ntb: ntb_hw_intel: link_poll isn't clearing the pending status properly

On Skylake hardware, the link_poll isn't clearing the pending interrupt
bit.  Adding a new function for SKX that handles clearing of status bit the
right way.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Fixes: 783dfa6c ("ntb: Adding Skylake Xeon NTB support")
Signed-off-by: Jon Mason <jdmason@kudzu.us>

diff --git a/drivers/ntb/hw/intel/ntb_hw_intel.c b/drivers/ntb/hw/intel/ntb_hw_intel.c
index eca9688..c002384 100644 (file)
--- a/drivers/ntb/hw/intel/ntb_hw_intel.c
+++ b/drivers/ntb/hw/intel/ntb_hw_intel.c
@@ -1629,6 +1629,28 @@ static void atom_deinit_dev(struct intel_ntb_dev *ndev)
 
 /* Skylake Xeon NTB */
 
+static int skx_poll_link(struct intel_ntb_dev *ndev)
+{
+       u16 reg_val;
+       int rc;
+
+       ndev->reg->db_iowrite(ndev->db_link_mask,
+                             ndev->self_mmio +
+                             ndev->self_reg->db_clear);
+
+       rc = pci_read_config_word(ndev->ntb.pdev,
+                                 SKX_LINK_STATUS_OFFSET, &reg_val);
+       if (rc)
+               return 0;
+
+       if (reg_val == ndev->lnk_sta)
+               return 0;
+
+       ndev->lnk_sta = reg_val;
+
+       return 1;
+}
+
 static u64 skx_db_ioread(void __iomem *mmio)
 {
        return ioread64(mmio);
@@ -2852,7 +2874,7 @@ static struct intel_b2b_addr xeon_b2b_dsd_addr = {
 };
 
 static const struct intel_ntb_reg skx_reg = {
-       .poll_link              = xeon_poll_link,
+       .poll_link              = skx_poll_link,
        .link_is_up             = xeon_link_is_up,
        .db_ioread              = skx_db_ioread,
        .db_iowrite             = skx_db_iowrite,