spl/nand: config symbol documentation

Document parameters used for specifying the NAND image to be loaded.

Also fix the definition of CONFIG_SPL_NAND_SIMPLE -- it's only
nand_spl_simple.c, not the entire nand directory.  The word "simple" is
there for a reason.  :-)

Signed-off-by: Scott Wood <scottwood@freescale.com>
---
v2: updated for makefile changes earlier in patchset

README

@@ -2727,7 +2727,8 @@ FIT uImage format:
 		Include standard software ECC in the SPL
 
 		CONFIG_SPL_NAND_SIMPLE
-		Support for drivers/mtd/nand/libnand.o in SPL binary
+		Support for NAND boot using simple NAND drivers that
+		expose the cmd_ctrl() interface.
 
 		CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
 		CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
@@ -2735,15 +2736,19 @@ FIT uImage format:
 		CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
 		CONFIG_SYS_NAND_ECCBYTES
 		Defines the size and behavior of the NAND that SPL uses
-		to read U-Boot with CONFIG_SPL_NAND_SIMPLE
+		to read U-Boot
 
 		CONFIG_SYS_NAND_U_BOOT_OFFS
-		Location in NAND for CONFIG_SPL_NAND_SIMPLE to read U-Boot
-		from.
+		Location in NAND to read U-Boot from
+
+		CONFIG_SYS_NAND_U_BOOT_DST
+		Location in memory to load U-Boot to
+
+		CONFIG_SYS_NAND_U_BOOT_SIZE
+		Size of image to load
 
 		CONFIG_SYS_NAND_U_BOOT_START
-		Location in memory for CONFIG_SPL_NAND_SIMPLE to load U-Boot
-		to.
+		Entry point in loaded image to jump to
 
 		CONFIG_SYS_NAND_HW_ECC_OOBFIRST
 		Define this if you need to first read the OOB and then the

drivers/mtd/nand/Makefile

@@ -78,6 +78,10 @@ COBJS-$(CONFIG_TEGRA_NAND) += tegra_nand.o
 COBJS-$(CONFIG_NAND_OMAP_GPMC) += omap_gpmc.o
 COBJS-$(CONFIG_NAND_PLAT) += nand_plat.o
 
+else  # minimal SPL drivers
+
+COBJS-$(CONFIG_NAND_FSL_ELBC) += fsl_elbc_spl.o
+
 endif # drivers
 endif # nand
 

drivers/mtd/nand/fsl_elbc_spl.c

@@ -0,0 +1,168 @@
+/*
+ * NAND boot for Freescale Enhanced Local Bus Controller, Flash Control Machine
+ *
+ * (C) Copyright 2006-2008
+ * Stefan Roese, DENX Software Engineering, sr@denx.de.
+ *
+ * Copyright (c) 2008 Freescale Semiconductor, Inc.
+ * Author: Scott Wood <scottwood@freescale.com>
+ *
+ * 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 <asm/io.h>
+#include <asm/fsl_lbc.h>
+#include <nand.h>
+
+#define WINDOW_SIZE 8192
+
+static void nand_wait(void)
+{
+	fsl_lbc_t *regs = LBC_BASE_ADDR;
+
+	for (;;) {
+		uint32_t status = in_be32(&regs->ltesr);
+
+		if (status == 1)
+			return;
+
+		if (status & 1) {
+			puts("read failed (ltesr)\n");
+			for (;;);
+		}
+	}
+}
+
+static int nand_load_image(uint32_t offs, unsigned int uboot_size, void *vdst)
+{
+	fsl_lbc_t *regs = LBC_BASE_ADDR;
+	uchar *buf = (uchar *)CONFIG_SYS_NAND_BASE;
+	const int large = CONFIG_SYS_NAND_OR_PRELIM & OR_FCM_PGS;
+	const int block_shift = large ? 17 : 14;
+	const int block_size = 1 << block_shift;
+	const int page_size = large ? 2048 : 512;
+	const int bad_marker = large ? page_size + 0 : page_size + 5;
+	int fmr = (15 << FMR_CWTO_SHIFT) | (2 << FMR_AL_SHIFT) | 2;
+	int pos = 0;
+	char *dst = vdst;
+
+	if (offs & (block_size - 1)) {
+		puts("bad offset\n");
+		for (;;);
+	}
+
+	if (large) {
+		fmr |= FMR_ECCM;
+		out_be32(&regs->fcr, (NAND_CMD_READ0 << FCR_CMD0_SHIFT) |
+		                     (NAND_CMD_READSTART << FCR_CMD1_SHIFT));
+		out_be32(&regs->fir,
+		         (FIR_OP_CW0 << FIR_OP0_SHIFT) |
+		         (FIR_OP_CA  << FIR_OP1_SHIFT) |
+		         (FIR_OP_PA  << FIR_OP2_SHIFT) |
+		         (FIR_OP_CW1 << FIR_OP3_SHIFT) |
+		         (FIR_OP_RBW << FIR_OP4_SHIFT));
+	} else {
+		out_be32(&regs->fcr, NAND_CMD_READ0 << FCR_CMD0_SHIFT);
+		out_be32(&regs->fir,
+		         (FIR_OP_CW0 << FIR_OP0_SHIFT) |
+		         (FIR_OP_CA  << FIR_OP1_SHIFT) |
+		         (FIR_OP_PA  << FIR_OP2_SHIFT) |
+		         (FIR_OP_RBW << FIR_OP3_SHIFT));
+	}
+
+	out_be32(&regs->fbcr, 0);
+	clrsetbits_be32(&regs->bank[0].br, BR_DECC, BR_DECC_CHK_GEN);
+
+	while (pos < uboot_size) {
+		int i = 0;
+		out_be32(&regs->fbar, offs >> block_shift);
+
+		do {
+			int j;
+			unsigned int page_offs = (offs & (block_size - 1)) << 1;
+
+			out_be32(&regs->ltesr, ~0);
+			out_be32(&regs->lteatr, 0);
+			out_be32(&regs->fpar, page_offs);
+			out_be32(&regs->fmr, fmr);
+			out_be32(&regs->lsor, 0);
+			nand_wait();
+
+			page_offs %= WINDOW_SIZE;
+
+			/*
+			 * If either of the first two pages are marked bad,
+			 * continue to the next block.
+			 */
+			if (i++ < 2 && buf[page_offs + bad_marker] != 0xff) {
+				puts("skipping\n");
+				offs = (offs + block_size) & ~(block_size - 1);
+				pos &= ~(block_size - 1);
+				break;
+			}
+
+			for (j = 0; j < page_size; j++)
+				dst[pos + j] = buf[page_offs + j];
+
+			pos += page_size;
+			offs += page_size;
+		} while ((offs & (block_size - 1)) && (pos < uboot_size));
+	}
+
+	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);
+	/*
+	 * Load U-Boot image from NAND into RAM
+	 */
+	nand_load_image(CONFIG_SYS_NAND_U_BOOT_OFFS,
+			CONFIG_SYS_NAND_U_BOOT_SIZE,
+			(void *)CONFIG_SYS_NAND_U_BOOT_DST);
+
+#ifdef CONFIG_NAND_ENV_DST
+	nand_load_image(CONFIG_ENV_OFFSET, CONFIG_ENV_SIZE,
+			(void *)CONFIG_NAND_ENV_DST);
+
+#ifdef CONFIG_ENV_OFFSET_REDUND
+	nand_load_image(CONFIG_ENV_OFFSET_REDUND, CONFIG_ENV_SIZE,
+			(void *)CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE);
+#endif
+#endif
+
+#ifdef CONFIG_SPL_FLUSH_IMAGE
+	/*
+	 * Clean d-cache and invalidate i-cache, to
+	 * make sure that no stale data is executed.
+	 */
+	flush_cache(CONFIG_SYS_NAND_U_BOOT_DST, CONFIG_SYS_NAND_U_BOOT_SIZE);
+#endif
+
+	puts("transfering control\n");
+	/*
+	 * Jump to U-Boot image
+	 */
+	uboot = (void *)CONFIG_SYS_NAND_U_BOOT_START;
+	(*uboot)();
+}