cxgb4: Fixed the code to use correct length for part number

Previously it was using the length value of serial number.
Also added macro for VPD unique identifier (0x82).
Signed-off-by: NCasey Leedom <leedom@chelsio.com>
Signed-off-by: NHariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/chelsio/cxgb4/t4_hw.c

@@ -566,6 +566,7 @@ int t4_memory_rw(struct adapter *adap, int win, int mtype, u32 addr,
 #define VPD_BASE           0x400
 #define VPD_BASE_OLD       0
 #define VPD_LEN            1024
+#define CHELSIO_VPD_UNIQUE_ID 0x82
 
 /**
  *	t4_seeprom_wp - enable/disable EEPROM write protection
@@ -603,7 +604,14 @@ int get_vpd_params(struct adapter *adapter, struct vpd_params *p)
 	ret = pci_read_vpd(adapter->pdev, VPD_BASE, sizeof(u32), vpd);
 	if (ret < 0)
 		goto out;
-	addr = *vpd == 0x82 ? VPD_BASE : VPD_BASE_OLD;
+
+	/* The VPD shall have a unique identifier specified by the PCI SIG.
+	 * For chelsio adapters, the identifier is 0x82. The first byte of a VPD
+	 * shall be CHELSIO_VPD_UNIQUE_ID (0x82). The VPD programming software
+	 * is expected to automatically put this entry at the
+	 * beginning of the VPD.
+	 */
+	addr = *vpd == CHELSIO_VPD_UNIQUE_ID ? VPD_BASE : VPD_BASE_OLD;
 
 	ret = pci_read_vpd(adapter->pdev, addr, VPD_LEN, vpd);
 	if (ret < 0)
@@ -667,6 +675,7 @@ int get_vpd_params(struct adapter *adapter, struct vpd_params *p)
 	i = pci_vpd_info_field_size(vpd + sn - PCI_VPD_INFO_FLD_HDR_SIZE);
 	memcpy(p->sn, vpd + sn, min(i, SERNUM_LEN));
 	strim(p->sn);
+	i = pci_vpd_info_field_size(vpd + pn - PCI_VPD_INFO_FLD_HDR_SIZE);
 	memcpy(p->pn, vpd + pn, min(i, PN_LEN));
 	strim(p->pn);