ichspi: try harder to conform to address restrictions

ICH SPI can enforce address restrictions for all accesses which take an
address (well, it could if the chipset implementation was not broken).
Since exploiting the broken implementation is harder than conforming
to the address restrictions wherever possible, conform to the address
restrictions instead. This patch eliminates a lot of transaction errors
people were seeing on chip probe.

Corresponding to flashrom svn r1016.
Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
Acked-by: Stefan Reinauer <stepan@coresystems.de>

chipset_enable.c

@@ -36,8 +36,6 @@
 
 #if defined(__i386__) || defined(__x86_64__)
 
-extern int ichspi_lock;
-
 static int enable_flash_ali_m1533(struct pci_dev *dev, const char *name)
 {
 	uint8_t tmp;
@@ -515,8 +513,9 @@ static int enable_flash_ich_dc_spi(struct pci_dev *dev, const char *name,
 			msg_pdbg("0x%02x: 0x%08x (SPID%d+4)\n", offs + 4,
 				     mmio_readl(spibar + offs + 4), i);
 		}
+		ichspi_bbar = mmio_readl(spibar + 0x50);
 		msg_pdbg("0x50: 0x%08x (BBAR)\n",
-			     mmio_readl(spibar + 0x50));
+			     ichspi_bbar);
 		msg_pdbg("0x54: 0x%04x     (PREOP)\n",
 			     mmio_readw(spibar + 0x54));
 		msg_pdbg("0x56: 0x%04x     (OPTYPE)\n",
@@ -587,8 +586,9 @@ static int enable_flash_ich_dc_spi(struct pci_dev *dev, const char *name,
 			     mmio_readl(spibar + 0x98));
 		msg_pdbg("0x9C: 0x%08x (OPMENU+4)\n",
 			     mmio_readl(spibar + 0x9C));
+		ichspi_bbar = mmio_readl(spibar + 0xA0);
 		msg_pdbg("0xA0: 0x%08x (BBAR)\n",
-			     mmio_readl(spibar + 0xA0));
+			     ichspi_bbar);
 		msg_pdbg("0xB0: 0x%08x (FDOC)\n",
 			     mmio_readl(spibar + 0xB0));
 		if (tmp2 & (1 << 15)) {

flash.h

@@ -663,6 +663,8 @@ int default_spi_send_multicommand(struct spi_command *cmds);
 uint32_t spi_get_valid_read_addr(void);
 
 /* ichspi.c */
+extern int ichspi_lock;
+extern uint32_t ichspi_bbar;
 int ich_init_opcodes(void);
 int ich_spi_send_command(unsigned int writecnt, unsigned int readcnt,
 		    const unsigned char *writearr, unsigned char *readarr);

ichspi.c

@@ -103,6 +103,8 @@
 /* ICH SPI configuration lock-down. May be set during chipset enabling. */
 int ichspi_lock = 0;
 
+uint32_t ichspi_bbar = 0;
+
 typedef struct _OPCODE {
 	uint8_t opcode;		//This commands spi opcode
 	uint8_t spi_type;	//This commands spi type
@@ -327,6 +329,34 @@ int program_opcodes(OPCODES * op)
 	return 0;
 }
 
+/*
+ * Try to set BBAR (BIOS Base Address Register), but read back the value in case
+ * it didn't stick.
+ */
+void ich_set_bbar(uint32_t minaddr)
+{
+	switch (spi_controller) {
+	case SPI_CONTROLLER_ICH7:
+		mmio_writel(minaddr, spibar + 0x50);
+		ichspi_bbar = mmio_readl(spibar + 0x50);
+		/* We don't have any option except complaining. */
+		if (ichspi_bbar != minaddr)
+			msg_perr("Setting BBAR failed!\n");
+		break;
+	case SPI_CONTROLLER_ICH9:
+		mmio_writel(minaddr, spibar + 0xA0);
+		ichspi_bbar = mmio_readl(spibar + 0xA0);
+		/* We don't have any option except complaining. */
+		if (ichspi_bbar != minaddr)
+			msg_perr("Setting BBAR failed!\n");
+		break;
+	default:
+		/* Not sure if BBAR actually exists on VIA. */
+		msg_pdbg("Setting BBAR is not implemented for VIA yet.\n");
+		break;
+	}
+}
+
 /* This function generates OPCODES from or programs OPCODES to ICH according to
  * the chipset's SPI configuration lock.
  *
@@ -341,13 +371,18 @@ int ich_init_opcodes(void)
 		return 0;
 
 	if (ichspi_lock) {
-		msg_pdbg("Generating OPCODES... ");
+		msg_pdbg("Reading OPCODES... ");
 		curopcodes_done = &O_EXISTING;
 		rc = generate_opcodes(curopcodes_done);
 	} else {
 		msg_pdbg("Programming OPCODES... ");
 		curopcodes_done = &O_ST_M25P;
 		rc = program_opcodes(curopcodes_done);
+		/* Technically not part of opcode init, but it allows opcodes
+		 * to run without transaction errors by setting the lowest
+		 * allowed address to zero.
+		 */
+		ich_set_bbar(0);
 	}
 
 	if (rc) {
@@ -743,6 +778,19 @@ int ich_spi_send_command(unsigned int writecnt, unsigned int readcnt,
 	    opcode->spi_type == SPI_OPCODE_TYPE_WRITE_WITH_ADDRESS) {
 		addr = (writearr[1] << 16) |
 		    (writearr[2] << 8) | (writearr[3] << 0);
+		switch (spi_controller) {
+		case SPI_CONTROLLER_ICH7:
+		case SPI_CONTROLLER_ICH9:
+			if (addr < ichspi_bbar) {
+				msg_perr("%s: Address 0x%06x below allowed "
+					 "range 0x%06x-0xffffff\n", __func__,
+					 addr, ichspi_bbar);
+				return SPI_INVALID_ADDRESS;
+			}
+			break;
+		default:
+			break;
+		}
 	}
 
 	/* translate read/write array/count */

spi.c

@@ -207,8 +207,22 @@ int spi_chip_write_256(struct flashchip *flash, uint8_t *buf)
 	return spi_programmer[spi_controller].write_256(flash, buf);
 }
 
+/*
+ * Get the lowest allowed address for read accesses. This often happens to
+ * be the lowest allowed address for all commands which take an address.
+ * This is a programmer limitation.
+ */
 uint32_t spi_get_valid_read_addr(void)
 {
-	/* Need to return BBAR for ICH chipsets. */
-	return 0;
+	switch (spi_controller) {
+#if INTERNAL_SUPPORT == 1
+#if defined(__i386__) || defined(__x86_64__)
+	case SPI_CONTROLLER_ICH7:
+		/* Return BBAR for ICH chipsets. */
+		return ichspi_bbar;
+#endif
+#endif
+	default:
+		return 0;
+	}
 }