Re: [PATCH] i.MX6: bbu: Barebox update support for NAND.

[Sascha Hauer <s.hauer@pengutronix.de>]

Hi Dmitry,

On Wed, Mar 12, 2014 at 10:54:11AM +0300, Dmitry Lavnikevich wrote:
> This patch implements updating barebox on i.MX6 NAND. In userspace
> similar task is performed by freescale kobs-ng utility.
> To use this bbu profile nand handler should be registered in board
> code with 'imx6_bbu_internal_nand_register_handler' function.

I have the very same patch in the queue, it seems we have duplicated
some work. As this version has some shortcomings I'll post my version as
an alternative implementation. Also I'll try your version on a board I
have here on which my version doesn't work (which is the reason I
haven't posted my patch yet)

> +static int erase_part(struct mtd_info *mtd)
> +{
> +	loff_t ofs;
> +	int ret = 0;
> +	struct erase_info erase_opts = {
> +		.mtd = mtd,
> +		.addr = 0,
> +		.len = mtd->erasesize,
> +		.callback = NULL,
> +	};
> +
> +	for (ofs = 0; ofs < mtd->size; ofs += mtd->erasesize) {
> +		ret = mtd_block_isbad(mtd, ofs);
> +		if (ret > 0) {
> +			printf("Warning: bad block at 0x%08llx. Skipping\n",
> +				   ofs);
> +			continue;

This is not worth issueing a warning. Bad blocks just happen.

> +		} else if (ret < 0) {
> +			printf("Error: checking bad block at 0x%llx failed\n",
> +				   ofs);
> +			ret = 1;
> +			goto err;
> +		}
> +
> +		erase_opts.addr = ofs;
> +		ret = mtd->erase(mtd, &erase_opts);

You should use mtd_erase and friends rather than dereferencing struct
mtd_info.

> +	buf = malloc(mtd->erasesize);
> +	if (!buf) {
> +		ret = -ENOMEM;
> +		goto err_out;
> +	}
> +
> +	image = read_imagefile(mtd, data->imagefile, &fw_size);
> +	if (!image) {
> +		ret = -errno;
> +		goto err_out1;
> +	}

No Need to read the image, data->image contains a pointer to it.

> +
> +	search_area_size_in_bytes =
> +		(1 << SEARCH_EXPONENT) * PAGES_PER_STRIDE * mtd->writesize;
> +	max_boot_stream_in_bytes =
> +		(mtd->size - search_area_size_in_bytes * 2) / 2;
> +
> +	fw1_offset = 2 * search_area_size_in_bytes;
> +	fw2_offset = fw1_offset + max_boot_stream_in_bytes;
> +
> +	fcb = create_fcb(mtd, buf, fw1_offset, fw_size, fw2_offset);
> +	if (IS_ERR(fcb)) {
> +		printf("Failed to initialize FCB: %ld\n", PTR_ERR(fcb));
> +		ret = PTR_ERR(fcb);
> +		goto err_out2;
> +	}
> +	encode_hamming_13_8(fcb, (void *)fcb + 512, 512);
> +
> +	dbbt = create_dbbt(mtd, &bbtn);
> +	if (!dbbt)
> +		goto err_out2;
> +
> +	erase_part(mtd);

Error checking?

> +
> +	block = bcb_cdev->offset;
> +	for (fcb_written = 0; fcb_written < 4; fcb_written++) {
> +
> +		if (nand_isbad_bbt(mtd, block, false))
> +			continue;
> +
> +		ret = write_fcb(mtd, buf, block);
> +		if (ret) {
> +			printf("Failed to write FCB to block %u\n", block);
> +			goto err_out2;
> +		}
> +		block += mtd->erasesize;
> +	}
> +	ret = fcb_written ? 0 : -ENOSPC;
> +	if (ret)
> +		goto err_out2;
> +
> +	stride_size_in_bytes = PAGES_PER_STRIDE * mtd->writesize;
> +	block = SEARCH_AREA_SIZE_IN_PAGES * mtd->writesize;
> +	i = 0;
> +	while (i < SEARCH_AREA_SIZE_IN_STRIDES) {
> +		ret = write_dbbt(mtd, dbbt, buf, block, sizeof(*dbbt));
> +		if (ret)
> +			goto err_out2;
> +
> +		block += stride_size_in_bytes;
> +		i++;
> +	}
> +
> +	block = SEARCH_AREA_SIZE_IN_PAGES * mtd->writesize + 4 * mtd->writesize;
> +	i = 0;
> +	while (i < SEARCH_AREA_SIZE_IN_STRIDES) {
> +		ret = write_bbtn(mtd, bbtn, buf, block, sizeof(*bbtn));
> +		if (ret)
> +			goto err_out2;
> +
> +		block += stride_size_in_bytes;
> +		i++;
> +	}
> +
> +	ret = write_image(mtd, image, fw1_offset, fw_size);
> +	if (ret)
> +		goto err_out2;
> +	ret = write_image(mtd, image, fw2_offset, fw_size);
> +	if (ret)
> +		goto err_out2;

This doesn't seem to take bad blocks into account. What happens when the
first firmware image gets bigger due to bad blocks? It will be
overwritten by the 2nd image.

Sascha

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