MIPS: BCM47xx: Add generic function filling SPROM entries

Handling many SPROM revisions became messy, we have tons of functions
specific to various revision groups which are quite hard to track.
For years there is yet another revision 11 asking for support, but
adding it in current the form would make things even worse.
To resolve this problem let's add new function with table-like entries
that will contain revision bitmask for every SPROM variable.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: Hauke Mehrtens <hauke@hauke-m.de>
Cc: Jonas Gorski <jonas.gorski@gmail.com>
Patchwork: https://patchwork.linux-mips.org/patch/9659/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/bcm47xx/sprom.c

@@ -180,6 +180,33 @@ static void nvram_read_alpha2(const char *prefix, const char *name,
 	memcpy(val, buf, 2);
 }
 
+/* This is one-function-only macro, it uses local "sprom" variable! */
+#define ENTRY(_revmask, _type, _prefix, _name, _val, _allset, _fallback) \
+	if (_revmask & BIT(sprom->revision)) \
+		nvram_read_ ## _type(_prefix, NULL, _name, &sprom->_val, \
+				     _allset, _fallback)
+/*
+ * Special version of filling function that can be safely called for any SPROM
+ * revision. For every NVRAM to SPROM mapping it contains bitmask of revisions
+ * for which the mapping is valid.
+ * It obviously requires some hexadecimal/bitmasks knowledge, but allows
+ * writing cleaner code (easy revisions handling).
+ * Note that while SPROM revision 0 was never used, we still keep BIT(0)
+ * reserved for it, just to keep numbering sane.
+ */
+static void bcm47xx_sprom_fill_auto(struct ssb_sprom *sprom,
+				    const char *prefix, bool fallback)
+{
+	const char *pre = prefix;
+	bool fb = fallback;
+
+	ENTRY(0xfffffffe, u16, pre, "boardrev", board_rev, 0, true);
+	ENTRY(0xfffffffe, u16, pre, "boardnum", board_num, 0, fb);
+
+	/* TODO: Move more mappings here */
+}
+#undef ENTRY /* It's specififc, uses local variable, don't use it (again). */
+
 static void bcm47xx_fill_sprom_r1234589(struct ssb_sprom *sprom,
 					const char *prefix, bool fallback)
 {
@@ -714,9 +741,6 @@ static void bcm47xx_fill_sprom_ethernet(struct ssb_sprom *sprom,
 static void bcm47xx_fill_board_data(struct ssb_sprom *sprom, const char *prefix,
 				    bool fallback)
 {
-	nvram_read_u16(prefix, NULL, "boardrev", &sprom->board_rev, 0, true);
-	nvram_read_u16(prefix, NULL, "boardnum", &sprom->board_num, 0,
-		       fallback);
 	nvram_read_u16(prefix, NULL, "boardtype", &sprom->board_type, 0, true);
 	nvram_read_u32_2(prefix, "boardflags", &sprom->boardflags_lo,
 			 &sprom->boardflags_hi, fallback);
@@ -787,6 +811,8 @@ void bcm47xx_fill_sprom(struct ssb_sprom *sprom, const char *prefix,
 		bcm47xx_fill_sprom_r12389(sprom, prefix, fallback);
 		bcm47xx_fill_sprom_r1(sprom, prefix, fallback);
 	}
+
+	bcm47xx_sprom_fill_auto(sprom, prefix, fallback);
 }
 
 #ifdef CONFIG_BCM47XX_SSB