stmmac: Configure Flow Control to work correctly based on rxfifo size

[mirror_ubuntu-artful-kernel.git] / drivers / net / ethernet / stmicro / stmmac / dwmac1000_dma.c

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c b/drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c
index 59d92e811750295e6125cdfcf4f410da6aa21bba..0e8937c1184af811490bf232a05a100af06a9373 100644 (file)
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c
@@ -106,8 +106,29 @@ static int dwmac1000_dma_init(void __iomem *ioaddr, int pbl, int fb, int mb,
        return 0;
 }
 
+static u32 dwmac1000_configure_fc(u32 csr6, int rxfifosz)
+{
+       csr6 &= ~DMA_CONTROL_RFA_MASK;
+       csr6 &= ~DMA_CONTROL_RFD_MASK;
+
+       /* Leave flow control disabled if receive fifo size is less than
+        * 4K or 0. Otherwise, send XOFF when fifo is 1K less than full,
+        * and send XON when 2K less than full.
+        */
+       if (rxfifosz < 4096) {
+               csr6 &= ~DMA_CONTROL_EFC;
+               pr_debug("GMAC: disabling flow control, rxfifo too small(%d)\n",
+                        rxfifosz);
+       } else {
+               csr6 |= DMA_CONTROL_EFC;
+               csr6 |= RFA_FULL_MINUS_1K;
+               csr6 |= RFD_FULL_MINUS_2K;
+       }
+       return csr6;
+}
+
 static void dwmac1000_dma_operation_mode(void __iomem *ioaddr, int txmode,
-                                        int rxmode)
+                                        int rxmode, int rxfifosz)
 {
        u32 csr6 = readl(ioaddr + DMA_CONTROL);
 
@@ -153,6 +174,9 @@ static void dwmac1000_dma_operation_mode(void __iomem *ioaddr, int txmode,
                        csr6 |= DMA_CONTROL_RTC_128;
        }
 
+       /* Configure flow control based on rx fifo size */
+       csr6 = dwmac1000_configure_fc(csr6, rxfifosz);
+
        writel(csr6, ioaddr + DMA_CONTROL);
 }