diff options
| author | Ruchika Gupta <ruchika.gupta@freescale.com> | 2012-04-19 02:27:11 +0000 |
|---|---|---|
| committer | Joe Hershberger <joe.hershberger@ni.com> | 2012-12-15 12:28:21 -0600 |
| commit | 776e66e8f1df7f092e6a543d47391a85509c1a2b (patch) | |
| tree | aac0b4fbc3069b855a4847674213ab5478cea7cc /drivers/net | |
| parent | ebbf0d20aa85f623c49b7ed3349ebfea450c152d (diff) | |
| download | u-boot-776e66e8f1df7f092e6a543d47391a85509c1a2b.tar.gz u-boot-776e66e8f1df7f092e6a543d47391a85509c1a2b.tar.xz u-boot-776e66e8f1df7f092e6a543d47391a85509c1a2b.zip | |
e1000e : Correct Rx Threshold granularity
In e1000e driver, Rx descriptor queue is used such that hardware can add only
one descriptor at a time. So the WTHRESH granularity in RXDCTL should be set
to single descriptor. This would ensure that every time controller fills a Rx
descriptor, it is flushed to host memory. Earlier this granularity was in
cache line units i.e 2 descriptors. This leads to controller always waiting
for 2 descriptors before flushing them out. But since not more than one Rx BD
is actually available , the accumulation condition never gets hit.
Signed-off-by: Ruchika Gupta <ruchika.gupta@freescale.com>
Signed-off-by: Vakul Garg <vakul@freescale.com>
Acked-by: Roy Zang <tie-fei.zang@freescale.com>
Diffstat (limited to 'drivers/net')
| -rw-r--r-- | drivers/net/e1000.c | 10 | ||||
| -rw-r--r-- | drivers/net/e1000.h | 1 |
2 files changed, 11 insertions, 0 deletions
diff --git a/drivers/net/e1000.c b/drivers/net/e1000.c index 2d4da4b386..8ba98b27d5 100644 --- a/drivers/net/e1000.c +++ b/drivers/net/e1000.c @@ -1688,6 +1688,16 @@ e1000_init_hw(struct eth_device *nic) E1000_WRITE_REG(hw, TXDCTL, ctrl); } + /* Set the receive descriptor write back policy */ + + if (hw->mac_type >= e1000_82571) { + ctrl = E1000_READ_REG(hw, RXDCTL); + ctrl = + (ctrl & ~E1000_RXDCTL_WTHRESH) | + E1000_RXDCTL_FULL_RX_DESC_WB; + E1000_WRITE_REG(hw, RXDCTL, ctrl); + } + switch (hw->mac_type) { default: break; diff --git a/drivers/net/e1000.h b/drivers/net/e1000.h index fd1d8f8717..1bbae5085a 100644 --- a/drivers/net/e1000.h +++ b/drivers/net/e1000.h @@ -1551,6 +1551,7 @@ struct e1000_hw { #define E1000_RXDCTL_HTHRESH 0x00003F00 /* RXDCTL Host Threshold */ #define E1000_RXDCTL_WTHRESH 0x003F0000 /* RXDCTL Writeback Threshold */ #define E1000_RXDCTL_GRAN 0x01000000 /* RXDCTL Granularity */ +#define E1000_RXDCTL_FULL_RX_DESC_WB 0x01010000 /* GRAN=1, WTHRESH=1 */ /* Transmit Descriptor Control */ #define E1000_TXDCTL_PTHRESH 0x0000003F /* TXDCTL Prefetch Threshold */ |