tg3: Fix 5719 internal FIFO overflow problem

Under load, there an internal FIFO can overflow on the 5719.  The fix is
to scale back the PCIe maximum read request size based on the current
link speed and width.

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

2 files changed, 42 insertions, 3 deletions

diff --git a/drivers/net/tg3.c b/drivers/net/tg3.c
index 2624d714d16e..226e60dfaeaf 100644
--- a/drivers/net/tg3.c
+++ b/drivers/net/tg3.c
@@ -6985,7 +6985,7 @@ static void tg3_restore_pci_state(struct tg3 *tp)
 
         if (GET_ASIC_REV(tp->pci_chip_rev_id) != ASIC_REV_5785) {
                 if (tp->tg3_flags2 & TG3_FLG2_PCI_EXPRESS)
-                        pcie_set_readrq(tp->pdev, 4096);
+                        pcie_set_readrq(tp->pdev, tp->pcie_readrq);
                 else {
                         pci_write_config_byte(tp->pdev, PCI_CACHE_LINE_SIZE,
                                               tp->pci_cacheline_sz);
@@ -7179,7 +7179,7 @@ static int tg3_chip_reset(struct tg3 *tp)
                                       tp->pcie_cap + PCI_EXP_DEVCTL,
                                       val16);
 
-                pcie_set_readrq(tp->pdev, 4096);
+                pcie_set_readrq(tp->pdev, tp->pcie_readrq);
 
                 /* Clear error status */
                 pci_write_config_word(tp->pdev,
@@ -13366,7 +13366,45 @@ static int __devinit tg3_get_invariants(struct tg3 *tp)
 
                 tp->tg3_flags2 |= TG3_FLG2_PCI_EXPRESS;
 
-                pcie_set_readrq(tp->pdev, 4096);
+                tp->pcie_readrq = 4096;
+                if (GET_ASIC_REV(tp->pci_chip_rev_id) == ASIC_REV_5719) {
+                        u16 word;
+
+                        pci_read_config_word(tp->pdev,
+                                             tp->pcie_cap + PCI_EXP_LNKSTA,
+                                             &word);
+                        switch (word & PCI_EXP_LNKSTA_CLS) {
+                        case PCI_EXP_LNKSTA_CLS_2_5GB:
+                                word &= PCI_EXP_LNKSTA_NLW;
+                                word >>= PCI_EXP_LNKSTA_NLW_SHIFT;
+                                switch (word) {
+                                case 2:
+                                        tp->pcie_readrq = 2048;
+                                        break;
+                                case 4:
+                                        tp->pcie_readrq = 1024;
+                                        break;
+                                }
+                                break;
+
+                        case PCI_EXP_LNKSTA_CLS_5_0GB:
+                                word &= PCI_EXP_LNKSTA_NLW;
+                                word >>= PCI_EXP_LNKSTA_NLW_SHIFT;
+                                switch (word) {
+                                case 1:
+                                        tp->pcie_readrq = 2048;
+                                        break;
+                                case 2:
+                                        tp->pcie_readrq = 1024;
+                                        break;
+                                case 4:
+                                        tp->pcie_readrq = 512;
+                                        break;
+                                }
+                        }
+                }
+
+                pcie_set_readrq(tp->pdev, tp->pcie_readrq);
 
                 pci_read_config_word(tp->pdev,
                                      tp->pcie_cap + PCI_EXP_LNKCTL,
diff --git a/drivers/net/tg3.h b/drivers/net/tg3.h
index 06a4e7e8fff3..410703684e39 100644
--- a/drivers/net/tg3.h
+++ b/drivers/net/tg3.h
@@ -2948,6 +2948,7 @@ struct tg3 {
         int                             pcix_cap;
         int                             pcie_cap;
         };
+        int                             pcie_readrq;
 
         struct mii_bus                  *mdio_bus;
         int                             mdio_irq[PHY_MAX_ADDR];