drm/i915: split out separate files for jiffies timeout and wait helpers

Add i915_jiffies.h and intel_display_jiffies.h for jiffies timeout and
wait helpers, and use them separately from i915 and display. This helps
reduce the display dependency on i915_utils.h.

Long term, both msecs_to_jiffies_timeout() and
wait_remaining_ms_from_jiffies() really belong in core kernel headers,
but for now unblock display refactoring.

Reviewed-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://patch.msgid.link/d8bc62b3a81afa05c849dde9b0f633572eaf5611.1761146196.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

15 files changed, 73 insertions, 37 deletions

diff --git a/drivers/gpu/drm/i915/display/intel_display_jiffies.h b/drivers/gpu/drm/i915/display/intel_display_jiffies.h
new file mode 100644
index 000000000000..c060c567e262
--- /dev/null
+++ b/drivers/gpu/drm/i915/display/intel_display_jiffies.h
@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: MIT */
+/* Copyright © 2025 Intel Corporation */
+
+#ifndef __INTEL_DISPLAY_JIFFIES_H__
+#define __INTEL_DISPLAY_JIFFIES_H__
+
+#include <linux/jiffies.h>
+
+static inline unsigned long msecs_to_jiffies_timeout(const unsigned int m)
+{
+	unsigned long j = msecs_to_jiffies(m);
+
+	return min_t(unsigned long, MAX_JIFFY_OFFSET, j + 1);
+}
+
+/*
+ * If you need to wait X milliseconds between events A and B, but event B
+ * doesn't happen exactly after event A, you record the timestamp (jiffies) of
+ * when event A happened, then just before event B you call this function and
+ * pass the timestamp as the first argument, and X as the second argument.
+ */
+static inline void
+wait_remaining_ms_from_jiffies(unsigned long timestamp_jiffies, int to_wait_ms)
+{
+	unsigned long target_jiffies, tmp_jiffies, remaining_jiffies;
+
+	/*
+	 * Don't re-read the value of "jiffies" every time since it may change
+	 * behind our back and break the math.
+	 */
+	tmp_jiffies = jiffies;
+	target_jiffies = timestamp_jiffies +
+			 msecs_to_jiffies_timeout(to_wait_ms);
+
+	if (time_after(target_jiffies, tmp_jiffies)) {
+		remaining_jiffies = target_jiffies - tmp_jiffies;
+		while (remaining_jiffies)
+			remaining_jiffies =
+			    schedule_timeout_uninterruptible(remaining_jiffies);
+	}
+}
+
+#endif /* __INTEL_DISPLAY_JIFFIES_H__ */
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index a3391b17571c..0277ac5fc64f 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -64,6 +64,7 @@
 #include "intel_ddi.h"
 #include "intel_de.h"
 #include "intel_display_driver.h"
+#include "intel_display_jiffies.h"
 #include "intel_display_regs.h"
 #include "intel_display_rpm.h"
 #include "intel_display_types.h"
diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.c b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
index 27f3716bdc1f..316b42b5a946 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
@@ -29,6 +29,7 @@
 
 #include "i915_utils.h"
 #include "intel_display_core.h"
+#include "intel_display_jiffies.h"
 #include "intel_display_types.h"
 #include "intel_dp.h"
 #include "intel_dp_link_training.h"
diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c b/drivers/gpu/drm/i915/display/intel_hdcp.c
index 531ee122bf82..0f624004104f 100644
--- a/drivers/gpu/drm/i915/display/intel_hdcp.c
+++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
@@ -22,6 +22,7 @@
 #include "i915_utils.h"
 #include "intel_connector.h"
 #include "intel_de.h"
+#include "intel_display_jiffies.h"
 #include "intel_display_power.h"
 #include "intel_display_power_well.h"
 #include "intel_display_regs.h"
diff --git a/drivers/gpu/drm/i915/display/intel_pmdemand.c b/drivers/gpu/drm/i915/display/intel_pmdemand.c
index d806c15db7ce..7ade35e05eb5 100644
--- a/drivers/gpu/drm/i915/display/intel_pmdemand.c
+++ b/drivers/gpu/drm/i915/display/intel_pmdemand.c
@@ -12,6 +12,7 @@
 #include "intel_bw.h"
 #include "intel_cdclk.h"
 #include "intel_de.h"
+#include "intel_display_jiffies.h"
 #include "intel_display_regs.h"
 #include "intel_display_trace.h"
 #include "intel_pmdemand.h"
diff --git a/drivers/gpu/drm/i915/display/intel_pps.c b/drivers/gpu/drm/i915/display/intel_pps.c
index 327e0de86f1e..0c2f48626d0c 100644
--- a/drivers/gpu/drm/i915/display/intel_pps.c
+++ b/drivers/gpu/drm/i915/display/intel_pps.c
@@ -12,6 +12,7 @@
 #include "i915_reg.h"
 #include "i915_utils.h"
 #include "intel_de.h"
+#include "intel_display_jiffies.h"
 #include "intel_display_power_well.h"
 #include "intel_display_regs.h"
 #include "intel_display_types.h"
diff --git a/drivers/gpu/drm/i915/display/intel_vblank.c b/drivers/gpu/drm/i915/display/intel_vblank.c
index 2fc0c1c0bb87..0e534be375ca 100644
--- a/drivers/gpu/drm/i915/display/intel_vblank.c
+++ b/drivers/gpu/drm/i915/display/intel_vblank.c
@@ -12,6 +12,7 @@
 #include "intel_color.h"
 #include "intel_crtc.h"
 #include "intel_de.h"
+#include "intel_display_jiffies.h"
 #include "intel_display_regs.h"
 #include "intel_display_types.h"
 #include "intel_vblank.h"
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
index 75f5b0e871ef..4542135b20d5 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_mman.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
@@ -16,12 +16,13 @@
 #include "i915_gem_evict.h"
 #include "i915_gem_gtt.h"
 #include "i915_gem_ioctls.h"
-#include "i915_gem_object.h"
 #include "i915_gem_mman.h"
+#include "i915_gem_object.h"
+#include "i915_gem_ttm.h"
+#include "i915_jiffies.h"
 #include "i915_mm.h"
 #include "i915_trace.h"
 #include "i915_user_extensions.h"
-#include "i915_gem_ttm.h"
 #include "i915_vma.h"
 
 static inline bool
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
index 1f4814968868..045fbdbbe183 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
@@ -10,6 +10,7 @@
 #include <drm/drm_buddy.h>
 
 #include "i915_drv.h"
+#include "i915_jiffies.h"
 #include "i915_ttm_buddy_manager.h"
 #include "intel_memory_region.h"
 #include "intel_region_ttm.h"
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c b/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c
index 8d4bb95f8424..dcd3a3047aa4 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c
@@ -4,6 +4,7 @@
  */
 
 #include "i915_drv.h"
+#include "i915_jiffies.h"
 #include "i915_request.h"
 
 #include "intel_context.h"
diff --git a/drivers/gpu/drm/i915/gt/selftest_execlists.c b/drivers/gpu/drm/i915/gt/selftest_execlists.c
index 0454eb1814bb..376f201a7650 100644
--- a/drivers/gpu/drm/i915/gt/selftest_execlists.c
+++ b/drivers/gpu/drm/i915/gt/selftest_execlists.c
@@ -11,6 +11,7 @@
 #include "gt/intel_reset.h"
 #include "gt/selftest_engine_heartbeat.h"
 
+#include "i915_jiffies.h"
 #include "i915_selftest.h"
 #include "selftests/i915_random.h"
 #include "selftests/igt_flush_test.h"
diff --git a/drivers/gpu/drm/i915/i915_config.c b/drivers/gpu/drm/i915/i915_config.c
index 24e5bb8a670e..3cb615ffa96d 100644
--- a/drivers/gpu/drm/i915/i915_config.c
+++ b/drivers/gpu/drm/i915/i915_config.c
@@ -6,7 +6,7 @@
 #include <linux/kernel.h>
 
 #include "i915_config.h"
-#include "i915_utils.h"
+#include "i915_jiffies.h"
 
 unsigned long
 i915_fence_context_timeout(const struct drm_i915_private *i915, u64 context)
diff --git a/drivers/gpu/drm/i915/i915_jiffies.h b/drivers/gpu/drm/i915/i915_jiffies.h
new file mode 100644
index 000000000000..18a4eaea897a
--- /dev/null
+++ b/drivers/gpu/drm/i915/i915_jiffies.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: MIT */
+/* Copyright © 2025 Intel Corporation */
+
+#ifndef __I915_JIFFIES_H__
+#define __I915_JIFFIES_H__
+
+#include <linux/jiffies.h>
+
+static inline unsigned long msecs_to_jiffies_timeout(const unsigned int m)
+{
+	unsigned long j = msecs_to_jiffies(m);
+
+	return min_t(unsigned long, MAX_JIFFY_OFFSET, j + 1);
+}
+
+#endif /* __I915_JIFFIES_H__ */
diff --git a/drivers/gpu/drm/i915/i915_utils.h b/drivers/gpu/drm/i915/i915_utils.h
index a0c892e4c40d..44de4a4aa84a 100644
--- a/drivers/gpu/drm/i915/i915_utils.h
+++ b/drivers/gpu/drm/i915/i915_utils.h
@@ -100,40 +100,6 @@ static inline bool is_power_of_2_u64(u64 n)
 	return (n != 0 && ((n & (n - 1)) == 0));
 }
 
-static inline unsigned long msecs_to_jiffies_timeout(const unsigned int m)
-{
-	unsigned long j = msecs_to_jiffies(m);
-
-	return min_t(unsigned long, MAX_JIFFY_OFFSET, j + 1);
-}
-
-/*
- * If you need to wait X milliseconds between events A and B, but event B
- * doesn't happen exactly after event A, you record the timestamp (jiffies) of
- * when event A happened, then just before event B you call this function and
- * pass the timestamp as the first argument, and X as the second argument.
- */
-static inline void
-wait_remaining_ms_from_jiffies(unsigned long timestamp_jiffies, int to_wait_ms)
-{
-	unsigned long target_jiffies, tmp_jiffies, remaining_jiffies;
-
-	/*
-	 * Don't re-read the value of "jiffies" every time since it may change
-	 * behind our back and break the math.
-	 */
-	tmp_jiffies = jiffies;
-	target_jiffies = timestamp_jiffies +
-			 msecs_to_jiffies_timeout(to_wait_ms);
-
-	if (time_after(target_jiffies, tmp_jiffies)) {
-		remaining_jiffies = target_jiffies - tmp_jiffies;
-		while (remaining_jiffies)
-			remaining_jiffies =
-			    schedule_timeout_uninterruptible(remaining_jiffies);
-	}
-}
-
 #define KHz(x) (1000 * (x))
 #define MHz(x) KHz(1000 * (x))
 
diff --git a/drivers/gpu/drm/i915/selftests/i915_selftest.c b/drivers/gpu/drm/i915/selftests/i915_selftest.c
index 9c276c9d0a75..8460f0a70d04 100644
--- a/drivers/gpu/drm/i915/selftests/i915_selftest.c
+++ b/drivers/gpu/drm/i915/selftests/i915_selftest.c
@@ -30,6 +30,7 @@
 
 #include "i915_driver.h"
 #include "i915_drv.h"
+#include "i915_jiffies.h"
 #include "i915_selftest.h"
 #include "i915_wait_util.h"
 #include "igt_flush_test.h"