From mboxrd@z Thu Jan 1 00:00:00 1970 From: Felipe Balbi Subject: Re: [PATCH v8 4/6] mtd:nand:omap2: updated support for BCH4 ECC scheme Date: Fri, 11 Oct 2013 10:55:53 -0500 Message-ID: <20131011155553.GS25706@radagast> References: <1381498603-15715-1-git-send-email-pekon@ti.com> <1381498603-15715-5-git-send-email-pekon@ti.com> Reply-To: Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="80Ds8Z/hZmemMosa" Return-path: Content-Disposition: inline In-Reply-To: <1381498603-15715-5-git-send-email-pekon@ti.com> Sender: linux-omap-owner@vger.kernel.org To: Pekon Gupta Cc: mark.rutland@arm.com, robherring2@gmail.com, olof@lixom.net, computersforpeace@gmail.com, dedekind1@gmail.com, Pawel.Moll@arm.com, ijc+devicetree@hellion.org.uk, swarren@wwwdotorg.org, dwmw2@infradead.org, arnd@arndb.de, tony@atomide.com, bcousson@baylibre.com, avinashphilipk@gmail.com, balbi@ti.com, linux-mtd@lists.infradead.org, linux-omap@vger.kernel.org, devicetree@vger.kernel.org, Andrew Morton List-Id: devicetree@vger.kernel.org --80Ds8Z/hZmemMosa Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Oct 11, 2013 at 07:06:41PM +0530, Pekon Gupta wrote: > This patch adds following two flavours of BCH4 ECC scheme in omap2-nand d= river > - OMAP_ECC_BCH4_CODE_HW_DETECTION_SW > - uses GPMC H/W engine for calculating ECC. > - uses software library (lib/bch.h & nand_bch.h) for error correction. >=20 > - OMAP_ECC_BCH4_CODE_HW > - uses GPMC H/W engine for calculating ECC. > - uses ELM H/W engine for error correction. >=20 > With this patch omap2-nand driver supports following ECC schemes: > +---------------------------------------+---------------+---------------+ > | ECC scheme |ECC calculation|Error detection| > +---------------------------------------+---------------+---------------+ > |OMAP_ECC_HAM1_CODE_HW |H/W (GPMC) |S/W | > +---------------------------------------+---------------+---------------+ > |OMAP_ECC_BCH4_CODE_HW_DETECTION_SW |H/W (GPMC) |S/W (lib/bch.h)| > |OMAP_ECC_BCH4_CODE_HW |H/W (GPMC) |H/W (ELM) | > +---------------------------------------+---------------+---------------+ > |OMAP_ECC_BCH8_CODE_HW_DETECTION_SW |H/W (GPMC) |S/W (lib/bch.h)| > |OMAP_ECC_BCH8_CODE_HW |H/W (GPMC) |H/W (ELM) | > +---------------------------------------+---------------+---------------+ > Important: > - Selection of OMAP_ECC_BCHx_CODE_HW_DETECTION_SW requires, > Kconfig: CONFIG_MTD_NAND_ECC_BCH: enables S/W based BCH ECC algorithm. >=20 > - Selection of OMAP_ECC_BCHx_CODE_HW requires, > Kconfig: CONFIG_MTD_NAND_OMAP_BCH: enables ELM H/W module. >=20 > Signed-off-by: Pekon Gupta Reviewed-by: Felipe Balbi > --- > drivers/mtd/nand/Kconfig | 30 ++--------- > drivers/mtd/nand/omap2.c | 134 +++++++++++++++++++++--------------------= ------ > 2 files changed, 63 insertions(+), 101 deletions(-) >=20 > diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig > index d885298..5836039 100644 > --- a/drivers/mtd/nand/Kconfig > +++ b/drivers/mtd/nand/Kconfig > @@ -96,35 +96,13 @@ config MTD_NAND_OMAP2 > =20 > config MTD_NAND_OMAP_BCH > depends on MTD_NAND && MTD_NAND_OMAP2 && ARCH_OMAP3 > - tristate "Enable support for hardware BCH error correction" > + tristate "Support hardware based BCH error correction" > default n > select BCH > - select BCH_CONST_PARAMS > help > - Support for hardware BCH error correction. > - > -choice > - prompt "BCH error correction capability" > - depends on MTD_NAND_OMAP_BCH > - > -config MTD_NAND_OMAP_BCH8 > - bool "8 bits / 512 bytes (recommended)" > - help > - Support correcting up to 8 bitflips per 512-byte block. > - This will use 13 bytes of spare area per 512 bytes of page data. > - This is the recommended mode, as 4-bit mode does not work > - on some OMAP3 revisions, due to a hardware bug. > - > -config MTD_NAND_OMAP_BCH4 > - bool "4 bits / 512 bytes" > - help > - Support correcting up to 4 bitflips per 512-byte block. > - This will use 7 bytes of spare area per 512 bytes of page data. > - Note that this mode does not work on some OMAP3 revisions, due to a > - hardware bug. Please check your OMAP datasheet before selecting this > - mode. > - > -endchoice > + Some devices have built-in ELM hardware engine, which can be used to > + locate and correct errors when using BCH ECC scheme. This enables the > + driver support for same. > =20 > if MTD_NAND_OMAP_BCH > config BCH_CONST_M > diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c > index fb96251..a783dae 100644 > --- a/drivers/mtd/nand/omap2.c > +++ b/drivers/mtd/nand/omap2.c > @@ -27,6 +27,7 @@ > =20 > #ifdef CONFIG_MTD_NAND_ECC_BCH > #include > +#include > #endif > #ifdef CONFIG_MTD_NAND_OMAP_BCH > #include > @@ -144,7 +145,6 @@ > #define BCH_ECC_SIZE1 0x20 /* ecc_size1 =3D 32 */ > =20 > #define BADBLOCK_MARKER_LENGTH 2 > -#define OMAP_ECC_BCH8_POLYNOMIAL 0x201b > =20 > #ifdef CONFIG_MTD_NAND_OMAP_BCH > static u_char bch8_vector[] =3D {0xf3, 0xdb, 0x14, 0x16, 0x8b, 0xd2, 0xb= e, 0xcc, > @@ -188,7 +188,6 @@ struct omap_nand_info { > int buf_len; > struct gpmc_nand_regs reg; > /* fields specific for BCHx_HW ECC scheme */ > - struct bch_control *bch; > bool is_elm_used; > struct device *elm_dev; > struct device_node *of_node; > @@ -1522,43 +1521,7 @@ static int omap_elm_correct_data(struct mtd_info *= mtd, u_char *data, > =20 > return stat; > } > -#endif /* CONFIG_MTD_NAND_OMAP_BCH */ > =20 > -#ifdef CONFIG_MTD_NAND_ECC_BCH > -/** > - * omap3_correct_data_bch - Decode received data and correct errors > - * @mtd: MTD device structure > - * @data: page data > - * @read_ecc: ecc read from nand flash > - * @calc_ecc: ecc read from HW ECC registers > - */ > -static int omap3_correct_data_bch(struct mtd_info *mtd, u_char *data, > - u_char *read_ecc, u_char *calc_ecc) > -{ > - int i, count; > - /* cannot correct more than 8 errors */ > - unsigned int errloc[8]; > - struct omap_nand_info *info =3D container_of(mtd, struct omap_nand_info, > - mtd); > - > - count =3D decode_bch(info->bch, NULL, 512, read_ecc, calc_ecc, NULL, > - errloc); > - if (count > 0) { > - /* correct errors */ > - for (i =3D 0; i < count; i++) { > - /* correct data only, not ecc bytes */ > - if (errloc[i] < 8*512) > - data[errloc[i]/8] ^=3D 1 << (errloc[i] & 7); > - pr_debug("corrected bitflip %u\n", errloc[i]); > - } > - } else if (count < 0) { > - pr_err("ecc unrecoverable error\n"); > - } > - return count; > -} > -#endif /* CONFIG_MTD_NAND_ECC_BCH */ > - > -#ifdef CONFIG_MTD_NAND_OMAP_BCH > /** > * omap_write_page_bch - BCH ecc based write page function for entire pa= ge > * @mtd: mtd info structure > @@ -1675,28 +1638,6 @@ static int is_elm_present(struct omap_nand_info *i= nfo, > } > #endif /* CONFIG_MTD_NAND_ECC_BCH */ > =20 > -#ifdef CONFIG_MTD_NAND_ECC_BCH > -/** > - * omap3_free_bch - Release BCH ecc resources > - * @mtd: MTD device structure > - */ > -static void omap3_free_bch(struct mtd_info *mtd) > -{ > - struct omap_nand_info *info =3D container_of(mtd, struct omap_nand_info, > - mtd); > - if (info->bch) { > - free_bch(info->bch); > - info->bch =3D NULL; > - } > -} > - > -#else > - > -static void omap3_free_bch(struct mtd_info *mtd) > -{ > -} > -#endif /* CONFIG_MTD_NAND_ECC_BCH */ > - > static int omap_nand_probe(struct platform_device *pdev) > { > struct omap_nand_info *info; > @@ -1731,10 +1672,10 @@ static int omap_nand_probe(struct platform_device= *pdev) > mtd->owner =3D THIS_MODULE; > mtd->priv =3D &info->nand; > nand_chip =3D &info->nand; > + nand_chip->ecc.priv =3D NULL; > info->pdev =3D pdev; > info->gpmc_cs =3D pdata->cs; > info->reg =3D pdata->reg; > - info->bch =3D NULL; > =20 > nand_chip->options |=3D NAND_SKIP_BBTSCAN | NAND_BUSWIDTH_AUTO; > info->of_node =3D pdata->of_node; > @@ -1927,7 +1868,7 @@ static int omap_nand_probe(struct platform_device *= pdev) > nand_chip->ecc.bytes =3D 7; > nand_chip->ecc.strength =3D 4; > nand_chip->ecc.hwctl =3D omap3_enable_hwecc_bch; > - nand_chip->ecc.correct =3D omap3_correct_data_bch; > + info->nand.ecc.correct =3D nand_bch_correct_data; > nand_chip->ecc.calculate =3D omap3_calculate_ecc_bch4; > /* define custom ECC layout */ > ecclayout->eccbytes =3D nand_chip->ecc.bytes * > @@ -1937,10 +1878,11 @@ static int omap_nand_probe(struct platform_device= *pdev) > ecclayout->oobfree->offset =3D ecclayout->eccpos[0] + > ecclayout->eccbytes; > /* software bch library is used for locating errors */ > - info->bch =3D init_bch(nand_chip->ecc.bytes, > - nand_chip->ecc.strength, > - OMAP_ECC_BCH8_POLYNOMIAL); > - if (!info->bch) { > + info->nand.ecc.priv =3D nand_bch_init(mtd, > + info->nand.ecc.size, > + info->nand.ecc.bytes, > + &info->nand.ecc.layout); > + if (!info->nand.ecc.priv) { > pr_err("nand: error: unable to use s/w BCH library\n"); > err =3D -EINVAL; > } > @@ -1951,6 +1893,39 @@ static int omap_nand_probe(struct platform_device = *pdev) > goto out_release_mem_region; > #endif > =20 > + case OMAP_ECC_BCH4_CODE_HW: > +#ifdef CONFIG_MTD_NAND_OMAP_BCH > + pr_info("nand: using OMAP_ECC_BCH4_CODE_HW ECC scheme\n"); > + info->nand.ecc.mode =3D NAND_ECC_HW; > + info->nand.ecc.size =3D 512; > + /* 14th bit is kept reserved for ROM-code compatibility */ > + info->nand.ecc.bytes =3D 7 + 1; > + info->nand.ecc.strength =3D 4; > + info->nand.ecc.hwctl =3D omap3_enable_hwecc_bch; > + info->nand.ecc.correct =3D omap_elm_correct_data; > + info->nand.ecc.calculate =3D omap3_calculate_ecc_bch; > + info->nand.ecc.read_page =3D omap_read_page_bch; > + info->nand.ecc.write_page =3D omap_write_page_bch; > + /* This ECC scheme requires ELM H/W block */ > + if (is_elm_present(info, pdata->elm_of_node, BCH4_ECC) < 0) { > + pr_err("nand: error: could not initialize ELM\n"); > + err =3D -ENODEV; > + goto out_release_mem_region; > + } > + /* define ECC layout */ > + ecclayout->eccbytes =3D info->nand.ecc.bytes * > + (mtd->writesize / > + info->nand.ecc.size); > + ecclayout->eccpos[0] =3D BADBLOCK_MARKER_LENGTH; > + ecclayout->oobfree->offset =3D ecclayout->eccpos[0] + > + ecclayout->eccbytes; > + break; > +#else > + pr_err("nand: error: CONFIG_MTD_NAND_OMAP_BCH not enabled\n"); > + err =3D -EINVAL; > + goto out_release_mem_region; > +#endif > + > case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW: > #ifdef CONFIG_MTD_NAND_ECC_BCH > pr_info("nand: using OMAP_ECC_BCH8_CODE_HW_DETECTION_SW\n"); > @@ -1959,7 +1934,7 @@ static int omap_nand_probe(struct platform_device *= pdev) > nand_chip->ecc.bytes =3D 13; > nand_chip->ecc.strength =3D 8; > nand_chip->ecc.hwctl =3D omap3_enable_hwecc_bch; > - nand_chip->ecc.correct =3D omap3_correct_data_bch; > + info->nand.ecc.correct =3D nand_bch_correct_data; > nand_chip->ecc.calculate =3D omap3_calculate_ecc_bch8; > /* define custom ECC layout */ > ecclayout->eccbytes =3D nand_chip->ecc.bytes * > @@ -1969,10 +1944,11 @@ static int omap_nand_probe(struct platform_device= *pdev) > ecclayout->oobfree->offset =3D ecclayout->eccpos[0] + > ecclayout->eccbytes; > /* software bch library is used for locating errors */ > - info->bch =3D init_bch(nand_chip->ecc.bytes, > - nand_chip->ecc.strength, > - OMAP_ECC_BCH8_POLYNOMIAL); > - if (!info->bch) { > + info->nand.ecc.priv =3D nand_bch_init(mtd, > + info->nand.ecc.size, > + info->nand.ecc.bytes, > + &info->nand.ecc.layout); > + if (!info->nand.ecc.priv) { > pr_err("nand: error: unable to use s/w BCH library\n"); > err =3D -EINVAL; > goto out_release_mem_region; > @@ -2023,7 +1999,6 @@ static int omap_nand_probe(struct platform_device *= pdev) > } > =20 > /* populate remaining info for custom ecc layout */ > - pr_info("%s: using custom ecc layout\n", DRIVER_NAME); > ecclayout->oobfree->length =3D mtd->oobsize - BADBLOCK_MARKER_LENGTH > - ecclayout->eccbytes; > if (!(nand_chip->options & NAND_BUSWIDTH_16)) > @@ -2061,7 +2036,12 @@ out_release_mem_region: > free_irq(info->gpmc_irq_fifo, info); > release_mem_region(info->phys_base, info->mem_size); > out_free_info: > - omap3_free_bch(&info->mtd); > +#ifdef CONFIG_MTD_NAND_ECC_BCH > + if (info->nand.ecc.priv) { > + nand_bch_free(info->nand.ecc.priv); > + info->nand.ecc.priv =3D NULL; > + } > +#endif > kfree(info); > =20 > return err; > @@ -2072,8 +2052,12 @@ static int omap_nand_remove(struct platform_device= *pdev) > struct mtd_info *mtd =3D platform_get_drvdata(pdev); > struct omap_nand_info *info =3D container_of(mtd, struct omap_nand_info, > mtd); > - omap3_free_bch(&info->mtd); > - > +#ifdef CONFIG_MTD_NAND_ECC_BCH > + if (info->nand.ecc.priv) { > + nand_bch_free(info->nand.ecc.priv); > + info->nand.ecc.priv =3D NULL; > + } > +#endif > if (info->dma) > dma_release_channel(info->dma); > =20 > --=20 > 1.8.1 >=20 --=20 balbi --80Ds8Z/hZmemMosa Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIcBAEBAgAGBQJSWB+JAAoJEIaOsuA1yqREyzUQAKAXJk79pF46obh9m4Ypi4kJ UQjRDqnXeHqjfs/CLHY0pdnG9eo8F8sAeRDBmgeyR0f471FVMRZKEVtfzMprFctY gr9LO651JMz5UnJeJ3Y/cf6sLI2zQOlAj2Mve54V+oeoW+faL25dJMeXMcqfa5Mj IDZS1NHDbVEjZPQOcEu94Qr9lq1s2+pF/XxJDA2ekyDLCYrsyvCpTACvvWnrxaZG 4GfjpF4qUarYbvs4632Bsfg8xVpLlx6E2cE7jNa4u0KVPVTfxh1spLFRazne2rSn OAKSSERAE1pVntdVNqxMPM4WVsWIQ4YvG6lqHUBRT8ii3IfmuiZgShtalJpEoPAP y4MVXic8Sm8m3hHtxx3DksO0vI57BS2povOSizY5gU+Vo1kp+OWByBfZwQSrQClW C3qXVsDBXosL7KgB9djLpSDm5bsQs2WYfdyfL3wmOJFes9/A7sd5EFyHmQAXdmoj GjzaVcw6+9s4eRpZKbujp3vIfZuNqtmmbA9+AU7x4sMAdpkxFhsFrBMVlC/RaOlY FNa8DJoqiToRsFm5jd6UD7wOuccoy3JDROtcjIqe457QGUdU1FkEiTs2oN6qGMKh jgPTQqpnAfY2zVg8afitm1Cd67uMozhLi8VN78StUXXy6ZdgKTB8j05lpW90ZZ13 MVMYU2irf/pD/lsXHAGu =CZw4 -----END PGP SIGNATURE----- --80Ds8Z/hZmemMosa--