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Subject[PATCH net-next v2 1/7] iopoll: introduce read_poll_timeout macro
Date
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>
---
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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