[U-Boot] [PATCH 4/7] tools: sunxi: Add spl image builder

[Boris Brezillon <boris.brezillon@free-electrons.com>]

On Tue,  8 Nov 2016 17:21:14 +0100
Maxime Ripard <maxime.ripard@free-electrons.com> wrote:

> This program generates raw SPL images that can be flashed on the NAND with
> the ECC and randomizer properly set up.
> 

Maybe you should mention that this file has been copied from the
sunxi-tools project.

Otherwise,

Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>

> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> ---
>  tools/.gitignore                |    1 +-
>  tools/Makefile                  |    1 +-
>  tools/sunxi-spl-image-builder.c | 1113 ++++++++++++++++++++++++++++++++-
>  3 files changed, 1115 insertions(+), 0 deletions(-)
>  create mode 100644 tools/sunxi-spl-image-builder.c
> 
> diff --git a/tools/.gitignore b/tools/.gitignore
> index cb1e722d4575..16574467544c 100644
> --- a/tools/.gitignore
> +++ b/tools/.gitignore
> @@ -15,6 +15,7 @@
>  /mkexynosspl
>  /mxsboot
>  /mksunxiboot
> +/sunxi-spl-image-builder
>  /ncb
>  /proftool
>  /relocate-rela
> diff --git a/tools/Makefile b/tools/Makefile
> index 400588cf0f5c..dfeeb23484ce 100644
> --- a/tools/Makefile
> +++ b/tools/Makefile
> @@ -171,6 +171,7 @@ hostprogs-$(CONFIG_MX28) += mxsboot
>  HOSTCFLAGS_mxsboot.o := -pedantic
>  
>  hostprogs-$(CONFIG_ARCH_SUNXI) += mksunxiboot
> +hostprogs-$(CONFIG_ARCH_SUNXI) += sunxi-spl-image-builder
>  
>  hostprogs-$(CONFIG_NETCONSOLE) += ncb
>  hostprogs-$(CONFIG_SHA1_CHECK_UB_IMG) += ubsha1
> diff --git a/tools/sunxi-spl-image-builder.c b/tools/sunxi-spl-image-builder.c
> new file mode 100644
> index 000000000000..0f915eb2bdf5
> --- /dev/null
> +++ b/tools/sunxi-spl-image-builder.c
> @@ -0,0 +1,1113 @@
> +/*
> + * Generic binary BCH encoding/decoding library
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License version 2 as published by
> + * the Free Software Foundation.
> + *
> + * 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., 51
> + * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
> + *
> + * For the BCH implementation:
> + *
> + * Copyright ? 2011 Parrot S.A.
> + *
> + * Author: Ivan Djelic <ivan.djelic@parrot.com>
> + *
> + * See also:
> + * http://lxr.free-electrons.com/source/lib/bch.c
> + *
> + * For the randomizer and image builder implementation:
> + *
> + * Copyright ? 2016 NextThing Co.
> + * Copyright ? 2016 Free Electrons
> + *
> + * Author: Boris Brezillon <boris.brezillon@free-electrons.com>
> + *
> + */
> +
> +#include <stdint.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <stdio.h>
> +#include <linux/kernel.h>
> +#include <linux/errno.h>
> +#include <asm/byteorder.h>
> +#include <endian.h>
> +#include <getopt.h>
> +#include <version.h>
> +
> +#if defined(CONFIG_BCH_CONST_PARAMS)
> +#define GF_M(_p)               (CONFIG_BCH_CONST_M)
> +#define GF_T(_p)               (CONFIG_BCH_CONST_T)
> +#define GF_N(_p)               ((1 << (CONFIG_BCH_CONST_M))-1)
> +#else
> +#define GF_M(_p)               ((_p)->m)
> +#define GF_T(_p)               ((_p)->t)
> +#define GF_N(_p)               ((_p)->n)
> +#endif
> +
> +#define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
> +
> +#define BCH_ECC_WORDS(_p)      DIV_ROUND_UP(GF_M(_p)*GF_T(_p), 32)
> +#define BCH_ECC_BYTES(_p)      DIV_ROUND_UP(GF_M(_p)*GF_T(_p), 8)
> +
> +#ifndef dbg
> +#define dbg(_fmt, args...)     do {} while (0)
> +#endif
> +
> +#define cpu_to_be32 htobe32
> +#define kfree free
> +#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
> +
> +#define BCH_PRIMITIVE_POLY	0x5803
> +
> +struct image_info {
> +	int ecc_strength;
> +	int ecc_step_size;
> +	int page_size;
> +	int oob_size;
> +	int usable_page_size;
> +	int eraseblock_size;
> +	int scramble;
> +	int boot0;
> +	off_t offset;
> +	const char *source;
> +	const char *dest;
> +};
> +
> +/**
> + * struct bch_control - BCH control structure
> + * @m:          Galois field order
> + * @n:          maximum codeword size in bits (= 2^m-1)
> + * @t:          error correction capability in bits
> + * @ecc_bits:   ecc exact size in bits, i.e. generator polynomial degree (<=m*t)
> + * @ecc_bytes:  ecc max size (m*t bits) in bytes
> + * @a_pow_tab:  Galois field GF(2^m) exponentiation lookup table
> + * @a_log_tab:  Galois field GF(2^m) log lookup table
> + * @mod8_tab:   remainder generator polynomial lookup tables
> + * @ecc_buf:    ecc parity words buffer
> + * @ecc_buf2:   ecc parity words buffer
> + * @xi_tab:     GF(2^m) base for solving degree 2 polynomial roots
> + * @syn:        syndrome buffer
> + * @cache:      log-based polynomial representation buffer
> + * @elp:        error locator polynomial
> + * @poly_2t:    temporary polynomials of degree 2t
> + */
> +struct bch_control {
> +	unsigned int    m;
> +	unsigned int    n;
> +	unsigned int    t;
> +	unsigned int    ecc_bits;
> +	unsigned int    ecc_bytes;
> +/* private: */
> +	uint16_t       *a_pow_tab;
> +	uint16_t       *a_log_tab;
> +	uint32_t       *mod8_tab;
> +	uint32_t       *ecc_buf;
> +	uint32_t       *ecc_buf2;
> +	unsigned int   *xi_tab;
> +	unsigned int   *syn;
> +	int            *cache;
> +	struct gf_poly *elp;
> +	struct gf_poly *poly_2t[4];
> +};
> +
> +static int fls(int x)
> +{
> +	int r = 32;
> +
> +	if (!x)
> +		return 0;
> +	if (!(x & 0xffff0000u)) {
> +		x <<= 16;
> +		r -= 16;
> +	}
> +	if (!(x & 0xff000000u)) {
> +		x <<= 8;
> +		r -= 8;
> +	}
> +	if (!(x & 0xf0000000u)) {
> +		x <<= 4;
> +		r -= 4;
> +	}
> +	if (!(x & 0xc0000000u)) {
> +		x <<= 2;
> +		r -= 2;
> +	}
> +	if (!(x & 0x80000000u)) {
> +		x <<= 1;
> +		r -= 1;
> +	}
> +	return r;
> +}
> +
> +/*
> + * represent a polynomial over GF(2^m)
> + */
> +struct gf_poly {
> +	unsigned int deg;    /* polynomial degree */
> +	unsigned int c[0];   /* polynomial terms */
> +};
> +
> +/* given its degree, compute a polynomial size in bytes */
> +#define GF_POLY_SZ(_d) (sizeof(struct gf_poly)+((_d)+1)*sizeof(unsigned int))
> +
> +/* polynomial of degree 1 */
> +struct gf_poly_deg1 {
> +	struct gf_poly poly;
> +	unsigned int   c[2];
> +};
> +
> +/*
> + * same as encode_bch(), but process input data one byte at a time
> + */
> +static void encode_bch_unaligned(struct bch_control *bch,
> +				 const unsigned char *data, unsigned int len,
> +				 uint32_t *ecc)
> +{
> +	int i;
> +	const uint32_t *p;
> +	const int l = BCH_ECC_WORDS(bch)-1;
> +
> +	while (len--) {
> +		p = bch->mod8_tab + (l+1)*(((ecc[0] >> 24)^(*data++)) & 0xff);
> +
> +		for (i = 0; i < l; i++)
> +			ecc[i] = ((ecc[i] << 8)|(ecc[i+1] >> 24))^(*p++);
> +
> +		ecc[l] = (ecc[l] << 8)^(*p);
> +	}
> +}
> +
> +/*
> + * convert ecc bytes to aligned, zero-padded 32-bit ecc words
> + */
> +static void load_ecc8(struct bch_control *bch, uint32_t *dst,
> +		      const uint8_t *src)
> +{
> +	uint8_t pad[4] = {0, 0, 0, 0};
> +	unsigned int i, nwords = BCH_ECC_WORDS(bch)-1;
> +
> +	for (i = 0; i < nwords; i++, src += 4)
> +		dst[i] = (src[0] << 24)|(src[1] << 16)|(src[2] << 8)|src[3];
> +
> +	memcpy(pad, src, BCH_ECC_BYTES(bch)-4*nwords);
> +	dst[nwords] = (pad[0] << 24)|(pad[1] << 16)|(pad[2] << 8)|pad[3];
> +}
> +
> +/*
> + * convert 32-bit ecc words to ecc bytes
> + */
> +static void store_ecc8(struct bch_control *bch, uint8_t *dst,
> +		       const uint32_t *src)
> +{
> +	uint8_t pad[4];
> +	unsigned int i, nwords = BCH_ECC_WORDS(bch)-1;
> +
> +	for (i = 0; i < nwords; i++) {
> +		*dst++ = (src[i] >> 24);
> +		*dst++ = (src[i] >> 16) & 0xff;
> +		*dst++ = (src[i] >>  8) & 0xff;
> +		*dst++ = (src[i] >>  0) & 0xff;
> +	}
> +	pad[0] = (src[nwords] >> 24);
> +	pad[1] = (src[nwords] >> 16) & 0xff;
> +	pad[2] = (src[nwords] >>  8) & 0xff;
> +	pad[3] = (src[nwords] >>  0) & 0xff;
> +	memcpy(dst, pad, BCH_ECC_BYTES(bch)-4*nwords);
> +}
> +
> +/**
> + * encode_bch - calculate BCH ecc parity of data
> + * @bch:   BCH control structure
> + * @data:  data to encode
> + * @len:   data length in bytes
> + * @ecc:   ecc parity data, must be initialized by caller
> + *
> + * The @ecc parity array is used both as input and output parameter, in order to
> + * allow incremental computations. It should be of the size indicated by member
> + * @ecc_bytes of @bch, and should be initialized to 0 before the first call.
> + *
> + * The exact number of computed ecc parity bits is given by member @ecc_bits of
> + * @bch; it may be less than m*t for large values of t.
> + */
> +static void encode_bch(struct bch_control *bch, const uint8_t *data,
> +		unsigned int len, uint8_t *ecc)
> +{
> +	const unsigned int l = BCH_ECC_WORDS(bch)-1;
> +	unsigned int i, mlen;
> +	unsigned long m;
> +	uint32_t w, r[l+1];
> +	const uint32_t * const tab0 = bch->mod8_tab;
> +	const uint32_t * const tab1 = tab0 + 256*(l+1);
> +	const uint32_t * const tab2 = tab1 + 256*(l+1);
> +	const uint32_t * const tab3 = tab2 + 256*(l+1);
> +	const uint32_t *pdata, *p0, *p1, *p2, *p3;
> +
> +	if (ecc) {
> +		/* load ecc parity bytes into internal 32-bit buffer */
> +		load_ecc8(bch, bch->ecc_buf, ecc);
> +	} else {
> +		memset(bch->ecc_buf, 0, sizeof(r));
> +	}
> +
> +	/* process first unaligned data bytes */
> +	m = ((uintptr_t)data) & 3;
> +	if (m) {
> +		mlen = (len < (4-m)) ? len : 4-m;
> +		encode_bch_unaligned(bch, data, mlen, bch->ecc_buf);
> +		data += mlen;
> +		len  -= mlen;
> +	}
> +
> +	/* process 32-bit aligned data words */
> +	pdata = (uint32_t *)data;
> +	mlen  = len/4;
> +	data += 4*mlen;
> +	len  -= 4*mlen;
> +	memcpy(r, bch->ecc_buf, sizeof(r));
> +
> +	/*
> +	 * split each 32-bit word into 4 polynomials of weight 8 as follows:
> +	 *
> +	 * 31 ...24  23 ...16  15 ... 8  7 ... 0
> +	 * xxxxxxxx  yyyyyyyy  zzzzzzzz  tttttttt
> +	 *                               tttttttt  mod g = r0 (precomputed)
> +	 *                     zzzzzzzz  00000000  mod g = r1 (precomputed)
> +	 *           yyyyyyyy  00000000  00000000  mod g = r2 (precomputed)
> +	 * xxxxxxxx  00000000  00000000  00000000  mod g = r3 (precomputed)
> +	 * xxxxxxxx  yyyyyyyy  zzzzzzzz  tttttttt  mod g = r0^r1^r2^r3
> +	 */
> +	while (mlen--) {
> +		/* input data is read in big-endian format */
> +		w = r[0]^cpu_to_be32(*pdata++);
> +		p0 = tab0 + (l+1)*((w >>  0) & 0xff);
> +		p1 = tab1 + (l+1)*((w >>  8) & 0xff);
> +		p2 = tab2 + (l+1)*((w >> 16) & 0xff);
> +		p3 = tab3 + (l+1)*((w >> 24) & 0xff);
> +
> +		for (i = 0; i < l; i++)
> +			r[i] = r[i+1]^p0[i]^p1[i]^p2[i]^p3[i];
> +
> +		r[l] = p0[l]^p1[l]^p2[l]^p3[l];
> +	}
> +	memcpy(bch->ecc_buf, r, sizeof(r));
> +
> +	/* process last unaligned bytes */
> +	if (len)
> +		encode_bch_unaligned(bch, data, len, bch->ecc_buf);
> +
> +	/* store ecc parity bytes into original parity buffer */
> +	if (ecc)
> +		store_ecc8(bch, ecc, bch->ecc_buf);
> +}
> +
> +static inline int modulo(struct bch_control *bch, unsigned int v)
> +{
> +	const unsigned int n = GF_N(bch);
> +	while (v >= n) {
> +		v -= n;
> +		v = (v & n) + (v >> GF_M(bch));
> +	}
> +	return v;
> +}
> +
> +/*
> + * shorter and faster modulo function, only works when v < 2N.
> + */
> +static inline int mod_s(struct bch_control *bch, unsigned int v)
> +{
> +	const unsigned int n = GF_N(bch);
> +	return (v < n) ? v : v-n;
> +}
> +
> +static inline int deg(unsigned int poly)
> +{
> +	/* polynomial degree is the most-significant bit index */
> +	return fls(poly)-1;
> +}
> +
> +/* Galois field basic operations: multiply, divide, inverse, etc. */
> +
> +static inline unsigned int gf_mul(struct bch_control *bch, unsigned int a,
> +				  unsigned int b)
> +{
> +	return (a && b) ? bch->a_pow_tab[mod_s(bch, bch->a_log_tab[a]+
> +					       bch->a_log_tab[b])] : 0;
> +}
> +
> +static inline unsigned int gf_sqr(struct bch_control *bch, unsigned int a)
> +{
> +	return a ? bch->a_pow_tab[mod_s(bch, 2*bch->a_log_tab[a])] : 0;
> +}
> +
> +static inline unsigned int a_pow(struct bch_control *bch, int i)
> +{
> +	return bch->a_pow_tab[modulo(bch, i)];
> +}
> +
> +static inline int a_log(struct bch_control *bch, unsigned int x)
> +{
> +	return bch->a_log_tab[x];
> +}
> +
> +/*
> + * generate Galois field lookup tables
> + */
> +static int build_gf_tables(struct bch_control *bch, unsigned int poly)
> +{
> +	unsigned int i, x = 1;
> +	const unsigned int k = 1 << deg(poly);
> +
> +	/* primitive polynomial must be of degree m */
> +	if (k != (1u << GF_M(bch)))
> +		return -1;
> +
> +	for (i = 0; i < GF_N(bch); i++) {
> +		bch->a_pow_tab[i] = x;
> +		bch->a_log_tab[x] = i;
> +		if (i && (x == 1))
> +			/* polynomial is not primitive (a^i=1 with 0<i<2^m-1) */
> +			return -1;
> +		x <<= 1;
> +		if (x & k)
> +			x ^= poly;
> +	}
> +	bch->a_pow_tab[GF_N(bch)] = 1;
> +	bch->a_log_tab[0] = 0;
> +
> +	return 0;
> +}
> +
> +/*
> + * compute generator polynomial remainder tables for fast encoding
> + */
> +static void build_mod8_tables(struct bch_control *bch, const uint32_t *g)
> +{
> +	int i, j, b, d;
> +	uint32_t data, hi, lo, *tab;
> +	const int l = BCH_ECC_WORDS(bch);
> +	const int plen = DIV_ROUND_UP(bch->ecc_bits+1, 32);
> +	const int ecclen = DIV_ROUND_UP(bch->ecc_bits, 32);
> +
> +	memset(bch->mod8_tab, 0, 4*256*l*sizeof(*bch->mod8_tab));
> +
> +	for (i = 0; i < 256; i++) {
> +		/* p(X)=i is a small polynomial of weight <= 8 */
> +		for (b = 0; b < 4; b++) {
> +			/* we want to compute (p(X).X^(8*b+deg(g))) mod g(X) */
> +			tab = bch->mod8_tab + (b*256+i)*l;
> +			data = i << (8*b);
> +			while (data) {
> +				d = deg(data);
> +				/* subtract X^d.g(X) from p(X).X^(8*b+deg(g)) */
> +				data ^= g[0] >> (31-d);
> +				for (j = 0; j < ecclen; j++) {
> +					hi = (d < 31) ? g[j] << (d+1) : 0;
> +					lo = (j+1 < plen) ?
> +						g[j+1] >> (31-d) : 0;
> +					tab[j] ^= hi|lo;
> +				}
> +			}
> +		}
> +	}
> +}
> +
> +/*
> + * build a base for factoring degree 2 polynomials
> + */
> +static int build_deg2_base(struct bch_control *bch)
> +{
> +	const int m = GF_M(bch);
> +	int i, j, r;
> +	unsigned int sum, x, y, remaining, ak = 0, xi[m];
> +
> +	/* find k s.t. Tr(a^k) = 1 and 0 <= k < m */
> +	for (i = 0; i < m; i++) {
> +		for (j = 0, sum = 0; j < m; j++)
> +			sum ^= a_pow(bch, i*(1 << j));
> +
> +		if (sum) {
> +			ak = bch->a_pow_tab[i];
> +			break;
> +		}
> +	}
> +	/* find xi, i=0..m-1 such that xi^2+xi = a^i+Tr(a^i).a^k */
> +	remaining = m;
> +	memset(xi, 0, sizeof(xi));
> +
> +	for (x = 0; (x <= GF_N(bch)) && remaining; x++) {
> +		y = gf_sqr(bch, x)^x;
> +		for (i = 0; i < 2; i++) {
> +			r = a_log(bch, y);
> +			if (y && (r < m) && !xi[r]) {
> +				bch->xi_tab[r] = x;
> +				xi[r] = 1;
> +				remaining--;
> +				dbg("x%d = %x\n", r, x);
> +				break;
> +			}
> +			y ^= ak;
> +		}
> +	}
> +	/* should not happen but check anyway */
> +	return remaining ? -1 : 0;
> +}
> +
> +static void *bch_alloc(size_t size, int *err)
> +{
> +	void *ptr;
> +
> +	ptr = malloc(size);
> +	if (ptr == NULL)
> +		*err = 1;
> +	return ptr;
> +}
> +
> +/*
> + * compute generator polynomial for given (m,t) parameters.
> + */
> +static uint32_t *compute_generator_polynomial(struct bch_control *bch)
> +{
> +	const unsigned int m = GF_M(bch);
> +	const unsigned int t = GF_T(bch);
> +	int n, err = 0;
> +	unsigned int i, j, nbits, r, word, *roots;
> +	struct gf_poly *g;
> +	uint32_t *genpoly;
> +
> +	g = bch_alloc(GF_POLY_SZ(m*t), &err);
> +	roots = bch_alloc((bch->n+1)*sizeof(*roots), &err);
> +	genpoly = bch_alloc(DIV_ROUND_UP(m*t+1, 32)*sizeof(*genpoly), &err);
> +
> +	if (err) {
> +		kfree(genpoly);
> +		genpoly = NULL;
> +		goto finish;
> +	}
> +
> +	/* enumerate all roots of g(X) */
> +	memset(roots , 0, (bch->n+1)*sizeof(*roots));
> +	for (i = 0; i < t; i++) {
> +		for (j = 0, r = 2*i+1; j < m; j++) {
> +			roots[r] = 1;
> +			r = mod_s(bch, 2*r);
> +		}
> +	}
> +	/* build generator polynomial g(X) */
> +	g->deg = 0;
> +	g->c[0] = 1;
> +	for (i = 0; i < GF_N(bch); i++) {
> +		if (roots[i]) {
> +			/* multiply g(X) by (X+root) */
> +			r = bch->a_pow_tab[i];
> +			g->c[g->deg+1] = 1;
> +			for (j = g->deg; j > 0; j--)
> +				g->c[j] = gf_mul(bch, g->c[j], r)^g->c[j-1];
> +
> +			g->c[0] = gf_mul(bch, g->c[0], r);
> +			g->deg++;
> +		}
> +	}
> +	/* store left-justified binary representation of g(X) */
> +	n = g->deg+1;
> +	i = 0;
> +
> +	while (n > 0) {
> +		nbits = (n > 32) ? 32 : n;
> +		for (j = 0, word = 0; j < nbits; j++) {
> +			if (g->c[n-1-j])
> +				word |= 1u << (31-j);
> +		}
> +		genpoly[i++] = word;
> +		n -= nbits;
> +	}
> +	bch->ecc_bits = g->deg;
> +
> +finish:
> +	kfree(g);
> +	kfree(roots);
> +
> +	return genpoly;
> +}
> +
> +/**
> + *  free_bch - free the BCH control structure
> + *  @bch:    BCH control structure to release
> + */
> +static void free_bch(struct bch_control *bch)
> +{
> +	unsigned int i;
> +
> +	if (bch) {
> +		kfree(bch->a_pow_tab);
> +		kfree(bch->a_log_tab);
> +		kfree(bch->mod8_tab);
> +		kfree(bch->ecc_buf);
> +		kfree(bch->ecc_buf2);
> +		kfree(bch->xi_tab);
> +		kfree(bch->syn);
> +		kfree(bch->cache);
> +		kfree(bch->elp);
> +
> +		for (i = 0; i < ARRAY_SIZE(bch->poly_2t); i++)
> +			kfree(bch->poly_2t[i]);
> +
> +		kfree(bch);
> +	}
> +}
> +
> +/**
> + * init_bch - initialize a BCH encoder/decoder
> + * @m:          Galois field order, should be in the range 5-15
> + * @t:          maximum error correction capability, in bits
> + * @prim_poly:  user-provided primitive polynomial (or 0 to use default)
> + *
> + * Returns:
> + *  a newly allocated BCH control structure if successful, NULL otherwise
> + *
> + * This initialization can take some time, as lookup tables are built for fast
> + * encoding/decoding; make sure not to call this function from a time critical
> + * path. Usually, init_bch() should be called on module/driver init and
> + * free_bch() should be called to release memory on exit.
> + *
> + * You may provide your own primitive polynomial of degree @m in argument
> + * @prim_poly, or let init_bch() use its default polynomial.
> + *
> + * Once init_bch() has successfully returned a pointer to a newly allocated
> + * BCH control structure, ecc length in bytes is given by member @ecc_bytes of
> + * the structure.
> + */
> +static struct bch_control *init_bch(int m, int t, unsigned int prim_poly)
> +{
> +	int err = 0;
> +	unsigned int i, words;
> +	uint32_t *genpoly;
> +	struct bch_control *bch = NULL;
> +
> +	const int min_m = 5;
> +	const int max_m = 15;
> +
> +	/* default primitive polynomials */
> +	static const unsigned int prim_poly_tab[] = {
> +		0x25, 0x43, 0x83, 0x11d, 0x211, 0x409, 0x805, 0x1053, 0x201b,
> +		0x402b, 0x8003,
> +	};
> +
> +#if defined(CONFIG_BCH_CONST_PARAMS)
> +	if ((m != (CONFIG_BCH_CONST_M)) || (t != (CONFIG_BCH_CONST_T))) {
> +		printk(KERN_ERR "bch encoder/decoder was configured to support "
> +		       "parameters m=%d, t=%d only!\n",
> +		       CONFIG_BCH_CONST_M, CONFIG_BCH_CONST_T);
> +		goto fail;
> +	}
> +#endif
> +	if ((m < min_m) || (m > max_m))
> +		/*
> +		 * values of m greater than 15 are not currently supported;
> +		 * supporting m > 15 would require changing table base type
> +		 * (uint16_t) and a small patch in matrix transposition
> +		 */
> +		goto fail;
> +
> +	/* sanity checks */
> +	if ((t < 1) || (m*t >= ((1 << m)-1)))
> +		/* invalid t value */
> +		goto fail;
> +
> +	/* select a primitive polynomial for generating GF(2^m) */
> +	if (prim_poly == 0)
> +		prim_poly = prim_poly_tab[m-min_m];
> +
> +	bch = malloc(sizeof(*bch));
> +	if (bch == NULL)
> +		goto fail;
> +
> +	memset(bch, 0, sizeof(*bch));
> +
> +	bch->m = m;
> +	bch->t = t;
> +	bch->n = (1 << m)-1;
> +	words  = DIV_ROUND_UP(m*t, 32);
> +	bch->ecc_bytes = DIV_ROUND_UP(m*t, 8);
> +	bch->a_pow_tab = bch_alloc((1+bch->n)*sizeof(*bch->a_pow_tab), &err);
> +	bch->a_log_tab = bch_alloc((1+bch->n)*sizeof(*bch->a_log_tab), &err);
> +	bch->mod8_tab  = bch_alloc(words*1024*sizeof(*bch->mod8_tab), &err);
> +	bch->ecc_buf   = bch_alloc(words*sizeof(*bch->ecc_buf), &err);
> +	bch->ecc_buf2  = bch_alloc(words*sizeof(*bch->ecc_buf2), &err);
> +	bch->xi_tab    = bch_alloc(m*sizeof(*bch->xi_tab), &err);
> +	bch->syn       = bch_alloc(2*t*sizeof(*bch->syn), &err);
> +	bch->cache     = bch_alloc(2*t*sizeof(*bch->cache), &err);
> +	bch->elp       = bch_alloc((t+1)*sizeof(struct gf_poly_deg1), &err);
> +
> +	for (i = 0; i < ARRAY_SIZE(bch->poly_2t); i++)
> +		bch->poly_2t[i] = bch_alloc(GF_POLY_SZ(2*t), &err);
> +
> +	if (err)
> +		goto fail;
> +
> +	err = build_gf_tables(bch, prim_poly);
> +	if (err)
> +		goto fail;
> +
> +	/* use generator polynomial for computing encoding tables */
> +	genpoly = compute_generator_polynomial(bch);
> +	if (genpoly == NULL)
> +		goto fail;
> +
> +	build_mod8_tables(bch, genpoly);
> +	kfree(genpoly);
> +
> +	err = build_deg2_base(bch);
> +	if (err)
> +		goto fail;
> +
> +	return bch;
> +
> +fail:
> +	free_bch(bch);
> +	return NULL;
> +}
> +
> +static void swap_bits(uint8_t *buf, int len)
> +{
> +	int i, j;
> +
> +	for (j = 0; j < len; j++) {
> +		uint8_t byte = buf[j];
> +
> +		buf[j] = 0;
> +		for (i = 0; i < 8; i++) {
> +			if (byte & (1 << i))
> +				buf[j] |= (1 << (7 - i));
> +		}
> +	}
> +}
> +
> +static uint16_t lfsr_step(uint16_t state, int count)
> +{
> +	state &= 0x7fff;
> +	while (count--)
> +		state = ((state >> 1) |
> +			 ((((state >> 0) ^ (state >> 1)) & 1) << 14)) & 0x7fff;
> +
> +	return state;
> +}
> +
> +static uint16_t default_scrambler_seeds[] = {
> +	0x2b75, 0x0bd0, 0x5ca3, 0x62d1, 0x1c93, 0x07e9, 0x2162, 0x3a72,
> +	0x0d67, 0x67f9, 0x1be7, 0x077d, 0x032f, 0x0dac, 0x2716, 0x2436,
> +	0x7922, 0x1510, 0x3860, 0x5287, 0x480f, 0x4252, 0x1789, 0x5a2d,
> +	0x2a49, 0x5e10, 0x437f, 0x4b4e, 0x2f45, 0x216e, 0x5cb7, 0x7130,
> +	0x2a3f, 0x60e4, 0x4dc9, 0x0ef0, 0x0f52, 0x1bb9, 0x6211, 0x7a56,
> +	0x226d, 0x4ea7, 0x6f36, 0x3692, 0x38bf, 0x0c62, 0x05eb, 0x4c55,
> +	0x60f4, 0x728c, 0x3b6f, 0x2037, 0x7f69, 0x0936, 0x651a, 0x4ceb,
> +	0x6218, 0x79f3, 0x383f, 0x18d9, 0x4f05, 0x5c82, 0x2912, 0x6f17,
> +	0x6856, 0x5938, 0x1007, 0x61ab, 0x3e7f, 0x57c2, 0x542f, 0x4f62,
> +	0x7454, 0x2eac, 0x7739, 0x42d4, 0x2f90, 0x435a, 0x2e52, 0x2064,
> +	0x637c, 0x66ad, 0x2c90, 0x0bad, 0x759c, 0x0029, 0x0986, 0x7126,
> +	0x1ca7, 0x1605, 0x386a, 0x27f5, 0x1380, 0x6d75, 0x24c3, 0x0f8e,
> +	0x2b7a, 0x1418, 0x1fd1, 0x7dc1, 0x2d8e, 0x43af, 0x2267, 0x7da3,
> +	0x4e3d, 0x1338, 0x50db, 0x454d, 0x764d, 0x40a3, 0x42e6, 0x262b,
> +	0x2d2e, 0x1aea, 0x2e17, 0x173d, 0x3a6e, 0x71bf, 0x25f9, 0x0a5d,
> +	0x7c57, 0x0fbe, 0x46ce, 0x4939, 0x6b17, 0x37bb, 0x3e91, 0x76db,
> +};
> +
> +static uint16_t brom_scrambler_seeds[] = { 0x4a80 };
> +
> +static void scramble(const struct image_info *info,
> +		     int page, uint8_t *data, int datalen)
> +{
> +	uint16_t state;
> +	int i;
> +
> +	/* Boot0 is always scrambled no matter the command line option. */
> +	if (info->boot0) {
> +		state = brom_scrambler_seeds[0];
> +	} else {
> +		unsigned seedmod = info->eraseblock_size / info->page_size;
> +
> +		/* Bail out earlier if the user didn't ask for scrambling. */
> +		if (!info->scramble)
> +			return;
> +
> +		if (seedmod > ARRAY_SIZE(default_scrambler_seeds))
> +			seedmod = ARRAY_SIZE(default_scrambler_seeds);
> +
> +		state = default_scrambler_seeds[page % seedmod];
> +	}
> +
> +	/* Prepare the initial state... */
> +	state = lfsr_step(state, 15);
> +
> +	/* and start scrambling data. */
> +	for (i = 0; i < datalen; i++) {
> +		data[i] ^= state;
> +		state = lfsr_step(state, 8);
> +	}
> +}
> +
> +static int write_page(const struct image_info *info, uint8_t *buffer,
> +		      FILE *src, FILE *rnd, FILE *dst,
> +		      struct bch_control *bch, int page)
> +{
> +	int steps = info->usable_page_size / info->ecc_step_size;
> +	int eccbytes = DIV_ROUND_UP(info->ecc_strength * 14, 8);
> +	off_t pos = ftell(dst);
> +	size_t pad, cnt;
> +	int i;
> +
> +	if (eccbytes % 2)
> +		eccbytes++;
> +
> +	memset(buffer, 0xff, info->page_size + info->oob_size);
> +	cnt = fread(buffer, 1, info->usable_page_size, src);
> +	if (!cnt) {
> +		if (!feof(src)) {
> +			fprintf(stderr,
> +				"Failed to read data from the source\n");
> +			return -1;
> +		} else {
> +			return 0;
> +		}
> +	}
> +
> +	fwrite(buffer, info->page_size + info->oob_size, 1, dst);
> +
> +	for (i = 0; i < info->usable_page_size; i++) {
> +		if (buffer[i] !=  0xff)
> +			break;
> +	}
> +
> +	/* We leave empty pages at 0xff. */
> +	if (i == info->usable_page_size)
> +		return 0;
> +
> +	/* Restore the source pointer to read it again. */
> +	fseek(src, -cnt, SEEK_CUR);
> +
> +	/* Randomize unused space if scrambling is required. */
> +	if (info->scramble) {
> +		int offs;
> +
> +		if (info->boot0) {
> +			offs = steps * (info->ecc_step_size + eccbytes + 4);
> +			cnt = info->page_size + info->oob_size - offs;
> +			fread(buffer + offs, 1, cnt, rnd);
> +		} else {
> +			offs = info->page_size + (steps * (eccbytes + 4));
> +			cnt = info->page_size + info->oob_size - offs;
> +			memset(buffer + offs, 0xff, cnt);
> +			scramble(info, page, buffer + offs, cnt);
> +		}
> +		fseek(dst, pos + offs, SEEK_SET);
> +		fwrite(buffer + offs, cnt, 1, dst);
> +	}
> +
> +	for (i = 0; i < steps; i++) {
> +		int ecc_offs, data_offs;
> +		uint8_t *ecc;
> +
> +		memset(buffer, 0xff, info->ecc_step_size + eccbytes + 4);
> +		ecc = buffer + info->ecc_step_size + 4;
> +		if (info->boot0) {
> +			data_offs = i * (info->ecc_step_size + eccbytes + 4);
> +			ecc_offs = data_offs + info->ecc_step_size + 4;
> +		} else {
> +			data_offs = i * info->ecc_step_size;
> +			ecc_offs = info->page_size + 4 + (i * (eccbytes + 4));
> +		}
> +
> +		cnt = fread(buffer, 1, info->ecc_step_size, src);
> +		if (!cnt && !feof(src)) {
> +			fprintf(stderr,
> +				"Failed to read data from the source\n");
> +			return -1;
> +		}
> +
> +		pad = info->ecc_step_size - cnt;
> +		if (pad) {
> +			if (info->scramble && info->boot0)
> +				fread(buffer + cnt, 1, pad, rnd);
> +			else
> +				memset(buffer + cnt, 0xff, pad);
> +		}
> +
> +		memset(ecc, 0, eccbytes);
> +		swap_bits(buffer, info->ecc_step_size + 4);
> +		encode_bch(bch, buffer, info->ecc_step_size + 4, ecc);
> +		swap_bits(buffer, info->ecc_step_size + 4);
> +		swap_bits(ecc, eccbytes);
> +		scramble(info, page, buffer, info->ecc_step_size + 4 + eccbytes);
> +
> +		fseek(dst, pos + data_offs, SEEK_SET);
> +		fwrite(buffer, info->ecc_step_size, 1, dst);
> +		fseek(dst, pos + ecc_offs - 4, SEEK_SET);
> +		fwrite(ecc - 4, eccbytes + 4, 1, dst);
> +	}
> +
> +	/* Fix BBM. */
> +	fseek(dst, pos + info->page_size, SEEK_SET);
> +	memset(buffer, 0xff, 2);
> +	fwrite(buffer, 2, 1, dst);
> +
> +	/* Make dst pointer point to the next page. */
> +	fseek(dst, pos + info->page_size + info->oob_size, SEEK_SET);
> +
> +	return 0;
> +}
> +
> +static int create_image(const struct image_info *info)
> +{
> +	off_t page = info->offset / info->page_size;
> +	struct bch_control *bch;
> +	FILE *src, *dst, *rnd;
> +	uint8_t *buffer;
> +
> +	bch = init_bch(14, info->ecc_strength, BCH_PRIMITIVE_POLY);
> +	if (!bch) {
> +		fprintf(stderr, "Failed to init the BCH engine\n");
> +		return -1;
> +	}
> +
> +	buffer = malloc(info->page_size + info->oob_size);
> +	if (!buffer) {
> +		fprintf(stderr, "Failed to allocate the NAND page buffer\n");
> +		return -1;
> +	}
> +
> +	memset(buffer, 0xff, info->page_size + info->oob_size);
> +
> +	src = fopen(info->source, "r");
> +	if (!src) {
> +		fprintf(stderr, "Failed to open source file (%s)\n",
> +			info->source);
> +		return -1;
> +	}
> +
> +	dst = fopen(info->dest, "w");
> +	if (!dst) {
> +		fprintf(stderr, "Failed to open dest file (%s)\n", info->dest);
> +		return -1;
> +	}
> +
> +	rnd = fopen("/dev/urandom", "r");
> +	if (!rnd) {
> +		fprintf(stderr, "Failed to open /dev/urandom\n");
> +		return -1;
> +	}
> +
> +	while (!feof(src)) {
> +		int ret;
> +
> +		ret = write_page(info, buffer, src, rnd, dst, bch, page++);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static void display_help(int status)
> +{
> +	fprintf(status == EXIT_SUCCESS ? stdout : stderr,
> +		"sunxi-nand-image-builder %s\n"
> +		"\n"
> +		"Usage: sunxi-nand-image-builder [OPTIONS] source-image output-image\n"
> +		"\n"
> +		"Creates a raw NAND image that can be read by the sunxi NAND controller.\n"
> +		"\n"
> +		"-h               --help               Display this help and exit\n"
> +		"-c <str>/<step>  --ecc=<str>/<step>   ECC config (strength/step-size)\n"
> +		"-p <size>        --page=<size>        Page size\n"
> +		"-o <size>        --oob=<size>         OOB size\n"
> +		"-u <size>        --usable=<size>      Usable page size\n"
> +		"-e <size>        --eraseblock=<size>  Erase block size\n"
> +		"-b               --boot0              Build a boot0 image.\n"
> +		"-s               --scramble           Scramble data\n"
> +		"-a <offset>      --address=<offset>   Where the image will be programmed.\n"
> +		"\n"
> +		"Notes:\n"
> +		"All the information you need to pass to this tool should be part of\n"
> +		"the NAND datasheet.\n"
> +		"\n"
> +		"The NAND controller only supports the following ECC configs\n"
> +		"  Valid ECC strengths: 16, 24, 28, 32, 40, 48, 56, 60 and 64\n"
> +		"  Valid ECC step size: 512 and 1024\n"
> +		"\n"
> +		"If you are building a boot0 image, you'll have specify extra options.\n"
> +		"These options should be chosen based on the layouts described here:\n"
> +		"  http://linux-sunxi.org/NAND#More_information_on_BROM_NAND\n"
> +		"\n"
> +		"  --usable should be assigned the 'Hardware page' value\n"
> +		"  --ecc should be assigned the 'ECC capacity'/'ECC page' values\n"
> +		"  --usable should be smaller than --page\n"
> +		"\n"
> +		"The --address option is only required for non-boot0 images that are \n"
> +		"meant to be programmed at a non eraseblock aligned offset.\n"
> +		"\n"
> +		"Examples:\n"
> +		"  The H27UCG8T2BTR-BC NAND exposes\n"
> +		"  * 16k pages\n"
> +		"  * 1280 OOB bytes per page\n"
> +		"  * 4M eraseblocks\n"
> +		"  * requires data scrambling\n"
> +		"  * expects a minimum ECC of 40bits/1024bytes\n"
> +		"\n"
> +		"  A normal image can be generated with\n"
> +		"    sunxi-nand-image-builder -p 16384 -o 1280 -e 0x400000 -s -c 40/1024\n"
> +		"  A boot0 image can be generated with\n"
> +		"    sunxi-nand-image-builder -p 16384 -o 1280 -e 0x400000 -s -b -u 4096 -c 64/1024\n",
> +		PLAIN_VERSION);
> +	exit(status);
> +}
> +
> +static int check_image_info(struct image_info *info)
> +{
> +	static int valid_ecc_strengths[] = { 16, 24, 28, 32, 40, 48, 56, 60, 64 };
> +	int eccbytes, eccsteps;
> +	unsigned i;
> +
> +	if (!info->page_size) {
> +		fprintf(stderr, "--page is missing\n");
> +		return -EINVAL;
> +	}
> +
> +	if (!info->page_size) {
> +		fprintf(stderr, "--oob is missing\n");
> +		return -EINVAL;
> +	}
> +
> +	if (!info->eraseblock_size) {
> +		fprintf(stderr, "--eraseblock is missing\n");
> +		return -EINVAL;
> +	}
> +
> +	if (info->ecc_step_size != 512 && info->ecc_step_size != 1024) {
> +		fprintf(stderr, "Invalid ECC step argument: %d\n",
> +			info->ecc_step_size);
> +		return -EINVAL;
> +	}
> +
> +	for (i = 0; i < ARRAY_SIZE(valid_ecc_strengths); i++) {
> +		if (valid_ecc_strengths[i] == info->ecc_strength)
> +			break;
> +	}
> +
> +	if (i == ARRAY_SIZE(valid_ecc_strengths)) {
> +		fprintf(stderr, "Invalid ECC strength argument: %d\n",
> +			info->ecc_strength);
> +		return -EINVAL;
> +	}
> +
> +	eccbytes = DIV_ROUND_UP(info->ecc_strength * 14, 8);
> +	if (eccbytes % 2)
> +		eccbytes++;
> +	eccbytes += 4;
> +
> +	eccsteps = info->usable_page_size / info->ecc_step_size;
> +
> +	if (info->page_size + info->oob_size <
> +	    info->usable_page_size + (eccsteps * eccbytes)) {
> +		fprintf(stderr,
> +			"ECC bytes do not fit in the NAND page, choose a weaker ECC\n");
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +int main(int argc, char **argv)
> +{
> +	struct image_info info;
> +
> +	memset(&info, 0, sizeof(info));
> +	/*
> +	 * Process user arguments
> +	 */
> +	for (;;) {
> +		int option_index = 0;
> +		char *endptr = NULL;
> +		static const struct option long_options[] = {
> +			{"help", no_argument, 0, 'h'},
> +			{"ecc", required_argument, 0, 'c'},
> +			{"page", required_argument, 0, 'p'},
> +			{"oob", required_argument, 0, 'o'},
> +			{"usable", required_argument, 0, 'u'},
> +			{"eraseblock", required_argument, 0, 'e'},
> +			{"boot0", no_argument, 0, 'b'},
> +			{"scramble", no_argument, 0, 's'},
> +			{"address", required_argument, 0, 'a'},
> +			{0, 0, 0, 0},
> +		};
> +
> +		int c = getopt_long(argc, argv, "c:p:o:u:e:ba:sh",
> +				long_options, &option_index);
> +		if (c == EOF)
> +			break;
> +
> +		switch (c) {
> +		case 'h':
> +			display_help(0);
> +			break;
> +		case 's':
> +			info.scramble = 1;
> +			break;
> +		case 'c':
> +			info.ecc_strength = strtol(optarg, &endptr, 0);
> +			if (endptr || *endptr == '/')
> +				info.ecc_step_size = strtol(endptr + 1, NULL, 0);
> +			break;
> +		case 'p':
> +			info.page_size = strtol(optarg, NULL, 0);
> +			break;
> +		case 'o':
> +			info.oob_size = strtol(optarg, NULL, 0);
> +			break;
> +		case 'u':
> +			info.usable_page_size = strtol(optarg, NULL, 0);
> +			break;
> +		case 'e':
> +			info.eraseblock_size = strtol(optarg, NULL, 0);
> +			break;
> +		case 'b':
> +			info.boot0 = 1;
> +			break;
> +		case 'a':
> +			info.offset = strtoull(optarg, NULL, 0);
> +			break;
> +		case '?':
> +			display_help(-1);
> +			break;
> +		}
> +	}
> +
> +	if ((argc - optind) != 2)
> +		display_help(-1);
> +
> +	info.source = argv[optind];
> +	info.dest = argv[optind + 1];
> +
> +	if (!info.boot0) {
> +		info.usable_page_size = info.page_size;
> +	} else if (!info.usable_page_size) {
> +		if (info.page_size > 8192)
> +			info.usable_page_size = 8192;
> +		else if (info.page_size > 4096)
> +			info.usable_page_size = 4096;
> +		else
> +			info.usable_page_size = 1024;
> +	}
> +
> +	if (check_image_info(&info))
> +		display_help(-1);
> +
> +	return create_image(&info);
> +}