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

Álvaro Fernández Rojas
2018-01-11T17:42:03Z

El 11/01/2018 a las 18:17, Jagan Teki escribió:
> 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?
No, I didn't try that.
Can you provide an example of that?