firewire: sbp2: define some magic numbers as macros

Signed-off-by: Stefan Richter <[e-mail]>

drivers/firewire/fw-sbp2.c

···
 	dma_addr_t page_table_bus;
 };
 
+#define SBP2_ROM_VALUE_WILDCARD ~0         /* match all */
+#define SBP2_ROM_VALUE_MISSING  0xff000000 /* not present in the unit dir. */
+
 /*
  * List of devices with known bugs.
  *
  * The firmware_revision field, masked with 0xffff00, is the best
  * indicator for the type of bridge chip of a device.  It yields a few
  * false positives but this did not break correctly behaving devices
- * so far.  We use ~0 as a wildcard, since the 24 bit values we get
- * from the config rom can never match that.
+ * so far.
  */
 static const struct {
 	u32 firmware_revision;
···
 	},
 	/* Initio bridges, actually only needed for some older ones */ {
 		.firmware_revision	= 0x000200,
-		.model			= ~0,
+		.model			= SBP2_ROM_VALUE_WILDCARD,
 		.workarounds		= SBP2_WORKAROUND_INQUIRY_36,
 	},
 	/* PL-3507 bridge with Prolific firmware */ {
 		.firmware_revision	= 0x012800,
-		.model			= ~0,
+		.model			= SBP2_ROM_VALUE_WILDCARD,
 		.workarounds		= SBP2_WORKAROUND_POWER_CONDITION,
 	},
 	/* Symbios bridge */ {
 		.firmware_revision	= 0xa0b800,
-		.model			= ~0,
+		.model			= SBP2_ROM_VALUE_WILDCARD,
 		.workarounds		= SBP2_WORKAROUND_128K_MAX_TRANS,
 	},
 	/* Datafab MD2-FW2 with Symbios/LSILogic SYM13FW500 bridge */ {
 		.firmware_revision	= 0x002600,
-		.model			= ~0,
+		.model			= SBP2_ROM_VALUE_WILDCARD,
 		.workarounds		= SBP2_WORKAROUND_128K_MAX_TRANS,
 	},
 
···
 			continue;
 
 		if (sbp2_workarounds_table[i].model != model &&
-		    sbp2_workarounds_table[i].model != ~0)
+		    sbp2_workarounds_table[i].model != SBP2_ROM_VALUE_WILDCARD)
 			continue;
 
 		w |= sbp2_workarounds_table[i].workarounds;
···
 	fw_device_get(device);
 	fw_unit_get(unit);
 
-	/* Initialize to values that won't match anything in our table. */
-	firmware_revision = 0xff000000;
-	model = 0xff000000;
-
 	/* implicit directory ID */
 	tgt->directory_id = ((unit->directory - device->config_rom) * 4
 			     + CSR_CONFIG_ROM) & 0xffffff;
+
+	firmware_revision = SBP2_ROM_VALUE_MISSING;
+	model		  = SBP2_ROM_VALUE_MISSING;
 
 	if (sbp2_scan_unit_dir(tgt, unit->directory, &model,
 			       &firmware_revision) < 0)