ARC: nSIM: switch from ARC UART to DW UART

Since v2019.06 DesingWare nSIM supports DesignWare UART simulation
and so we may switch from pretty unusual ARC UART to much more standard
DesignWare UART (which in case of U-Boot is just an ordinary 16650 UART).

This among other things makes built dinaries compatible with our other
platforms to name a few: FPGA-based HAPS boards, QEMU and even ZeBU.
Signed-off-by: NAlexey Brodkin <abrodkin@synopsys.com>

arch/arc/dts/nsim.dts

 // SPDX-License-Identifier: GPL-2.0+
 /*
- * Copyright (C) 2015-2016 Synopsys, Inc. (www.synopsys.com)
+ * Copyright (C) 2015-2016, 2020 Synopsys, Inc. (www.synopsys.com)
  */
 /dts-v1/;
 
@@ -10,7 +10,7 @@
 	model = "snps,nsim";
 
 	aliases {
-		console = &arcuart0;
+		console = &uart0;
 	};
 
 	cpu_card {
@@ -22,9 +22,11 @@
 		};
 	};
 
-	arcuart0: serial@0xc0fc1000 {
-		compatible = "snps,arc-uart";
-		reg = <0xc0fc1000 0x100>;
+	uart0: serial@f0000000 {
+		compatible = "snps,dw-apb-uart";
+		reg = <0xf0000000 0x1000>;
+		reg-shift = <2>;
+		reg-io-width = <4>;
 		clock-frequency = <70000000>;
 	};
 

configs/nsim_700_defconfig

 CONFIG_ARC=y
 CONFIG_TARGET_NSIM=y
 CONFIG_SYS_TEXT_BASE=0x81000000
-CONFIG_DEBUG_UART_BASE=0xc0fc1000
+CONFIG_DEBUG_UART_BASE=0xf0000000
 CONFIG_DEBUG_UART_CLOCK=70000000
 CONFIG_SYS_CLK_FREQ=70000000
 CONFIG_DEBUG_UART=y
 CONFIG_BOOTDELAY=3
 CONFIG_USE_BOOTARGS=y
-CONFIG_BOOTARGS="console=ttyARC0,115200n8"
+CONFIG_BOOTARGS="console=ttyS0,115200n8"
 CONFIG_SYS_PROMPT="nsim# "
 # CONFIG_CMD_SETEXPR is not set
 CONFIG_OF_CONTROL=y
@@ -16,6 +16,6 @@ CONFIG_DEFAULT_DEVICE_TREE="nsim"
 CONFIG_SYS_RELOC_GD_ENV_ADDR=y
 CONFIG_DM=y
 CONFIG_DM_SERIAL=y
-CONFIG_DEBUG_ARC_SERIAL=y
-CONFIG_ARC_SERIAL=y
+CONFIG_DEBUG_UART_SHIFT=2
+CONFIG_SYS_NS16550=y
 CONFIG_USE_PRIVATE_LIBGCC=y

configs/nsim_700be_defconfig

@@ -2,13 +2,13 @@ CONFIG_ARC=y
 CONFIG_CPU_BIG_ENDIAN=y
 CONFIG_TARGET_NSIM=y
 CONFIG_SYS_TEXT_BASE=0x81000000
-CONFIG_DEBUG_UART_BASE=0xc0fc1000
+CONFIG_DEBUG_UART_BASE=0xf0000000
 CONFIG_DEBUG_UART_CLOCK=70000000
 CONFIG_SYS_CLK_FREQ=70000000
 CONFIG_DEBUG_UART=y
 CONFIG_BOOTDELAY=3
 CONFIG_USE_BOOTARGS=y
-CONFIG_BOOTARGS="console=ttyARC0,115200n8"
+CONFIG_BOOTARGS="console=ttyS0,115200n8"
 CONFIG_SYS_PROMPT="nsim# "
 # CONFIG_CMD_SETEXPR is not set
 CONFIG_OF_CONTROL=y
@@ -17,6 +17,6 @@ CONFIG_DEFAULT_DEVICE_TREE="nsim"
 CONFIG_SYS_RELOC_GD_ENV_ADDR=y
 CONFIG_DM=y
 CONFIG_DM_SERIAL=y
-CONFIG_DEBUG_ARC_SERIAL=y
-CONFIG_ARC_SERIAL=y
+CONFIG_DEBUG_UART_SHIFT=2
+CONFIG_SYS_NS16550=y
 CONFIG_USE_PRIVATE_LIBGCC=y

configs/nsim_hs38_defconfig

@@ -2,13 +2,13 @@ CONFIG_ARC=y
 CONFIG_ISA_ARCV2=y
 CONFIG_TARGET_NSIM=y
 CONFIG_SYS_TEXT_BASE=0x81000000
-CONFIG_DEBUG_UART_BASE=0xc0fc1000
+CONFIG_DEBUG_UART_BASE=0xf0000000
 CONFIG_DEBUG_UART_CLOCK=70000000
 CONFIG_SYS_CLK_FREQ=70000000
 CONFIG_DEBUG_UART=y
 CONFIG_BOOTDELAY=3
 CONFIG_USE_BOOTARGS=y
-CONFIG_BOOTARGS="console=ttyARC0,115200n8"
+CONFIG_BOOTARGS="console=ttyS0,115200n8"
 CONFIG_SYS_PROMPT="nsim# "
 # CONFIG_CMD_SETEXPR is not set
 CONFIG_OF_CONTROL=y
@@ -17,6 +17,6 @@ CONFIG_DEFAULT_DEVICE_TREE="nsim"
 CONFIG_SYS_RELOC_GD_ENV_ADDR=y
 CONFIG_DM=y
 CONFIG_DM_SERIAL=y
-CONFIG_DEBUG_ARC_SERIAL=y
-CONFIG_ARC_SERIAL=y
+CONFIG_DEBUG_UART_SHIFT=2
+CONFIG_SYS_NS16550=y
 CONFIG_USE_PRIVATE_LIBGCC=y

configs/nsim_hs38be_defconfig

@@ -3,13 +3,13 @@ CONFIG_ISA_ARCV2=y
 CONFIG_CPU_BIG_ENDIAN=y
 CONFIG_TARGET_NSIM=y
 CONFIG_SYS_TEXT_BASE=0x81000000
-CONFIG_DEBUG_UART_BASE=0xc0fc1000
+CONFIG_DEBUG_UART_BASE=0xf0000000
 CONFIG_DEBUG_UART_CLOCK=70000000
 CONFIG_SYS_CLK_FREQ=70000000
 CONFIG_DEBUG_UART=y
 CONFIG_BOOTDELAY=3
 CONFIG_USE_BOOTARGS=y
-CONFIG_BOOTARGS="console=ttyARC0,115200n8"
+CONFIG_BOOTARGS="console=ttyS0,115200n8"
 CONFIG_SYS_PROMPT="nsim# "
 # CONFIG_CMD_SETEXPR is not set
 CONFIG_OF_CONTROL=y
@@ -18,6 +18,6 @@ CONFIG_DEFAULT_DEVICE_TREE="nsim"
 CONFIG_SYS_RELOC_GD_ENV_ADDR=y
 CONFIG_DM=y
 CONFIG_DM_SERIAL=y
-CONFIG_DEBUG_ARC_SERIAL=y
-CONFIG_ARC_SERIAL=y
+CONFIG_DEBUG_UART_SHIFT=2
+CONFIG_SYS_NS16550=y
 CONFIG_USE_PRIVATE_LIBGCC=y