From 5190c9c869ad61c9940a8b8a766b6808382e934c Mon Sep 17 00:00:00 2001
From: Florent Kermarrec <florent@enjoy-digital.fr>
Date: Mon, 20 Sep 2021 09:32:20 +0200
Subject: [PATCH] sipeed_tang_nano_4k: Initial Video Out support.

With colorbars for now, need to free up BRAMS for Video Terminal (or finish HyperRAM support).
---
 litex_boards/platforms/sipeed_tang_nano_4k.py |  5 ++--
 litex_boards/targets/sipeed_tang_nano_4k.py   | 29 +++++++++++++++++--
 2 files changed, 28 insertions(+), 6 deletions(-)

diff --git a/litex_boards/platforms/sipeed_tang_nano_4k.py b/litex_boards/platforms/sipeed_tang_nano_4k.py
index 1dfcf87..83c609a 100644
--- a/litex_boards/platforms/sipeed_tang_nano_4k.py
+++ b/litex_boards/platforms/sipeed_tang_nano_4k.py
@@ -59,8 +59,8 @@ _io = [
     ("IO_hpram_dq",     0, Pins(8), IOStandard("LVCMOS33")),
     ("IO_hpram_rwds",   0, Pins(1), IOStandard("LVCMOS33")),
 
-    # HDMI Out.
-    ("hdmi_out", 0,
+    # HDMI.
+    ("hdmi", 0,
         Subsignal("clk_p",   Pins("28")),
         Subsignal("clk_n",   Pins("27")),
         Subsignal("data0_p", Pins("30")),
@@ -70,7 +70,6 @@ _io = [
         Subsignal("data2_p", Pins("35")),
         Subsignal("data2_n", Pins("34")),
         Misc("PULL_MODE=NONE"),
-        Misc("DRIVE=3.5"),
     ),
 ]
 
diff --git a/litex_boards/targets/sipeed_tang_nano_4k.py b/litex_boards/targets/sipeed_tang_nano_4k.py
index 74cea57..a3e6c1e 100755
--- a/litex_boards/targets/sipeed_tang_nano_4k.py
+++ b/litex_boards/targets/sipeed_tang_nano_4k.py
@@ -17,6 +17,7 @@ from litex.soc.integration.soc_core import *
 from litex.soc.integration.soc import SoCRegion
 from litex.soc.integration.builder import *
 from litex.soc.cores.led import LedChaser
+from litex.soc.cores.video import *
 
 from litex_boards.platforms import tang_nano_4k
 
@@ -28,7 +29,7 @@ mB = 1024*kB
 # CRG ----------------------------------------------------------------------------------------------
 
 class _CRG(Module):
-    def __init__(self, platform, sys_clk_freq):
+    def __init__(self, platform, sys_clk_freq, with_video_pll=False):
         self.rst = Signal()
         self.clock_domains.cd_sys = ClockDomain()
 
@@ -44,11 +45,27 @@ class _CRG(Module):
         pll.register_clkin(clk27, 27e6)
         pll.create_clkout(self.cd_sys, sys_clk_freq)
 
+
+        # Video PLL
+        if with_video_pll:
+            self.submodules.video_pll = video_pll = GW1NSRPLL(device="GW1NSR-4C")
+            self.comb += video_pll.reset.eq(~rst_n)
+            video_pll.register_clkin(clk27, 27e6)
+            self.clock_domains.cd_hdmi   = ClockDomain()
+            self.clock_domains.cd_hdmi5x = ClockDomain()
+            video_pll.create_clkout(self.cd_hdmi5x, 125e6)
+            self.specials += Instance("CLKDIV",
+                p_DIV_MODE= "5",
+                i_RESETN = rst_n,
+                i_HCLKIN = self.cd_hdmi5x.clk,
+                o_CLKOUT = self.cd_hdmi.clk
+            )
+
 # BaseSoC ------------------------------------------------------------------------------------------
 
 class BaseSoC(SoCCore):
     mem_map = {**SoCCore.mem_map, **{"spiflash": 0x80000000}}
-    def __init__(self, sys_clk_freq=int(27e6), with_hyperram=True, with_led_chaser=True, **kwargs):
+    def __init__(self, sys_clk_freq=int(27e6), with_hyperram=False, with_led_chaser=True, with_video_terminal=True, **kwargs):
         platform = tang_nano_4k.Platform()
 
         # Put BIOS in SPIFlash to save BlockRAMs.
@@ -62,7 +79,7 @@ class BaseSoC(SoCCore):
             **kwargs)
 
         # CRG --------------------------------------------------------------------------------------
-        self.submodules.crg = _CRG(platform, sys_clk_freq)
+        self.submodules.crg = _CRG(platform, sys_clk_freq, with_video_pll=with_video_terminal)
 
         # SPI Flash --------------------------------------------------------------------------------
         from litespi.modules import W25Q32
@@ -92,6 +109,12 @@ class BaseSoC(SoCCore):
             self.submodules.hyperram = HyperRAM(hyperram_pads)
             self.bus.add_slave("main_ram", slave=self.hyperram.bus, region=SoCRegion(origin=0x40000000, size=8*1024*1024))
 
+        # Video ------------------------------------------------------------------------------------
+        if with_video_terminal:
+            self.submodules.videophy = VideoHDMIPHY(platform.request("hdmi"), clock_domain="hdmi")
+            self.add_video_colorbars(phy=self.videophy, timings="640x480@75Hz", clock_domain="hdmi")
+            #self.add_video_terminal(phy=self.videophy, timings="640x480@75Hz", clock_domain="hdmi") # FIXME: Free up BRAMs.
+
         # Leds -------------------------------------------------------------------------------------
         if with_led_chaser:
             self.submodules.leds = LedChaser(