From mboxrd@z Thu Jan 1 00:00:00 1970 From: plagnioj@jcrosoft.com (Jean-Christophe PLAGNIOL-VILLARD) Date: Tue, 9 Oct 2012 13:50:23 +0200 Subject: [PATCH 10/11] fsmc/nand: Add sw bch support for ecc calculation/correction In-Reply-To: <3968b65e9aa0a81eca16ce0f20e45504da7ad7fe.1349778821.git.vipin.kumar@st.com> References: <3968b65e9aa0a81eca16ce0f20e45504da7ad7fe.1349778821.git.vipin.kumar@st.com> Message-ID: <20121009115023.GK12801@game.jcrosoft.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 16:14 Tue 09 Oct , Vipin Kumar wrote: > Signed-off-by: Vipin Kumar > --- > .../devicetree/bindings/mtd/fsmc-nand.txt | 2 + > drivers/mtd/nand/fsmc_nand.c | 156 +++++++++++++-------- > include/linux/mtd/fsmc.h | 3 + > 3 files changed, 106 insertions(+), 55 deletions(-) > > diff --git a/Documentation/devicetree/bindings/mtd/fsmc-nand.txt b/Documentation/devicetree/bindings/mtd/fsmc-nand.txt > index 598bca2..dcf513b 100644 > --- a/Documentation/devicetree/bindings/mtd/fsmc-nand.txt > +++ b/Documentation/devicetree/bindings/mtd/fsmc-nand.txt > @@ -30,6 +30,8 @@ Optional properties: > - st,rb-gpios: When the st,ready-busy is defined as "rb-gpio", a gpio > pin number is defined in this property > > +- nand-sw-ecc: boolean indicating whether s/w ecc is supported > + please use the generic binding - nand-ecc-mode = xx > Example: > > fsmc: flash at d1800000 { > diff --git a/drivers/mtd/nand/fsmc_nand.c b/drivers/mtd/nand/fsmc_nand.c > index 762cf83..ff84468 100644 > --- a/drivers/mtd/nand/fsmc_nand.c > +++ b/drivers/mtd/nand/fsmc_nand.c > @@ -946,6 +946,9 @@ static int __devinit fsmc_nand_probe_config_dt(struct platform_device *pdev, > } else > pdata->rbpin.use_pin = FSMC_RB_WAIT; > > + if (of_property_read_bool(np, "nand-sw-ecc")) > + pdata->sw_ecc = true; > + of_get_nand_ecc_mode > return 0; > } > #else > @@ -972,6 +975,7 @@ static int __init fsmc_nand_probe(struct platform_device *pdev) > dma_cap_mask_t mask; > int ret = 0; > u32 pid, bank; > + uint oobeccsize, m; > int i; > > if (np) { > @@ -1104,9 +1108,24 @@ static int __init fsmc_nand_probe(struct platform_device *pdev) > nand->cmd_ctrl = fsmc_cmd_ctrl; > nand->chip_delay = 30; > > - nand->ecc.mode = NAND_ECC_HW; > - nand->ecc.hwctl = fsmc_enable_hwecc; > - nand->ecc.size = 512; > + if (pdata->sw_ecc) { > + nand->ecc.mode = NAND_ECC_SOFT_BCH; > + /* > + * The recent devices require n-bit correctibility in x bytes. > + * The values of n and x varies as below > + * n - 1 to 100 > + * x - 512 to 1K > + * TODO: For now, take x = 1K for all sw bch mathematics. Think > + * of a better way to handle other device dependent > + * requirements. May be it should come from board dts files > + */ > + nand->ecc.size = 1024; > + } else { > + nand->ecc.mode = NAND_ECC_HW; > + nand->ecc.hwctl = fsmc_enable_hwecc; > + nand->ecc.size = 512; > + } > + > nand->options = pdata->options; > nand->select_chip = fsmc_select_chip; > nand->badblockbits = 7; > @@ -1165,17 +1184,19 @@ static int __init fsmc_nand_probe(struct platform_device *pdev) > nand->options & NAND_BUSWIDTH_16, > host->dev_timings, host->rbpin); > > - if (AMBA_REV_BITS(host->pid) >= 8) { > - nand->ecc.read_page = fsmc_read_page_hwecc; > - nand->ecc.calculate = fsmc_read_hwecc_ecc4; > - nand->ecc.correct = fsmc_bch8_correct_data; > - nand->ecc.bytes = 13; > - nand->ecc.strength = 8; > - } else { > - nand->ecc.calculate = fsmc_read_hwecc_ecc1; > - nand->ecc.correct = nand_correct_data; > - nand->ecc.bytes = 3; > - nand->ecc.strength = 1; > + if (nand->ecc.mode != NAND_ECC_SOFT_BCH) { > + if (AMBA_REV_BITS(host->pid) >= 8) { > + nand->ecc.read_page = fsmc_read_page_hwecc; > + nand->ecc.calculate = fsmc_read_hwecc_ecc4; > + nand->ecc.correct = fsmc_bch8_correct_data; > + nand->ecc.bytes = 13; > + nand->ecc.strength = 8; > + } else { > + nand->ecc.calculate = fsmc_read_hwecc_ecc1; > + nand->ecc.correct = nand_correct_data; > + nand->ecc.bytes = 3; > + nand->ecc.strength = 1; > + } > } > > /* > @@ -1187,48 +1208,73 @@ static int __init fsmc_nand_probe(struct platform_device *pdev) > goto err_scan_ident; > } > > - if (AMBA_REV_BITS(host->pid) >= 8) { > - switch (host->mtd.oobsize) { > - case 16: > - nand->ecc.layout = &fsmc_ecc4_16_layout; > - host->ecc_place = &fsmc_ecc4_sp_place; > - break; > - case 64: > - nand->ecc.layout = &fsmc_ecc4_64_layout; > - host->ecc_place = &fsmc_ecc4_lp_place; > - break; > - case 128: > - nand->ecc.layout = &fsmc_ecc4_128_layout; > - host->ecc_place = &fsmc_ecc4_lp_place; > - break; > - case 224: > - nand->ecc.layout = &fsmc_ecc4_224_layout; > - host->ecc_place = &fsmc_ecc4_lp_place; > - break; > - case 256: > - nand->ecc.layout = &fsmc_ecc4_256_layout; > - host->ecc_place = &fsmc_ecc4_lp_place; > - break; > - default: > - printk(KERN_WARNING "No oob scheme defined for " > - "oobsize %d\n", mtd->oobsize); > - BUG(); > - } > + if (nand->ecc.mode == NAND_ECC_SOFT_BCH) { > + /* > + * Initialize the ecc bytes and strength dynamically based on eccsize > + * and writesize. > + * > + * Parameters @eccsize and @eccbytes are used to compute BCH parameters > + * m (Galois field order) and t (error correction capability). @eccbytes > + * should be equal to the number of bytes required to store m*t bits, > + * where m is such that 2^m-1 > @eccsize*8. > + * > + * Example: to configure 4 bit correction per 512 bytes, you should pass > + * @eccsize = 512 (thus, m=13 is the smallest integer such that 2^m-1 > > + * 512*8) @eccbytes = 7 (7 bytes are required to store m*t = 13*4 = 52 > + * bits) > + * > + * Note: 2 bytes of oob are considered reserved for bad block marking > + */ > + m = fls(1 + 8 * nand->ecc.size); > + oobeccsize = ((host->mtd.oobsize - 2) * \ > + nand->ecc.size) / host->mtd.writesize; > + nand->ecc.bytes = (oobeccsize / m) * m; > + nand->ecc.strength = (nand->ecc.bytes * 8) / m; > + nand->ecc.layout = NULL; > } else { > - switch (host->mtd.oobsize) { > - case 16: > - nand->ecc.layout = &fsmc_ecc1_16_layout; > - break; > - case 64: > - nand->ecc.layout = &fsmc_ecc1_64_layout; > - break; > - case 128: > - nand->ecc.layout = &fsmc_ecc1_128_layout; > - break; > - default: > - printk(KERN_WARNING "No oob scheme defined for " > - "oobsize %d\n", mtd->oobsize); > - BUG(); > + if (AMBA_REV_BITS(host->pid) >= 8) { > + switch (host->mtd.oobsize) { > + case 16: > + nand->ecc.layout = &fsmc_ecc4_16_layout; > + host->ecc_place = &fsmc_ecc4_sp_place; > + break; > + case 64: > + nand->ecc.layout = &fsmc_ecc4_64_layout; > + host->ecc_place = &fsmc_ecc4_lp_place; > + break; > + case 128: > + nand->ecc.layout = &fsmc_ecc4_128_layout; > + host->ecc_place = &fsmc_ecc4_lp_place; > + break; > + case 224: > + nand->ecc.layout = &fsmc_ecc4_224_layout; > + host->ecc_place = &fsmc_ecc4_lp_place; > + break; > + case 256: > + nand->ecc.layout = &fsmc_ecc4_256_layout; > + host->ecc_place = &fsmc_ecc4_lp_place; > + break; > + default: > + printk(KERN_WARNING "No oob scheme defined for " > + "oobsize %d\n", mtd->oobsize); > + BUG(); > + } > + } else { > + switch (host->mtd.oobsize) { > + case 16: > + nand->ecc.layout = &fsmc_ecc1_16_layout; > + break; > + case 64: > + nand->ecc.layout = &fsmc_ecc1_64_layout; > + break; > + case 128: > + nand->ecc.layout = &fsmc_ecc1_128_layout; > + break; > + default: > + printk(KERN_WARNING "No oob scheme defined for " > + "oobsize %d\n", mtd->oobsize); > + BUG(); > + } > } > } > > diff --git a/include/linux/mtd/fsmc.h b/include/linux/mtd/fsmc.h > index eed22a1..07eee6e 100644 > --- a/include/linux/mtd/fsmc.h > +++ b/include/linux/mtd/fsmc.h > @@ -176,6 +176,9 @@ struct fsmc_nand_platform_data { > /* priv structures for dma accesses */ > void *read_dma_priv; > void *write_dma_priv; > + > + /* whether s/w ecc is supported */ > + bool sw_ecc; > }; > > extern int __init fsmc_nor_init(struct platform_device *pdev, > -- > 1.7.11.4 >