[PATCH] NAND: Add 16bit NAND support for the NDFC

[Alex Waterman]

This patch adds support for 16 bit NAND devices attached to the
NDFC on ppc4xx processors. Two config entries were added:

  CONFIG_SYS_NDFC_16        - Setting this tells the NDFC that a
			      16 bit device is attached.
  CONFIG_SYS_NDFC_EBC0_CFG  - This is for the External Bus
			      Controller configuration register.

Also, a new ndfc_read_byte() function was added which does not
first convert the data to little endian.

The NAND SPL was also modified to do 16bit bad block testing
when a 16 bit chip is being used.

Signed-off-by: Alex Waterman <awaterman at dawning.com>
---
 README                  |    8 ++++++++
 drivers/mtd/nand/ndfc.c |   33 +++++++++++++++++++++++++++++----
 nand_spl/nand_boot.c    |   11 ++++++++---
 3 files changed, 45 insertions(+), 7 deletions(-)

Changes for v2:
   - Changes dynamic checking of chip options field to a compile time
     check.
Changes for v3:
   - Revert back to dynamic checking of chip->options in the nand_spl
     code.

Note:
  For now I just went back to dynamic checking in the nand_spl code since
that is easeir. I think its worth using a preprocessor directive to do
this instead but that would require some more thought. Maybe when the next
release is out I can look into that but for now I don't have as much time
as I would
like :(.

Sorry about that, silly typo I missed because I compiled a RAM boot version
of my code not a NAND version. Whoops. This new patch now passes 

$ MAKEALL -v amcc

diff --git a/README b/README
index 8bb9c8d..9d33a2e 100644
--- a/README
+++ b/README
@@ -2918,6 +2918,14 @@ Low Level (hardware related) configuration options:
 - CONFIG_SYS_SRIOn_MEM_SIZE:
 		Size of SRIO port 'n' memory region
 
+- CONFIG_SYS_NDFC_16
+		Defined to tell the NDFC that the NAND chip is using a
+		16 bit bus.
+
+- CONFIG_SYS_NDFC_EBC0_CFG
+		Sets the EBC0_CFG register for the NDFC. If not defined
+		a default value will be used.
+
 - CONFIG_SPD_EEPROM
 		Get DDR timing information from an I2C EEPROM. Common
 		with pluggable memory modules such as SODIMMs
diff --git a/drivers/mtd/nand/ndfc.c b/drivers/mtd/nand/ndfc.c
index 0729e0c..6ebbb5e 100644
--- a/drivers/mtd/nand/ndfc.c
+++ b/drivers/mtd/nand/ndfc.c
@@ -37,6 +37,13 @@
 #include <asm/io.h>
 #include <asm/ppc4xx.h>
 
+#ifndef CONFIG_SYS_NAND_BCR
+#define CONFIG_SYS_NAND_BCR 0x80002222
+#endif
+#ifndef CONFIG_SYS_NDFC_EBC0_CFG
+#define CONFIG_SYS_NDFC_EBC0_CFG 0xb8400000
+#endif
+
 /*
  * We need to store the info, which chip-select (CS) is used for the
  * chip number. For example on Sequoia NAND chip #0 uses
@@ -140,12 +147,25 @@ static int ndfc_verify_buf(struct mtd_info *mtdinfo, const uint8_t *buf, int len
 
 	return 0;
 }
-#endif /* #ifndef CONFIG_NAND_SPL */
 
-#ifndef CONFIG_SYS_NAND_BCR
-#define CONFIG_SYS_NAND_BCR 0x80002222
+/*
+ * Read a byte from the NDFC.
+ */
+static uint8_t ndfc_read_byte(struct mtd_info *mtd)
+{
+
+	struct nand_chip *chip = mtd->priv;
+
+#ifdef CONFIG_SYS_NDFC_16BIT
+	return (uint8_t) readw(chip->IO_ADDR_R);
+#else
+	return readb(chip->IO_ADDR_R);
 #endif
 
+}
+
+#endif /* #ifndef CONFIG_NAND_SPL */
+
 void board_nand_select_device(struct nand_chip *nand, int chip)
 {
 	/*
@@ -198,16 +218,21 @@ int board_nand_init(struct nand_chip *nand)
 	nand->ecc.bytes = 3;
 	nand->select_chip = ndfc_select_chip;
 
+#ifdef CONFIG_SYS_NDFC_16BIT
+	nand->options |= NAND_BUSWIDTH_16;
+#endif
+
 #ifndef CONFIG_NAND_SPL
 	nand->write_buf  = ndfc_write_buf;
 	nand->verify_buf = ndfc_verify_buf;
+	nand->read_byte = ndfc_read_byte;
 
 	chip++;
 #else
 	/*
 	 * Setup EBC (CS0 only right now)
 	 */
-	mtebc(EBC0_CFG, 0xb8400000);
+	mtebc(EBC0_CFG, CONFIG_SYS_NDFC_EBC0_CFG);
 
 	mtebc(PB0CR, CONFIG_SYS_EBC_PB0CR);
 	mtebc(PB0AP, CONFIG_SYS_EBC_PB0AP);
diff --git a/nand_spl/nand_boot.c b/nand_spl/nand_boot.c
index 9545a9a..4683c7c 100644
--- a/nand_spl/nand_boot.c
+++ b/nand_spl/nand_boot.c
@@ -122,10 +122,15 @@ static int nand_is_bad_block(struct mtd_info *mtd, int block)
 	nand_command(mtd, block, 0, CONFIG_SYS_NAND_BAD_BLOCK_POS, NAND_CMD_READOOB);
 
 	/*
-	 * Read one byte
+	 * Read one byte (or two if it's a 16 bit chip).
 	 */
-	if (readb(this->IO_ADDR_R) != 0xff)
-		return 1;
+	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;
 }
-- 
1.7.4.4

-- 
Alex Waterman
Computer Engineer
Phone: 215-896-4920
Email: awaterman at dawning.com