i40e: add hidden link status register dpdk driver is using

Not documented in the data sheet or the linux driver...

i40e_bm/base/i40e_register.h

@@ -5435,4 +5435,17 @@
 #define I40E_VFPE_WQEALLOC1_WQE_DESC_INDEX_SHIFT 20
 #define I40E_VFPE_WQEALLOC1_WQE_DESC_INDEX_MASK  I40E_MASK(0xFFF, I40E_VFPE_WQEALLOC1_WQE_DESC_INDEX_SHIFT)
 
+/* got these from i40e_ethdev.c in dpdk driver */
+#define I40E_PRTMAC_LINKSTA           0x001E2420
+#define I40E_REG_LINK_UP              0x40000080
+#define I40E_REG_SPEED_MASK           0x38000000
+#define I40E_REG_SPEED_100MB          0x00000000
+#define I40E_REG_SPEED_1GB            0x08000000
+#define I40E_REG_SPEED_10GB           0x10000000
+#define I40E_REG_SPEED_20GB           0x20000000
+#define I40E_REG_SPEED_25_40GB        0x18000000
+
+#define I40E_PRTMAC_MACC              0x001E24E0
+#define I40E_REG_MACC_25GB            0x00020000
+
 #endif /* _I40E_REGISTER_H_ */

i40e_bm/i40e_bm.cc

@@ -344,6 +344,14 @@ uint32_t i40e_bm::reg_mem_read32(uint64_t addr)
                 val = regs.pf_arqt;
                 break;
 
+            case I40E_PRTMAC_LINKSTA:
+                val = I40E_REG_LINK_UP | I40E_REG_SPEED_25_40GB;
+                break;
+
+            case I40E_PRTMAC_MACC:
+                val = 0;
+                break;
+
             default:
                 std::cerr << "unhandled mem read addr=" << std::hex << addr
                     << std::endl;