Add support for AMCC Sequoia PPC440EPx eval board
- Add support for PPC440EPx & PPC440GRx
- Add support for PPC440EP(x)/GR(x) NAND controller
  in cpu/ppc4xx directory
- Add NAND boot functionality for Sequoia board,
  please see doc/README.nand-boot-ppc440 for details
- This Sequoia NAND image doesn't support environment
  in NAND for now. This will be added in a short while.
Patch by Stefan Roese, 07 Sep 2006
diff --git a/nand_spl/nand_boot.c b/nand_spl/nand_boot.c
new file mode 100644
index 0000000..6e3af13
--- /dev/null
+++ b/nand_spl/nand_boot.c
@@ -0,0 +1,178 @@
+/*
+ * (C) Copyright 2006
+ * Stefan Roese, DENX Software Engineering, sr@denx.de.
+ *
+ * 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
+ */
+
+#include <common.h>
+#include <nand.h>
+
+#define CFG_NAND_READ_DELAY \
+	{ volatile int dummy; int i; for (i=0; i<10000; i++) dummy = i; }
+
+extern void board_nand_init(struct nand_chip *nand);
+extern void ndfc_hwcontrol(struct mtd_info *mtdinfo, int cmd);
+extern void ndfc_write_byte(struct mtd_info *mtdinfo, u_char byte);
+extern u_char ndfc_read_byte(struct mtd_info *mtdinfo);
+extern int ndfc_dev_ready(struct mtd_info *mtdinfo);
+extern int jump_to_ram(ulong delta);
+extern int jump_to_uboot(ulong addr);
+
+static int nand_is_bad_block(struct mtd_info *mtd, int block)
+{
+        struct nand_chip *this = mtd->priv;
+	int page_addr = block * CFG_NAND_PAGE_COUNT;
+
+	/* Begin command latch cycle */
+	this->hwcontrol(mtd, NAND_CTL_SETCLE);
+	this->write_byte(mtd, NAND_CMD_READOOB);
+	/* Set ALE and clear CLE to start address cycle */
+	this->hwcontrol(mtd, NAND_CTL_CLRCLE);
+	this->hwcontrol(mtd, NAND_CTL_SETALE);
+	/* Column address */
+	this->write_byte(mtd, CFG_NAND_BAD_BLOCK_POS);			/* A[7:0] */
+	this->write_byte(mtd, (uchar)(page_addr & 0xff));		/* A[16:9] */
+	this->write_byte(mtd, (uchar)((page_addr >> 8) & 0xff));	/* A[24:17] */
+#ifdef CFG_NAND_4_ADDR_CYCLE
+	/* One more address cycle for devices > 32MiB */
+	this->write_byte(mtd, (uchar)((page_addr >> 16) & 0x0f));	/* A[xx:25] */
+#endif
+	/* Latch in address */
+	this->hwcontrol(mtd, NAND_CTL_CLRALE);
+
+	/*
+	 * Wait a while for the data to be ready
+	 */
+	if (this->dev_ready)
+		this->dev_ready(mtd);
+	else
+		CFG_NAND_READ_DELAY;
+
+	/*
+	 * Read on byte
+	 */
+	if (this->read_byte(mtd) != 0xff)
+		return 1;
+
+	return 0;
+}
+
+static int nand_read_page(struct mtd_info *mtd, int block, int page, uchar *dst)
+{
+        struct nand_chip *this = mtd->priv;
+	int page_addr = page + block * CFG_NAND_PAGE_COUNT;
+	int i;
+
+	/* Begin command latch cycle */
+	this->hwcontrol(mtd, NAND_CTL_SETCLE);
+	this->write_byte(mtd, NAND_CMD_READ0);
+	/* Set ALE and clear CLE to start address cycle */
+	this->hwcontrol(mtd, NAND_CTL_CLRCLE);
+	this->hwcontrol(mtd, NAND_CTL_SETALE);
+	/* Column address */
+	this->write_byte(mtd, 0);					/* A[7:0] */
+	this->write_byte(mtd, (uchar)(page_addr & 0xff));		/* A[16:9] */
+	this->write_byte(mtd, (uchar)((page_addr >> 8) & 0xff));	/* A[24:17] */
+#ifdef CFG_NAND_4_ADDR_CYCLE
+	/* One more address cycle for devices > 32MiB */
+	this->write_byte(mtd, (uchar)((page_addr >> 16) & 0x0f));	/* A[xx:25] */
+#endif
+	/* Latch in address */
+	this->hwcontrol(mtd, NAND_CTL_CLRALE);
+
+	/*
+	 * Wait a while for the data to be ready
+	 */
+	if (this->dev_ready)
+		this->dev_ready(mtd);
+	else
+		CFG_NAND_READ_DELAY;
+
+	/*
+	 * Read page into buffer
+	 */
+	for (i=0; i<CFG_NAND_PAGE_SIZE; i++)
+		*dst++ = this->read_byte(mtd);
+
+	return 0;
+}
+
+static int nand_load(struct mtd_info *mtd, int offs, int uboot_size, uchar *dst)
+{
+	int block;
+	int blockcopy_count;
+	int page;
+
+	/*
+	 * offs has to be aligned to a block address!
+	 */
+	block = offs / CFG_NAND_BLOCK_SIZE;
+	blockcopy_count = 0;
+
+	while (blockcopy_count < (uboot_size / CFG_NAND_BLOCK_SIZE)) {
+		if (!nand_is_bad_block(mtd, block)) {
+			/*
+			 * Skip bad blocks
+			 */
+			for (page = 0; page < CFG_NAND_PAGE_COUNT; page++) {
+				nand_read_page(mtd, block, page, dst);
+				dst += CFG_NAND_PAGE_SIZE;
+			}
+
+			blockcopy_count++;
+		}
+
+		block++;
+	}
+
+	return 0;
+}
+
+void nand_boot(void)
+{
+	ulong mem_size;
+	struct nand_chip nand_chip;
+	nand_info_t nand_info;
+	int ret;
+	void (*uboot)(void);
+
+	/*
+	 * Init sdram, so we have access to memory
+	 */
+	mem_size = initdram(0);
+
+	/*
+	 * Init board specific nand support
+	 */
+	nand_info.priv = &nand_chip;
+	nand_chip.IO_ADDR_R = nand_chip.IO_ADDR_W = (void  __iomem *)CFG_NAND_BASE;
+	nand_chip.dev_ready = NULL;	/* preset to NULL */
+	board_nand_init(&nand_chip);
+
+	/*
+	 * Load U-Boot image from NAND into RAM
+	 */
+	ret = nand_load(&nand_info, CFG_NAND_U_BOOT_OFFS,
+			CFG_NAND_U_BOOT_SIZE,
+			(uchar *)CFG_NAND_U_BOOT_DST);
+
+	/*
+	 * Jump to U-Boot image
+	 */
+	uboot = (void (*)(void))CFG_NAND_U_BOOT_START;
+	(*uboot)();
+}