Fix wrong VT8235 flash enable failed warning

* Fix harmless but worrying warning where the return value of
  pci_write_byte is misinterpreted.
* Hash together VT8231 and VT8235 code into VT823x. VT8231 is the better
  implementation, but lacked the write protect disable code that's
  apparently needed for VT8235.

Corresponding to flashrom svn r93 and coreboot v2 svn r2568.
Signed-off-by: Luc Verhaegen <libv@skynet.be>
Signed-off-by: Uwe Hermann <uwe@hermann-uwe.de>
Acked-by: Stefan Reinauer <stepan@coresystems.de>

flash_enable.c

@@ -158,52 +158,49 @@ static int enable_flash_ich_dc(struct pci_dev *dev, char *name)
 	return enable_flash_ich(dev, name, 0xdc);
 }
 
-static int enable_flash_vt8235(struct pci_dev *dev, char *name)
-{
-	uint8_t old, new, val;
-	unsigned int base;
-	int ok;
-
-	old = pci_read_byte(dev, 0x40);
-
-	new = old | 0x10;
-
-	if (new == old)
-		return 0;
-
-	ok = pci_write_byte(dev, 0x40, new);
-	if (ok != 0) {
-		printf("tried to set 0x%x to 0x%x on %s failed (WARNING ONLY)\n",
-		       old, new, name);
-	}
-
-	/* enable GPIO15 which is connected to write protect. */
-	base = ((pci_read_byte(dev, 0x88) & 0x80) | pci_read_byte(dev, 0x89) << 8);
-	val = inb(base + 0x4d);
-	val |= 0x80;
-	outb(val, base + 0x4d);
-
-	if (ok != 0) {
-		return -1;
-	} else {
-		return 0;
-	}
-}
-
-static int enable_flash_vt8231(struct pci_dev *dev, char *name)
+static int enable_flash_vt823x(struct pci_dev *dev, char *name)
 {
 	uint8_t val;
+        int ret = 0;
 
+        /* ROM Write enable */
 	val = pci_read_byte(dev, 0x40);
 	val |= 0x10;
 	pci_write_byte(dev, 0x40, val);
 
 	if (pci_read_byte(dev, 0x40) != val) {
-		printf("tried to set 0x%x to 0x%x on %s failed (WARNING ONLY)\n",
-		       0x40, val, name);
-		return -1;
+		printf("Warning: Failed to enable ROM Write on %s\n", name);
+		ret = -1;
 	}
-	return 0;
+
+        if (dev->device_id == 0x3177) { /* VT8235 */
+                if (!iopl(3)) { /* enable full IO access */
+                        unsigned int base;
+
+                        /* GPIO12-15 -> output */
+                        val = pci_read_byte(dev, 0xE4);
+                        val |= 0x38;
+                        pci_write_byte(dev, 0xE4, val);
+
+                        /* Get Power Management IO address. */
+                        base = pci_read_word(dev, 0x88) & 0xFF80;
+
+                        /* enable GPIO15 which is connected to write protect. */
+                        val = inb(base + 0x4d);
+                        val |= 0xFF;
+                        outb(val, base + 0x4d);
+
+                        val = inb(base + 0x4E);
+                        val |= 0x0F;
+                        outb(val, base + 0x4E);
+                } else {
+                        printf("Warning; Failed to disable Write Protect"
+                               " on %s (iopl failed)\n", name);
+                        return -1;
+                }
+        }
+
+	return ret;
 }
 
 static int enable_flash_cs5530(struct pci_dev *dev, char *name)
@@ -445,9 +442,9 @@ static FLASH_ENABLE enables[] = {
 	{0x8086, 0x2810, "ICH8/ICH8R", enable_flash_ich_dc},
 	{0x8086, 0x2812, "ICH8DH", enable_flash_ich_dc},
 	{0x8086, 0x2814, "ICH8DO", enable_flash_ich_dc},
-	{0x1106, 0x8231, "VT8231", enable_flash_vt8231},
-	{0x1106, 0x3177, "VT8235", enable_flash_vt8235},
-	{0x1106, 0x3227, "VT8237", enable_flash_vt8231},
+	{0x1106, 0x8231, "VT8231", enable_flash_vt823x},
+	{0x1106, 0x3177, "VT8235", enable_flash_vt823x},
+	{0x1106, 0x3227, "VT8237", enable_flash_vt823x},
 	{0x1106, 0x0686, "VT82C686", enable_flash_amd8111},
 	{0x1078, 0x0100, "CS5530", enable_flash_cs5530},
 	{0x100b, 0x0510, "SC1100", enable_flash_sc1100},