NTB: Fix an error in get link status

The offset of PCIe Capability Header for AMD and HYGON NTB is 0x64,
but the macro which named "AMD_LINK_STATUS_OFFSET" is defined as 0x68.
It is offset of Device Capabilities Reg rather than Link Control Reg.

This code trigger an error in get link statsus:

	cat /sys/kernel/debug/ntb_hw_amd/0000:43:00.1/info
		LNK STA -               0x8fa1
		Link Status -           Up
		Link Speed -            PCI-E Gen 0
		Link Width -            x0

This patch use pcie_capability_read_dword to get link status.
After fix this issue, we can get link status accurately:

	cat /sys/kernel/debug/ntb_hw_amd/0000:43:00.1/info
		LNK STA -               0x11030042
		Link Status -           Up
		Link Speed -            PCI-E Gen 3
		Link Width -            x16

Fixes: a1b3695820aa4 ("NTB: Add support for AMD PCI-Express Non-Transparent Bridge")
Signed-off-by: Jiasen Lin <linjiasen@hygon.cn>
Signed-off-by: Jon Mason <jdmason@kudzu.us>

diff --git a/drivers/ntb/hw/amd/ntb_hw_amd.c b/drivers/ntb/hw/amd/ntb_hw_amd.c
index e52b300..ae91105 100644 (file)
--- a/drivers/ntb/hw/amd/ntb_hw_amd.c
+++ b/drivers/ntb/hw/amd/ntb_hw_amd.c
@@ -855,8 +855,8 @@ static int amd_poll_link(struct amd_ntb_dev *ndev)
 
        ndev->cntl_sta = reg;
 
-       rc = pci_read_config_dword(ndev->ntb.pdev,
-                                  AMD_LINK_STATUS_OFFSET, &stat);
+       rc = pcie_capability_read_dword(ndev->ntb.pdev,
+                                  PCI_EXP_LNKCTL, &stat);
        if (rc)
                return 0;
        ndev->lnk_sta = stat;

diff --git a/drivers/ntb/hw/amd/ntb_hw_amd.h b/drivers/ntb/hw/amd/ntb_hw_amd.h
index 139a307..39e5d18 100644 (file)
--- a/drivers/ntb/hw/amd/ntb_hw_amd.h
+++ b/drivers/ntb/hw/amd/ntb_hw_amd.h
@@ -53,7 +53,6 @@
 #include <linux/pci.h>
 
 #define AMD_LINK_HB_TIMEOUT    msecs_to_jiffies(1000)
-#define AMD_LINK_STATUS_OFFSET 0x68
 #define NTB_LIN_STA_ACTIVE_BIT 0x00000002
 #define NTB_LNK_STA_SPEED_MASK 0x000F0000
 #define NTB_LNK_STA_WIDTH_MASK 0x03F00000