Linux/AM3352: NAND boot fails

Hi,

The "CCCC..." printout from the console does not mean "sysboot mode error or there is no MLO in nand flash". This is simply the sync character for UART boot.

What is the page size/OOB size of your NAND? What ECC are you using? How is the NAND connected?

Please read section 26.1.8.4 of the AM335x TRM Rev. P and check if you meet all the requirements.

hello Biser

The page of my nand flash is 2048 bytes, and the OOB is 128 bytes, ECC is BCH8, following message is from nand flash datasheet:

– Input / Output Bus Width: 8 bits

– Page size:

– ×8:

2 Gb / 4 Gb: (2048 + 128) bytes; 128-byte spare area

This is the schematic diagram:

I used to modify uboot code with 128 bytes:

am335x_evm.h:

#define CONFIG_SYS_NAND_OOBSIZE 128//64

omap_gpmc.h:

#define GPMC_NAND_HW_BCH8_ECC_LAYOUT {\
.eccbytes = 56,\
.eccpos = {2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,\
16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27,\
28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39,\
40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51,\
52, 53, 54, 55, 56, 57},\
.oobfree = {\
{.offset = 58,\
.length = 70/*6*/ } } \
}

in drivers\mtd\nand\nand_base.c file, modify nand_get_flash_type function:

/* Calc blocksize */
mtd->erasesize = (128 * 1024) <<
(((extid >> 1) & 0x04) | (extid & 0x03));
busw = 0;
} else {
/* Calc pagesize */
mtd->writesize = 1024 << (extid & 0x03);
extid >>= 2;
/* Calc oobsize */
//mtd->oobsize = (8 << (extid & 0x01)) *
// (mtd->writesize >> 9);
mtd->oobsize = 128;            //force oob size with 128
extid >>= 2;
/* Calc blocksize. Blocksize is multiples of 64KiB */
mtd->erasesize = (64 * 1024) << (extid & 0x03);
extid >>= 2;
/* Get buswidth information */
busw = (extid & 0x01) ? NAND_BUSWIDTH_16 : 0;
}

with those modification, there is no effect.

I use u-boot-2013.01.01-psp06.00.00.00

hello Biser

How does the Rom Code recognize the OOB size? Is it by reading ID? 

hello Biser

I use a new SDK: am335x-evm-linux-sdk-arago-src-04.00.00.04.tar

The function of starting from nand is ok now, but during kernel start up, there is an error with [    2.102321] omap2-nand omap2-nand.0: uncorrectable bit-flips found, I have checked the kernel code, it found an error_uncorrectable:

in file drivers\mtd\nand\omap2.c:

for (i = 0; i < eccsteps; i++) {

if (err_vec[i].error_uncorrectable) {

dev_err(&info->pdev->dev,

"uncorrectable bit-flips found\n");

err = -EBADMSG;

}

and in the file drivers/mtd/nand/omap_elm.c, err_vec[i].error_uncorrectable will be set to true when read ELM_LOCATION_STATUS error in elm_error_correction function:

static void elm_error_correction(struct elm_info *info,
struct elm_errorvec *err_vec)
{
int i, j, errors = 0;
int offset;
u32 reg_val;

for (i = 0; i < info->ecc_steps; i++) {

/* Check error reported */
if (err_vec[i].error_reported) {
offset = ELM_LOCATION_STATUS + ERROR_LOCATION_SIZE * i;
reg_val = elm_read_reg(info, offset);

/* Check correctable error or not */
if (reg_val & ECC_CORRECTABLE_MASK) {
offset = ELM_ERROR_LOCATION_0 +
ERROR_LOCATION_SIZE * i;

/* Read count of correctable errors */
err_vec[i].error_count = reg_val &
ECC_NB_ERRORS_MASK;

/* Update the error locations in error vector */
for (j = 0; j < err_vec[i].error_count; j++) {

reg_val = elm_read_reg(info, offset);
err_vec[i].error_loc[j] = reg_val &
ECC_ERROR_LOCATION_MASK;

/* Update error location register */
offset += 4;
}

errors += err_vec[i].error_count;
} else {
err_vec[i].error_uncorrectable = true;
}

/* Clearing interrupts for processed error vectors */
elm_write_reg(info, ELM_IRQSTATUS, BIT(i));

/* Disable page mode */
elm_configure_page_mode(info, i, false);
}
}
}

why my ELM_LOCATION_STATUS register error?  How can I solve this problem?

This is a different question. Please open an new thread for it.