Add PIXIS FPGA support for MPC8641HPCN board.

Move the 8641HPCN's PIXIS code to the new directory
board/freescale/common/ as it will be shared by
future boards not in the same processor family.

Write a "pixis_reset" command that utilizes the FPGA
reset sequencer to support alternate soft-reset options
such as using the "alternate" flash bank, enabling
the watch dog, or choosing different CPU frequencies.

Add documentation for the pixis_reset to README.mpc8641hpcn.

Signed-off-by: Haiying Wang <haiying.wang@freescale.com>
Signed-off-by: Jon Loeliger <jdl@freescale.com>
diff --git a/board/freescale/common/pixis.h b/board/freescale/common/pixis.h
new file mode 100644
index 0000000..ff62a62
--- /dev/null
+++ b/board/freescale/common/pixis.h
@@ -0,0 +1,31 @@
+/*
+ * Copyright 2006 Freescale Semiconductor
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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 the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+extern void pixis_reset(void);
+extern int set_px_sysclk(ulong sysclk);
+extern int set_px_mpxpll(ulong mpxpll);
+extern int set_px_corepll(ulong corepll);
+extern void read_from_px_regs(int set);
+extern void read_from_px_regs_altbank(int set);
+extern void set_altbank(void);
+extern void set_px_go(void);
+extern void set_px_go_with_watchdog(void);