hw/net/xilinx_ethlite: Introduce rxbuf_ptr() helper

rxbuf_ptr() points to the beginning of a (RAM) RX buffer
within the device state.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@amd.com>
Message-Id: <20241112181044.92193-11-philmd@linaro.org>

hw/net/xilinx_ethlite.c

@@ -60,6 +60,12 @@
 #define CTRL_P     0x2
 #define CTRL_S     0x1
 
+typedef struct XlnxXpsEthLitePort {
+    struct {
+        uint32_t rx_ctrl;
+    } reg;
+} XlnxXpsEthLitePort;
+
 #define TYPE_XILINX_ETHLITE "xlnx.xps-ethernetlite"
 OBJECT_DECLARE_SIMPLE_TYPE(XlnxXpsEthLite, XILINX_ETHLITE)
 
@@ -77,6 +83,7 @@ struct XlnxXpsEthLite
     unsigned int port_index; /* dual port RAM index */
 
     UnimplementedDeviceState mdio;
+    XlnxXpsEthLitePort port[2];
     uint32_t regs[R_MAX];
 };
 
@@ -100,10 +107,18 @@ static void *txbuf_ptr(XlnxXpsEthLite *s, unsigned port_index)
     return &s->regs[rxbase + R_TX_BUF0];
 }
 
+static void *rxbuf_ptr(XlnxXpsEthLite *s, unsigned port_index)
+{
+    unsigned int rxbase = port_index * (0x800 / 4);
+
+    return &s->regs[rxbase + R_RX_BUF0];
+}
+
 static uint64_t
 eth_read(void *opaque, hwaddr addr, unsigned int size)
 {
     XlnxXpsEthLite *s = opaque;
+    unsigned port_index = addr_to_port_index(addr);
     uint32_t r = 0;
 
     addr >>= 2;
@@ -115,9 +130,12 @@ eth_read(void *opaque, hwaddr addr, unsigned int size)
         case R_TX_LEN1:
         case R_TX_CTRL1:
         case R_TX_CTRL0:
+            r = s->regs[addr];
+            break;
+
         case R_RX_CTRL1:
         case R_RX_CTRL0:
-            r = s->regs[addr];
+            r = s->port[port_index].reg.rx_ctrl;
             break;
 
         default:
@@ -167,7 +185,9 @@ eth_write(void *opaque, hwaddr addr,
             if (!(value & CTRL_S)) {
                 qemu_flush_queued_packets(qemu_get_queue(s->nic));
             }
-            /* fall through */
+            s->port[port_index].reg.rx_ctrl = value;
+            break;
+
         case R_TX_LEN0:
         case R_TX_LEN1:
         case R_TX_GIE0:
@@ -197,22 +217,21 @@ static const MemoryRegionOps eth_ops = {
 static bool eth_can_rx(NetClientState *nc)
 {
     XlnxXpsEthLite *s = qemu_get_nic_opaque(nc);
-    unsigned int rxbase = s->port_index * (0x800 / 4);
 
-    return !(s->regs[rxbase + R_RX_CTRL0] & CTRL_S);
+    return !(s->port[s->port_index].reg.rx_ctrl & CTRL_S);
 }
 
 static ssize_t eth_rx(NetClientState *nc, const uint8_t *buf, size_t size)
 {
     XlnxXpsEthLite *s = qemu_get_nic_opaque(nc);
-    unsigned int rxbase = s->port_index * (0x800 / 4);
+    unsigned int port_index = s->port_index;
 
     /* DA filter.  */
     if (!(buf[0] & 0x80) && memcmp(&s->conf.macaddr.a[0], buf, 6))
         return size;
 
-    if (s->regs[rxbase + R_RX_CTRL0] & CTRL_S) {
-        trace_ethlite_pkt_lost(s->regs[R_RX_CTRL0]);
+    if (s->port[port_index].reg.rx_ctrl & CTRL_S) {
+        trace_ethlite_pkt_lost(s->port[port_index].reg.rx_ctrl);
         return -1;
     }
 
@@ -220,10 +239,10 @@ static ssize_t eth_rx(NetClientState *nc, const uint8_t *buf, size_t size)
         trace_ethlite_pkt_size_too_big(size);
         return -1;
     }
-    memcpy(&s->regs[rxbase + R_RX_BUF0], buf, size);
+    memcpy(rxbuf_ptr(s, port_index), buf, size);
 
-    s->regs[rxbase + R_RX_CTRL0] |= CTRL_S;
-    if (s->regs[R_RX_CTRL0] & CTRL_I) {
+    s->port[port_index].reg.rx_ctrl |= CTRL_S;
+    if (s->port[port_index].reg.rx_ctrl & CTRL_I) {
         eth_pulse_irq(s);
     }