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

Jagan Teki
2018-01-11T17:17:44Z

On Thu, Jan 11, 2018 at 10:41 PM, Álvaro Fernández Rojas
<noltari@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@gmail.com>
> Reviewed-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
> Reviewed-by: Jagan Teki <jagan@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?