[igt-dev] [PATCH i-g-t v4 1/6] lib/v3d: Add V3D packet helpers

[Maíra Canal]

In order to make a valid job submission to V3D, some packet helpers are
needed. They are responsible for handling the data and packing it
properly. Moreover, they reuse some of the generic packet helpers from
Mesa, the bit pack helpers. Therefore, add Mesa V3D's packet helpers for
IGT use.

Reviewed-by: Melissa Wen <mwen at igalia.com>
Signed-off-by: Maíra Canal <mcanal at igalia.com>
---
 lib/bitpack_helpers.h        |  60 ++++++++++++++++++++
 lib/v3d/v3d_packet_helpers.h | 104 +++++++++++++++++++++++++++++++++++
 2 files changed, 164 insertions(+)
 create mode 100644 lib/bitpack_helpers.h
 create mode 100644 lib/v3d/v3d_packet_helpers.h

diff --git a/lib/bitpack_helpers.h b/lib/bitpack_helpers.h
new file mode 100644
index 00000000..e93c695f
--- /dev/null
+++ b/lib/bitpack_helpers.h
@@ -0,0 +1,60 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright (C) 2016 Intel Corporation
+ */
+
+#ifndef UTIL_BITPACK_HELPERS_H
+#define UTIL_BITPACK_HELPERS_H
+
+#include <math.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+#ifndef util_bitpack_validate_value
+#define util_bitpack_validate_value(x)
+#endif
+
+/** Set a single bit */
+#define BITFIELD64_BIT(b)      (1ull << (b))
+/** Set all bits up to excluding bit b */
+#define BITFIELD64_MASK(b)      \
+	((b) == 64 ? (~0ull) : BITFIELD64_BIT(b) - 1)
+
+static inline uint64_t
+util_bitpack_uint(uint64_t v, uint32_t start, __attribute__((unused)) uint32_t end)
+{
+	util_bitpack_validate_value(v);
+	return v << start;
+}
+
+static inline uint64_t
+util_bitpack_sint(int64_t v, uint32_t start, uint32_t end)
+{
+	const int bits = end - start + 1;
+	const uint64_t mask = BITFIELD64_MASK(bits);
+
+	return (v & mask) << start;
+}
+
+static inline uint64_t
+util_bitpack_sfixed(float v, uint32_t start, uint32_t end,
+		    uint32_t fract_bits)
+{
+	const float factor = (1 << fract_bits);
+	const int64_t int_val = llroundf(v * factor);
+	const uint64_t mask = ~0ull >> (64 - (end - start + 1));
+
+	return (int_val & mask) << start;
+}
+
+static inline uint64_t
+util_bitpack_ufixed(float v, uint32_t start, __attribute__((unused)) uint32_t end,
+		    uint32_t fract_bits)
+{
+	const float factor = (1 << fract_bits);
+	const uint64_t uint_val = llroundf(v * factor);
+
+	return uint_val << start;
+}
+
+#endif /* UTIL_BITPACK_HELPERS_H */
diff --git a/lib/v3d/v3d_packet_helpers.h b/lib/v3d/v3d_packet_helpers.h
new file mode 100644
index 00000000..8428c275
--- /dev/null
+++ b/lib/v3d/v3d_packet_helpers.h
@@ -0,0 +1,104 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright (C) 2016 Intel Corporation
+ */
+
+#ifndef MESA_V3D_PACKET_HELPERS_H
+#define MESA_V3D_PACKET_HELPERS_H
+
+#include <assert.h>
+#include <stdint.h>
+
+#include "bitpack_helpers.h"
+
+/*
+ * Copied from Mesa's u_math.h
+ */
+union fi {
+	float f;
+	int32_t i;
+	uint32_t ui;
+};
+
+static inline float uif(uint32_t ui)
+{
+	union fi fi;
+
+	fi.ui = ui;
+	return fi.f;
+}
+
+static inline unsigned int fui(float f)
+{
+	union fi fi;
+
+	fi.f = f;
+	return fi.ui;
+}
+
+static inline uint64_t
+__gen_unpack_uint(const uint8_t *restrict cl, uint32_t start, uint32_t end)
+{
+	uint64_t val = 0;
+	const int width = end - start + 1;
+	const uint32_t mask = (width == 32 ? ~0 : (1 << width) - 1);
+
+	for (uint32_t byte = start / 8; byte <= end / 8; byte++)
+		val |= cl[byte] << ((byte - start / 8) * 8);
+
+	return (val >> (start % 8)) & mask;
+}
+
+static inline uint64_t
+__gen_unpack_sint(const uint8_t *restrict cl, uint32_t start, uint32_t end)
+{
+	int size = end - start + 1;
+	int64_t val = __gen_unpack_uint(cl, start, end);
+
+	/* Get the sign bit extended. */
+	return (val << (64 - size)) >> (64 - size);
+}
+
+static inline float
+__gen_unpack_sfixed(const uint8_t *restrict cl, uint32_t start, uint32_t end,
+		    uint32_t fractional_size)
+{
+	int32_t bits = __gen_unpack_sint(cl, start, end);
+
+	return (float)bits / (1 << fractional_size);
+}
+
+static inline float
+__gen_unpack_ufixed(const uint8_t *restrict cl, uint32_t start, uint32_t end,
+		    uint32_t fractional_size)
+{
+	int32_t bits = __gen_unpack_uint(cl, start, end);
+
+	return (float)bits / (1 << fractional_size);
+}
+
+static inline float
+__gen_unpack_float(const uint8_t *restrict cl, uint32_t start, uint32_t end)
+{
+	struct PACKED { float f; } *f;
+
+	assert(start % 8 == 0);
+	assert(end - start == 31);
+
+	f = (void *)(cl + (start / 8));
+
+	return f->f;
+}
+
+static inline float
+__gen_unpack_f187(const uint8_t *restrict cl, uint32_t start, uint32_t end)
+{
+	uint32_t bits;
+
+	assert(end - start == 15);
+
+	bits = __gen_unpack_uint(cl, start, end);
+	return uif(bits << 16);
+}
+
+#endif
-- 
2.39.1