fsl/fman: fix parser reporting bad checksum on short frames

The FMan hardware parser needs to be configured to remove the
short frame padding from the checksum calculation, otherwise
short UDP and TCP frames are likely to be marked as having a
bad checksum.
Signed-off-by: Madalin Bucur <madalin.bucur@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/freescale/fman/fman_port.c

@@ -324,6 +324,10 @@ struct fman_port_qmi_regs {
 #define HWP_HXS_PHE_REPORT 0x00000800
 #define HWP_HXS_PCAC_PSTAT 0x00000100
 #define HWP_HXS_PCAC_PSTOP 0x00000001
+#define HWP_HXS_TCP_OFFSET 0xA
+#define HWP_HXS_UDP_OFFSET 0xB
+#define HWP_HXS_SH_PAD_REM 0x80000000
+
 struct fman_port_hwp_regs {
 	struct {
 		u32 ssa; /* Soft Sequence Attachment */
@@ -728,6 +732,10 @@ static void init_hwp(struct fman_port *port)
 		iowrite32be(0xffffffff, &regs->pmda[i].lcv);
 	}
 
+	/* Short packet padding removal from checksum calculation */
+	iowrite32be(HWP_HXS_SH_PAD_REM, &regs->pmda[HWP_HXS_TCP_OFFSET].ssa);
+	iowrite32be(HWP_HXS_SH_PAD_REM, &regs->pmda[HWP_HXS_UDP_OFFSET].ssa);
+
 	start_port_hwp(port);
 }