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| author | Kai-Heng Feng <kai.heng.feng@canonical.com> | 2020-04-24 21:49:14 +0300 |
|---|---|---|
| committer | Kalle Valo <kvalo@codeaurora.org> | 2020-05-06 11:29:25 +0300 |
| commit | 57a29df341466b5cca43ba3d2d7064426727d7c3 (patch) | |
| tree | f09c0c62506760c9bb47d912482e4df12491af8a /include/linux/iopoll.h | |
| parent | ea1b3bc6d5ad95fef32811bec7df37f51809f4e1 (diff) | |
| download | linux-57a29df341466b5cca43ba3d2d7064426727d7c3.tar.xz | |
iopoll: Introduce read_poll_timeout_atomic macro
Like read_poll_timeout, an atomic variant for multiple parameter read
function can be useful.
Will be used by a later patch.
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200424184918.30360-1-kai.heng.feng@canonical.com
Diffstat (limited to 'include/linux/iopoll.h')
| -rw-r--r-- | include/linux/iopoll.h | 62 |
1 files changed, 43 insertions, 19 deletions
diff --git a/include/linux/iopoll.h b/include/linux/iopoll.h index cb20c733b15a..bc89ac625f26 100644 --- a/include/linux/iopoll.h +++ b/include/linux/iopoll.h @@ -58,6 +58,48 @@ }) /** + * read_poll_timeout_atomic - Periodically poll an address until a condition is + * met or a timeout occurs + * @op: accessor function (takes @addr as its only argument) + * @addr: Address to poll + * @val: Variable to read the value into + * @cond: Break condition (usually involving @val) + * @delay_us: Time to udelay between reads in us (0 tight-loops). Should + * be less than ~10us since udelay is used (see + * Documentation/timers/timers-howto.rst). + * @timeout_us: Timeout in us, 0 means never timeout + * @delay_before_read: if it is true, delay @delay_us before read. + * + * Returns 0 on success and -ETIMEDOUT upon a timeout. In either + * case, the last read value at @args is stored in @val. + * + * When available, you'll probably want to use one of the specialized + * macros defined below rather than this macro directly. + */ +#define read_poll_timeout_atomic(op, val, cond, delay_us, timeout_us, \ + delay_before_read, args...) \ +({ \ + u64 __timeout_us = (timeout_us); \ + unsigned long __delay_us = (delay_us); \ + ktime_t __timeout = ktime_add_us(ktime_get(), __timeout_us); \ + if (delay_before_read && __delay_us) \ + udelay(__delay_us); \ + for (;;) { \ + (val) = op(args); \ + if (cond) \ + break; \ + if (__timeout_us && \ + ktime_compare(ktime_get(), __timeout) > 0) { \ + (val) = op(args); \ + break; \ + } \ + if (__delay_us) \ + udelay(__delay_us); \ + } \ + (cond) ? 0 : -ETIMEDOUT; \ +}) + +/** * readx_poll_timeout - Periodically poll an address until a condition is met or a timeout occurs * @op: accessor function (takes @addr as its only argument) * @addr: Address to poll @@ -96,25 +138,7 @@ * macros defined below rather than this macro directly. */ #define readx_poll_timeout_atomic(op, addr, val, cond, delay_us, timeout_us) \ -({ \ - u64 __timeout_us = (timeout_us); \ - unsigned long __delay_us = (delay_us); \ - ktime_t __timeout = ktime_add_us(ktime_get(), __timeout_us); \ - for (;;) { \ - (val) = op(addr); \ - if (cond) \ - break; \ - if (__timeout_us && \ - ktime_compare(ktime_get(), __timeout) > 0) { \ - (val) = op(addr); \ - break; \ - } \ - if (__delay_us) \ - udelay(__delay_us); \ - } \ - (cond) ? 0 : -ETIMEDOUT; \ -}) - + read_poll_timeout_atomic(op, val, cond, delay_us, timeout_us, false, addr) #define readb_poll_timeout(addr, val, cond, delay_us, timeout_us) \ readx_poll_timeout(readb, addr, val, cond, delay_us, timeout_us) |