[PATCH] matroxfb: read MGA PInS data on PowerPC

This updates the matroxfb code so that it can find the PInS data embedded
in the BIOS on PowerPC cards.  The process for finding the data is
different on OpenFirmware cards than on x86 cards, and the code for doing
so was missing.

After patching, building, installing, and booting a kernel, you should grep
for "PInS" in /var/log/messages.  You should see two messages in the log:

PInS data found at offset XXXXX
PInS memtype = X

On the GXT135p card I get "31168" and "5".  The first value is irrelevant,
but it's presence lets me know that the PInS data was actually found.  On a
GXT130p, the second value should be 3.  Since I don't have access to that
hardware, if someone can verify that, I will submit a follow-on patch that
rips out all the memtype parameter stuff.
Signed-off-by: Ian Romanick <idr@us.ibm.com>
Signed-off-by: Petr Vandrovec <vandrove@vc.cvut.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/video/matrox/matroxfb_misc.c

@@ -68,6 +68,9 @@
  *               "David C. Hansen" <haveblue@us.ibm.com>
  *                     Fixes
  *
+ *               "Ian Romanick" <idr@us.ibm.com>
+ *                     Find PInS data in BIOS on PowerPC systems.
+ *
  * (following author is not in any relation with this code, but his code
  *  is included in this driver)
  *
@@ -496,10 +499,35 @@ static void parse_bios(unsigned char __iomem* vbios, struct matrox_bios* bd) {
 	get_bios_version(vbios, bd);
 	get_bios_output(vbios, bd);
 	get_bios_tvout(vbios, bd);
+#if defined(__powerpc__)
+	/* On PowerPC cards, the PInS offset isn't stored at the end of the
+	 * BIOS image.  Instead, you must search the entire BIOS image for
+	 * the magic PInS signature.
+	 *
+	 * This actually applies to all OpenFirmware base cards.  Since these
+	 * cards could be put in a MIPS or SPARC system, should the condition
+	 * be something different?
+	 */
+	for ( pins_offset = 0 ; pins_offset <= 0xFF80 ; pins_offset++ ) {
+		unsigned char header[3];
+
+		header[0] = readb(vbios + pins_offset);
+		header[1] = readb(vbios + pins_offset + 1);
+		header[2] = readb(vbios + pins_offset + 2);
+		if ( (header[0] == 0x2E) && (header[1] == 0x41)
+		     && ((header[2] == 0x40) || (header[2] == 0x80)) ) {
+			printk(KERN_INFO "PInS data found at offset %u\n",
+			       pins_offset);
+			get_pins(vbios + pins_offset, bd);
+			break;
+		}
+	}
+#else
 	pins_offset = readb(vbios + 0x7FFC) | (readb(vbios + 0x7FFD) << 8);
 	if (pins_offset <= 0xFF80) {
 		get_pins(vbios + pins_offset, bd);
 	}
+#endif
 }
 
 #define get_u16(x) (le16_to_cpu(get_unaligned((__u16*)(x))))
@@ -755,6 +783,8 @@ void matroxfb_read_pins(WPMINFO2) {
 	}
 #endif
 	matroxfb_set_limits(PMINFO &ACCESS_FBINFO(bios));
+	printk(KERN_INFO "PInS memtype = %u\n",
+	       (ACCESS_FBINFO(values).reg.opt & 0x1C00) >> 10);
 }
 
 EXPORT_SYMBOL(matroxfb_DAC_in);