Messages in this thread Patch in this message | | | From | Dejin Zheng <> | Subject | [PATCH net-next v4 1/9] iopoll: introduce read_poll_timeout macro | Date | Sun, 22 Mar 2020 14:55:47 +0800 |
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this macro is an extension of readx_poll_timeout macro. the accessor function op just supports only one parameter in the readx_poll_timeout macro, but this macro can supports multiple variable parameters for it. so functions like phy_read(struct phy_device *phydev, u32 regnum) and phy_read_mmd(struct phy_device *phydev, int devad, u32 regnum) can also use this poll timeout framework.
Signed-off-by: Dejin Zheng <zhengdejin5@gmail.com> --- v3 -> v4: - no changed v2 -> v3: - no changed v1 -> v2: - no changed
include/linux/iopoll.h | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+)
diff --git a/include/linux/iopoll.h b/include/linux/iopoll.h index 35e15dfd4155..7d44a2e20267 100644 --- a/include/linux/iopoll.h +++ b/include/linux/iopoll.h @@ -13,6 +13,46 @@ #include <linux/errno.h> #include <linux/io.h> +/** + * read_poll_timeout - Periodically poll an address until a condition is + * met or a timeout occurs + * @op: accessor function (takes @args as its arguments) + * @val: Variable to read the value into + * @cond: Break condition (usually involving @val) + * @sleep_us: Maximum time to sleep between reads in us (0 + * tight-loops). Should be less than ~20ms since usleep_range + * is used (see Documentation/timers/timers-howto.rst). + * @timeout_us: Timeout in us, 0 means never timeout + * @args: arguments for @op poll + * + * Returns 0 on success and -ETIMEDOUT upon a timeout. In either + * case, the last read value at @args is stored in @val. Must not + * be called from atomic context if sleep_us or timeout_us are used. + * + * When available, you'll probably want to use one of the specialized + * macros defined below rather than this macro directly. + */ +#define read_poll_timeout(op, val, cond, sleep_us, timeout_us, args...) \ +({ \ + u64 __timeout_us = (timeout_us); \ + unsigned long __sleep_us = (sleep_us); \ + ktime_t __timeout = ktime_add_us(ktime_get(), __timeout_us); \ + might_sleep_if((__sleep_us) != 0); \ + for (;;) { \ + (val) = op(args); \ + if (cond) \ + break; \ + if (__timeout_us && \ + ktime_compare(ktime_get(), __timeout) > 0) { \ + (val) = op(args); \ + break; \ + } \ + if (__sleep_us) \ + usleep_range((__sleep_us >> 2) + 1, __sleep_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) -- 2.25.0
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