[U-Boot] [PATCH v8 01/12] wait_bit: add 8/16/32 BE/LE versions of wait_for_bit

[Jagan Teki]

On Thu, Jan 11, 2018 at 10:41 PM, Álvaro Fernández Rojas
<noltari at gmail.com> wrote:
> Add 8/16/32 bits and BE/LE versions of wait_for_bit.
> This is needed for reading registers that are not aligned to 32 bits, and for
> Big Endian platforms.
>
> Signed-off-by: Álvaro Fernández Rojas <noltari at gmail.com>
> Reviewed-by: Daniel Schwierzeck <daniel.schwierzeck at gmail.com>
> Reviewed-by: Jagan Teki <jagan at openedev.com>
> ---
>  v8: no changes.
>  v7: Introduce changes suggested by Daniel Schwierzeck:
>  - Use const void* reg for compatibility with 64 bit systems.
>  - Remove prefix and use __func__ instead.
>  v6: Introduce changes suggested by Jagan Teki:
>  - Switch to wait_for_bit instead of infinite loop.
>
>  include/wait_bit.h | 61 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 61 insertions(+)
>
> diff --git a/include/wait_bit.h b/include/wait_bit.h
> index 06ad43a122..bde6d2cfc3 100644
> --- a/include/wait_bit.h
> +++ b/include/wait_bit.h
> @@ -69,5 +69,66 @@ static inline int wait_for_bit(const char *prefix, const u32 *reg,
>         return -ETIMEDOUT;
>  }
>
> +/**
> + * wait_for_bit_x()    waits for bit set/cleared in register
> + *
> + * Function polls register waiting for specific bit(s) change
> + * (either 0->1 or 1->0). It can fail under two conditions:
> + * - Timeout
> + * - User interaction (CTRL-C)
> + * Function succeeds only if all bits of masked register are set/cleared
> + * (depending on set option).
> + *
> + * @param reg          Register that will be read (using read_x())
> + * @param mask         Bit(s) of register that must be active
> + * @param set          Selects wait condition (bit set or clear)
> + * @param timeout_ms   Timeout (in milliseconds)
> + * @param breakable    Enables CTRL-C interruption
> + * @return             0 on success, -ETIMEDOUT or -EINTR on failure
> + */
> +
> +#define BUILD_WAIT_FOR_BIT(sfx, type, read)                            \
> +                                                                       \
> +static inline int wait_for_bit_##sfx(const void *reg,                  \
> +                                    const type mask,                   \
> +                                    const bool set,                    \
> +                                    const unsigned int timeout_ms,     \
> +                                    const bool breakable)              \
> +{                                                                      \
> +       type val;                                                       \
> +       unsigned long start = get_timer(0);                             \
> +                                                                       \
> +       while (1) {                                                     \
> +               val = read(reg);                                        \
> +                                                                       \
> +               if (!set)                                               \
> +                       val = ~val;                                     \
> +                                                                       \
> +               if ((val & mask) == mask)                               \
> +                       return 0;                                       \
> +                                                                       \
> +               if (get_timer(start) > timeout_ms)                      \
> +                       break;                                          \
> +                                                                       \
> +               if (breakable && ctrlc()) {                             \
> +                       puts("Abort\n");                                \
> +                       return -EINTR;                                  \
> +               }                                                       \
> +                                                                       \
> +               udelay(1);                                              \
> +               WATCHDOG_RESET();                                       \
> +       }                                                               \
> +                                                                       \
> +       debug("%s: Timeout (reg=%p mask=%x wait_set=%i)\n", __func__,   \
> +             reg, mask, set);                                          \
> +                                                                       \
> +       return -ETIMEDOUT;                                              \
> +}
> +
> +BUILD_WAIT_FOR_BIT(8, u8, readb)
> +BUILD_WAIT_FOR_BIT(le16, u16, readw)
> +BUILD_WAIT_FOR_BIT(be16, u16, readw_be)
> +BUILD_WAIT_FOR_BIT(le32, u32, readl)
> +BUILD_WAIT_FOR_BIT(be32, u32, readl_be)

I'm still thinking here, can't we try to use typeof and get rid of
these endianess and macros? did you tried that?