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authorStephen Hemminger <shemminger@linux-foundation.org>2007-05-14 12:38:15 -0700
committerJeff Garzik <jeff@garzik.org>2007-05-17 20:43:14 -0400
commit50432cb534b566c4fd9e371fb37464a65ccd2391 (patch)
treeb9967313ebf46d37650fbbc66fb35240be1825c0 /drivers/net/sky2.c
parent84787e3fc38a4847e5d75388d5a7fb3cf6bd7834 (diff)
sky2: memory barriers change
Do some memory barrier changes for safety/perfomance: Don't need read after update to index, mmiowb() followed by read at end of irq is sufficient. Signed-off-by: Stephn Hemminger <shemminger@linux-foundation.org> Signed-off-by: Jeff Garzik <jeff@garzik.org>
Diffstat (limited to 'drivers/net/sky2.c')
-rw-r--r--drivers/net/sky2.c15
1 files changed, 11 insertions, 4 deletions
diff --git a/drivers/net/sky2.c b/drivers/net/sky2.c
index ccbd8c2674b0..832fd69a0e59 100644
--- a/drivers/net/sky2.c
+++ b/drivers/net/sky2.c
@@ -844,10 +844,12 @@ static inline struct tx_ring_info *tx_le_re(struct sky2_port *sky2,
/* Update chip's next pointer */
static inline void sky2_put_idx(struct sky2_hw *hw, unsigned q, u16 idx)
{
- q = Y2_QADDR(q, PREF_UNIT_PUT_IDX);
+ /* Make sure write' to descriptors are complete before we tell hardware */
wmb();
- sky2_write16(hw, q, idx);
- sky2_read16(hw, q);
+ sky2_write16(hw, Y2_QADDR(q, PREF_UNIT_PUT_IDX), idx);
+
+ /* Synchronize I/O on since next processor may write to tail */
+ mmiowb();
}
@@ -979,6 +981,7 @@ stopped:
/* reset the Rx prefetch unit */
sky2_write32(hw, Y2_QADDR(rxq, PREF_UNIT_CTRL), PREF_UNIT_RST_SET);
+ mmiowb();
}
/* Clean out receive buffer area, assumes receiver hardware stopped */
@@ -1198,7 +1201,7 @@ static int sky2_rx_start(struct sky2_port *sky2)
}
/* Tell chip about available buffers */
- sky2_write16(hw, Y2_QADDR(rxq, PREF_UNIT_PUT_IDX), sky2->rx_put);
+ sky2_put_idx(hw, rxq, sky2->rx_put);
return 0;
nomem:
sky2_rx_clean(sky2);
@@ -1540,6 +1543,8 @@ static void sky2_tx_complete(struct sky2_port *sky2, u16 done)
}
sky2->tx_cons = idx;
+ smp_mb();
+
if (tx_avail(sky2) > MAX_SKB_TX_LE + 4)
netif_wake_queue(dev);
}
@@ -2218,6 +2223,7 @@ force_update:
/* Fully processed status ring so clear irq */
sky2_write32(hw, STAT_CTRL, SC_STAT_CLR_IRQ);
+ mmiowb();
exit_loop:
if (buf_write[0]) {
@@ -2442,6 +2448,7 @@ static int sky2_poll(struct net_device *dev0, int *budget)
if (work_done < work_limit) {
netif_rx_complete(dev0);
+ /* end of interrupt, re-enables also acts as I/O synchronization */
sky2_read32(hw, B0_Y2_SP_LISR);
return 0;
} else {