Fix VIA VX*** support

Helge Wagner's patch that added VIA VX900 chipset support made me look
closer at the datasheets which led to some concise documentation about
newer VIA chipsets: http://flashrom.org/VIA

Based on that this patch adds full support for VX800/VX820, VX855/VX875
and VX900, including SPI and LPC. VT8237S was not changed (SPI support
only) because there is no public datasheet and it is not clear how to
distinguish between LPC and SPI strapping and investigations in (NDAed)
documents have not brought up anything conclusively.

enable_flash_vt823x could probably be enhanced too due to various
ignored LPC options of the chipset.

Corresponding to flashrom svn r1578.

Signed-off-by: Helge Wagner <Helge.Wagner@ge.com>
Signed-off-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
Tested-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Acked-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
diff --git a/chipset_enable.c b/chipset_enable.c
index 936d7b8..39e59dd 100644
--- a/chipset_enable.c
+++ b/chipset_enable.c
@@ -6,6 +6,7 @@
  * Copyright (C) 2006 Uwe Hermann <uwe@hermann-uwe.de>
  * Copyright (C) 2007,2008,2009 Carl-Daniel Hailfinger
  * Copyright (C) 2009 Kontron Modular Computers GmbH
+ * Copyright (C) 2011, 2012 Stefan Tauner
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -508,12 +509,6 @@
 	return ret;
 }
 
-static int enable_flash_vt8237s_spi(struct pci_dev *dev, const char *name)
-{
-	/* Do we really need no write enable? */
-	return via_init_spi(dev);
-}
-
 static int enable_flash_ich_dc_spi(struct pci_dev *dev, const char *name,
 				   enum ich_chipset ich_generation)
 {
@@ -681,7 +676,7 @@
 		return -1;
 	}
 
-	if (dev->device_id == 0x3227) { /* VT8237R */
+	if (dev->device_id == 0x3227) { /* VT8237/VT8237R */
 		/* All memory cycles, not just ROM ones, go to LPC. */
 		val = pci_read_byte(dev, 0x59);
 		val &= ~0x80;
@@ -691,6 +686,69 @@
 	return 0;
 }
 
+static int enable_flash_vt_vx(struct pci_dev *dev, const char *name)
+{
+	struct pci_dev *south_north = pci_dev_find(0x1106, 0xa353);
+	if (south_north == NULL) {
+		msg_perr("Could not find South-North Module Interface Control device!\n");
+		return ERROR_FATAL;
+	}
+
+	msg_pdbg("Strapped to ");
+	if ((pci_read_byte(south_north, 0x56) & 0x01) == 0) {
+		msg_pdbg("LPC.\n");
+		return enable_flash_vt823x(dev, name);
+	}
+	msg_pdbg("SPI.\n");
+
+	uint32_t mmio_base;
+	void *mmio_base_physmapped;
+	uint32_t spi_cntl;
+	#define SPI_CNTL_LEN 0x08
+	uint32_t spi0_mm_base = 0;
+	switch(dev->device_id) {
+		case 0x8353: /* VX800/VX820 */
+			spi0_mm_base = pci_read_long(dev, 0xbc) << 8;
+			break;
+		case 0x8409: /* VX855/VX875 */
+		case 0x8410: /* VX900 */
+			mmio_base = pci_read_long(dev, 0xbc) << 8;
+			mmio_base_physmapped = physmap("VIA VX MMIO register", mmio_base, SPI_CNTL_LEN);
+			if (mmio_base_physmapped == ERROR_PTR) {
+				physunmap(mmio_base_physmapped, SPI_CNTL_LEN);
+				return ERROR_FATAL;
+			}
+
+			/* Offset 0 - Bit 0 holds SPI Bus0 Enable Bit. */
+			spi_cntl = mmio_readl(mmio_base_physmapped) + 0x00;
+			if ((spi_cntl & 0x01) == 0) {
+				msg_pdbg ("SPI Bus0 disabled!\n");
+				physunmap(mmio_base_physmapped, SPI_CNTL_LEN);
+				return ERROR_FATAL;
+			}
+			/* Offset 1-3 has  SPI Bus Memory Map Base Address: */
+			spi0_mm_base = spi_cntl & 0xFFFFFF00;
+
+			/* Offset 4 - Bit 0 holds SPI Bus1 Enable Bit. */
+			spi_cntl = mmio_readl(mmio_base_physmapped) + 0x04;
+			if ((spi_cntl & 0x01) == 1)
+				msg_pdbg2("SPI Bus1 is enabled too.\n");
+
+			physunmap(mmio_base_physmapped, SPI_CNTL_LEN);
+			break;
+		default:
+			msg_perr("%s: Unsupported chipset %x:%x!\n", __func__, dev->vendor_id, dev->device_id);
+			return ERROR_FATAL;
+	}
+
+	return via_init_spi(dev, spi0_mm_base);
+}
+
+static int enable_flash_vt8237s_spi(struct pci_dev *dev, const char *name)
+{
+	return via_init_spi(dev, pci_read_long(dev, 0xbc) << 8);
+}
+
 static int enable_flash_cs5530(struct pci_dev *dev, const char *name)
 {
 	uint8_t reg8;
@@ -1266,13 +1324,14 @@
 	{0x1106, 0x3074, OK, "VIA", "VT8233",		enable_flash_vt823x},
 	{0x1106, 0x3147, OK, "VIA", "VT8233A",		enable_flash_vt823x},
 	{0x1106, 0x3177, OK, "VIA", "VT8235",		enable_flash_vt823x},
-	{0x1106, 0x3227, OK, "VIA", "VT8237",		enable_flash_vt823x},
+	{0x1106, 0x3227, OK, "VIA", "VT8237(R)",	enable_flash_vt823x},
 	{0x1106, 0x3337, OK, "VIA", "VT8237A",		enable_flash_vt823x},
 	{0x1106, 0x3372, OK, "VIA", "VT8237S",		enable_flash_vt8237s_spi},
 	{0x1106, 0x8231, NT, "VIA", "VT8231",		enable_flash_vt823x},
 	{0x1106, 0x8324, OK, "VIA", "CX700",		enable_flash_vt823x},
-	{0x1106, 0x8353, OK, "VIA", "VX800/VX820",	enable_flash_vt8237s_spi},
-	{0x1106, 0x8409, OK, "VIA", "VX855/VX875",	enable_flash_vt823x},
+	{0x1106, 0x8353, NT, "VIA", "VX800/VX820",	enable_flash_vt_vx},
+	{0x1106, 0x8409, NT, "VIA", "VX855/VX875",	enable_flash_vt_vx},
+	{0x1106, 0x8410, NT, "VIA", "VX900",		enable_flash_vt_vx},
 	{0x1166, 0x0200, OK, "Broadcom", "OSB4",	enable_flash_osb4},
 	{0x1166, 0x0205, OK, "Broadcom", "HT-1000",	enable_flash_ht1000},
 	{0x17f3, 0x6030, OK, "RDC", "R8610/R3210",	enable_flash_rdc_r8610},