am33xx_spl_bch: simple SPL nand loader for AM33XX

AM33XX with BCH8 can't work with nand_spl_simple correctly
because custom read_page implementation is required for proper
syndrome generation.

This simple driver mostly duplicates nand_spl_simple but has
nand_read_page changed to suit our needs.

Signed-off-by: Ilya Yanok <ilya.yanok@cogentembedded.com>

drivers/mtd/nand/Makefile

@@ -30,6 +30,7 @@ ifdef CONFIG_SPL_BUILD
 ifdef CONFIG_SPL_NAND_SIMPLE
 COBJS-y += nand_spl_simple.o
 endif
+COBJS-$(CONFIG_SPL_NAND_AM33XX_BCH) += am335x_spl_bch.o
 ifdef CONFIG_SPL_NAND_LOAD
 COBJS-y	+= nand_spl_load.o
 endif

drivers/mtd/nand/am335x_spl_bch.c

@@ -0,0 +1,238 @@
+/*
+ * (C) Copyright 2012
+ * Konstantin Kozhevnikov, Cogent Embedded
+ *
+ * based on nand_spl_simple code
+ *
+ * (C) Copyright 2006-2008
+ * 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.
+ */
+
+#include <common.h>
+#include <nand.h>
+#include <asm/io.h>
+#include <linux/mtd/nand_ecc.h>
+
+static int nand_ecc_pos[] = CONFIG_SYS_NAND_ECCPOS;
+static nand_info_t mtd;
+static struct nand_chip nand_chip;
+
+#define ECCSTEPS	(CONFIG_SYS_NAND_PAGE_SIZE / \
+					CONFIG_SYS_NAND_ECCSIZE)
+#define ECCTOTAL	(ECCSTEPS * CONFIG_SYS_NAND_ECCBYTES)
+
+
+/*
+ * NAND command for large page NAND devices (2k)
+ */
+static int nand_command(int block, int page, uint32_t offs,
+	u8 cmd)
+{
+	struct nand_chip *this = mtd.priv;
+	int page_addr = page + block * CONFIG_SYS_NAND_PAGE_COUNT;
+	void (*hwctrl)(struct mtd_info *mtd, int cmd,
+			unsigned int ctrl) = this->cmd_ctrl;
+
+	while (!this->dev_ready(&mtd))
+		;
+
+	/* Emulate NAND_CMD_READOOB */
+	if (cmd == NAND_CMD_READOOB) {
+		offs += CONFIG_SYS_NAND_PAGE_SIZE;
+		cmd = NAND_CMD_READ0;
+	}
+
+	/* Begin command latch cycle */
+	hwctrl(&mtd, cmd, NAND_CTRL_CLE | NAND_CTRL_CHANGE);
+
+	if (cmd == NAND_CMD_RESET) {
+		hwctrl(&mtd, NAND_CMD_NONE, NAND_NCE | NAND_CTRL_CHANGE);
+		while (!this->dev_ready(&mtd))
+			;
+		return 0;
+	}
+
+	/* Shift the offset from byte addressing to word addressing. */
+	if (this->options & NAND_BUSWIDTH_16)
+		offs >>= 1;
+
+	/* Set ALE and clear CLE to start address cycle */
+	/* Column address */
+	hwctrl(&mtd, offs & 0xff,
+		       NAND_CTRL_ALE | NAND_CTRL_CHANGE); /* A[7:0] */
+	hwctrl(&mtd, (offs >> 8) & 0xff, NAND_CTRL_ALE); /* A[11:9] */
+	/* Row address */
+	hwctrl(&mtd, (page_addr & 0xff), NAND_CTRL_ALE); /* A[19:12] */
+	hwctrl(&mtd, ((page_addr >> 8) & 0xff),
+		       NAND_CTRL_ALE); /* A[27:20] */
+#ifdef CONFIG_SYS_NAND_5_ADDR_CYCLE
+	/* One more address cycle for devices > 128MiB */
+	hwctrl(&mtd, (page_addr >> 16) & 0x0f,
+		       NAND_CTRL_ALE); /* A[31:28] */
+#endif
+	hwctrl(&mtd, NAND_CMD_NONE, NAND_NCE | NAND_CTRL_CHANGE);
+
+	if (cmd == NAND_CMD_READ0) {
+		/* Latch in address */
+		hwctrl(&mtd, NAND_CMD_READSTART,
+			   NAND_CTRL_CLE | NAND_CTRL_CHANGE);
+		hwctrl(&mtd, NAND_CMD_NONE, NAND_NCE | NAND_CTRL_CHANGE);
+
+		/*
+		 * Wait a while for the data to be ready
+		 */
+		while (!this->dev_ready(&mtd))
+			;
+	} else if (cmd == NAND_CMD_RNDOUT) {
+		hwctrl(&mtd, NAND_CMD_RNDOUTSTART, NAND_CTRL_CLE |
+					NAND_CTRL_CHANGE);
+		hwctrl(&mtd, NAND_CMD_NONE, NAND_NCE | NAND_CTRL_CHANGE);
+	}
+
+	return 0;
+}
+
+static int nand_is_bad_block(int block)
+{
+	struct nand_chip *this = mtd.priv;
+
+	nand_command(block, 0, CONFIG_SYS_NAND_BAD_BLOCK_POS,
+		NAND_CMD_READOOB);
+
+	/*
+	 * Read one byte (or two if it's a 16 bit chip).
+	 */
+	if (this->options & NAND_BUSWIDTH_16) {
+		if (readw(this->IO_ADDR_R) != 0xffff)
+			return 1;
+	} else {
+		if (readb(this->IO_ADDR_R) != 0xff)
+			return 1;
+	}
+
+	return 0;
+}
+
+static int nand_read_page(int block, int page, void *dst)
+{
+	struct nand_chip *this = mtd.priv;
+	u_char ecc_calc[ECCTOTAL];
+	u_char ecc_code[ECCTOTAL];
+	u_char oob_data[CONFIG_SYS_NAND_OOBSIZE];
+	int i;
+	int eccsize = CONFIG_SYS_NAND_ECCSIZE;
+	int eccbytes = CONFIG_SYS_NAND_ECCBYTES;
+	int eccsteps = ECCSTEPS;
+	uint8_t *p = dst;
+	uint32_t data_pos = 0;
+	uint8_t *oob = &oob_data[0] + nand_ecc_pos[0];
+	uint32_t oob_pos = eccsize * eccsteps + nand_ecc_pos[0];
+
+	nand_command(block, page, 0, NAND_CMD_READ0);
+
+	for (i = 0; eccsteps; eccsteps--, i += eccbytes, p += eccsize) {
+		this->ecc.hwctl(&mtd, NAND_ECC_READ);
+		nand_command(block, page, data_pos, NAND_CMD_RNDOUT);
+
+		this->read_buf(&mtd, p, eccsize);
+
+		nand_command(block, page, oob_pos, NAND_CMD_RNDOUT);
+
+		this->read_buf(&mtd, oob, eccbytes);
+		this->ecc.calculate(&mtd, p, &ecc_calc[i]);
+
+		data_pos += eccsize;
+		oob_pos += eccbytes;
+		oob += eccbytes;
+	}
+
+	/* Pick the ECC bytes out of the oob data */
+	for (i = 0; i < ECCTOTAL; i++)
+		ecc_code[i] = oob_data[nand_ecc_pos[i]];
+
+	eccsteps = ECCSTEPS;
+	p = dst;
+
+	for (i = 0 ; eccsteps; eccsteps--, i += eccbytes, p += eccsize) {
+		/* No chance to do something with the possible error message
+		 * from correct_data(). We just hope that all possible errors
+		 * are corrected by this routine.
+		 */
+		this->ecc.correct(&mtd, p, &ecc_code[i], &ecc_calc[i]);
+	}
+
+	return 0;
+}
+
+int nand_spl_load_image(uint32_t offs, unsigned int size, void *dst)
+{
+	unsigned int block, lastblock;
+	unsigned int page;
+
+	/*
+	 * offs has to be aligned to a page address!
+	 */
+	block = offs / CONFIG_SYS_NAND_BLOCK_SIZE;
+	lastblock = (offs + size - 1) / CONFIG_SYS_NAND_BLOCK_SIZE;
+	page = (offs % CONFIG_SYS_NAND_BLOCK_SIZE) / CONFIG_SYS_NAND_PAGE_SIZE;
+
+	while (block <= lastblock) {
+		if (!nand_is_bad_block(block)) {
+			/*
+			 * Skip bad blocks
+			 */
+			while (page < CONFIG_SYS_NAND_PAGE_COUNT) {
+				nand_read_page(block, page, dst);
+				dst += CONFIG_SYS_NAND_PAGE_SIZE;
+				page++;
+			}
+
+			page = 0;
+		} else {
+			lastblock++;
+		}
+
+		block++;
+	}
+
+	return 0;
+}
+
+/* nand_init() - initialize data to make nand usable by SPL */
+void nand_init(void)
+{
+	/*
+	 * Init board specific nand support
+	 */
+	mtd.priv = &nand_chip;
+	nand_chip.IO_ADDR_R = nand_chip.IO_ADDR_W =
+		(void  __iomem *)CONFIG_SYS_NAND_BASE;
+	board_nand_init(&nand_chip);
+
+	if (nand_chip.select_chip)
+		nand_chip.select_chip(&mtd, 0);
+
+	/* NAND chip may require reset after power-on */
+	nand_command(0, 0, 0, NAND_CMD_RESET);
+}
+
+/* Unselect after operation */
+void nand_deselect(void)
+{
+	if (nand_chip.select_chip)
+		nand_chip.select_chip(&mtd, -1);
+}