From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8A0F6C433E0 for ; Tue, 19 May 2020 08:41:29 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 51A5E204EA for ; Tue, 19 May 2020 08:41:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="MKuGY/1D" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 51A5E204EA Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=collabora.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=KgIb3YW+/XBNh+zwNvpBNd8vdQqt9rQXhA2NCMAVppE=; b=MKuGY/1DwSliiy 21VKKqYP3S8+VOLwY2LzrGGaSshEojA5UO0dnK2xIZ1hPwl3GvWYtWNGL3cqrm2V/QQW21mAqvV+a /QoF5Z3bdLziHzx0WtGF2Sx0xpy9tm3RcsFzm+C5VzdkWIKgIBOVC6QTKry2GoFXJDV6LwYzxPkeJ k9ZP8nw3C7UkTOJ7oYlWrfSUNHpOJQlaIYneq1dFvJijCTjT/aeO+PlZWMHpIMtb4kmEdMk2HilqP eLloc1pv5AL4iNjQq12BJtdpprghOC6vtxsQLZcNOcpnAELBEY6jwBHhJgtrzR+oAOnmviLn3a5AQ 9iie6UuSYyxi3z4/O6dw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jaxoP-0004pW-13; Tue, 19 May 2020 08:41:21 +0000 Received: from bhuna.collabora.co.uk ([2a00:1098:0:82:1000:25:2eeb:e3e3]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jaxoL-0004oF-R8 for linux-mtd@lists.infradead.org; Tue, 19 May 2020 08:41:20 +0000 Received: from localhost (unknown [IPv6:2a01:e0a:2c:6930:5cf4:84a1:2763:fe0d]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: bbrezillon) by bhuna.collabora.co.uk (Postfix) with ESMTPSA id 33DB02A06EC; Tue, 19 May 2020 09:41:16 +0100 (BST) Date: Tue, 19 May 2020 10:41:07 +0200 From: Boris Brezillon To: Miquel Raynal Subject: Re: [PATCH v5 2/8] lib/bch: Allow easy bit swapping Message-ID: <20200519104107.70f93419@collabora.com> In-Reply-To: <20200519074549.23673-3-miquel.raynal@bootlin.com> References: <20200519074549.23673-1-miquel.raynal@bootlin.com> <20200519074549.23673-3-miquel.raynal@bootlin.com> Organization: Collabora X-Mailer: Claws Mail 3.17.5 (GTK+ 2.24.32; x86_64-redhat-linux-gnu) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200519_014118_161870_38CFE1C2 X-CRM114-Status: GOOD ( 29.42 ) X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Michal Simek , Vignesh Raghavendra , Tudor Ambarus , Richard Weinberger , linux-mtd@lists.infradead.org, Thomas Petazzoni , Naga Sureshkumar Relli Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-mtd" Errors-To: linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org On Tue, 19 May 2020 09:45:43 +0200 Miquel Raynal wrote: > It seems that several hardware ECC engine use a swapped representation > of bytes compared to software. This might having to do with how the > ECC engine is wired to the NAND controller or the order the bits are > passed to the hardware BCH logic. > > This means that when the software BCH engine is working in conjunction > with data generated with hardware, sometimes we might need to swap the > bits inside bytes, eg: > > 0x0A = b0000_1010 -> b0101_0000 = 0x50 > > Make it possible by adding a boolean to the BCH initialization routine. > > Regarding the implementation itself, this is a rather simple approach > that can probably be enhanced in the future by preparing the > ->a_{mod,pow}_tab tables with the swapping in mind. > > Suggested-by: Boris Brezillon > Signed-off-by: Miquel Raynal Reviewed-by: Boris Brezillon > --- > drivers/mtd/devices/docg3.c | 2 +- > drivers/mtd/nand/raw/nand_bch.c | 2 +- > include/linux/bch.h | 5 +- > lib/bch.c | 90 ++++++++++++++++++++++++++++----- > 4 files changed, 82 insertions(+), 17 deletions(-) > > diff --git a/drivers/mtd/devices/docg3.c b/drivers/mtd/devices/docg3.c > index 799df8d03357..a030792115bc 100644 > --- a/drivers/mtd/devices/docg3.c > +++ b/drivers/mtd/devices/docg3.c > @@ -1985,7 +1985,7 @@ static int __init docg3_probe(struct platform_device *pdev) > cascade->base = base; > mutex_init(&cascade->lock); > cascade->bch = bch_init(DOC_ECC_BCH_M, DOC_ECC_BCH_T, > - DOC_ECC_BCH_PRIMPOLY); > + DOC_ECC_BCH_PRIMPOLY, false); > if (!cascade->bch) > return ret; > > diff --git a/drivers/mtd/nand/raw/nand_bch.c b/drivers/mtd/nand/raw/nand_bch.c > index d95fcc7358e9..d5af8c5fd02f 100644 > --- a/drivers/mtd/nand/raw/nand_bch.c > +++ b/drivers/mtd/nand/raw/nand_bch.c > @@ -130,7 +130,7 @@ struct nand_bch_control *nand_bch_init(struct mtd_info *mtd) > if (!nbc) > goto fail; > > - nbc->bch = bch_init(m, t, 0); > + nbc->bch = bch_init(m, t, 0, false); > if (!nbc->bch) > goto fail; > > diff --git a/include/linux/bch.h b/include/linux/bch.h > index 9c35e7cd5890..85fdce83d4e2 100644 > --- a/include/linux/bch.h > +++ b/include/linux/bch.h > @@ -33,6 +33,7 @@ > * @cache: log-based polynomial representation buffer > * @elp: error locator polynomial > * @poly_2t: temporary polynomials of degree 2t > + * @swap_bits: swap bits within data and syndrome bytes > */ > struct bch_control { > unsigned int m; > @@ -51,9 +52,11 @@ struct bch_control { > int *cache; > struct gf_poly *elp; > struct gf_poly *poly_2t[4]; > + bool swap_bits; > }; > > -struct bch_control *bch_init(int m, int t, unsigned int prim_poly); > +struct bch_control *bch_init(int m, int t, unsigned int prim_poly, > + bool swap_bits); > > void bch_free(struct bch_control *bch); > > diff --git a/lib/bch.c b/lib/bch.c > index 1091841ac716..7c031ee8b93b 100644 > --- a/lib/bch.c > +++ b/lib/bch.c > @@ -114,6 +114,49 @@ struct gf_poly_deg1 { > unsigned int c[2]; > }; > > +static u8 swap_bits_table[] = { > + 0x00, 0x80, 0x40, 0xc0, 0x20, 0xa0, 0x60, 0xe0, > + 0x10, 0x90, 0x50, 0xd0, 0x30, 0xb0, 0x70, 0xf0, > + 0x08, 0x88, 0x48, 0xc8, 0x28, 0xa8, 0x68, 0xe8, > + 0x18, 0x98, 0x58, 0xd8, 0x38, 0xb8, 0x78, 0xf8, > + 0x04, 0x84, 0x44, 0xc4, 0x24, 0xa4, 0x64, 0xe4, > + 0x14, 0x94, 0x54, 0xd4, 0x34, 0xb4, 0x74, 0xf4, > + 0x0c, 0x8c, 0x4c, 0xcc, 0x2c, 0xac, 0x6c, 0xec, > + 0x1c, 0x9c, 0x5c, 0xdc, 0x3c, 0xbc, 0x7c, 0xfc, > + 0x02, 0x82, 0x42, 0xc2, 0x22, 0xa2, 0x62, 0xe2, > + 0x12, 0x92, 0x52, 0xd2, 0x32, 0xb2, 0x72, 0xf2, > + 0x0a, 0x8a, 0x4a, 0xca, 0x2a, 0xaa, 0x6a, 0xea, > + 0x1a, 0x9a, 0x5a, 0xda, 0x3a, 0xba, 0x7a, 0xfa, > + 0x06, 0x86, 0x46, 0xc6, 0x26, 0xa6, 0x66, 0xe6, > + 0x16, 0x96, 0x56, 0xd6, 0x36, 0xb6, 0x76, 0xf6, > + 0x0e, 0x8e, 0x4e, 0xce, 0x2e, 0xae, 0x6e, 0xee, > + 0x1e, 0x9e, 0x5e, 0xde, 0x3e, 0xbe, 0x7e, 0xfe, > + 0x01, 0x81, 0x41, 0xc1, 0x21, 0xa1, 0x61, 0xe1, > + 0x11, 0x91, 0x51, 0xd1, 0x31, 0xb1, 0x71, 0xf1, > + 0x09, 0x89, 0x49, 0xc9, 0x29, 0xa9, 0x69, 0xe9, > + 0x19, 0x99, 0x59, 0xd9, 0x39, 0xb9, 0x79, 0xf9, > + 0x05, 0x85, 0x45, 0xc5, 0x25, 0xa5, 0x65, 0xe5, > + 0x15, 0x95, 0x55, 0xd5, 0x35, 0xb5, 0x75, 0xf5, > + 0x0d, 0x8d, 0x4d, 0xcd, 0x2d, 0xad, 0x6d, 0xed, > + 0x1d, 0x9d, 0x5d, 0xdd, 0x3d, 0xbd, 0x7d, 0xfd, > + 0x03, 0x83, 0x43, 0xc3, 0x23, 0xa3, 0x63, 0xe3, > + 0x13, 0x93, 0x53, 0xd3, 0x33, 0xb3, 0x73, 0xf3, > + 0x0b, 0x8b, 0x4b, 0xcb, 0x2b, 0xab, 0x6b, 0xeb, > + 0x1b, 0x9b, 0x5b, 0xdb, 0x3b, 0xbb, 0x7b, 0xfb, > + 0x07, 0x87, 0x47, 0xc7, 0x27, 0xa7, 0x67, 0xe7, > + 0x17, 0x97, 0x57, 0xd7, 0x37, 0xb7, 0x77, 0xf7, > + 0x0f, 0x8f, 0x4f, 0xcf, 0x2f, 0xaf, 0x6f, 0xef, > + 0x1f, 0x9f, 0x5f, 0xdf, 0x3f, 0xbf, 0x7f, 0xff, > +}; > + > +static u8 swap_bits(struct bch_control *bch, u8 in) > +{ > + if (!bch->swap_bits) > + return in; > + > + return swap_bits_table[in]; > +} > + > /* > * same as bch_encode(), but process input data one byte at a time > */ > @@ -126,7 +169,9 @@ static void bch_encode_unaligned(struct bch_control *bch, > const int l = BCH_ECC_WORDS(bch)-1; > > while (len--) { > - p = bch->mod8_tab + (l+1)*(((ecc[0] >> 24)^(*data++)) & 0xff); > + u8 tmp = swap_bits(bch, *data++); > + > + p = bch->mod8_tab + (l+1)*(((ecc[0] >> 24)^(tmp)) & 0xff); > > for (i = 0; i < l; i++) > ecc[i] = ((ecc[i] << 8)|(ecc[i+1] >> 24))^(*p++); > @@ -145,10 +190,16 @@ static void load_ecc8(struct bch_control *bch, uint32_t *dst, > 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]; > + dst[i] = ((u32)swap_bits(bch, src[0]) << 24) | > + ((u32)swap_bits(bch, src[1]) << 16) | > + ((u32)swap_bits(bch, src[2]) << 8) | > + swap_bits(bch, src[3]); > > memcpy(pad, src, BCH_ECC_BYTES(bch)-4*nwords); > - dst[nwords] = (pad[0] << 24)|(pad[1] << 16)|(pad[2] << 8)|pad[3]; > + dst[nwords] = ((u32)swap_bits(bch, pad[0]) << 24) | > + ((u32)swap_bits(bch, pad[1]) << 16) | > + ((u32)swap_bits(bch, pad[2]) << 8) | > + swap_bits(bch, pad[3]); > } > > /* > @@ -161,15 +212,15 @@ static void store_ecc8(struct bch_control *bch, uint8_t *dst, > 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; > + *dst++ = swap_bits(bch, src[i] >> 24); > + *dst++ = swap_bits(bch, src[i] >> 16); > + *dst++ = swap_bits(bch, src[i] >> 8); > + *dst++ = swap_bits(bch, src[i]); > } > - pad[0] = (src[nwords] >> 24); > - pad[1] = (src[nwords] >> 16) & 0xff; > - pad[2] = (src[nwords] >> 8) & 0xff; > - pad[3] = (src[nwords] >> 0) & 0xff; > + pad[0] = swap_bits(bch, src[nwords] >> 24); > + pad[1] = swap_bits(bch, src[nwords] >> 16); > + pad[2] = swap_bits(bch, src[nwords] >> 8); > + pad[3] = swap_bits(bch, src[nwords]); > memcpy(dst, pad, BCH_ECC_BYTES(bch)-4*nwords); > } > > @@ -240,7 +291,13 @@ void bch_encode(struct bch_control *bch, const uint8_t *data, > */ > while (mlen--) { > /* input data is read in big-endian format */ > - w = r[0]^cpu_to_be32(*pdata++); > + w = cpu_to_be32(*pdata++); > + if (bch->swap_bits) > + w = (u32)swap_bits(bch, w) | > + ((u32)swap_bits(bch, w >> 8) << 8) | > + ((u32)swap_bits(bch, w >> 16) << 16) | > + ((u32)swap_bits(bch, w >> 24) << 24); > + w ^= r[0]; > p0 = tab0 + (l+1)*((w >> 0) & 0xff); > p1 = tab1 + (l+1)*((w >> 8) & 0xff); > p2 = tab2 + (l+1)*((w >> 16) & 0xff); > @@ -1048,7 +1105,9 @@ int bch_decode(struct bch_control *bch, const uint8_t *data, unsigned int len, > break; > } > errloc[i] = nbits-1-errloc[i]; > - errloc[i] = (errloc[i] & ~7)|(7-(errloc[i] & 7)); > + if (!bch->swap_bits) > + errloc[i] = (errloc[i] & ~7) | > + (7-(errloc[i] & 7)); > } > } > return (err >= 0) ? err : -EBADMSG; > @@ -1240,6 +1299,7 @@ static uint32_t *compute_generator_polynomial(struct bch_control *bch) > * @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) > + * @swap_bits: swap bits within data and syndrome bytes > * > * Returns: > * a newly allocated BCH control structure if successful, NULL otherwise > @@ -1256,7 +1316,8 @@ static uint32_t *compute_generator_polynomial(struct bch_control *bch) > * BCH control structure, ecc length in bytes is given by member @ecc_bytes of > * the structure. > */ > -struct bch_control *bch_init(int m, int t, unsigned int prim_poly) > +struct bch_control *bch_init(int m, int t, unsigned int prim_poly, > + bool swap_bits) > { > int err = 0; > unsigned int i, words; > @@ -1321,6 +1382,7 @@ struct bch_control *bch_init(int m, int t, unsigned int prim_poly) > 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); > + bch->swap_bits = swap_bits; > > for (i = 0; i < ARRAY_SIZE(bch->poly_2t); i++) > bch->poly_2t[i] = bch_alloc(GF_POLY_SZ(2*t), &err); ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/