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>

4 files changed, 380 insertions, 2 deletions

diff --git a/cpu/arm1136/start.S b/cpu/arm1136/start.S
index 28cb5fd..957f438 100644
--- a/cpu/arm1136/start.S
+++ b/cpu/arm1136/start.S
@@ -200,12 +200,15 @@ clbss_l:str	r2, [r0]		/* clear loop...		    */
 
 	ldr	pc, _start_armboot
 
+#ifdef CONFIG_NAND_SPL
+_start_armboot: .word nand_boot
+#else
 #ifdef CONFIG_ONENAND_IPL
 _start_armboot: .word start_oneboot
 #else
 _start_armboot: .word start_armboot
-#endif
-
+#endif /* CONFIG_ONENAND_IPL */
+#endif /* CONFIG_NAND_SPL */
 
 /*
  *************************************************************************
@@ -217,6 +220,7 @@ _start_armboot: .word start_armboot
  *
  *************************************************************************
  */
+#ifndef CONFIG_SKIP_LOWLEVEL_INIT
 cpu_init_crit:
 	/*
 	 * flush v4 I/D caches
@@ -243,6 +247,7 @@ cpu_init_crit:
 	bl	lowlevel_init	/* go setup pll,mux,memory */
 	mov	lr, ip		/* restore link */
 	mov	pc, lr		/* back to my caller */
+#endif /* CONFIG_SKIP_LOWLEVEL_INIT */
 
 #ifndef CONFIG_PRELOADER
 /*
diff --git a/include/asm-arm/arch-mx31/mx31-regs.h b/include/asm-arm/arch-mx31/mx31-regs.h
index a8a05c8..c2e7dcf 100644
--- a/include/asm-arm/arch-mx31/mx31-regs.h
+++ b/include/asm-arm/arch-mx31/mx31-regs.h
@@ -194,4 +194,9 @@
 #define CS5_BASE	0xB6000000
 #define PCMCIA_MEM_BASE	0xC0000000
 
+/*
+ * NAND controller
+ */
+#define NFC_BASE_ADDR	0xB8000000
+
 #endif /* __ASM_ARCH_MX31_REGS_H */
diff --git a/include/fsl_nfc.h b/include/fsl_nfc.h
new file mode 100644
index 0000000..da5be37
--- /dev/null
+++ b/include/fsl_nfc.h
@@ -0,0 +1,109 @@
+/*
+ *
+ * (c) 2009 Magnus Lilja <lilja.magnus@gmail.com>
+ *
+ * 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
+ */
+
+#ifndef __FSL_NFC_H
+#define __FSL_NFC_H
+
+/*
+ * Register map and bit definitions for the Freescale NAND Flash
+ * Controller present in i.MX31 and other devices.
+ */
+
+struct fsl_nfc_regs {
+	u32 main_area0[128]; /* @0x000 */
+	u32 main_area1[128];
+	u32 main_area2[128];
+	u32 main_area3[128];
+	u32 spare_area0[4];
+	u32 spare_area1[4];
+	u32 spare_area2[4];
+	u32 spare_area3[4];
+	u32 reserved1[64 - 16 + 64 * 5];
+	u16 bufsiz; /* @ 0xe00 */
+	u16 reserved2;
+	u16 buffer_address;
+	u16 flash_add;
+	u16 flash_cmd;
+	u16 configuration;
+	u16 ecc_status_result;
+	u16 ecc_rslt_main_area;
+	u16 ecc_rslt_spare_area;
+	u16 nf_wr_prot;
+	u16 unlock_start_blk_add;
+	u16 unlock_end_blk_add;
+	u16 nand_flash_wr_pr_st;
+	u16 nand_flash_config1;
+	u16 nand_flash_config2;
+};
+
+/*
+ * Set INT to 0, FCMD to 1, rest to 0 in NFC_CONFIG2 Register for Command
+ * operation
+ */
+#define NFC_CMD		0x1
+
+/*
+ * Set INT to 0, FADD to 1, rest to 0 in NFC_CONFIG2 Register for Address
+ * operation
+ */
+#define NFC_ADDR	0x2
+
+/*
+ * Set INT to 0, FDI to 1, rest to 0 in NFC_CONFIG2 Register for Input
+ * operation
+ */
+#define NFC_INPUT	0x4
+
+/*
+ * Set INT to 0, FDO to 001, rest to 0 in NFC_CONFIG2 Register for Data
+ * Output operation
+ */
+#define NFC_OUTPUT	0x8
+
+/*
+ * Set INT to 0, FD0 to 010, rest to 0 in NFC_CONFIG2 Register for Read ID
+ * operation
+ */
+#define NFC_ID		0x10
+
+/*
+ * Set INT to 0, FDO to 100, rest to 0 in NFC_CONFIG2 Register for Read
+ * Status operation
+ */
+#define NFC_STATUS	0x20
+
+/*
+ * Set INT to 1, rest to 0 in NFC_CONFIG2 Register for Read Status
+ * operation
+ */
+#define NFC_INT		0x8000
+
+#define NFC_SP_EN	(1 << 2)
+#define NFC_ECC_EN	(1 << 3)
+#define NFC_INT_MSK	(1 << 4)
+#define NFC_BIG		(1 << 5)
+#define NFC_RST		(1 << 6)
+#define NFC_CE		(1 << 7)
+#define NFC_ONE_CYCLE	(1 << 8)
+
+#endif /* __FSL_NFC_H */
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) ;
+}