[PATCH AUTOSEL 4.19 630/671] dpaa_eth: perform DMA unmapping before read

Sasha Levin
2020-01-16T17:13:59Z

From: Madalin Bucur <madalin.bucur@nxp.com>

[ Upstream commit c70fd3182caef014e6c628b412f81aa57a3ef9e4 ]

DMA unmapping is required before accessing the HW provided timestamping
information.

Fixes: 4664856e9ca2 ("dpaa_eth: add support for hardware timestamping")
Signed-off-by: Madalin Bucur <madalin.bucur@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
.../net/ethernet/freescale/dpaa/dpaa_eth.c | 32 ++++++++++---------
1 file changed, 17 insertions(+), 15 deletions(-)

diff --git a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
index 462bb8c4f80c..3cd62a71ddea 100644
--- a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
+++ b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
@@ -1620,18 +1620,6 @@ static struct sk_buff *dpaa_cleanup_tx_fd(const struct dpaa_priv *priv,
skbh = (struct sk_buff **)phys_to_virt(addr);
skb = *skbh;

- if (priv->tx_tstamp && skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP) {
- memset(&shhwtstamps, 0, sizeof(shhwtstamps));
-
- if (!fman_port_get_tstamp(priv->mac_dev->port[TX], (void *)skbh,
- &ns)) {
- shhwtstamps.hwtstamp = ns_to_ktime(ns);
- skb_tstamp_tx(skb, &shhwtstamps);
- } else {
- dev_warn(dev, "fman_port_get_tstamp failed!\n");
- }
- }
-
if (unlikely(qm_fd_get_format(fd) == qm_fd_sg)) {
nr_frags = skb_shinfo(skb)->nr_frags;
dma_unmap_single(dev, addr,
@@ -1654,14 +1642,28 @@ static struct sk_buff *dpaa_cleanup_tx_fd(const struct dpaa_priv *priv,
dma_unmap_page(dev, qm_sg_addr(&sgt[i]),
qm_sg_entry_get_len(&sgt[i]), dma_dir);
}
-
- /* Free the page frag that we allocated on Tx */
- skb_free_frag(phys_to_virt(addr));
} else {
dma_unmap_single(dev, addr,
skb_tail_pointer(skb) - (u8 *)skbh, dma_dir);
}

+ /* DMA unmapping is required before accessing the HW provided info */
+ if (priv->tx_tstamp && skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP) {
+ memset(&shhwtstamps, 0, sizeof(shhwtstamps));
+
+ if (!fman_port_get_tstamp(priv->mac_dev->port[TX], (void *)skbh,
+ &ns)) {
+ shhwtstamps.hwtstamp = ns_to_ktime(ns);
+ skb_tstamp_tx(skb, &shhwtstamps);
+ } else {
+ dev_warn(dev, "fman_port_get_tstamp failed!\n");
+ }
+ }
+
+ if (qm_fd_get_format(fd) == qm_fd_sg)
+ /* Free the page frag that we allocated on Tx */
+ skb_free_frag(phys_to_virt(addr));
+
return skb;
}

--
2.20.1