Declare TX registers as MMIO region, split it out
of the current mixed RAM/MMIO region.

The memory flat view becomes:

  (qemu) info mtree -f
  FlatView #0
   Root memory region: system
    0000000081000000-00000000810007e3 (prio 0, i/o): xlnx.xps-ethernetlite
    00000000810007e4-00000000810007f3 (prio 0, i/o): ethlite.mdio
    00000000810007f4-00000000810007f7 (prio 0, i/o): ethlite.tx[0]io
    00000000810007f8-0000000081000ff3 (prio 0, i/o): xlnx.xps-ethernetlite @00000000000007f8
    0000000081000ff4-0000000081000ff7 (prio 0, i/o): ethlite.tx[1]io
    0000000081000ff8-00000000810017fb (prio 0, i/o): xlnx.xps-ethernetlite @0000000000000ff8
    00000000810017fc-00000000810017ff (prio 0, i/o): ethlite.rx[0]io
    0000000081001800-0000000081001ffb (prio 0, i/o): xlnx.xps-ethernetlite @0000000000001800
    0000000081001ffc-0000000081001fff (prio 0, i/o): ethlite.rx[1]io

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@amd.com>
---
 hw/net/xilinx_ethlite.c | 73 ++++++++++++++++++++++++++++++++++-------
 1 file changed, 61 insertions(+), 12 deletions(-)

diff --git a/hw/net/xilinx_ethlite.c b/hw/net/xilinx_ethlite.c
index d8f5a06182..b105fb7524 100644
--- a/hw/net/xilinx_ethlite.c
+++ b/hw/net/xilinx_ethlite.c
@@ -41,11 +41,11 @@
 #define R_TX_BUF0     0
 #define BUFSZ_MAX      0x07e4
 #define A_MDIO_BASE    0x07e4
-#define R_TX_LEN0     (0x07f4 / 4)
+#define A_TX_BASE0     0x07f4
 #define R_TX_GIE0     (0x07f8 / 4)
 #define R_TX_CTRL0    (0x07fc / 4)
 #define R_TX_BUF1     (0x0800 / 4)
-#define R_TX_LEN1     (0x0ff4 / 4)
+#define A_TX_BASE1     0x0ff4
 #define R_TX_CTRL1    (0x0ffc / 4)
 
 #define R_RX_BUF0     (0x1000 / 4)
@@ -54,6 +54,11 @@
 #define A_RX_BASE1     0x1ffc
 #define R_MAX         (0x2000 / 4)
 
+enum {
+    TX_LEN =  0,
+    TX_MAX
+};
+
 enum {
     RX_CTRL = 0,
     RX_MAX
@@ -67,6 +72,7 @@ enum {
 
 typedef struct XlnxXpsEthLitePort
 {
+    MemoryRegion txio;
     MemoryRegion rxio;
 
     struct {
@@ -126,6 +132,52 @@ static void *rxbuf_ptr(XlnxXpsEthLite *s, unsigned port_index)
     return &s->regs[rxbase + R_RX_BUF0];
 }
 
+static uint64_t port_tx_read(void *opaque, hwaddr addr, unsigned int size)
+{
+    XlnxXpsEthLite *s = opaque;
+    unsigned port_index = addr_to_port_index(addr);
+    uint32_t r = 0;
+
+    switch (addr >> 2) {
+        case TX_LEN:
+            r = s->port[port_index].reg.tx_len;
+            break;
+        default:
+            g_assert_not_reached();
+    }
+
+    return r;
+}
+
+static void port_tx_write(void *opaque, hwaddr addr, uint64_t value,
+                          unsigned int size)
+{
+    XlnxXpsEthLite *s = opaque;
+    unsigned port_index = addr_to_port_index(addr);
+
+    switch (addr >> 2) {
+        case TX_LEN:
+            s->port[port_index].reg.tx_len = value;
+            break;
+        default:
+            g_assert_not_reached();
+    }
+}
+
+static const MemoryRegionOps eth_porttx_ops = {
+        .read = port_tx_read,
+        .write = port_tx_write,
+        .endianness = DEVICE_NATIVE_ENDIAN,
+        .impl = {
+            .min_access_size = 4,
+            .max_access_size = 4,
+        },
+        .valid = {
+            .min_access_size = 4,
+            .max_access_size = 4,
+        },
+};
+
 static uint64_t port_rx_read(void *opaque, hwaddr addr, unsigned int size)
 {
     XlnxXpsEthLite *s = opaque;
@@ -190,11 +242,6 @@ eth_read(void *opaque, hwaddr addr, unsigned int size)
             r = s->port[port_index].reg.tx_gie;
             break;
 
-        case R_TX_LEN0:
-        case R_TX_LEN1:
-            r = s->port[port_index].reg.tx_len;
-            break;
-
         case R_TX_CTRL1:
         case R_TX_CTRL0:
             r = s->port[port_index].reg.tx_ctrl;
@@ -240,11 +287,6 @@ eth_write(void *opaque, hwaddr addr,
             break;
 
         /* Keep these native.  */
-        case R_TX_LEN0:
-        case R_TX_LEN1:
-            s->port[port_index].reg.tx_len = value;
-            break;
-
         case R_TX_GIE0:
             s->port[port_index].reg.tx_gie = value;
             break;
@@ -333,6 +375,13 @@ static void xilinx_ethlite_realize(DeviceState *dev, Error **errp)
                            sysbus_mmio_get_region(SYS_BUS_DEVICE(&s->mdio), 0));
 
     for (unsigned i = 0; i < 2; i++) {
+        memory_region_init_io(&s->port[i].txio, OBJECT(dev),
+                              &eth_porttx_ops, s,
+                              i ? "ethlite.tx[1]io" : "ethlite.tx[0]io",
+                              4 * TX_MAX);
+        memory_region_add_subregion(&s->mmio, i ? A_TX_BASE1 : A_TX_BASE0,
+                                    &s->port[i].txio);
+
         memory_region_init_io(&s->port[i].rxio, OBJECT(dev),
                               &eth_portrx_ops, s,
                               i ? "ethlite.rx[1]io" : "ethlite.rx[0]io",
-- 
2.45.2