[PATCH 37/78] dp8393x: Clear descriptor in_use field to release packet

[Michael Roth]

From: Finn Thain <fthain@telegraphics.com.au>

When the SONIC receives a packet into the last available descriptor, it
retains ownership of that descriptor for as long as necessary.

Section 3.4.7 of the datasheet says,

    When the system appends more descriptors, the SONIC releases ownership
    of the descriptor after writing 0000h to the RXpkt.in_use field.

The packet can now be processed by the host, so raise a PKTRX interrupt,
just like the normal case.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Tested-by: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Jason Wang <jasowang@redhat.com>
(cherry picked from commit d9fae13196a31716f45dcddcdd958fbb8e59b35a)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
---
 hw/net/dp8393x.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/hw/net/dp8393x.c b/hw/net/dp8393x.c
index 0e9061d831..4ce2ef818b 100644
--- a/hw/net/dp8393x.c
+++ b/hw/net/dp8393x.c
@@ -809,7 +809,17 @@ static ssize_t dp8393x_receive(NetClientState *nc, const 
uint8_t * buf,
             return -1;
         }
         /* Link has been updated by host */
+
+        /* Clear in_use */
+        size = sizeof(uint16_t) * width;
+        address = dp8393x_crda(s) + sizeof(uint16_t) * 6 * width;
+        dp8393x_put(s, width, 0, 0);
+        address_space_rw(&s->as, address, MEMTXATTRS_UNSPECIFIED,
+                         (uint8_t *)s->data, size, 1);
+
+        /* Move to next descriptor */
         s->regs[SONIC_CRDA] = s->regs[SONIC_LLFA];
+        s->regs[SONIC_ISR] |= SONIC_ISR_PKTRX;
     }
 
     /* Save current position */
-- 
2.17.1