net: zynq_gem: Add check for 64-bit dma support by hardware

This patch throws an error if 64-bit support is expected
but DMA hardware is not capable of 64-bit support. It also
prints a debug message if DMA is capable of 64-bit but not
using it.

Signed-off-by: Siva Durga Prasad Paladugu <siva.durga.paladugu@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>

diff --git a/drivers/net/zynq_gem.c b/drivers/net/zynq_gem.c
index 1bcb6f08d5477ea09c13d60a6781d540feb89578..d2e251a789bb62d9dc209a2a822f963e3bd093e2 100644 (file)
--- a/drivers/net/zynq_gem.c
+++ b/drivers/net/zynq_gem.c
@@ -103,6 +103,8 @@ DECLARE_GLOBAL_DATA_PTR;
 
 #define ZYNQ_GEM_PCS_CTL_ANEG_ENBL     0x1000
 
+#define ZYNQ_GEM_DCFG_DBG6_DMA_64B     BIT(23)
+
 /* Use MII register 1 (MII status register) to detect PHY */
 #define PHY_DETECT_REG  1
 
@@ -151,7 +153,9 @@ struct zynq_gem_regs {
        u32 stat[STAT_SIZE]; /* 0x100 - Octects transmitted Low reg */
        u32 reserved9[20];
        u32 pcscntrl;
-       u32 reserved7[143];
+       u32 rserved12[36];
+       u32 dcfg6; /* 0x294 Design config reg6 */
+       u32 reserved7[106];
        u32 transmit_q1_ptr; /* 0x440 - Transmit priority queue 1 */
        u32 reserved8[15];
        u32 receive_q1_ptr; /* 0x480 - Receive priority queue 1 */
@@ -199,6 +203,7 @@ struct zynq_gem_priv {
        struct clk clk;
        u32 max_speed;
        bool int_pcs;
+       bool dma_64bit;
 };
 
 static u32 phy_setup_op(struct zynq_gem_priv *priv, u32 phy_addr, u32 regnum,
@@ -381,6 +386,23 @@ static int zynq_gem_init(struct udevice *dev)
        struct emac_bd *dummy_tx_bd = &priv->tx_bd[TX_FREE_DESC];
        struct emac_bd *dummy_rx_bd = &priv->tx_bd[TX_FREE_DESC + 2];
 
+       if (readl(&regs->dcfg6) & ZYNQ_GEM_DCFG_DBG6_DMA_64B)
+               priv->dma_64bit = true;
+       else
+               priv->dma_64bit = false;
+
+#if defined(CONFIG_PHYS_64BIT)
+       if (!priv->dma_64bit) {
+               printf("ERR: %s: Using 64-bit DMA but HW doesn't support it\n",
+                      __func__);
+               return -EINVAL;
+       }
+#else
+       if (priv->dma_64bit)
+               debug("WARN: %s: Not using 64-bit dma even HW supports it\n",
+                     __func__);
+#endif
+
        if (!priv->init) {
                /* Disable all interrupts */
                writel(0xFFFFFFFF, &regs->idr);