On 06/16/2017 02:40 PM, Cyrille Pitchen wrote:
> From: Cyrille Pitchen <cyrille.pitc...@atmel.com>
> 
> This patch adds support to the JESD216B standard and parses the SFDP
> tables to dynamically initialize the 'struct spi_nor_flash_parameter'.
> 
> Signed-off-by: Cyrille Pitchen <cyrille.pitc...@atmel.com>
> ---
> Hi all,
> 
> starting a new series since most patches of previous series have already
> been merged into the spi-nor/next branch of l2-mtd, hence also available
> in linux-next (support of the 4-byte address instruction set and SPI 1-4-4
> protocol).
> So this is the continuation of my work:
> https://patchwork.ozlabs.org/patch/742380/
> 
> From v5 RFC, I've made the following changes (taking Marek's comments
> into account):
> - rebase the SFDP patch so it no longer depends on the patch adding
>   support of SPI NOR memories with non-uniform erase sector map. I'm still
>   working on this other topic too, studying Marek's suggestions on how to
>   manage the erase sector maps, but this is not ready yet.
>   So I'm focusing on SFDP first. Anyway, the actual layout of the erase
>   sector map is provided by some dedicated SFDP table, the Sector Map table.
> 
> - rewrite the final test at the end of spansion_new_quad_enable() and
>   sr2_bit7_quad_enable() so it follows a common pattern with the already
>   existing macronix_quad_enable() and spansion_quad_enable() functions.
> 
> - remove some u32 and u16 casts.
> 
> - replace the 'enum sfdp_bfpt_dword' by a DFPT_DWORD() macro so we can
>   handle the translation from 1-indexed JESD216 Basic Flash Parameter
>   DWORDx and the 0-indexed arrays of the C language.
> 
> - remove some u in integral constants: 0x07u -> 0x07
> 
> - remove dev_err() message when kmalloc() fails
> 
> - test return code of spi_nor_parse_sfdp() from spi_nor_init_params().
> 
> - fix the decoding of the SPI NOR flash memory size from DWORD2 of the
>   Basic Flash Paramaters: a +1 was missing to get the correct size.
> 
> - add check of DWORD1 to handle the cases of 3-byte only and 4-byte only
>   address.
> 
> - restore the 'struct spi_nor_flash_parameter' to its previous state if
>   the parsing of the SFDP tables fails for any reason.
> 
> - add a new test to skip the parsing of the SFDP tables: since all 'old'
>   SPI memories are not JESD216x compliant (this specification did not exit
>   yet), we try to parse the SFDP tables only for memory with info->flags
>   including SPI_NOR_DUAL_READ or SPI_NOR_QUAD_READ. Indeed, SFDP tables
>   are mainly used to get settings of Dual and/or Quad SPI commands.
>   Also, AFAIK, SPI NOR memories compliant with the JESD216x specification
>   are all QSPI memories.
>   Avoiding sending a useless command to 'old' SPI NOR memories prevents
>   from slowing the detection of the memory and maybe (never get this case
>   yet) from getting unexpected side effects.
> 
> 
> Best regards,
> 
> Cyrille
> 
> 
>  drivers/mtd/spi-nor/spi-nor.c | 590 
> +++++++++++++++++++++++++++++++++++++++++-
>  include/linux/mtd/spi-nor.h   |   6 +
>  2 files changed, 594 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
> index eef55b597ec7..dcac6d2d8651 100644
> --- a/drivers/mtd/spi-nor/spi-nor.c
> +++ b/drivers/mtd/spi-nor/spi-nor.c
> @@ -17,6 +17,7 @@
>  #include <linux/mutex.h>
>  #include <linux/math64.h>
>  #include <linux/sizes.h>
> +#include <linux/slab.h>
>  
>  #include <linux/mtd/mtd.h>
>  #include <linux/of_platform.h>
> @@ -86,6 +87,7 @@ struct flash_info {
>                                        * to support memory size above 128Mib.
>                                        */
>  #define NO_CHIP_ERASE                BIT(12) /* Chip does not support chip 
> erase */
> +#define SPI_NOR_SKIP_SFDP    BIT(13) /* Skip parsing of SFDP tables */
>  };
>  
>  #define JEDEC_MFR(info)      ((info)->id[0])
> @@ -1447,6 +1449,97 @@ static int spansion_quad_enable(struct spi_nor *nor)
>       return 0;
>  }

Please add kerneldoc , also I dunno about the _new_ name , maybe you
should find something more descriptive. The _new_ will be obsolete once
spansion invents something newer .

> +static int spansion_new_quad_enable(struct spi_nor *nor)
> +{
> +     u8 sr_cr[2];
> +     int ret;
> +
> +     /* Check current Quad Enable bit value. */
> +     ret = read_cr(nor);
> +     if (ret < 0) {
> +             dev_err(nor->dev,
> +                     "error while reading configuration register\n");
> +             return -EINVAL;
> +     }
> +     sr_cr[1] = ret;
> +     if (sr_cr[1] & CR_QUAD_EN_SPAN)
> +             return 0;

I'd invert this, so that the code would test the rest and only then
assign it into sr_cr, ie.

if (ret & CR_....)
  return 0;

sr_cr[1] = ret;

> +     /* Keep the current value of the Status Register. */
> +     ret = read_sr(nor);
> +     if (ret < 0) {
> +             dev_err(nor->dev,
> +                     "error while reading status register\n");
> +             return -EINVAL;
> +     }
> +     sr_cr[0] = ret;
> +     sr_cr[1] |= CR_QUAD_EN_SPAN;
> +
> +     write_enable(nor);
> +
> +     ret = nor->write_reg(nor, SPINOR_OP_WRSR, sr_cr, 2);
> +     if (ret < 0) {
> +             dev_err(nor->dev,
> +                     "error while writing configuration register\n");
> +             return -EINVAL;
> +     }
> +
> +     ret = spi_nor_wait_till_ready(nor);
> +     if (ret < 0) {
> +             dev_err(nor->dev, "error while waiting for WRSR completion\n");
> +             return ret;
> +     }
> +
> +     /* Read back and check it. */
> +     ret = read_cr(nor);
> +     if (!(ret > 0 && (ret & CR_QUAD_EN_SPAN))) {
> +             dev_err(nor->dev, "Spansion Quad bit not set\n");
> +             return -EINVAL;
> +     }
> +
> +     return 0;
> +}

kerneldoc . What does sr2 mean? (I know what it means, but kerneldoc
should explain it)

> +static int sr2_bit7_quad_enable(struct spi_nor *nor)
> +{
> +     u8 sr2;
> +     int ret;
> +
> +     /* Check current Quad Enable bit value. */
> +     ret = nor->read_reg(nor, SPINOR_OP_RDSR2, &sr2, 1);
> +     if (ret)
> +             return ret;
> +     if (sr2 & SR2_QUAD_EN_BIT7)
> +             return 0;
> +
> +     /* Update the Quad Enable bit. */
> +     sr2 |= SR2_QUAD_EN_BIT7;
> +
> +     write_enable(nor);
> +
> +     ret = nor->write_reg(nor, SPINOR_OP_WRSR2, &sr2, 1);
> +     if (ret < 0) {
> +             dev_err(nor->dev,
> +                     "error while writing status register 2\n");

Maybe introduce a new variable dev = nor->dev and avoid breaking the
lines like that ? DTTO above.

> +             return -EINVAL;
> +     }
> +
> +     ret = spi_nor_wait_till_ready(nor);
> +     if (ret < 0) {
> +             dev_err(nor->dev, "error while waiting for WRSR2 completion\n");
> +             return ret;
> +     }
> +
> +     /* Read back and check it. */
> +     ret = nor->read_reg(nor, SPINOR_OP_RDSR2, &sr2, 1);
> +     if (!(ret > 0 && (sr2 & SR2_QUAD_EN_BIT7))) {
> +             dev_err(nor->dev, "SR2 Quad bit not set\n");
> +             return -EINVAL;
> +     }
> +
> +     return 0;
> +}
> +
>  static int spi_nor_check(struct spi_nor *nor)
>  {
>       if (!nor->dev || !nor->read || !nor->write ||
> @@ -1586,6 +1679,477 @@ spi_nor_set_pp_settings(struct spi_nor_pp_command *pp,
>       pp->proto = proto;
>  }
>  
> +/*
> + * SFDP parsing.
> + */
> +
> +static int spi_nor_read_sfdp(struct spi_nor *nor, u32 addr,
> +                          size_t len, void *buf)
> +{
> +     u8 addr_width, read_opcode, read_dummy;
> +     int ret;
> +
> +     read_opcode = nor->read_opcode;
> +     addr_width = nor->addr_width;
> +     read_dummy = nor->read_dummy;
> +
> +     nor->read_opcode = SPINOR_OP_RDSFDP;
> +     nor->addr_width = 3;
> +     nor->read_dummy = 8;
> +
> +     ret = nor->read(nor, addr, len, (u8 *)buf);
> +
> +     nor->read_opcode = read_opcode;
> +     nor->addr_width = addr_width;
> +     nor->read_dummy = read_dummy;
> +
> +     return (ret < 0) ? ret : 0;

Would it hurt to just propagate the ret from nor->read ?

> +}
> +
> +struct sfdp_parameter_header {
> +     u8              id_lsb;
> +     u8              minor;
> +     u8              major;
> +     u8              length; /* in double words */
> +     u8              parameter_table_pointer[3]; /* byte address */
> +     u8              id_msb;
> +};
> +
> +#define SFDP_PARAM_HEADER_ID(p)      (((p)->id_msb << 8) | (p)->id_lsb)
> +#define SFDP_PARAM_HEADER_PTP(p) \
> +     (((p)->parameter_table_pointer[2] << 16) | \
> +      ((p)->parameter_table_pointer[1] <<  8) | \
> +      ((p)->parameter_table_pointer[0] <<  0))
> +
> +#define SFDP_BFPT_ID         0xff00  /* Basic Flash Parameter Table */
> +#define SFDP_SECTOR_MAP_ID   0xff81  /* Sector Map Table */
> +
> +#define SFDP_SIGNATURE               0x50444653U
> +#define SFDP_JESD216_MAJOR   1
> +#define SFDP_JESD216_MINOR   0
> +#define SFDP_JESD216A_MINOR  5
> +#define SFDP_JESD216B_MINOR  6
> +
> +struct sfdp_header {
> +     u32             signature; /* Ox50444653U <=> "SFDP" */
> +     u8              minor;
> +     u8              major;
> +     u8              nph; /* 0-base number of parameter headers */
> +     u8              unused;
> +
> +     /* Basic Flash Parameter Table. */
> +     struct sfdp_parameter_header    bfpt_header;
> +};
> +
> +/* Basic Flash Parameter Table */
> +
> +/*
> + * JESD216B defines a Basic Flash Parameter Table of 16 DWORDs.
> + * They are indexed from 1 but C arrays are indexed from 0.
> + */
> +#define BFPT_DWORD(i)                ((i) - 1)
> +#define BFPT_DWORD_MAX               16
> +
> +/* The first revision of JESB216 defined only 9 DWORDs. */
> +#define BFPT_DWORD_MAX_JESD216                       9
> +
> +/* 1st DWORD. */
> +#define BFPT_DWORD1_FAST_READ_1_1_2          BIT(16)
> +#define BFPT_DWORD1_ADDRESS_BYTES_MASK               GENMASK(18, 17)
> +#define BFPT_DWORD1_ADDRESS_BYTES_3_ONLY     (0x0UL << 17)
> +#define BFPT_DWORD1_ADDRESS_BYTES_3_OR_4     (0x1UL << 17)
> +#define BFPT_DWORD1_ADDRESS_BYTES_4_ONLY     (0x2UL << 17)
> +#define BFPT_DWORD1_DTR                              BIT(19)
> +#define BFPT_DWORD1_FAST_READ_1_2_2          BIT(20)
> +#define BFPT_DWORD1_FAST_READ_1_4_4          BIT(21)
> +#define BFPT_DWORD1_FAST_READ_1_1_4          BIT(22)
> +
> +/* 5th DWORD. */
> +#define BFPT_DWORD5_FAST_READ_2_2_2          BIT(0)
> +#define BFPT_DWORD5_FAST_READ_4_4_4          BIT(4)
> +
> +/* 11th DWORD. */
> +#define BFPT_DWORD11_PAGE_SIZE_SHIFT         4
> +#define BFPT_DWORD11_PAGE_SIZE_MASK          GENMASK(7, 4)
> +
> +/* 15th DWORD. */
> +
> +/*
> + * (from JESD216B)
> + * Quad Enable Requirements (QER):
> + * - 000b: Device does not have a QE bit. Device detects 1-1-4 and 1-4-4
> + *         reads based on instruction. DQ3/HOLD# functions are hold during
> + *         instruction phase.
> + * - 001b: QE is bit 1 of status register 2. It is set via Write Status with
> + *         two data bytes where bit 1 of the second byte is one.
> + *         [...]
> + *         Writing only one byte to the status register has the side-effect 
> of
> + *         clearing status register 2, including the QE bit. The 100b code is
> + *         used if writing one byte to the status register does not modify
> + *         status register 2.
> + * - 010b: QE is bit 6 of status register 1. It is set via Write Status with
> + *         one data byte where bit 6 is one.
> + *         [...]
> + * - 011b: QE is bit 7 of status register 2. It is set via Write status
> + *         register 2 instruction 3Eh with one data byte where bit 7 is one.
> + *         [...]
> + *         The status register 2 is read using instruction 3Fh.
> + * - 100b: QE is bit 1 of status register 2. It is set via Write Status with
> + *         two data bytes where bit 1 of the second byte is one.
> + *         [...]
> + *         In contrast to the 001b code, writing one byte to the status
> + *         register does not modify status register 2.
> + * - 101b: QE is bit 1 of status register 2. Status register 1 is read using
> + *         Read Status instruction 05h. Status register2 is read using
> + *         instruction 35h. QE is set via Writ Status instruction 01h with
> + *         two data bytes where bit 1 of the second byte is one.
> + *         [...]
> + */
> +#define BFPT_DWORD15_QER_MASK                        GENMASK(22, 20)
> +#define BFPT_DWORD15_QER_NONE                        (0x0UL << 20) /* Micron 
> */
> +#define BFPT_DWORD15_QER_SR2_BIT1_BUGGY              (0x1UL << 20)
> +#define BFPT_DWORD15_QER_SR1_BIT6            (0x2UL << 20) /* Macronix */
> +#define BFPT_DWORD15_QER_SR2_BIT7            (0x3UL << 20)
> +#define BFPT_DWORD15_QER_SR2_BIT1_NO_RD              (0x4UL << 20)
> +#define BFPT_DWORD15_QER_SR2_BIT1            (0x5UL << 20) /* Spansion */
> +
> +struct sfdp_bfpt {
> +     u32     dwords[BFPT_DWORD_MAX];
> +};
> +
> +/* Fast Read settings. */
> +
> +static inline void
> +spi_nor_set_read_settings_from_bfpt(struct spi_nor_read_command *read,
> +                                 u16 half,
> +                                 enum spi_nor_protocol proto)
> +{
> +     read->num_mode_clocks = (half >> 5) & 0x07;
> +     read->num_wait_states = (half >> 0) & 0x1f;
> +     read->opcode = (half >> 8) & 0xff;
> +     read->proto = proto;
> +}
> +
> +struct sfdp_bfpt_read {
> +     /* The Fast Read x-y-z hardware capability in params->hwcaps.mask. */
> +     u32                     hwcaps;
> +
> +     /*
> +      * The <supported_bit> bit in <supported_dword> BFPT DWORD tells us
> +      * whether the Fast Read x-y-z command is supported.
> +      */
> +     u32                     supported_dword;
> +     u32                     supported_bit;
> +
> +     /*
> +      * The half-word at offset <setting_shift> in <setting_dword> BFPT DWORD
> +      * encodes the op code, the number of mode clocks and the number of wait
> +      * states to be used by Fast Read x-y-z command.
> +      */
> +     u32                     settings_dword;
> +     int                     settings_shift;
> +
> +     /* The SPI protocol for this Fast Read x-y-z command. */
> +     enum spi_nor_protocol   proto;
> +};
> +
> +static const struct sfdp_bfpt_read sfdp_bfpt_reads[] = {
> +     /* Fast Read 1-1-2 */
> +     {
> +             SNOR_HWCAPS_READ_1_1_2,
> +             BFPT_DWORD(1), BIT(16), /* Supported bit */
> +             BFPT_DWORD(4), 0,       /* Settings */
> +             SNOR_PROTO_1_1_2,
> +     },
> +
> +     /* Fast Read 1-2-2 */
> +     {
> +             SNOR_HWCAPS_READ_1_2_2,
> +             BFPT_DWORD(1), BIT(20), /* Supported bit */
> +             BFPT_DWORD(4), 16,      /* Settings */
> +             SNOR_PROTO_1_2_2,
> +     },
> +
> +     /* Fast Read 2-2-2 */
> +     {
> +             SNOR_HWCAPS_READ_2_2_2,
> +             BFPT_DWORD(5),  BIT(0), /* Supported bit */
> +             BFPT_DWORD(6), 16,      /* Settings */
> +             SNOR_PROTO_2_2_2,
> +     },
> +
> +     /* Fast Read 1-1-4 */
> +     {
> +             SNOR_HWCAPS_READ_1_1_4,
> +             BFPT_DWORD(1), BIT(22), /* Supported bit */
> +             BFPT_DWORD(3), 16,      /* Settings */
> +             SNOR_PROTO_1_1_4,
> +     },
> +
> +     /* Fast Read 1-4-4 */
> +     {
> +             SNOR_HWCAPS_READ_1_4_4,
> +             BFPT_DWORD(1), BIT(21), /* Supported bit */
> +             BFPT_DWORD(3), 0,               /* Settings */
> +             SNOR_PROTO_1_4_4,
> +     },
> +
> +     /* Fast Read 4-4-4 */
> +     {
> +             SNOR_HWCAPS_READ_4_4_4,
> +             BFPT_DWORD(5), BIT(4),  /* Supported bit */
> +             BFPT_DWORD(7), 16,      /* Settings */
> +             SNOR_PROTO_4_4_4,
> +     },
> +};
> +
> +struct sfdp_bfpt_erase {
> +     /*
> +      * The half-word at offset <shift> in DWORD <dwoard> encodes the
> +      * op code and erase sector size to be used by Sector Erase commands.
> +      */
> +     u32                     dword;
> +     int                     shift;

Should the shift be unsigned too ?

> +};
> +
> +static const struct sfdp_bfpt_erase sfdp_bfpt_erases[] = {
> +     /* Erase Type 1 in DWORD8 bits[15:0] */
> +     {BFPT_DWORD(8), 0},
> +
> +     /* Erase Type 2 in DWORD8 bits[31:16] */
> +     {BFPT_DWORD(8), 16},
> +
> +     /* Erase Type 3 in DWORD9 bits[15:0] */
> +     {BFPT_DWORD(9), 0},
> +
> +     /* Erase Type 4 in DWORD9 bits[31:16] */
> +     {BFPT_DWORD(9), 16},
> +};
> +
> +static int spi_nor_hwcaps_read2cmd(u32 hwcaps);
> +
> +static int spi_nor_parse_bfpt(struct spi_nor *nor,
> +                           const struct sfdp_parameter_header *bfpt_header,
> +                           struct spi_nor_flash_parameter *params)
> +{
> +     struct mtd_info *mtd = &nor->mtd;
> +     struct sfdp_bfpt bfpt;
> +     size_t len;
> +     int i, cmd, err;
> +     u32 addr;
> +     u16 half;
> +
> +     /* JESD216 Basic Flash Parameter Table length is at least 9 DWORDs. */
> +     if (bfpt_header->length < BFPT_DWORD_MAX_JESD216)
> +             return -EINVAL;
> +
> +     /* Read the Basic Flash Parameter Table. */
> +     len = min_t(size_t, sizeof(bfpt),
> +                 bfpt_header->length * sizeof(uint32_t));

sizeof(u32) , nuke all the uint.*_t .

> +     addr = SFDP_PARAM_HEADER_PTP(bfpt_header);
> +     memset(&bfpt, 0, sizeof(bfpt));
> +     err = spi_nor_read_sfdp(nor,  addr, len, &bfpt);
> +     if (err)
> +             return err;
> +
> +     /* Fix endianness of the BFPT DWORDs. */
> +     for (i = 0; i < BFPT_DWORD_MAX; i++)
> +             bfpt.dwords[i] = le32_to_cpu(bfpt.dwords[i]);
> +
> +     /* Number of address bytes. */
> +     switch (bfpt.dwords[BFPT_DWORD(1)] & BFPT_DWORD1_ADDRESS_BYTES_MASK) {
> +     case BFPT_DWORD1_ADDRESS_BYTES_3_ONLY:
> +             nor->addr_width = 3;
> +             break;
> +
> +     case BFPT_DWORD1_ADDRESS_BYTES_4_ONLY:
> +             nor->addr_width = 4;
> +             break;
> +
> +     default:
> +             break;
> +     }
> +
> +     /* Flash Memory Density (in bits). */
> +     params->size = bfpt.dwords[BFPT_DWORD(2)];
> +     if (params->size & BIT(31)) {
> +             params->size &= ~BIT(31);
> +             params->size = 1ULL << params->size;
> +     } else {
> +             params->size++;
> +     }
> +     params->size >>= 3; /* Convert to bytes. */
> +
> +     /* Fast Read settings. */
> +     for (i = 0; i < ARRAY_SIZE(sfdp_bfpt_reads); i++) {
> +             const struct sfdp_bfpt_read *rd = &sfdp_bfpt_reads[i];
> +             struct spi_nor_read_command *read;
> +
> +             if (!(bfpt.dwords[rd->supported_dword] & rd->supported_bit)) {
> +                     params->hwcaps.mask &= ~rd->hwcaps;
> +                     continue;
> +             }
> +
> +             params->hwcaps.mask |= rd->hwcaps;
> +             cmd = spi_nor_hwcaps_read2cmd(rd->hwcaps);
> +             read = &params->reads[cmd];
> +             half = bfpt.dwords[rd->settings_dword] >> rd->settings_shift;
> +             spi_nor_set_read_settings_from_bfpt(read, half, rd->proto);
> +     }
> +
> +     /* Sector Erase settings. */
> +     for (i = 0; i < ARRAY_SIZE(sfdp_bfpt_erases); i++) {
> +             const struct sfdp_bfpt_erase *er = &sfdp_bfpt_erases[i];
> +             uint32_t erasesize;
> +             u8 opcode;
> +
> +             half = bfpt.dwords[er->dword] >> er->shift;
> +             erasesize = half & 0xff;
> +
> +             /* erasesize == 0 means this Erase Type is not supported. */
> +             if (!erasesize)
> +                     continue;
> +
> +             erasesize = (1U << erasesize);

Drop the parenthesis .

> +             opcode = (half >> 8) & 0xff;
> +#ifdef CONFIG_MTD_SPI_NOR_USE_4K_SECTORS
> +             if (erasesize == 4096) {
> +                     nor->erase_opcode = opcode;
> +                     mtd->erasesize = erasesize;
> +                     break;
> +             }
> +#endif
> +             if (!mtd->erasesize || mtd->erasesize < erasesize) {
> +                     nor->erase_opcode = opcode;
> +                     mtd->erasesize = erasesize;
> +             }
> +     }
> +
> +     /* Stop here if not JESD216 rev A or later. */
> +     if (bfpt_header->length < BFPT_DWORD_MAX)
> +             return 0;
> +
> +     /* Page size: this field specifies 'N' so the page size = 2^N bytes. */
> +     params->page_size = bfpt.dwords[BFPT_DWORD(11)];
> +     params->page_size &= BFPT_DWORD11_PAGE_SIZE_MASK;
> +     params->page_size >>= BFPT_DWORD11_PAGE_SIZE_SHIFT;
> +     params->page_size = (1U << params->page_size);

Drop the ()

> +     /* Enable Quad I/O. */
> +     switch (bfpt.dwords[BFPT_DWORD(15)] & BFPT_DWORD15_QER_MASK) {
> +     default:
> +     case BFPT_DWORD15_QER_NONE:
> +             params->quad_enable = NULL;
> +             break;
> +
> +     case BFPT_DWORD15_QER_SR2_BIT1_BUGGY:
> +     case BFPT_DWORD15_QER_SR2_BIT1_NO_RD:
> +             params->quad_enable = spansion_quad_enable;
> +             break;
> +
> +     case BFPT_DWORD15_QER_SR1_BIT6:
> +             params->quad_enable = macronix_quad_enable;
> +             break;
> +
> +     case BFPT_DWORD15_QER_SR2_BIT7:
> +             params->quad_enable = sr2_bit7_quad_enable;
> +             break;
> +
> +     case BFPT_DWORD15_QER_SR2_BIT1:
> +             params->quad_enable = spansion_new_quad_enable;
> +             break;

Is default: needed here ?

> +     }
> +
> +     return 0;
> +}
> +
> +static int spi_nor_parse_sfdp(struct spi_nor *nor,
> +                           struct spi_nor_flash_parameter *params)
> +{
> +     const struct sfdp_parameter_header *param_header, *bfpt_header;
> +     struct sfdp_parameter_header *param_headers = NULL;
> +     struct sfdp_header header;
> +     size_t psize;
> +     int i, err;
> +
> +     /* Get the SFDP header. */
> +     err = spi_nor_read_sfdp(nor, 0, sizeof(header), &header);
> +     if (err)
> +             return err;
> +
> +     /* Check the SFDP header version. */
> +     if (le32_to_cpu(header.signature) != SFDP_SIGNATURE ||
> +         header.major != SFDP_JESD216_MAJOR ||
> +         header.minor < SFDP_JESD216_MINOR)
> +             return -EINVAL;
> +
> +     /*
> +      * Verify that the first and only mandatory parameter header is a
> +      * Basic Flash Parameter Table header as specified in JESD216.
> +      */
> +     bfpt_header = &header.bfpt_header;
> +     if (SFDP_PARAM_HEADER_ID(bfpt_header) != SFDP_BFPT_ID ||
> +         bfpt_header->major != SFDP_JESD216_MAJOR)
> +             return -EINVAL;
> +
> +     /* Allocate memory for parameter headers. */
> +     if (header.nph) {
> +             psize = header.nph * sizeof(*param_headers);
> +
> +             param_headers = kmalloc(psize, GFP_KERNEL);

devm_() ?

> +             if (!param_headers)
> +                     return -ENOMEM;
> +
> +             err = spi_nor_read_sfdp(nor, sizeof(header),
> +                                     psize, param_headers);
> +             if (err) {
> +                     dev_err(nor->dev,
> +                             "failed to read SFDP parameter headers\n");
> +                     goto exit;
> +             }
> +     }
> +
> +     /*
> +      * Check other parameter headers to get the latest revision of
> +      * the basic flash parameter table.
> +      */
> +     for (i = 0; i < header.nph; i++) {
> +             param_header = &param_headers[i];
> +
> +             if (SFDP_PARAM_HEADER_ID(param_header) == SFDP_BFPT_ID &&
> +                 param_header->major == SFDP_JESD216_MAJOR &&
> +                 (param_header->minor > bfpt_header->minor ||
> +                  (param_header->minor == bfpt_header->minor &&
> +                   param_header->length > bfpt_header->length)))

I'm not comfortable with this indent ...

> +                     bfpt_header = param_header;
> +     }

Newline.

> +     err = spi_nor_parse_bfpt(nor, bfpt_header, params);
> +     if (err)
> +             goto exit;
> +
> +     /* Parse other parameter headers. */
> +     for (i = 0; i < header.nph; i++) {
> +             param_header = &param_headers[i];
> +
> +             switch (SFDP_PARAM_HEADER_ID(param_header)) {
> +             case SFDP_SECTOR_MAP_ID:
> +                     dev_info(nor->dev,
> +                              "non-uniform erase sector maps are not 
> supported yet.\n");
> +                     break;
> +
> +             default:
> +                     break;
> +             }
> +
> +             if (err)
> +                     goto exit;
> +     }
> +
> +exit:
> +     kfree(param_headers);
> +     return err;
> +}
> +
>  static int spi_nor_init_params(struct spi_nor *nor,
>                              const struct flash_info *info,
>                              struct spi_nor_flash_parameter *params)
> @@ -1646,6 +2210,22 @@ static int spi_nor_init_params(struct spi_nor *nor,
>               }
>       }
>  
> +     /* Override the parameters with data read from SFDP tables. */
> +     nor->addr_width = 0;
> +     nor->mtd.erasesize = 0;
> +     if ((info->flags & (SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ)) &&
> +         !(info->flags & SPI_NOR_SKIP_SFDP)) {
> +             struct spi_nor_flash_parameter sfdp_params;
> +
> +             memcpy(&sfdp_params, params, sizeof(sfdp_params));
> +             if (spi_nor_parse_sfdp(nor, &sfdp_params)) {
> +                     nor->addr_width = 0;
> +                     nor->mtd.erasesize = 0;
> +             } else {
> +                     memcpy(params, &sfdp_params, sizeof(*params));
> +             }
> +     }
> +
>       return 0;
>  }
>  
> @@ -1757,6 +2337,10 @@ static int spi_nor_select_erase(struct spi_nor *nor,
>  {
>       struct mtd_info *mtd = &nor->mtd;
>  
> +     /* Do nothing if already configured from SFDP. */
> +     if (mtd->erasesize)
> +             return 0;
> +
>  #ifdef CONFIG_MTD_SPI_NOR_USE_4K_SECTORS
>       /* prefer "small sector" erase if possible */
>       if (info->flags & SECT_4K) {
> @@ -1989,9 +2573,11 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
>       if (ret)
>               return ret;
>  
> -     if (info->addr_width)
> +     if (nor->addr_width) {
> +             /* already configured by spi_nor_setup() */
> +     } else if (info->addr_width) {
>               nor->addr_width = info->addr_width;
> -     else if (mtd->size > 0x1000000) {
> +     } else if (mtd->size > 0x1000000) {
>               /* enable 4-byte addressing if the device exceeds 16MiB */
>               nor->addr_width = 4;
>               if (JEDEC_MFR(info) == SNOR_MFR_SPANSION ||
> diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
> index 55faa2f07cca..0df3638ff0b8 100644
> --- a/include/linux/mtd/spi-nor.h
> +++ b/include/linux/mtd/spi-nor.h
> @@ -41,6 +41,8 @@
>  #define SPINOR_OP_WREN               0x06    /* Write enable */
>  #define SPINOR_OP_RDSR               0x05    /* Read status register */
>  #define SPINOR_OP_WRSR               0x01    /* Write status register 1 byte 
> */
> +#define SPINOR_OP_RDSR2              0x3f    /* Read status register 2 */
> +#define SPINOR_OP_WRSR2              0x3e    /* Write status register 2 */
>  #define SPINOR_OP_READ               0x03    /* Read data bytes (low 
> frequency) */
>  #define SPINOR_OP_READ_FAST  0x0b    /* Read data bytes (high frequency) */
>  #define SPINOR_OP_READ_1_1_2 0x3b    /* Read data bytes (Dual Output SPI) */
> @@ -56,6 +58,7 @@
>  #define SPINOR_OP_CHIP_ERASE 0xc7    /* Erase whole flash chip */
>  #define SPINOR_OP_SE         0xd8    /* Sector erase (usually 64KiB) */
>  #define SPINOR_OP_RDID               0x9f    /* Read JEDEC ID */
> +#define SPINOR_OP_RDSFDP     0x5a    /* Read SFDP */
>  #define SPINOR_OP_RDCR               0x35    /* Read configuration register 
> */
>  #define SPINOR_OP_RDFSR              0x70    /* Read flag status register */
>  
> @@ -128,6 +131,9 @@
>  /* Configuration Register bits. */
>  #define CR_QUAD_EN_SPAN              BIT(1)  /* Spansion Quad I/O */
>  
> +/* Status Register 2 bits. */
> +#define SR2_QUAD_EN_BIT7     BIT(7)
> +
>  /* Supported SPI protocols */
>  #define SNOR_PROTO_INST_MASK GENMASK(23, 16)
>  #define SNOR_PROTO_INST_SHIFT        16
> 


-- 
Best regards,
Marek Vasut

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