net: mscc: improve the frame header parsing readability

This cosmetic patch improves the frame header parsing readability by
introducing a new macro to access and mask its fields.

Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/mscc/ocelot_board.c b/drivers/net/ethernet/mscc/ocelot_board.c
index 990027f04d1bba2bc6a856f2b76daef7901ce782..5e4f1718dd9930a51014eeaa6029cc1a4d544f3e 100644 (file)
--- a/drivers/net/ethernet/mscc/ocelot_board.c
+++ b/drivers/net/ethernet/mscc/ocelot_board.c
@@ -16,24 +16,26 @@
 
 #include "ocelot.h"
 
-static int ocelot_parse_ifh(u32 *ifh, struct frame_info *info)
+#define IFH_EXTRACT_BITFIELD64(x, o, w) (((x) >> (o)) & GENMASK_ULL((w) - 1, 0))
+
+static int ocelot_parse_ifh(u32 *_ifh, struct frame_info *info)
 {
-       int i;
        u8 llen, wlen;
+       u64 ifh[2];
+
+       ifh[0] = be64_to_cpu(((__force __be64 *)_ifh)[0]);
+       ifh[1] = be64_to_cpu(((__force __be64 *)_ifh)[1]);
 
-       /* The IFH is in network order, switch to CPU order */
-       for (i = 0; i < IFH_LEN; i++)
-               ifh[i] = ntohl((__force __be32)ifh[i]);
+       wlen = IFH_EXTRACT_BITFIELD64(ifh[0], 7,  8);
+       llen = IFH_EXTRACT_BITFIELD64(ifh[0], 15,  6);
 
-       wlen = (ifh[1] >> 7) & 0xff;
-       llen = (ifh[1] >> 15) & 0x3f;
        info->len = OCELOT_BUFFER_CELL_SZ * wlen + llen - 80;
 
-       info->port = (ifh[2] & GENMASK(14, 11)) >> 11;
+       info->port = IFH_EXTRACT_BITFIELD64(ifh[1], 43, 4);
 
-       info->cpuq = (ifh[3] & GENMASK(27, 20)) >> 20;
-       info->tag_type = (ifh[3] & BIT(16)) >> 16;
-       info->vid = ifh[3] & GENMASK(11, 0);
+       info->cpuq = IFH_EXTRACT_BITFIELD64(ifh[1], 20, 8);
+       info->tag_type = IFH_EXTRACT_BITFIELD64(ifh[1], 16,  1);
+       info->vid = IFH_EXTRACT_BITFIELD64(ifh[1], 0,  12);
 
        return 0;
 }