From 36d0a8b3e8b58ad57b9ffdc497f3687afe0269ea Mon Sep 17 00:00:00 2001
From: Laszlo Nagy <laszlo.nagy@analog.com>
Date: Wed, 3 Mar 2021 11:51:16 +0000
Subject: [PATCH] library:util_pad: Initial version

Data to DMA/system memory must be presented in widths of multiple of 8 bits,
however this padding is not optimal if is done in the transport layer
since this will affect the DAC/ADC FIFO or offload storage.

This utility block adds or removes padding from sample stream in case the
sample with is not multiple of 8 bits, and can be placed between the DMA
and FIFO/Offload blocks.
---
 library/Makefile                 |  2 +
 library/util_pad/Makefile        | 13 ++++++
 library/util_pad/util_pad.v      | 71 ++++++++++++++++++++++++++++++++
 library/util_pad/util_pad_ip.tcl | 12 ++++++
 4 files changed, 98 insertions(+)
 create mode 100644 library/util_pad/Makefile
 create mode 100644 library/util_pad/util_pad.v
 create mode 100644 library/util_pad/util_pad_ip.tcl

diff --git a/library/Makefile b/library/Makefile
index 69e6b2b18..1fdeb88c2 100644
--- a/library/Makefile
+++ b/library/Makefile
@@ -116,6 +116,7 @@ clean:
 	$(MAKE) -C util_mfifo clean
 	$(MAKE) -C util_pack/util_cpack2 clean
 	$(MAKE) -C util_pack/util_upack2 clean
+	$(MAKE) -C util_pad clean
 	$(MAKE) -C util_pulse_gen clean
 	$(MAKE) -C util_rfifo clean
 	$(MAKE) -C util_sigma_delta_spi clean
@@ -239,6 +240,7 @@ lib:
 	$(MAKE) -C util_mfifo
 	$(MAKE) -C util_pack/util_cpack2
 	$(MAKE) -C util_pack/util_upack2
+	$(MAKE) -C util_pad
 	$(MAKE) -C util_pulse_gen
 	$(MAKE) -C util_rfifo
 	$(MAKE) -C util_sigma_delta_spi
diff --git a/library/util_pad/Makefile b/library/util_pad/Makefile
new file mode 100644
index 000000000..529e11068
--- /dev/null
+++ b/library/util_pad/Makefile
@@ -0,0 +1,13 @@
+####################################################################################
+## Copyright (c) 2018 - 2021 Analog Devices, Inc.
+### SPDX short identifier: BSD-1-Clause
+## Auto-generated, do not modify!
+####################################################################################
+
+LIBRARY_NAME := util_pad
+
+GENERIC_DEPS += util_pad.v
+
+XILINX_DEPS += util_pad_ip.tcl
+
+include ../scripts/library.mk
diff --git a/library/util_pad/util_pad.v b/library/util_pad/util_pad.v
new file mode 100644
index 000000000..84caf244b
--- /dev/null
+++ b/library/util_pad/util_pad.v
@@ -0,0 +1,71 @@
+// ***************************************************************************
+// ***************************************************************************
+// Copyright 2018 (c) Analog Devices, Inc. All rights reserved.
+//
+// Each core or library found in this collection may have its own licensing terms.
+// The user should keep this in in mind while exploring these cores.
+//
+// Redistribution and use in source and binary forms,
+// with or without modification of this file, are permitted under the terms of either
+//  (at the option of the user):
+//
+//   1. The GNU General Public License version 2 as published by the
+//      Free Software Foundation, which can be found in the top level directory, or at:
+// https://www.gnu.org/licenses/old-licenses/gpl-2.0.en.html
+//
+// OR
+//
+//   2.  An ADI specific BSD license as noted in the top level directory, or on-line at:
+// https://github.com/analogdevicesinc/hdl/blob/dev/LICENSE
+//
+// ***************************************************************************
+// ***************************************************************************
+
+`timescale 1ns/100ps
+
+module util_pad #(
+  parameter NUM_OF_SAMPLES = 2,
+  parameter IN_BITS_PER_SAMPLE = 16,
+  parameter OUT_BITS_PER_SAMPLE = 16,
+  parameter PADDING_TO_MSB_LSB_N = 0,
+  parameter SIGN_EXTEND = 1
+) (
+  input [NUM_OF_SAMPLES*IN_BITS_PER_SAMPLE-1:0] data_in,
+  output reg [NUM_OF_SAMPLES*OUT_BITS_PER_SAMPLE-1:0] data_out
+);
+
+// Remove padding
+if (IN_BITS_PER_SAMPLE >= OUT_BITS_PER_SAMPLE) begin
+  integer i;
+  always @(*) begin
+    for (i=0;i<NUM_OF_SAMPLES;i=i+1) begin
+      if (PADDING_TO_MSB_LSB_N==1) begin
+        data_out[i*OUT_BITS_PER_SAMPLE +: OUT_BITS_PER_SAMPLE] =
+          data_in[i*IN_BITS_PER_SAMPLE +: OUT_BITS_PER_SAMPLE];
+      end else begin
+        data_out[i*OUT_BITS_PER_SAMPLE +: OUT_BITS_PER_SAMPLE] =
+          data_in[((i+1)*IN_BITS_PER_SAMPLE)-1 -: OUT_BITS_PER_SAMPLE];
+      end
+    end
+  end
+end
+
+// Add padding
+if (IN_BITS_PER_SAMPLE < OUT_BITS_PER_SAMPLE) begin
+  integer i;
+  always @(*) begin
+    for (i=0;i<NUM_OF_SAMPLES;i=i+1) begin
+      if (PADDING_TO_MSB_LSB_N==1) begin
+        data_out[i*OUT_BITS_PER_SAMPLE +: OUT_BITS_PER_SAMPLE] =
+          {{OUT_BITS_PER_SAMPLE-IN_BITS_PER_SAMPLE{data_in[(i+1)*IN_BITS_PER_SAMPLE-1]&SIGN_EXTEND[0]}},
+          data_in[i*IN_BITS_PER_SAMPLE +: OUT_BITS_PER_SAMPLE]};
+      end else begin
+        data_out[i*OUT_BITS_PER_SAMPLE +: OUT_BITS_PER_SAMPLE] =
+          {data_in[((i+1)*IN_BITS_PER_SAMPLE)-1 -: OUT_BITS_PER_SAMPLE],
+          {OUT_BITS_PER_SAMPLE-IN_BITS_PER_SAMPLE{1'b0}}};
+      end
+    end
+  end
+end
+
+endmodule
diff --git a/library/util_pad/util_pad_ip.tcl b/library/util_pad/util_pad_ip.tcl
new file mode 100644
index 000000000..6076922a1
--- /dev/null
+++ b/library/util_pad/util_pad_ip.tcl
@@ -0,0 +1,12 @@
+# ip
+
+source ../scripts/adi_env.tcl
+source $ad_hdl_dir/library/scripts/adi_ip_xilinx.tcl
+
+adi_ip_create util_pad
+adi_ip_files util_pad [list \
+  "util_pad.v" ]
+
+adi_ip_properties_lite util_pad
+
+ipx::save_core [ipx::current_core]