BIT_MASK;
 #endif
-        } else if (tp->tg3_flags2 & TG3_FLG2_IS_5788)
-                persist_dma_mask = dma_mask = DMA_32BIT_MASK;
-        else
+        } else
                 persist_dma_mask = dma_mask = DMA_64BIT_MASK;
 
         /* Configure DMA attributes. */
@@ -10908,8 +10940,10 @@ static int __devinit tg3_init_one(struct pci_dev *pdev,
                (tp->tg3_flags & TG3_FLAG_SPLIT_MODE) != 0,
                (tp->tg3_flags2 & TG3_FLG2_NO_ETH_WIRE_SPEED) == 0,
                (tp->tg3_flags2 & TG3_FLG2_TSO_CAPABLE) != 0);
-        printk(KERN_INFO "%s: dma_rwctrl[%08x]\n",
-               dev->name, tp->dma_rwctrl);
+        printk(KERN_INFO "%s: dma_rwctrl[%08x] dma_mask[%d-bit]\n",
+               dev->name, tp->dma_rwctrl,
+               (pdev->dma_mask == DMA_32BIT_MASK) ? 32 :
+                (((u64) pdev->dma_mask == DMA_40BIT_MASK) ? 40 : 64));
 
         return 0;
 
diff --git a/drivers/net/tg3.h b/drivers/net/tg3.h
index 7f4b7f6ac40d..7e3b613afb29 100644
--- a/drivers/net/tg3.h
+++ b/drivers/net/tg3.h
@@ -2163,6 +2163,7 @@ struct tg3 {
 #define TG3_FLAG_10_100_ONLY            0x01000000
 #define TG3_FLAG_PAUSE_AUTONEG          0x02000000
 #define TG3_FLAG_IN_RESET_TASK          0x04000000
+#define TG3_FLAG_40BIT_DMA_BUG          0x08000000
 #define TG3_FLAG_BROKEN_CHECKSUMS       0x10000000
 #define TG3_FLAG_GOT_SERDES_FLOWCTL     0x20000000
 #define TG3_FLAG_SPLIT_MODE             0x40000000
diff --git a/include/linux/pci_ids.h b/include/linux/pci_ids.h
index 1709b5009d2e..751eea58bde8 100644
--- a/include/linux/pci_ids.h
+++ b/include/linux/pci_ids.h
@@ -1365,6 +1365,7 @@
 #define PCI_DEVICE_ID_SERVERWORKS_HE      0x0008
 #define PCI_DEVICE_ID_SERVERWORKS_LE      0x0009
 #define PCI_DEVICE_ID_SERVERWORKS_GCNB_LE 0x0017
+#define PCI_DEVICE_ID_SERVERWORKS_EPB     0x0103
 #define PCI_DEVICE_ID_SERVERWORKS_OSB4    0x0200
 #define PCI_DEVICE_ID_SERVERWORKS_CSB5    0x0201
 #define PCI_DEVICE_ID_SERVERWORKS_CSB6    0x0203