Re: [PATCH 3/3] mtd: nand: sunxi: add randomizer support

[Richard Weinberger]

On Thu, Oct 15, 2015 at 7:17 PM, Boris Brezillon
<boris.brezillon@xxxxxxxxxxxxxxxxxx> wrote:
> +static const u16 sunxi_nfc_randomizer_page_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 const u16 sunxi_nfc_randomizer_ecc512_seeds[] = {
> +       0x227b, 0x5baa, 0x15ef, 0x5b13, 0x75b8, 0x04f7, 0x4b5e, 0x4db8,
> +       0x4f31, 0x669a, 0x20af, 0x5b91, 0x1d6d, 0x286a, 0x5e98, 0x07f1,
> +       0x44b2, 0x0288, 0x3996, 0x7a98, 0x76cc, 0x705a, 0x21c9, 0x5be5,
> +       0x23b8, 0x7133, 0x5514, 0x6f0b, 0x7528, 0x5e5b, 0x2ae1, 0x37b6,
> +       0x0d19, 0x1525, 0x2f87, 0x0025, 0x0107, 0x7012, 0x0b4f, 0x12e1,
> +       0x4e29, 0x6a5e, 0x744a, 0x0032, 0x61c3, 0x1463, 0x3cd4, 0x5636,
> +       0x5928, 0x57bf, 0x3ce1, 0x6c35, 0x4167, 0x58cc, 0x7e7f, 0x4ecd,
> +       0x05c9, 0x3063, 0x01ab, 0x194f, 0x6b7c, 0x6575, 0x29f5, 0x04d0,
> +       0x1e53, 0x4d18, 0x2f12, 0x21c4, 0x3379, 0x12ba, 0x660a, 0x6150,
> +       0x2f0e, 0x7339, 0x3bd6, 0x5ab0, 0x72fa, 0x568d, 0x5bf6, 0x410d,
> +       0x1e35, 0x2971, 0x3389, 0x420c, 0x5985, 0x169c, 0x6cb3, 0x3139,
> +       0x52ac, 0x1475, 0x6611, 0x47df, 0x2c0b, 0x14dd, 0x1839, 0x0853,
> +       0x667f, 0x245f, 0x3d7e, 0x5eb1, 0x13d1, 0x4945, 0x11ae, 0x4f1e,
> +       0x19bc, 0x7e72, 0x1206, 0x3a64, 0x6c27, 0x1d33, 0x3726, 0x37db,
> +       0x6ba3, 0x1dfb, 0x7041, 0x66b5, 0x14b0, 0x13da, 0x5378, 0x0696,
> +       0x7887, 0x5c44, 0x4a7e, 0x2888, 0x0794, 0x567f, 0x57bb, 0x0ac0,
> +};
> +
> +static const u16 sunxi_nfc_randomizer_ecc1024_seeds[] = {
> +       0x48a6, 0x595e, 0x42c7, 0x63a7, 0x329c, 0x250d, 0x2306, 0x2324,
> +       0x4c68, 0x5f64, 0x2656, 0x3a4e, 0x1da6, 0x6b01, 0x775d, 0x2efc,
> +       0x3afa, 0x07cc, 0x378e, 0x6e39, 0x64cf, 0x00ce, 0x042b, 0x2d6e,
> +       0x092a, 0x66b7, 0x45cb, 0x5dd8, 0x1ef9, 0x7600, 0x3dcc, 0x2bfa,
> +       0x0796, 0x4d1c, 0x1cf5, 0x0399, 0x62d3, 0x56fc, 0x33cb, 0x2c74,
> +       0x26b2, 0x79f7, 0x4f87, 0x6d96, 0x6fec, 0x777b, 0x7dae, 0x2523,
> +       0x0115, 0x0b1c, 0x323a, 0x6438, 0x7ebd, 0x7a81, 0x0739, 0x1df7,
> +       0x1d4f, 0x6e1f, 0x0fa4, 0x3f79, 0x18bd, 0x1255, 0x43b1, 0x1f15,
> +       0x2446, 0x5b56, 0x2b13, 0x79ae, 0x3ce6, 0x674a, 0x7301, 0x1288,
> +       0x721b, 0x3892, 0x0618, 0x0a05, 0x791e, 0x265b, 0x3062, 0x0914,
> +       0x46ea, 0x50da, 0x38ad, 0x20e7, 0x04e2, 0x3696, 0x4ed2, 0x0d70,
> +       0x5585, 0x71f4, 0x080b, 0x2e22, 0x28eb, 0x6f80, 0x5109, 0x2bb0,
> +       0x0ca1, 0x2159, 0x1a8a, 0x61c1, 0x38b2, 0x59ae, 0x1937, 0x1076,
> +       0x6a33, 0x7abc, 0x4630, 0x4b37, 0x11b4, 0x4d1b, 0x079f, 0x7e51,
> +       0x40e8, 0x7b41, 0x7bc4, 0x037a, 0x3a2b, 0x0fb5, 0x7a06, 0x6401,
> +       0x6792, 0x7fab, 0x7bcd, 0x1ac6, 0x1d51, 0x1b91, 0x781f, 0x5776,
> +};

Can you please outline which constants and functions are taken as-is from
the Allwinner BSP?

> +static u16 sunxi_nfc_randomizer_step(u16 state, int count)
> +{
> +       state &= 0x7fff;
> +       while (count--)
> +               state = ((state >> 1) |
> +                        ((((state >> 0) ^ (state >> 1)) & 1) << 14)) & 0x7fff;

As discussed on IRC, state >> 0 is state again.

> +
> +       return state;
> +}
> +
> +static u16 sunxi_nfc_randomizer_state(struct mtd_info *mtd, int page, bool ecc)
> +{
> +       const u16 *seeds = sunxi_nfc_randomizer_page_seeds;
> +       int mod = mtd->erasesize / mtd->writesize;

IIRC mtd.h has a helper for such divisions.

> +       sunxi_nfc_randomizer_enable(mtd);
>         writel(NFC_DATA_TRANS | NFC_DATA_SWAP_METHOD | NFC_ECC_OP,
>                nfc->regs + NFC_REG_CMD);
> +       sunxi_nfc_randomizer_disable(mtd);
>
>         ret = sunxi_nfc_wait_int(nfc, NFC_CMD_INT_FLAG, 0);
>         if (ret)
>                 return ret;
>
> +       *cur_off = oob_off + ecc->bytes + 4;

Hmmm, why do we need this here?
At the end of this function you do it again.

-- 
Thanks,
//richard
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