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authorstephen hemminger <shemminger@vyatta.com>2011-11-17 14:37:23 +0000
committerDavid S. Miller <davem@davemloft.net>2011-11-17 21:43:57 -0500
commit738a849c8eef4787a526d95763f985b8c1cb68e4 (patch)
tree8e172b7f8b7d02929cc2045b7bd26e66d4248b24 /drivers/net
parent4a8bb7e27fbb68da888b55f26defd2855225b2d5 (diff)
sky2: enforce minimum ring size
The hardware has a restriction that the minimum ring size possible is 128. The number of elements used is controlled by tx_pending and the overall number of elements in the ring tx_ring_size, therefore it is okay to limit the number of elements in use to a small value (63) but still provide a bigger ring. Signed-off-by: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net')
-rw-r--r--drivers/net/ethernet/marvell/sky2.c14
1 files changed, 12 insertions, 2 deletions
diff --git a/drivers/net/ethernet/marvell/sky2.c b/drivers/net/ethernet/marvell/sky2.c
index 539de09cffc9..d99687177704 100644
--- a/drivers/net/ethernet/marvell/sky2.c
+++ b/drivers/net/ethernet/marvell/sky2.c
@@ -4088,6 +4088,16 @@ static int sky2_set_coalesce(struct net_device *dev,
return 0;
}
+/*
+ * Hardware is limited to min of 128 and max of 2048 for ring size
+ * and rounded up to next power of two
+ * to avoid division in modulus calclation
+ */
+static unsigned long roundup_ring_size(unsigned long pending)
+{
+ return max(128ul, roundup_pow_of_two(pending+1));
+}
+
static void sky2_get_ringparam(struct net_device *dev,
struct ethtool_ringparam *ering)
{
@@ -4115,7 +4125,7 @@ static int sky2_set_ringparam(struct net_device *dev,
sky2->rx_pending = ering->rx_pending;
sky2->tx_pending = ering->tx_pending;
- sky2->tx_ring_size = roundup_pow_of_two(sky2->tx_pending+1);
+ sky2->tx_ring_size = roundup_ring_size(sky2->tx_pending);
return sky2_reattach(dev);
}
@@ -4709,7 +4719,7 @@ static __devinit struct net_device *sky2_init_netdev(struct sky2_hw *hw,
spin_lock_init(&sky2->phy_lock);
sky2->tx_pending = TX_DEF_PENDING;
- sky2->tx_ring_size = roundup_pow_of_two(TX_DEF_PENDING+1);
+ sky2->tx_ring_size = roundup_ring_size(TX_DEF_PENDING);
sky2->rx_pending = RX_DEF_PENDING;
hw->dev[port] = dev;