diff --git a/drivers/mtd/maps/ck804xrom.c b/drivers/mtd/maps/ck804xrom.c
index 688ef495888a..59d8fb49270a 100644
--- a/drivers/mtd/maps/ck804xrom.c
+++ b/drivers/mtd/maps/ck804xrom.c
@@ -28,6 +28,9 @@
 
 #define ROM_PROBE_STEP_SIZE (64*1024)
 
+#define DEV_CK804 1
+#define DEV_MCP55 2
+
 struct ck804xrom_window {
 	void __iomem *virt;
 	unsigned long phys;
@@ -45,8 +48,9 @@ struct ck804xrom_map_info {
 	char map_name[sizeof(MOD_NAME) + 2 + ADDRESS_NAME_LEN];
 };
 
-
-/* The 2 bits controlling the window size are often set to allow reading
+/*
+ * The following applies to ck804 only:
+ * The 2 bits controlling the window size are often set to allow reading
  * the BIOS, but too small to allow writing, since the lock registers are
  * 4MiB lower in the address space than the data.
  *
@@ -58,10 +62,17 @@ struct ck804xrom_map_info {
  * If only the 7 Bit is set, it is a 4MiB window.  Otherwise, a
  * 64KiB window.
  *
+ * The following applies to mcp55 only:
+ * The 15 bits controlling the window size are distributed as follows: 
+ * byte @0x88: bit 0..7
+ * byte @0x8c: bit 8..15
+ * word @0x90: bit 16..30
+ * If all bits are enabled, we have a 16? MiB window
+ * Please set win_size_bits to 0x7fffffff if you actually want to do something
  */
 static uint win_size_bits = 0;
 module_param(win_size_bits, uint, 0);
-MODULE_PARM_DESC(win_size_bits, "ROM window size bits override for 0x88 byte, normally set by BIOS.");
+MODULE_PARM_DESC(win_size_bits, "ROM window size bits override, normally set by BIOS.");
 
 static struct ck804xrom_window ck804xrom_window = {
 	.maps = LIST_HEAD_INIT(ck804xrom_window.maps),
@@ -102,10 +113,11 @@ static void ck804xrom_cleanup(struct ck804xrom_window *window)
 
 
 static int __devinit ck804xrom_init_one (struct pci_dev *pdev,
-	const struct pci_device_id *ent)
+					 const struct pci_device_id *ent)
 {
 	static char *rom_probe_types[] = { "cfi_probe", "jedec_probe", NULL };
 	u8 byte;
+	u16 word;
 	struct ck804xrom_window *window = &ck804xrom_window;
 	struct ck804xrom_map_info *map = NULL;
 	unsigned long map_top;
@@ -113,26 +125,42 @@ static int __devinit ck804xrom_init_one (struct pci_dev *pdev,
 	/* Remember the pci dev I find the window in */
 	window->pdev = pci_dev_get(pdev);
 
-	/* Enable the selected rom window.  This is often incorrectly
-	 * set up by the BIOS, and the 4MiB offset for the lock registers
-	 * requires the full 5MiB of window space.
-	 *
-	 * This 'write, then read' approach leaves the bits for
-	 * other uses of the hardware info.
-	 */
-        pci_read_config_byte(pdev, 0x88, &byte);
-        pci_write_config_byte(pdev, 0x88, byte | win_size_bits );
+	switch (ent->driver_data) {
+	case DEV_CK804:
+		/* Enable the selected rom window.  This is often incorrectly
+		 * set up by the BIOS, and the 4MiB offset for the lock registers
+		 * requires the full 5MiB of window space.
+		 *
+		 * This 'write, then read' approach leaves the bits for
+		 * other uses of the hardware info.
+		 */
+		pci_read_config_byte(pdev, 0x88, &byte);
+		pci_write_config_byte(pdev, 0x88, byte | win_size_bits );
 
+		/* Assume the rom window is properly setup, and find it's size */
+		pci_read_config_byte(pdev, 0x88, &byte);
 
-	/* Assume the rom window is properly setup, and find it's size */
-	pci_read_config_byte(pdev, 0x88, &byte);
+		if ((byte & ((1<<7)|(1<<6))) == ((1<<7)|(1<<6)))
+			window->phys = 0xffb00000; /* 5MiB */
+		else if ((byte & (1<<7)) == (1<<7))
+			window->phys = 0xffc00000; /* 4MiB */
+		else
+			window->phys = 0xffff0000; /* 64KiB */
+		break;
 
-	if ((byte & ((1<<7)|(1<<6))) == ((1<<7)|(1<<6)))
-		window->phys = 0xffb00000; /* 5MiB */
-	else if ((byte & (1<<7)) == (1<<7))
-		window->phys = 0xffc00000; /* 4MiB */
-	else
-		window->phys = 0xffff0000; /* 64KiB */
+	case DEV_MCP55:
+		pci_read_config_byte(pdev, 0x88, &byte);
+		pci_write_config_byte(pdev, 0x88, byte | (win_size_bits & 0xff));
+
+		pci_read_config_byte(pdev, 0x8c, &byte);
+		pci_write_config_byte(pdev, 0x8c, byte | ((win_size_bits & 0xff00) >> 8));
+
+		pci_read_config_word(pdev, 0x90, &word);
+		pci_write_config_word(pdev, 0x90, word | ((win_size_bits & 0x7fff0000) >> 16));
+
+		window->phys = 0xff000000; /* 16MiB, hardcoded for now */
+		break;
+	}
 
 	window->size = 0xffffffffUL - window->phys + 1UL;
 
@@ -303,8 +331,15 @@ static void __devexit ck804xrom_remove_one (struct pci_dev *pdev)
 }
 
 static struct pci_device_id ck804xrom_pci_tbl[] = {
-	{ PCI_VENDOR_ID_NVIDIA, 0x0051,
-        PCI_ANY_ID, PCI_ANY_ID, }, /* nvidia ck804 */
+	{ PCI_VENDOR_ID_NVIDIA, 0x0051, PCI_ANY_ID, PCI_ANY_ID, DEV_CK804 },
+	{ PCI_VENDOR_ID_NVIDIA, 0x0360, PCI_ANY_ID, PCI_ANY_ID, DEV_MCP55 },
+	{ PCI_VENDOR_ID_NVIDIA, 0x0361, PCI_ANY_ID, PCI_ANY_ID, DEV_MCP55 },
+	{ PCI_VENDOR_ID_NVIDIA, 0x0362, PCI_ANY_ID, PCI_ANY_ID, DEV_MCP55 },
+	{ PCI_VENDOR_ID_NVIDIA, 0x0363, PCI_ANY_ID, PCI_ANY_ID, DEV_MCP55 },
+	{ PCI_VENDOR_ID_NVIDIA, 0x0364, PCI_ANY_ID, PCI_ANY_ID, DEV_MCP55 },
+	{ PCI_VENDOR_ID_NVIDIA, 0x0365, PCI_ANY_ID, PCI_ANY_ID, DEV_MCP55 },
+	{ PCI_VENDOR_ID_NVIDIA, 0x0366, PCI_ANY_ID, PCI_ANY_ID, DEV_MCP55 },
+	{ PCI_VENDOR_ID_NVIDIA, 0x0367, PCI_ANY_ID, PCI_ANY_ID, DEV_MCP55 },
 	{ 0, }
 };
 
@@ -332,7 +367,7 @@ static int __init init_ck804xrom(void)
 			break;
 	}
 	if (pdev) {
-		retVal = ck804xrom_init_one(pdev, &ck804xrom_pci_tbl[0]);
+		retVal = ck804xrom_init_one(pdev, id);
 		pci_dev_put(pdev);
 		return retVal;
 	}