[arch][riscv] Add basic support for SiFive HiFive Unleashed

Most of changes were moving around where macros were defined, plus the
following:
- Remove requirement for floating point on RV64 to support booting
  monitor core on U54 SoC.
- Add support for Debug LEDs on HiFive Unleashed Board

target/sifive-e/include/platform/sifive.h

@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 2018 Travis Geiselbrecht
+ *
+ * Use of this source code is governed by a MIT-style
+ * license that can be found in the LICENSE file or at
+ * https://opensource.org/licenses/MIT
+ */
+#pragma once
+
+#define SIFIVE_IRQ_UART0 3
+#define SIFIVE_IRQ_UART1 4
+
+#define SIFIVE_NUM_IRQS 127
+
+#define CLINT_BASE 0x02000000
+#define PLIC_BASE  0x0c000000
+#define PRCI_BASE  0x10008000
+#define GPIO_BASE  0x10012000
+#define UART0_BASE 0x10013000
+
+#define GPIO_REG_VALUE      0
+#define GPIO_REG_INPUT_EN   1
+#define GPIO_REG_OUTPUT_EN  2
+#define GPIO_REG_PORT       3
+#define GPIO_REG_IOF_EN     14
+#define GPIO_REG_IOF_SEL    15
+

target/sifive-e/rules.mk

@@ -13,5 +13,10 @@ GLOBAL_DEFINES += SIFIVE_FREQ=16000000
 
 MODULE_SRCS := $(LOCAL_DIR)/target.c
 
+# set some global defines based on capability
+GLOBAL_DEFINES += PLATFORM_HAS_DYNAMIC_TIMER=1
+GLOBAL_DEFINES += ARCH_RISCV_CLINT_BASE=0x02000000
+GLOBAL_DEFINES += ARCH_RISCV_MTIME_RATE=32768
+
 include make/module.mk
 

target/sifive-unleashed/include/platform/sifive.h

@@ -0,0 +1,22 @@
+/*
+ * Copyright (c) 2019 Elliot Berman
+ *
+ * Use of this source code is governed by a MIT-style
+ * license that can be found in the LICENSE file or at
+ * https://opensource.org/licenses/MIT
+ */
+#pragma once
+
+#define SIFIVE_IRQ_UART0 4
+#define SIFIVE_IRQ_UART1 5
+
+#define SIFIVE_NUM_IRQS 53
+
+#define CLINT_BASE 0x02000000
+#define PLIC_BASE  0x0c000000
+#define PRCI_BASE  0x10000000
+#define UART0_BASE 0x10010000
+#define UART1_BASE 0x10011000
+#define PWM0_BASE  0x10020000
+#define PWM1_BASE  0x10021000
+#define GPIO_BASE  0x10060000

target/sifive-unleashed/rules.mk

@@ -0,0 +1,19 @@
+LOCAL_DIR := $(GET_LOCAL_DIR)
+MODULE := $(LOCAL_DIR)
+
+PLATFORM := sifive
+VARIANT := sifive_u
+
+GLOBAL_DEFINES += SIFIVE_FREQ=500000000 # 500 MHz
+
+MEMBASE ?= 0x080000000
+MEMSIZE ?= 0x200000000 # 8 GiB
+
+MODULE_SRCS := $(LOCAL_DIR)/target.c
+# set some global defines based on capability
+GLOBAL_DEFINES += TARGET_HAS_DEBUG_LED=1
+GLOBAL_DEFINES += PLATFORM_HAS_DYNAMIC_TIMER=1
+GLOBAL_DEFINES += ARCH_RISCV_CLINT_BASE=0x02000000
+GLOBAL_DEFINES += ARCH_RISCV_MTIME_RATE=1000000  # 1 MHz
+
+include make/module.mk

target/sifive-unleashed/target.c

@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2019 Elliot Berman
+ *
+ * Use of this source code is governed by a MIT-style
+ * license that can be found in the LICENSE file or at
+ * https://opensource.org/licenses/MIT
+ */
+
+#include <target.h>
+#include <arch/arch_ops.h>
+#include <platform/sifive.h>
+
+static volatile struct {
+	volatile uint32_t pwmcfg;
+	volatile uint32_t res0;
+	volatile uint32_t pwmcount;
+	volatile uint32_t res1;
+	volatile uint32_t pwms;
+	volatile uint32_t res2[3];
+	volatile uint32_t pwmcmp[4];
+} *const pwm0_base = (void*)PWM0_BASE;
+
+void target_early_init(void) {
+	pwm0_base->pwmcfg = 0x100f; // enable always and max scaling
+	target_set_debug_led(0, false);
+	target_set_debug_led(1, false);
+	target_set_debug_led(2, false);
+	target_set_debug_led(3, false);
+}
+
+void target_init(void) {
+}
+
+void target_set_debug_led(unsigned int led, bool on) {
+	if(led > 3)
+		return;
+	pwm0_base->pwmcmp[led] = (0xffff + on) & 0xffff;
+}