[U-Boot] [PATCH] ARM: cfi_flash: Fix unaligned accesses to cfi_qry structure

[Gabbasov, Andrew]

> From: Gabbasov, Andrew
> Sent: Monday, April 29, 2013 13:34
> To: u-boot at lists.denx.de
> Subject: [U-Boot][PATCH] ARM: cfi_flash: Fix unaligned accesses to cfi_qry structure
> 
> Packed structure cfi_qry contains unaligned 16- and 32-bits members,
> accessing which causes problems when cfi_flash driver is compiled with
> -munaligned-access option: flash initialization hangs, probably
> due to data error.
> 
> This fix converts 16- and 32-bit members to byte arrays and uses special
> macros to access such fields. It removes possible unaligned accesses
> in cfi_flash driver.
> 
> Signed-off-by: Andrew Gabbasov <andrew_gabbasov at mentor.com>
> ---
>  drivers/mtd/cfi_flash.c |   23 +++++++++++++----------
>  include/mtd/cfi_flash.h |   18 +++++++++++-------
>  2 files changed, 24 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/mtd/cfi_flash.c b/drivers/mtd/cfi_flash.c
> index 60dbb78..2112ffc 100644
> --- a/drivers/mtd/cfi_flash.c
> +++ b/drivers/mtd/cfi_flash.c
> @@ -1636,13 +1636,16 @@ void flash_read_factory_serial (flash_info_t * info, void *buffer, int offset,
>   */
>  static void cfi_reverse_geometry(struct cfi_qry *qry)
>  {
> -       unsigned int i, j;
> -       u32 tmp;
> +       unsigned int i, j, k;
> +       u8 tmp;
> 
>         for (i = 0, j = qry->num_erase_regions - 1; i < j; i++, j--) {
> -               tmp = qry->erase_region_info[i];
> -               qry->erase_region_info[i] = qry->erase_region_info[j];
> -               qry->erase_region_info[j] = tmp;
> +               for (k = 0; k < 4; k++) {
> +                       tmp = qry->erase_region_info[k][i];
> +                       qry->erase_region_info[k][i] =
> +                               qry->erase_region_info[k][j];
> +                       qry->erase_region_info[k][j] = tmp;
> +               }
>         }
>  }
> 
> @@ -1891,7 +1894,7 @@ static int __flash_detect_cfi (flash_info_t * info, struct cfi_qry *qry)
>                     && flash_isequal (info, 0, FLASH_OFFSET_CFI_RESP + 2, 'Y')) {
>                         flash_read_cfi(info, qry, FLASH_OFFSET_CFI_RESP,
>                                         sizeof(struct cfi_qry));
> -                       info->interface = le16_to_cpu(qry->interface_desc);
> +                       info->interface = cfiqry_get16(qry->interface_desc);
> 
>                         info->cfi_offset = flash_offset_cfi[cfi_offset];
>                         debug ("device interface is %d\n",
> @@ -2053,8 +2056,8 @@ ulong flash_get_size (phys_addr_t base, int banknum)
>         info->start[0] = (ulong)map_physmem(base, info->portwidth, MAP_NOCACHE);
> 
>         if (flash_detect_cfi (info, &qry)) {
> -               info->vendor = le16_to_cpu(qry.p_id);
> -               info->ext_addr = le16_to_cpu(qry.p_adr);
> +               info->vendor = cfiqry_get16(qry.p_id);
> +               info->ext_addr = cfiqry_get16(qry.p_adr);
>                 num_erase_regions = qry.num_erase_regions;
> 
>                 if (info->ext_addr) {
> @@ -2140,7 +2143,7 @@ ulong flash_get_size (phys_addr_t base, int banknum)
>                                 break;
>                         }
> 
> -                       tmp = le32_to_cpu(qry.erase_region_info[i]);
> +                       tmp = cfiqry_get32(qry.erase_region_info[i]);
>                         debug("erase region %u: 0x%08lx\n", i, tmp);
> 
>                         erase_region_count = (tmp & 0xffff) + 1;
> @@ -2213,7 +2216,7 @@ ulong flash_get_size (phys_addr_t base, int banknum)
>                 }
> 
>                 info->sector_count = sect_cnt;
> -               info->buffer_size = 1 << le16_to_cpu(qry.max_buf_write_size);
> +               info->buffer_size = 1 << cfiqry_get16(qry.max_buf_write_size);
>                 tmp = 1 << qry.block_erase_timeout_typ;
>                 info->erase_blk_tout = tmp *
>                         (1 << qry.block_erase_timeout_max);
> diff --git a/include/mtd/cfi_flash.h b/include/mtd/cfi_flash.h
> index 966b5e0..30d6896 100644
> --- a/include/mtd/cfi_flash.h
> +++ b/include/mtd/cfi_flash.h
> @@ -131,10 +131,10 @@ typedef union {
>  /* CFI standard query structure */
>  struct cfi_qry {
>         u8      qry[3];
> -       u16     p_id;
> -       u16     p_adr;
> -       u16     a_id;
> -       u16     a_adr;
> +       u8      p_id[2];
> +       u8      p_adr[2];
> +       u8      a_id[2];
> +       u8      a_adr[2];
>         u8      vcc_min;
>         u8      vcc_max;
>         u8      vpp_min;
> @@ -148,10 +148,10 @@ struct cfi_qry {
>         u8      block_erase_timeout_max;
>         u8      chip_erase_timeout_max;
>         u8      dev_size;
> -       u16     interface_desc;
> -       u16     max_buf_write_size;
> +       u8      interface_desc[2];
> +       u8      max_buf_write_size[2];
>         u8      num_erase_regions;
> -       u32     erase_region_info[NUM_ERASE_REGIONS];
> +       u8      erase_region_info[4][NUM_ERASE_REGIONS];
>  } __attribute__((packed));
> 
>  struct cfi_pri_hdr {
> @@ -160,6 +160,10 @@ struct cfi_pri_hdr {
>         u8      minor_version;
>  } __attribute__((packed));
> 
> +#define cfiqry_get16(mp) ((u16)((mp)[0]) | ((u16)((mp)[1]) << 8))
> +#define cfiqry_get32(mp) ((u32)((mp)[0]) | ((u32)((mp)[1]) << 8) | \
> +                         ((u32)((mp)[2]) << 16) | ((u32)((mp)[3]) << 24))
> +
>  #ifndef CONFIG_SYS_FLASH_BANKS_LIST
>  #define CONFIG_SYS_FLASH_BANKS_LIST { CONFIG_SYS_FLASH_BASE }
>  #endif
> --
> 1.7.10.4

Unfortunately, I can't verify this fix for the boards with flash configuration,
requiring reversing geometry. So, if anybody could test it on such board,
I would greatly appreciate it.

Thanks.

Best regards,
Andrew