[flashrom] [PATCH 1/2] Nvidia CK804 enable improvement

[Stefan Tauner]

Ensure all read and write locks are disabled on ck804 (and MCP51).

Currently the same chipset enable is used for MCP51 (nForce 430) too.
There have been reports of successful writes with its variations
(e.g. A8N-LA (Nagami-GL8E)), but the chipset enables were not tagged as OK.
Due to the new "unsupported chipset"-message we will get success reports in
the case this patch does not break anything on the MCP51-based boards.

Tested on CK804 and
Signed-off-by: Jonathan Kollasch <jakllsch at kollasch.net>
which was previously
Acked-by: Stefan Reinauer <stepan at coreboot.org>

Rebasing, rephrasing and making errors non-fatal is
Signed-off-by: Stefan Tauner <stefan.tauner at student.tuwien.ac.at>
---
 chipset_enable.c |   50 ++++++++++++++++++++++++++++++++++++++++++++++----
 1 files changed, 46 insertions(+), 4 deletions(-)

diff --git a/chipset_enable.c b/chipset_enable.c
index 97001a7..294007d 100644
--- a/chipset_enable.c
+++ b/chipset_enable.c
@@ -799,14 +799,56 @@ static int enable_flash_nvidia_nforce2(struct pci_dev *dev, const char *name)
 
 static int enable_flash_ck804(struct pci_dev *dev, const char *name)
 {
+	uint32_t segctrl;
+	int segreg;
 	uint8_t old, new;
 
-	pci_write_byte(dev, 0x92, 0x00);
-	if (pci_read_byte(dev, 0x92) != 0x00) {
-		msg_pinfo("Setting register 0x%x to 0x%x on %s failed "
-			  "(WARNING ONLY).\n", 0x92, 0x00, name);
+	for (segreg = 0x8c; segreg < 0x98; segreg += 4) {
+		segctrl = pci_read_long(dev, segreg);
+		if ((segctrl & 0x33333333) != 0x00000000) {
+			/* reads or writes are locked */
+			if ((segctrl & 0xCCCCCCCC) == 0x00000000) {
+				/* we can unlock */
+				msg_pdbg("Unlocking in 0x%02x.\n", segreg);
+				pci_write_long(dev, segreg, 0x00000000);
+			} else {
+				msg_pinfo("Can't unlock in 0x%02x, disabling "
+					  "writes (reads may also fail).\n",
+					  segreg);
+				programmer_may_write = 0;
+				goto ck804_lockbits_done;
+			}
+		}
+		segctrl = pci_read_long(dev, segreg);
+		if ((segctrl & 0x33333333) != 0x00000000) {
+			msg_pinfo("Still locked in 0x%02x (0x%08x), disabling "
+				  "writes (reads may also fail).\n",
+				  segreg, segctrl);
+			programmer_may_write = 0;
+			goto ck804_lockbits_done;
+		}
+	}
+	segctrl = pci_read_byte(dev, 0x8a);
+	if ((segctrl & 0x3) != 0x0) {
+		if ((segctrl & 0xc) == 0x0) {
+			msg_pdbg("Unlocking in 0x%02x\n", 0x8a);
+			pci_write_byte(dev, 0x8a, segctrl & 0xf0);
+		} else {
+			msg_pinfo("Can't unlock in 0x%02x, disabling writes "
+				  "(reads may also fail).\n", 0x8a);
+			programmer_may_write = 0;
+			goto ck804_lockbits_done;
+		}
+	}
+	segctrl = pci_read_byte(dev, 0x8a);
+	if ((segctrl & 0x3) != 0x0) {
+		msg_pinfo("Still locked in 0x%02x (0x%08x), disabling "
+			  "writes (reads may also fail).\n", segreg, segctrl);
+		programmer_may_write = 0;
+		goto ck804_lockbits_done;
 	}
 
+ck804_lockbits_done:
 	old = pci_read_byte(dev, 0x88);
 	new = old | 0xc0;
 	if (new != old) {
-- 
1.7.1