net: dwc_eth_qos: Invalidate RX descriptor before reading

The current code polls the RX desciptor ring for new packets by reading
the RX descriptor status. This works by accident, as the RX descriptors
are often in non-cacheable memory. However, the driver does support use
of RX descriptors in cacheable memory.

This patch adds a missing RX descriptor invalidation, which assures the
CPU will read a fresh copy of the RX descriptor instead of a cached one.

Reviewed-by: Patrick Delaunay <patrick.delaunay@st.com>
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Joe Hershberger <joe.hershberger@ni.com>
Cc: Patrice Chotard <patrice.chotard@st.com>
Cc: Patrick Delaunay <patrick.delaunay@st.com>
Cc: Ramon Fried <rfried.dev@gmail.com>
Cc: Stephen Warren <swarren@nvidia.com>

diff --git a/drivers/net/dwc_eth_qos.c b/drivers/net/dwc_eth_qos.c
index e33f3045fea4a362f8118acb4278bc3633a78358..2b37cc3cded7c1b999554165dce806b8146c9313 100644 (file)
--- a/drivers/net/dwc_eth_qos.c
+++ b/drivers/net/dwc_eth_qos.c
@@ -1443,6 +1443,7 @@ static int eqos_recv(struct udevice *dev, int flags, uchar **packetp)
        debug("%s(dev=%p, flags=%x):\n", __func__, dev, flags);
 
        rx_desc = &(eqos->rx_descs[eqos->rx_desc_idx]);
+       eqos->config->ops->eqos_inval_desc(rx_desc);
        if (rx_desc->des3 & EQOS_DESC3_OWN) {
                debug("%s: RX packet not available\n", __func__);
                return -EAGAIN;