net: mvpp2: prs: Drop unions representing TCAM and SRAM entries

PPv2's Header Parser use some large TCAM and SRAM entries, that are
duplicated in software so that we can write them to hardware only when
we are done modifying them.

Currently, PPv2 uses a union containing arrays of u32 and u8 to represent
these entries, to facilitate byte per byte access. This representation is
broken when we want to support big endian, and this makes the code
confusing to read.

This patch drops the union, and simply stores the TCAM and SRAM entries
as u32 arrays, each entry corresponding to a 32-bit register.
Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/marvell/mvpp2/mvpp2.h

@@ -553,6 +553,8 @@
 	((total_size) - NET_SKB_PAD - MVPP2_SKB_SHINFO_SIZE)
 
 #define MVPP2_BIT_TO_BYTE(bit)		((bit) / 8)
+#define MVPP2_BIT_TO_WORD(bit)		((bit) / 32)
+#define MVPP2_BIT_IN_WORD(bit)		((bit) % 32)
 
 /* IPv6 max L3 address size */
 #define MVPP2_MAX_L3_ADDR_SIZE		16

drivers/net/ethernet/marvell/mvpp2/mvpp2_prs.h

@@ -50,17 +50,25 @@
  * The fields are represented by MVPP2_PRS_TCAM_DATA_REG(5)->(0).
  */
 #define MVPP2_PRS_AI_BITS			8
+#define MVPP2_PRS_AI_MASK			0xff
 #define MVPP2_PRS_PORT_MASK			0xff
 #define MVPP2_PRS_LU_MASK			0xf
-#define MVPP2_PRS_TCAM_DATA_BYTE(offs)		\
-				    (((offs) - ((offs) % 2)) * 2 + ((offs) % 2))
-#define MVPP2_PRS_TCAM_DATA_BYTE_EN(offs)	\
-					      (((offs) * 2) - ((offs) % 2)  + 2)
-#define MVPP2_PRS_TCAM_AI_BYTE			16
-#define MVPP2_PRS_TCAM_PORT_BYTE		17
-#define MVPP2_PRS_TCAM_LU_BYTE			20
-#define MVPP2_PRS_TCAM_EN_OFFS(offs)		((offs) + 2)
-#define MVPP2_PRS_TCAM_INV_WORD			5
+
+/* TCAM entries in registers are accessed using 16 data bits + 16 enable bits */
+#define MVPP2_PRS_BYTE_TO_WORD(byte)	((byte) / 2)
+#define MVPP2_PRS_BYTE_IN_WORD(byte)	((byte) % 2)
+
+#define MVPP2_PRS_TCAM_EN(data)		((data) << 16)
+#define MVPP2_PRS_TCAM_AI_WORD		4
+#define MVPP2_PRS_TCAM_AI(ai)		(ai)
+#define MVPP2_PRS_TCAM_AI_EN(ai)	MVPP2_PRS_TCAM_EN(MVPP2_PRS_TCAM_AI(ai))
+#define MVPP2_PRS_TCAM_PORT_WORD	4
+#define MVPP2_PRS_TCAM_PORT(p)		((p) << 8)
+#define MVPP2_PRS_TCAM_PORT_EN(p)	MVPP2_PRS_TCAM_EN(MVPP2_PRS_TCAM_PORT(p))
+#define MVPP2_PRS_TCAM_LU_WORD		5
+#define MVPP2_PRS_TCAM_LU(lu)		(lu)
+#define MVPP2_PRS_TCAM_LU_EN(lu)	MVPP2_PRS_TCAM_EN(MVPP2_PRS_TCAM_LU(lu))
+#define MVPP2_PRS_TCAM_INV_WORD		5
 
 #define MVPP2_PRS_VID_TCAM_BYTE         2
 
@@ -146,6 +154,7 @@
 #define MVPP2_PRS_SRAM_RI_CTRL_BITS		32
 #define MVPP2_PRS_SRAM_SHIFT_OFFS		64
 #define MVPP2_PRS_SRAM_SHIFT_SIGN_BIT		72
+#define MVPP2_PRS_SRAM_SHIFT_MASK		0xff
 #define MVPP2_PRS_SRAM_UDF_OFFS			73
 #define MVPP2_PRS_SRAM_UDF_BITS			8
 #define MVPP2_PRS_SRAM_UDF_MASK			0xff
@@ -255,20 +264,10 @@ enum mvpp2_prs_lookup {
 	MVPP2_PRS_LU_LAST,
 };
 
-union mvpp2_prs_tcam_entry {
-	u32 word[MVPP2_PRS_TCAM_WORDS];
-	u8  byte[MVPP2_PRS_TCAM_WORDS * 4];
-};
-
-union mvpp2_prs_sram_entry {
-	u32 word[MVPP2_PRS_SRAM_WORDS];
-	u8  byte[MVPP2_PRS_SRAM_WORDS * 4];
-};
-
 struct mvpp2_prs_entry {
 	u32 index;
-	union mvpp2_prs_tcam_entry tcam;
-	union mvpp2_prs_sram_entry sram;
+	u32 tcam[MVPP2_PRS_TCAM_WORDS];
+	u32 sram[MVPP2_PRS_SRAM_WORDS];
 };
 
 struct mvpp2_prs_shadow {