[PATCH 4.20 12/32] net: stmmac: handle endianness in dwmac4_get_timestamp

From: Greg Kroah-Hartman
Date: Thu Feb 21 2019 - 09:43:54 EST


4.20-stable review patch. If anyone has any objections, please let me know.

------------------

[ Upstream commit 224babd62d6f19581757a6d8bae3bf9501fc10de ]

GMAC IP is little-endian and used on several kind of CPU (big or little
endian). Main callbacks functions of the stmmac drivers take care about
it. It was not the case for dwmac4_get_timestamp function.

Fixes: ba1ffd74df74 ("stmmac: fix PTP support for GMAC4")
Signed-off-by: Alexandre Torgue <alexandre.torgue@xxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c b/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c
index 20299f6f65fce..736e29635b772 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c
@@ -241,15 +241,18 @@ static inline void dwmac4_get_timestamp(void *desc, u32 ats, u64 *ts)
static int dwmac4_rx_check_timestamp(void *desc)
{
struct dma_desc *p = (struct dma_desc *)desc;
+ unsigned int rdes0 = le32_to_cpu(p->des0);
+ unsigned int rdes1 = le32_to_cpu(p->des1);
+ unsigned int rdes3 = le32_to_cpu(p->des3);
u32 own, ctxt;
int ret = 1;

- own = p->des3 & RDES3_OWN;
- ctxt = ((p->des3 & RDES3_CONTEXT_DESCRIPTOR)
+ own = rdes3 & RDES3_OWN;
+ ctxt = ((rdes3 & RDES3_CONTEXT_DESCRIPTOR)
>> RDES3_CONTEXT_DESCRIPTOR_SHIFT);

if (likely(!own && ctxt)) {
- if ((p->des0 == 0xffffffff) && (p->des1 == 0xffffffff))
+ if ((rdes0 == 0xffffffff) && (rdes1 == 0xffffffff))
/* Corrupted value */
ret = -EINVAL;
else
--
2.19.1