From 76cb841cb886eef6b3bee341a2266c76578724ad Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Mon, 6 May 2024 03:02:30 +0200
Subject: Adding upstream version 4.19.249.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 drivers/gpu/drm/lib/drm_random.c | 42 ++++++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/lib/drm_random.h | 26 +++++++++++++++++++++++++
 2 files changed, 68 insertions(+)
 create mode 100644 drivers/gpu/drm/lib/drm_random.c
 create mode 100644 drivers/gpu/drm/lib/drm_random.h

(limited to 'drivers/gpu/drm/lib')

diff --git a/drivers/gpu/drm/lib/drm_random.c b/drivers/gpu/drm/lib/drm_random.c
new file mode 100644
index 000000000..eeb155826
--- /dev/null
+++ b/drivers/gpu/drm/lib/drm_random.c
@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/bitops.h>
+#include <linux/kernel.h>
+#include <linux/random.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#include "drm_random.h"
+
+static inline u32 drm_prandom_u32_max_state(u32 ep_ro, struct rnd_state *state)
+{
+	return upper_32_bits((u64)prandom_u32_state(state) * ep_ro);
+}
+
+void drm_random_reorder(unsigned int *order, unsigned int count,
+			struct rnd_state *state)
+{
+	unsigned int i, j;
+
+	for (i = 0; i < count; ++i) {
+		BUILD_BUG_ON(sizeof(unsigned int) > sizeof(u32));
+		j = drm_prandom_u32_max_state(count, state);
+		swap(order[i], order[j]);
+	}
+}
+EXPORT_SYMBOL(drm_random_reorder);
+
+unsigned int *drm_random_order(unsigned int count, struct rnd_state *state)
+{
+	unsigned int *order, i;
+
+	order = kmalloc_array(count, sizeof(*order), GFP_KERNEL);
+	if (!order)
+		return order;
+
+	for (i = 0; i < count; i++)
+		order[i] = i;
+
+	drm_random_reorder(order, count, state);
+	return order;
+}
+EXPORT_SYMBOL(drm_random_order);
diff --git a/drivers/gpu/drm/lib/drm_random.h b/drivers/gpu/drm/lib/drm_random.h
new file mode 100644
index 000000000..4a3e94dfa
--- /dev/null
+++ b/drivers/gpu/drm/lib/drm_random.h
@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __DRM_RANDOM_H__
+#define __DRM_RANDOM_H__
+
+/* This is a temporary home for a couple of utility functions that should
+ * be transposed to lib/ at the earliest convenience.
+ */
+
+#include <linux/random.h>
+
+#define DRM_RND_STATE_INITIALIZER(seed__) ({				\
+	struct rnd_state state__;					\
+	prandom_seed_state(&state__, (seed__));				\
+	state__;							\
+})
+
+#define DRM_RND_STATE(name__, seed__) \
+	struct rnd_state name__ = DRM_RND_STATE_INITIALIZER(seed__)
+
+unsigned int *drm_random_order(unsigned int count,
+			       struct rnd_state *state);
+void drm_random_reorder(unsigned int *order,
+			unsigned int count,
+			struct rnd_state *state);
+
+#endif /* !__DRM_RANDOM_H__ */
-- 
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