NTB: Enable Snoop on Primary Side
Enable Snoop from Primary to Secondary side on BAR23 and BAR45 on all
TLPs. Previously, Snoop was only enabled from Secondary to Primary
side. This can have a performance improvement on some workloads.
Also, make the code more obvious about how the link is being enabled.
Signed-off-by: Jon Mason <jon.mason@intel.com>
diff --git a/drivers/ntb/ntb_hw.c b/drivers/ntb/ntb_hw.c
index 391c377..80505ae 100644
--- a/drivers/ntb/ntb_hw.c
+++ b/drivers/ntb/ntb_hw.c
@@ -1316,10 +1316,16 @@
{
if (ndev->conn_type == NTB_CONN_TRANSPARENT)
ntb_link_event(ndev, NTB_LINK_UP);
- else
+ else {
+ u32 ntb_cntl;
+
/* Let's bring the NTB link up */
- writel(NTB_CNTL_BAR23_SNOOP | NTB_CNTL_BAR45_SNOOP,
- ndev->reg_ofs.lnk_cntl);
+ ntb_cntl = readl(ndev->reg_ofs.lnk_cntl);
+ ntb_cntl &= ~(NTB_CNTL_LINK_DISABLE | NTB_CNTL_CFG_LOCK);
+ ntb_cntl |= NTB_CNTL_P2S_BAR23_SNOOP | NTB_CNTL_S2P_BAR23_SNOOP;
+ ntb_cntl |= NTB_CNTL_P2S_BAR45_SNOOP | NTB_CNTL_S2P_BAR45_SNOOP;
+ writel(ntb_cntl, ndev->reg_ofs.lnk_cntl);
+ }
}
static void ntb_hw_link_down(struct ntb_device *ndev)
@@ -1333,8 +1339,9 @@
/* Bring NTB link down */
ntb_cntl = readl(ndev->reg_ofs.lnk_cntl);
- ntb_cntl &= ~(NTB_CNTL_BAR23_SNOOP | NTB_CNTL_BAR45_SNOOP);
- ntb_cntl |= NTB_CNTL_LINK_DISABLE;
+ ntb_cntl &= ~(NTB_CNTL_P2S_BAR23_SNOOP | NTB_CNTL_S2P_BAR23_SNOOP);
+ ntb_cntl &= ~(NTB_CNTL_P2S_BAR45_SNOOP | NTB_CNTL_S2P_BAR45_SNOOP);
+ ntb_cntl |= NTB_CNTL_LINK_DISABLE | NTB_CNTL_CFG_LOCK;
writel(ntb_cntl, ndev->reg_ofs.lnk_cntl);
}