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Date:   Thu, 24 Aug 2017 11:19:56 +0200
From:   Andrea Adami <andrea.adami@...il.com>
To:     Boris Brezillon <boris.brezillon@...e-electrons.com>
Cc:     linux-mtd@...ts.infradead.org,
        David Woodhouse <dwmw2@...radead.org>,
        Brian Norris <computersforpeace@...il.com>,
        Marek Vasut <marek.vasut@...il.com>,
        Richard Weinberger <richard@....at>,
        Cyrille Pitchen <cyrille.pitchen@...ev4u.fr>,
        Rafał Miłecki <rafal@...ecki.pl>,
        Haojian Zhuang <haojian.zhuang@...il.com>,
        Dmitry Eremin-Solenikov <dbaryshkov@...il.com>,
        Robert Jarzmik <robert.jarzmik@...e.fr>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v6] mtd: sharpslpart: Add sharpslpart partition parser

Boris,

thanks for the review.
I have made the required changes apart th elast one: error values to
be returned..
Please see my comments.

On Tue, Aug 22, 2017 at 2:54 PM, Boris Brezillon
<boris.brezillon@...e-electrons.com> wrote:
> Hi Andrea,
>
> Le Tue, 22 Aug 2017 11:42:52 +0200,
> Andrea Adami <andrea.adami@...il.com> a écrit :
>
>> The Sharp SL Series (Zaurus) PXA handhelds have 16/64/128M of NAND flash
>> and share the same layout of the first 7M partition, managed by Sharp FTL.
>>
>> The purpose of this self-contained patch is to add a common parser and
>> remove the hardcoded sizes in the board files (these devices are not yet
>> converted to devicetree).
>> Users will have benefits because the mtdparts= tag will not be necessary
>> anymore and they will be free to repartition the little sized flash.
>>
>> The obsolete bootloader can not pass the partitioning info to modern
>> kernels anymore so it has to be read from flash at known logical addresses.
>> (see http://www.h5.dion.ne.jp/~rimemoon/zaurus/memo_006.htm )
>>
>> In kernel, under arch/arm/mach-pxa we have already 8 machines:
>> MACH_POODLE, MACH_CORGI, MACH_SHEPERD, MACH_HUSKY, MACH_AKITA, MACH_SPITZ,
>> MACH_BORZOI, MACH_TOSA.
>> Lost after the 2.4 vendor kernel are MACH_BOXER and MACH_TERRIER.
>>
>> Almost every model has different factory partitioning: add to this the
>> units can be repartitioned by users with userspace tools (nandlogical)
>> and installers for popular (back then) linux distributions.
>>
>> The Parameter Area in the first (boot) partition extends from 0x00040000 to
>> 0x0007bfff (176k) and contains two copies of the partition table:
>> ...
>> 0x00060000: Partition Info1     16k
>> 0x00064000: Partition Info2     16k
>> 0x00668000: Model               16k
>> ...
>>
>> The first 7M partition is managed by the Sharp FTL reserving 5% + 1 blocks
>> for wear-leveling: some blocks are remapped and one layer of translation
>> (logical to physical) is necessary.
>>
>> There isn't much documentation about this FTL in the 2.4 sources, just the
>> MTD methods for reading and writing using logical addresses and the block
>> management (wear-leveling, use counter).
>> For the purpose of the MTD parser only the read part of the code was taken.
>>
>> The NAND drivers that can use this parser are sharpsl.c and tmio_nand.c.
>>
>> Signed-off-by: Andrea Adami <andrea.adami@...il.com>
>> ---
>
> Please put a changelog here.
Sure, I'll take the one from the cover-letter.

>
>>  drivers/mtd/parsers/Kconfig       |   7 +
>>  drivers/mtd/parsers/Makefile      |   1 +
>>  drivers/mtd/parsers/sharpslpart.c | 382 ++++++++++++++++++++++++++++++++++++++
>>  3 files changed, 390 insertions(+)
>>  create mode 100644 drivers/mtd/parsers/sharpslpart.c
>>
>> diff --git a/drivers/mtd/parsers/Kconfig b/drivers/mtd/parsers/Kconfig
>> index d206b3c..f371022 100644
>> --- a/drivers/mtd/parsers/Kconfig
>> +++ b/drivers/mtd/parsers/Kconfig
>> @@ -6,3 +6,10 @@ config MTD_PARSER_TRX
>>         may contain up to 3/4 partitions (depending on the version).
>>         This driver will parse TRX header and report at least two partitions:
>>         kernel and rootfs.
>
> Missing blank line.
Fixed

>
>> +config MTD_SHARPSL_PARTS
>> +     tristate "Sharp SL Series NAND flash partition parser"
>> +     depends on MTD_NAND_SHARPSL || MTD_NAND_TMIO || COMPILE_TEST
>> +     help
>> +       This provides the read-only FTL logic necessary to read the partition
>> +       table from the NAND flash of Sharp SL Series (Zaurus) and the MTD
>> +       partition parser using this code.
>> diff --git a/drivers/mtd/parsers/Makefile b/drivers/mtd/parsers/Makefile
>> index 4d9024e..5b1bcc3 100644
>> --- a/drivers/mtd/parsers/Makefile
>> +++ b/drivers/mtd/parsers/Makefile
>> @@ -1 +1,2 @@
>>  obj-$(CONFIG_MTD_PARSER_TRX)         += parser_trx.o
>> +obj-$(CONFIG_MTD_SHARPSL_PARTS)              += sharpslpart.o
>> diff --git a/drivers/mtd/parsers/sharpslpart.c b/drivers/mtd/parsers/sharpslpart.c
>> new file mode 100644
>> index 0000000..b2333ae
>> --- /dev/null
>> +++ b/drivers/mtd/parsers/sharpslpart.c
>> @@ -0,0 +1,382 @@
>> +/*
>> + * sharpslpart.c - MTD partition parser for NAND flash using the SHARP FTL
>> + * for logical addressing, as used on the PXA models of the SHARP SL Series.
>> + *
>> + * Copyright (C) 2017 Andrea Adami <andrea.adami@...il.com>
>> + *
>> + * Based on 2.4 sources:
>> + *  drivers/mtd/nand/sharp_sl_logical.c
>> + *  linux/include/asm-arm/sharp_nand_logical.h
>> + *
>> + * Copyright (C) 2002 SHARP
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License as published by
>> + * the Free Software Foundation; either version 2 of the License, or
>> + * (at your option) any later version.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> + * GNU General Public License for more details.
>> + *
>> + */
>> +
>> +#include <linux/kernel.h>
>> +#include <linux/slab.h>
>> +#include <linux/module.h>
>> +#include <linux/types.h>
>> +#include <linux/mtd/mtd.h>
>> +#include <linux/mtd/partitions.h>
>> +
>> +/* oob structure */
>> +#define NAND_NOOB_LOGADDR_00         8
>> +#define NAND_NOOB_LOGADDR_01         9
>> +#define NAND_NOOB_LOGADDR_10         10
>> +#define NAND_NOOB_LOGADDR_11         11
>> +#define NAND_NOOB_LOGADDR_20         12
>> +#define NAND_NOOB_LOGADDR_21         13
>> +
>> +#define BLOCK_IS_RESERVED            0xffff
>> +#define BLOCK_UNMASK                 0x07fe
>> +#define BLOCK_UNMASK_COMPLEMENT              1
>> +
>> +/* factory defaults */
>> +#define SHARPSL_NAND_PARTS           3
>> +#define SHARPSL_FTL_PART_SIZE                (7 * 1024 * 1024)
>
> Nit: s/7 * 1024 * 1024/7 * SZ_1M/
Fixed

>
>> +#define PARAM_BLOCK_PARTITIONINFO1   0x00060000
>> +#define PARAM_BLOCK_PARTITIONINFO2   0x00064000
>
> I'd rename the macro differently. The term block is a bit confusing
> here since AFAIU the Param Area does not necessarily fit in a single
> eraseblock.
>
> How about:
>
> #define PARAM_AREA_PARTINFO1_LADDR      0x60000
> #define PARAM_AREA_PARTINFO2_LADDR      0x64000
>
> or simply
>
> #define SHARPSL_PARTINFO1_LADDR         0x60000
> #define SHARPSL_PARTINFO2_LADDR         0x64000
Used these, nicer

>
>> +
>> +#define BOOT_MAGIC                   0x424f4f54
>> +#define FSRO_MAGIC                   0x4653524f
>> +#define FSRW_MAGIC                   0x46535257
>> +
>> +/**
>> + * struct sharpsl_ftl - Sharp FTL Logical Table
>> + * @logmax:          number of logical blocks
>> + * @log2phy:         the logical-to-physical table
>> + *
>> + * Stripped down from 2.4 sources for read-only purposes.
>
> Not sure this information is really useful, especially since you don't
> provide a link to the 2.4 sources (or maybe I missed it).

Maybe here I can add that this FTL was originally tailored for devices
16KiB erasesize matching the size of the PARAM_BLOCK_ above thus using
two separate blocks for the partition tables. Should I add an
ASCII-art? Pls see
http://www.h5.dion.ne.jp/~rimemoon/zaurus/memo_006.htm
BTW the link was in the cover-letter 0/9, I'll put it here together
with the changelog.

>
> You'd better describe what this struct is used for here.
Seems self-explanatory..2 fields commented. What would you add here?

>
>> + */
>> +struct sharpsl_ftl {
>> +     u_int logmax;
>> +     u_int *log2phy;
>
> Can you replace u_int by unsigned int and u_char by u8? That goes for
> the whole file.
Yes, done

>
>> +};
>> +
>> +static int sharpsl_nand_read_oob(struct mtd_info *mtd, loff_t offs, size_t len,
>
> AFAICT, len is always set to mtd->oobsize. You can just drop this
> parameter and set ops->ooblen to mtd->oobsize.
>
>> +                              uint8_t *buf)
>> +{
>> +     loff_t mask = mtd->writesize - 1;
>
> mask is equivalent to mtd->writesize_mask.
>
>> +     struct mtd_oob_ops ops;
>
>         struct mtd_oob_ops ops = { };
>
> so that you don't have to initialize all fields if they are set to 0 or
> NULL.
>
Ok done, I prefer this syntax, like in the other ftl using read_oob().

> You could also directly fill this object when declaring it:
>
>         struct mtd_oob_ops ops = {
>                 .mode = MTD_OPS_PLACE_OOB,
>                 .ooblen = mtd->oobsize,
>                 .oobbuf = buf,
>         };
>
>> +     int ret;
>> +
>> +     ops.mode = MTD_OPS_PLACE_OOB;
>> +     ops.ooboffs = offs & mask;
>
> Hm, I'm pretty sure this is wrong. mask is a page mask, not the oob
> area mask. It works because offs is always aligned on a page, but you
> can directly assign ops.ooboffs to 0 and you should be good.
>
You are right, I removed the mask alltogether.

>> +     ops.ooblen = len;
>> +     ops.oobbuf = buf;
>> +     ops.datbuf = NULL;
>> +
>> +     ret = mtd_read_oob(mtd, offs & ~mask, &ops);
>> +     if (ret != 0 || len != ops.oobretlen)
>> +             return -1;
>> +
>> +     return 0;
>> +}
>> +
>> +/*
>> + * The logical block number assigned to a physical block is stored in the OOB
>> + * of the first page, in 3 16-bit copies with the following layout:
>> + *
>> + * 01234567 89abcdef
>> + * -------- --------
>> + * ECC BB   xyxyxy
>> + *
>> + * When reading we check that the first two copies agree.
>> + * In case of error, matching is tried using the following pairs.
>> + * Reserved values 0xffff mean the block is kept for wear leveling.
>> + *
>> + * 01234567 89abcdef
>> + * -------- --------
>> + * ECC BB   xyxy    oob[8]==oob[10] && oob[9]==oob[11]   -> byte0=8   byte1=9
>> + * ECC BB     xyxy  oob[10]==oob[12] && oob[11]==oob[13] -> byte0=10  byte1=11
>> + * ECC BB   xy  xy  oob[12]==oob[8] && oob[13]==oob[9]   -> byte0=12  byte1=13
>> + *
>> + */
>> +static u_int sharpsl_nand_get_logical_num(u_char *oob)
>> +{
>> +     u16 us;
>> +     int good0, good1;
>> +
>> +     if (oob[NAND_NOOB_LOGADDR_00] == oob[NAND_NOOB_LOGADDR_10] &&
>> +         oob[NAND_NOOB_LOGADDR_01] == oob[NAND_NOOB_LOGADDR_11]) {
>> +             good0 = NAND_NOOB_LOGADDR_00;
>> +             good1 = NAND_NOOB_LOGADDR_01;
>> +     } else if (oob[NAND_NOOB_LOGADDR_10] == oob[NAND_NOOB_LOGADDR_20] &&
>> +                oob[NAND_NOOB_LOGADDR_11] == oob[NAND_NOOB_LOGADDR_21]) {
>> +             good0 = NAND_NOOB_LOGADDR_10;
>> +             good1 = NAND_NOOB_LOGADDR_11;
>> +     } else if (oob[NAND_NOOB_LOGADDR_20] == oob[NAND_NOOB_LOGADDR_00] &&
>> +                oob[NAND_NOOB_LOGADDR_21] == oob[NAND_NOOB_LOGADDR_01]) {
>> +             good0 = NAND_NOOB_LOGADDR_20;
>> +             good1 = NAND_NOOB_LOGADDR_21;
>> +     } else {
>> +             /* wrong oob fingerprint, maybe here by mistake? */
>> +             return UINT_MAX;
>> +     }
>> +
>> +     us = oob[good0] | oob[good1] << 8;
>> +
>> +     /* parity check */
>> +     if (hweight16(us) & BLOCK_UNMASK_COMPLEMENT)
>> +             return (UINT_MAX - 1);
>
> Why not making this function return an int and use regular error codes
> for the parity and wrong fingerprint errors?
>
Originally in case of error it did return the largest values.
I can return a negative int but then I'd have to check for log_no >0

Besides, what are the 'regular' error codes you'd use here?
For the missing FTL we do return -EINVAL later so I'd say this is the
error for the wrong oob fingerprint.

About the parity error, it does return UINT_MAX -1 so to allow very
large log_num. This value is always bigger than log_max so it is
skipped in the actual code but the read continues.
Should we change the philosophy of the old 2.4 code and exit in case
of parity errors?

>> +
>> +     /* reserved */
>> +     if (us == BLOCK_IS_RESERVED)
>> +             return BLOCK_IS_RESERVED;
>> +     else
>
> You can drop the 'else' here.
Done
>
>> +             return (us & BLOCK_UNMASK) >> 1;
>
> So, this is a 10bit value, right? Why not doing the >> 1 first so that
> your BLOCK_UNMASK mask really looks like a valid mask (0x3ff, which can
> also be defined as GENMASK(9, 0)).
Right, very nice. Done.
Can I keep BLOCK_UNMASK COMPLEMENT = 1 ?

>
>> +}
>> +
>> +static int sharpsl_nand_init_logical(struct mtd_info *mtd, u32 partition_size,
>
> s/sharpsl_nand_init_logical/sharpsl_nand_init_ftl/
Oh yes, renamed

>
> partition_size is always set to SHARPSL_FTL_PART_SIZE. Please drop this
> argument.
>
Ok, done

>> +                                  struct sharpsl_ftl *ftl)
>> +{
>> +     u_int block_num, log_num, phymax;
>> +     loff_t block_adr;
>> +     u_char *oob;
>> +     int i, ret;
>> +
>> +     oob = kzalloc(mtd->oobsize, GFP_KERNEL);
>> +     if (!oob)
>> +             return -ENOMEM;
>> +
>> +     /* initialize management structure */
>> +     phymax = (partition_size / mtd->erasesize);
>
> You can use mtd_div_by_eb() here.
>
Done for all occurrences

>> +
>> +     /* FTL reserves 5% of the blocks + 1 spare  */
>> +     ftl->logmax = ((phymax * 95) / 100) - 1;
>> +
>> +     ftl->log2phy = kmalloc_array(ftl->logmax, sizeof(u_int),
>
>                                                   sizeof(*ftl->log2phy)
Ok, changed.

>
>> +                                  GFP_KERNEL);
>> +     if (!ftl->log2phy) {
>> +             ret = -ENOMEM;
>> +             goto exit;
>> +     }
>> +
>> +     /* initialize ftl->log2phy */
>> +     for (i = 0; i < ftl->logmax; i++)
>> +             ftl->log2phy[i] = UINT_MAX;
>> +
>> +     /* create physical-logical table */
>> +     for (block_num = 0; block_num < phymax; block_num++) {
>> +             block_adr = block_num * mtd->erasesize;
>> +
>> +             if (mtd_block_isbad(mtd, block_adr))
>> +                     continue;
>> +
>> +             if (sharpsl_nand_read_oob(mtd, block_adr, mtd->oobsize, oob))
>> +                     continue;
>> +
>> +             /* get logical block */
>> +             log_num = sharpsl_nand_get_logical_num(oob);
>> +
>> +             /* FTL is not used? Exit here if the oob fingerprint is wrong */
>> +             if (log_num == UINT_MAX) {
>> +                     pr_info("sharpslpart: Sharp SL FTL not found.\n");
>> +                     ret = -EINVAL;
>> +                     goto exit;
>> +             }
>> +
>> +             /* skip out of range and not unique values */
>> +             if (log_num < ftl->logmax) {
>> +                     if (ftl->log2phy[log_num] == UINT_MAX)
>> +                             ftl->log2phy[log_num] = block_num;
>> +             }
>> +     }
>> +
>> +     pr_info("Sharp SL FTL: %d blocks used (%d logical, %d reserved)\n",
>> +             phymax, ftl->logmax,
>> +             phymax - ftl->logmax);
>> +
>> +     ret = 0;
>> +exit:
>> +     kfree(oob);
>> +     return ret;
>> +}
>> +
>> +void sharpsl_nand_cleanup_logical(struct sharpsl_ftl *ftl)
>
> s/sharpsl_nand_cleanup_logical/sharpsl_nand_cleanup_ftl/
>
Yes, renamed as well

>> +{
>> +     kfree(ftl->log2phy);
>> +}
>> +
>> +static int sharpsl_nand_read_laddr(struct mtd_info *mtd,
>> +                                loff_t from,
>> +                                size_t len,
>> +                                u_char *buf,
>> +                                struct sharpsl_ftl *ftl)
>> +{
>> +     u_int log_num, log_new;
>> +     u_int block_num;
>> +     loff_t block_adr;
>> +     loff_t block_ofs;
>> +     size_t retlen;
>> +     int err;
>> +
>> +     log_num = (u32)from / mtd->erasesize;
>
> Please use mtd_div_by_eb().
>
>> +     log_new = ((u32)from + len - 1) / mtd->erasesize;
>
> Ditto.
>
> And I'm not sure log_new is a good name for this variable. Could be
> last_log_num or something like that.
>
>> +
>> +     if (len <= 0 || log_num >= ftl->logmax || log_new > log_num)
>> +             return -EINVAL;
>> +
>> +     block_num = ftl->log2phy[log_num];
>> +     block_adr = block_num * mtd->erasesize;
>> +     block_ofs = (u32)from % mtd->erasesize;
>
> mtd_mod_by_eb().
>
>> +
>> +     err = mtd_read(mtd, block_adr + block_ofs, len, &retlen, buf);
>> +     /* Ignore corrected ECC errors */
>> +     if (mtd_is_bitflip(err))
>> +             err = 0;
>
> Please add a blank line here
>
Ok

>> +     if (!err && retlen != len)
>> +             err = -EIO;
>
> and here.
>
Ok (was taken from mtdtest_read()  fwiw)

>> +     if (err)
>> +             pr_err("sharpslpart: error, read failed at %#llx\n",
>> +                    block_adr + block_ofs);
>> +
>> +     return err;
>> +}
>> +
>> +/*
>> + * MTD Partition Parser
>> + *
>> + * Sample values read from SL-C860
>> + *
>> + * # cat /proc/mtd
>> + * dev:    size   erasesize  name
>> + * mtd0: 006d0000 00020000 "Filesystem"
>> + * mtd1: 00700000 00004000 "smf"
>> + * mtd2: 03500000 00004000 "root"
>> + * mtd3: 04400000 00004000 "home"
>> + *
>> + * PARTITIONINFO1
>> + * 0x00060000: 00 00 00 00 00 00 70 00 42 4f 4f 54 00 00 00 00  ......p.BOOT....
>> + * 0x00060010: 00 00 70 00 00 00 c0 03 46 53 52 4f 00 00 00 00  ..p.....FSRO....
>> + * 0x00060020: 00 00 c0 03 00 00 00 04 46 53 52 57 00 00 00 00  ........FSRW....
>> + * 0x00060030: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff  ................
>> + *
>
> You can drop this extra empty line.
Ok

>
>> + */
>> +struct sharpsl_nand_partinfo {
>> +     __le32 start;
>> +     __le32 end;
>> +     __be32 magic;
>> +     u32 reserved;
>> +};
>> +
>> +static int sharpsl_nand_read_partinfo(struct mtd_info *master,
>> +                                   loff_t from,
>> +                                   size_t len,
>> +                                   struct sharpsl_nand_partinfo *buf,
>> +                                   struct sharpsl_ftl *ftl)
>> +{
>> +     int ret;
>> +
>> +     ret = sharpsl_nand_read_laddr(master, (u32)from, len, (u_char *)buf,
>
> The u32 cast is unneeded here, and I'd suggest to change the
> sharpsl_nand_read_laddr() prototype to take a 'void *' instead of a
> 'u_char *', so that you can also get rid of this cast.
>
Nice, done

>> +                                   ftl);
>> +     if (ret)
>> +             goto exit;
>
> Well, you have nothing to cleanup in the exit path, so you can return
> directly here.
>
Ah, I have exaggerated here :)  Done all three

>> +
>> +     /* check for magics */
>> +     if (be32_to_cpu(buf[0].magic) != BOOT_MAGIC ||
>> +         be32_to_cpu(buf[1].magic) != FSRO_MAGIC ||
>> +         be32_to_cpu(buf[2].magic) != FSRW_MAGIC) {
>> +             pr_err("sharpslpart: magic values mismatch\n");
>> +             ret = -EINVAL;
>> +             goto exit;
>
> Ditto.
>
>> +     }
>> +
>> +     /* fixup for hardcoded value 64 MiB (for older models) */
>> +     buf[2].end = cpu_to_le32(master->size);
>> +
>> +     /* extra sanity check */
>> +     if (le32_to_cpu(buf[0].end) <= le32_to_cpu(buf[0].start) ||
>> +         le32_to_cpu(buf[1].start) < le32_to_cpu(buf[0].end) ||
>> +         le32_to_cpu(buf[1].end) <= le32_to_cpu(buf[1].start) ||
>> +         le32_to_cpu(buf[2].start) < le32_to_cpu(buf[1].end) ||
>> +         le32_to_cpu(buf[2].end) <= le32_to_cpu(buf[2].start)) {
>> +             pr_err("sharpslpart: partition sizes mismatch\n");
>> +             ret = -EINVAL;
>> +             goto exit;
>
> Ditto.
>
>> +     }
>> +
>> +     ret = 0;
>> +exit:
>> +     return ret;
>> +}
>> +
>> +static int sharpsl_parse_mtd_partitions(struct mtd_info *master,
>> +                                     const struct mtd_partition **pparts,
>> +                                     struct mtd_part_parser_data *data)
>> +{
>> +     struct sharpsl_ftl ftl;
>> +     struct sharpsl_nand_partinfo buf[SHARPSL_NAND_PARTS];
>> +     struct mtd_partition *sharpsl_nand_parts;
>> +     int err, ret;
>> +
>> +     /* init logical mgmt (FTL) */
>> +     err = sharpsl_nand_init_logical(master, SHARPSL_FTL_PART_SIZE, &ftl);
>> +     if (err)
>> +             return err;
>> +
>> +     /* read and validate first partition table */
>> +     pr_info("sharpslpart: using first partition table\n");
>> +     err = sharpsl_nand_read_partinfo(master,
>> +                                      PARAM_BLOCK_PARTITIONINFO1,
>> +                                      sizeof(buf), buf, &ftl);
>> +     if (err) {
>> +             /* fallback: read second partition table */
>> +             pr_warn("sharpslpart: retry using second partition table\n");
>> +             ret = sharpsl_nand_read_partinfo(master,
>> +                                              PARAM_BLOCK_PARTITIONINFO2,
>> +                                              sizeof(buf), buf, &ftl);
>
> Why do you need a different variable to store the second
> sharpsl_nand_read_partinfo() return code?
>
It is unneeded, is a copy&paste remnant. Fixed.

>> +             if (ret) {
>> +                     pr_err("sharpslpart: partition tables are invalid\n");
>> +                     sharpsl_nand_cleanup_logical(&ftl);
>> +                     return ret;
>> +             }
>> +     }
>> +
>> +     /* cleanup logical mgmt (FTL) */
>> +     sharpsl_nand_cleanup_logical(&ftl);
>
>
> How about:
>
>         pr_info("sharpslpart: try reading first partition table\n");
>         err = sharpsl_nand_read_partinfo(master,
>                                          PARAM_BLOCK_PARTITIONINFO1,
>                                          sizeof(buf), buf, &ftl);
>         if (err) {
>                 /* fallback: read second partition table */
>                 pr_warn("sharpslpart: first partition table is invalid, retry using second partition table\n");
>                 err = sharpsl_nand_read_partinfo(master,
>                                                  PARAM_BLOCK_PARTITIONINFO2,
>                                                  sizeof(buf), buf, &ftl);
>         }
>
>         /* cleanup logical mgmt (FTL) */
>         sharpsl_nand_cleanup_logical(&ftl);
>
>         if (err) {
>                 pr_err("sharpslpart: both partition tables are invalid\n");
>                 return ret;
>         }
>
> so that you have a single place where you cleanup the FTL.
Very nice. I was mumbling around it...
Done

>
>> +
>> +     sharpsl_nand_parts = kzalloc(sizeof(*sharpsl_nand_parts) *
>> +                                  SHARPSL_NAND_PARTS, GFP_KERNEL);
>> +     if (!sharpsl_nand_parts)
>> +             return -ENOMEM;
>> +
>> +     /* original names */
>> +     sharpsl_nand_parts[0].name = "smf";
>> +     sharpsl_nand_parts[0].offset = le32_to_cpu(buf[0].start);
>> +     sharpsl_nand_parts[0].size = le32_to_cpu(buf[0].end) -
>> +                                  le32_to_cpu(buf[0].start);
>> +
>> +     sharpsl_nand_parts[1].name = "root";
>> +     sharpsl_nand_parts[1].offset = le32_to_cpu(buf[1].start);
>> +     sharpsl_nand_parts[1].size = le32_to_cpu(buf[1].end) -
>> +                                  le32_to_cpu(buf[1].start);
>> +
>> +     sharpsl_nand_parts[2].name = "home";
>> +     sharpsl_nand_parts[2].offset = le32_to_cpu(buf[2].start);
>> +     sharpsl_nand_parts[2].size = le32_to_cpu(buf[2].end) -
>> +                                  le32_to_cpu(buf[2].start);
>> +
>> +     *pparts = sharpsl_nand_parts;
>> +     return SHARPSL_NAND_PARTS;
>> +}
>> +
>> +static struct mtd_part_parser sharpsl_mtd_parser = {
>> +     .parse_fn = sharpsl_parse_mtd_partitions,
>> +     .name = "sharpslpart",
>> +};
>> +module_mtd_part_parser(sharpsl_mtd_parser);
>> +
>> +MODULE_LICENSE("GPL");
>> +MODULE_AUTHOR("Andrea Adami <andrea.adami@...il.com>");
>> +MODULE_DESCRIPTION("MTD partitioning for NAND flash on Sharp SL Series");
>
Thank you very much. Code is getting better and better.
Andrea

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