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-rw-r--r--chipset_enable.c47
1 files changed, 27 insertions, 20 deletions
diff --git a/chipset_enable.c b/chipset_enable.c
index 39e59dd..995d2c5 100644
--- a/chipset_enable.c
+++ b/chipset_enable.c
@@ -281,22 +281,15 @@ static int enable_flash_piix4(struct pci_dev *dev, const char *name)
* See ie. page 375 of "Intel I/O Controller Hub 7 (ICH7) Family Datasheet"
* http://download.intel.com/design/chipsets/datashts/30701303.pdf
*/
-static int enable_flash_ich(struct pci_dev *dev, const char *name,
- int bios_cntl)
+static int enable_flash_ich(struct pci_dev *dev, const char *name, uint8_t bios_cntl)
{
uint8_t old, new, wanted;
/*
- * Note: the ICH0-ICH5 BIOS_CNTL register is actually 16 bit wide, but
+ * Note: the ICH0-ICH5 BIOS_CNTL register is actually 16 bit wide, in Tunnel Creek it is even 32b, but
* just treating it as 8 bit wide seems to work fine in practice.
*/
- old = pci_read_byte(dev, bios_cntl);
-
- msg_pdbg("\nBIOS Lock Enable: %sabled, ",
- (old & (1 << 1)) ? "en" : "dis");
- msg_pdbg("BIOS Write Enable: %sabled, ",
- (old & (1 << 0)) ? "en" : "dis");
- msg_pdbg("BIOS_CNTL is 0x%x\n", old);
+ wanted = old = pci_read_byte(dev, bios_cntl);
/*
* Quote from the 6 Series datasheet (Document Number: 324645-004):
@@ -304,22 +297,36 @@ static int enable_flash_ich(struct pci_dev *dev, const char *name,
* 1 = BIOS region SMM protection is enabled.
* The BIOS Region is not writable unless all processors are in SMM."
* In earlier chipsets this bit is reserved.
+ *
+ * Try to unset it in any case.
+ * It won't hurt and makes sense in some cases according to Stefan Reinauer.
*/
- if (old & (1 << 5))
+ wanted &= ~(1 << 5);
+
+ /* Set BIOS Write Enable */
+ wanted |= (1 << 0);
+
+ /* Only write the register if it's necessary */
+ if (wanted != old) {
+ rpci_write_byte(dev, bios_cntl, wanted);
+ new = pci_read_byte(dev, bios_cntl);
+ } else
+ new = old;
+
+ msg_pdbg("\nBIOS_CNTL = 0x%02x: ", new);
+ msg_pdbg("BIOS Lock Enable: %sabled, ", (new & (1 << 1)) ? "en" : "dis");
+ msg_pdbg("BIOS Write Enable: %sabled\n", (new & (1 << 0)) ? "en" : "dis");
+ if (new & (1 << 5))
msg_pinfo("WARNING: BIOS region SMM protection is enabled!\n");
- wanted = old | 1;
- if (wanted == old)
- return 0;
- rpci_write_byte(dev, bios_cntl, wanted);
+ if (new != wanted)
+ msg_pinfo("WARNING: Setting Bios Control at 0x%x from 0x%02x to 0x%02x on %s failed.\n"
+ "New value is 0x%02x.\n", bios_cntl, old, wanted, name, new);
- if ((new = pci_read_byte(dev, bios_cntl)) != wanted) {
- msg_pinfo("WARNING: Setting 0x%x from 0x%x to 0x%x on %s "
- "failed. New value is 0x%x.\n",
- bios_cntl, old, wanted, name, new);
+ /* Return an error if we could not set the write enable */
+ if (!(new & (1 << 0)))
return -1;
- }
return 0;
}
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