alveo_u280: Fix copyrights (avoid too much cascading on Platforms/Targets) and...

alveo_u280: Fix copyrights (avoid too much cascading on Platforms/Targets) and generate reset on idelay clock domain (similarly to recent change on others Ultrascale+ boards).

litex_boards/platforms/alveo_u280.py

 #
 # This file is part of LiteX-Boards.
 #
-# Copyright (c) 2020 David Shah <dave@ds0.me>
-# Copyright (c) 2020 Florent Kermarrec <florent@enjoy-digital.fr>
+# Copyright (c) 2021 Sergiu Mosanu <sm7ed@virginia.edu>
+#
 # SPDX-License-Identifier: BSD-2-Clause
 
-# Modified for Alveo U280 by Sergiu Mosanu based on XCU1525 and Alveo U250
-
 from litex.build.generic_platform import Pins, Subsignal, IOStandard, Misc
 from litex.build.xilinx import XilinxPlatform, VivadoProgrammer
 
@@ -31,12 +29,12 @@ _io = [
     ("gpio_led", 2, Pins("D31"), IOStandard("LVCMOS18")),
 
     # Switches
-    
+
     ("gpio_sw", 0, Pins("J30"), IOStandard("LVCMOS18")),
     ("gpio_sw", 1, Pins("J32"), IOStandard("LVCMOS18")),
     ("gpio_sw", 2, Pins("K32"), IOStandard("LVCMOS18")),
     ("gpio_sw", 3, Pins("K31"), IOStandard("LVCMOS18")),
-    
+
     # Serial
     ("serial", 0,
         Subsignal("rx", Pins("A28"), IOStandard("LVCMOS18")),

litex_boards/targets/alveo_u280.py

@@ -3,10 +3,8 @@
 #
 # This file is part of LiteX-Boards.
 #
-# Copyright (c) 2020 Fei Gao <feig@princeton.edu>
-# Copyright (c) 2020 Florent Kermarrec <florent@enjoy-digital.fr>
-# Copyright (c) 2020 David Shah <dave@ds0.me>
-# Modified for Alveo U280 by Sergiu Mosanu based on XCU1525 and Alveo U250
+# Copyright (c) 2021 Sergiu Mosanu <sm7ed@virginia.edu>
+#
 # SPDX-License-Identifier: BSD-2-Clause
 
 import argparse, os
@@ -44,7 +42,7 @@ class _CRG(Module):
         self.comb += pll.reset.eq(self.rst)
         pll.register_clkin(platform.request("sysclk", ddram_channel), 100e6)
         pll.create_clkout(self.cd_pll4x, sys_clk_freq*4, buf=None, with_reset=False)
-        pll.create_clkout(self.cd_idelay, 500e6, with_reset=False)
+        pll.create_clkout(self.cd_idelay, 500e6)
         platform.add_false_path_constraints(self.cd_sys.clk, pll.clkin) # Ignore sys_clk to pll.clkin path created by SoC's rst.
 
         self.specials += [