[PATCH 4.4 48/53] net/sonic: Use MMIO accessors

Greg Kroah-Hartman
2020-02-03T16:21:30Z

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

[ Upstream commit e3885f576196ddfc670b3d53e745de96ffcb49ab ]

The driver accesses descriptor memory which is simultaneously accessed by
the chip, so the compiler must not be allowed to re-order CPU accesses.
sonic_buf_get() used 'volatile' to prevent that. sonic_buf_put() should
have done so too but was overlooked.

Fixes: efcce839360f ("[PATCH] macsonic/jazzsonic network drivers update")
Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/natsemi/sonic.h | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/net/ethernet/natsemi/sonic.h b/drivers/net/ethernet/natsemi/sonic.h
index 1fd61d7f79bcb..a009a99c0e544 100644
--- a/drivers/net/ethernet/natsemi/sonic.h
+++ b/drivers/net/ethernet/natsemi/sonic.h
@@ -342,30 +342,30 @@ static void sonic_tx_timeout(struct net_device *dev);
as far as we can tell. */
/* OpenBSD calls this "SWO". I'd like to think that sonic_buf_put()
is a much better name. */
-static inline void sonic_buf_put(void* base, int bitmode,
+static inline void sonic_buf_put(u16 *base, int bitmode,
int offset, __u16 val)
{
if (bitmode)
#ifdef __BIG_ENDIAN
- ((__u16 *) base + (offset*2))[1] = val;
+ __raw_writew(val, base + (offset * 2) + 1);
#else
- ((__u16 *) base + (offset*2))[0] = val;
+ __raw_writew(val, base + (offset * 2) + 0);
#endif
else
- ((__u16 *) base)[offset] = val;
+ __raw_writew(val, base + (offset * 1) + 0);
}

-static inline __u16 sonic_buf_get(void* base, int bitmode,
+static inline __u16 sonic_buf_get(u16 *base, int bitmode,
int offset)
{
if (bitmode)
#ifdef __BIG_ENDIAN
- return ((volatile __u16 *) base + (offset*2))[1];
+ return __raw_readw(base + (offset * 2) + 1);
#else
- return ((volatile __u16 *) base + (offset*2))[0];
+ return __raw_readw(base + (offset * 2) + 0);
#endif
else
- return ((volatile __u16 *) base)[offset];
+ return __raw_readw(base + (offset * 1) + 0);
}

/* Inlines that you should actually use for reading/writing DMA buffers */
--
2.20.1