[PATCH net-next 1/2] net: stmmac: Only enable enhanced addressing mode when needed

[Thierry Reding]

From: Thierry Reding <tred...@nvidia.com>

Enhanced addressing mode is only required when more than 32 bits need to
be addressed. Add a DMA configuration parameter to enable this mode only
when needed.

Signed-off-by: Thierry Reding <tred...@nvidia.com>
---
 drivers/net/ethernet/stmicro/stmmac/dwxgmac2_dma.c | 5 ++++-
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c  | 6 ++++++
 include/linux/stmmac.h                             | 1 +
 3 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_dma.c 
b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_dma.c
index 64956465c030..3e00fd8befcf 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_dma.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_dma.c
@@ -27,7 +27,10 @@ static void dwxgmac2_dma_init(void __iomem *ioaddr,
        if (dma_cfg->aal)
                value |= XGMAC_AAL;
 
-       writel(value | XGMAC_EAME, ioaddr + XGMAC_DMA_SYSBUS_MODE);
+       if (dma_cfg->eame)
+               value |= XGMAC_EAME;
+
+       writel(value, ioaddr + XGMAC_DMA_SYSBUS_MODE);
 }
 
 static void dwxgmac2_dma_init_chan(void __iomem *ioaddr,
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c 
b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 06ccd216ae90..ecd461207dbc 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -4497,6 +4497,12 @@ int stmmac_dvr_probe(struct device *device,
                if (!ret) {
                        dev_info(priv->device, "Using %d bits DMA width\n",
                                 priv->dma_cap.addr64);
+
+                       /*
+                        * If more than 32 bits can be addressed, make sure to
+                        * enable enhanced addressing mode.
+                        */
+                       priv->plat->dma_cfg->eame = true;
                } else {
                        ret = dma_set_mask_and_coherent(device, 
DMA_BIT_MASK(32));
                        if (ret) {
diff --git a/include/linux/stmmac.h b/include/linux/stmmac.h
index 7ad7ae35cf88..d300ac907c76 100644
--- a/include/linux/stmmac.h
+++ b/include/linux/stmmac.h
@@ -92,6 +92,7 @@ struct stmmac_dma_cfg {
        int fixed_burst;
        int mixed_burst;
        bool aal;
+       bool eame;
 };
 
 #define AXI_BLEN       7
-- 
2.23.0