@@ -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)
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> --- v4 -> v5: - no changed v3 -> v4: - no changed v2 -> v3: - no changed v1 -> v2: - no changed include/linux/iopoll.h | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+)