MX31: Add NAND SPL for i.MX31.

This patch adds the NAND SPL framework needed to boot i.MX31 boards
from NAND.

It has been tested on a i.MX31 PDK board with large page NAND. Small
page NANDs should work as well, but this has not been tested.

Note: The i.MX31 NFC uses a non-standard layout for large page NANDs,
whether this is compatible with a particular setup depends on how
the NAND device is programmed by the flash programmer (e.g. JTAG
debugger).

The patch is based on the work by Maxim Artamonov.

Signed-off-by: Maxim Artamonov <scn1874@yandex.ru>
Signed-off-by: Magnus Lilja <lilja.magnus@gmail.com>

1 files changed, 259 insertions, 0 deletions

diff --git a/nand_spl/nand_boot_fsl_nfc.c b/nand_spl/nand_boot_fsl_nfc.c
new file mode 100644
index 0000000..a9df2a8
--- /dev/null
+++ b/nand_spl/nand_boot_fsl_nfc.c
@@ -0,0 +1,259 @@
+/*
+ * (C) Copyright 2009
+ * Magnus Lilja <lilja.magnus@gmail.com>
+ *
+ * (C) Copyright 2008
+ * Maxim Artamonov, <scn1874 at yandex.ru>
+ *
+ * (C) Copyright 2006-2008
+ * Stefan Roese, DENX Software Engineering, sr at 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>
+#include <asm-arm/arch/mx31-regs.h>
+#include <asm/io.h>
+#include <fsl_nfc.h>
+
+static struct fsl_nfc_regs *nfc;
+
+static void nfc_wait_ready(void)
+{
+	uint32_t tmp;
+
+	while (!(readw(&nfc->nand_flash_config2) & NFC_INT))
+		;
+
+	/* Reset interrupt flag */
+	tmp = readw(&nfc->nand_flash_config2);
+	tmp &= ~NFC_INT;
+	writew(tmp, &nfc->nand_flash_config2);
+}
+
+static void nfc_nand_init(void)
+{
+	/* unlocking RAM Buff */
+	writew(0x2, &nfc->configuration);
+
+	/* hardware ECC checking and correct */
+	writew(NFC_ECC_EN, &nfc->nand_flash_config1);
+}
+
+static void nfc_nand_command(unsigned short command)
+{
+	writew(command, &nfc->flash_cmd);
+	writew(NFC_CMD, &nfc->nand_flash_config2);
+	nfc_wait_ready();
+}
+
+static void nfc_nand_page_address(unsigned int page_address)
+{
+	unsigned int page_count;
+
+	writew(0x00, &nfc->flash_cmd);
+	writew(NFC_ADDR, &nfc->nand_flash_config2);
+	nfc_wait_ready();
+
+	/* code only for 2kb flash */
+	if (CONFIG_SYS_NAND_PAGE_SIZE == 0x800) {
+		writew(0x00, &nfc->flash_add);
+		writew(NFC_ADDR, &nfc->nand_flash_config2);
+		nfc_wait_ready();
+	}
+
+	page_count = CONFIG_SYS_NAND_SIZE / CONFIG_SYS_NAND_PAGE_SIZE;
+
+	if (page_address <= page_count) {
+		page_count--; /* transform 0x01000000 to 0x00ffffff */
+		do {
+			writew(page_address & 0xff, &nfc->flash_add);
+			writew(NFC_ADDR, &nfc->nand_flash_config2);
+			nfc_wait_ready();
+			page_address = page_address >> 8;
+			page_count = page_count >> 8;
+		} while (page_count);
+	}
+}
+
+static void nfc_nand_data_output(void)
+{
+	int i;
+
+	/*
+	 * The NAND controller requires four output commands for
+	 * large page devices.
+	 */
+	for (i = 0; i < (CONFIG_SYS_NAND_PAGE_SIZE / 512); i++) {
+		writew(NFC_ECC_EN, &nfc->nand_flash_config1);
+		writew(i, &nfc->buffer_address); /* read in i:th buffer */
+		writew(NFC_OUTPUT, &nfc->nand_flash_config2);
+		nfc_wait_ready();
+	}
+}
+
+static int nfc_nand_check_ecc(void)
+{
+	return readw(&nfc->ecc_status_result);
+}
+
+static int nfc_read_page(unsigned int page_address, unsigned char *buf)
+{
+	int i;
+	u32 *src;
+	u32 *dst;
+
+	writew(0, &nfc->buffer_address); /* read in first 0 buffer */
+	nfc_nand_command(NAND_CMD_READ0);
+	nfc_nand_page_address(page_address);
+
+	if (CONFIG_SYS_NAND_PAGE_SIZE == 0x800)
+		nfc_nand_command(NAND_CMD_READSTART);
+
+	nfc_nand_data_output(); /* fill the main buffer 0 */
+
+	if (nfc_nand_check_ecc())
+		return -1;
+
+	src = &nfc->main_area0[0];
+	dst = (u32 *)buf;
+
+	/* main copy loop from NAND-buffer to SDRAM memory */
+	for (i = 0; i < (CONFIG_SYS_NAND_PAGE_SIZE / 4); i++) {
+		writel(readl(src), dst);
+		src++;
+		dst++;
+	}
+
+	return 0;
+}
+
+static int is_badblock(int pagenumber)
+{
+	int page = pagenumber;
+	u32 badblock;
+	u32 *src;
+
+	/* Check the first two pages for bad block markers */
+	for (page = pagenumber; page < pagenumber + 2; page++) {
+		writew(0, &nfc->buffer_address); /* read in first 0 buffer */
+		nfc_nand_command(NAND_CMD_READ0);
+		nfc_nand_page_address(page);
+
+		if (CONFIG_SYS_NAND_PAGE_SIZE == 0x800)
+			nfc_nand_command(NAND_CMD_READSTART);
+
+		nfc_nand_data_output(); /* fill the main buffer 0 */
+
+		src = &nfc->spare_area0[0];
+
+		/*
+		 * IMPORTANT NOTE: The nand flash controller uses a non-
+		 * standard layout for large page devices. This can
+		 * affect the position of the bad block marker.
+		 */
+		/* Get the bad block marker */
+		badblock = readl(&src[CONFIG_SYS_NAND_BAD_BLOCK_POS / 4]);
+		badblock >>= 8 * (CONFIG_SYS_NAND_BAD_BLOCK_POS % 4);
+		badblock &= 0xff;
+
+		/* bad block marker verify */
+		if (badblock != 0xff)
+			return 1; /* potential bad block */
+	}
+
+	return 0;
+}
+
+static int nand_load(unsigned int from, unsigned int size, unsigned char *buf)
+{
+	int i;
+	unsigned int page;
+	unsigned int maxpages = CONFIG_SYS_NAND_SIZE /
+				CONFIG_SYS_NAND_PAGE_SIZE;
+
+	nfc = (void *)NFC_BASE_ADDR;
+
+	nfc_nand_init();
+
+	/* Convert to page number */
+	page = from / CONFIG_SYS_NAND_PAGE_SIZE;
+	i = 0;
+
+	while (i < (size / CONFIG_SYS_NAND_PAGE_SIZE)) {
+		if (nfc_read_page(page, buf) < 0)
+			return -1;
+
+		page++;
+		i++;
+		buf = buf + CONFIG_SYS_NAND_PAGE_SIZE;
+
+		/*
+		 * Check if we have crossed a block boundary, and if so
+		 * check for bad block.
+		 */
+		if (!(page % CONFIG_SYS_NAND_PAGE_COUNT)) {
+			/*
+			 * Yes, new block. See if this block is good. If not,
+			 * loop until we find i good block.
+			 */
+			while (is_badblock(page)) {
+				page = page + CONFIG_SYS_NAND_PAGE_COUNT;
+				/* Check i we've reached the end of flash. */
+				if (page >= maxpages)
+					return -1;
+			}
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * The main entry for NAND booting. It's necessary that SDRAM is already
+ * configured and available since this code loads the main U-Boot image
+ * from NAND into SDRAM and starts it from there.
+ */
+void nand_boot(void)
+{
+	__attribute__((noreturn)) void (*uboot)(void);
+
+	nfc = (void *)NFC_BASE_ADDR;
+
+	/*
+	 * CONFIG_SYS_NAND_U_BOOT_OFFS and CONFIG_SYS_NAND_U_BOOT_SIZE must
+	 * be aligned to full pages
+	 */
+	if (!nand_load(CONFIG_SYS_NAND_U_BOOT_OFFS, CONFIG_SYS_NAND_U_BOOT_SIZE,
+		       (uchar *)CONFIG_SYS_NAND_U_BOOT_DST)) {
+		/* Copy from NAND successful, start U-boot */
+		uboot = (void *)CONFIG_SYS_NAND_U_BOOT_START;
+		uboot();
+	} else {
+		/* Unrecoverable error when copying from NAND */
+		hang();
+	}
+}
+
+/*
+ * Called in case of an exception.
+ */
+void hang(void)
+{
+	/* Loop forever */
+	while (1) ;
+}