diff mbox series

[Stable-7.2.11,55/59] hw/net/lan9118: Replace magic '2048' value by MIL_TXFIFO_SIZE definition

Message ID 20240418200224.952785-14-mjt@tls.msk.ru
State New
Headers show
Series Patch Round-up for stable 7.2.11, freeze on 2024-04-20 | expand

Commit Message

Michael Tokarev April 18, 2024, 8:02 p.m. UTC 
From: Philippe Mathieu-Daudé <philmd@linaro.org>

The magic 2048 is explained in the LAN9211 datasheet (DS00002414A)
in chapter 1.4, "10/100 Ethernet MAC":

  The MAC Interface Layer (MIL), within the MAC, contains a
  2K Byte transmit and a 128 Byte receive FIFO which is separate
  from the TX and RX FIFOs. [...]

Note, the use of the constant in lan9118_receive() reveals that
our implementation is using the same buffer for both tx and rx.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20240409133801.23503-2-philmd@linaro.org>
(cherry picked from commit a45223467e4e185fff1c76a6483784fa379ded77)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
diff mbox series

Patch

diff --git a/hw/net/lan9118.c b/hw/net/lan9118.c
index bf81c84984..f269d72d9e 100644
--- a/hw/net/lan9118.c
+++ b/hw/net/lan9118.c
@@ -155,6 +155,12 @@  do { fprintf(stderr, "lan9118: error: " fmt , ## __VA_ARGS__);} while (0)
 
 #define GPT_TIMER_EN    0x20000000
 
+/*
+ * The MAC Interface Layer (MIL), within the MAC, contains a 2K Byte transmit
+ * and a 128 Byte receive FIFO which is separate from the TX and RX FIFOs.
+ */
+#define MIL_TXFIFO_SIZE         2048
+
 enum tx_state {
     TX_IDLE,
     TX_B,
@@ -171,7 +177,7 @@  typedef struct {
     int32_t pad;
     int32_t fifo_used;
     int32_t len;
-    uint8_t data[2048];
+    uint8_t data[MIL_TXFIFO_SIZE];
 } LAN9118Packet;
 
 static const VMStateDescription vmstate_lan9118_packet = {
@@ -187,7 +193,7 @@  static const VMStateDescription vmstate_lan9118_packet = {
         VMSTATE_INT32(pad, LAN9118Packet),
         VMSTATE_INT32(fifo_used, LAN9118Packet),
         VMSTATE_INT32(len, LAN9118Packet),
-        VMSTATE_UINT8_ARRAY(data, LAN9118Packet, 2048),
+        VMSTATE_UINT8_ARRAY(data, LAN9118Packet, MIL_TXFIFO_SIZE),
         VMSTATE_END_OF_LIST()
     }
 };
@@ -549,7 +555,7 @@  static ssize_t lan9118_receive(NetClientState *nc, const uint8_t *buf,
         return -1;
     }
 
-    if (size >= 2048 || size < 14) {
+    if (size >= MIL_TXFIFO_SIZE || size < 14) {
         return -1;
     }