| Message ID | 1381816197-20477-8-git-send-email-pekon@ti.com |
|---|---|
| State | New, archived |
| Headers | show |
+ Ivan, as he has touched this stuff before On Tue, Oct 15, 2013 at 11:19:55AM +0530, Pekon Gupta wrote: > generic frame-work in mtd/nand/nand_bch.c is a wrapper above lib/bch.h which > encapsulates all control information specific to BCH ecc algorithm in software. > Thus this patch: > (1) replace omap specific implementations with equivalent wrapper in nand_bch.c > so that more generic code is re-used. like; > omap3_correct_data_bch() -> nand_bch_correct_data() > omap3_free_bch() -> nand_bch_free() > (2) replace direct calls to lib/bch.c with wrapper functions defined in nand_bch.c > init_bch() -> nand_bch_init() > (3) removes selection between BCH8 and BCH4 h/w ecc-schemes via KConfig. > This selection is now based on ti,nand-ecc-opt and ti,elm-id DT bindings. > > Signed-off-by: Pekon Gupta <pekon@ti.com> > --- > drivers/mtd/nand/Kconfig | 30 ++------------- > drivers/mtd/nand/omap2.c | 96 +++++++++++------------------------------------- > 2 files changed, 26 insertions(+), 100 deletions(-) > > 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 > > 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 Do you know what will happen now if someone configures BCH_CONST_PARAMS? Would this cause problems? > 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. > > if MTD_NAND_OMAP_BCH > config BCH_CONST_M Do you need to to also kill of the Kconfig stuff for BCH_CONST_M and BCH_CONST_T, which were tied to the MTD_NAND_OMAP_BCH4 and MTD_NAND_OMAP_BCH8 configs you just removed? > diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c > index 5f6e621..769ff65 100644 > --- a/drivers/mtd/nand/omap2.c > +++ b/drivers/mtd/nand/omap2.c > @@ -25,7 +25,7 @@ > #include <linux/of.h> > #include <linux/of_device.h> > > -#include <linux/bch.h> > +#include <linux/mtd/nand_bch.h> > #include <linux/platform_data/elm.h> > > #include <linux/platform_data/mtd-nand-omap2.h> > @@ -140,7 +140,6 @@ > #define BCH_ECC_SIZE1 0x20 /* ecc_size1 = 32 */ > > #define BADBLOCK_MARKER_LENGTH 2 > -#define OMAP_ECC_BCH8_POLYNOMIAL 0x201b > > #ifdef CONFIG_MTD_NAND_OMAP_BCH > static u_char bch8_vector[] = {0xf3, 0xdb, 0x14, 0x16, 0x8b, 0xd2, 0xbe, 0xcc, > @@ -173,7 +172,6 @@ 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; > @@ -1507,43 +1505,7 @@ static int omap_elm_correct_data(struct mtd_info *mtd, u_char *data, > > return stat; > } > -#endif /* CONFIG_MTD_NAND_OMAP_BCH */ > > -#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 = container_of(mtd, struct omap_nand_info, > - mtd); > - > - count = decode_bch(info->bch, NULL, 512, read_ecc, calc_ecc, NULL, > - errloc); > - if (count > 0) { > - /* correct errors */ > - for (i = 0; i < count; i++) { > - /* correct data only, not ecc bytes */ > - if (errloc[i] < 8*512) > - data[errloc[i]/8] ^= 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 page > * @mtd: mtd info structure > @@ -1660,28 +1622,6 @@ static int is_elm_present(struct omap_nand_info *info, > } > #endif /* CONFIG_MTD_NAND_ECC_BCH */ > > -#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 = container_of(mtd, struct omap_nand_info, > - mtd); > - if (info->bch) { > - free_bch(info->bch); > - info->bch = 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; > @@ -1714,13 +1654,13 @@ static int omap_nand_probe(struct platform_device *pdev) > info->pdev = pdev; > info->gpmc_cs = pdata->cs; > info->reg = pdata->reg; > - info->bch = NULL; > info->of_node = pdata->of_node; > mtd = &info->mtd; > mtd->priv = &info->nand; > mtd->name = dev_name(&pdev->dev); > mtd->owner = THIS_MODULE; > nand_chip = &info->nand; > + nand_chip->ecc.priv = NULL; > nand_chip->options |= NAND_SKIP_BBTSCAN | NAND_BUSWIDTH_AUTO; > > res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > @@ -1910,7 +1850,7 @@ static int omap_nand_probe(struct platform_device *pdev) > nand_chip->ecc.bytes = 7; > nand_chip->ecc.strength = 4; > nand_chip->ecc.hwctl = omap3_enable_hwecc_bch; > - nand_chip->ecc.correct = omap3_correct_data_bch; > + info->nand.ecc.correct = nand_bch_correct_data; > nand_chip->ecc.calculate = omap3_calculate_ecc_bch4; > /* define ECC layout */ > ecclayout->eccbytes = nand_chip->ecc.bytes * > @@ -1920,10 +1860,11 @@ static int omap_nand_probe(struct platform_device *pdev) > ecclayout->oobfree->offset = ecclayout->eccpos[0] + > ecclayout->eccbytes; > /* software bch library is used for locating errors */ > - info->bch = init_bch(nand_chip->ecc.bytes, > - nand_chip->ecc.strength, > - OMAP_ECC_BCH8_POLYNOMIAL); > - if (!info->bch) { > + info->nand.ecc.priv = nand_bch_init(mtd, > + info->nand.ecc.size, > + info->nand.ecc.bytes, > + &info->nand.ecc.layout); Are you sure nand_bch_init() is a proper drop-in replacement for the implementation you had based on init_bch()? It looks to me like they at least use a differnt polynomial value (0x201b vs. 0). Is this a problem for backwards compatibility? > + if (!info->nand.ecc.priv) { > pr_err("nand: error: unable to use s/w BCH library\n"); > err = -EINVAL; > } [...] > @@ -1985,10 +1926,11 @@ static int omap_nand_probe(struct platform_device *pdev) > ecclayout->oobfree->offset = ecclayout->eccpos[0] + > ecclayout->eccbytes; > /* software bch library is used for locating errors */ > - info->bch = init_bch(nand_chip->ecc.bytes, > - nand_chip->ecc.strength, > - OMAP_ECC_BCH8_POLYNOMIAL); > - if (!info->bch) { > + info->nand.ecc.priv = nand_bch_init(mtd, > + info->nand.ecc.size, > + info->nand.ecc.bytes, > + &info->nand.ecc.layout); Same questions apply. > + if (!info->nand.ecc.priv) { > pr_err("nand: error: unable to use s/w BCH library\n"); > err = -EINVAL; > goto out_release_mem_region; [...] A related question: do we have any current users of this driver that can provide testing results for this series? Or is this work just tested with new hardware? Brian
> From: Brian Norris [mailto:computersforpeace@gmail.com] > > On Tue, Oct 15, 2013 at 11:19:55AM +0530, Pekon Gupta wrote: [snip] > > 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 > > > > 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 > > Do you know what will happen now if someone configures > BCH_CONST_PARAMS? > Would this cause problems? > As per comments in lib/bch.c --------------------------- * Option CONFIG_BCH_CONST_PARAMS can be used to force fixed values of * parameters m and t; thus allowing extra compiler optimizations and providing * better (up to 2x) encoding performance. Using this option makes sense when * (m,t) are fixed and known in advance, e.g. when using BCH error correction * on a particular NAND flash device. --------------------------- 'BCH_CONST_PARAMS' is required for optimization when BCH algorithm is fixed. But in omap-nand case selection of type of BCH algorithm (BCH4 or BCH8) comes from DT binding "ti,nand-ecc-opts". If enabled (CONFIG_BCH_CONST_PARAMS) will optimize lib/bch.c for BCH8 algorithm by default, so CASE: if BCH8 is selected by DT, then no issues CASE: if BCH4 is selected then nand_bch_init() fails with following error + if (!info->nand.ecc.priv) { pr_err("nand: error: unable to use s/w BCH library\n"); err = -EINVAL; goto out_release_mem_region; } [snip] > > if MTD_NAND_OMAP_BCH > > config BCH_CONST_M > > Do you need to to also kill of the Kconfig stuff for BCH_CONST_M and > BCH_CONST_T, which were tied to the MTD_NAND_OMAP_BCH4 and > MTD_NAND_OMAP_BCH8 configs you just removed? > Thanks, good catch. I dint really notice. So, the driver is now updated to separate out two flavours of BCHx scheme. (a) OMAP_ECC_BCHx_CODE_HW: which uses ELM hardware (b) OMAP_ECC_BCHx_CODE_HW_DETECTION_SW: which uses lib/bch.c These BCH_CONST_M and BCH_CONST_T now belongs to (b) family only. - if MTD_NAND_OMAP_BCH + if MTD_NAND_ECC_BCH config BCH_CONST_M (I'll update that).. > > diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c [snip] > > - info->bch = init_bch(nand_chip->ecc.bytes, > > - nand_chip->ecc.strength, > > - OMAP_ECC_BCH8_POLYNOMIAL); > > - if (!info->bch) { > > + info->nand.ecc.priv = nand_bch_init(mtd, > > + info->nand.ecc.size, > > + info->nand.ecc.bytes, > > + &info->nand.ecc.layout); > > Are you sure nand_bch_init() is a proper drop-in replacement for the > implementation you had based on init_bch()? It looks to me like they at > least use a differnt polynomial value (0x201b vs. 0). Is this a problem > for backwards compatibility? > It's not the polynomial value = 0. Rather 0x201b is selected in both cases Refer below code. --------------- When init_bch(m,t, 0) is called from nand_bch_init() then, lib/bch.c @@ init_bch(int m, int t, unsigned int prim_poly) (a) /* default primitive polynomials */ static const unsigned int prim_poly_tab[] = { 0x25, 0x43, 0x83, 0x11d, 0x211, 0x409, 0x805, 0x1053, 0x201b, 0x402b, 0x8003, }; (b) /* select a primitive polynomial for generating GF(2^m) */ if (prim_poly == 0) prim_poly = prim_poly_tab[m-min_m]; (c) And, const int min_m = 5; So, for BCH8 m=13, min_m=5; So prim_poly = prim_poly_tab[13-5] = prim_poly_tab[8] = 0x201b --------------- Hence, there is no change in polynomial, it's just that instead of hard-coding the value, polynomial selection depends on 'm' and 't'. > [...] > > A related question: do we have any current users of this driver that can > provide testing results for this series? Or is this work just tested > with new hardware? > Got a tested-by: jp.francois@cynove.com for BCH4 But that was in May,2013 :-) http://lists.infradead.org/pipermail/linux-mtd/2013-May/047065.html with regards, pekon
2013/10/17 Gupta, Pekon <pekon@ti.com>: >> From: Brian Norris [mailto:computersforpeace@gmail.com] >> > On Tue, Oct 15, 2013 at 11:19:55AM +0530, Pekon Gupta wrote: > [snip] > >> > 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 >> > >> > 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 >> >> Do you know what will happen now if someone configures >> BCH_CONST_PARAMS? >> Would this cause problems? >> > As per comments in lib/bch.c > --------------------------- > * Option CONFIG_BCH_CONST_PARAMS can be used to force fixed values of > * parameters m and t; thus allowing extra compiler optimizations and providing > * better (up to 2x) encoding performance. Using this option makes sense when > * (m,t) are fixed and known in advance, e.g. when using BCH error correction > * on a particular NAND flash device. > --------------------------- > 'BCH_CONST_PARAMS' is required for optimization when BCH algorithm > is fixed. But in omap-nand case selection of type of BCH algorithm > (BCH4 or BCH8) comes from DT binding "ti,nand-ecc-opts". > > If enabled (CONFIG_BCH_CONST_PARAMS) will optimize lib/bch.c > for BCH8 algorithm by default, so > CASE: if BCH8 is selected by DT, then no issues > CASE: if BCH4 is selected then nand_bch_init() fails with following error > + if (!info->nand.ecc.priv) { > pr_err("nand: error: unable to use s/w BCH library\n"); > err = -EINVAL; > goto out_release_mem_region; > } > > [snip] > >> > if MTD_NAND_OMAP_BCH >> > config BCH_CONST_M >> >> Do you need to to also kill of the Kconfig stuff for BCH_CONST_M and >> BCH_CONST_T, which were tied to the MTD_NAND_OMAP_BCH4 and >> MTD_NAND_OMAP_BCH8 configs you just removed? >> > Thanks, good catch. I dint really notice. > So, the driver is now updated to separate out two flavours of BCHx scheme. > (a) OMAP_ECC_BCHx_CODE_HW: which uses ELM hardware > (b) OMAP_ECC_BCHx_CODE_HW_DETECTION_SW: which uses lib/bch.c > These BCH_CONST_M and BCH_CONST_T now belongs to (b) family only. > - if MTD_NAND_OMAP_BCH > + if MTD_NAND_ECC_BCH > config BCH_CONST_M > (I'll update that).. > > >> > diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c > [snip] >> > - info->bch = init_bch(nand_chip->ecc.bytes, >> > - nand_chip->ecc.strength, >> > - OMAP_ECC_BCH8_POLYNOMIAL); >> > - if (!info->bch) { >> > + info->nand.ecc.priv = nand_bch_init(mtd, >> > + info->nand.ecc.size, >> > + info->nand.ecc.bytes, >> > + &info->nand.ecc.layout); >> >> Are you sure nand_bch_init() is a proper drop-in replacement for the >> implementation you had based on init_bch()? It looks to me like they at >> least use a differnt polynomial value (0x201b vs. 0). Is this a problem >> for backwards compatibility? >> > It's not the polynomial value = 0. Rather 0x201b is selected in both cases > Refer below code. > --------------- > When init_bch(m,t, 0) is called from nand_bch_init() then, > lib/bch.c @@ init_bch(int m, int t, unsigned int prim_poly) > (a) /* default primitive polynomials */ > static const unsigned int prim_poly_tab[] = { > 0x25, 0x43, 0x83, 0x11d, 0x211, 0x409, 0x805, 0x1053, 0x201b, > 0x402b, 0x8003, > }; > (b) /* select a primitive polynomial for generating GF(2^m) */ > if (prim_poly == 0) > prim_poly = prim_poly_tab[m-min_m]; > (c) And, const int min_m = 5; > > So, for BCH8 m=13, min_m=5; So > prim_poly = prim_poly_tab[13-5] = prim_poly_tab[8] = 0x201b > --------------- > > Hence, there is no change in polynomial, it's just that instead of > hard-coding the value, polynomial selection depends on 'm' and 't'. > > > >> [...] >> >> A related question: do we have any current users of this driver that can >> provide testing results for this series? Or is this work just tested >> with new hardware? >> > Got a tested-by: jp.francois@cynove.com for BCH4 > But that was in May,2013 :-) > http://lists.infradead.org/pipermail/linux-mtd/2013-May/047065.html > > > with regards, pekon Yes, but I am currently stuck on 3.10, and I need to migrate my out of tree board file to a device tree, and I currently have no bandwidth for this, so I won't be able to test the whole serie, but may be some parts are testable independently ? I will take a look and tell you. Regards, Jean-Philippe François
On Thu, Oct 17, 2013 at 3:14 AM, Gupta, Pekon <pekon@ti.com> wrote: >> From: Brian Norris [mailto:computersforpeace@gmail.com] >> > On Tue, Oct 15, 2013 at 11:19:55AM +0530, Pekon Gupta wrote: > [snip] > >> > 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 >> > >> > 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 >> >> Do you know what will happen now if someone configures >> BCH_CONST_PARAMS? >> Would this cause problems? >> > As per comments in lib/bch.c > --------------------------- > * Option CONFIG_BCH_CONST_PARAMS can be used to force fixed values of > * parameters m and t; thus allowing extra compiler optimizations and providing > * better (up to 2x) encoding performance. Using this option makes sense when > * (m,t) are fixed and known in advance, e.g. when using BCH error correction > * on a particular NAND flash device. > --------------------------- > 'BCH_CONST_PARAMS' is required for optimization when BCH algorithm > is fixed. But in omap-nand case selection of type of BCH algorithm > (BCH4 or BCH8) comes from DT binding "ti,nand-ecc-opts". > > If enabled (CONFIG_BCH_CONST_PARAMS) will optimize lib/bch.c > for BCH8 algorithm by default, so > CASE: if BCH8 is selected by DT, then no issues > CASE: if BCH4 is selected then nand_bch_init() fails with following error > + if (!info->nand.ecc.priv) { > pr_err("nand: error: unable to use s/w BCH library\n"); > err = -EINVAL; > goto out_release_mem_region; > } Ah, so lib/bch.c handles this gracefully enough: #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 >> > diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c > [snip] >> > - info->bch = init_bch(nand_chip->ecc.bytes, >> > - nand_chip->ecc.strength, >> > - OMAP_ECC_BCH8_POLYNOMIAL); >> > - if (!info->bch) { >> > + info->nand.ecc.priv = nand_bch_init(mtd, >> > + info->nand.ecc.size, >> > + info->nand.ecc.bytes, >> > + &info->nand.ecc.layout); >> >> Are you sure nand_bch_init() is a proper drop-in replacement for the >> implementation you had based on init_bch()? It looks to me like they at >> least use a differnt polynomial value (0x201b vs. 0). Is this a problem >> for backwards compatibility? >> > It's not the polynomial value = 0. Rather 0x201b is selected in both cases > Refer below code. > --------------- > When init_bch(m,t, 0) is called from nand_bch_init() then, > lib/bch.c @@ init_bch(int m, int t, unsigned int prim_poly) > (a) /* default primitive polynomials */ > static const unsigned int prim_poly_tab[] = { > 0x25, 0x43, 0x83, 0x11d, 0x211, 0x409, 0x805, 0x1053, 0x201b, > 0x402b, 0x8003, > }; > (b) /* select a primitive polynomial for generating GF(2^m) */ > if (prim_poly == 0) > prim_poly = prim_poly_tab[m-min_m]; > (c) And, const int min_m = 5; > > So, for BCH8 m=13, min_m=5; So > prim_poly = prim_poly_tab[13-5] = prim_poly_tab[8] = 0x201b > --------------- > > Hence, there is no change in polynomial, it's just that instead of > hard-coding the value, polynomial selection depends on 'm' and 't'. I missed that. Thanks for pointing it out. >> [...] >> >> A related question: do we have any current users of this driver that can >> provide testing results for this series? Or is this work just tested >> with new hardware? >> > Got a tested-by: jp.francois@cynove.com for BCH4 > But that was in May,2013 :-) > http://lists.infradead.org/pipermail/linux-mtd/2013-May/047065.html OK, well that's good to know. I suppose the operation of the driver probably hasn't changed a lot in the meantime, just the DT bindings and a few other smaller details. But we still can't call it "Tested-by:" in its current form. Brian
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 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. if MTD_NAND_OMAP_BCH config BCH_CONST_M diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c index 5f6e621..769ff65 100644 --- a/drivers/mtd/nand/omap2.c +++ b/drivers/mtd/nand/omap2.c @@ -25,7 +25,7 @@ #include <linux/of.h> #include <linux/of_device.h> -#include <linux/bch.h> +#include <linux/mtd/nand_bch.h> #include <linux/platform_data/elm.h> #include <linux/platform_data/mtd-nand-omap2.h> @@ -140,7 +140,6 @@ #define BCH_ECC_SIZE1 0x20 /* ecc_size1 = 32 */ #define BADBLOCK_MARKER_LENGTH 2 -#define OMAP_ECC_BCH8_POLYNOMIAL 0x201b #ifdef CONFIG_MTD_NAND_OMAP_BCH static u_char bch8_vector[] = {0xf3, 0xdb, 0x14, 0x16, 0x8b, 0xd2, 0xbe, 0xcc, @@ -173,7 +172,6 @@ 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; @@ -1507,43 +1505,7 @@ static int omap_elm_correct_data(struct mtd_info *mtd, u_char *data, return stat; } -#endif /* CONFIG_MTD_NAND_OMAP_BCH */ -#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 = container_of(mtd, struct omap_nand_info, - mtd); - - count = decode_bch(info->bch, NULL, 512, read_ecc, calc_ecc, NULL, - errloc); - if (count > 0) { - /* correct errors */ - for (i = 0; i < count; i++) { - /* correct data only, not ecc bytes */ - if (errloc[i] < 8*512) - data[errloc[i]/8] ^= 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 page * @mtd: mtd info structure @@ -1660,28 +1622,6 @@ static int is_elm_present(struct omap_nand_info *info, } #endif /* CONFIG_MTD_NAND_ECC_BCH */ -#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 = container_of(mtd, struct omap_nand_info, - mtd); - if (info->bch) { - free_bch(info->bch); - info->bch = 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; @@ -1714,13 +1654,13 @@ static int omap_nand_probe(struct platform_device *pdev) info->pdev = pdev; info->gpmc_cs = pdata->cs; info->reg = pdata->reg; - info->bch = NULL; info->of_node = pdata->of_node; mtd = &info->mtd; mtd->priv = &info->nand; mtd->name = dev_name(&pdev->dev); mtd->owner = THIS_MODULE; nand_chip = &info->nand; + nand_chip->ecc.priv = NULL; nand_chip->options |= NAND_SKIP_BBTSCAN | NAND_BUSWIDTH_AUTO; res = platform_get_resource(pdev, IORESOURCE_MEM, 0); @@ -1910,7 +1850,7 @@ static int omap_nand_probe(struct platform_device *pdev) nand_chip->ecc.bytes = 7; nand_chip->ecc.strength = 4; nand_chip->ecc.hwctl = omap3_enable_hwecc_bch; - nand_chip->ecc.correct = omap3_correct_data_bch; + info->nand.ecc.correct = nand_bch_correct_data; nand_chip->ecc.calculate = omap3_calculate_ecc_bch4; /* define ECC layout */ ecclayout->eccbytes = nand_chip->ecc.bytes * @@ -1920,10 +1860,11 @@ static int omap_nand_probe(struct platform_device *pdev) ecclayout->oobfree->offset = ecclayout->eccpos[0] + ecclayout->eccbytes; /* software bch library is used for locating errors */ - info->bch = init_bch(nand_chip->ecc.bytes, - nand_chip->ecc.strength, - OMAP_ECC_BCH8_POLYNOMIAL); - if (!info->bch) { + info->nand.ecc.priv = 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 = -EINVAL; } @@ -1975,7 +1916,7 @@ static int omap_nand_probe(struct platform_device *pdev) nand_chip->ecc.bytes = 13; nand_chip->ecc.strength = 8; nand_chip->ecc.hwctl = omap3_enable_hwecc_bch; - nand_chip->ecc.correct = omap3_correct_data_bch; + info->nand.ecc.correct = nand_bch_correct_data; nand_chip->ecc.calculate = omap3_calculate_ecc_bch8; /* define ECC layout */ ecclayout->eccbytes = nand_chip->ecc.bytes * @@ -1985,10 +1926,11 @@ static int omap_nand_probe(struct platform_device *pdev) ecclayout->oobfree->offset = ecclayout->eccpos[0] + ecclayout->eccbytes; /* software bch library is used for locating errors */ - info->bch = init_bch(nand_chip->ecc.bytes, - nand_chip->ecc.strength, - OMAP_ECC_BCH8_POLYNOMIAL); - if (!info->bch) { + info->nand.ecc.priv = 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 = -EINVAL; goto out_release_mem_region; @@ -2074,7 +2016,10 @@ 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(mtd); + if (info->nand.ecc.priv) { + nand_bch_free(info->nand.ecc.priv); + info->nand.ecc.priv = NULL; + } kfree(info); return err; @@ -2086,7 +2031,10 @@ static int omap_nand_remove(struct platform_device *pdev) struct nand_chip *nand_chip = mtd->priv; struct omap_nand_info *info = container_of(mtd, struct omap_nand_info, mtd); - omap3_free_bch(mtd); + if (info->nand.ecc.priv) { + nand_bch_free(info->nand.ecc.priv); + info->nand.ecc.priv = NULL; + } if (info->dma) dma_release_channel(info->dma);
generic frame-work in mtd/nand/nand_bch.c is a wrapper above lib/bch.h which encapsulates all control information specific to BCH ecc algorithm in software. Thus this patch: (1) replace omap specific implementations with equivalent wrapper in nand_bch.c so that more generic code is re-used. like; omap3_correct_data_bch() -> nand_bch_correct_data() omap3_free_bch() -> nand_bch_free() (2) replace direct calls to lib/bch.c with wrapper functions defined in nand_bch.c init_bch() -> nand_bch_init() (3) removes selection between BCH8 and BCH4 h/w ecc-schemes via KConfig. This selection is now based on ti,nand-ecc-opt and ti,elm-id DT bindings. Signed-off-by: Pekon Gupta <pekon@ti.com> --- drivers/mtd/nand/Kconfig | 30 ++------------- drivers/mtd/nand/omap2.c | 96 +++++++++++------------------------------------- 2 files changed, 26 insertions(+), 100 deletions(-)