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Commit 50432cb5 authored by Stephen Hemminger's avatar Stephen Hemminger Committed by Jeff Garzik
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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: default avatarStephn Hemminger <shemminger@linux-foundation.org>
Signed-off-by: default avatarJeff Garzik <jeff@garzik.org>
parent 84787e3f

drivers/net/sky2.c

+11 −4
Original line number Diff line number Diff line
@@ -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 {