Add memory barriers to kwgbe_send/recv
kwgbe_send/recv both have loops waiting for the hardware to set a bit. GCC 4.3.3 cleverly optimizes this to ... a while(1); loop. This patch introduces memory barriers to force re-loading of the transmit descriptor.
mb() wasn't defined for arm, but perhaps it should?
Signed-off-by: Simon Kagstrom simon.kagstrom@netinsight.net --- drivers/net/kirkwood_egiga.c | 4 ++++ 1 files changed, 4 insertions(+), 0 deletions(-)
diff --git a/drivers/net/kirkwood_egiga.c b/drivers/net/kirkwood_egiga.c index 3c5db19..abedf77 100644 --- a/drivers/net/kirkwood_egiga.c +++ b/drivers/net/kirkwood_egiga.c @@ -513,6 +513,8 @@ static int kwgbe_send(struct eth_device *dev, volatile void *dataptr, printf("Err..(%s) in xmit packet\n", __FUNCTION__); return -1; } + /* Memory barrier to see to it that cmd_sts is re-read */ + asm volatile("" : : : "memory"); }; return 0; } @@ -531,6 +533,8 @@ static int kwgbe_recv(struct eth_device *dev) debug("%s time out...\n", __FUNCTION__); return -1; } + /* Memory barrier to see to it that cmd_sts is re-read */ + asm volatile("" : : : "memory"); } while (p_rxdesc_curr->cmd_sts & KWGBE_BUFFER_OWNED_BY_DMA);
if (p_rxdesc_curr->byte_cnt != 0) {