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path: root/drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c
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Diffstat (limited to 'drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c')
-rw-r--r--drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c13
1 files changed, 11 insertions, 2 deletions
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c b/drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c
index 90383abafa66..f5581db0ba9b 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c
@@ -218,11 +218,18 @@ static void dwmac1000_dump_dma_regs(void __iomem *ioaddr, u32 *reg_space)
readl(ioaddr + DMA_BUS_MODE + i * 4);
}
-static void dwmac1000_get_hw_feature(void __iomem *ioaddr,
- struct dma_features *dma_cap)
+static int dwmac1000_get_hw_feature(void __iomem *ioaddr,
+ struct dma_features *dma_cap)
{
u32 hw_cap = readl(ioaddr + DMA_HW_FEATURE);
+ if (!hw_cap) {
+ /* 0x00000000 is the value read on old hardware that does not
+ * implement this register
+ */
+ return -EOPNOTSUPP;
+ }
+
dma_cap->mbps_10_100 = (hw_cap & DMA_HW_FEAT_MIISEL);
dma_cap->mbps_1000 = (hw_cap & DMA_HW_FEAT_GMIISEL) >> 1;
dma_cap->half_duplex = (hw_cap & DMA_HW_FEAT_HDSEL) >> 2;
@@ -252,6 +259,8 @@ static void dwmac1000_get_hw_feature(void __iomem *ioaddr,
dma_cap->number_tx_channel = (hw_cap & DMA_HW_FEAT_TXCHCNT) >> 22;
/* Alternate (enhanced) DESC mode */
dma_cap->enh_desc = (hw_cap & DMA_HW_FEAT_ENHDESSEL) >> 24;
+
+ return 0;
}
static void dwmac1000_rx_watchdog(void __iomem *ioaddr, u32 riwt,