From fa10db3e54c9ef3f62871a9e2f74e89298628b28 Mon Sep 17 00:00:00 2001
From: Jani Paalijarvi <jani.paalijarvi@unikie.com>
Date: Wed, 4 Dec 2024 13:21:01 +0200
Subject: [PATCH] mpfs_ethernet.c: Modify interrupt worker

Process all data in the buffer which have come during the interrupt work.

It's still possible to lost an interrupt because re-enabling interrupts does not
trigger an interrupt from events that have occured during interrupts were disabled.

Signed-off-by: Jani Paalijarvi <jani.paalijarvi@unikie.com>
---
 arch/risc-v/src/mpfs/mpfs_ethernet.c | 28 ++++++++++++++++++++++++----
 1 file changed, 24 insertions(+), 4 deletions(-)

diff --git a/arch/risc-v/src/mpfs/mpfs_ethernet.c b/arch/risc-v/src/mpfs/mpfs_ethernet.c
index 6750523739a09..3407f2b731a68 100644
--- a/arch/risc-v/src/mpfs/mpfs_ethernet.c
+++ b/arch/risc-v/src/mpfs/mpfs_ethernet.c
@@ -964,6 +964,7 @@ static void mpfs_interrupt_work(void *arg)
   uint32_t tsr;
   uint32_t regval;
   uint32_t queue = 0; /* todo: get from arg */
+  uint32_t retries = 5;
 
   /* Process pending Ethernet interrupts */
 
@@ -983,7 +984,7 @@ static void mpfs_interrupt_work(void *arg)
    *   one to this bit.
    */
 
-  if (tsr != 0)
+  while (tsr != 0 && retries > 0)
     {
       ninfo("TX tsr=0x%X\n", tsr);
       uint32_t tx_error = 0;
@@ -1068,6 +1069,12 @@ static void mpfs_interrupt_work(void *arg)
 
           mpfs_txdone(priv, queue);
         }
+
+      /* Re-read transmit status */
+
+      tsr = mac_getreg(priv, TRANSMIT_STATUS);
+
+      retries--;
     }
 
   /* Check for the receipt of an RX packet.
@@ -1077,7 +1084,9 @@ static void mpfs_interrupt_work(void *arg)
    *   in memory. This indication is cleared by writing a one to this bit.
    */
 
-  if (rsr != 0)
+  retries = 5;
+
+  while (rsr != 0 && retries > 0)
     {
       uint32_t rx_error = 0;
       ninfo("RX: rsr=0x%X\n", rsr);
@@ -1095,7 +1104,7 @@ static void mpfs_interrupt_work(void *arg)
       if ((rsr & RECEIVE_STATUS_BUFFER_NOT_AVAILABLE) != 0)
         {
           ++rx_error;
-//          nerr("ERROR: Buffer not available RSR: %08" PRIx32 "\n", rsr);
+          nerr("ERROR: Buffer not available RSR: %08" PRIx32 "\n", rsr);
         }
 
       /* Check for HRESP not OK */
@@ -1112,7 +1121,7 @@ static void mpfs_interrupt_work(void *arg)
 
       if (rx_error != 0)
         {
-//          nerr("RX ERROR: reset\n");
+          nerr("RX ERROR: reset\n");
           mpfs_rxreset(priv);
           *priv->queue[queue].int_status = 0xffffffff;
           mac_putreg(priv, RECEIVE_STATUS, 0xffffffff);
@@ -1129,8 +1138,19 @@ static void mpfs_interrupt_work(void *arg)
 
           mpfs_receive(priv, queue);
         }
+
+      /* Re-read receive status */
+
+      rsr = mac_getreg(priv, RECEIVE_STATUS);
+
+      retries--;
     }
 
+  /* NOTE: We might lost an interrupt here.
+   * Re-enabling interrupts does not trigger an interrupt from events that
+   * have occured during interrupts were disabled.
+   */
+
   net_unlock();
 
   /* Re-enable Ethernet interrupts */