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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>
This commit is contained in:
Stephen Hemminger 2007-05-14 12:38:15 -07:00 committed by Jeff Garzik
parent 84787e3fc3
commit 50432cb534
1 changed files with 11 additions and 4 deletions
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15
drivers/net/sky2.c
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@ -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 {