add readx_poll_timeout() required for 5.7.6 drm

with help from cheloha@

1 files changed, 34 insertions, 0 deletions

diff --git a/sys/dev/pci/drm/include/linux/iopoll.h b/sys/dev/pci/drm/include/linux/iopoll.h
new file mode 100644
index 00000000000..4a2d42842aa
--- /dev/null
+++ b/sys/dev/pci/drm/include/linux/iopoll.h
@@ -0,0 +1,34 @@
+/* Public domain. */
+
+#ifndef _LINUX_IOPOLL_H
+#define _LINUX_IOPOLL_H
+
+#define readx_poll_timeout(op, addr, val, cond, sleep_us, timeout_us)	\
+({									\
+	struct timeval __end, __now, __timeout_tv;			\
+	int __timed_out = 0;						\
+									\
+	if (timeout_us) {						\
+		microuptime(&__now);					\
+		USEC_TO_TIMEVAL(timeout_us, &__timeout_tv);		\
+		timeradd(&__now, &__timeout_tv, &__end);		\
+	}								\
+									\
+	for (;;) {							\
+		(val) = (op)(addr);					\
+		if (cond)						\
+			break;						\
+		if (timeout_us) {					\
+			microuptime(&__now);				\
+			if (timercmp(&__end, &__now, <=)) {		\
+				__timed_out = 1;			\
+				break;					\
+			}						\
+		}							\
+		if (sleep_us)						\
+			delay((sleep_us) / 2);				\
+	}								\
+	(__timed_out) ? -ETIMEDOUT : 0;					\
+})
+
+#endif