Add SPI mode diagnostics for all post-MCP55 (nForce 5) chipsets from Nvidia

Huge thanks to Michael Karcher for reverse engineering the MCP67 chipset
and writing a spec. Due to this, we were able to use the chinese wall
technique for 100% clean room reverse engineering.

This patch doesn't touch any of the new registers, it only reads them.
Assuming that read has no side effects, this patch is a no-op and safe.

We need "flashrom -V" output from all post-MCP55 (nForce 5) chipset
boards. Please indicate if your board uses SPI flash or LPC flash (if
you know it). Note: That output is only helpful if it is created with
patched flashrom and if is from the first run of flashrom after a cold
boot (reset or Ctrl-Alt-Del is not sufficient). There is a pattern based
on which we can probably detect which flash type is present on the
board.

Thanks to Alessandro Polverini for testing earlier iterations of this
patch.

Note: The MCP67 should work. I guessed that the other recent Nvidia
chipsets would work in a similar way, and created a simplified
do-nothing catchall chipset enable function which dumps some info and
instructs the user to send more info.

Corresponding to flashrom svn r902.

Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
Acked-by: Michael Karcher <flashrom@mkarcher.dialup.fu-berlin.de>

chipset_enable.c

@@ -1054,6 +1054,127 @@ static int enable_flash_mcp55(struct pci_dev *dev, const char *name)
 	return 0;
 }
 
+/**
+ * The MCP67 code is guesswork based on cleanroom reverse engineering.
+ * Due to that, it only reads info and doesn't change any settings.
+ * It is assumed that LPC chips need the MCP55 code and SPI chips need the
+ * code provided in this function. Until we know for sure, call
+ * enable_flash_mcp55 from this function. Warning: enable_flash_mcp55
+ * might make SPI flash inaccessible. The same caveat applies to SPI init
+ * for LPC flash.
+ */
+static int enable_flash_mcp67(struct pci_dev *dev, const char *name)
+{
+	int result = 0;
+	uint8_t byte;
+	uint16_t status;
+	uint32_t mcp_spibaraddr;
+	void *mcp_spibar;
+	struct pci_dev *smbusdev;
+
+	/* dev is the ISA bridge. No idea what the stuff below does. */
+	byte = pci_read_byte(dev, 0x8a);
+	msg_pdbg("ISA bridge reg 0x8a contents: 0x%02x, bit 6 is %i, bit 5 is "
+		 "%i\n", byte, (byte >> 6) & 0x1, (byte >> 5) & 0x1);
+	msg_pdbg("Guessed flash bus type is %s\n", ((byte >> 5) & 0x3) == 0x2 ?
+		 "SPI" : "unknown, probably LPC");
+	/* Disable the write code for now until we have more info. */
+#if 0
+	byte |= (1 << 6);
+	byte &= ~(1 << 5);
+	pci_write_byte(dev, 0x8a, byte);
+#endif
+
+	/* Look for the SMBus device (SMBus PCI class) */
+	smbusdev = pci_dev_find_vendorclass(0x10de, 0x0c05);
+	if (!smbusdev) {
+		msg_perr("ERROR: SMBus device not found. Aborting.\n");
+		exit(1);
+	}
+	msg_pdbg("Found SMBus device %04x:%04x at %02x:%02x:%01x\n",
+		smbusdev->vendor_id, smbusdev->device_id,
+		smbusdev->bus, smbusdev->dev, smbusdev->func);
+
+	/* Locate the BAR where the SPI interface lives. */
+	mcp_spibaraddr = pci_read_long(smbusdev, 0x74);
+	msg_pdbg("SPI BAR is at 0x%08x, ", mcp_spibaraddr);
+	/* We hope this has native alignment. We know the SPI interface (well,
+	 * a set of GPIOs that is connected to SPI flash) is at offset 0x530,
+	 * so we expect a size of at least 0x800. Clear the lower bits.
+	 * It is entirely possible that the BAR is 64k big and the low bits are
+	 * reserved for an entirely different purpose.
+	 */
+	mcp_spibaraddr &= ~0x7ff;
+	msg_pdbg("after clearing low bits BAR is at 0x%08x\n", mcp_spibaraddr);
+
+	/* Accessing a NULL pointer BAR is evil. Don't do it. */
+	if (mcp_spibaraddr) {
+		/* Map the BAR. Bytewise/wordwise access at 0x530 and 0x540. */
+		mcp_spibar = physmap("MCP67 SPI", mcp_spibaraddr, 0x544);
+
+/* Guessed. If this is correct, migrate to a separate MCP67 SPI driver. */
+#define MCP67_SPI_CS		(1 << 1)
+#define MCP67_SPI_SCK		(1 << 2)
+#define MCP67_SPI_MOSI		(1 << 3)
+#define MCP67_SPI_MISO		(1 << 4)
+#define MCP67_SPI_ENABLE	(1 << 0)
+#define MCP67_SPI_IDLE		(1 << 8)
+
+		status = mmio_readw(mcp_spibar + 0x530);
+		msg_pdbg("SPI control is 0x%04x, enable=%i, idle=%i\n",
+			 status, status & 0x1, (status >> 8) & 0x1);
+		/* FIXME: Remove the physunmap once the SPI driver exists. */
+		physunmap(mcp_spibar, 0x544);
+	} else {
+		msg_pdbg("Strange. MCP67 SPI BAR is invalid.\n");
+	}
+	msg_pinfo("Please send the output of \"flashrom -V\" to "
+		  "flashrom@flashrom.org to help us finish support for your "
+		  "chipset. Thanks.\n");
+
+	/* Not sure if this is still correct. No docs as usual. */
+	result = enable_flash_mcp55(dev, name);
+
+	return result;
+}
+
+/* This is a shot in the dark. Even if the code is totally bogus for some
+ * chipsets, users will at least start to send in reports.
+ */
+static int enable_flash_mcp7x(struct pci_dev *dev, const char *name)
+{
+	uint8_t byte;
+	uint32_t mcp_spibaraddr;
+	struct pci_dev *smbusdev;
+
+	msg_pinfo("This chipset is not really supported yet. Guesswork...\n");
+
+	/* dev is the ISA bridge. No idea what the stuff below does. */
+	byte = pci_read_byte(dev, 0x8a);
+	msg_pdbg("ISA/LPC bridge reg 0x8a contents: 0x%02x, bit 6 is %i, bit 5 "
+		 "is %i\n", byte, (byte >> 6) & 0x1, (byte >> 5) & 0x1);
+
+	/* Look for the SMBus device (SMBus PCI class) */
+	smbusdev = pci_dev_find_vendorclass(0x10de, 0x0c05);
+	if (!smbusdev) {
+		msg_perr("ERROR: SMBus device not found. Aborting.\n");
+		exit(1);
+	}
+	msg_pdbg("Found SMBus device %04x:%04x at %02x:%02x:%01x\n",
+		smbusdev->vendor_id, smbusdev->device_id,
+		smbusdev->bus, smbusdev->dev, smbusdev->func);
+
+	/* Locate the BAR where the SPI interface lives. */
+	mcp_spibaraddr = pci_read_long(smbusdev, 0x74);
+	msg_pdbg("SPI BAR is at 0x%08x, ", mcp_spibaraddr);
+
+	msg_pinfo("Please send the output of \"flashrom -V\" to "
+		  "flashrom@flashrom.org to help us finish support for your "
+		  "chipset. Thanks.\n");
+
+	return 0;
+}
+
 static int enable_flash_ht1000(struct pci_dev *dev, const char *name)
 {
 	uint8_t byte;
@@ -1193,7 +1314,22 @@ const struct penable chipset_enables[] = {
 	{0x10de, 0x0365, OK, "NVIDIA", "MCP55",		enable_flash_mcp55}, /* LPC */
 	{0x10de, 0x0366, OK, "NVIDIA", "MCP55",		enable_flash_mcp55}, /* LPC */
 	{0x10de, 0x0367, OK, "NVIDIA", "MCP55",		enable_flash_mcp55}, /* Pro */
-	{0x10de, 0x0548, OK, "NVIDIA", "MCP67",		enable_flash_mcp55},
+	{0x10de, 0x03e0, NT, "NVIDIA", "MCP61",		enable_flash_mcp7x},
+	{0x10de, 0x03e1, NT, "NVIDIA", "MCP61",		enable_flash_mcp7x},
+	{0x10de, 0x03e2, NT, "NVIDIA", "MCP61",		enable_flash_mcp7x},
+	{0x10de, 0x03e3, NT, "NVIDIA", "MCP61",		enable_flash_mcp7x},
+	{0x10de, 0x0440, NT, "NVIDIA", "MCP65",		enable_flash_mcp7x},
+	{0x10de, 0x0441, NT, "NVIDIA", "MCP65",		enable_flash_mcp7x},
+	{0x10de, 0x0442, NT, "NVIDIA", "MCP65",		enable_flash_mcp7x},
+	{0x10de, 0x0443, NT, "NVIDIA", "MCP65",		enable_flash_mcp7x},
+	{0x10de, 0x0548, OK, "NVIDIA", "MCP67",		enable_flash_mcp67},
+	{0x10de, 0x075c, NT, "NVIDIA", "MCP78S",	enable_flash_mcp7x},
+	{0x10de, 0x075d, NT, "NVIDIA", "MCP78S",	enable_flash_mcp7x},
+	{0x10de, 0x07d7, NT, "NVIDIA", "MCP73",		enable_flash_mcp7x},
+	{0x10de, 0x0aac, NT, "NVIDIA", "MCP79",		enable_flash_mcp7x},
+	{0x10de, 0x0aad, NT, "NVIDIA", "MCP79",		enable_flash_mcp7x},
+	{0x10de, 0x0aae, NT, "NVIDIA", "MCP79",		enable_flash_mcp7x},
+	{0x10de, 0x0aaf, NT, "NVIDIA", "MCP79",		enable_flash_mcp7x},
 	{0x1039, 0x0496, NT, "SiS", "85C496+497",	enable_flash_sis85c496},
 	{0x1039, 0x0406, NT, "SiS", "501/5101/5501",	enable_flash_sis501},
 	{0x1039, 0x5511, NT, "SiS", "5511",		enable_flash_sis5511},