net: dwc_eth_qos: Invalidate RX packet DMA buffer

This patch prevents an issue where the RX packet might have been
accessed by the CPU, which now has cached data from the packet in
the caches and possibly various write buffers, and these data may
be evicted from the caches into the DRAM while the buffer is also
written by the DMA.

By invalidating the buffer after the CPU accessed it and before the
DMA populates the buffer, it is assured that the buffer will not be
corrupted.

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 2b37cc3cded7c1b999554165dce806b8146c9313..a195fe5c2753b7a153806670c0f1671aff699a0d 100644 (file)
--- a/drivers/net/dwc_eth_qos.c
+++ b/drivers/net/dwc_eth_qos.c
@@ -1476,6 +1476,9 @@ static int eqos_free_pkt(struct udevice *dev, uchar *packet, int length)
        }
 
        rx_desc = &(eqos->rx_descs[eqos->rx_desc_idx]);
+
+       eqos->config->ops->eqos_inval_buffer(packet, length);
+
        rx_desc->des0 = (u32)(ulong)packet;
        rx_desc->des1 = 0;
        rx_desc->des2 = 0;
@@ -1538,6 +1541,9 @@ static int eqos_probe_resources_core(struct udevice *dev)
        }
        debug("%s: rx_pkt=%p\n", __func__, eqos->rx_pkt);
 
+       eqos->config->ops->eqos_inval_buffer(eqos->rx_dma_buf,
+                       EQOS_MAX_PACKET_SIZE * EQOS_DESCRIPTORS_RX);
+
        debug("%s: OK\n", __func__);
        return 0;