Re: [Qemu-devel] [PATCH 1/6] hw/sd.c: convert wp_groups in SDState to bitfield

[Peter Maydell]

On 2 April 2012 15:28, Igor Mitsyanko <address@hidden> wrote:
> Representing each group write protection flag with only one bit instead of int
> variable significantly reduces memory consumption.

Can we use the bitmap.h functions here rather than doing things
by hand? (scattered examples below, you get the idea)

> Signed-off-by: Igor Mitsyanko <address@hidden>
> ---
>  hw/sd.c |   36 ++++++++++++++++++++++--------------
>  1 files changed, 22 insertions(+), 14 deletions(-)
>
> diff --git a/hw/sd.c b/hw/sd.c
> index 07eb263..23e5f2f 100644
> --- a/hw/sd.c
> +++ b/hw/sd.c
> @@ -81,7 +81,7 @@ struct SDState {
>     uint8_t sd_status[64];
>     uint32_t vhs;
>     int wp_switch;
> -    int *wp_groups;
> +    uint8_t *wp_groups;
>     uint64_t size;
>     int blk_len;
>     uint32_t erase_start;
> @@ -415,7 +415,7 @@ static void sd_reset(SDState *sd, BlockDriverState *bdrv)
>     if (sd->wp_groups)
>         g_free(sd->wp_groups);
>     sd->wp_switch = bdrv ? bdrv_is_read_only(bdrv) : 0;
> -    sd->wp_groups = (int *) g_malloc0(sizeof(int) * sect);
> +    sd->wp_groups = (uint8_t *)g_malloc0((sect >> 3) + 1);

sd->wp_groups = bitmap_new(sect);

>     memset(sd->function_group, 0, sizeof(int) * 6);
>     sd->erase_start = 0;
>     sd->erase_end = 0;
> @@ -484,9 +484,11 @@ static void sd_erase(SDState *sd)
>     sd->erase_end = 0;
>     sd->csd[14] |= 0x40;
>
> -    for (i = start; i <= end; i ++)
> -        if (sd->wp_groups[i])
> +    for (i = start; i <= end; i++) {
> +        if (sd->wp_groups[i >> 3] & (1 << (i & 0x7))) {

if (test_bit(i, sd->wp_groups)) {

>             sd->card_status |= WP_ERASE_SKIP;
> +        }
> +    }
>  }
>
>  static uint32_t sd_wpbits(SDState *sd, uint64_t addr)
> @@ -496,9 +498,12 @@ static uint32_t sd_wpbits(SDState *sd, uint64_t addr)
>
>     wpnum = addr >> (HWBLOCK_SHIFT + SECTOR_SHIFT + WPGROUP_SHIFT);
>
> -    for (i = 0; i < 32; i ++, wpnum ++, addr += WPGROUP_SIZE)
> -        if (addr < sd->size && sd->wp_groups[wpnum])
> +    for (i = 0; i < 32; i++, wpnum++, addr += WPGROUP_SIZE) {
> +        if (addr < sd->size &&
> +                (sd->wp_groups[wpnum >> 3] & (1 << (wpnum & 0x7)))) {
>             ret |= (1 << i);
> +        }
> +    }
>
>     return ret;
>  }
> @@ -536,8 +541,9 @@ static void sd_function_switch(SDState *sd, uint32_t arg)
>
>  static inline int sd_wp_addr(SDState *sd, uint32_t addr)
>  {
> -    return sd->wp_groups[addr >>
> -            (HWBLOCK_SHIFT + SECTOR_SHIFT + WPGROUP_SHIFT)];
> +    unsigned int grp = addr >>
> +            (HWBLOCK_SHIFT + SECTOR_SHIFT + WPGROUP_SHIFT);
> +    return sd->wp_groups[grp >> 3] & (1 << (grp & 0x7)) ? 1 : 0;
>  }
>
>  static void sd_lock_command(SDState *sd)
> @@ -560,8 +566,8 @@ static void sd_lock_command(SDState *sd)
>             sd->card_status |= LOCK_UNLOCK_FAILED;
>             return;
>         }
> -        memset(sd->wp_groups, 0, sizeof(int) * (sd->size >>
> -                        (HWBLOCK_SHIFT + SECTOR_SHIFT + WPGROUP_SHIFT)));
> +        memset(sd->wp_groups, 0, 1 + (sd->size >>
> +                        (HWBLOCK_SHIFT + SECTOR_SHIFT + WPGROUP_SHIFT + 3)));

bitmap_zero(sd->wp_groups, number-of-bits-to-clear)

>         sd->csd[14] &= ~0x10;
>         sd->card_status &= ~CARD_IS_LOCKED;
>         sd->pwd_len = 0;
> @@ -1007,8 +1013,9 @@ static sd_rsp_type_t sd_normal_command(SDState *sd,
>             }
>
>             sd->state = sd_programming_state;
> -            sd->wp_groups[addr >> (HWBLOCK_SHIFT +
> -                            SECTOR_SHIFT + WPGROUP_SHIFT)] = 1;
> +            sd->wp_groups[addr >> (HWBLOCK_SHIFT + SECTOR_SHIFT +
> +                    WPGROUP_SHIFT + 3)] |= 1 << ((addr >> (HWBLOCK_SHIFT +
> +                            SECTOR_SHIFT + WPGROUP_SHIFT)) & 0x7);

set_bit(addr >> (HWBLOCK_SHIFT + SECTOR_SHIFT + WPGROUP_SHIFT), sd->wp_groups);

>             /* Bzzzzzzztt .... Operation complete.  */
>             sd->state = sd_transfer_state;
>             return sd_r1b;
> @@ -1027,8 +1034,9 @@ static sd_rsp_type_t sd_normal_command(SDState *sd,
>             }
>
>             sd->state = sd_programming_state;
> -            sd->wp_groups[addr >> (HWBLOCK_SHIFT +
> -                            SECTOR_SHIFT + WPGROUP_SHIFT)] = 0;
> +            sd->wp_groups[addr >> (HWBLOCK_SHIFT + SECTOR_SHIFT +
> +                    WPGROUP_SHIFT + 3)] &= ~(1 << ((addr >> (HWBLOCK_SHIFT +
> +                            SECTOR_SHIFT + WPGROUP_SHIFT)) & 0x7));
>             /* Bzzzzzzztt .... Operation complete.  */
>             sd->state = sd_transfer_state;
>             return sd_r1b;
> --
> 1.7.4.1
>